Cross-Layer Interaction Between TCP and UMTS RRM Scheduling Strategies

In the third generation wireless system UMTS, radio resource management (RRM) functions should encompass scheduling algorithms. In particular, scheduling mechanisms play a key role in resource allocation for UMTS shared channels. These shared channels are mostly used in UMTS to support services such as web browsing and e-mail that work with the transport protocol TCP. So, performance achieved by TCP users in shared channels is closely related to RRM scheduling. In this letter, we study the cross-layer interaction between TCP and two main sets of RRM scheduling strategies: rate-oriented and delay- oriented. Both strategies can be considered as the basic pillars behind more complex scheduling algorithms. We found that the low delay jitter achieved by rate-oriented scheduling is the reason for having a better TCP throughput in comparison with the delay-oriented scheduling algorithm. Results have been obtained with the aid of a real-time UMTS emulator.