We present simulation results, which are based on detailed modelling of the talk-spurt nature of conversations, and the full GPRS protocol stack. Our results show that the use of appropriate reservation methods and the use of VoIP offers clear benefit in terms of the user numbers that can be supported. Under conservative estimates, a single GSM RF carrier can support over 15 simultaneous conversations. This is a considerable improvement over GSM using full rate traffic channels (TCH/F) and is also better that half rate traffic channels (TCH/H) unless the penetration of TCH/H mobile stations (MSs) is very high. The paper considers a number of resource request strategies, which are described and then compared. The construction of the GPRS simulation environment is also described.