【作者】 康凯；

【导师】 郭伟； 吴诗其；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2005， 博士

【摘要】 无线多跳网是一种由移动节点组建的自组织网络。无线多跳网可以在不需要任何预设网络基础设施支持的情况下,只依靠自身建立起一个独立、完整的移动网络,为高度机动环境下的移动用户提供通信支持。本文中,我们主要对无线多跳网中多址和路由选择的相关技术进行了研究。 无线多跳网中,使用CDMA方式可以有效降低单一信道上隐藏终端问题对分组传输的影响。第2章中,我们对此提出了两种新型非线性多址序列设计,即“平衡相控序列”（BPC序列）和“基于No序列构造的相控序列”（NPC序列）。其中,NPC序列是对BPC序列构造的一个推广,通过选择一个周期为2ⁿ-1的No序列族和周期为2^n/2+1相位序列的循环移位,可以构造出一族2^n/2(2^n-2+1)个NPC序列。与已有的多种非线性序列相比,NPC序列族可以提供数量更多的具有平衡性和良好相关特性的多址序列,其相关界与同周期的Gold序列相近。从而对于无线多跳网中静态的多址序列分配策略,可以容纳更多数量的移动节点,对于动态分配策略,降低了对拓扑控制的要求,允许网络结构具有更好的连通性。 传输调度的设计是TDMA无线多跳网中的一个重要而复杂的问题。传输调度设计是为网络中的节点分配传输时隙,实现节点之间分组的无碰撞传送,同时获得尽可能高的时隙空间重用性。第3章中,我们提出了一种新的传输调度算法,称为“碰撞避免的正确稳健调度”（CA-PRS）算法。与以往正确稳健传输调度（PRS）算法的一个显著的区别是,CA-PRS算法中为每一条链路分别指定了一个传输调度,根据网络的拓扑变化,自适应调整对传输时隙的使用,可以实现在共享无线信道上分组传输的碰撞避免。我们还分析了算法中队头阻塞问题产生的原因,通过采用多输出排队的缓存结构和适当的分组调度方式加以消除。CA-PRS算法实现简单,协议开销小,而且克服了C-PRS算法中对节点最大度数的约束条件,适用于拓扑动态变化的无线多跳网中。 无线资源受限是无线多跳网中的一个重要特性。对于无线资源的使用,我们总是希望对它进行优化。第4章中,提出了一种无线多跳网中分布式的动态时隙分配算法,称为“可迁移的正确稳健调度”（M-PRS）算法。M-PRS算法中,利用阈值设置把节点划分为重载、中载和轻载三种类型。节点之间通过分更多还原

【Abstract】 Wireless multihop network is the self-organized network architecture, which is composed of mobile nodes. Wireless multihop network can be deployed instantly and provides network communications for highly mobile users, without the need of any pre-established infrastructures. This dissertation is dedicated to researches on some key techniques of multiple access and routing for wireless multihop networks.In wireless multihop networks, the effects of hidden terminals on the single common channel can be greatly reduced by using CDMA techniques. In chapter 2, we presented two families of nonlinear multiple access sequences, namely BPC sequence (Balanced Phase Controlled sequence) and NPC sequence (No-based Phase Controlled sequence). NPC sequence is a generalization of construction of BPC sequence. On the base of a No sequence family of period 2n-l and the cyclic shift of a phase sequence of period 2n/2+1, a family of 2n/2(2n/2+1) NPC sequences can be constructed. Compared with some typical nonlinear sequences, NPC families can provide much more sequences, with 0-1 balance and good correlation. Their correlation bound is similar to Gold sequences of the same period. With the use of NPC families, much more mobile nodes can be contained in wireless multihop networks, for the static allocation strategy of multiple access sequences; and requirement of topology control can be reduced for the dynamic strategy, so that better connectivity is permitted.Transmission schedule to ensure good system performance is an important and complex issue for TDMA wireless multihop networks. The purpose of the transmission schedule is to allocate the transmission slots for mobile nodes to provide the contention-free packet transmission and maximize the spatial reuse of time slots. In charpter3, a new transmission scheduling algorithm, so called as CA-PRS (Collision Avoidance Proper Robust Schedule) algorithm, is presented. A distinguished difference from traditional PRS is that, CA-PRS algorithm specifies a unique transmission schedule for each link, and adjusts the slot assignments in response to dynamic topology changes, to avoid contention for packet transmissionover the shared wireless medium. The problem of head-of-line blocking in CA-PRS algorithm is also analyzed, and the degradation of performance caused by head-of-line blocking can be eliminated by using virtual queuing policies with certain packet scheduling. The algorithm proposed has some properties, such as low protocol overhead, simple and easy to implement, and eliminate the requirement of the maximum nodal degree in C-PRS algorithm, and all these make it suitable for the network environment of highly mobility.The limitation bandwidth is a basic characteristic for wireless multihop networks. How to make the optimal use of wireless resource is always an attractive topic for such network architectures. In chapter 4, we developed a novel dynamic slot scheduling algorithm, referred as M-PRS (Migratory Proper Robust Schedule) algorithm. In this method, nodes in the network are divided into three categories by using the threshold strategy, such as light-load, middle-load and heavy-load nodes. By using the distributed message communication mechanism, mobile nodes in the network can dynamically reallocate transmission slots, so that some certain slots assigned to light-load nodes can be transferred to heavy-load nodes, to alleviate the congestion on them. A judgment criterion of the migration slots is also given to reduce the collision in packet transmission. Simulation results reveal that, M-PRS algorithm has the advantages over non-migratory CA-PRS algorithm with more flexible sharing of channel resources, and effective improvement of the system throughput.Routing is an actively research area related to wireless multihop networks. The development of the efficient routing protocol is essential if wireless multihop networks need to meet the demands for higher data rates within the limited amount of the available radio bandwidth. In chapter 5, a novel multiple-path table-driven routing protocol for wireless multihop networks, referred as M-WRP (Multipath Wireless Routing Protocol) is presented. M-WRP protocol introduces the multiple-path routing mechanism to WRP, and establishes multiple paths with equal distance between source and destination pairs, so as to provide the possibility of routing optimization. A criterion of selection in forwarding paths, based on the metric of "Minimum Path Average Hop" is also given, to achieve load balance and更多还原