This volume presents the proceedings of the Fourth Workshop on Multiaccess, Mobility and Teletraffic for Wireless Communications held in October 1998 in Washington, D.C. The focus of this workshop is to identify, present and discuss the theoretical and implementation issues critical to the design of wireless networks. To ensure proper network design and engineering, designers of wireless networks need to understand and address issues such as radio propagation, antenna, interference management, multiaccess, mobility, teletraffic, signalling and networking prools. In fact, not only do these issues need to be understood and addressed, their interdependence and interactions also deserve to be examined closely. Therefore, the goal of this workshop is to present papers addressing these issues, with the hope of stimulating further collaboration among researchers of various disciplines in wireless communications. High-speed wireless networks such as wireless ATM and GSM with high-speed data services continue to attract much research and development efforts. The major challenges on the physical and link layers in these networks include radio design, interference management, resource allocation and multiaccess prool. Several papers on these issues are presented here. As the availability of radio spectrum is limited, there is always a desire to ''maximize'' the spectral efficiency, for example, by diligent (and perhaps dynamic) re-use of frequency and cell layout, while guaranteeing a certain quality of service (QoS). A number of papers at this workshop address these topics.