Research On Multicast Error Control Protocols For Wireless Mesh Networks

Due to the rapid development and wide use of the wireless networks, various multicast applications restricted by low transmission time and strict error control are increasing. Because of the changing bandwidth, heterogeneous terminals and high packet loss rate, the wireless networks put forward new requirement for the design of network architectures and protocols. The error control schemes with better performance will further improve multicast efficiency and meet the demands of complicated network applications.The wireless mesh networks (WMN) is a new type with good prospects among the next-generation wireless networks. WMN changes many aspects of wireless local area networks (WLAN) in the inferior position with large area network coverage, rapid deployment, non line of sight (NLOS) transmission, high robustness and flexibility.The researches of error control schemes for the current wireless networks are mostly concentrated on the application layer. The inherent delay caused by the high level of the protocol can not be solved by improvement of its own theory. Thus, the researches of this paper are focusing on coordination mechanism in the media access control (MAC) layer which proposed a reliable solution of the multicast error control for WMN based on the MAC layer scheme of WLAN. The main works of this paper are as follows:1) In this paper, the structure and characteristics of WMN are carefully studied. Also it made fully investigations on the multicast error control mechanisms for the wireless networks based on the IEEE 802.11 standard MAC layer protocols of WLAN. The advantages and disadvantages of different error control protocols are elaborated and a feasibility analysis of their abilities for the applications in WMN is discussed.2) A new multicast error control protocol for the MAC layer in WMN named layer-divide beacon driven leader based protocol (Layer-BLBP) is proposed. One single round multicasting is divided into sub-layers by each hop where a leader is selected in each sub-layer. The Layer-BLBP uses acknowledge frames and non-acknowledge frames (ACK/NACK) feedback and collision to ensure reliability of multicasting and sub-layer coordination to enhance the performance. Theoretical analysis and simulation results show that Layer-BLBP is reliable for multi-hop multicast in WMN.3) Some detail issues for Layer-BLBP are discussed by cooperating with other layer's schemes, especially the unnecessary retransmission problem and the leader selection problem. Attentive analysis and simulations were made for these issues. Future research directions were also mentioned.