QoS routing and medium access control in ultra-wideband wireless communications networks

超宽带（UWB）是一种新兴的无线通信技术，具有高速率、低传输功率、抗多径传播、精确定位等独特的潜在优点。它被认为是短距离室内和室内外无线通信中最有前途的候选者之一。人们期望超宽带无线网络能够支持多种业务并存的多媒体业务。然而，业务的多样性导致需要在网络中提供异构的服务质量（QoS）。由于有限的传输功率、用户移动性、敌对信道条件、短距离和高速率传输、其他共存系统的干扰以及对计算复杂性和系统开销的严格限制，这是一项非常具有挑战性的任务。超宽带无线技术作为一项相对较新的商业应用技术，已经投入了大量的研发工作，其中大部分集中在物理层的超宽带传输问题上。最近，由于高效和有效的路由和介质访问控制（MAC）机制对于满足QoS和高网络资源利用率至关重要，因此人们越来越关注UWB网络高层协议和算法的设计。考虑超宽带传输特性的跨层设计是一种很有前途的方法。提出的研究将侧重于1)在多址、减少开销、分组调度和QoS提供途径中开发有效的MAC协议；2)利用超宽带的定位能力，开发满足QoS要求、适应用户移动性和业务负载变化的超宽带移动自组网路由方案；3)研究协议栈之间的垂直耦合，使链路层和网络层的资源分配算法能够适应无线信道的动态变化以及UWB传输和用户应用的特点，在QoS支持和高资源利用率之间实现更好的权衡。

Ultra-wideband (UWB) is an emerging wireless communication technology with unique potential merits such as high rate, low transmission power, immunity to multipath propagation, and capability in precise positioning. It has been considered as one of the most promising candidates for short range indoor and indoor-to-outdoor wireless communications. It is expected that UWB wireless networks should be capable in supporting multimedia traffic which presents coexistence of diverse services. However, the diversity of services results in the need for provisioning heterogeneous quality of service (QoS) in the networks. This is a very challenging task because of the limited transmission power, user mobility, hostile channel conditions, short range and high rate transmission, interference from other co-existent systems, and stringent constraints on computational complexity and system overhead. As a relatively new technology for commercial applications, significant R&D efforts have been devoted to UWB wireless technologies, most of which focus on UWB transmission issues at the physical layer. More recently, there is increasing attention to the design of protocols and algorithms at the UWB network higher layers since efficient and effective routing and medium access control (MAC) mechanisms are essential to QoS satisfaction and high network resource utilization. One of the promising approaches is the cross-layer design which considers the UWB transmission characteristics. The proposed research will focus on 1) development of an efficient MAC protocol in the avenue of multiple access, overhead reduction, packet scheduling, and QoS provisioning; 2) development of a routing scheme for UWB mobile ad hoc networks, which should ensure QoS satisfaction and adapt to user mobility and traffic load variations, taking advantage of the positioning capability of UWB; 3) investigation of the vertical coupling between the protocol stacks, so that the resource allocation algorithms at the link and network layers can adapt to dynamics of the wireless channels and characteristics of UWB transmission and user applications to achieve a better tradeoff between QoS support and high resource utilization.