Cross-Layer Optimization And Performance Evaluation Of Ultra Wideband Networks

Ultra wideband (UWB) is an emerging technology and attracts a lot of attentions lately, since Federal Communications Commission assigns its spectrum from 3.1 to 10.6 GHz in 2002. It provides several hundred mega bits/sec capacity and targets at connecting multimedia and entertainment devices in a personal area. Moreover, UWB is also a replacement of littery wirelines among PC and its periphery. IEEE formed its 802.15.3a task group to standardize UWB technologies, and currently there are two competing camps, UWB forum (DS-UWB) and multi-band OFDM alliance (MBOA). As a developing technology, UWB brings many new features, such as pi-conet-based topology, mixed time-division multiple access (TDMA) and carrier sense multiple access with collision avoidance (CSMA/CA) channel access method, etc. Due to the huge interaction among multiple layers in wireless networks, the funder-mental change in MAC layer will affects other layers. Therefore, it is difficult to apply current performance analysis and optimization technologies in UWB networks. Under such background, this dissertation focuses on the challenges brought by UWB tech-nologies, especially the MAC and upper layers, and tries to propose solutions to meet such challenges. As a result, this dissertation optimizes the throughput of UWB net-works from a cross-layer point of view, and evaluates the performance of beacon pe-riod contractions in current drafts. The major contributions of this dissertation are summarized as follows:1. This dissertation optimizes UWB network from a joint topology formation and routing selection point of view, and give a non-linear programming formula-tion of the cross-layer optimization in UWB networks. Based on my understanding of UWB technology, I argue that the MAC layer and network layer must be jointly considered to achieve better performance in UWB net-works. This argue-point is validated through a simple and typical network configura-tion in the dissertation. This dissertation define the cross-layer optimization problem as: given a spatial distribution of UWB devices and some traffic requirement, find paths and form piconets to maximize the network throughput. Although there have been several works considering the problem of finding paths to achieve the optimal throughput in wireless ad hoc networks, to the best of my knowledge, none of them takes the topology formation into consideration. In this paper, we use Boolean matri-...