Supporting integrated voice and data traffic over EGPRS
Xiaoxin Qiu, Chang Li, Kapil K. Chawla, J.C.-I. Chuang, N.R. Sollenberger, James Whitehead · 2002
We investigate the performance of voice and best-effort data traffic over Enhanced General Packet Radio Services (EGPRS) using tight reuse configurations (e.g. 1/3 or 1/1), with the aim of identifying suitable bearer designs and optimal system configurations for these services. We find that voice and data have somewhat conflicting preferences: voice capacity is optimized using random frequency hopping and quality-driven power control: data throughput is optimized using no frequency hopping and no power control. These somewhat contradictory requirements impose a challenge in the system design. We investigate two simple traffic integration strategies: (1) segregating the resource for the two services and using the optimal configuration in each segment; and (2) integrating the traffic by allowing voice and data to share the same resource, and use a compromised configuration for the entire system. We find that if the majority of traffic is voice, traffic integration has an advantage since data can use any residual voice capacity. On the other hand, if the majority of traffic is data, segregation provides higher spectrum efficiency. Furthermore, the integrated traffic option becomes increasingly sub-optimal with increasing data traffic load. We conclude that the system design should depend upon the expected mix of traffic (including traffic types in addition to voice and best-effort data) and the desired engineering complexity, and that further work is needed to understand the possible design options. One possible design option is to soft segregate the resource, e.g., to allow data to use the voice segment on an overflow basis. Similar strategies may be good avenues for future work.