SIR analysis for non-uniform HetNets with joint decoupled association and interference management

Abstract

In heterogeneous cellular networks (HetNets), fractional power control (FPC) is used in uplink (UL) transmission to improve signal-to-interference ratio (SIR) by compensating path loss. However, employing FPC results in a significant co-channel UL interference (UL-I) as a result of increased users’ transmit power. Moreover, macro base station (MBS) edge users make the situation exacerbate by transmitting with even higher power to compensate path loss and, thus, render FPC highly unsuitable in HetNets. In this paper, we aim to decrease severe UL-I and, thus, leverage FPC in HetNets. Hence, we propose non-uniform HetNets (NUHs) where small base stations (SBSs)’ deployment near MBS is avoided by using Poisson hole process (PHP). NUHs provide: (i) improved coverage due to coverage-oriented SBS distribution, and (ii) lower MBS-interference (MBS-I) as the SBSs are only deployed in coverage edge area of MBS. In conjunction with NUH, we employ decoupled association (DeCA), in contrast to coupled association (CA), to improve UL SIR. NUH along with DeCA provide lower UL-I and MBS-I due to reduced interference and improved UL SIR. Additionally, to efficiently utilize the radio resources, we employ reverse frequency allocation (RFA) to mitigate inter-cells-interference (ICI). We compare CA with DeCA in different network scenarios. Results indicate that the employment of DeCA leads to improved UL coverage, as compared with CA, due to effective mitigation of UL-I, MBS-I, and ICI. Moreover, the results indicate significant improvement in UL coverage for the SIR threshold values greater than 0 dB. Furthermore, the results show that a higher value of FPC compensation factor improves the coverage performance.