Abstract
Various next generation cellular systems are under development or deployment in order to meet rapidly increasing demand for high-speed wireless communications all over the world. Among them, EGPRS is a TDMA system evolved from GSM. By adopting EDGE air interface and supporting packet mode radio, EGPRS system can supply high data rate and improve system capacity significantly without requiring additional spectrum.NTHU and AT&T Labs have jointly developed an EGPRS test bed since last September for the purpose of investigating the performance of EGPRS system and studying QoS scheduling algorithms. This thesis is focused on implementation of a real-time emulated RLC layer for the EGPRS test bed. The design of the emulated RLC layer is based on a Radio Markov Model that was drawn from intensive offline system simulations for thousands of mobile users. Using the Radio Markov Model, time-varying wireless channels can be emulated in real-time by the RLC layer. A multi-queue based MAC layer scheduling algorithm is included in the RLC layer, which can assure QoS for real-time packet voice even if heavy burst data background traffic is presented. The RLC layer is programmed on Linux system as a virtual network interface device driver, which is independent of the Linux IP stack and thus making it easy for the EGPRS test bed to introduce IP-layer scheduling algorithms for QoS issues in EGPRS core networks.As a conclusion of this thesis, an experiment is conducted on the EGPRS test bed to demonstrate performance difference of real-time voice conversation between the case of multi-queue based MAC layer scheduling and that of single-queue routing. Some kernel parameters output from the RLC layer are presented in the thesis, which shows clearly that the multi-queue based MAC layer scheduling is necessary in order to assure QoS of real-time voice applications.