A Survey for Load Balancing in Mobile WiMAX Networks
---
paper_title: WiMAX: Standards and Security

paper_content:

As the demand for broadband services continues to grow worldwide, traditional solutions, such as digital cable and fiber optics, are often difficult and expensive to implement, especially in rural and remote areas. The emerging WiMAX system satisfies the growing need for high data-rate applications such as voiceover IP, video conferencing, interactive gaming, and multimedia streaming. WiMAX deployments not only serve residential and enterprise users but can also be deployed as a backhaul for Wi-Fi hotspots or 3G cellular towers. By providing affordable wireless broadband access, the technology of WiMAX will revolutionize broadband communications in the developed world and bridge the digital divide in developing countries. Part of the WiMAX Handbook, this volume focuses on the standards and security issues of WiMAX. The book examines standardized versus proprietary solutions for wireless broadband access, reviews the core medium access control protocol of WiMAX systems, and presents carriers' perspectives on wireless services. It also discusses the main mobility functions of the IEEE 802.16e standard, describes how to speed up WiMAX handover procedures, presents the 802.16 mesh protocol, and surveys the testing and certification processes used for WiMAX products. In addition, the book reviews the security features of both IEEE 802.16 and WiMAX. With the revolutionary technology of WiMAX, the lives of many will undoubtedly improve, thereby leading to greater economic empowerment.
---
paper_title: Base Station Controlled Load Balancing with Handovers in Mobile WiMAX

paper_content:

In this paper we examine base station controlled handover based load balancing in the mobile WiMAX system and study the framework that mobile WiMAX offers for conducting load balancing and directed handovers. We also propose and evaluate a BS initiated load balancing scheme for mobile WiMAX. The simulations show that the proposed scheme can balance load efficiently within the system but also avoid the so called handover ldquoping-pongrdquo effect especially harmful e.g. for VoIP connections. We also propose an addition to the mobile WiMAX specification to distinguish load balancing based directed handovers and signal quality based rescue handovers conducted by moving terminals. This way the more important rescue handovers can be prioritized in a target Base Station.
---
paper_title: Improved access point selection

paper_content:

This paper presents Virgil, an automatic access point discovery and selection system. Unlike existing systems that select access points based entirely on received signal strength, Virgil scans for all available APs at a location, quickly associates to each, and runs a battery of tests to estimate the quality of each AP's connection to the Internet. Virgil also probes for blocked or redirected ports, to guide AP selection in favor of preserving application services that are currently in use. Results of our evaluation across five neighborhoods in three cities show Virgil finds a usable connection from 22% to 100% more often than selecting based on signal strength alone. By caching AP test results, Virgil both improves performance and success rate. Our overhead is acceptable and is shown to be faster than manually selecting an AP with Windows XP.
---
paper_title: Base Station Controlled Load Balancing with Handovers in Mobile WiMAX

paper_content:

In this paper we examine base station controlled handover based load balancing in the mobile WiMAX system and study the framework that mobile WiMAX offers for conducting load balancing and directed handovers. We also propose and evaluate a BS initiated load balancing scheme for mobile WiMAX. The simulations show that the proposed scheme can balance load efficiently within the system but also avoid the so called handover ldquoping-pongrdquo effect especially harmful e.g. for VoIP connections. We also propose an addition to the mobile WiMAX specification to distinguish load balancing based directed handovers and signal quality based rescue handovers conducted by moving terminals. This way the more important rescue handovers can be prioritized in a target Base Station.
---
paper_title: Analysis of the Increase and Decreas, e Algorithms for Congestion Avoidance in Computer Networks

paper_content:

Congestion avoidance mechanisms allow a network to operate in the optimal region of low delay and high throughput, thereby, preventing the network from becoming congested. This is different from the traditional congestion control mechanisms that allow the network to recover from the congested state of high delay and low throughput. Both con- gestion avoidance and congestion control mechanisms are basi- cally resource management problems. They can be formulated as system control problems in which the system senses its state and feeds this back to its users who adjust their controls. The key component of any congestion avoidance scheme is the algorithm (or control function) used by the users to in- crease or decrease their load (window or rate). We abstractly characterize a wide class of such increase/decreas e algorithms and compare them using several different performance metrics. They key metrics are efficiency, fairness, convergence time, and size of oscillations. It is shown that a simple additive increase and multiplicative decrease algorithm satisfies the sufficient conditions for con- vergence to an efficient and fair state regardless of the starting state of the network. This is the algorithm finally chosen for implementation in the congestion avoidance scheme recom- mended for Digital Networking Architecture and OSI Trans- port Class 4 Networks.
---
paper_title: Load balancing in overlapping wireless LAN cells

paper_content:

We propose a load-balancing scheme for overlapping wireless LAN cells. Agents running in each access point broadcast periodically the local load level via the Ethernet backbone and determines whether the access point is overloaded, balanced or under-loaded by comparing it with the received reports. The load metric is the access point throughput. Overloaded access points force the handoff of some stations to balance the load. Only the under-loaded access points accept the roaming stations in minimizing the number of handoffs. We show via experimental evaluation that our balancing scheme increases the total wireless network throughput and decreases the cell delay.
---
paper_title: Base Station Controlled Load Balancing with Handovers in Mobile WiMAX

paper_content:

In this paper we examine base station controlled handover based load balancing in the mobile WiMAX system and study the framework that mobile WiMAX offers for conducting load balancing and directed handovers. We also propose and evaluate a BS initiated load balancing scheme for mobile WiMAX. The simulations show that the proposed scheme can balance load efficiently within the system but also avoid the so called handover ldquoping-pongrdquo effect especially harmful e.g. for VoIP connections. We also propose an addition to the mobile WiMAX specification to distinguish load balancing based directed handovers and signal quality based rescue handovers conducted by moving terminals. This way the more important rescue handovers can be prioritized in a target Base Station.
---
paper_title: Base Station Controlled Load Balancing with Handovers in Mobile WiMAX

paper_content:

In this paper we examine base station controlled handover based load balancing in the mobile WiMAX system and study the framework that mobile WiMAX offers for conducting load balancing and directed handovers. We also propose and evaluate a BS initiated load balancing scheme for mobile WiMAX. The simulations show that the proposed scheme can balance load efficiently within the system but also avoid the so called handover ldquoping-pongrdquo effect especially harmful e.g. for VoIP connections. We also propose an addition to the mobile WiMAX specification to distinguish load balancing based directed handovers and signal quality based rescue handovers conducted by moving terminals. This way the more important rescue handovers can be prioritized in a target Base Station.
---
paper_title: Adaptive handoff algorithms for dynamic traffic load distribution in 4G mobile networks

paper_content:

In 4G mobile networks which is a kind of packet-based cellular systems, resources are shared among all users and the amount of available resources is determined by traffic load. If traffic load is concentrated in a cell, this cell become to the hotspot cell. The hotspot cell can cause to block or drop calls and consequently degrades the service quality even though available resources are remained in neighboring cells. Therefore, it is essential to distribute traffic load of the hotspot cell in order to effectively use remained resources and maintain the acceptable service quality. We propose adaptive handoff algorithms for dynamic traffic load distribution in the hotspot cell. In the simulation, we find that these algorithms can reduce call drop rate of new and handoff calls thus enhance the service quality
---
paper_title: A dynamic load balancing strategy for channel assignment using selective borrowing in cellular mobile environment

paper_content:

We propose a dynamic load balancing scheme for the channel assignment problem in a cellular mobile environment. As an underlying approach, we start with a fixed assignment scheme where each cell is initially allocated a set of channels, each to be assigned on demand to a user in the cell. A cell is classified as 'hot', if the degree of coldness of a cell (defined as the ratio of the number of available channels to the total number of channels for that cell), is less than or equal to some threshold value. Otherwise the cell is 'cold'. Our load balancing scheme proposes to migrate unused channels from underloaded cells to an overloaded one. This is achieved through borrowing a fixed number of channels from cold cells to a hot one according to a channel borrowing algorithm. A channel assignment strategy is also proposed based on dividing the users in a cell into three broad types – 'new', 'departing', 'others' – and forming different priority classes of channel demands from these three types of users. Assignment of the local and borrowed channels are performed according to the priority classes. Next, a Markov model for an individual cell is developed, where the state is determined by the number of occupied channels in the cell. The probability for a cell being hot and the call blocking probability in a hot cell are derived, and a method to estimate the value of the threshold is also given. Detailed simulation experiments are carried out in order to evaluate our proposed methodology. The performance of our load balancing scheme is compared with the fixed channel assignment, simple borrowing, and two existing strategies with load balancing (e.g., directed retry and CBWL), and a significant improvement of the system behavior is noted in all cases.
---
paper_title: A Novel Inter-FA Handover Scheme for Load Balancing in IEEE 802.16e System

paper_content:

