Exploiting Diversity in Broadband Wireless Relay Networks
Qingxiong Deng · Digital WPI · 2012
Fading is one of the most fundamental impairments to wireless communications. The standard approach to combating fading is by adding redundancy- or diversity- to help increase coverage and transmission speed. Motivated by the results in multiple-input multiple-output technologies, which are usually used at base sta-tions or access points, cooperation commutation has been proposed to improve the performance of wireless networks which consist of low-cost single antenna devices. While the majority of the research in cooperative communication focuses on flat fading for its simplicity and easy analysis, in practice the underlying channels in broadband wireless communication systems such as cellular systems (UMTS/LTE) are more likely to exhibit frequency selective fading. In this dissertation, we con-sider a frequency selective fading channel model and explore distributed diversity techniques in broadband wireless relay networks, with consideration to practical issues such as channel estimation and complexity-performance tradeoffs. We first study a system model with one source, one destination and multi-ple decode-and-forward (DF) relays which share a single channel orthogonal to the source. We derive the diversity-multiplexing tradeoff (DMT) for several re-