Stochastic Geometry Analysis of Downlink Spectral and Energy Efficiency in Ultradense Heterogeneous Cellular Networks

Jiaqi Lei,Hongbin Chen,Feng Zhao

doi:10.1155/2018/1684128

Jiaqi Lei, Hongbin Chen + Show 1 more

Open Access

https://doi.org/10.1155/2018/1684128

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Abstract

The energy efficiency (EE) is a key metric of ultradense heterogeneous cellular networks (HCNs). Earlier works on the EE analysis of ultradense HCNs by using the stochastic geometry tool only focused on the impact of the base station density ratio and ignored the function of different tiers. In this paper, a two-tier ultradense HCN with small-cell base stations (SBSs) and user equipments (UEs) densely deployed in a traditional macrocell network is considered. Firstly, the performance of the ultradense HCN in terms of the association probability, average link spectral efficiency (SE), average downlink throughput, and average EE is theoretically analyzed by using the stochastic geometry tool. Then, the problem of maximizing the average EE while meeting minimum requirements of the average link SE and average downlink throughput experienced by UEs in macrocell and small-cell tiers is formulated. As it is difficult to obtain the explicit expression of average EE, impacts of the SBS density ratio and signal-to-interference-plus-noise ratio (SINR) threshold on the network performance are investigated through numerical simulations. Simulation results validate the accuracy of theoretical results and demonstrate that the maximum value of average EE can be achieved by optimizing the SBS density ratio and the SINR threshold.

Highlights

With the rapid growth of smart terminals, the wireless data traffic presented an exponential growth in recent years, which demands a much higher link throughput
We focus on the optimization of network parameters (SBS density ratio and signal-tointerference-plus-noise ratio (SINR) threshold) to maximize the average EE without considering these related technologies
(3) To evaluate the average downlink throughput experienced by user equipments (UEs) in the small-cell tier, instead of using the average ergodic rate, the SINR threshold is taken into account, and impacts of the small-cell base stations (SBSs) density ratio and SINR threshold on the average EE are investigated. e aim is to provide a tractable approach to seek the optimum SBS density ratio and SINR threshold to maximize the average EE while meeting minimum requirements of the average link spectral efficiency (SE) and average downlink throughput experienced by UEs in macrocell and small-cell tiers, which is meaningful to guide the actual deployment of ultradense heterogeneous cellular networks (HCNs)

Summary

Introduction

With the rapid growth of smart terminals, the wireless data traffic presented an exponential growth in recent years, which demands a much higher link throughput. The optimization problem of maximizing the average EE while meeting the average link SE and average downlink throughput requirements in the two-tier ultradense HCN is considered, and impacts of the SBS density ratio and SINR threshold on the network performance are investigated. E aim is to provide a tractable approach to seek the optimum SBS density ratio and SINR threshold to maximize the average EE while meeting minimum requirements of the average link SE and average downlink throughput experienced by UEs in macrocell and small-cell tiers, which is meaningful to guide the actual deployment of ultradense HCNs. e rest of this paper is organized as follows: in Section 2, the two-tier ultradense HCN model, channel model, power consumption model, and association scheme are described. UEs served by an MBS in the macrocell tier, Ns represents the number of UEs served by an SBS in the small-cell tier, the subscript x represents the distance between the reference UE and its nearest SBS (denoted by k0), and subscripts m and s represent the MBS and SBS, respectively

System Models

Network Performance Analysis

Simulation Results

Conclusions