摘要:
车载自组网(vehicular ad hoc network, VANET)中的分布式TDMA方法通常多出没有被节点利用的空闲时隙，未能充分利用无线信道资源，且不能避免由于信道条件差所导致的丢包现象.与此同时，协助通信近年来引起了学术界和工业界的广泛关注，该方法利用了无线信道的广播特性，能够有效地修复信道，提高无线通信的可靠性.针对VANET应用场合，提出了一种MAC层数据协助重发方法，即协助分布式TDMA方法(cooperative distributed TDMA, Co-DTDMA).在Co-DTDMA中，如果源节点未成功发送数据，则附近的邻居节点利用未分配的空闲时隙协助重发源节点数据.与传统的协助通信方法不同，Co-DTDMA中的所有操作都以分布式方式进行，不依赖任何中心控制节点，因而适应于VANET应用场合.此外，Co-DTDMA仅利用未分配的空闲时隙协助重发数据，不影响网络中的正常数据传输.理论分析和仿真实验表明：Co-DTDMA显著地提高了数据成功接收概率，降低了数据传输时延.
Abstract:
The distributed TDMA approach for vehicular ad hoc network (VANET) does not take advantage of idle slots, failing to effectively utilize radio resources, and the approach is not free from packet dropping due to a poor channel condition. Cooperative communication, on the other hand, has drawn significant attention from both academia and industry in recent years, since it can be effective in mitigating wireless channel impairments by utilizing the broadcast nature of the wireless channel. In the paper, a cooperative scheme for medium access control (MAC), referred to as cooperative distributed TDMA (Co-DTDMA) is presented for VANET. In Co-DTDMA, neighboring nodes utilize unreserved slots for cooperatively retransmitting a packet which has failed to reach the destination node owing to a poor channel condition. Different from traditional cooperative approaches, all Co-DTDMA operations, such as synchronization among nodes, reserving a time slot, cooperation decision and cooperative transmission are done in a fully distributed manner, which makes it suitable for VANET. In addition, cooperative transmission is conducted in unreserved slots, without interrupting the normal transmission. Both theoretical analysis and experimental results demonstrate that the proposed scheme significantly increases the probability of successful packet transmission and decreases the delay of packet transmission in various network parameters.
百度学术
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