Performance of VoIP on EUTRA downlink with limited channel feedback

Abstract

The emerging evolved UTRA radio system is generally envisioned to support a large number of VoIP users. This is basically enabled by efficient frequency domain packet scheduling together with accurate channel quality feedback information. In this paper, we investigate the performance of VoIP on EUTRA downlink assuming that only limited channel quality feedback information is available. System level simulation results show that by increasing the CQI measurement frequency window to 2 PRBs and using average best-4 CQI reporting scheme, the achieved VoIP capacities for no packet bundling case and packet bundling case are 201 users/sector and 353 users/sector respectively with 6 control channels. Compared with the ideal CQI measurement frequency window of 1 PRB and full CQI reporting scheme, the relative loss of VoIP capacity is negligible for no bundling case and about 9% for bundling case. On the other hand, the reported CQI wordsize in uplink can be significantly decreased by 84% from 126 bits to 20 bits.