QoS Differentiation for IEEE 802.16 WiMAX Mesh Networking

Recently IEEE 802.16 WiMAX has attracted a lot of attention in wireless networking research and applications. To enable a flexible and cost-effective deployment, mesh networking mode is defined in WiMAX standard. In this paper, we introduce a system model of WiMAX mesh networking with the focus on entry process, frame structure, centralized and distributed scheduling. The state-of-the-art WiMAX mesh networking research is reviewed. In addition, we propose an effective QoS differentiation scheme for the IEEE 802.16 WiMAX mesh networks. Both collocated scenario and general topology are theoretically analyzed and compared. Illustrative numerical examples are presented to demonstrate the effectiveness of the proposed strategy. The impact of key parameters on the performance is discussed for differentiating multiple classes of services. Several open issues are summarized as a guideline for future topics in WiMAX mesh networking research.     

Integration of IEEE 802.11 WLANs with IEEE 802.16-based multihop infrastructure mesh/relay networks: A game-theoretic approach to radio resource management

One of the promising applications of IEEE 802.16 (WiMAX)-based wireless mesh/relay networks is to provide infrastructure/backhaul support for IEEE 802.11-based mobile hotspots. In this article we present an architecture for integrating IEEE 802.11 WLANs with IEEE 802.16-based multihop wireless mesh infrastructure to relay WLAN traffic to the Internet. The major research issues in this integrated architecture are outlined and related work is reviewed. A game-theoretic model is developed for radio resource management in this integrated network architecture. In particular, a multiplayer bargaining game formulation is used for fair bandwidth allocation and optimal admission control of different types of connections (e.g., WLAN connections, relay connections, and connections from standalone subscriber stations) in an IEEE 802.16 base station/mesh router. Both connection-level and inconnection-level performances for this bandwidth management and admission control framework are presented     

Centralized Resource Allocation for Multimedia Traffic in IEEE 802.16 Mesh Networks

The IEEE 802.16 standard provides a high degree of flexibility for setting up and operating wireless broadband networks in metropolitan environments. The standard supports numerous capabilities, including mesh topologies and multimedia communications. In this paper, we study these two features by investigating how efficiently an IEEE 802.16 mesh network can treat distributed multimedia traffic by providing differentiated quality of service (QoS). A key component of the system is the ldquoenhanced frame registry tree schedulerrdquo (E-FRTS) that provides QoS-aware resource allocation using a tree structure to prepare the creation of time frames and reduce processing requirements at the beginning of each frame. Simulation results show that distributed multimedia traffic can be efficiently supported in mesh 802.16 networks, provided efficient scheduling and a reasonable number of hops.     

A novel routing algorithm in distributed IEEE 802.16 mesh networks

In this paper, we propose a novel distributed routing algorithm for IEEE 802.16/WiMax based mesh networks. Our algorithm aims at providing routes for traffic flows with minimum end-to-end delays. Based on the underlying IEEE802.16 standard distributed scheduling mechanism, our routing algorithm is incorporated into the medium access control (MAC) layer. Each node determines the next-hop nodes for the passing flows according to the scheduling information and attempts to forward packets in the very earliest slots. In addition, a loop cancelation mechanism is proposed to avoid being trapped in path loops and thus guarantees the accessibility of our algorithm. The simulation results show that our proposal can considerably reduce the delay of traffic flows and also achieve load balance to a certain degree.     

Resource Allocation in High Data Rate Mesh WPAN: A Survey Paper

IEEE 802.15.3 High data rate wireless personal area networks (HDR WPANs) have been developed to communicate with devices within 10 m at high speed. A mesh network made up of a parent piconet and several child piconets can support multi-hop communications. Wireless mesh networks (WMNs) have been expected to be the ultimate solution for the next decade wireless networking, showing rapid progress and many new inspiring applications. The international standardization organizations formed working groups to address the problem of standardization for WMNs. These groups were the IEEE 802.15.5 (mesh extensions for WPANs),the IEEE 802.11s (mesh extensions for WLANs), and the IEEE 802.16a (mesh extensions for WiMAX). The IEEE 802.15.5 standard is the standard which defines specifications for including multi-hop functionality in the legacy 802.15.3 and 802.15.4 low data rate (LDR) WPAN networks. The impetus for a WPAN to operate in a mesh topology is to increase the network coverage without increasing the transmit power, to increase the route reliability via route redundancy, self-configuration, and efficient use of device battery life. In the case of meshed WPANs, multiple WPAN clusters compete for channel time in a shared superframe. Therefore, it is essential to determine the channel time requirements of each cluster with a certain number of devices and to determine how these clusters can compete to the shared channel time. In this paper, we investigate the different resource allocation mechanisms related to the meshed HDR WPANs for the 802.15.3 and the 802.15.5 standards. We introduce the single hop and the multi-hop IEEE 802.15.3 WPAN architectures. This is followed by the introduction of the IEEE 802.15.5 standard that provides the mesh capabilities for extending the coverage area of HDR WPANs. The current on-going research issues for resource allocation, including beacon interference, reservation collision etc., in both meshed 802.15.3 and 802.15.5 are alluded to.     

