Adaptive power control for multi-antenna and cooperative communications with imperfect channel knowledge

Abstract

In this thesis, we consider adaptive power control for multi-antenna and cooperative fading channels with imperfect channel state information (CSI). The thesis comprises two main parts. In the first part, we study temporal power control in multi-antenna and cooperative relaying channels subject to long-term power constraints at the transmitters, with a focus on the asymptotically high signal-to-noise ratios (SNRs). Efficient power control schemes based on noisy CSI at the transmitters (CSIT) and/or receivers (CSIR) are proposed to maximize the achievable diversity-multiplexing tradeoff (DMT). We also provide a framework to systematically study the achievable DMT in multi-input multi-output (MIMO) and cooperative systems with noisy CSI. We firstly consider a MIMO system and develop novel two way training strategies to improve the DMT. To make more efficient use of the imperfect CSI, joint power and rate control schemes are proposed which drastically increase the achievable DMT, especially at high multiplexing gains. Next, we extend the DMT analysis to cooperative relaying channels. Both conventional amplify-andforward (AF)/decode-and-forward (DF) and dynamic DF (DDF) relaying protocols are considered. We show that long-term power control based on imperfect CSIT significantly improves the DMT of the conventional AF and DF relaying protocols. Moreover, it is shown that the DDF relaying, which supports higher spectral efficiencies, also enjoys a further improved DMT over the conventional relaying protocols. In the second part, we study spatial power control in cooperative relaying channels to minimize the system outage/error probability. In particular, we coniii ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library