As the demand for high data rate increases, load balancing across cell is highly desirable. A handover (HO) among frequency assignment (FA) may be possible for load balancing theoretically, when a serving FA is crowded to accommodate additional bandwidth request in such system as IEEE 802.16e, where the multiple FAs are possible. However, this handover is impossible in the current specification because an indication to target FA is not defined. It also requires unnecessary long scanning and network re-entry procedure. In this paper, we propose novel inter-FA handover, handover among FAs for load balancing by modifying general handover algorithm. It also satisfies HO user's quality of service (QoS) by reducing HO latency, unnecessary scanning, and network re-entry. We compare with previous HO schemes for load balancing by simulation. We show that this HO scheme can achieve significantly better performance in HO user's QoS and HO delay.
---
paper_title: Load Balance for Multi-Layer Reuse Scenarios on Mobile WiMAX System

paper_content:

This paper intends to propose a novel handover algorithm to balance the load of the layers in a multi-reuse scenario. Each layer works independently from each other and it has its own scheduling process, coverage and mobile stations attached. The algorithm proposed balances the resources among layers by moving mobile stations from one to another layer according their QoS requirements and channel condition. Results show that it can increase the cell coverage and still keeping a satisfactory quality for the VoIP calls. Effective spectral efficiency also increased when comparing with single tri-sectorized reuse 1 scenario. The algorithm is also prepared to avoid ping-pong handovers and to work for any number of layers.
---
paper_title: Base Station Controlled Load Balancing with Handovers in Mobile WiMAX

paper_content:

In this paper we examine base station controlled handover based load balancing in the mobile WiMAX system and study the framework that mobile WiMAX offers for conducting load balancing and directed handovers. We also propose and evaluate a BS initiated load balancing scheme for mobile WiMAX. The simulations show that the proposed scheme can balance load efficiently within the system but also avoid the so called handover ldquoping-pongrdquo effect especially harmful e.g. for VoIP connections. We also propose an addition to the mobile WiMAX specification to distinguish load balancing based directed handovers and signal quality based rescue handovers conducted by moving terminals. This way the more important rescue handovers can be prioritized in a target Base Station.
---
paper_title: An effective traffic management scheme using adaptive handover time in next-generation cellular networks

paper_content:

Next-generation cellular networks are expected to support various multimedia services over IP networks with high spectral efficiency. In these networks, hotspot cells can occur when available wireless resources at some location are not sufficient to sustain the needs of users. The hotspot cell can potentially lead to blocked or dropped calls, which can deteriorate the service quality for users. A group of users enjoying multimedia services could move around in the networks generating heavy flows of traffic. This situation can generate a hotspot cell which has a short lifespan of only a few minutes. If there is a steady increase in the number of these users, the hotspot cell which has a short lifespan will occur more frequently in the overall service area. In this paper, we propose a handover-based traffic management scheme which can effectively deal with hotspot cells in next-generation cellular networks. With our scheme, the current serving cell can recognize the traffic load status of the target cell in advance, before handover execution. Then, according to the load status, it adaptively controls the handover time. The handover-based traffic management scheme can effectively and flexibly handle hotspot cells in the networks. Acceptable service quality can also be supported as users continuously maintain communication links. In the simulation results, we find that our scheme generates a smaller number of hotspot cells and supports higher service quality than the schemes compared.
---
paper_title: Adaptive handoff algorithms for dynamic traffic load distribution in 4G mobile networks

paper_content:

In 4G mobile networks which is a kind of packet-based cellular systems, resources are shared among all users and the amount of available resources is determined by traffic load. If traffic load is concentrated in a cell, this cell become to the hotspot cell. The hotspot cell can cause to block or drop calls and consequently degrades the service quality even though available resources are remained in neighboring cells. Therefore, it is essential to distribute traffic load of the hotspot cell in order to effectively use remained resources and maintain the acceptable service quality. We propose adaptive handoff algorithms for dynamic traffic load distribution in the hotspot cell. In the simulation, we find that these algorithms can reduce call drop rate of new and handoff calls thus enhance the service quality
---
paper_title: A Vertical Handoff Decision Algorithm (VHDA) and a Call Admission Control (CAC) policy in integrated network between WiMax and UMTS

paper_content:

In this paper, we propose to provide ubiquitous access anywhere anytime by covering the remote areas using World Interoperability for microwave access (WiMax), complementing the existing universal mobile telecommunications systems (UMTS). In this proposed system to integrate WiMAX and UMTS, certain areas are covered by both systems. The overlapping areas are modeled as WiMAX cells overlaid with UMTS cells due to the bigger coverage of WiMAX. In order to facilitate the interworking communications between two different systems, we design and develop vertical handoff algorithm and call admission control policy for the interworking system in the overlaid service areas, taking into consideration of the quality of service (QoS), the cost of handoff and other parameters. Typical QoS parameters maybe load balancing, handoff latency, packet loss ratio (PLR) and transmission rates. For the cost of handoff, we consider the mobile velocity, power consumption, available bandwidth, etc. The call admission control (CAC) scheme mainly depends on the wideband power, throughput and the priority of new arrival calls and handoff calls.
---
paper_title: A Novel Inter-FA Handover Scheme for Load Balancing in IEEE 802.16e System

paper_content:

As the demand for high data rate increases, load balancing across cell is highly desirable. A handover (HO) among frequency assignment (FA) may be possible for load balancing theoretically, when a serving FA is crowded to accommodate additional bandwidth request in such system as IEEE 802.16e, where the multiple FAs are possible. However, this handover is impossible in the current specification because an indication to target FA is not defined. It also requires unnecessary long scanning and network re-entry procedure. In this paper, we propose novel inter-FA handover, handover among FAs for load balancing by modifying general handover algorithm. It also satisfies HO user's quality of service (QoS) by reducing HO latency, unnecessary scanning, and network re-entry. We compare with previous HO schemes for load balancing by simulation. We show that this HO scheme can achieve significantly better performance in HO user's QoS and HO delay.
---
paper_title: Multi-service load balancing in a heterogeneous network

paper_content:

In this paper, we investigate load balancing mechanisms in heterogeneous WiMAX/WLAN network. By taking both the service characteristics of the two networks and service requirements of two kinds of applications into consideration, we distribute all streaming applications to WiMAX with preemptive service priority. Then the remaining capacities of WiMAX and the entire capacity of WLAN are utilized for serving elastic applications. Accordingly, we proposed two size thresholds based on which elastic applications are dispatched to WiMAX or WLAN. Numerical results indicate that dispatching elastic applications with smaller size to WLAN performs fair well compared with other dispatching mechanisms. It is also found that the size distribution has significant impact on the performance of load balancing mechanisms.
---
paper_title: Base Station Controlled Load Balancing with Handovers in Mobile WiMAX

paper_content:

In this paper we examine base station controlled handover based load balancing in the mobile WiMAX system and study the framework that mobile WiMAX offers for conducting load balancing and directed handovers. We also propose and evaluate a BS initiated load balancing scheme for mobile WiMAX. The simulations show that the proposed scheme can balance load efficiently within the system but also avoid the so called handover ldquoping-pongrdquo effect especially harmful e.g. for VoIP connections. We also propose an addition to the mobile WiMAX specification to distinguish load balancing based directed handovers and signal quality based rescue handovers conducted by moving terminals. This way the more important rescue handovers can be prioritized in a target Base Station.
---
paper_title: Dual Handover Procedures for FA Load Balancing in WiBro Systems

paper_content:

WiBro is defined as a subset of the IEEE 802.16 standard and is developed based on the mobile WiMAX. WiBro delivers wireless data with a high transfer rate to provide mobile broadband services. However, it is necessary to consider radio resources efficiency due to limited resources. In this paper, we propose frequency assignment (FA) load balancing algorithm in order to use resources efficiently, by controlling two types of handover procedure and scheduling. When the resource unbalancing is detected in a FA, we choose BS (base station) initiated handover or MS (mobile station) initiated handover adaptively to disperse users entering and guarantee QoS (quality of service) in real time services. The difference between call admission control (CAC) and FA load balancing scheme is that FA load balancing scheme makes the MS connect with other FAs without disconnection. The proposed algorithm shows the performance improvement which is a lot for the existing algorithm in the user acceptance and QoS in real time service.
---
paper_title: WiMAX: Standards and Security

paper_content:

As the demand for broadband services continues to grow worldwide, traditional solutions, such as digital cable and fiber optics, are often difficult and expensive to implement, especially in rural and remote areas. The emerging WiMAX system satisfies the growing need for high data-rate applications such as voiceover IP, video conferencing, interactive gaming, and multimedia streaming. WiMAX deployments not only serve residential and enterprise users but can also be deployed as a backhaul for Wi-Fi hotspots or 3G cellular towers. By providing affordable wireless broadband access, the technology of WiMAX will revolutionize broadband communications in the developed world and bridge the digital divide in developing countries. Part of the WiMAX Handbook, this volume focuses on the standards and security issues of WiMAX. The book examines standardized versus proprietary solutions for wireless broadband access, reviews the core medium access control protocol of WiMAX systems, and presents carriers' perspectives on wireless services. It also discusses the main mobility functions of the IEEE 802.16e standard, describes how to speed up WiMAX handover procedures, presents the 802.16 mesh protocol, and surveys the testing and certification processes used for WiMAX products. In addition, the book reviews the security features of both IEEE 802.16 and WiMAX. With the revolutionary technology of WiMAX, the lives of many will undoubtedly improve, thereby leading to greater economic empowerment.
---
paper_title: Handover in Mobile WiMAX Networks: The State of Art and Research Issues

paper_content:

The next-generation Wireless Metropolitan Area Networks, using the Worldwide Interoperability for Microwave Access (WiMAX) as the core technology based on the IEEE 802.16 family of standards, is evolving as a Fourth-Generation (4G) technology. With the recent introduction of mobility management frameworks in the IEEE 802.16e standard, WiMAX is now in competition with the existing and forthcoming generations of wireless technologies for providing ubiquitous computing solutions. However, the success of a good mobility framework largely depends on the capability of performing fast and seamless handovers irrespective of the deployed architectural scenario. Now that the IEEE has defined the Mobile WiMAX (IEEE 802.16e) MAC-layer handover management framework, the Network Working Group (NWG) of the WiMAX Forum is working on the development of the upper layers. However, the path to commercialization of a full-fledged WiMAX mobility framework is full of research challenges. This article focuses on potential handover-related research issues in the existing and future WiMAX mobility framework. A survey of these issues in the MAC, Network and Cross-Layer scenarios is presented along with discussion of the different solutions to those challenges. A comparative study of the proposed solutions, coupled with some insights to the relevant issues, is also included.
---
paper_title: Seamless high-velocity handover support in mobile WiMAX networks

paper_content:

The IEEE 802.16e standard (i.e., mobile WiMAX) has been proposed to provide connectivity in wireless networks for mobile users (including users at a vehicular speed). It is shown in our analysis that the probability of a successful handover decreases significantly when the user moves at a higher speed. Then, we propose a scheme that combines adaptive forward error correction (FEC) with retransmission to offer extra protection for handover signaling messages to enhance the probability of a successful handover, especially at a higher velocity. It is demonstrated by computer simulation that the proposed scheme provides a higher successful handover probability at various velocities.
---
paper_title: Efficient Authentication Schemes for Handover in Mobile WiMAX

paper_content:

Mobile WiMAX is the next generation of broadband wireless network. It allows users to roam over the network under vehicular speeds. However, when a mobile station changes from one base station to another, it should be authenticated again. This may lead to delay in communication, especially for real-time applications, such as VoIP and Pay-TV systems. In this paper, we propose two efficient schemes to enhance the performance of authentication during handover in mobile WiMAX. The first scheme adopts, instead of the standard EAP method used in handover authentication, an efficient shared key-based EAP method. The second one, skips the standard EAP method, does the authentication in SA-TEK three-way handshake in PKMv2 process. In addition, the security proofs of our schemes are provided in this paper.
---
paper_title: Fast Intra-Network and Cross-Layer Handover (FINCH) for WiMAX and Mobile Internet

paper_content:

To support fast and efficient handovers in mobile WiMAX, we propose fast intra-network and cross-layer handover (FINCH) for intradomain (intra-CSN) mobility management. FINCH is a complementary protocol to mobile IP (MIP), which deals with interdomain (inter-CSN) mobility management in mobile WiMAX. FINCH can reduce not only the handover latency but also the end-to-end latency for MIP. Paging extension for FINCH is also proposed to enhance the energy efficiency. The proposed FINCH is especially suitable for real-time services in frequent handover environment, which is important for future mobile WiMAX networks. In addition, FINCH is a generic protocol for other IEEE 802-series standards. This is especially beneficial for the integration of heterogeneous networks, for instance, the integration of WiMAX and WiFi networks. Both mathematical analysis and simulation are developed to analyze and compare the performance of FINCH with other protocols. The results show that FINCH can support fast and efficient link layer and intradomain handovers. The numerical results can also be used to select proper network configurations.
---
paper_title: A structured channel borrowing scheme for dynamic load balancing in cellular networks

paper_content:

We propose an efficient dynamic load balancing scheme in cellular networks for managing a teletraffic hot spot in which channel demand exceeds a certain threshold. A hot spot, depicted as a stack of hexagonal 'ring' of cells, is classified as complete if all cells within it are hot. The rings containing only cold cells outside the hot spot are called 'peripheral rings'. Our load balancing scheme migrates channels through a structured borrowing mechanism from the cold cells within the 'rings' or 'peripheral rings' to the hot cells in the hot spot. For the more general case of an incomplete hot spot, a cold cell is further classified as cold safe, cold semi-safe or cold unsafe, and a demand graph is constructed from the channel demand of each hot cell from its adjacent cells in the next outer ring. The channel borrowing algorithm works on the demand graph in a bottom up fashion, satisfying the demands of the cells in each subsequent inner ring. Markov chain models are developed for a hot cell and detailed simulation experiments are conducted to evaluate the performance of our load balancing scheme. Comparison with an existing load balancing strategy under moderate and heavy teletraffic conditions, shows a performance improvement of 12% in terms of call blockade by our load balancing scheme.
---
paper_title: Load balancing in overlapping wireless LAN cells

paper_content:

We propose a load-balancing scheme for overlapping wireless LAN cells. Agents running in each access point broadcast periodically the local load level via the Ethernet backbone and determines whether the access point is overloaded, balanced or under-loaded by comparing it with the received reports. The load metric is the access point throughput. Overloaded access points force the handoff of some stations to balance the load. Only the under-loaded access points accept the roaming stations in minimizing the number of handoffs. We show via experimental evaluation that our balancing scheme increases the total wireless network throughput and decreases the cell delay.
---
paper_title: Adaptive traffic-load shedding and its capacity gain in CDMA cellular systems

paper_content:

In a situation such as a traffic accident on a highway, the active mobiles in an affected cell may easily outnumber the capacity, and an excessive increase in CDMA noise may, in the worst case, block all calls in the cell if the users insist on calling through the same cell site. A scheme to alleviate such congestion in CDMA cellular systems is proposed, so that traffic load is adaptively shed from affected cells by forced hand-offs of the mobiles farthest away from current cell site. The capacity with adaptive load shedding is studied by computer simulations considering two scenarios: a single congested cell with six neighbouring cells partially loaded, and three consecutive congested cells with four neighbouring cells partially loaded. The results show that the scheme offers higher CDMA cellular capacity gain than the normal power-up control adopted by the current CDMA cellular standard.
---
paper_title: Adaptive handoff algorithms for dynamic traffic load distribution in 4G mobile networks

paper_content:

In 4G mobile networks which is a kind of packet-based cellular systems, resources are shared among all users and the amount of available resources is determined by traffic load. If traffic load is concentrated in a cell, this cell become to the hotspot cell. The hotspot cell can cause to block or drop calls and consequently degrades the service quality even though available resources are remained in neighboring cells. Therefore, it is essential to distribute traffic load of the hotspot cell in order to effectively use remained resources and maintain the acceptable service quality. We propose adaptive handoff algorithms for dynamic traffic load distribution in the hotspot cell. In the simulation, we find that these algorithms can reduce call drop rate of new and handoff calls thus enhance the service quality
---
paper_title: WLC17-4: Load-Balancing QoS-Guaranteed Handover in the IEEE 802.16e OFDMA Network

paper_content:

In this paper we propose a load-balancing QoS- guaranteed handover algorithm in the IEEE 802.16e OFDMA network. We describe our system load model for the IEEE 802.16e OFDMA network and propose the optimal and fast handover algorithms. We evaluate our fast handover algorithm using system level simulation of the IEEE 802.16e OFDMA network. Our fast load-balancing handover algorithm eliminates overloading, thus guarantees meeting the QoS requirements of the users. It also provides a considerable throughput gain over the traditional SINR-based handover algorithm.
---
paper_title: A Novel Inter-FA Handover Scheme for Load Balancing in IEEE 802.16e System

paper_content:

