A survey of QoS routing solutions for mobile ad hoc networks
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paper_title: Mitigating the exposed node problem in IEEE 802.11 ad hoc networks

paper_content:

The enhancements to the IEEE 802.11 DCF MAC protocol which enable nodes to identify themselves as exposed nodes and to opportunistically schedule concurrent transmissions whenever possible, thereby improving utilization and mitigating the exposed node problem are described. The algorithm makes minimal changes to the IEEE 802.11 MAC protocol. It does not require the introduction of new frame types or changes to existing frame formats. We show, using simulations in GloMoSim, that it provides significant improvement in throughput.
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paper_title: Quality of service challenges for wireless mobile ad hoc networks

paper_content:

Wireless mobile ad hoc networks consist of mobile nodes interconnected by wireless multi-hop communication paths. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support. The topology of such networks changes dynamically as mobile nodes join or depart the network or radio links between nodes become unusable. Supporting appropriate quality of service for mobile ad hoc networks is a complex and difficult issue because of the dynamic nature of the network topology and generally imprecise network state information, and has become an intensely active area of research in the last few years. This paper1 presents the basic concepts of quality of service support in ad hoc networks for unicast communication, reviews the major areas of current research and results, and addresses some new issues. The principal focus is on routing and security issues associated with quality of service support. The paper concludes with some observations on the open areas for further investigation. Copyright © 2004 John Wiley & Sons, Ltd.
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paper_title: Routing Support for Providing Guaranteed End-To-End Quality-Of-Service

paper_content:

The up-coming Gbps high-speed networks are expected to support a wide range of real-time, communication-intensive applications. The quality-of-service (QoS) requirements for the timely delivery of multimedia information raise new challenges for the development of integrated-service broadband networks. One of the key issues is QoS routing, which allows selecting network routes with sufficient resources for requested QoS parameters. The goal of QoS routing solutions is two-fold: satisfying the QoS requirements for every admitted connection and achieving global efficiency in resource utilization. ::: Many unicast/multicast QoS routing algorithms were published recently. However, there still exist a lot of unsolved problems in this area. A few examples are listed as follows. (1) There lacks a simple solution with predictable performance and adjustable overhead for the NP-complete multi-constraint routing problem. (2) All existing algorithms are tailored towards specific problems, and there lacks a simple, general routing framework which can be easily extended to handle new problems. (3) Most routing algorithms assume the availability of precise state information about the network, which however is impractical in the real world. ::: We address the above problems, and the goal of this dissertation is to provide simple, general and extensible solutions for QoS routing. We study different routing strategies, compare them and outline the challenges. We propose various algorithms based on different network state models, evaluate these algorithms by analysis and simulation, discuss their strengths and weaknesses of different routing strategies, and compare them with the existing algorithms. The major achievement of this dissertation is outlined in the following. (1) A heuristic approach is proposed to solve the multi-constraint routing problem. It allows the dynamic tradeoff between performance and overhead. (2) A distributed routing framework is proposed to integrate a family of routing algorithms which support applications with QoS requirements on bandwidth, delay, delay jitter, cost, path length, and their combination. (3) Source and distributed routing algorithms axe proposed to work with state information which has a high degree of imprecision. (4) Distributed QoS routing algorithms are proposed for mobile ad-hoc networks whose topologies change as nodes move, join, or leave the networks. (5) An integrated framework is proposed to support routing and scheduling of co-existing QoS and best-effort flows.
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paper_title: QoS-aware routing based on bandwidth estimation for mobile ad hoc networks

paper_content:

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support.
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paper_title: Contention-aware admission control for ad hoc networks

paper_content:

An admission control algorithm must coordinate between flows to provide guarantees about how the medium is shared. In wired networks, nodes can monitor the medium to see how much bandwidth is being used. However, in ad hoc networks, communication from one node may consume the bandwidth of neighboring nodes. Therefore, the bandwidth consumption of flows and the available resources to a node are not local concepts, but related to the neighboring nodes in carrier-sensing range. Current solutions do not address how to perform admission control in such an environment so that the admitted flows in the network do not exceed network capacity. In this paper, we present a scalable and efficient admission control framework - contention-aware admission control protocol (CACP) - to support QoS in ad hoc networks. We present several options for the design of CACP and compare the performance of these options using both mathematical analysis and simulation results. We also demonstrate the effectiveness of CACP compared to existing approaches through extensive simulations.
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paper_title: Distributed Quality-of-Service Routing in Ad Hoc Networks

paper_content:

In an ad hoc network, all communication is done over wireless media, typically by radio through the air, without the help of wired base stations. Since direct communication is allowed only between adjacent nodes, distant nodes communicate over multiple hops. The quality-of-service (QoS) routing in an ad hoc network is difficult because the network topology may change constantly, and the available state information for routing is inherently imprecise. In this paper, we propose a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the most qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave the network. Our algorithms consider not only the QoS requirement, but also the cost optimality of the routing path to improve the overall network performance. Extensive simulations show that high call admission ratio and low-cost paths are achieved with modest routing overhead. The algorithms can tolerate a high degree of information imprecision.
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paper_title: QoS routing in ad hoc wireless networks

paper_content:

The emergence of nomadic applications have generated a lot of interest in wireless network infrastructures which support multimedia services. We propose a bandwidth routing algorithm for multimedia support in a multihop wireless network. This network can be interconnected to wired networks (e.g. ATM or the Internet) or stand alone. Our bandwidth routing includes bandwidth calculation and reservation schemes. Under such a routing algorithm, we can derive a route to satisfy the bandwidth requirement for the QoS constraint. At a source node, the bandwidth information can be used to decide to accept a new call or not immediately. This is specially important to carry out a fast handoff when interconnecting to an ATM backbone infrastructure. It enables an efficient call admission control. The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network. Different types of QoS traffic can be integrated in such a dynamic radio network with high performance.
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paper_title: Generalized quality-of-service routing with resource allocation

paper_content:

We present a general framework for the problem of quality-of-service (QoS) routing with resource allocation for data networks. The framework represents the QoS parameters as functions rather than static metrics. The formulation incorporates the hardware/software implementation and its relation to the allocated resources into a single framework. The proposed formulation allows intelligent adaptation of QoS parameters and allocated resources during a path search, rather than decoupling the path search process from resource allocation. We present a dynamic programming algorithm that, under certain conditions, finds an optimal path between a source and destination node and computes the amount of resources needed at each node so that the end-to-end QoS requirements are satisfied. We present jitter and data droppage analyzes of various rate-based service disciplines and use the dynamic programming algorithm to solve the problem of QoS routing with resource allocation for networks that employ these service disciplines.
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paper_title: A position-based QoS routing scheme for UWB mobile ad hoc networks

paper_content:

Ultra-wideband (UWB) wireless communication is a promising spread-spectrum technology that supports very high data rates and provides precise position information of mobile users. In this paper, we present a position-based quality-of-service (QoS) routing scheme for UWB mobile ad hoc networks. The scheme applies call admission control and temporary bandwidth reservation for discovered routes, taking into consideration the medium access control interactions. Via cross-layer design, it exploits UWB advantages at the network layer by using the position information in routing and bandwidth reservation and by supporting the multirate capability. Simulation results demonstrate that the proposed routing scheme is effective in end-to-end QoS support.
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paper_title: An application-aware qos routing scheme with improved stability for multimedia applications in mobile ad hoc networks

paper_content:

Both delay and bandwidth are the crucial node state information considered in QoS routing schemes for multimedia applications in mobile Ad Hoc networks. In this paper, we propose an application-aware QoS routing scheme for multimedia applications in mobile Ad Hoc networks. In our scheme, the real time control protocol (RTCP) is used to estimate the node state instead of the additional probing messages, and an optimally stable route can be established according to QoS requirements of the multimedia application based on the node state information. It has been shown that the routing performance is improved significantly compared to the existing schemes using the additional probing messages.
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paper_title: Distributed Quality-of-Service Routing in Ad Hoc Networks

paper_content:

In an ad hoc network, all communication is done over wireless media, typically by radio through the air, without the help of wired base stations. Since direct communication is allowed only between adjacent nodes, distant nodes communicate over multiple hops. The quality-of-service (QoS) routing in an ad hoc network is difficult because the network topology may change constantly, and the available state information for routing is inherently imprecise. In this paper, we propose a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the most qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave the network. Our algorithms consider not only the QoS requirement, but also the cost optimality of the routing path to improve the overall network performance. Extensive simulations show that high call admission ratio and low-cost paths are achieved with modest routing overhead. The algorithms can tolerate a high degree of information imprecision.
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paper_title: Routing protocol with QoS guarantees for ad-hoc network

paper_content:

A novel routing protocol for ad-hoc networks, delay sensitive adaptive routing protocol (DSARP), is presented, which not only provides a reliable route for delay-sensitive traffic, but also can select the route based on the constrained condition: ‘the shortest route and the lowest average delay’. Therefore, the DSARP is assured to provide QoS guarantee and improve the performance of the network. Simulation results show that DSARP outperforms the dynamic source routing protocol used in ad-hoc wireless networks.
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paper_title: Link stability models for QoS ad hoc routing algorithms

paper_content:

In an ad hoc network, the topology varies as a result of the mobility of its mobile hosts. Consequently, the task of performing ad hoc network routing is more complex and less efficient. Many ad hoc network routing protocols have been proposed. However, more work is required in developing scalable ad hoc routing protocols that support quality-of-service (QoS). Recently, our study shows that link stability (in term of link survival time) has great impact on QoS performance of routing in ad hoc networks. We developed a number of models which effectively estimate link stability for different network movement patterns. By implementing link stability, which is a standalone network parameter, the QoS performance of varieties of ad hoc routing algorithms could be improved when networks are subjected to topological changes, to variations in traffic loading patterns (including a multitude of traffic classes). In this paper, we show that QoS performance of AODV is improved by implementing link stability parameter.
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paper_title: QoS routing in ad hoc wireless networks

paper_content:

The emergence of nomadic applications have generated a lot of interest in wireless network infrastructures which support multimedia services. We propose a bandwidth routing algorithm for multimedia support in a multihop wireless network. This network can be interconnected to wired networks (e.g. ATM or the Internet) or stand alone. Our bandwidth routing includes bandwidth calculation and reservation schemes. Under such a routing algorithm, we can derive a route to satisfy the bandwidth requirement for the QoS constraint. At a source node, the bandwidth information can be used to decide to accept a new call or not immediately. This is specially important to carry out a fast handoff when interconnecting to an ATM backbone infrastructure. It enables an efficient call admission control. The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network. Different types of QoS traffic can be integrated in such a dynamic radio network with high performance.
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paper_title: Power-aware routing in mobile ad hoc networks

paper_content:

b this paper we present a case for using new power-aware metn.cs for determining routes in wireless ad hoc networks. We present five ~erent metriw based on battery power consumption at nodw. We show that using th=e metrics in a shortest-cost routing algorithm reduces the cost/packet of routing packets by 5-30% over shortwt-hop routing (this cost reduction is on top of a 40-70% reduction in energy consumption obtained by using PAMAS, our MAC layer prtocol). Furthermore, using these new metrics ensures that the mean time to node failure is increased si~cantly. An interesting property of using shortest-cost routing is that packet delays do not increase. Fintiy, we note that our new metrim can be used in most tradition routing protocols for ad hoc networks.
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paper_title: QoS routing using lower layer information in ad hoc networks

paper_content:

A wireless ad hoc network is an autonomous system where all nodes are capable of movement and can be connected dynamically in an arbitrary manner. Without a network infrastructure, network nodes function as routers which discover and maintain routes to other nodes in the network. Routing in ad hoc networks has received a lot of attention due to the challenges posed by the self-organizing nature of the network, the dynamic topology, and the unreliable wireless medium. Quality of service (QoS) routing searches for routes with sufficient resources for the QoS requirements and is one of the core technologies to support QoS for real-time multimedia and data applications in ad hoc networks. We show that MAC layer information can be utilized at the routing layer via certain routing metrics for optimal route selection. We propose to use MAC delay as an indication of the level of interference of a link. Link reliability and residual bandwidth are two other routing constraints. Then, the resulting NP-complete multiple constraint routing problem is solved using a heuristic algorithm. The performance of the algorithm is studied using simulations.
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paper_title: Link stability models for QoS ad hoc routing algorithms

paper_content:

In an ad hoc network, the topology varies as a result of the mobility of its mobile hosts. Consequently, the task of performing ad hoc network routing is more complex and less efficient. Many ad hoc network routing protocols have been proposed. However, more work is required in developing scalable ad hoc routing protocols that support quality-of-service (QoS). Recently, our study shows that link stability (in term of link survival time) has great impact on QoS performance of routing in ad hoc networks. We developed a number of models which effectively estimate link stability for different network movement patterns. By implementing link stability, which is a standalone network parameter, the QoS performance of varieties of ad hoc routing algorithms could be improved when networks are subjected to topological changes, to variations in traffic loading patterns (including a multitude of traffic classes). In this paper, we show that QoS performance of AODV is improved by implementing link stability parameter.
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paper_title: A QoS routing method for ad-hoc networks based on genetic algorithm

paper_content:

A lot of work has been done on routing in MANETs. However, the proposed routing resolutions deal only with the best effort data traffic. Connections with quality of service (QoS) requirements are not supported. QoS routing has been receiving increasingly intensive attention in the wireline network domain. However, for MANETs only few QoS algorithms are proposed to be developed and QoS routing algorithms should be adaptive, flexible, and intelligent. We propose a genetic algorithm (GA) based routing method for Mobile Ad-Hoc Networks (GAMAN). Robustness rather that optimality is the primary concern of GAMAN. The GAMAN uses two QoS parameters for routing. The performance evaluation via simulations shows that GAMAN is a promising QoS routing algorithm for MANETs.
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paper_title: On-demand SIR and bandwidth-guaranteed routing with transmit power assignment in ad hoc mobile networks

paper_content:

In this paper, we propose a novel on-demand quality-of-service (QoS) routing protocol, SBR [signal-to-interference (SIR) and bandwidth routing], which explicitly fulfills both SIR and bandwidth requirements from different multimedia users in ad hoc mobile networks. With SBR, bandwidth reservation is made by allocating time slots and SIR reservation is ensured by assigning adequate powers at the intermediate nodes between a source and a destination. The power-assignment method used in SBR supports finding routes that satisfy the SIR requirements as well as reduces the level of prevailing interference that necessarily occurs in multiple-access wireless networks. SBR also has a new backup capability of establishing multiple paths, even for a single connection, when the route search cannot find a single path that supports the QoS requirements, which contributes to reducing the probability of call denials in constructing the route due to a lack of suitable paths. Extensive simulations show that SBR significantly reduces the ratio of unsuccessful calls with modest routing overhead.
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paper_title: QoS provisioning using BER-based routing in ad hoc wireless networks

paper_content:

In order to guarantee a certain level of quality of service (QoS), routing protocol should be smart enough to pick a stable and good quality communication route in order to avoid any unnecessary packet loss. Intuitively, if the chosen communication route is error-prone, it is very likely that the transmitted packets over consecutive links may get corrupted or even lost. It is well-known that retransmissions incur additional delay and increase the overhead in the network. This is very undesirable for delay sensitive applications, especially in an ad hoc wireless network environment where devices are typically power-limited and topology is constantly changing. Unlike most of the existing routing protocols for ad hoc wireless networks, in which the basic criterion for route selection is the minimization of the overall route length, in this paper we consider bit error rate (BER)-based routing, where the chosen route is the one which guarantees the lowest BER at the ending node. In other words, we consider providing QoS in terms of BER at the destination node. Our analysis shows that, according to this criterion, shortest path (SP) routing is not always the optimal choice as it often selects a path with unacceptable BER which can directly affect the end-to-end packet delay and goodput.
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paper_title: Maximum Battery Life Routing to Support Ubiquitous Mobile Computing in Wireless Ad Hoc Networks

paper_content:

Most ad hoc mobile devices today operate on batteries. Hence, power consumption becomes an important issue. To maximize the lifetime of ad hoc mobile networks, the power consumption rate of each node must be evenly distributed, and the overall transmission power for each connection request must be minimized. These two objectives cannot be satisfied simultaneously by employing routing algorithms proposed in previous work. We present a new power-aware routing protocol to satisfy these two constraints simultaneously; we also compare the performance of different types of power-related routing algorithms via simulation. Simulation results confirm the need to strike a balance in attaining service availability performance of the whole network vs. the lifetime of ad hoc mobile devices.
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paper_title: Power-aware routing in mobile ad hoc networks

paper_content:

b this paper we present a case for using new power-aware metn.cs for determining routes in wireless ad hoc networks. We present five ~erent metriw based on battery power consumption at nodw. We show that using th=e metrics in a shortest-cost routing algorithm reduces the cost/packet of routing packets by 5-30% over shortwt-hop routing (this cost reduction is on top of a 40-70% reduction in energy consumption obtained by using PAMAS, our MAC layer prtocol). Furthermore, using these new metrics ensures that the mean time to node failure is increased si~cantly. An interesting property of using shortest-cost routing is that packet delays do not increase. Fintiy, we note that our new metrim can be used in most tradition routing protocols for ad hoc networks.
---
paper_title: Power-aware routing in mobile ad hoc networks

paper_content:

b this paper we present a case for using new power-aware metn.cs for determining routes in wireless ad hoc networks. We present five ~erent metriw based on battery power consumption at nodw. We show that using th=e metrics in a shortest-cost routing algorithm reduces the cost/packet of routing packets by 5-30% over shortwt-hop routing (this cost reduction is on top of a 40-70% reduction in energy consumption obtained by using PAMAS, our MAC layer prtocol). Furthermore, using these new metrics ensures that the mean time to node failure is increased si~cantly. An interesting property of using shortest-cost routing is that packet delays do not increase. Fintiy, we note that our new metrim can be used in most tradition routing protocols for ad hoc networks.
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paper_title: Energy conserving routing in wireless ad-hoc networks

paper_content:

An ad-hoc network of wireless static nodes is considered as it arises in a rapidly deployed, sensor-based, monitoring system. Information is generated in certain nodes and needs to reach a set of designated gateway nodes. Each node may adjust its power within a certain range that determines the set of possible one hop away neighbors. Traffic forwarding through multiple hops is employed when the intended destination is not within immediate reach. The nodes have limited initial amounts of energy that is consumed at different rates depending on the power level and the intended receiver. We propose algorithms to select the routes and the corresponding power levels such that the time until the batteries of the nodes drain-out is maximized. The algorithms are local and amenable to distributed implementation. When there is a single power level, the problem is reduced to a maximum flow problem with node capacities and the algorithms converge to the optimal solution. When there are multiple power levels then the achievable lifetime is close to the optimal (that is computed by linear programming) most of the time. It turns out that in order to maximize the lifetime, the traffic should be routed such that the energy consumption is balanced among the nodes in proportion to their energy reserves, instead of routing to minimize the absolute consumed power.
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paper_title: Energy Efficient Routing Protocols for Mobile Ad Hoc Networks

paper_content:

Summary Although establishing correct and efficient routes is an important design issue in mobile ad hoc networks (MANETs), a more challenging goal is to provide energy efficient routes because mobile nodes’ operation time is the most critical limiting factor. This article surveys and classifies the energy-aware routing protocols proposed for MANETs. They minimize either the active communication energy required to transmit or receive packets or the inactive energy consumed when a mobile node stays idle but listens to the wireless medium for any possible communication requests from other nodes. Transmission power control approach and load distribution approach belong to the former category, and sleep/power-down mode approach belongs to the latter category. While it is not clear whether any particular algorithm or a class of algorithms is the best for all scenarios, each protocol has definite advantages/disadvantages and is well suited for certain situations. The purpose of this paper is to facilitate the research efforts in combining the existing solutions to offer a more energy efficient routing mechanism. Copyright # 2003 John Wiley & Sons, Ltd.
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paper_title: An on-demand minimum energy routing protocol for a wireless ad hoc network

paper_content:

A minimum energy routing protocol reduces the energy consumption of the nodes in a wireless ad hoc network by routing packets on routes that consume the minimum amount of energy to get the packets to their destination. This paper identifies the necessary features of an on-demand minimum energy routing protocol and suggests mechanisms for their implementation. We highlight the importance of efficient caching techniques to store the minimum energy route information and propose the use of an 'energy aware' link cache for storing this information. We compare the performance of an on-demand minimum energy routing protocol in terms of energy savings with an existing on-demand ad hoc routing protocol via simulation. We discuss the implementation of Dynamic Source Routing (DSR) protocol using the Click modular router on a real life test-bed consisting of laptops and wireless Ethernet cards. Finally we describe the modifications we have made to the DSR router to make it energy aware.
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paper_title: Energy Efficient Routing Protocols for Mobile Ad Hoc Networks

paper_content:

