A new channel assignment scheme for handoff and initial access in a microcellular CDMA system

In a personal communication services (PCS) network, a large number of users are densely populated in a cell area. However, the number of channels in a base station is limited. A handoff call to a new base station may be dropped or forcedly terminated. We propose a new channel assignment scheme for handoff and initial access which is suitable for a microcellular CDMA system. The proposed scheme is based on two principles. One is that a handoff call in non-line of sight (NLOS) communication with a new base station has priority over a handoff call in line of sight (LOS) communication; and the other is that an NLOS handoff call can preempt the channel of an LOS handoff call under a soft handoff procedure. We compare the proposed scheme with four other schemes: the non-prioritized scheme (NPS). The reserved channel scheme (RCS), the first-in/first-out (FIFO) queueing scheme, and the measurement-based prioritization scheme (MBPS). The simulation results indicate that the proposed scheme provides more reduction in the forced termination probability than the last two schemes as the offered traffic load or the percentage of handoff calls to total calls increases.