Research On The QoS Assurance Method Of IEEE 802.16 Mesh Networks

As broadband wireless access technology plays an increasingly important role in people's life, IEEE 802.16 is recognized as one of the most potential broadband wireless access technology for its large coverage and offering differentiated quality of service (QoS) for several traffic and service categories. The MAC layer supports two kinds of modes, namely PMP( Point-to-Multipoint) mode and Mesh(Multipoint-to-Multipoint) mode. Compared with PMP mode, Mesh mode has some advantages such as long transmission distance, low cost, flexible network arrangement, high reliability and high throughput in multi-hop environments, which have attracted increasing interest in the theoretical research of wireless networks。Firstly, IEEE 802.16 stardand is introduced, which focuses on frame structure, handshaking mechanisms and the MSH-DSCH message format under IEEE 802.16 Mesh mode. Secondly, this paper introduces some basic concepts and the related study of QoS, in which the current research status of QoS in IEEE 802.16 networks is discussed in detail.Thirdly, in IEEE 802.16, a three-way handshaking mechanism is given to reserve the slots hop-by-hop for mesh networks, which is called hop-by-hop Bandwidth Reservation Protocol (HBRP). However, HBRP has large signaling overhead and longer end-to-end delay. According to the analysis of IEEE802.16 networks above, this paper will mainly research on two problems below.1) A multi-hop QoS assurance method in IEEE 802.16 Mesh networks. In this paper, we provide a QoS assurance method in IEEE 802.16 Mesh networks, Multi-hop Bandwidth Reservation Protocol (M-HBRP). After receiving MSH-DSCH.Req from its upstream node, any node in the given path will send MSH-DSCH.Req to its downstream node in the meanwhile of replying MSH-DSCH.Grant to its upstream node. The simulation results show that M-HBRP is more effective than HBRP in the existing mesh networks at both the end-to-end delay and the throughput.2) An End-to-End QoS assurance method in IEEE 802.16 Mesh networks. As it is described above, however, HBRP can not assure the End-to-End QoS, and can not optimally schedule the idle slots. In this paper, we provide a QoS assurance method in IEEE 802.16 Mesh networks, End-to-End Bandwidth Reservation Protocol (EBRP). EBRP includes End-to-End optimal bandwidth calculation and End-to-End resource reservation. The performance analysis and NS simulation show that the EBRP is more effective than HBRP in the existing Mesh networks.