The performance of voice over IP over 3G downlink shared packet channels under different delay budgets

One important issue in 3G wireless systems is to port voice service to the new packet-data-based platform while retaining the quality of service (QoS) that users associate with present-day circuit-switched realizations. Flexibility in packet switching introduces difficulty in maintaining QoS requirements, in particular, the delay requirement. In this work, we conduct research on delay performance of Voice over Internet Protocol (VoIP) services over high speed downlink packet access that is used in 3G systems to provide high speed packet data service. We evaluate the VoIP network capacity under different packet delay budgets that associated with the radio access channel. We also investigate the impact of rate profile, spreading factor, code capacity, multiplexing capacity and header compression algorithm.