Chapter 8 - Handover in IS-95, cdma2000, 1X-EV, and WCDMA

Abstract

The chapter introduces the concept of handover in IS-95–based code division multiple access (CDMA) systems and wideband CDMA (WCDMA). It discusses the three types of handovers in cellular systems: intra-frequency, inter-frequency, and inter-system. The concept of CDMA intra-frequency handovers entails the use of pilot sets. These are base station pilots (referenced by their PN offsets for IS-95–based systems or by their scrambling codes for WCDMA) that are grouped according to their functionality in the handover process. The IS-95 system manages handovers through the use of the different pilot sets. These pilot sets are updated by the network through a handoff direction message (HDM), a Layer 3 message sent by the base station to the mobile station. The mobile confirms successful reception of the HDM through the handoff completion message (HCM). The necessary procedures behind pilot set maintenance are also discussed. The extensions of these concepts to WCDMA, cdma2000, and 1X-EV systems have also been explored. Moreover, the concept of cell site selection in 1X-EV systems is described, along with its effects on set maintenance.