Full-Rate Speech Quality on Half-Rate Channels - Performance Comparison of GMSK and 8-PSK Modulated AMR-NB Codec Modes in GERAN Mobile Radio Networks

Abstract:
Growing traffic load in today’s wireless networks brings up new challenges with respect to capacity. Simultaneously the demands for high quality voice services are rising. AMR half-rate in 8-PSK modulation combines both aspects and provides doubling the GERAN capacity just at a slight degradation of the perceived speech quality. A detailed performance study of 8-PSK modulated AMR half-rate codec modes is presented based on network planning studies and profound system level simulations. In addition a performance comparison to GMSK modulated AMR half-rate and full-rate codec modes has been provided. This analysis is focused on speech quality, coverage and capacity by AMR-NB in GERAN networks applying different frequency re-use patterns ranging from relaxed 4x3 to tight 1x1. The trade-off between quality and capacity has been demonstrated as well as the gain provided by 8-PSK modulated AMR half-rate. Network configurations offering full-rate quality by the allocation of half-rate channels have been identified. The capacity gain can be used to serve additional subscribers and/or to increase the quality and capacity of GPRS/EDGE data services.