File based mobile satellite broadcast systems: error rate computation and QoS based design

Mobile satellite broadcast systems have the potential of delivering entertainment, information and other data services with outstanding coverage and reliability. However, the long signal interruptions due to obstacles in the terminal environment that characterizes the land mobile satellite channel make the design of efficient air interfaces challenging. In this paper, a file based mobile satellite broadcast system is studied where, to overcome the signal blockages, packet time diversity is applied. Based on some simple assumptions, an analytical expression for the file error rate of the system is derived. Using this result, a design scheme is proposed that, for a given channel and file, minimizes the total number of transmitted symbols required to satisfy quality of service (QoS) constraints in terms of acceptable delay and file receive probability. The results can also be used to estimate the reduction in bandwidth requirements that can be achieved if users in demanding environments can be served using terrestrial repeaters or other means.