采用智能天線和功率控制的adhoc網(wǎng)絡(luò)mac協(xié)議的研究

1、華中科技大學(xué)博士學(xué)位論文采用智能天線和功率控制的Ad Hoc網(wǎng)絡(luò)MAC協(xié)議的研究姓名：范軍申請學(xué)位級別：博士專業(yè)：計算機(jī)系統(tǒng)結(jié)構(gòu)指導(dǎo)教師：李之棠20080601III華 中 科 中 科 技 大 學(xué) 博 士 學(xué) 位 論 大 學(xué) 博 士 學(xué) 位 論 文 Abstract Ad hoc network is a multi-hop, packet forwarding and temporary autonoumous system of

2、mobile terminals that consists of wireless transceiver. Due to the sharing characterisitis of the wireless medium, MAC protocol becomes the key technology for the development of ad hoc network. Currently, the study in th

3、is field is still an open issue and many problems are still waiting for solution. Using smart antennas and power control technology in the study for MAC protocols for ad hoc network will greatly reduce interference, enha

4、nce transmission quality and improve network performance. However, two major problems remain unsolved on the application of smart antennas. Firstly, the directional beam of smart antennas worsens the hidden terminal, and

5、 it even introduces new problem of node deafness. Secondly, directional beam and omni-directional beam are assumed to have the same transmission gain. This limits the benefit of the enhanced transmission range of the dir

6、ectional communication. Many power control protocols are based on CSMA/CA mechanism. With the single channel, the RTS-CTS handshake cannot prevent the hidden terminal problem caused by different power level. They cannot

7、realize the target of both saving the power and improving the network capacity. Thus, it is theorically and pratically significative for us to conduct effective research in this field. The SDA-MAC protocol employs switch

8、 beam antennas based on CSMA/CA mechanism. The SDA-MAC protocol combines the RTS/CTS handshake, TDMA and directional beam. It uses RTS/CTS handshake to exchange the position of sender and receiver. The SDA-MAC protocol i

9、s suitable for single-hop envirnment, and multiple transmissions of different direction can exist in the same space at the same time without interfering with each other. The SDA-MAC protocol sloves the problems of hidden

10、 terminal and node deafness and considerabely improve the network performance. The maximum throughput of the SDA-MAC protocol is 119% of D-MAC and 307% of IEEE 802.11. The DMH-MAC protocol improves the SDA-MAC protcol, a