Performance study for a macrocell/microcell CDMA system with multi-channel selection

A CDMA cellular system can provide more capacity than AMPS systems and a hierarchical layer of cells is required for system design. However, system performance and capacity is degraded due to cochannel interference between microcells and macrocells if a single frequency channel is shared. This paper proposes four multi-channel access schemes where various frequency channels are assigned for microcells and macrocells. Performances of channel capacity, blocking probability and blocking ratio in uplink and downlink are evaluated. It shows that the schemes with all channels shared by macrocells and microcells gain more capacity than the scheme with channels partitioned absolutely in different cell tiers. Also channel segregation can reduce co-channel interference and improve system capacity especially by sequential reselection.