【作者】 刘军；

【导师】 郭伟；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2007， 博士

【摘要】 无线自组网是由一组带有无线收发装置的移动节点组成的，无需基础设施支持的动态可重构的多跳自组织网络，具有分布式、自组织、自配置、自管理等特征。能够在不能或不便利用现有网络基础设施的情况下提供一种通信支撑平台，从而拓宽了移动通信网络的应用场合。可广泛应用于国防战备、抢险救灾、应对突发事件等无法得到有线网络支持或只是临时需要通信的环境，是下一代网络的重要组成部分。本文主要研究了以下几方面内容：可自适应切换工作方式的自组网MAC协议；自组网MAC协议退避算法的改进；基于路径稳定性的按需单径路由；基于路径生存时间和业务流分配的多径路由；基于地理位置信息的路由。基于分组单次成功发送／碰撞持续的时间和当前信道冲突概率，给出了以最小化分组传输时间为优化目标的最优RTS门限计算公式。通过估计当前信道数据分组发送的冲突概率实现了最优RTS门限的计算。基于最优RTS门限的计算方法设计出了一个分布式自适应RTS门限调整算法。仿真结果验证了本文的理论分析和RTS门限调整算法的正确性。从成功传送单个比特所需的平均时间代价来看，无论是在802．11b还是802．11g局域网仿真场景中，自适应门限调整方式都明显优于单纯的RTS方式或基本方式，因此本文所介绍的自适应RTS门限调整算法能够有效优化现有无线局域网标准802．11b／g的传输性能。提出了一种新的MAC协议退避算法DDCF。提出了算法的理论依据，建立了算法的理论模型，对算法进行了仿真，比较了DDCF与DCF、BDCF和GDCF算法的性能，通过对DDCF算法的理论分析和仿真试验表明，由于DDCF算法使竞争节点获得的竞争窗口的稳态值接近理想稳态值，从而提高了系统的性能。在考虑单链路t-时间维持概率的基础上，提出了一种基于路径t-时间维持概率的路由协议THP-AORP，THP-AORP协议选择具有最大t-时间维持概率的路径，减小了链路断裂的概率。仿真结果表明THP-AORP路由协议的性能优于传统AODV路由协议和DSR路由协议。提出了一个基于路径生存时间和流量分配的多径路由算法LFD-MR。与传统的多径路由算法MSR相比，所提出的LFD-MR多径路由算法由于使用了生存时间更长的路径和多径流量分配，从而可以减小分组的平均端到端时延，提高网络吞吐量和分组的成功接收率，减小路由开销等。提出了一种基于子域滑动的分级位置管理策略SM-DHLM，SM-DHLM位置管理策略通过对网络节点进行分布式分级和子域滑动的方法减少了节点移动到子域之外的概率，并且将位置更新消息尽量限制在较小的低级子域之内，减小了位置管理的开销，提高了网络的规模可扩展能力。最后对全文进行了总结，回顾了前面所述的研究工作，并根据目前的情况对未来的研究方向作了展望。更多还原

【Abstract】 Wireless self-organizing network, which consist of a group of mobile nodes equipped with transceivers, is a dynamic reconstructable multi-hop network without the support of fixed infrastructures and has some characteristics such as distributed, self-organizing, self-configuring, self-managing, and so on. Wireless self-organizing network can afford a communication platform if the existing networking infrastructure can’t be used. It expands the using of mobile communication networks and can be used widely in tactical communication, emergency search-and-rescue operations, meetings or conventions. Wireless self-organizing network is an important component of the next generation network （NGN）. The dissertation mainly does research on the following content: the MAC protocol of wireless self-organizing network that can switch the work manner adaptively, the improvement of back-off algorithm of MAC protocol, the path stability based on-demand single-path routing, the lifetime and flow dispatch based multipath routing, and the geographic location information based routing.Based on the time duration of single successful packet transmission, the time duration of single failing packet transmission and the current collision probability of channel, the formulas of the optimal RTS threshold are given out, which aim to minimize the time overhead of packet transmission. The optimal RTS threshold is calculated by estimate the current collision probability P_c of channel. An adaptive RTS threshold adjustment algorithm is presented based on the calculating method of the optimal RTS threshold. Simulations validated the correctness of the adaptive RTS threshold adjustment algorithm. From the aspects of the time overhead of MAC frames and the transmission efficiency of 802.11 DCF, the performance of adaptive RTS threshold adjustment algorithm is better than that of the RTS access mode and the basic access mode, and it adapts to saturation state and non-saturation state. So the adaptive RTS threshold adjustment algorithm presented can effectively optimize the performance of IEEE 802.11 DCF.A DCF algorithm based on dynamic threshold, named DDCF （Dynamic threshold based DCF）, has been presented. The theoretic basis of algorithm was given out and the theoretic model was established. The algorithm was simulated and the performance of DDCF, DCF, BDCF, and GDCF are compared. By theoretic analysis and simulations, it shows that because DDCF make the static value of contention window of nodes near the ideal value, so it promoted the overall system performance. DDCF can be realized base on DCF by suitable selected threshold serial G（i） without big modification. Compared with GDCF, DCF has the adaptive adjust ability according to the number of contention nodes.An on-demand routing protocol, named THP-AORP （Time-t Path Holding Probability Based Ad-hoc On-demand Routing Protocol）, based on the analysis of the time-t holding probability of single link (P_m,n（d（m,n）,t）), has been presented based on the time-t holding probability of a whole path (Ψ_S,D（t）). New protocol chooses the path that has the maximal time-t holding probability (Ψ_S,D（t）) as the best routing. Simulations show that, compared with AODV and DSR, new protocol saved the overhead of protocol, and reduced the end-to-end delay of packet.A multipath routing algorithm, named LFD-MR （Lifetime and Flow Dispatch based Multipath Routing）, is presented. Compared with traditional MSR, being used long lifetime path and congested degree based multipath flow dispatch method, LFD-MR can decrease the average end-to-end delay of packet, promote the network throughput, increase the successful packet rate, and decrease the routing overhead.A novel location management scheme named SM-DHLM （Sub-zone Moving Distributed Hierarchical Location Management Scheme） has been proposed, Through distributed hierarchy and sub-zone moving, SM-DHLM decreases the probability of the nodes crossing the boundary of sub-zones, limits the location update messages into smaller sub-zones, decreases the overhead of location management, promotes the scalability of networks. Compared with the fixed Hierarchical Location Management Scheme, SM-DHLM has similar query success rate, has similar successful packet rate, has lower protocol overhead, and has lower average end-to-end delay.Finally, chapter 7 summarizes the dissertation, reviews the above research work and presents the future research directions.更多还原