Summary Although establishing correct and efficient routes is an important design issue in mobile ad hoc networks (MANETs), a more challenging goal is to provide energy efficient routes because mobile nodes’ operation time is the most critical limiting factor. This article surveys and classifies the energy-aware routing protocols proposed for MANETs. They minimize either the active communication energy required to transmit or receive packets or the inactive energy consumed when a mobile node stays idle but listens to the wireless medium for any possible communication requests from other nodes. Transmission power control approach and load distribution approach belong to the former category, and sleep/power-down mode approach belongs to the latter category. While it is not clear whether any particular algorithm or a class of algorithms is the best for all scenarios, each protocol has definite advantages/disadvantages and is well suited for certain situations. The purpose of this paper is to facilitate the research efforts in combining the existing solutions to offer a more energy efficient routing mechanism. Copyright # 2003 John Wiley & Sons, Ltd.
---
paper_title: Power-aware routing in mobile ad hoc networks

paper_content:

b this paper we present a case for using new power-aware metn.cs for determining routes in wireless ad hoc networks. We present five ~erent metriw based on battery power consumption at nodw. We show that using th=e metrics in a shortest-cost routing algorithm reduces the cost/packet of routing packets by 5-30% over shortwt-hop routing (this cost reduction is on top of a 40-70% reduction in energy consumption obtained by using PAMAS, our MAC layer prtocol). Furthermore, using these new metrics ensures that the mean time to node failure is increased si~cantly. An interesting property of using shortest-cost routing is that packet delays do not increase. Fintiy, we note that our new metrim can be used in most tradition routing protocols for ad hoc networks.
---
paper_title: Distributed Quality-of-Service Routing in Ad Hoc Networks

paper_content:

In an ad hoc network, all communication is done over wireless media, typically by radio through the air, without the help of wired base stations. Since direct communication is allowed only between adjacent nodes, distant nodes communicate over multiple hops. The quality-of-service (QoS) routing in an ad hoc network is difficult because the network topology may change constantly, and the available state information for routing is inherently imprecise. In this paper, we propose a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the most qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave the network. Our algorithms consider not only the QoS requirement, but also the cost optimality of the routing path to improve the overall network performance. Extensive simulations show that high call admission ratio and low-cost paths are achieved with modest routing overhead. The algorithms can tolerate a high degree of information imprecision.
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paper_title: QoS routing for wireless ad hoc networks: problems, algorithms, and protocols

paper_content:

QoS routing plays an important role for providing QoS in wireless ad hoc networks. The goals of QoS routing are in general twofold: selecting routes with satisfied QoS requirement(s), and achieving global efficiency in resource utilization. In this article we first discuss some key design considerations in providing QoS routing support, and present a review of previous work addressing the issue of route selection subject to QoS constraint(s). We then devise an on-demand delay-constrained unicast routing protocol. Various strategies are employed in the protocol to reduce the communication overhead in acquiring cost-effective delay-constrained routes. Simulation results are used to verify our expectation of the high performance of the devised protocol. Finally, we discuss some possible future directions for providing efficient QoS routing support in wireless ad hoc networks.
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paper_title: Mobility increases the capacity of ad-hoc wireless networks

paper_content:

The capacity of ad hoc wireless networks is constrained by the mutual interference of concurrent transmissions between nodes. We study a model of an ad hoc network where n nodes communicate in random source-destination pairs. These nodes are assumed to be mobile. We examine the per-session throughput for applications with loose delay constraints, such that the topology changes over the time-scale of packet delivery. Under this assumption, the per-user throughput can increase dramatically when nodes are mobile rather than fixed. This improvement can be achieved by exploiting a form of multiuser diversity via packet relaying.
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paper_title: A paradigm for quality-of-service in wireless ad hoc networks using synchronous signaling and node states

paper_content:

Most limitations in mechanisms geared at achieving quality-of-service (QoS) in wireless ad hoc networking can be traced to solutions based on mapping wireless networks to a wireline paradigm of nodes and links. We contend that this paradigm is not appropriate since links are not physical entities and do not accurately represent the radio frequency (RF) media. Using the link abstraction makes arbitration of the use of the RF media cumbersome leaving only overprovisioning techniques to deliver QoS. In this paper, we argue that an appropriate paradigm should match the physics of the network. The critical resource is electromagnetic spectrum in a space; in turn, this results in a complex paradigm since the part of the spectrum-space that each node wants to use is unique to that node and its destination and will overlap with parts that other nodes may want to use creating interdependences among nodes. This paper describes protocol approaches for access and routing that seek solutions within this wireless paradigm. Access is arbitrated using synchronous signaling and topology is resolved through the dissemination of node states. This approach provides an intuitive framework that provides mechanisms that can be exploited to arbitrate RF media use and implement traffic engineering techniques to deliver QoS. Our proposed approach provides a novel way of tracking the state of the network that can serve as a unified state dissemination mechanism to simultaneously support routing, multicasting, and most QoS heuristics.
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paper_title: Routing in ad hoc networks: a case for long hops

paper_content:

For multihop wireless networks, a fundamental question is whether it is advantageous to route over many short hops (short-hop routing) or over a smaller number of longer hops (long-hop routing). Short-hop routing has gained a lot of support, and its proponents mainly produce two arguments: reduced energy consumption and higher signal-to-interference ratios. Both arguments stem from a simplified analysis based on crude channel models that neglects delay, end-to-end reliability, bias power consumption, the impact of channel coding, mobility, and routing overhead. In this article we shed more light on these issues by listing 18 reasons why short-hop routing is not as beneficial as it seems to be. We also provide experimental evidence to support this claim. The conclusion is that for many networks, long-hop routing is in every aspect a very competitive strategy.
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paper_title: Analytical evaluation of a tradeoff between energy efficiency and responsiveness of neighbor discovery in self-organizing ad hoc networks

paper_content:

Ad hoc networking enables novel communication paradigms which require the definition of new quality-of-service (QoS) parameters and frameworks for QoS support. The relevant QoS requirements are frequently antagonist and, consequently, an appropriate tradeoff has to be determined and achieved to fit all of them. As an example, the spontaneous networking featured by self-organizing ad hoc networks is possible only if neighboring communication nodes discover each other within a short period of time; however, velocity of discovery is paid in terms of energy consumption. In this paper, an analytical framework is derived which allows an evaluation of the tradeoff between energy efficiency and responsiveness in the discovery process. More specifically, the analytical framework allows either to achieve the highest velocity in the discovery process, given that the energy consumption is lower than a certain threshold, or to minimize the energy consumption given that specific requirements in terms of the discovery velocity are satisfied. The analytical framework is applied to significant case studies to derive design implications on neighbor discovery algorithms.
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paper_title: Distributed Quality-of-Service Routing in Ad Hoc Networks

paper_content:

In an ad hoc network, all communication is done over wireless media, typically by radio through the air, without the help of wired base stations. Since direct communication is allowed only between adjacent nodes, distant nodes communicate over multiple hops. The quality-of-service (QoS) routing in an ad hoc network is difficult because the network topology may change constantly, and the available state information for routing is inherently imprecise. In this paper, we propose a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the most qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave the network. Our algorithms consider not only the QoS requirement, but also the cost optimality of the routing path to improve the overall network performance. Extensive simulations show that high call admission ratio and low-cost paths are achieved with modest routing overhead. The algorithms can tolerate a high degree of information imprecision.
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paper_title: Routing protocol with QoS guarantees for ad-hoc network

paper_content:

A novel routing protocol for ad-hoc networks, delay sensitive adaptive routing protocol (DSARP), is presented, which not only provides a reliable route for delay-sensitive traffic, but also can select the route based on the constrained condition: ‘the shortest route and the lowest average delay’. Therefore, the DSARP is assured to provide QoS guarantee and improve the performance of the network. Simulation results show that DSARP outperforms the dynamic source routing protocol used in ad-hoc wireless networks.
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paper_title: On-demand SIR and bandwidth-guaranteed routing with transmit power assignment in ad hoc mobile networks

paper_content:

In this paper, we propose a novel on-demand quality-of-service (QoS) routing protocol, SBR [signal-to-interference (SIR) and bandwidth routing], which explicitly fulfills both SIR and bandwidth requirements from different multimedia users in ad hoc mobile networks. With SBR, bandwidth reservation is made by allocating time slots and SIR reservation is ensured by assigning adequate powers at the intermediate nodes between a source and a destination. The power-assignment method used in SBR supports finding routes that satisfy the SIR requirements as well as reduces the level of prevailing interference that necessarily occurs in multiple-access wireless networks. SBR also has a new backup capability of establishing multiple paths, even for a single connection, when the route search cannot find a single path that supports the QoS requirements, which contributes to reducing the probability of call denials in constructing the route due to a lack of suitable paths. Extensive simulations show that SBR significantly reduces the ratio of unsuccessful calls with modest routing overhead.
---
paper_title: QoS routing using lower layer information in ad hoc networks

paper_content:

A wireless ad hoc network is an autonomous system where all nodes are capable of movement and can be connected dynamically in an arbitrary manner. Without a network infrastructure, network nodes function as routers which discover and maintain routes to other nodes in the network. Routing in ad hoc networks has received a lot of attention due to the challenges posed by the self-organizing nature of the network, the dynamic topology, and the unreliable wireless medium. Quality of service (QoS) routing searches for routes with sufficient resources for the QoS requirements and is one of the core technologies to support QoS for real-time multimedia and data applications in ad hoc networks. We show that MAC layer information can be utilized at the routing layer via certain routing metrics for optimal route selection. We propose to use MAC delay as an indication of the level of interference of a link. Link reliability and residual bandwidth are two other routing constraints. Then, the resulting NP-complete multiple constraint routing problem is solved using a heuristic algorithm. The performance of the algorithm is studied using simulations.
---
paper_title: QoS routing for wireless ad hoc networks: problems, algorithms, and protocols

paper_content:

QoS routing plays an important role for providing QoS in wireless ad hoc networks. The goals of QoS routing are in general twofold: selecting routes with satisfied QoS requirement(s), and achieving global efficiency in resource utilization. In this article we first discuss some key design considerations in providing QoS routing support, and present a review of previous work addressing the issue of route selection subject to QoS constraint(s). We then devise an on-demand delay-constrained unicast routing protocol. Various strategies are employed in the protocol to reduce the communication overhead in acquiring cost-effective delay-constrained routes. Simulation results are used to verify our expectation of the high performance of the devised protocol. Finally, we discuss some possible future directions for providing efficient QoS routing support in wireless ad hoc networks.
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paper_title: A Distributed Entropy-Based Long-Life QoS Routing Algorithm in Ad Hoc Network

paper_content:

On the basis of analyzing the problem of unicasting QoS routing in Ad Hoc networks, a new distributed QoS routing algorithm in the Ad Hoc network— EBLLD (entropy-based long-life distributed QoS routing) algorithm, is proposed. The key idea of EBLLD algorithm is to construct the new metric-entropy and select the long-life path with the help of entropy metric to reduce the number of route reconstruction so as to provide QoS guarantee in the Ad Hoc network whose topology changes continuously. The EBLLD algorithm uses the local multicast mechanism, orders and sorts the outgoing link with the heuristic function and entropy metric to reduce the message overhead. The simulation shows that the EBLLD algorithm can acquire a higher routing success ratio with the low message overhead. In addition, the EBLLD algorithm is scalable and applicable to large-scale Ad Hoc network.
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paper_title: Link stability models for QoS ad hoc routing algorithms

paper_content:

In an ad hoc network, the topology varies as a result of the mobility of its mobile hosts. Consequently, the task of performing ad hoc network routing is more complex and less efficient. Many ad hoc network routing protocols have been proposed. However, more work is required in developing scalable ad hoc routing protocols that support quality-of-service (QoS). Recently, our study shows that link stability (in term of link survival time) has great impact on QoS performance of routing in ad hoc networks. We developed a number of models which effectively estimate link stability for different network movement patterns. By implementing link stability, which is a standalone network parameter, the QoS performance of varieties of ad hoc routing algorithms could be improved when networks are subjected to topological changes, to variations in traffic loading patterns (including a multitude of traffic classes). In this paper, we show that QoS performance of AODV is improved by implementing link stability parameter.
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paper_title: QoS routing performance in multihop, multimedia, wireless networks

paper_content:

We propose an approach to QoS (quality of service) routing in a multimedia, multihop, wireless network. The wireless net can be either stand alone, or connected to the wired net. The main focus of the paper is the QoS routing procedure which can inform the source of the bandwidth and quality of service available to any destination in the wireless network. This knowledge enables the establishment of QoS connections within the wireless network and the efficient support of real time, multimedia traffic. In addition, it enables more effective call acceptance control. In the case of an ATM interconnection, QoS information permits one to extend the ATM virtual circuit service to the wireless network, with possible renegotiation of QoS parameters at the gateway. Simulation experiments show the efficiency of QoS routing in selected multihop, mobile radio network scenarios.
---
paper_title: A QoS routing method for ad-hoc networks based on genetic algorithm

paper_content:

A lot of work has been done on routing in MANETs. However, the proposed routing resolutions deal only with the best effort data traffic. Connections with quality of service (QoS) requirements are not supported. QoS routing has been receiving increasingly intensive attention in the wireline network domain. However, for MANETs only few QoS algorithms are proposed to be developed and QoS routing algorithms should be adaptive, flexible, and intelligent. We propose a genetic algorithm (GA) based routing method for Mobile Ad-Hoc Networks (GAMAN). Robustness rather that optimality is the primary concern of GAMAN. The GAMAN uses two QoS parameters for routing. The performance evaluation via simulations shows that GAMAN is a promising QoS routing algorithm for MANETs.
---
paper_title: QoS routing in ad hoc wireless networks

paper_content:

The emergence of nomadic applications have generated a lot of interest in wireless network infrastructures which support multimedia services. We propose a bandwidth routing algorithm for multimedia support in a multihop wireless network. This network can be interconnected to wired networks (e.g. ATM or the Internet) or stand alone. Our bandwidth routing includes bandwidth calculation and reservation schemes. Under such a routing algorithm, we can derive a route to satisfy the bandwidth requirement for the QoS constraint. At a source node, the bandwidth information can be used to decide to accept a new call or not immediately. This is specially important to carry out a fast handoff when interconnecting to an ATM backbone infrastructure. It enables an efficient call admission control. The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network. Different types of QoS traffic can be integrated in such a dynamic radio network with high performance.
---
paper_title: Interference-aware QoS routing (IQRouting) for ad-hoc networks

paper_content:

Traditional distributed algorithms for QoS routing in wired networks may not work in the ad-hoc domain, due to interference between links. We propose a heuristic interference-aware QoS routing algorithm (IQRouting) that chooses candidate paths based on localized information at the source nodes. The candidate paths are compared in a distributed manner using probe packets, with the best path confirmed by the destination node. Simulations demonstrate significant (up to 30 %) improvements in admission ratio over traditional shortest path algorithms, and better performance than other QoS routing algorithms in literature as well
---
paper_title: QoS-aware routing based on bandwidth estimation for mobile ad hoc networks

paper_content:

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support.
---
paper_title: A position-based QoS routing scheme for UWB mobile ad hoc networks

paper_content:

Ultra-wideband (UWB) wireless communication is a promising spread-spectrum technology that supports very high data rates and provides precise position information of mobile users. In this paper, we present a position-based quality-of-service (QoS) routing scheme for UWB mobile ad hoc networks. The scheme applies call admission control and temporary bandwidth reservation for discovered routes, taking into consideration the medium access control interactions. Via cross-layer design, it exploits UWB advantages at the network layer by using the position information in routing and bandwidth reservation and by supporting the multirate capability. Simulation results demonstrate that the proposed routing scheme is effective in end-to-end QoS support.
---
paper_title: Contention-aware admission control for ad hoc networks

paper_content:

An admission control algorithm must coordinate between flows to provide guarantees about how the medium is shared. In wired networks, nodes can monitor the medium to see how much bandwidth is being used. However, in ad hoc networks, communication from one node may consume the bandwidth of neighboring nodes. Therefore, the bandwidth consumption of flows and the available resources to a node are not local concepts, but related to the neighboring nodes in carrier-sensing range. Current solutions do not address how to perform admission control in such an environment so that the admitted flows in the network do not exceed network capacity. In this paper, we present a scalable and efficient admission control framework - contention-aware admission control protocol (CACP) - to support QoS in ad hoc networks. We present several options for the design of CACP and compare the performance of these options using both mathematical analysis and simulation results. We also demonstrate the effectiveness of CACP compared to existing approaches through extensive simulations.
---
paper_title: An application-aware qos routing scheme with improved stability for multimedia applications in mobile ad hoc networks

paper_content:

Both delay and bandwidth are the crucial node state information considered in QoS routing schemes for multimedia applications in mobile Ad Hoc networks. In this paper, we propose an application-aware QoS routing scheme for multimedia applications in mobile Ad Hoc networks. In our scheme, the real time control protocol (RTCP) is used to estimate the node state instead of the additional probing messages, and an optimally stable route can be established according to QoS requirements of the multimedia application based on the node state information. It has been shown that the routing performance is improved significantly compared to the existing schemes using the additional probing messages.
---
paper_title: QOLSR, QoS routing for ad hoc wireless networks using OLSR

paper_content:

This paper describes a novel quality-of-service (QoS) routing protocol for ad hoc networks based on the OLSR protocol. Our protocol, QOLSR, is designed for wireless networks with stationary or moving nodes, where each node is equipped with 802.11 wireless card. The goal of our protocol is not only to find a route from a source to a destination, but an optimal route that satisfies the end-to-end QoS requirement, often given in terms of bandwidth or delay. We present an analytical model to compute the average delay and permissible throughput on links using the IEEE 802.11 medium access protocol and considering correlations and interferences between nodes. This model takes into account packet's collision probability, node's MAC queuing and service times based on the IEEE 802.11 binary exponential backoff algorithm and the events underneath its operation. Afterwards, our protocol assigns weights to individual links based on the average delay and bandwidth metrics of packets over the link. We present a distributed algorithm for multiple QoS requirements to find the source destination optimal paths in terms of bandwidth and delay using the known partial network topology available on each node. However, these optimal paths in partial network topology are not optimal paths in the whole ad hoc network. We show that this problem is due to the heuristic for the selection of MPRs used in OLSR. We propose innovative heuristics for the selection of MPRs based on QoS measurements that allow QOLSR to find optimal paths on the known partial topology having the same bandwidth performances that those on the whole network. The performance evaluation of our protocol in both static and dynamic ad hoc networks is extensively investigated. Mathematical analysis and simulation results show that the QOLSR protocol yields better performance compared to the best-effort OLSR protocol and significantly improves throughput by using our proposed heuristic. Copyright © 2005 AEIT.
---
paper_title: A paradigm for quality-of-service in wireless ad hoc networks using synchronous signaling and node states

paper_content:

Most limitations in mechanisms geared at achieving quality-of-service (QoS) in wireless ad hoc networking can be traced to solutions based on mapping wireless networks to a wireline paradigm of nodes and links. We contend that this paradigm is not appropriate since links are not physical entities and do not accurately represent the radio frequency (RF) media. Using the link abstraction makes arbitration of the use of the RF media cumbersome leaving only overprovisioning techniques to deliver QoS. In this paper, we argue that an appropriate paradigm should match the physics of the network. The critical resource is electromagnetic spectrum in a space; in turn, this results in a complex paradigm since the part of the spectrum-space that each node wants to use is unique to that node and its destination and will overlap with parts that other nodes may want to use creating interdependences among nodes. This paper describes protocol approaches for access and routing that seek solutions within this wireless paradigm. Access is arbitrated using synchronous signaling and topology is resolved through the dissemination of node states. This approach provides an intuitive framework that provides mechanisms that can be exploited to arbitrate RF media use and implement traffic engineering techniques to deliver QoS. Our proposed approach provides a novel way of tracking the state of the network that can serve as a unified state dissemination mechanism to simultaneously support routing, multicasting, and most QoS heuristics.
---
paper_title: CEDAR: a core-extraction distributed ad hoc routing algorithm

paper_content:

CEDAR is an algorithm for QoS routing in ad hoc network environments. It has three key components: (a) the establishment and maintenance of a self-organizing routing infrastructure called the core for performing route computations, (b) the propagation of the link-state of stable high-bandwidth links in the core through increase/decrease waves, and (c) a QoS route computation algorithm that is executed at the core nodes using only locally available state. But preliminary performance evaluation shows that CEDAR is a robust and adaptive QoS routing algorithm that reacts effectively to the dynamics of the network while still approximating link-state performance for stable networks.
---
paper_title: QoS routing performance in multihop, multimedia, wireless networks

paper_content:

