A survey on energy efficiency for wireless mesh network
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paper_title: Wireless mesh networks: a survey

paper_content:

Wireless mesh networks (WMNs) consist of mesh routers and mesh clients, where mesh routers have minimal mobility and form the backbone of WMNs. They provide network access for both mesh and conventional clients. The integration of WMNs with other networks such as the Internet, cellular, IEEE 802.11, IEEE 802.15, IEEE 802.16, sensor networks, etc., can be accomplished through the gateway and bridging functions in the mesh routers. Mesh clients can be either stationary or mobile, and can form a client mesh network among themselves and with mesh routers. WMNs are anticipated to resolve the limitations and to significantly improve the performance of ad hoc networks, wireless local area networks (WLANs), wireless personal area networks (WPANs), and wireless metropolitan area networks (WMANs). They are undergoing rapid progress and inspiring numerous deployments. WMNs will deliver wireless services for a large variety of applications in personal, local, campus, and metropolitan areas. Despite recent advances in wireless mesh networking, many research challenges remain in all protocol layers. This paper presents a detailed study on recent advances and open research issues in WMNs. System architectures and applications of WMNs are described, followed by discussing the critical factors influencing protocol design. Theoretical network capacity and the state-of-the-art protocols for WMNs are explored with an objective to point out a number of open research issues. Finally, testbeds, industrial practice, and current standard activities related to WMNs are highlighted.
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paper_title: Span: an energy-efficient coordination algorithm for topology maintenance in ad hoc wireless networks

paper_content:

This paper presents Span, a power saving technique for multi-hop ad hoc wireless networks that reduces energy consumption without significantly diminishing the capacity or connectivity of the network. Span builds on the observation that when a region of a sharedchannel wireless network has a sufficient density of nodes, only a small number of them need be on at any time to forward traffic for active connections. Span is a distributed, randomized algorithm where nodes make local decisions on whether to sleep, or to join a forwarding backbone as a coordinator. Each node bases its decision on an estimate of how many of its neighbors will benefit from it being awake, and the amount of energy available to it. We give a randomized algorithm where coordinators rotate with time, demonstrating how localized node decisions lead to a connected, capacity-preserving global topology. Improvement in system lifetime due to Span increases as the ratio of idle-to-sleep energy consumption increases. Our simulations show that with a practical energy model, system lifetime of an 802.11 network in power saving mode with Span is a factor of two better than without. Additionally, Span also improves communication latency and capacity.
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paper_title: A channel access scheme for large dense packet radio networks

paper_content:

Prior work in the field of packet radio networks has often assumed a simple success-if-exclusive model of successful reception. This simple model is insufficient to model interference in large dense packet radio networks accurately. In this paper we present a model that more closely approximates communication theory and the underlying physics of radio communication. Using this model we present a decentralized channel access scheme for scalable packet radio networks that is free of packet loss due to collisions and that at each hop requires no per-packet transmissions other than the single transmission used to convey the packet to the next-hop station. We also show that with a modest fraction of the radio spectrum, pessimistic assumptions about propagation resulting in maximum-possible self-interference, and an optimistic view of future signal processing capabilities that a self-organizing packet radio network may scale to millions of stations within a metro area with raw per-station rates in the hundreds of megabits per second.
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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: A channel access scheme for large dense packet radio networks

paper_content:

Prior work in the field of packet radio networks has often assumed a simple success-if-exclusive model of successful reception. This simple model is insufficient to model interference in large dense packet radio networks accurately. In this paper we present a model that more closely approximates communication theory and the underlying physics of radio communication. Using this model we present a decentralized channel access scheme for scalable packet radio networks that is free of packet loss due to collisions and that at each hop requires no per-packet transmissions other than the single transmission used to convey the packet to the next-hop station. We also show that with a modest fraction of the radio spectrum, pessimistic assumptions about propagation resulting in maximum-possible self-interference, and an optimistic view of future signal processing capabilities that a self-organizing packet radio network may scale to millions of stations within a metro area with raw per-station rates in the hundreds of megabits per second.
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paper_title: Asymptotically optimal power-aware routing for multihop wireless networks with renewable energy sources

paper_content:

