This paper proposes a Multi-hop Radio Access Cellular (MRAC) scheme for achieving both highspeedihigh-capacity and good area coverage in fourth generation mobile communications systems. In this scheme, we assume two kinds of hop stations, one is a dedicated repeater station installed at a good propagation location such as a rooftop, and the other is a user terminal that temporarily experiences good propagation conditions. For both cases, the path diversity effect can be obtained between single-hop and multi-hop paths. Four propagation models were studied representing the paths among the base station, hop stations, and mobile station. Based on the propagation models, suitable MRAC operation conditions are discussed. For mobile stations located at the cell edge area, MRAC operation is effective in reducing the transmit power. Consequently, MRAC reduces the interference in cellular systems and enhances the area coverage.

No abstract

SUMMARYThe use of multihop connection, in which a station in between the mobile station and the base station performs hopping relay of the transmission, in CDMA cellular systems should expand the area coverage and reduce the transmitted power per hop. There is a possibility that interference power may be reduced and that system capacity may be enlarged by this approach. Depending on the method of application, however, the system capacity may be decreased due to the interference during hopping. In this study, a basic investigation of interference reduction by multihop connection is first presented. Then, a procedure for selection of the hop stations with a strong capability for reducing the interference power is proposed. Considering a multicellular environment with a CDMA (code division multiple access) cellular scheme, the characteristics of multihop connections are evaluated by computer simulation, assuming packet access. It is shown that multihop connection has the effect of improving system capacity.

No abstract

No abstract