Delay and synchronization control middleware to support real-timemultimedia services over wireless PCS networks

摘要

This paper presents a discussion of several middleware designnissues related to the support of real-time multimedia communicationsnover wireless personal communication services (PCS) networks. Specificninterests are given to error recovery and synchronization mechanisms. Anhybrid automatic repeat request (ARQ) scheme is employed for errorncontrol in the proposed system because it can efficiently adapt tonnonstationary wireless channels and yield high throughput andnreliability. In particular, delay and delay jitter control related tonretransmissions in the error control module are addressed. An adaptivensource rate control mechanism is used to handle the fluctuation of theneffective channel data rate due to retransmissions. An adaptivensynchronization scheme is developed to compensate for long-term delaynvariation caused by large-scale fading so that synchronization isnpreserved and end-to-end delay is kept low. Simulation results from thenperformance evaluation of the system are presented