【作者】 刘伟；

【导师】 刘洛琨；

【作者基本信息】 解放军信息工程大学 ， 军事通信学， 2011， 硕士

【摘要】 超宽带技术由于其高速率、低功耗、低成本、抗干扰、低截获概率等优点受到人们的关注,并成为近年来通信领域的研究热点之一。目前国内外对超宽带技术的研究大多关注其高速率、低功耗的优点,主要集中在短距离小范围应用领域。然而,超宽带抗干扰、强穿透能力和低截获概率等特点使其在军事通信、反恐维稳、赈灾搜救、透视探测等领域的应用需求越来越旺盛。在此种应用环境下,对超宽带通信技术的需求不只局限在短距离通信范围内,还要求超宽带拓展其传输距离并进行多跳组网,以加大覆盖范围。随着通信距离的拓展及网络规模的增大,除物理层需要新的传输技术之外,原有的短距离超宽带组网协议也将难以适用。本文围绕拓展距离超宽带组网协议展开研究,主要研究内容与创新点如下:1.针对多跳环境下隐藏节点间的信道时隙资源预留冲突问题,基于ECMA-368标准提出适合拓展距离超宽带多跳组网应用的分布式预留冲突避免机制。该机制借鉴ECMA-368MAC协议分布式预留的思想,通过增加一种新的扩展DRP可用性IE,采用多跳反馈式预留协商流程,从而避免多跳网络中3跳隐藏终端预留冲突问题,增强了网络移动性支持,提高了移动多跳网络的吞吐量。此外,为解决预留冲突产生时预留中断的随意性问题,该机制定义了新的DRP控制字段,采用区分优先级的逐级判定式预留冲突处理方法,在发生冲突时可确保实时数据传输的优先接入,适合音、视频业务较多的拓展距离超宽带的多跳移动网络环境。并通过仿真验证了其有效性。2.针对基于最小跳数传统路由算法应用于ECMA-368标准超宽带网络所带来的信道时隙占用过多、信道资源浪费问题,提出一种综合考虑端到端错包率和时隙占用总数的路由度量,并结合一种基于包串音感知的速率分配近似算法,提出一种超宽带路由及速率分配联合算法。该算法在路由寻找的同时结合速率分配算法为每条路径中的链路分配近似最佳传输速率,并基于综合路由度量在多条已分配链路传输速率的路径中进行选择。其所获得的路径可在满足端到端错包率的前提下,在信道时隙占用数量的意义上达到近似最优,从而较传统的最小跳数和最短距离路由(DSR,GPSR)更加节省信道时隙占用,具备更大的网络吞吐量。并通过仿真验证了算法的有效性。3.对于在速率分配机制中所应用到的包串音感知机制,研究发现其应用不仅局限于此,在数据包的中继转发中还可对其进一步开发利用。对此本文给出一种利用包串音的中继转发策略,采用多点联合转发的方法,可提高转发的可靠性。同时给出一种包串音转发时间的利用方法,使目的节点广播其收到的串音数据包,避免串音数据包的重复转发,进一步节省信道时隙占用。本论文提出的拓展距离超宽MAC协议改进机制已在相关课题中得到了应用。更多还原

【Abstract】 The Ultra-Wideband (UWB) technology recently attracts people’s attention and becomes a research focus in wireless communication domain due to its advantages of high data rate, low power consumption, low cost, anti-interference and low interception rate. The recent domestic and abroad research on UWB technology mostly focus on its advantages of high data rate and low power consumption, witch makes the application of UWB localized in short distance application domain. However, the advantages, such as anti-interference and low interception rate, of UWB technology makes the requirement of it more and more intense on the application of military communication, anti-terrorism, relief rescue, perspective detection and other special fields. Under these circumstances, the requirement of UWB technology asking it to extend its transmission distance and construct multi-hop network to increase coverage. With the extension of communication distance and the increase of network scale, in addition to the physical layer need new communication technology, the traditional network protocol of short distance UWB will also difficult to apply.This thesis does some further research on extended distance UWB network protocol, with the main content and innovation as follows:1. Aiming at the reservation conflict problem of channel slots between hidden nods under the circumstances of multi-hop, a new DRP collision-free mechanism based on ECMA-368 which is suitable for the extended UWB multi-hop network is proposed. This mechanism takes the thought of distributed reservation of ECMA-368MAC for reference. It can avoid 3-hop reservation conflict and increase the network throughput by adding a new extended DRP available IE and using a new multi-hop feedback distributed reservation negotiation process. Moreover, aiming at the randomness of the reservation termination when a reservation conflict occur, the proposed mechanism define a new DRP control field and adopt a method of prioritized DRP conflict resolution process so that in can guarantee the access priority of real time date transmission when reservation conflict appears. This mechanism is appropriate for the multi-hop and mobile environment of the extended UWB network with more load of audio and video business. The results of simulation illustrate the effectiveness.2. Aiming at the problem of occupied too many channel time slots and waste of channel resource when the traditional min-hop routing algorithm apply in the ECMA-368 standard UWB network, a UWB routing and rate assignment algorithm is proposed. This algorithm use a new routing metric, which taking the end-to-end PER and the total number of slots into consideration, and a new rate assignment approximation algorithm, which based on the perception of packet overhearing.This algorithm can obtain the path and the optimal transmission over it, which can make the slots occupied by the path minimized when satisfying the end-to-end PER constrain. So it can provide greater network throughput than the traditional DSR and GPSR. The results of simulation illustrate the effectiveness of this proposed algorithm.3. The further research found that the packet overhearing mechanism used in the rate assignment approximate algorithm can undertake further exploitation in the process of packet relaying. This thesis gives a method of reliable relaying, which based on the principle of packet overhearing. This method can improve the reliability of packet relaying. Meanwhile, this paper gives a method of exploiting the relaying time of overheard packets, which can avoid the overheard packets being repeatedly relayed and reduce the occupation of slots ulteriorly.The improving scheme of the MAC protocol of the extended UWB network proposed in this thesis has been applied in corresponding project.更多还原