As the demand for high data rate increases, load balancing across cell is highly desirable. A handover (HO) among frequency assignment (FA) may be possible for load balancing theoretically, when a serving FA is crowded to accommodate additional bandwidth request in such system as IEEE 802.16e, where the multiple FAs are possible. However, this handover is impossible in the current specification because an indication to target FA is not defined. It also requires unnecessary long scanning and network re-entry procedure. In this paper, we propose novel inter-FA handover, handover among FAs for load balancing by modifying general handover algorithm. It also satisfies HO user's quality of service (QoS) by reducing HO latency, unnecessary scanning, and network re-entry. We compare with previous HO schemes for load balancing by simulation. We show that this HO scheme can achieve significantly better performance in HO user's QoS and HO delay.
---
paper_title: Load Balance for Multi-Layer Reuse Scenarios on Mobile WiMAX System

paper_content:

This paper intends to propose a novel handover algorithm to balance the load of the layers in a multi-reuse scenario. Each layer works independently from each other and it has its own scheduling process, coverage and mobile stations attached. The algorithm proposed balances the resources among layers by moving mobile stations from one to another layer according their QoS requirements and channel condition. Results show that it can increase the cell coverage and still keeping a satisfactory quality for the VoIP calls. Effective spectral efficiency also increased when comparing with single tri-sectorized reuse 1 scenario. The algorithm is also prepared to avoid ping-pong handovers and to work for any number of layers.
---
paper_title: Base Station Controlled Load Balancing with Handovers in Mobile WiMAX

paper_content:

In this paper we examine base station controlled handover based load balancing in the mobile WiMAX system and study the framework that mobile WiMAX offers for conducting load balancing and directed handovers. We also propose and evaluate a BS initiated load balancing scheme for mobile WiMAX. The simulations show that the proposed scheme can balance load efficiently within the system but also avoid the so called handover ldquoping-pongrdquo effect especially harmful e.g. for VoIP connections. We also propose an addition to the mobile WiMAX specification to distinguish load balancing based directed handovers and signal quality based rescue handovers conducted by moving terminals. This way the more important rescue handovers can be prioritized in a target Base Station.
---
paper_title: WLC17-4: Load-Balancing QoS-Guaranteed Handover in the IEEE 802.16e OFDMA Network

paper_content:

In this paper we propose a load-balancing QoS- guaranteed handover algorithm in the IEEE 802.16e OFDMA network. We describe our system load model for the IEEE 802.16e OFDMA network and propose the optimal and fast handover algorithms. We evaluate our fast handover algorithm using system level simulation of the IEEE 802.16e OFDMA network. Our fast load-balancing handover algorithm eliminates overloading, thus guarantees meeting the QoS requirements of the users. It also provides a considerable throughput gain over the traditional SINR-based handover algorithm.
---
paper_title: A new distributed uplink packet scheduling algorithm in WiMAX newtorks

paper_content:

Worldwide interoperability for Microwave Access (WiMAX) is designed to support a wide range of Quality of Service (QoS) requirements for different applications. Unlike the single service networks, a priority based mechanism is needed for specifying the transmission order of packets belonging to different traffic sources according to their QoS characteristics, which is called packet scheduling. In WiMAX standard, packet scheduling algorithm is not defined and its design is left for researchers. In this work, we propose a distributed uplink packet scheduling algorithm. In the proposed algorithm, when uplink capacity cannot satisfy the required resource of connections, according to traffic characteristics of the connection and their QoS requirement, the traffic of one or some user terminals from user terminals in the overlapping cells are selected for transferring to the neighboring under-loaded cells. The simulation results show that, the proposed algorithm increases the overall throughput of the network.
---
paper_title: Load Balance for Multi-Layer Reuse Scenarios on Mobile WiMAX System

paper_content:

This paper intends to propose a novel handover algorithm to balance the load of the layers in a multi-reuse scenario. Each layer works independently from each other and it has its own scheduling process, coverage and mobile stations attached. The algorithm proposed balances the resources among layers by moving mobile stations from one to another layer according their QoS requirements and channel condition. Results show that it can increase the cell coverage and still keeping a satisfactory quality for the VoIP calls. Effective spectral efficiency also increased when comparing with single tri-sectorized reuse 1 scenario. The algorithm is also prepared to avoid ping-pong handovers and to work for any number of layers.
---
paper_title: Multi-service load balancing in a heterogeneous network

paper_content:

In this paper, we investigate load balancing mechanisms in heterogeneous WiMAX/WLAN network. By taking both the service characteristics of the two networks and service requirements of two kinds of applications into consideration, we distribute all streaming applications to WiMAX with preemptive service priority. Then the remaining capacities of WiMAX and the entire capacity of WLAN are utilized for serving elastic applications. Accordingly, we proposed two size thresholds based on which elastic applications are dispatched to WiMAX or WLAN. Numerical results indicate that dispatching elastic applications with smaller size to WLAN performs fair well compared with other dispatching mechanisms. It is also found that the size distribution has significant impact on the performance of load balancing mechanisms.
---
paper_title: Base Station Controlled Load Balancing with Handovers in Mobile WiMAX

paper_content:

In this paper we examine base station controlled handover based load balancing in the mobile WiMAX system and study the framework that mobile WiMAX offers for conducting load balancing and directed handovers. We also propose and evaluate a BS initiated load balancing scheme for mobile WiMAX. The simulations show that the proposed scheme can balance load efficiently within the system but also avoid the so called handover ldquoping-pongrdquo effect especially harmful e.g. for VoIP connections. We also propose an addition to the mobile WiMAX specification to distinguish load balancing based directed handovers and signal quality based rescue handovers conducted by moving terminals. This way the more important rescue handovers can be prioritized in a target Base Station.
---
paper_title: Dual Handover Procedures for FA Load Balancing in WiBro Systems

paper_content:

WiBro is defined as a subset of the IEEE 802.16 standard and is developed based on the mobile WiMAX. WiBro delivers wireless data with a high transfer rate to provide mobile broadband services. However, it is necessary to consider radio resources efficiency due to limited resources. In this paper, we propose frequency assignment (FA) load balancing algorithm in order to use resources efficiently, by controlling two types of handover procedure and scheduling. When the resource unbalancing is detected in a FA, we choose BS (base station) initiated handover or MS (mobile station) initiated handover adaptively to disperse users entering and guarantee QoS (quality of service) in real time services. The difference between call admission control (CAC) and FA load balancing scheme is that FA load balancing scheme makes the MS connect with other FAs without disconnection. The proposed algorithm shows the performance improvement which is a lot for the existing algorithm in the user acceptance and QoS in real time service.
---

Title: A Survey for Load Balancing in Mobile WiMAX Networks

Section 1: INTRODUCTION
Description 1: This section introduces Mobile WiMAX, its advantages, and the challenges of providing Quality of Service (QoS) with the focus on load balancing and handover processes in mobile environments. 

Section 2: Load Balancing Process
Description 2: This section describes the general process of load balancing including the essential elements such as load definition, load measurement, and load balancing mechanisms.

Section 3: Load Definition
Description 3: This section explains the role of load metrics in load balancing algorithms and how they measure the balance state of the system in mobile WiMAX networks.

Section 4: Load Measurements
Description 4: This section covers the criteria and methods used for evaluating the load status of the system in load balancing algorithms.

Section 5: Load Balancing Mechanisms
Description 5: This section details the schemes to solve the problem in overloaded cells, divided into resource allocation and load distribution schemes.

Section 6: Resource Allocation Schemes
Description 6: This section discusses the schemes of load balancing through resource allocation, including fixed channel allocation (FCA) and dynamic channel allocation (DCA).

Section 7: Load Distribution Schemes
Description 7: This section describes the schemes of load balancing through load distribution, focusing on handover-based algorithms.

Section 8: HANDOVER IN MOBILE WIMAX
Description 8: This section gives an overview of the handover process in mobile WiMAX, highlighting its importance for balancing load and ensuring QoS.

Section 9: Types of Handover in Mobile WiMAX
Description 9: This section classifies types of handovers based on technology, structural aspect, initiation, and execution mechanisms.

Section 10: LOAD BALANCING ALGORITHMS IN WIRELESS NETWORKS
Description 10: This section provides a review of load balancing algorithms in traditional wireless networks, emphasizing resource allocation and load distribution schemes.

Section 11: LOAD BALANCING ALGORITHMS IN WIMAX NETWORKS
Description 11: This section examines existing load balancing algorithms specifically designed for mobile WiMAX networks, focusing on load distribution methods.

Section 12: CONCLUSION
Description 12: This section summarizes the survey, discussing the effectiveness of different load balancing algorithms and suggesting the best approaches for mobile WiMAX networks.