We propose an approach to QoS (quality of service) routing in a multimedia, multihop, wireless network. The wireless net can be either stand alone, or connected to the wired net. The main focus of the paper is the QoS routing procedure which can inform the source of the bandwidth and quality of service available to any destination in the wireless network. This knowledge enables the establishment of QoS connections within the wireless network and the efficient support of real time, multimedia traffic. In addition, it enables more effective call acceptance control. In the case of an ATM interconnection, QoS information permits one to extend the ATM virtual circuit service to the wireless network, with possible renegotiation of QoS parameters at the gateway. Simulation experiments show the efficiency of QoS routing in selected multihop, mobile radio network scenarios.
---
paper_title: QoS routing in ad hoc wireless networks

paper_content:

The emergence of nomadic applications have generated a lot of interest in wireless network infrastructures which support multimedia services. We propose a bandwidth routing algorithm for multimedia support in a multihop wireless network. This network can be interconnected to wired networks (e.g. ATM or the Internet) or stand alone. Our bandwidth routing includes bandwidth calculation and reservation schemes. Under such a routing algorithm, we can derive a route to satisfy the bandwidth requirement for the QoS constraint. At a source node, the bandwidth information can be used to decide to accept a new call or not immediately. This is specially important to carry out a fast handoff when interconnecting to an ATM backbone infrastructure. It enables an efficient call admission control. The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network. Different types of QoS traffic can be integrated in such a dynamic radio network with high performance.
---
paper_title: Highly dynamic Destination-Sequenced Distance-Vector routing (DSDV) for mobile computers

paper_content:

An ad-hoc network is the cooperative engagement of a collection of Mobile Hosts without the required intervention of any centralized Access Point. In this paper we present an innovative design for the operation of such ad-hoc networks. The basic idea of the design is to operate each Mobile Host as a specialized router, which periodically advertises its view of the interconnection topology with other Mobile Hosts within the network. This amounts to a new sort of routing protocol. We have investigated modifications to the basic Bellman-Ford routing mechanisms, as specified by RIP [5], to make it suitable for a dynamic and self-starting network mechanism as is required by users wishing to utilize ad hoc networks. Our modifications address some of the previous objections to the use of Bellman-Ford, related to the poor looping properties of such algorithms in the face of broken links and the resulting time dependent nature of the interconnection topology describing the links between the Mobile Hosts. Finally, we describe the ways in which the basic network-layer routing can be modified to provide MAC-layer support for ad-hoc networks.
---
paper_title: Contention-aware admission control for ad hoc networks

paper_content:

An admission control algorithm must coordinate between flows to provide guarantees about how the medium is shared. In wired networks, nodes can monitor the medium to see how much bandwidth is being used. However, in ad hoc networks, communication from one node may consume the bandwidth of neighboring nodes. Therefore, the bandwidth consumption of flows and the available resources to a node are not local concepts, but related to the neighboring nodes in carrier-sensing range. Current solutions do not address how to perform admission control in such an environment so that the admitted flows in the network do not exceed network capacity. In this paper, we present a scalable and efficient admission control framework - contention-aware admission control protocol (CACP) - to support QoS in ad hoc networks. We present several options for the design of CACP and compare the performance of these options using both mathematical analysis and simulation results. We also demonstrate the effectiveness of CACP compared to existing approaches through extensive simulations.
---
paper_title: Distributed Quality-of-Service Routing in Ad Hoc Networks

paper_content:

In an ad hoc network, all communication is done over wireless media, typically by radio through the air, without the help of wired base stations. Since direct communication is allowed only between adjacent nodes, distant nodes communicate over multiple hops. The quality-of-service (QoS) routing in an ad hoc network is difficult because the network topology may change constantly, and the available state information for routing is inherently imprecise. In this paper, we propose a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the most qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave the network. Our algorithms consider not only the QoS requirement, but also the cost optimality of the routing path to improve the overall network performance. Extensive simulations show that high call admission ratio and low-cost paths are achieved with modest routing overhead. The algorithms can tolerate a high degree of information imprecision.
---
paper_title: Highly dynamic Destination-Sequenced Distance-Vector routing (DSDV) for mobile computers

paper_content:

An ad-hoc network is the cooperative engagement of a collection of Mobile Hosts without the required intervention of any centralized Access Point. In this paper we present an innovative design for the operation of such ad-hoc networks. The basic idea of the design is to operate each Mobile Host as a specialized router, which periodically advertises its view of the interconnection topology with other Mobile Hosts within the network. This amounts to a new sort of routing protocol. We have investigated modifications to the basic Bellman-Ford routing mechanisms, as specified by RIP [5], to make it suitable for a dynamic and self-starting network mechanism as is required by users wishing to utilize ad hoc networks. Our modifications address some of the previous objections to the use of Bellman-Ford, related to the poor looping properties of such algorithms in the face of broken links and the resulting time dependent nature of the interconnection topology describing the links between the Mobile Hosts. Finally, we describe the ways in which the basic network-layer routing can be modified to provide MAC-layer support for ad-hoc networks.
---
paper_title: On-demand SIR and bandwidth-guaranteed routing with transmit power assignment in ad hoc mobile networks

paper_content:

In this paper, we propose a novel on-demand quality-of-service (QoS) routing protocol, SBR [signal-to-interference (SIR) and bandwidth routing], which explicitly fulfills both SIR and bandwidth requirements from different multimedia users in ad hoc mobile networks. With SBR, bandwidth reservation is made by allocating time slots and SIR reservation is ensured by assigning adequate powers at the intermediate nodes between a source and a destination. The power-assignment method used in SBR supports finding routes that satisfy the SIR requirements as well as reduces the level of prevailing interference that necessarily occurs in multiple-access wireless networks. SBR also has a new backup capability of establishing multiple paths, even for a single connection, when the route search cannot find a single path that supports the QoS requirements, which contributes to reducing the probability of call denials in constructing the route due to a lack of suitable paths. Extensive simulations show that SBR significantly reduces the ratio of unsuccessful calls with modest routing overhead.
---
paper_title: Routing Support for Providing Guaranteed End-To-End Quality-Of-Service

paper_content:

The up-coming Gbps high-speed networks are expected to support a wide range of real-time, communication-intensive applications. The quality-of-service (QoS) requirements for the timely delivery of multimedia information raise new challenges for the development of integrated-service broadband networks. One of the key issues is QoS routing, which allows selecting network routes with sufficient resources for requested QoS parameters. The goal of QoS routing solutions is two-fold: satisfying the QoS requirements for every admitted connection and achieving global efficiency in resource utilization. ::: Many unicast/multicast QoS routing algorithms were published recently. However, there still exist a lot of unsolved problems in this area. A few examples are listed as follows. (1) There lacks a simple solution with predictable performance and adjustable overhead for the NP-complete multi-constraint routing problem. (2) All existing algorithms are tailored towards specific problems, and there lacks a simple, general routing framework which can be easily extended to handle new problems. (3) Most routing algorithms assume the availability of precise state information about the network, which however is impractical in the real world. ::: We address the above problems, and the goal of this dissertation is to provide simple, general and extensible solutions for QoS routing. We study different routing strategies, compare them and outline the challenges. We propose various algorithms based on different network state models, evaluate these algorithms by analysis and simulation, discuss their strengths and weaknesses of different routing strategies, and compare them with the existing algorithms. The major achievement of this dissertation is outlined in the following. (1) A heuristic approach is proposed to solve the multi-constraint routing problem. It allows the dynamic tradeoff between performance and overhead. (2) A distributed routing framework is proposed to integrate a family of routing algorithms which support applications with QoS requirements on bandwidth, delay, delay jitter, cost, path length, and their combination. (3) Source and distributed routing algorithms axe proposed to work with state information which has a high degree of imprecision. (4) Distributed QoS routing algorithms are proposed for mobile ad-hoc networks whose topologies change as nodes move, join, or leave the networks. (5) An integrated framework is proposed to support routing and scheduling of co-existing QoS and best-effort flows.
---
paper_title: Conditions that impact the complexity of QoS routing

paper_content:

Finding a path in a network based on multiple constraints (the MCP problem) is often considered an integral part of quality of service (QoS) routing. QoS routing with constraints on multiple additive measures has been proven to be NP-complete. This proof has dramatically influenced the research community, resulting into the common belief that exact QoS routing is intractable in practice. However, to our knowledge, no one has ever examined which "worst cases" lead to intractability. In fact, the MCP problem is not strong NP-complete, suggesting that in practice an exact QoS routing algorithm may work in polynomial time. The goal of this paper is to argue that in practice QoS routing may be tractable. We will provide properties, an approximate analysis, and simulation results to indicate that NP-completeness hinges on four conditions, namely: 1) the topology; 2) the granularity of link weights; 3) the correlation between link weights; and 4) the constraints. We expect that, in practice, these conditions are manageable and therefore believe that exact QoS routing is tractable in practice.
---
paper_title: A paradigm for quality-of-service in wireless ad hoc networks using synchronous signaling and node states

paper_content:

Most limitations in mechanisms geared at achieving quality-of-service (QoS) in wireless ad hoc networking can be traced to solutions based on mapping wireless networks to a wireline paradigm of nodes and links. We contend that this paradigm is not appropriate since links are not physical entities and do not accurately represent the radio frequency (RF) media. Using the link abstraction makes arbitration of the use of the RF media cumbersome leaving only overprovisioning techniques to deliver QoS. In this paper, we argue that an appropriate paradigm should match the physics of the network. The critical resource is electromagnetic spectrum in a space; in turn, this results in a complex paradigm since the part of the spectrum-space that each node wants to use is unique to that node and its destination and will overlap with parts that other nodes may want to use creating interdependences among nodes. This paper describes protocol approaches for access and routing that seek solutions within this wireless paradigm. Access is arbitrated using synchronous signaling and topology is resolved through the dissemination of node states. This approach provides an intuitive framework that provides mechanisms that can be exploited to arbitrate RF media use and implement traffic engineering techniques to deliver QoS. Our proposed approach provides a novel way of tracking the state of the network that can serve as a unified state dissemination mechanism to simultaneously support routing, multicasting, and most QoS heuristics.
---
paper_title: A paradigm for quality-of-service in wireless ad hoc networks using synchronous signaling and node states

paper_content:

Most limitations in mechanisms geared at achieving quality-of-service (QoS) in wireless ad hoc networking can be traced to solutions based on mapping wireless networks to a wireline paradigm of nodes and links. We contend that this paradigm is not appropriate since links are not physical entities and do not accurately represent the radio frequency (RF) media. Using the link abstraction makes arbitration of the use of the RF media cumbersome leaving only overprovisioning techniques to deliver QoS. In this paper, we argue that an appropriate paradigm should match the physics of the network. The critical resource is electromagnetic spectrum in a space; in turn, this results in a complex paradigm since the part of the spectrum-space that each node wants to use is unique to that node and its destination and will overlap with parts that other nodes may want to use creating interdependences among nodes. This paper describes protocol approaches for access and routing that seek solutions within this wireless paradigm. Access is arbitrated using synchronous signaling and topology is resolved through the dissemination of node states. This approach provides an intuitive framework that provides mechanisms that can be exploited to arbitrate RF media use and implement traffic engineering techniques to deliver QoS. Our proposed approach provides a novel way of tracking the state of the network that can serve as a unified state dissemination mechanism to simultaneously support routing, multicasting, and most QoS heuristics.
---
paper_title: CEDAR: a core-extraction distributed ad hoc routing algorithm

paper_content:

CEDAR is an algorithm for QoS routing in ad hoc network environments. It has three key components: (a) the establishment and maintenance of a self-organizing routing infrastructure called the core for performing route computations, (b) the propagation of the link-state of stable high-bandwidth links in the core through increase/decrease waves, and (c) a QoS route computation algorithm that is executed at the core nodes using only locally available state. But preliminary performance evaluation shows that CEDAR is a robust and adaptive QoS routing algorithm that reacts effectively to the dynamics of the network while still approximating link-state performance for stable networks.
---
paper_title: Interference-aware QoS routing (IQRouting) for ad-hoc networks

paper_content:

Traditional distributed algorithms for QoS routing in wired networks may not work in the ad-hoc domain, due to interference between links. We propose a heuristic interference-aware QoS routing algorithm (IQRouting) that chooses candidate paths based on localized information at the source nodes. The candidate paths are compared in a distributed manner using probe packets, with the best path confirmed by the destination node. Simulations demonstrate significant (up to 30 %) improvements in admission ratio over traditional shortest path algorithms, and better performance than other QoS routing algorithms in literature as well
---
paper_title: Ad-hoc on-demand distance vector routing

paper_content:

An ad-hoc network is the cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. We present Ad-hoc On Demand Distance Vector Routing (AODV), a novel algorithm for the operation of such ad-hoc networks. Each mobile host operates as a specialized router, and routes are obtained as needed (i.e., on-demand) with little or no reliance on periodic advertisements. Our new routing algorithm is quite suitable for a dynamic self starting network, as required by users wishing to utilize ad-hoc networks. AODV provides loop-free routes even while repairing broken links. Because the protocol does not require global periodic routing advertisements, the demand on the overall bandwidth available to the mobile nodes is substantially less than in those protocols that do necessitate such advertisements. Nevertheless we can still maintain most of the advantages of basic distance vector routing mechanisms. We show that our algorithm scales to large populations of mobile nodes wishing to form ad-hoc networks. We also include an evaluation methodology and simulation results to verify the operation of our algorithm.
---
paper_title: QoS-aware routing based on bandwidth estimation for mobile ad hoc networks

paper_content:

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support.
---
paper_title: Contention-aware admission control for ad hoc networks

paper_content:

An admission control algorithm must coordinate between flows to provide guarantees about how the medium is shared. In wired networks, nodes can monitor the medium to see how much bandwidth is being used. However, in ad hoc networks, communication from one node may consume the bandwidth of neighboring nodes. Therefore, the bandwidth consumption of flows and the available resources to a node are not local concepts, but related to the neighboring nodes in carrier-sensing range. Current solutions do not address how to perform admission control in such an environment so that the admitted flows in the network do not exceed network capacity. In this paper, we present a scalable and efficient admission control framework - contention-aware admission control protocol (CACP) - to support QoS in ad hoc networks. We present several options for the design of CACP and compare the performance of these options using both mathematical analysis and simulation results. We also demonstrate the effectiveness of CACP compared to existing approaches through extensive simulations.
---
paper_title: Quality of Service Routing and Admission Control for Mobile Ad-hoc Networks with a Contention-based MAC Layer

paper_content:

In mobile ad hoc networks (MANETs), accurate throughput-constrained Quality of Service (QoS) routing and admission control have proven difficult to achieve, mainly due to node mobility and contention for channel access. In this paper we propose a solution to those problems, utilising the Dynamic Source Routing (DSR) protocol for basic routing. Our design considers the throughput requirements of data sessions and how these are affected by protocol overheads and contention between nodes. Furthermore, in contrast to previous work, the time wasted at the MAC layer by collisions and channel access delays, is also considered. Simulation results show that in a stationary scenario with high offered load, and at the cost of increased routing overhead, our protocol more than doubles session completion rate (SCR) and reduces average packet delay by a factor of seven compared to classic DSR. Even in a highly mobile scenario, it can double SCR and cut average packet delay to a third.
---
paper_title: Improving Accuracy in Available Bandwidth Estimation for IEEE 802.11-based Ad Hoc Networks

paper_content:

In this article, we propose a method to enhance accuracy of the available bandwidth estimation in IEEE 802.11-based ad hoc networks. This method combines medium state monitoring, probability of collision estimation and backoff time evaluation, improving the method described in C. Sarr et al., (2005). We evaluate our solution by simulation on different scenarios and compare it with different QoS routing protocols based on different available bandwidth estimation techniques
---
paper_title: QoS routing using lower layer information in ad hoc networks

paper_content:

A wireless ad hoc network is an autonomous system where all nodes are capable of movement and can be connected dynamically in an arbitrary manner. Without a network infrastructure, network nodes function as routers which discover and maintain routes to other nodes in the network. Routing in ad hoc networks has received a lot of attention due to the challenges posed by the self-organizing nature of the network, the dynamic topology, and the unreliable wireless medium. Quality of service (QoS) routing searches for routes with sufficient resources for the QoS requirements and is one of the core technologies to support QoS for real-time multimedia and data applications in ad hoc networks. We show that MAC layer information can be utilized at the routing layer via certain routing metrics for optimal route selection. We propose to use MAC delay as an indication of the level of interference of a link. Link reliability and residual bandwidth are two other routing constraints. Then, the resulting NP-complete multiple constraint routing problem is solved using a heuristic algorithm. The performance of the algorithm is studied using simulations.
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paper_title: Routing Support for Providing Guaranteed End-To-End Quality-Of-Service

paper_content:

The up-coming Gbps high-speed networks are expected to support a wide range of real-time, communication-intensive applications. The quality-of-service (QoS) requirements for the timely delivery of multimedia information raise new challenges for the development of integrated-service broadband networks. One of the key issues is QoS routing, which allows selecting network routes with sufficient resources for requested QoS parameters. The goal of QoS routing solutions is two-fold: satisfying the QoS requirements for every admitted connection and achieving global efficiency in resource utilization. ::: Many unicast/multicast QoS routing algorithms were published recently. However, there still exist a lot of unsolved problems in this area. A few examples are listed as follows. (1) There lacks a simple solution with predictable performance and adjustable overhead for the NP-complete multi-constraint routing problem. (2) All existing algorithms are tailored towards specific problems, and there lacks a simple, general routing framework which can be easily extended to handle new problems. (3) Most routing algorithms assume the availability of precise state information about the network, which however is impractical in the real world. ::: We address the above problems, and the goal of this dissertation is to provide simple, general and extensible solutions for QoS routing. We study different routing strategies, compare them and outline the challenges. We propose various algorithms based on different network state models, evaluate these algorithms by analysis and simulation, discuss their strengths and weaknesses of different routing strategies, and compare them with the existing algorithms. The major achievement of this dissertation is outlined in the following. (1) A heuristic approach is proposed to solve the multi-constraint routing problem. It allows the dynamic tradeoff between performance and overhead. (2) A distributed routing framework is proposed to integrate a family of routing algorithms which support applications with QoS requirements on bandwidth, delay, delay jitter, cost, path length, and their combination. (3) Source and distributed routing algorithms axe proposed to work with state information which has a high degree of imprecision. (4) Distributed QoS routing algorithms are proposed for mobile ad-hoc networks whose topologies change as nodes move, join, or leave the networks. (5) An integrated framework is proposed to support routing and scheduling of co-existing QoS and best-effort flows.
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paper_title: QoS routing for wireless ad hoc networks: problems, algorithms, and protocols

paper_content:

QoS routing plays an important role for providing QoS in wireless ad hoc networks. The goals of QoS routing are in general twofold: selecting routes with satisfied QoS requirement(s), and achieving global efficiency in resource utilization. In this article we first discuss some key design considerations in providing QoS routing support, and present a review of previous work addressing the issue of route selection subject to QoS constraint(s). We then devise an on-demand delay-constrained unicast routing protocol. Various strategies are employed in the protocol to reduce the communication overhead in acquiring cost-effective delay-constrained routes. Simulation results are used to verify our expectation of the high performance of the devised protocol. Finally, we discuss some possible future directions for providing efficient QoS routing support in wireless ad hoc networks.
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paper_title: A position-based QoS routing scheme for UWB mobile ad hoc networks

paper_content:

Ultra-wideband (UWB) wireless communication is a promising spread-spectrum technology that supports very high data rates and provides precise position information of mobile users. In this paper, we present a position-based quality-of-service (QoS) routing scheme for UWB mobile ad hoc networks. The scheme applies call admission control and temporary bandwidth reservation for discovered routes, taking into consideration the medium access control interactions. Via cross-layer design, it exploits UWB advantages at the network layer by using the position information in routing and bandwidth reservation and by supporting the multirate capability. Simulation results demonstrate that the proposed routing scheme is effective in end-to-end QoS support.
---
paper_title: A position-based QoS routing scheme for UWB mobile ad hoc networks

paper_content:

Ultra-wideband (UWB) wireless communication is a promising spread-spectrum technology that supports very high data rates and provides precise position information of mobile users. In this paper, we present a position-based quality-of-service (QoS) routing scheme for UWB mobile ad hoc networks. The scheme applies call admission control and temporary bandwidth reservation for discovered routes, taking into consideration the medium access control interactions. Via cross-layer design, it exploits UWB advantages at the network layer by using the position information in routing and bandwidth reservation and by supporting the multirate capability. Simulation results demonstrate that the proposed routing scheme is effective in end-to-end QoS support.
---
paper_title: Contention-aware admission control for ad hoc networks

paper_content:

An admission control algorithm must coordinate between flows to provide guarantees about how the medium is shared. In wired networks, nodes can monitor the medium to see how much bandwidth is being used. However, in ad hoc networks, communication from one node may consume the bandwidth of neighboring nodes. Therefore, the bandwidth consumption of flows and the available resources to a node are not local concepts, but related to the neighboring nodes in carrier-sensing range. Current solutions do not address how to perform admission control in such an environment so that the admitted flows in the network do not exceed network capacity. In this paper, we present a scalable and efficient admission control framework - contention-aware admission control protocol (CACP) - to support QoS in ad hoc networks. We present several options for the design of CACP and compare the performance of these options using both mathematical analysis and simulation results. We also demonstrate the effectiveness of CACP compared to existing approaches through extensive simulations.
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paper_title: Optimized link state routing protocol for ad hoc networks

paper_content:

In this paper we propose and discuss an optimized link state routing protocol, named OLSR, for mobile wireless networks. The protocol is based on the link state algorithm and it is proactive (or table-driven) in nature. It employs periodic exchange of messages to maintain topology information of the network at each node. OLSR is an optimization over a pure link state protocol as it compacts the size of information sent in the messages, and furthermore, reduces the number of retransmissions to flood these messages in an entire network. For this purpose, the protocol uses the multipoint relaying technique to efficiently and economically flood its control messages. It provides optimal routes in terms of number of hops, which are immediately available when needed. The proposed protocol is best suitable for large and dense ad hoc networks.
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paper_title: QOLSR, QoS routing for ad hoc wireless networks using OLSR

paper_content:

This paper describes a novel quality-of-service (QoS) routing protocol for ad hoc networks based on the OLSR protocol. Our protocol, QOLSR, is designed for wireless networks with stationary or moving nodes, where each node is equipped with 802.11 wireless card. The goal of our protocol is not only to find a route from a source to a destination, but an optimal route that satisfies the end-to-end QoS requirement, often given in terms of bandwidth or delay. We present an analytical model to compute the average delay and permissible throughput on links using the IEEE 802.11 medium access protocol and considering correlations and interferences between nodes. This model takes into account packet's collision probability, node's MAC queuing and service times based on the IEEE 802.11 binary exponential backoff algorithm and the events underneath its operation. Afterwards, our protocol assigns weights to individual links based on the average delay and bandwidth metrics of packets over the link. We present a distributed algorithm for multiple QoS requirements to find the source destination optimal paths in terms of bandwidth and delay using the known partial network topology available on each node. However, these optimal paths in partial network topology are not optimal paths in the whole ad hoc network. We show that this problem is due to the heuristic for the selection of MPRs used in OLSR. We propose innovative heuristics for the selection of MPRs based on QoS measurements that allow QOLSR to find optimal paths on the known partial topology having the same bandwidth performances that those on the whole network. The performance evaluation of our protocol in both static and dynamic ad hoc networks is extensively investigated. Mathematical analysis and simulation results show that the QOLSR protocol yields better performance compared to the best-effort OLSR protocol and significantly improves throughput by using our proposed heuristic. Copyright © 2005 AEIT.
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paper_title: A Distributed Entropy-Based Long-Life QoS Routing Algorithm in Ad Hoc Network

paper_content:

On the basis of analyzing the problem of unicasting QoS routing in Ad Hoc networks, a new distributed QoS routing algorithm in the Ad Hoc network— EBLLD (entropy-based long-life distributed QoS routing) algorithm, is proposed. The key idea of EBLLD algorithm is to construct the new metric-entropy and select the long-life path with the help of entropy metric to reduce the number of route reconstruction so as to provide QoS guarantee in the Ad Hoc network whose topology changes continuously. The EBLLD algorithm uses the local multicast mechanism, orders and sorts the outgoing link with the heuristic function and entropy metric to reduce the message overhead. The simulation shows that the EBLLD algorithm can acquire a higher routing success ratio with the low message overhead. In addition, the EBLLD algorithm is scalable and applicable to large-scale Ad Hoc network.
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paper_title: Link stability models for QoS ad hoc routing algorithms

paper_content:

In an ad hoc network, the topology varies as a result of the mobility of its mobile hosts. Consequently, the task of performing ad hoc network routing is more complex and less efficient. Many ad hoc network routing protocols have been proposed. However, more work is required in developing scalable ad hoc routing protocols that support quality-of-service (QoS). Recently, our study shows that link stability (in term of link survival time) has great impact on QoS performance of routing in ad hoc networks. We developed a number of models which effectively estimate link stability for different network movement patterns. By implementing link stability, which is a standalone network parameter, the QoS performance of varieties of ad hoc routing algorithms could be improved when networks are subjected to topological changes, to variations in traffic loading patterns (including a multitude of traffic classes). In this paper, we show that QoS performance of AODV is improved by implementing link stability parameter.
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paper_title: Routing protocol with QoS guarantees for ad-hoc network

paper_content:

A novel routing protocol for ad-hoc networks, delay sensitive adaptive routing protocol (DSARP), is presented, which not only provides a reliable route for delay-sensitive traffic, but also can select the route based on the constrained condition: ‘the shortest route and the lowest average delay’. Therefore, the DSARP is assured to provide QoS guarantee and improve the performance of the network. Simulation results show that DSARP outperforms the dynamic source routing protocol used in ad-hoc wireless networks.
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paper_title: An application-aware qos routing scheme with improved stability for multimedia applications in mobile ad hoc networks

paper_content:

Both delay and bandwidth are the crucial node state information considered in QoS routing schemes for multimedia applications in mobile Ad Hoc networks. In this paper, we propose an application-aware QoS routing scheme for multimedia applications in mobile Ad Hoc networks. In our scheme, the real time control protocol (RTCP) is used to estimate the node state instead of the additional probing messages, and an optimally stable route can be established according to QoS requirements of the multimedia application based on the node state information. It has been shown that the routing performance is improved significantly compared to the existing schemes using the additional probing messages.
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paper_title: A QoS routing method for ad-hoc networks based on genetic algorithm

paper_content:

A lot of work has been done on routing in MANETs. However, the proposed routing resolutions deal only with the best effort data traffic. Connections with quality of service (QoS) requirements are not supported. QoS routing has been receiving increasingly intensive attention in the wireline network domain. However, for MANETs only few QoS algorithms are proposed to be developed and QoS routing algorithms should be adaptive, flexible, and intelligent. We propose a genetic algorithm (GA) based routing method for Mobile Ad-Hoc Networks (GAMAN). Robustness rather that optimality is the primary concern of GAMAN. The GAMAN uses two QoS parameters for routing. The performance evaluation via simulations shows that GAMAN is a promising QoS routing algorithm for MANETs.
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paper_title: Ad-hoc on-demand distance vector routing

paper_content:

An ad-hoc network is the cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. We present Ad-hoc On Demand Distance Vector Routing (AODV), a novel algorithm for the operation of such ad-hoc networks. Each mobile host operates as a specialized router, and routes are obtained as needed (i.e., on-demand) with little or no reliance on periodic advertisements. Our new routing algorithm is quite suitable for a dynamic self starting network, as required by users wishing to utilize ad-hoc networks. AODV provides loop-free routes even while repairing broken links. Because the protocol does not require global periodic routing advertisements, the demand on the overall bandwidth available to the mobile nodes is substantially less than in those protocols that do necessitate such advertisements. Nevertheless we can still maintain most of the advantages of basic distance vector routing mechanisms. We show that our algorithm scales to large populations of mobile nodes wishing to form ad-hoc networks. We also include an evaluation methodology and simulation results to verify the operation of our algorithm.
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paper_title: Energy Efficient Routing Protocols for Mobile Ad Hoc Networks

paper_content:

Summary Although establishing correct and efficient routes is an important design issue in mobile ad hoc networks (MANETs), a more challenging goal is to provide energy efficient routes because mobile nodes’ operation time is the most critical limiting factor. This article surveys and classifies the energy-aware routing protocols proposed for MANETs. They minimize either the active communication energy required to transmit or receive packets or the inactive energy consumed when a mobile node stays idle but listens to the wireless medium for any possible communication requests from other nodes. Transmission power control approach and load distribution approach belong to the former category, and sleep/power-down mode approach belongs to the latter category. While it is not clear whether any particular algorithm or a class of algorithms is the best for all scenarios, each protocol has definite advantages/disadvantages and is well suited for certain situations. The purpose of this paper is to facilitate the research efforts in combining the existing solutions to offer a more energy efficient routing mechanism. Copyright # 2003 John Wiley & Sons, Ltd.
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paper_title: QoS routing performance in multihop, multimedia, wireless networks

paper_content:

We propose an approach to QoS (quality of service) routing in a multimedia, multihop, wireless network. The wireless net can be either stand alone, or connected to the wired net. The main focus of the paper is the QoS routing procedure which can inform the source of the bandwidth and quality of service available to any destination in the wireless network. This knowledge enables the establishment of QoS connections within the wireless network and the efficient support of real time, multimedia traffic. In addition, it enables more effective call acceptance control. In the case of an ATM interconnection, QoS information permits one to extend the ATM virtual circuit service to the wireless network, with possible renegotiation of QoS parameters at the gateway. Simulation experiments show the efficiency of QoS routing in selected multihop, mobile radio network scenarios.
---
paper_title: Routing Support for Providing Guaranteed End-To-End Quality-Of-Service

paper_content:

