Soft handoff is one of major advantages in CDMA cellular systems guaranteeing seamless handoffs. However, few analytical studies on soft handoff have been attempted because of its complex phenomena. In this paper, a general mathematical approach for CDMA soft handoff modeling is introduced and the soft handoff is characterized in terms of the channel holding time in the soft handoff region, the channel holding time in the overlap region, and cell channel holding time. Their distributions and mean values are examined according to various parameter values. As either cell becomes larger or soft handoff region grows, the channel holding time becomes longer as expected. The result of this study can be utilized in the cell planning of CDMA cellular systems.
