| Wireless communication network is an important area of modern technology. To ensure reliable communications in an inevitably uncertain and ever-changing environment, link adaptation is necessary. In addition, since wireless devices typically have limited power supply and mobile users often want to communicate regardless of their locations, power-efficient and location-fair link adaptation is highly desirable.; This dissertation is devoted to the analysis and design of power-efficient and location-fair link adaptation protocols for wireless networks. It addresses fundamental issues in data rate control and power management, develops practical adaptation protocols, and analyzes their performance.; More specifically, in data rate control, the maximum achievable average throughput of feedforward controllers is derived. The optimal controller is found to be channel-independent but non-causal. A suboptimal implementable controller, which yields significant increase in average throughput over fixed data rate operation in Rician fading channels, is designed and shown to outperform existing protocols.; In power management, both TDMA and CDMA systems are considered. For TDMA systems, the optimal transmission policy, which maximizes power-efficiency, is proved to be of threshold nature. This policy is simplified, resulting in a suboptimal threshold policy that is 11 dB more power-efficient than traditional TDMA. It is however location-unfair and, thus, is suitable only for delay-insensitive applications. To overcome this limitation, we develop a location-fair adaptive threshold policy that offers 3.6 dB power-efficiency improvement over traditional TDMA.; For CDMA systems, an N-choose-n operation, where n out of N users are chosen to transmit at a time, is introduced. The set of feasible pairs (N, n), which ensures every user a desired average throughput, is characterized. The optimal N-choose-n operation is proved to be ranking-based, i.e., selecting the n users with the largest channel gains maximizes power-efficiency. The resulting system, referred to as Ranking CDMA, is 14 dB more power-efficient than traditional CDMA, but lacks location-fairness. This deficiency is alleviated by a location-fair Adaptive Ranking CDMA that is still 5 dB more power-efficient than traditional CDMA. |
