Analytical Evaluation of Throughput and Coverage for FFR in OFDMA Cellular Network

Abstract

Fractional frequency reuse (FFR) is an efficient management technique to eliminate inter-cell interference (ICI) in multi-cell orthogonal frequency division multiple access (OFDMA) networks through inter-cell coordination. Generally, the derivations of throughput and coverage probability are treated as separate problems or investigated in different ways. In this paper, we derive average cell throughput and coverage probability expression for both round robin (RR) and maximum SINR (MSINR) scheduling strategies with different subcarrier allocation schemes from the same starting-point, the cumulative distribution function (CDF) of the instantaneous SINR . Results of static and dynamic subcarrier allocation schemes are compared to verify that latter is more reasonable because it takes both throughput and fairness into consideration. Analytical and simulation results also show that average cell throughput increases and coverage probability decreases with the distance threshold. Based on this, we investigate the optimal distance threshold to attain as good balances between throughput and coverage with different number of users in a cell. In terms of base station (BS) power control, we demonstrate that there exists an optimal power to satisfy coverage probability and obtain maximum throughput no matter what scheduling strategy is applied.