User mobility support in an urban CDMA-based wireless network

Abstract

A salient feature of wireless networks is the ability to support user roaming. However, user mobility has a profound effect on grade of service (GoS) and quality of service (QoS) provisioning. Code division multiple access (CDMA) is the multiple access technology for the third-generation wireless standard (3G) and is envisioned to be the multiple access technology beyond 3G. CDMA is interference-limited. The signal-to-interference (SIR) ratio, expressible in the form of Eb/I0, is an important parameter in CDMA systems and has a profound effect on the system capacity. The system capacity in turn affects the call-level GoS of the network layer in terms of new call blocking probability and forced termination probability. The effect of user mobility on (i) degradation in utilization and (ii) excess capacity needed to satisfy the QoS/GoS requirements, in an urban environment, is examined and quantified. A relationship between the link-layer Eb/I0 specification and the call-level GoS parameters in the presence of user mobility is also established. Numerical results which display the linkages between the link-layer QoS and call-level GoS parameters are presented and discussed. This coupling gives a quantification of the link-layer requirement to provision the call-level GoS, in the presence of user mobility.