Research on Autonomous Distributed Wireless Ad Hoc Networks

自主分布式无线自组织网络是指在没有任何基础设施的情况下，由协作节点组成的自配置系统。一个关键的假设是，任何两个节点都可以直接通信或使用多跳中继。通过对物理层、媒体访问控制层、网络层等多个层次的关注，阐明了无线自组网的几个基本属性。主要研究成果总结如下：1.符号速率控制和多跳传输具有相同的扩展服务区域的能力，但吞吐量有所损失。数值结果表明，符号速率控制和多跳传输有很大的不同，只有多跳传输才能提高空间频谱效率。2.在分布式控制无线自组织网络中，如果每个节点由于相互干扰而以自私的方式寻求更好的路径和更好的吞吐量，则可能会在多条路径之间发生路径选择冲突。分析…的步骤更重要的是，博弈论被发现是有效的，并被应用于评估可实现的吞吐量。结果表明，在发射功率较低的情况下，去中心化的自适应路由选择可以获得接近容量的吞吐量。3.CSMA/CA被广泛应用于adhoc网络的媒体接入控制协议。为了满足提高网络吞吐量的需求，多信道和信道绑定技术被提出，以有效地利用多个现有的信道。数值和仿真结果表明，在低业务量条件下，信道绑定技术可以获得较低的时延，而在高业务量条件下，多信道技术可以同时提高吞吐量和时延。4.TCP被广泛认为是自组网的一种传输协议。然而，无线网络的链路质量不稳定可能导致与有线网络相比效率较低。提出了一种新的译码方法，通过利用错误包使Tornado型码对误码有效，并通过实验证实了该方法的优越性。较少

Autonomous distributed wireless ad hoc networks are self-configuring systems formed by co-operating nodes without any established infrastructure. A key assumption is that any two nodes can communicate directly or using multi-hop relaying. By paying attention to multiple layers, i.e., physical, media access control, network, etc., several essential properties of wireless ad hoc networks are clarified. Major research results are summarized below.1.Symbol rate control and multi-hop transmission have the same ability to expand the service area at the loss of throughput. Numerical results revealed a significant difference between symbol rate control and multi-hop transmission such that only multi-hop transmission can increase the spatial spectral efficiency.2.In distributed control wireless ad hoc networks, there might occur conflicts in route selection among multiple routes if each node seeks for better route with better throughput in a selfish manner due to mutual interference. To analyze … More this behavior, game theory is found to be effective and is applied to evaluate the achievable throughput. It is revealed that when the transmit power is low, decentralized adaptive route selection may attain throughput near the capacity.3.CSMA/CA is widely used for media access control protocol of ad hoc networks. In order to meet the demand to increase the network throughput, multi-channel and channel bonding techniques are proposed to effectively utilize multiple existing channels. Numerical and simulation results indicate that under low-traffic conditions, channel-bonding technique can achieve a low delay, while under high-traffic conditions, the multi-channel technique improve both throughput and delay.4.TCP is widely considered to be a transport protocol for ad hoc networks. However, instable link quality of wireless networks may result in lower efficiency compared to wired networks. A new decoding method which makes Tornado-type codes effective to bit errors by exploiting error packets is proposed and the advantage of the proposed method is confirmed by experiments. Less