A variety of conversational multimedia services have been developed and provided for a FMC (Fixed Mobile Convergence) environment, which contains a variety of wireless networks, such as 1x EV-DO (1x EVolution Data Only), WiMAX (Worldwide Interoperability for Microwave Access), WiFi (Wireless Fidelity) and combinations. The bandwidths of several wireless networks are asymmetric and restricted. For example, for the asymmetric link, 1x EV-DO specifies the peak rates for downlink and uplink as 2.4Mbit/s and 153Kbit/s. A header compression scheme for the transmitted packets of conversational multimedia signals is an effective solution for these scarce links, especially in the IPv6 environment. However, ways to improve the performance of the header compression scheme have not been thoroughly evaluated quantitatively considering the quality of conversational multimedia services over the asymmetric wireless links where the transmission characteristics of the up and down links are quite different.

This paper presents the results of a study that examined ways to improve the performance of the header compression scheme based on control of the header compression parameters considering speech quality over the asymmetric wireless link. The paper also presents experimental verifications of the efficiency of our proposal using a practical implementation.