Adaptive Frame Switching for UMTS UL-EDCH - Ping-Pong Avoidance

In this paper, we evaluated adaptive frame length switching algorithms for the enhanced uplink dedicated channel in UMTS. Different alternatives to achieve the frame switching are presented and discussed accompanied by results from simulated system throughput performance. Moreover, we also discussed the implementation issue associated with avoiding ping-pong effect caused by mobile movement. Dynamic system simulation was performed and it showed 10% improvement by switching between 2 ms and 10 ms TTI (frame) transport channels for EDCH with different threshold selection. The results show that the adaptive switching based on the user geometry with ping-pong avoidance has the most performance gain over fixed TTI system