PN offset planning in IS-95 based CDMA systems

PN offset planning in IS-95 based CDMA systems is systematically addressed in this paper. The minimum reuse distance for the same pilot PN offset is derived based on pilot signal strengths. The reuse distance is a function of receiver sensitivity, propagation path loss, system configuration, search window size and hand-off parameters. It is found that the required reuse distance decreases from six times of cell radius to one cell radius, when the path loss slope increases from 20 to 50 dB/decade. The minimum pilot offset interval between two adjacent base stations is a function of propagation delay spread, hand-off parameter settings and cell distance difference. The minimum pilot separation between two adjacent cell sites will increase when the hand-off area increases. Several PN offset aliasing cases in the CDMA system deployment are discussed. Pilot PN planning strategy is also addressed. System deployment demonstrates that the established criteria are sufficient to avoid the pilot PN offset ambiguity