Multihop Mobile Communications System Adopting Fixed Relay Stations and its Time Slot Allocation Schemes

In this paper, we present a multihop mobile communications system utilizing fixed relay stations to enhance the coverage of the service area. A multihop mobile communications system was originally proposed as a system in which only mobile stations relay communication between other mobile stations and a base station to solve the problem of poor coverage expected in a future cellular system. In the system, however, a probability of a mobile station being able to connect with a base station via their relay functions is governed by a probability of mobile stations existing in its neighborhood. Therefore, we introduce fixed stations as relay stations in addition to relay functions of mobile stations to enhance the probability of link conductivity between a base station and a mobile station. By adopting this multihop architecture, a mobile station which needs relay functions can choose relay stations among fixed relay stations or other mobile stations. Moreover, we also examine its time slot allocation methods. We confirmed that the ratio of successful connection between mobile stations and base stations improved about 0.15 by introducing just 4 fixed relay stations in a certain environment