IEEE802.16中一种改进的跨层QoS调度架构设计

IEEE802委员会制定了一个解决“最后一公里”宽带无线城域网（WMAN）接入问题的全球统一标准,即IEEE802．16标准。它定义了支持多种业务类型的独立于具体物理层的MAC层和多个物理层。对于802．16系统的QoS保障,标准中详细规定了服务类别的划分以及系统的Qos框架和具体的信令交互机制,但没有规定具体的QoS调度算法,而是留给厂家设计。因此本文在IEEE802．16已有QoS调度架构的基础上,设计出一种改进的跨层QoS调度架构,并详细介绍了该构架下各功能模块的功能和具体实现方法。     

IEEE 802.16/WiMAX-based broadband wireless access and its application for telemedicine/e-health services

In this article we investigate the application of IEEE 802.16-based broadband wireless access (BWA) technology to telemedicine services and the related protocol engineering issues. An overview of the different evolutions of the IEEE 802.16 standard is presented and some open research issues are identified. A survey on radio resource management, traffic scheduling, and admission control mechanisms proposed for IEEE 802.16/WiMAX systems is also provided. A qualitative comparison between third-generation wireless systems and the IEEE 802.16/WiMAX technology is given. A survey on telemedicine services using traditional wireless systems is presented. The advantages of using IEEE 802.16/WiMAX technology over traditional wireless systems, as well as the related design issues and approaches are discussed. To this end, we present a bandwidth allocation and admission control algorithm for IEEE 802.16-based BWA designed specifically for wireless telemedicine/e-health services. This algorithm aims at maximizing the utilization of the radio resources while considering the quality of service requirements for telemedicine traffic. Some performance evaluation results for this scheme are obtained by simulations     

Design of the QoS framework for the IEEE 802.16 mesh networks

IEEE 802.16 (WiMax) technology is designed to support broadband speeds over wireless networks for the coming era of broadband wireless access (BWA). IEEE 802.16 is expected to provide transmission of high‐rate and high‐volume multimedia data streams for fixed and mobile applications. As an extension of point‐to‐multipoint (PMP) configuration, the IEEE 802.16 mesh mode provides a quicker and more flexible approach for network deployment. Multimedia networking requires quality‐of‐service (QoS) support, which demands elaborate mechanisms in addition to the four service types defined in the specification. By examining standard centralized and distributed scheduling/routing schemes in the mesh mode from QoS aspect, a BS‐controlled and delay‐sensitive scheduling/routing scheme is proposed in the paper. Associate mechanisms including admission control, flow setup and link state monitoring are also proposed. Integration of the proposed mechanisms is presented as a complete QoS framework. Simulation study has demonstrated that the average delay as well as the delay jitters per hop in the proposed scheme is smaller than that of the distributed scheme and much smaller than that of the centralized scheme. Furthermore, proposed mechanisms can also achieve higher throughput than the contrasts and generate much smaller signaling overhead, making the proposed framework a promising scheme for multimedia support in the IEEE 802.16 mesh network. Copyright © 2009 John Wiley & Sons, Ltd.     

基于IEEE802．16的无线Mesh网络的冲突改进方法

文章首先介绍了IEEE 802．16的mesh结构以及Mesh模式下协同分布式调度，对mesh结构下的三次握手机制进行了阐述，提出了原协议中三次握手机制的冲突问题，并在此基础上进行分析，针对所存在的冲突，提出了一种三次握手机制改进方法。通过分析和NS-2仿真表明，该方法性能较好，不但缩短了端到端时延，而且同时增加了吞吐量。     

Efficient routing and centralized scheduling algorithms for IEEE 802.16 Mesh Networks

An IEEE 802.16 wireless system can provide broadband wireless access to subscriber stations and operate in mesh mode. The communication between a subscriber station and a base station can pass through one or more intermediate subscriber stations. The IEEE 802.16 standard provides a centralized scheduling mechanism that supports contention‐free and resource‐guarantee transmission services in mesh mode. However, the corresponding algorithm to this schedule is quite primitive in the standard. In this paper, we propose a more efficient way to realize this schedule by maximizing channel utilization. Our designs are divided into two phases: routing and scheduling. First, a routing tree topology is constructed from a given mesh topology by our proposed tree construction algorithm. Secondly, we allocate channel resources to the edges in the routing tree by our proposed scheduling algorithm. To further support the quality‐of‐service schedule, we extend our designs by addressing some issues such as service class, admission control and fairness. Simulation results show the superiority of our proposed algorithms over others. Copyright © 2011 John Wiley & Sons, Ltd.     

