Hybrid channel adaptive handover scheme for non-GEO satellite diversity based systems

This article presents an improved hybrid handover scheme, which is proposed for the satellite component of UMTS. The scheme is channel adaptive and is generic as it can operate in soft and hard handover. The handover algorithm uses different power thresholds to add/drop a highest and second highest satellite and uses dual satellite diversity only under critical channel conditions. The analysis includes the simulation of a LEO constellation and the elevation-dependent satellite channel. Based on the channel time series the hybrid scheme shows improved performance when compared to existing handover schemes and is less bandwidth demanding than continuous diversity.