Admission control strategies for dual transfer mode service in EGPRS networks

Dual transfer mode (DTM) has been defined by 3GPP for EGPRS networks. It provides simultaneous usage of GSM and GPRS services without requiring a full fledged GPRS class A terminal. DTM relies on the usage of half rate coders that makes it possible to share a time-slot between a voice call and a data session. The data session can he extended to more time-slots if necessary. This work intends to demonstrate that the optimal control policy adapted for the resource allocation in a cell providing DTM service is a threshold strategy. After a short introduction of the DTM capability, a traffic model for a cell providing the DTM service is introduced. Then, a reward function is defined to determine the structure of the optimal control policy. The numerical computations realized in the full paper show that the optimal policy is a threshold policy. The optimal policy is the policy that maximizes the reward function.