Application of IEEE 802.16 Mesh Networks as the Backhaul of Multihop Cellular Networks

Cellular networks have been widely used to support many new audio-and video-based multimedia applications. The demand for higher data rate and diverse services has driven the research on multihop cellular networks (MCNs). With its ad hoc network features, an MCN can offer many additional advantages, such as increased network throughput, scalability and coverage. However, providing ad hoc capability to MCNs is challenging as it may require proper wireless interfaces. In this article, the architecture of IEEE 802.16 network interface to provide ad hoc capability for MCNs is investigated, with its focus on the IEEE 802.16 mesh networking and scheduling. Several distributed routing algorithms based on network entry mechanism are studied and compared with a centralized routing algorithm. It is observed from the simulation results that 802.16 mesh networks have limitations on providing sufficient bandwidth for the traffic from the cellular base stations when a cellular network size is relatively large.     

A Cross-Layering Design for IPv6 Fast Handover Support in an IEEE 802.16e Wireless MAN

Broadband wireless access networks, such as the IEEE 802.16 standard for wireless metropolitan area networks (WMANs), aim to provide high bandwidth, low-cost, scalable solutions that extend multimedia services from backbone networks to wireless users. Because of a larger coverage area, portability and mobility have become significant issues for providing high quality mobile services, as it is crucial to minimize handover latency and maintain IP session continuity. As a result, such issues were addressed by the IEEE 802.16e task group on the mobile WMAN. However, the scope of the IEEE 802.16e standard did not include cross-layering approaches for the enhancement of upper layer handover performance. This article proposes a new cross-layering design for fast IPv6 handover support over IEEE 802.16e. First, we describe the IEEE 802.16 deployment architectures, as well as the link layer, handover procedures in IEEE 802.16e. Next, we describe the operation of fast IPv6 handover and point out the need for interaction between the network layer and the link layer for proper performance. Then, we propose a new cross-layering design to achieve a proper behavior of the fast IPv6 handover over IEEE 802.16e. Finally, we present handover scenarios for the proposed techniques and discuss the major factors that contribute to the handover latency.     

Cross-layer Scheduling Algorithms for IEEE 802.16 Based Wireless Mesh Networks

Wireless mesh network (WMN) is emerging as an important networking architecture for future wireless communications. The mesh mode supported in IEEE 802.16 protocol provides a TDMA solution for WMN, in which scheduling is an important issue. In this paper, we discuss the issues on how to satisfy a set of bandwidth requests in IEEE 802.16 WMNs using minimal radio resources (or solving minimal schedule length problem). In consideration of transmission overhead and adaptive modulation and coding (AMC), two cross-layer scheduling algorithms are proposed, namely max-transmission and priority-based algorithms. In particular, they are proposed based on a physical interference model, instead of a protocol interference model as suggested in the literature. For the priority-based algorithm, we study several priority criteria based on different cross-layer information. An iterative scheme for QoS traffic is introduced to guarantee fairness when traffic load exceeds the network capacity. Simulation results show that our algorithms outperform the existing schemes based on protocol model, and they also ensure better fairness among different nodes.     

Dynamic frame partitioning scheme for IEEE 802.16 mesh networks

The IEEE 802.16 mesh network is a promising next generation wireless backbone network. In the network, the allocation of minislots is handled by centralized scheduling and distributed scheduling, which are independently exercised. However, the standard does not specify how the frame can be partitioned among its centralized and distributed schedulers. Through efficient partitioning that dynamically adapts the partitioning based on demand, network can support more user applications. Although a dynamic frame partitioning scheme to use Markov model has been studied, the dynamic frame partitioning method has not been fully investigated. This paper proposes two novel and general dynamic frame partitioning scheme for IEEE 802.16 mesh networks so that the minislot allocation can be more flexible and the utilization is increased. The two schemes respectively use GM(1,1)‐Markov model and Grey–Verhulst–Markov model to predict efficient partitions for future frames according to the minislot utilization in current frames. Our study indicates that the two proposed schemes outperform the scheme of using Markov model. Copyright © 2012 John Wiley & Sons, Ltd.     

