An Interference Mitigation Scheme using FFR and ABS for Device-to-Device Communications

Abstract

The Long Term Evolution (LTE) has been deployed for providing a universal platform for broadband mobile services at any time, any place and anywhere. Recently, due to rapid significantly and high data rate required. Due to the bandwidth shortage, 3GPP has introduced a new technique of Device-to-Device communication underlaying cellular network which can improve the spectral efficiency by enabling the direct communication of devices in proximity without passing through eNB. However, to enable D2D communication in a cellular network presents a challenge in radio resource management since D2D link reuses the uplink radio resources of the cellular user, this can cause the interference to the DUE receiver even though it can increase the network performance. In this thesis, we proposed a hybrid mechanism of using Fractional Frequency Reuse (FFR) and Almost Blank Sub-frame (ABS) to handle inter-cell interference caused by Cellular User (CUE) to D2D receiver (DUE_Rx) reusing the same resource at the cell edge area. In our case, we considered the DUE_Rx as victim nodes and CUEs as aggressor nodes. As our main target is to minimize the inter-cell interference in order to increase the SINR of the target DUE_Rx at the cell edge area. In the proposed hybrid FFR-ABS scheme, during ABS time the aggressor nodes will mute certain sub-frames in order to avoid the interference to the victim nodes. In order to achieve the proportional fairness for both CUEs and D2D pairs in the proposed scheme, we evaluate the number of optimal amount of ABS pattern. This ABS pattern can be muted on the aggressor node in order to guarantee the Quality of service (QoS) for both CUE and D2D pairs. The numerical results show that, the performance of the target D2D receiver (DUE_Rx) is increased significantly up to 80% compare to the conventional FFR only at the cell edge area.