We propose a new method of power control for interference limited wireless networks with Rayleigh fading of both the desired and interference signals. Our method explictly takes into account the statistical variation of both the received signal and interference power, and optimally allocates power subject to constraints on the probability of fading induced outage for each transmitter/receiver pair. We establish several results for this type of problem.

Power control is an essential radio resource management method in CDMA cellular commu-nication systems, where co-channel interference is the primary capacity-limiting factor. Power control aims to control the transmission power levels in such a way that acceptable quality of service for the users is guaranteed with lowest possible transmission powers. All users benefit from the minimized interference and the preserved signal qualities. In this thesis new closed loop power control algorithms for CDMA cellular communication systems are proposed. To cope with the random changes of the radio channel and interference, adaptive algorithms are considered that utilize ideas from self-tuning control systems. The inher-ent loop delay associated with closed loop power control can be included in the design process, and thus alleviated with the proposed methods. Another problem in closed-loop power control is that extensive control signaling consumes radio resources, and thus the control feedback band-width must be limited. A new approach to enhance the performance of closed-loop power control in limited-feedback-case is presented, and power control algorithms based on the new approach are proposed.

In this paper we investigate adaptive closed-loop power control algorithms based on the Generalized Predictive Control (GPC) method that are able to alleviate the effect of the loop delay inherent in the closed-loop power control of DS-CDMA systems, even if the loop delay is unknown. The numerical results indicate that the GPCbased algorithms can significantly improve the radio network capacity without any increase in power control signaling, even with unknown loop delay. 1.

The link level performance and the cellular system capacity in the uplink direction of a CDMA cellular system utilising multiuser detection base station receivers is analysed by simulation. In the receiver, parallel multistage multiuser detection is employed together with two-antenna diversity reception and fast closed-loop power control. A system level simulator is built to utilise the link level simulation results and to show the increase in cellular capacity obtained by using multiuser detection. The capacity is studied in urban micro and macro-cell environments utilising the channel models developed in the European CODIT project. The modelling of the environment specific and CDMA specific features is considered in the system simulator. The system level simulator is calibrated with analytical capacity calculations. 1.