The up-coming Gbps high-speed networks are expected to support a wide range of real-time, communication-intensive applications. The quality-of-service (QoS) requirements for the timely delivery of multimedia information raise new challenges for the development of integrated-service broadband networks. One of the key issues is QoS routing, which allows selecting network routes with sufficient resources for requested QoS parameters. The goal of QoS routing solutions is two-fold: satisfying the QoS requirements for every admitted connection and achieving global efficiency in resource utilization. ::: Many unicast/multicast QoS routing algorithms were published recently. However, there still exist a lot of unsolved problems in this area. A few examples are listed as follows. (1) There lacks a simple solution with predictable performance and adjustable overhead for the NP-complete multi-constraint routing problem. (2) All existing algorithms are tailored towards specific problems, and there lacks a simple, general routing framework which can be easily extended to handle new problems. (3) Most routing algorithms assume the availability of precise state information about the network, which however is impractical in the real world. ::: We address the above problems, and the goal of this dissertation is to provide simple, general and extensible solutions for QoS routing. We study different routing strategies, compare them and outline the challenges. We propose various algorithms based on different network state models, evaluate these algorithms by analysis and simulation, discuss their strengths and weaknesses of different routing strategies, and compare them with the existing algorithms. The major achievement of this dissertation is outlined in the following. (1) A heuristic approach is proposed to solve the multi-constraint routing problem. It allows the dynamic tradeoff between performance and overhead. (2) A distributed routing framework is proposed to integrate a family of routing algorithms which support applications with QoS requirements on bandwidth, delay, delay jitter, cost, path length, and their combination. (3) Source and distributed routing algorithms axe proposed to work with state information which has a high degree of imprecision. (4) Distributed QoS routing algorithms are proposed for mobile ad-hoc networks whose topologies change as nodes move, join, or leave the networks. (5) An integrated framework is proposed to support routing and scheduling of co-existing QoS and best-effort flows.
---
paper_title: Conditions that impact the complexity of QoS routing

paper_content:

Finding a path in a network based on multiple constraints (the MCP problem) is often considered an integral part of quality of service (QoS) routing. QoS routing with constraints on multiple additive measures has been proven to be NP-complete. This proof has dramatically influenced the research community, resulting into the common belief that exact QoS routing is intractable in practice. However, to our knowledge, no one has ever examined which "worst cases" lead to intractability. In fact, the MCP problem is not strong NP-complete, suggesting that in practice an exact QoS routing algorithm may work in polynomial time. The goal of this paper is to argue that in practice QoS routing may be tractable. We will provide properties, an approximate analysis, and simulation results to indicate that NP-completeness hinges on four conditions, namely: 1) the topology; 2) the granularity of link weights; 3) the correlation between link weights; and 4) the constraints. We expect that, in practice, these conditions are manageable and therefore believe that exact QoS routing is tractable in practice.
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paper_title: QoS-aware routing based on bandwidth estimation for mobile ad hoc networks

paper_content:

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support.
---
paper_title: A position-based QoS routing scheme for UWB mobile ad hoc networks

paper_content:

Ultra-wideband (UWB) wireless communication is a promising spread-spectrum technology that supports very high data rates and provides precise position information of mobile users. In this paper, we present a position-based quality-of-service (QoS) routing scheme for UWB mobile ad hoc networks. The scheme applies call admission control and temporary bandwidth reservation for discovered routes, taking into consideration the medium access control interactions. Via cross-layer design, it exploits UWB advantages at the network layer by using the position information in routing and bandwidth reservation and by supporting the multirate capability. Simulation results demonstrate that the proposed routing scheme is effective in end-to-end QoS support.
---
paper_title: Contention-aware admission control for ad hoc networks

paper_content:

An admission control algorithm must coordinate between flows to provide guarantees about how the medium is shared. In wired networks, nodes can monitor the medium to see how much bandwidth is being used. However, in ad hoc networks, communication from one node may consume the bandwidth of neighboring nodes. Therefore, the bandwidth consumption of flows and the available resources to a node are not local concepts, but related to the neighboring nodes in carrier-sensing range. Current solutions do not address how to perform admission control in such an environment so that the admitted flows in the network do not exceed network capacity. In this paper, we present a scalable and efficient admission control framework - contention-aware admission control protocol (CACP) - to support QoS in ad hoc networks. We present several options for the design of CACP and compare the performance of these options using both mathematical analysis and simulation results. We also demonstrate the effectiveness of CACP compared to existing approaches through extensive simulations.
---
paper_title: A QoS routing method for ad-hoc networks based on genetic algorithm

paper_content:

A lot of work has been done on routing in MANETs. However, the proposed routing resolutions deal only with the best effort data traffic. Connections with quality of service (QoS) requirements are not supported. QoS routing has been receiving increasingly intensive attention in the wireline network domain. However, for MANETs only few QoS algorithms are proposed to be developed and QoS routing algorithms should be adaptive, flexible, and intelligent. We propose a genetic algorithm (GA) based routing method for Mobile Ad-Hoc Networks (GAMAN). Robustness rather that optimality is the primary concern of GAMAN. The GAMAN uses two QoS parameters for routing. The performance evaluation via simulations shows that GAMAN is a promising QoS routing algorithm for MANETs.
---
paper_title: QoS-aware routing based on bandwidth estimation for mobile ad hoc networks

paper_content:

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Therefore, the network may easily become overloaded with too much traffic and the application has no way to improve its performance under a given network traffic condition. While this may be acceptable for data transfer, many real-time applications require quality-of-service (QoS) support from the network. We believe that such QoS support can be achieved by either finding a route to satisfy the application requirements or offering network feedback to the application when the requirements cannot be met. We propose a QoS-aware routing protocol that incorporates an admission control scheme and a feedback scheme to meet the QoS requirements of real-time applications. The novel part of this QoS-aware routing protocol is the use of the approximate bandwidth estimation to react to network traffic. Our approach implements these schemes by using two bandwidth estimation methods to find the residual bandwidth available at each node to support new streams. We simulate our QoS-aware routing protocol for nodes running the IEEE 802.11 medium access control. Results of our experiments show that the packet delivery ratio increases greatly, and packet delay and energy dissipation decrease significantly, while the overall end-to-end throughput is not impacted, compared with routing protocols that do not provide QoS support.
---
paper_title: Contention-aware admission control for ad hoc networks

paper_content:

An admission control algorithm must coordinate between flows to provide guarantees about how the medium is shared. In wired networks, nodes can monitor the medium to see how much bandwidth is being used. However, in ad hoc networks, communication from one node may consume the bandwidth of neighboring nodes. Therefore, the bandwidth consumption of flows and the available resources to a node are not local concepts, but related to the neighboring nodes in carrier-sensing range. Current solutions do not address how to perform admission control in such an environment so that the admitted flows in the network do not exceed network capacity. In this paper, we present a scalable and efficient admission control framework - contention-aware admission control protocol (CACP) - to support QoS in ad hoc networks. We present several options for the design of CACP and compare the performance of these options using both mathematical analysis and simulation results. We also demonstrate the effectiveness of CACP compared to existing approaches through extensive simulations.
---
paper_title: A paradigm for quality-of-service in wireless ad hoc networks using synchronous signaling and node states

paper_content:

Most limitations in mechanisms geared at achieving quality-of-service (QoS) in wireless ad hoc networking can be traced to solutions based on mapping wireless networks to a wireline paradigm of nodes and links. We contend that this paradigm is not appropriate since links are not physical entities and do not accurately represent the radio frequency (RF) media. Using the link abstraction makes arbitration of the use of the RF media cumbersome leaving only overprovisioning techniques to deliver QoS. In this paper, we argue that an appropriate paradigm should match the physics of the network. The critical resource is electromagnetic spectrum in a space; in turn, this results in a complex paradigm since the part of the spectrum-space that each node wants to use is unique to that node and its destination and will overlap with parts that other nodes may want to use creating interdependences among nodes. This paper describes protocol approaches for access and routing that seek solutions within this wireless paradigm. Access is arbitrated using synchronous signaling and topology is resolved through the dissemination of node states. This approach provides an intuitive framework that provides mechanisms that can be exploited to arbitrate RF media use and implement traffic engineering techniques to deliver QoS. Our proposed approach provides a novel way of tracking the state of the network that can serve as a unified state dissemination mechanism to simultaneously support routing, multicasting, and most QoS heuristics.
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Title: A survey of QoS routing solutions for mobile ad hoc networks

Section 1: ABSTRACT
Description 1: This section provides an overview of the paper, summarizing the challenges of QoS in MANETs, the focus on QoS routing protocols, and the survey's objectives, which include discussing major contributions, classifying protocols, and identifying future research areas.

Section 2: RELATED WORK
Description 2: This section reviews previous surveys of QoS routing solutions in MANETs and highlights the main conclusions and future work identified by those surveys.

Section 3: QOS ROUTING PROTOCOL DESIGN CONSIDERATIONS
Description 3: This section discusses the key metrics used to specify QoS requirements, such as throughput, delay, and packet loss ratio, along with the metrics employed for route selection and protocol evaluation.

Section 4: FACTORS AFFECTING QOS PROTOCOL PERFORMANCE
Description 4: This section outlines factors impacting QoS protocol performance including node mobility, network size, traffic characteristics, transmission power, and channel characteristics.

Section 5: NETWORK RESOURCES REQUIRED IN ORDER TO PROVIDE QOS
Description 5: This section enumerates the network resources necessary for providing QoS, such as node computing time, battery charge, buffer space, and channel capacity.

Section 6: DESIGN TRADE-OFFS
Description 6: This section presents common trade-offs in QoS routing protocol design, such as proactive vs. reactive routing, capacity vs. delay, packet loss ratio, and energy consumption.

Section 7: PROTOCOL CLASSIFICATION
Description 7: This section groups QoS routing protocols based on various criteria such as topology management, route discovery approach, interaction with the MAC layer, and metrics employed for path evaluation and selection.

Section 8: PROTOCOLS RELYING ON CONTENTION-FREE MAC
Description 8: This section provides examples of QoS routing protocols that rely on contention-free MAC protocols like TDMA, detailing their methodologies and specific cases.

Section 9: PROTOCOLS BASED ON CONTENDED MAC
Description 9: This section examines protocols designed to work with contended MAC protocols such as 802.11, discussing their techniques for achievable throughput estimation and session admission control.

Section 10: PROTOCOLS INDEPENDENT OF THE TYPE OF MAC
Description 10: This section reviews QoS routing protocols that do not depend on a specific MAC protocol, focusing on their capabilities to improve general QoS metrics without guaranteeing strict service levels.

Section 11: TRENDS AND PROGRESS IN THE FIELD
Description 11: This section highlights the recent trends and advancements in the field of QoS routing for MANETs, observing shifts from contention-free to contended MAC, and the move towards multiconstraint routing.

Section 12: FUTURE WORK
Description 12: This section identifies topics for future research, including accurate throughput estimation, session completion rates, the impact of realistic channel models, optimization for multiconstraint routing, and the development of practical protocol frameworks.

Section 13: SUMMARY
Description 13: This section provides a concise summary of the paper, reiterating the challenges, contributions, classifications, protocol interactions, trends, and identified future research areas in the field of QoS routing for MANETs.