Paging signalling in non-GEO satellite mobile systems

As an important part of the mobility management function in satellite mobile systems, paging is used to notify the mobiles of incoming calls. To reduce the mobility signalling, two-step paging strategies are proposed. Two-step paging can increase the paging delay over the paging channel (PGCH) in case the first step paging fails. This delay could potentially degrade the service quality in terms of call set-up delay. Two scenarios of two-step paging strategy are proposed to counteract the channel fading effect, and therefore improve the quality of service in terms of the paging delay and PGCH capacity. The paging delay and the PGCH capacity are evaluated for different satellite constellations in a fading channel. The effect of the accuracy of predicted first step paging area (AFSP) and paging timer are also investigated, and the results are presented and discussed.