A Power Assignment Scheme for Improving Outage Probability in HSDPA

Bit or frame error rates are commonly used as performance measures in wireless communication systems. However, in emerging applications such as voice over IP (VoIP), the bit rate outage probability is often a more useful performance measure. In this paper, an accurate method is proposed for approximating the probability distribution of the downlink received signal-to-interference ratio (SIR) in the high speed downlink packet access (HSDPA) channel of a 3GPP network. Based on this distribution, a power adjustment scheme is proposed to minimize the weighted sum of bit rate outage probabilities for multiple users. It is shown that the proposed method can greatly improve outage probability fairness without incurring a very large degradation in throughput.