A semi-blind base station power estimation algorithm for interference aware HSDPA receivers

In order to mitigate multipath and inter-cell interference in a mobile terminal, the received signal statistics have to be estimated. In a Code Division Multiple Access (CDMA) system with multiple users, it is difficult to estimate all sources of interference directly. The multipath channel can be estimated using a pilot sequence, but since the pilot is code-multiplexed, it gives no indication for other code powers. We show that assuming a fixed ratio between pilot power and total power has a severe impact on throughput performance if multipath or inter-cell interference are dominant. We develop a low-complexity, semi-blind power estimation algorithm, which is optimized for minimum estimation variance and delay. The algorithm is benchmarked using the interference aware High Speed Downlink Packet Access (HSDPA) type 3i reference implementation as defined by the 3GPP standard.