Analytical Bounds on the Area Spectral Efficiency of Uplink Heterogeneous Networks Over Generalized Fading Channels

Abstract

Heterogeneous networks (HetNets) are envisioned to enable next-generation cellular networks by providing higher spectral and energy efficiency. A HetNet is typically composed of multiple radio access technologies where several low-power low-cost operators or user-deployed small-cell base stations (SBSs) complement the macrocell network. In this paper, we consider a two-tier HetNet where the SBSs are arranged around the edge of the reference macrocell such that the resultant configuration is referred to as cell-on-edge (COE). Each mobile user in a small cell is considered capable of adapting its uplink transmit power according to a location-based slow power control mechanism. The COE configuration is observed to increase the uplink area spectral efficiency (ASE) and energy efficiency while reducing the cochannel interference power. A moment-generating-function (MGF)-based approach has been exploited to derive the analytical bounds on the uplink ASE of the COE configuration. The derived expressions are generalized for any composite fading distribution, and closed-form expressions are presented for the generalized- ${\cal K}$ fading channels. Simulation results are included to support the analysis and to show the efficacy of the COE configuration. A comparative performance analysis is also provided to demonstrate the improvements in the performance of cell-edge users of the COE configuration compared with that of macro-only networks (MoNets) and other unplanned deployment strategies.