Queue-aware uplink bandwidth allocation and rate control for polling service in IEEE 802.16 broadband wireless networks

IEEE 802.16 standard defines the air interface specifications for broadband access in wireless metropolitan area networks. Although the medium access control signaling has been well-defined in the IEEE 802.16 specifications, resource management and scheduling, which are crucial components to guarantee quality of service performances, still remain as open issues. In this paper, we propose adaptive queue-aware uplink bandwidth allocation and rate control mechanisms in a subscriber station for polling service in IEEE 802.16 broadband wireless networks. While the bandwidth allocation mechanism adaptively allocates bandwidth for polling service in the presence of higher priority unsolicited grant service, the rate control mechanism dynamically limits the transmission rate for the connections under polling service. Both of these schemes exploit the queue status information to guarantee the desired quality of service (QoS) performance for polling service. We present a queuing analytical framework to analyze the proposed resource management model from which various performance measures for polling service in both steady and transient states can be obtained. We also analyze the performance of best-effort service in the presence of unsolicited grant service and polling service. The proposed analytical model would be useful for performance evaluation and engineering of radio resource management alternatives in a subscriber station so that the desired quality of service performances for polling service can be achieved. Analytical results are validated by simulations and typical numerical results are presented.     

Capacity estimation and TCP performance enhancement over mobile WiMAX networks - [WiMAX update]

The mobile WiMAX system is based on IEEE 802.16e, which defines radio interface supporting several classes of Internet Protocol applications and services. While the mobile WiMAX system is being deployed, IEEE 802.16m TG is developing an amendment to the IEEE 802.16e to greatly improve the system performance, and it is focusing not only on the PHY and MAC performance but also on a level of end-to-end performance improvement that includes the scope of the network and application to embrace the strong market request and interest. To evaluate the mobile WiMAX system capacity and performance, all the aspects of performance evaluation ? from air link to application ? are required. For the network and application-level capacity and performance analysis, we first provide an overview of mobile WiMAX systems, especially of the OFDMA/TDD systems of IEEE 802.16e and then describe subscriber and application profiles that include traffic-mix ratio, data-session attempts for applications, diurnal-application traffic distribution, and the application-traffic model. Afterward, the simulation results of network- traffic characteristics and demand estimation are provided. Finally, in the last section, we provide simulation results of end-to-end application performance evaluation using the examples of VoIP and a TCP/IP performance-enhancement method that can be implemented in the mobile WiMAX MAC or MAC/IP cross layer.     

宽带无线接入标准--IEEE 802.16

IEEE802．16标准是IEEE802委员会专门为宽带无线接入制定的标准，在2002年4月正式公布，它定义了Wireless MAN空中接口规范，其中包括物理层(PHY)和媒体接入控制层(MAC)的规范。本介绍了802．16的协议结构及各层的功能，重点介绍了802．16MAC层。     

A queuing model for distributed scheduling in IEEE 802.16 wireless mesh networks

The IEEE 802.16 standard for wireless broadband networks includes the mesh mode in its specifications, where network nodes interact to deliver packets from a client to a remote destination through intermediate nodes. This paper presents a study of the capacity of IEEE 802.16 wireless networks in mesh mode by using M/G/1/L queuing model that represents each network node by incorporating the features of the standard in order to calculate the average delay and throughput in the node. An iterative method integrates the calculation results at each node, obtaining the end‐to‐end delay from any node of the mesh to the Base Station. Because of multiple hops, a node far from the Base Station may have its flows damaged. To minimize this problem, we propose a criterion for a fair distribution of resources. We show the numerical results of the model which indicate a good fit when compared with simulation results. Copyright © 2013 John Wiley & Sons, Ltd.     

On the impact of physical layer awareness on scheduling and resource allocation in broadband multicellular IEEE 802.16 systems [Radio Resource Management and Protocol Engineering for IEEE 802.16]

Multicellular networks based on the IEEE 802.16 standard appear to be very promising candidates to provide end users with broadband wireless access. However, they also pose interesting challenges in terms of radio resource management, where several design choices are not specified in the standard, intentionally left open to implementors. For this reason, we focus in this article on scheduling and resource allocation, and investigate how they could operate in a cross-layer fashion. In particular, we describe the principles of joint scheduling and resource allocation for IEEE 802.16 operating in AMC mode, and discuss the critical role played by physical layer considerations, especially intercell interference estimation and channel state awareness, in the obtained performance. This leads to identifying key open issues and possible general solutions     

Synchronous multicast and broadcast service in multi-rate IEEE 802.16j WiMAX relay network

IEEE 802.16j Mobile Multihop Relay Standard defines multi-hop relay operation in a WiMAX system. It uses a novel synchronous multicast and broadcast transmission mechanism to achieve macro diversity. With the newly introduced synchronous delivery constraint, the multicast data delivery algorithm should be designed differently to enhance system performance. This paper provides Multi-Rate Selection Algorithm (MRSA) for multicast and broadcast (MBS) data delivery. It could reduce the data distribution delay from the BS to all the RSs. Besides, we also propose the path selection algorithm to further improve the effectiveness of MRSA. Our simulation results show that using MRSA with our shortest-path path selection algorithm, the delay for data delivery in 802.16j MBS system could be greatly reduced. The proposed scheme could achieve the performance closed to the optimal solutions. To the authors’ best knowledge, this is the first research work to investigate the IEEE 802.16j multicast and broadcast problem.