Cross Time Slot Capacity Analysis for Uplink Transmission in Multihop Cellular System

Multihop cellular system seems to be a promising candidate for third generation and beyond 3G (B3G) system because of its wide coverage area and high access throughput. In this paper, we analyze the uplink system capacity of a TDD-CDMA multihop cellular system with a simple multihop access model. In this model, a cell area is divided into two regions: inner-region and outer-region. The mobile users in the inner- and outer- region of the cell communicate with base station and relay station, respectively. Based on this simple model, we first analyze the uplink system capacity in both regions with the assumption that the inter-cell and intra-cell interference follow the Gaussian distribution. In addition, in order to establish a fair comparison with conventional TDD-CDMA in terms of system throughput, we introduce a practical comparison equation. This is because multihop cellular system uses more than one radio resource for one communication link. Finally, we discuss the best placement of the relay station and the size of the inner-outer boundary, from which the highest system capacity is achieved. From the analysis and simulation results, we conclude that multihop cellular system can improve the TDD-CDMA system capacity significantly if a proper relaying access scheme is selected