MAC Protocol for Ad-hoc Multi-hop WLAN using Smart Antenna

• Main Authors: Te-Wei Ho, 何德威
• Other Authors: Wen-Tsuen Chen
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/37752952939032992914

碩士 === 國立清華大學 === 通訊工程研究所 === 93 === In ad-hoc multi-hop wireless networks, use of smart antennas can substantially increase system capacity. However, smart antenna technology leads to new channel access problems, such as Hidden Terminal Due to Unheard RTS/CTS and Hidden Terminal Due to Asymmetry in Gain. This paper proposes a MAC protocol that can solve these two problems. The proposed scheme has the following features. First, the antenna pattern used to transmit DATA differs from the antenna pattern used to transmit RTS/CTS/ACK. Second, the gain used to transmit RTS/CTS differs from the gain used to transmit DATA/ACK. Third, the nodes that receive RTS/CTS are limited according to the proposed rules. Finally, the NAV (Network Allocation Vector) timer of the proposed MAC protocol should be separated into two parts: transmitting NAV and receiving NAV. Simulation results show that the proposed MAC protocol can effectively improve network throughput, as compared to other MAC protocols using smart antennas.