Reliable Multicast Retransmission Scheme In IEEE 802.16 Networks And TSCD Scheme In Mesh Mode

Nowadays, science and technology are developing rapidly. In communication area, with wireless communication playing more and more important role, BWA (broadband wireless access) technology which is an important part of wireless communication technology also has extensive applied foreground and huge development potential. IEEE 802.16 which is a kind of BWA technology is used in WMAN (Wireless Metropolitan Area Networks). It is used for solving "the last one kilometer" communication requirement. IEEE 802.16 can provide BWA with more wide area and higher rate. Especially in area where there is a lack of basic infrastructure, IEEE 802.16 as one wireless access technology will be more flexible. Initially, the 802.16 standard is for fixed broadband wireless access, and the application is restricted in a way. Now, the 802.16e standard increases the support for mobility, so it will provide more application. Because IEEE 802.16 has a lot of technical advantages, it has received much attention from people and it has become a research hotspot. The multicast technology in wireless communication environment also receives more and more attention because of its extensive applied foreground.In the thesis, 802.16 protocols are introduced. Then the multicast implement scheme and the scheduling scheme in mesh mode are explained.Then a reliable multicast retransmission scheme in 802.16 OFDMA systems is proposed because there is no ARQ scheme in 802.16 multicast services. And the simulation of the scheme is implemented, which seems that the scheme can guarantee the multicast services' integrity and QoS.And we propose a flexible two-radio and single-radio combined deployment (TSCD) scheme for multi-channel transmission using interference free scheduling algorithm in IEEE 802.16 mesh networks. The simulation results show that the proposed scheme increases the overall throughput and reduces delay of the network compared to all single-radio networks. What's more, TSCD network gets almost the same performance compared to all two-radio networks with less cost.