The Effects of Varying Soft Handoff Thresholds in Cellular CDMA System
Bongkarn Homnan, Watit Benjapolakul, Katsutoshi Tsukamoto, Shozo Komaki · OUKA (Osaka University Knowledge Archive) (Osaka University) · 2004
In order to benefit from the advantages of soft handoff (SHO), it is important that the SHO parameters (the SHO thresholds; T ADD and T DROP are well assigned.T ADD is the threshold used for triggering a pilot with high strength to be added to the Active Set (AS) list.The AS means the pilots associated with the forward traffic channels assigned to mobile station.In contrast, T DROP is the threshold used for triggering a pilot with low strength to be dropped from the AS list.This paper analyzes the effects of varying SHO thresholds in a cellular code division multiple access (CDMA) system on the blocking probability based on traffic load and geometrical distances in hexagonal layout of base stations (BSs).In addition, the previously proposed traffic load equation [1] is applied to the proposed SHO model for balancing the numbers of new and handoff calls on the forward link capacity in case of uniform traffic load.The results show that the blocking probability is more sensitive to T DROP than to T ADD variations.