An Interference Mitigation Scheme for Millimetre Wave Heterogeneous Cloud Radio Access Network with Dynamic RRH Clustering

Abstract

In its early deployment, 5G is expected to be integrated with conventional micro wave (µw) base stations (BSs) in small cells using millimetre wave (mmw) band for access to enhance the traditional system. The main goal of 5G is universal coverage and at a higher rate. In this paper, a scheme for increasing the rate coverage of the conventional macro cell by exploiting the wide mmw band spectrum is proposed. This scheme is inspired by the Soft Frequency Reuse (SFR) technique. Since the cell edge area has a lower coverage rate due to high interference and less received power, it is served by a mmw band. Small mmw Remote Radio Heads (RRHs) are overlaid onto conventional macro cell on cells edges in a Heterogeneous Cloud Radio Access Network (HC-RAN) architecture. The neighbouring RRHs are clustered together based on the suggested clustering algorithm. The RRH clustering problem formulated as a bin packing problem Simulation results show that the HC-RAN system adopting the suggested scheme has significantly higher coverage and rate compared to an HC-RAN system with small cells only deployed in hot spots. Specifically, a gain of 20%-40% is achieved in coverage and rate when compared to the systems applying the SFR technique and HC-RAN architecture with randomly deployed mmw RRHs. This enhancement in rate and coverage is due to a significant reduction in the interference level resulting from the adopting the suggested scheme, which benefits from high path loss, blockage and wide band properties of an mmw channel. Furthermore, the impact of the mmw cell size and density on the system performance is investigated.