Throughput and Delay Performance of Mobile Internet Applications Using LEO Satellite Access

Low Earth Orbit (LEO) satellites are an essential complement of the cellular radio infrastructure, especially the Universal Mobile Telecommunications System (UMTS), for mobile (pedestrian and, more important, vehicular) access to the Internet in sparsely populated areas, where high bandwidth UMTS cells cannot be economically deployed. LEO users would eventually switch between the satellite segment and the terrestrial one depending on the environment in which they are located. In this paper we analyze various mobile Internet applications in representative urban scenarios for two existing LEO systems. To this end, we develop a LEO channel propagation model that includes shadowing from surrounding building skylines, based on actual data in a built-up area. We consider “single satellite hop” transmissions from the mobile terminal to the satellite gateway. For this scenario, we compute via simulation the performance for FTP and HTTP applications as perceived by mobile users traveling at varying speeds along “urban canyons”. We then consider a multi-hop satellite path between remote urban locations and evaluate the performance of delay sensitive applications. We also evaluate the performance of various TCP versions (Tahoe, Reno, SACK) in different presence of packet loss.