| 摘要: |
| 针对稠密部署ad hoc 网络中暴露节点问题引起的网络空间利用率低、吞吐量下降的问题,提出一种包侦听多路接入/冲突避免(packet sensing media access with collision avoidance,简称PSMA/CA)MAC 协议.在PSMA/CA协议中,节点通过信道侦听和邻近节点集交换获取两跳范围内邻近节点信息,暴露节点在发送数据之前,首先侦听网络中当前会话,得到会话双方地址,根据两跳范围内邻近节点信息计算当前会话与欲建立会话之间的关联度,当会话关联度小于信噪比要求时,允许暴露节点建立会话.PSMA/CA 协议允许满足条件的暴露节点建立并行会话,以提高网络空间利用率.仿真结果表明,与802.11DCF 相比较,PSMA/CA 协议下平均网络吞吐量增加20%.与其他针对暴露节点问题提出的算法相比较, PSMA/CA 不需要节点间同步,对现有无线网络硬件设备也没有提出新的要求,具有更强的适应性. |
| 关键词: ad hoc 网络 暴露节点问题 IEEE 802.11DCF PSMA/CA(packet sensing media access with collision avoidance) |
| DOI： |
| 分类号: |
| 基金项目:Supported by the National High-Tech Research and Development Plan of China under Grant No.2005AA121130 (国家高技术研究发展计划(863)) |
|
| High Throughput MAC Protocol for Static Ad Hoc Network |
|
ZHANG Ke-Wang,ZHANG De-Yun,JIANG Wei-Hua
|
| Abstract: |
| Efficient usage of available capacity is critical for ad hoc network with limited bandwidth. Capacity iswasted due to exposed terminals in high-density ad hoc network. This paper proposes a new scheme, Packet SensingMedia Access with Collision Avoidance (PSMA/CA) to solve the exposed terminals problem in static ad hocnetwork, thereby to improve the spatial reuse of the medium and increase the network throughput. Neighbors’information within 2 hops plays an important role in PSMA/CA, and the protocol act like 802.11DCF in the absence of neighbors’ information. Nodes in the network get neighbors’ information within 1-hop and 2-hops via channellistening and neighbors information exchanging respectively. Having the 2-hops neighbors’ information, an exposedterminal captures a frame of ongoing dialogue and calculates the correlation coefficient between the primarydialogue and new dialogue to be built before trying to transmit. If the correlation coefficient is lower than the
threshold required by SINR (signal to interference and noise ratio) for a certain bandwidth, the exposed terminal cancommunicate with its destination in parallel with the primary dialogue. PSMA/CA solves the exposed terminalsproblem without nodes synchronization and without additional requirements for hardware complexity. Simulationresults show that the average throughput of PSMA/CA outperforms 802.11DCF by 20% in high-density ad hocnetwork. |
| Key words: ad hoc network exposed terminals problem IEEE 802.11DCF PSMA/CA (packet sensing media access with collision avoidance) |
