Interworking of satellite and terrestrial networks for land mobile communications

Land mobile satellite systems (LMSS) overcome the geographical limitation of terrestrial networks but the mobile satellite terminal (MT) suffers severe multipath fading and heavy signal shadowing when it operates inside an urban area. The authors describe an interworking approach that enables the MT to access the satellite system inside the coverage of the terrestrial network. The choice of communication link (either through satellite or terrestrial network) will depends on the quality, such as the carrier-to-interference ratio (C/I) or the bit error probability (BEP) of the received signals at the MT. Mathematical models to simulate the received signals at the MT and analyses on the characteristics of the simulated signals are presented. The registration procedures, channel structures, technical and economic issues related to the interworking scheme are also addressed