A novel BER-feedback power control algorithm for Personal Area Network Devices

Personal Area Network (PAN) Devices are often components of communication systems which opportunistically access the wireless spectrum. As such, they must operate without presenting interference to licensed users, while meeting their individual, varied Quality of Service (QoS) requirements. In this paper we use a novel Transmit Power Control (TPC) algorithm to reduce interference. In theory, over the life of a Secondary User´s (SU´s) transmission, there is an optimal power time curve reflective of the minimum amount of power necessary with which a device can transmit while maintaining acceptable BER, and practicing Interference Avoidance (IA). Using the response of the algorithm to instantaneous channel conditions as well as an iteratively updated QoS benchmark, we obtain a quadratic approximation of the desired power-time curve. Stability of the quadratic approximation is demonstrated through Matlab simulations using critical valued inputs to the approximator. From our results, we also show that our quadratic approximator outperforms others of different orders in terms of reduction in sensitivities to relatively small changes in inputs, and better tracking performance in following reference desired power curves used in the simulations. Our algorithm reduces transmit power (and thus interference) by approximately 3.5 dB compared to conventional methods while maintaining the required QoS.