Effects of Dominant Other-Sector Interference on Multi-Antenna HSDPA Performance

This paper provides link level SINR simulation results and network level sector throughput simulation results that quantify the benefit of dual antenna MMSE reception in a macrocellular HSDPA system. The dual antenna RAKE receiver serves as baseline reference. It is shown that the MMSE receiver's spatial interference suppression benefit heavily depends on the amount of experienced dominant other-sector interference. For example, in a Pedestrian A fading environment with a dominant other-sector interference ratio (DIR) of 6.5 dB, spatial interference suppression leads to approximately 3.5 dB mean SINR gain. For a much lower DIR of -1.5 dB the mean SINR gain shrinks to 0.8 dB. The simulation results are accompanied by a novel analytical bound that in flat Rayleigh fading and for uncorrelated rx antenna branches describes spatial interference suppression SINR gain as a function of DIR. The sector throughput benefit from spatial interference suppression remains below 20%. This relatively small benefit is due to the fact that high DIR situations > 2 dB are rare in the investigated macrocellular scenario. Moreover, the highest spatial interference suppression SINR gains occur in the upper part of the HSDPA system's dynamic range, where they map less efficiently into sector throughput.