Interference analysis of subband allocation for femtocells in fractional frequency reuse based OFDMA Networks

In Fractional frequency reuse (FFR) based cellular networks which employ femtocells to fulfill the higher data rate requirements, the throughput performance of femtocells are primarily limited by the co-channel interference due to the frequency reuse. However, in orthogonal frequency division multiple access (OFDMA) systems, allocation of an optimum frequency subband based on the minimum interference present in all the available subbands, can improve the performance of femtocells considerably. This paper presents an energy based analysis related to the subband allocation considering the asynchronization effects of interfering signals occurring due to the propagation delays and timing offsets in the network. Based on the analysis presented here, a femtocell can be configured to provide improved performance by selecting a subband least affected by the interference.