Performance Analysis and Comparison of Relay-Aided Cellular Networks under Various Propagation Conditions

The Co-Channel Interference (CCI) is a crucial problem in cellular networks. Therefore, this paper addresses the CCI in Relay-Aided (R-A) cellular systems. Two different interference mitigation models are studied. The first model denotes the R-A strict Fractional Frequency Reuse (FFR) with Frequency Reuse Factor (FRF) equal three. Moreover, the second model represents R-A strict FFR with FRF equal four. For further network performance improvement, two configurations for each model are considered. The first configuration assumes six Relay Stations (RSs) per cell while the other one proposes three RSs in each cell. The best RSs locations in terms of SIR are proposed. Analytical treatments are conducted considering the worst cases of Cell Edge User's (CEU's) and Cell Center User's (CCU's) Signal to Interference Ratio (SIR). These treatments resulted in closed form expressions for worst cases CEU's, CCU's SIR and inner radius. These expressions are used to compare different models and configurations. The work results enable the system designer to characterize and optimize the multi-cell network performance without the need to execute complex calculations. Also the obtained results contributes to achieve much higher network performance improvement with a lower network cost.