In this paper, we model and characterize the performance of multihop radio networks in the presence of energy constraints and design routing algorithms to optimally utilize the available energy. The energy model allows vastly different energy sources in heterogeneous environments. The proposed algorithm is shown to achieve a competitive ratio (i.e., the ratio of the performance of any off-line algorithm that has knowledge of all past and future packet arrivals to the performance of our online algorithm) that is asymptotically optimal with respect to the number of nodes in the network. The algorithm assumes no statistical information on packet arrivals and can easily be incorporated into existing routing frameworks (e.g., proactive or on-demand methodologies) in a distributed fashion. Simulation results confirm that the algorithm performs very well in terms of maximizing the throughput of an energy-constrained network. Further, a new threshold-based scheme is proposed to reduce the routing overhead while incurring only minimum performance degradation.
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paper_title: Energy-efficient communication protocol for wireless microsensor networks

paper_content:

Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. In this paper, we look at communication protocols, which can have significant impact on the overall energy dissipation of these networks. Based on our findings that the conventional protocols of direct transmission, minimum-transmission-energy, multi-hop routing, and static clustering may not be optimal for sensor networks, we propose LEACH (Low-Energy Adaptive Clustering Hierarchy), a clustering-based protocol that utilizes randomized rotation of local cluster based station (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show the LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional outing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated.
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paper_title: The pulse protocol: energy efficient infrastructure access

paper_content:

We present the pulse protocol which is designed for multi-hop wireless infrastructure access. While similar to the more traditional access point model, it is extended to operate across multiple hops. This is particularly useful for conference, airport, or large corporate deployments. In these types of environments where users are highly mobile, energy efficiency becomes of great importance. The pulse protocol utilizes a periodic flood initiated at the network gateways which provides both routing and synchronization to the network. This synchronization is used to allow idle nodes to power off their radios for a large percentage of the time when they are not needed for packet forwarding. This results in substantial energy savings. Through simulation we validate the performance of the routing protocol with respect to both packet delivery and energy savings.
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paper_title: Towards an Energy-Star WLAN Infrastructure

paper_content:

Mobile users' demand for omnipresent, reliable, and high throughput services from a wireless LAN infrastructure has led a significant number of enterprises and public bodies to deploy large-scale high-density IEEE 802.11-based WLANs. These WLANs feature several hundreds to thousands of APs that are managed centrally and are typically dimensioned for peak user demands. Unfortunately, peak demands are occasional and WLANs often under-utilized. Using measurements from two different WLANs we show that the under-utilization of WLANs leads to a significant energy wastage, primarily due to their always-on nature. We discuss designs that can render such WLANs energy efficient and describe energy star infrastructures that can maximize energy savings in different scenarios. We also propose a simple algorithm, Green-clustering for energy star WLAN infrastructures that can lead to up to 90% energy savings. We argue that current and future large-scale WLANs must integrate energy efficiency as a design constraint. We also discuss avenues of further research on energy-star WLAN infrastructures.
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paper_title: Power-efficient access-point selection for indoor location estimation

paper_content:

An important goal of indoor location estimation systems is to increase the estimation accuracy while reducing the power consumption. In this paper, we present a novel algorithm known as CaDet for power-efficient location estimation by intelligently selecting the number of access points (APs) used for location estimation. We show that by employing machine learning techniques, CaDet is able to use a small subset of the APs in the environment to detect a client's location with high accuracy. CaDet uses a combination of information theory, clustering analysis, and a decision tree algorithm. By collecting data and testing our algorithms in a realistic WLAN environment in the computer science department area of the Hong Kong University of Science and Technology, we show that CaDet (clustering and decision tree-based method) can be much higher in accuracy as compared to other methods. We also show through experiments that, by intelligently selecting APs, we are able to save the power on the client device while achieving the same level of accuracy.
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paper_title: Energy Profile Aware Routing

paper_content:

Energy efficient communication devices are essential to minimize the operational cost of future networks and to reduce the negative effects of global warming. In this paper we propose a novel energy reduction approach on network level that takes load-dependent energy consumption information of communication equipment into account. Case study calculation results show that energy savings of more than 35% and with it operational cost can be saved by applying energy profile aware routing.
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paper_title: Throughput and energy-aware routing for 802.11 based mesh networks

paper_content:

In this paper we propose a novel routing algorithm for 802.11 based wireless mesh networks called Energy and Throughput-aware Routing (ETR). The design objectives of ETR are (i) to provide flows with throughput guarantees, and (ii) to minimize the overall energy consumption in the mesh network. To achieve these objectives, we first analyze the throughput performance of the mesh network. Based on this analysis, we target obtaining the set of feasible allocations in the wireless network, i.e., the capacity region, which results in a set of complex non-linear equations that are not adequate for optimization algorithms. To overcome this computational complexity we derive a set of linear constraints (referred to as linearized capacity regions) which provides a much simpler formulation at a slightly reduced accuracy. By feeding these linear constraints into an integer programming formulation, we then propose a routing algorithm that admits as many flows as possible while satisfying their throughput guarantees. This algorithm is further extended to account for energy considerations by devising a routing algorithm that uses as few nodes as possible, which allows switching off the unused nodes and thus save energy. The proposed approach is thoroughly evaluated and shown to outperform previous approaches very substantially both in terms of throughput and energy consumption.
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paper_title: EFFICIENT ROUTING PROTOCOL TO SUPPORT QOS IN WIRELESS MESH NETWORK

paper_content:

The wireless mesh network is a new emerging technology that will change the world of industrial networks connectivity to more efficient and profitable. Mesh networks consist of static wireless nodes and mobile customer; have emerged as a key technology fornew generation networks. The Quality of Service (QOS) is designed to promote and support multimedia applications (audio and video), real time. However guarantee of QoS on wireless networks is a difficult problem by comparison at its deployment in a wired IP network. In this paper, we present an efficient routing protocol named as “QoS- Cluster Based Routing Protocol” (Q-CBRP) to support QoS in Wireless Mesh Network.
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paper_title: The pulse protocol: energy efficient infrastructure access

paper_content:

We present the pulse protocol which is designed for multi-hop wireless infrastructure access. While similar to the more traditional access point model, it is extended to operate across multiple hops. This is particularly useful for conference, airport, or large corporate deployments. In these types of environments where users are highly mobile, energy efficiency becomes of great importance. The pulse protocol utilizes a periodic flood initiated at the network gateways which provides both routing and synchronization to the network. This synchronization is used to allow idle nodes to power off their radios for a large percentage of the time when they are not needed for packet forwarding. This results in substantial energy savings. Through simulation we validate the performance of the routing protocol with respect to both packet delivery and energy savings.
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paper_title: Energy Profile Aware Routing

paper_content:

Energy efficient communication devices are essential to minimize the operational cost of future networks and to reduce the negative effects of global warming. In this paper we propose a novel energy reduction approach on network level that takes load-dependent energy consumption information of communication equipment into account. Case study calculation results show that energy savings of more than 35% and with it operational cost can be saved by applying energy profile aware routing.
---
paper_title: Power-efficient access-point selection for indoor location estimation

paper_content:

An important goal of indoor location estimation systems is to increase the estimation accuracy while reducing the power consumption. In this paper, we present a novel algorithm known as CaDet for power-efficient location estimation by intelligently selecting the number of access points (APs) used for location estimation. We show that by employing machine learning techniques, CaDet is able to use a small subset of the APs in the environment to detect a client's location with high accuracy. CaDet uses a combination of information theory, clustering analysis, and a decision tree algorithm. By collecting data and testing our algorithms in a realistic WLAN environment in the computer science department area of the Hong Kong University of Science and Technology, we show that CaDet (clustering and decision tree-based method) can be much higher in accuracy as compared to other methods. We also show through experiments that, by intelligently selecting APs, we are able to save the power on the client device while achieving the same level of accuracy.
---
paper_title: Towards an Energy-Star WLAN Infrastructure

paper_content:

Mobile users' demand for omnipresent, reliable, and high throughput services from a wireless LAN infrastructure has led a significant number of enterprises and public bodies to deploy large-scale high-density IEEE 802.11-based WLANs. These WLANs feature several hundreds to thousands of APs that are managed centrally and are typically dimensioned for peak user demands. Unfortunately, peak demands are occasional and WLANs often under-utilized. Using measurements from two different WLANs we show that the under-utilization of WLANs leads to a significant energy wastage, primarily due to their always-on nature. We discuss designs that can render such WLANs energy efficient and describe energy star infrastructures that can maximize energy savings in different scenarios. We also propose a simple algorithm, Green-clustering for energy star WLAN infrastructures that can lead to up to 90% energy savings. We argue that current and future large-scale WLANs must integrate energy efficiency as a design constraint. We also discuss avenues of further research on energy-star WLAN infrastructures.
---
paper_title: Asymptotically optimal power-aware routing for multihop wireless networks with renewable energy sources

paper_content:

In this paper, we model and characterize the performance of multihop radio networks in the presence of energy constraints and design routing algorithms to optimally utilize the available energy. The energy model allows vastly different energy sources in heterogeneous environments. The proposed algorithm is shown to achieve a competitive ratio (i.e., the ratio of the performance of any off-line algorithm that has knowledge of all past and future packet arrivals to the performance of our online algorithm) that is asymptotically optimal with respect to the number of nodes in the network. The algorithm assumes no statistical information on packet arrivals and can easily be incorporated into existing routing frameworks (e.g., proactive or on-demand methodologies) in a distributed fashion. Simulation results confirm that the algorithm performs very well in terms of maximizing the throughput of an energy-constrained network. Further, a new threshold-based scheme is proposed to reduce the routing overhead while incurring only minimum performance degradation.
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paper_title: A channel access scheme for large dense packet radio networks

paper_content:

Prior work in the field of packet radio networks has often assumed a simple success-if-exclusive model of successful reception. This simple model is insufficient to model interference in large dense packet radio networks accurately. In this paper we present a model that more closely approximates communication theory and the underlying physics of radio communication. Using this model we present a decentralized channel access scheme for scalable packet radio networks that is free of packet loss due to collisions and that at each hop requires no per-packet transmissions other than the single transmission used to convey the packet to the next-hop station. We also show that with a modest fraction of the radio spectrum, pessimistic assumptions about propagation resulting in maximum-possible self-interference, and an optimistic view of future signal processing capabilities that a self-organizing packet radio network may scale to millions of stations within a metro area with raw per-station rates in the hundreds of megabits per second.
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paper_title: Power saving access points for IEEE 802-11 wireless network infrastructure

paper_content:

In the past decade, there has been a huge proliferation of wireless local area networks (WLANs) based on the IEEE 802.11 WLAN standard. As 802.11 connectivity becomes more ubiquitous, multihop communications will be increasingly used for access point range extension and coverage enhancement. In this paper, we present a design for an IEEE 802. 11 -based power saving access point (PSAP), intended for use in multihop battery and solar/battery powered applications. These types of APs have many practical applications and can be deployed very quickly and inexpensively to provide coverage enhancement in situations such as campuses, building complexes, and fast deployment scenarios. Unlike conventional wired access points, in this type of system, power saving on the AP itself is an important objective. A key design constraint is that the proposed PSAP be backward compatible to a wide range of IEEE 802.11 functionality and existing wired access points. In this paper, we introduce the protocols required to achieve this compatibility, show the constraints imposed by this restriction, and present performance results for the proposed system.
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paper_title: Access point power saving in solar/battery powered IEEE 802.11 ESS mesh networks

paper_content:

IEEE 802.11 access point (AP) power saving is an important feature for solar/battery powered ESS mesh networks. In this paper we propose a media access control (MAC) protocol for power-aware multihop infrastructure, based on extensions to IEEE 802.11(e). A power saving mesh AP includes a network allocation map (NAM) in its beacon broadcasts which specifies its temporal operation, and thus coordinates traffic delivery and power saving at both end stations and at the AP. A simple algorithm is proposed for dynamically updating channel activities so that best-effort traffic load changes can be quickly accommodated. Simulation and analytic results are presented for the proposed system which show that the proposed protocol and algorithm can achieve good AP power consumption without any significant end station performance degradation
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paper_title: SOFA: A Sleep-Optimal Fair-Attention Scheduler for the Power-Saving Mode of WLANs

paper_content:

Mobile devices adopt the IEEE 802.11 PSM (Power-Saving Mode) scheme and its enhancements to reduce their energy consumption when using Wi-Fi interfaces. However, the capability of PSM to save energy is limited when the WLANs are highly congested by other Wi-Fi clients. In this paper, instead of further pursuing the trade-off between power saving and the incurred delay on the client side, we take a different approach and explore the energy saving potential by considering the scheduling policy on the Access Point (AP) side. We find that the traditional packet-level first-come-first-serve policy is not sleep optimal since it keeps the PSM clients awake unnecessarily. We propose SOFA, an AP-centric scheme, which helps PSM clients save energy by minimizing the time they are forced to stay awake while down link traffic is being transmitted to other clients. SOFA delivers down link packets to the PSM clients in an optimal sequence, such that several objective are simultaneously achieved: (i) system-sleep optimality, (ii) energy-fairness, (iii) attention fairness, and (iv) no unnecessary deferral of packets beyond a beacon period. First, it determines an attention quota for each client at the beginning of each beacon period, without requiring any knowledge of available wireless capacity. Then it takes the attention "quota'' and attention request as inputs to decide the down link packet scheduling. We prove the stability and optimality of SOFA. Simulation results shows SOFA dramatically decreases the energy consumption of PSM clients in a crowded WLAN, especially for those clients with small attention requests.
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paper_title: Physical rate and contention window based admission control (PRCW) for 802.11 WLANs

paper_content:

Quality of service (QoS) is a key problem in wireless environments where bandwidth is scarce and channel conditions are time varying and sometimes implies highly packet losses. IEEE 802.11b/g/a wireless LAN (WLAN) are the most widely used WLAN standards today, and the IEEE 802.11e QoS enhancement standard exists and introduces QoS support for multimedia applications. This paper presents a class based admission control algorithm for 802.11e based wireless local area networks. The strengths of our admission control is dynamicity and flexibility of the algorithm, which adapts to the situation of the BSS, like global load, number of best effort AC, and position of QSTA by report of QAP, thing that have never been taken together, but each solutions have used a point of sight separately. Thus it achieves higher throughput than other admission control for 802.11 e. The idea which consists of changing parameters [AIFSN, CWmin and CWmax] of best effort flows, for decreasing collisions, is used, so we think that it is an efficient way to protect QoS flows from best effort flows, and to allow reducing then number of collisions. So we increase AIFSN [best effort flow], CWmin and CWmax only at 70% of load of network, to prevent starvations of best effort flows, and so we increase rate utilization of channel. We also use the current rate transmission of QSTAs, according to their positions, instead of the minimum rate transmission used by standard 802.11e, for calculate the load of network and derived the TXOPi necessary for all the stations, with i=1 to number of active stations. The 802.11e standard starves the low priority traffic in case of high load, and leads to higher collision rates, and did not make a good estimate of weight of queues, so there is an unbalance enters the flows with high priorities. A discussion is presented in detail using simulation-based evaluations, with an aim of comparing results of our admission control algorithm, with the 802.11e standard and the FHCF algorithm. Results reveal an improvement of the network load and a decrease of the number of collisions.
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paper_title: Energy-efficient communication protocol for wireless microsensor networks

paper_content:

Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. In this paper, we look at communication protocols, which can have significant impact on the overall energy dissipation of these networks. Based on our findings that the conventional protocols of direct transmission, minimum-transmission-energy, multi-hop routing, and static clustering may not be optimal for sensor networks, we propose LEACH (Low-Energy Adaptive Clustering Hierarchy), a clustering-based protocol that utilizes randomized rotation of local cluster based station (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show the LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional outing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated.
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paper_title: An energy-efficient MAC protocol for wireless sensor networks

paper_content:

This paper proposes S-MAC, a medium-access control (MAC) protocol designed for wireless sensor networks. Wireless sensor networks use battery-operated computing and sensing devices. A network of these devices will collaborate for a common application such as environmental monitoring. We expect sensor networks to be deployed in an ad hoc fashion, with individual nodes remaining largely inactive for long periods of time, but then becoming suddenly active when something is detected. These characteristics of sensor networks and applications motivate a MAC that is different from traditional wireless MACs such as IEEE 802.11 in almost every way: energy conservation and self-configuration are primary goals, while per-node fairness and latency are less important. S-MAC uses three novel techniques to reduce energy consumption and support self-configuration. To reduce energy consumption in listening to an idle channel, nodes periodically sleep. Neighboring nodes form virtual clusters to auto-synchronize on sleep schedules. Inspired by PAMAS, S-MAC also sets the radio to sleep during transmissions of other nodes. Unlike PAMAS, it only uses in-channel signaling. Finally, S-MAC applies message passing to reduce contention latency for sensor-network applications that require store-and-forward processing as data move through the network. We evaluate our implementation of S-MAC over a sample sensor node, the Mote, developed at University of California, Berkeley. The experiment results show that, on a source node, an 802.11-like MAC consumes 2-6 times more energy than S-MAC for traffic load with messages sent every 1-10 s.
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paper_title: Virtualization of 802.11 interfaces for Wireless Mesh Networks

paper_content:

Equipping wireless devices with multiple radio interfaces enables multi-channel communication that has attracted recent interest due to its significant benefits in terms of exploiting the available radios to increase the throughput and the creation of WLAN-based Mesh Networks. The usage of multiple network interface cards (NICs) demands higher cost, large physical space and more energy consumption. Instead of that, virtualization of NICs is a promising approach that gives a wireless device equipped with a single card the ability to connect to more than one network simultaneously. In this paper, we present two methods for NIC virtualization. With the increasing need for energy-efficient networking and for supporting a continuous delivery of real-time multimedia services (e.g. VoIP, video streaming) despite mobility in order to avoid packet loss and delay resulting from handovers, enhancements and mechanisms are needed. In this paper, we have conducted some simulations to show how virtualization of 802.11 NICs enables energy-efficient Wireless Mesh Networks and soft handover.
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paper_title: A power saving MAC protocol by increasing spatial reuse for IEEE 802.11 ad hoc WLANs

paper_content:

Scarce resources of wireless medium (e.g., bandwidth, battery power, and so on) significantly restrict the progress of wireless local area networks (WLANs). Heavy traffic load and high station density are most likely to incur collisions, and further consume bandwidth and energy. In this paper, a distributed power-saving protocol, power-efficient MAC protocol (PEM), to avoid collisions and to save energy is proposed. PEM takes advantage of power control technique to reduce the interferences among transmission pairs and increase the spatial reuse of WLANs. Based on the concept of maximum independent set (MIS), a novel heuristic scheme with the aid of interference relationship is proposed to provide as many simultaneous transmission pairs as possible. In PEM, all stations know when to wake up and when they can enter doze state. Thus, stations need not waste power to idle listen and can save much power. The network bandwidth can be efficiently utilized as well. To verify the performance of PEM, a lot of simulations are performed. The experimental results show that with the property of spatial reuse, PEM not only reduces power consumption, but also leads to higher network throughput in comparison with the existing work, such as DCF, DCS, and DPSM.
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paper_title: A Multi-hop Energy-efficient Sleeping MAC Protocol based on TDMA Scheduling for Wireless Mesh Sensor Networks

paper_content:

Abstract—Based on Wireless Mesh Network (WMN) theory, according to the characteristics of Wireless Sensor Network (WSN) clustering topology, WSN and WMN are combined to construct Wireless Mesh Sensor Network (WMSN) topology. In order to improve the performance of energy-efficiency, throughput and delay in WMSN, this paper designs a Multi-hop TDMA Energy-efficient Sleeping MAC (MT-MAC) protocol and gives the performance simulation with MATLAB. In MT-MAC, a TDMA frame was divided into a number of time slots for sensor nodes in WMSN to send or receive data packets. As the simulation result shows, compared with SMAC protocol, MT-MAC not only saves 25% energy consumption of the network, but also decreases 45% latency of the whole network.
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paper_title: A Topology Control Algorithm for Effective Power Efficiency and Throughput for Wireless Mesh Networks

paper_content:

Wireless mesh networks (WMNs) have become a better alternative for extending wireless Local Area Networks (WLANs) to provide network coverage up to the furthest of far flung rural areas. This has been implemented by using a meshed backbone network interconnecting the mesh access points (MAPs) that manages each of the WLANs. The routing algorithms use the mesh backbone to establish inter-WLAN routes which are subsequently used by the distantly distributed mesh clients to communicate in a multihop fashion. In this work, a fully scalable power-efficient localized distributed topology control algorithm is proposed to effectively construct such a meshed backbone network of access points. The performance of the algorithm is evaluated via several simulations carried out in the NS-2 simulation environment. The resultant network topology is shown to have (1) reduced average node degree which leads to reduced traffic interference, (2) increased throughput and (3)increased network lifetime.
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paper_title: Span: an energy-efficient coordination algorithm for topology maintenance in ad hoc wireless networks

paper_content:

This paper presents Span, a power saving technique for multi-hop ad hoc wireless networks that reduces energy consumption without significantly diminishing the capacity or connectivity of the network. Span builds on the observation that when a region of a sharedchannel wireless network has a sufficient density of nodes, only a small number of them need be on at any time to forward traffic for active connections. Span is a distributed, randomized algorithm where nodes make local decisions on whether to sleep, or to join a forwarding backbone as a coordinator. Each node bases its decision on an estimate of how many of its neighbors will benefit from it being awake, and the amount of energy available to it. We give a randomized algorithm where coordinators rotate with time, demonstrating how localized node decisions lead to a connected, capacity-preserving global topology. Improvement in system lifetime due to Span increases as the ratio of idle-to-sleep energy consumption increases. Our simulations show that with a practical energy model, system lifetime of an 802.11 network in power saving mode with Span is a factor of two better than without. Additionally, Span also improves communication latency and capacity.
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paper_title: A Topology Control Algorithm for Effective Power Efficiency and Throughput for Wireless Mesh Networks

paper_content:

Wireless mesh networks (WMNs) have become a better alternative for extending wireless Local Area Networks (WLANs) to provide network coverage up to the furthest of far flung rural areas. This has been implemented by using a meshed backbone network interconnecting the mesh access points (MAPs) that manages each of the WLANs. The routing algorithms use the mesh backbone to establish inter-WLAN routes which are subsequently used by the distantly distributed mesh clients to communicate in a multihop fashion. In this work, a fully scalable power-efficient localized distributed topology control algorithm is proposed to effectively construct such a meshed backbone network of access points. The performance of the algorithm is evaluated via several simulations carried out in the NS-2 simulation environment. The resultant network topology is shown to have (1) reduced average node degree which leads to reduced traffic interference, (2) increased throughput and (3)increased network lifetime.
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paper_title: Topology control in wireless ad hoc and sensor networks

paper_content:

Topology Control (TC) aims at tuning the topology of highly dynamic networks to provide better control over network resources and to increase the efficiency of communication. Recently, many TC protocols have been proposed. The protocols are designed for preserving connectivity, minimizing energy consumption, maximizing the overall network coverage or network capacity. Each TC protocol makes different assumptions about the network topology, environment detection resources, and control capacities. This circumstance makes it extremely difficult to comprehend the role and purpose of each protocol. To tackle this situation, a taxonomy for TC protocols is presented throughout this paper. Additionally, some TC protocols are classified based upon this taxonomy.
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paper_title: Virtual WLAN: Going beyond Virtual Access Points

paper_content:

Wireless nodes equipped with multiple radio interfaces open up new fields of application. Ranging from multi-channel usage in a cell in order to increase the bandwidth to the creation of meshed multi-hop topologies. Using multiple wireless cards demands a large physical space, more energy consumption and as a consequence decreasing in the battery lifetime. Virtualization of the wireless network interface, which means to use a single wireless network interface to connect to more than one network simultaneously, seems to be a promising approach, since it allows us to realize the mentioned scenarios only with one radio interface. In this paper, we want to shed light on the state of the art and want to introduce new approaches to push this field beyond the current status.
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paper_title: Reducing Network Energy Consumption via Sleeping and Rate-Adaptation

paper_content:

We present the design and evaluation of two forms of power management schemes that reduce the energy consumption of networks. The first is based on putting network components to sleep during idle times, reducing energy consumed in the absence of packets. The second is based on adapting the rate of network operation to the offered workload, reducing the energy consumed when actively processing packets. ::: ::: For real-world traffic workloads and topologies and using power constants drawn from existing network equipment, we show that even simple schemes for sleeping or rate-adaptation can offer substantial savings. For instance, our practical algorithms stand to halve energy consumption for lightly utilized networks (10-20%). We show that these savings approach the maximum achievable by any algorithms using the same power management primitives. Moreover this energy can be saved without noticeably increasing loss and with a small and controlled increase in latency (<10ms). Finally, we show that both sleeping and rate adaptation are valuable depending (primarily) on the power profile of network equipment and the utilization of the network itself.
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paper_title: Scheduling Optimization in wireless MESH Networks with Power Control and Rate Adaptation

paper_content:

Wireless MESH networks are a new networking paradigm that allow to extend the coverage of traditional wireless access networks with multi-hop connections through fixed wireless mesh routers. Wireless MESH networks partially replace wired backbone networks, and it is reasonable to carefully plan radio resource assignment in order to provide quality guarantees to traffic flows. Differently from ad hoc networks, energy consumption is usually not a problem with wireless MESH routers, routes are quite stable and bandwidth requirements of traffic flows can be considered almost constants. In this paper we study the scheduling optimization problem in wireless MESH networks assuming a time division multiple access (TDMA) scheme, a dynamic power control able to vary emitted power slot-by-slot, and a rate adaptation mechanism that sets transmission rates according to the signal-to-interference-and-noise ratio (SINR). Traffic quality requirements are expressed in terms of minimum bandwidth and modelled with constraints defining the number of information units (packets) that must be transmitted on each link per frame. We propose an alternative problem formulation where decision variables represent compatible sets of links active in the same slot. Approaches to solve both lower and upper bound for the problem are proposed: since compatible set variables are exponentially many, we use column generation to compute a lower bound for the problem. Heuristic approaches to compute feasible integer solutions are proposed and tested
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Title: A Survey on Energy Efficiency for Wireless Mesh Networks
Section 1: INTRODUCTION
Description 1: Introduce the current concerns of global energy consumption, the concept of green networking, and the importance of energy efficiency in Wireless Mesh Networks (WMNs).

Section 2: The CDS (Connected Dominating Set)
Description 2: Describe how the CDS uses neighborhood or topology information to determine nodes that form a connected dominating set for energy-efficient routing.

Section 3: The SPAN
Description 3: Explain the SPAN protocol, which allows nodes to decide whether to sleep or stay awake to conserve energy while maintaining network connectivity.

Section 4: The GAF
Description 4: Discuss the GAF protocol, which uses geographic information to create zones and select coordinators for energy conservation.

Section 5: EMM-DSR protocol
Description 5: Outline the EMM-DSR protocol, which balances energy efficiency and path optimality in data packet forwarding.

Section 6: The Minimum-energy Routing
Description 6: Present the minimum-energy routing approach and how it optimizes energy consumption by selecting routes that minimize total transmit energy.

Section 7: Power-Aware Routing
Description 7: Highlight the power-aware routing algorithms that use composite cost metrics for energy optimization in routing decisions.

Section 8: The Pulse
Description 8: Explain the Pulse protocol, which uses rhythmic pulse floods to maintain routing and conserve energy in multi-hop wireless networks.

Section 9: The green-clustering
Description 9: Detail the green-clustering algorithm that powers on and off WLAN access points based on predefined criteria to save energy.

Section 10: CaDet (clustering and decision-tree-based)
Description 10: Describe the CaDet algorithm that uses clustering and decision trees for reducing power consumption in wireless networks.

Section 11: EAR (Energy Aware Routing)
Description 11: Discuss the concept of energy-aware routing to switch off network components and reduce energy consumption.

Section 12: ETR (Throughput-aware Routing)
Description 12: Explain the ETR method that provides throughput guarantees while optimizing energy consumption in WMNs.

Section 13: Green Framework
Description 13: Detail a new framework for energy management in TDMA-based WMNs aimed at achieving optimal trade-offs between throughput and energy consumption.

Section 14: CBRP (Cluster Based Routing Protocol)
Description 14: Present the Cluster Based Routing Protocol (CBRP) and its efficiency in minimizing flooding traffic to save energy.

Section 15: ENERGY CONSERVATION IN DATA LINK LAYER
Description 15: Discuss various approaches and protocols for energy conservation at the MAC layer of WMNs.

Section 16: ENERGY CONSERVATION IN PHYSICAL LAYER
Description 16: Outline energy-saving techniques and algorithms implemented at the physical layer of WMNs.

Section 17: CONCLUSIONS
Description 17: Summarize the surveyed energy conservation methods and stress the need for further research to combine effective solutions across different network layers.
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