Fairness guaranteed novel eICIC technology for capacity enhancement in multi-tier heterogeneous cellular networks

Qixun Zhang,Tuo Yang,Zhiyong Feng,Yue Zhang

doi:10.1186/s13638-015-0300-y

Abstract

Driven by surging demands for high data rate services and better user experiences, there is an increasing capacity demand in heterogeneous cellular networks. As one of the promising solutions for capacity enhancement, densely deployed small cells are proposed to provide a huge capacity gain and improve the user experience with high data rate services. However, the inter-cell interference among densely deployed cells is a big challenge that constraints the performance of capacity improvements in hierarchical multi-tier heterogeneous cellular networks. To minimize the inter-cell interference and achieve a fairness guaranteed solution among different users, a novel enhanced inter-cell interference coordination (eICIC) technology is proposed by jointly considering about the cell range expansion (CRE) scheme to minimize interferences among multi-tier cellular networks, improving the network throughput and quality of service (QoS). Optimal CRE bias and almost blank subframe (ABS) ratio solutions are achieved in this paper by considering the fairness among users at the center and cell edge. Moreover, the multi-objective decision-making problem is solved by maximizing the proportional fairness (PF) utility and area capacity in multi-tier heterogeneous cellular networks. Simulation results denote that a tradeoff between fairness and network throughput is achieved when CRE bias is from 8 to 12 dB and ABS ratio is from 4/8 to 6/8.

Highlights

The rapid developments on various applications and different service demands in cellular networks lead to the exponentially surge on mobile traffics
By utilizing the enhanced inter-cell interference coordination (eICIC) technology, the signal to interference plus noise ratio (SINR) of Picocell UE using CRE (PUEcre) only suffer the interference from other picocells, which is depicted in the eICIC technology is an effective solution to reduce the interference from macrocell to PUEcre in multi-tier heterogeneous cellular networks
Considering different parameters that affect the performance of system capacity in multi-tier heterogeneous cellular networks, key parameters, such as the base stations (BSs) density, cell range expansion (CRE), and eICIC, are discussed with numerical results in terms of different ratios of picocell UE (PUE), system throughput of various cells

Summary

Introduction

The rapid developments on various applications and different service demands in cellular networks lead to the exponentially surge on mobile traffics. Considering the disadvantages of existing works and problems unsolved, a novel eICIC technology is proposed by jointly considering the CRE scheme to minimize interferences among multi-tier cellular networks in this paper, improving the network throughput and QoS and guarantee the fairness of users Both the poisson point process (PPP) model and two metrics of capacity performance are used including the average capacity per cell and the average capacity per area unit. Considering the cell association, different users will choose the appropriate serving BS in the kth tier with the strongest RSRP value as Pr,k = PkhZk−αk Bk, where Zk denotes the distance between UE and BS and h is the channel gain with a Rayleigh distribution, i.e., h ∼exp(1) Both the transmit power ratio of BS and the CRE bias ratio of interfering BS to serving BS are shown in Equation 1. Nk λu Ak λk as denoted in Equations to 8

Resource partitioning using eICIC technology

Capacity analysis using CRE and eICIC technologies

Optimal CRE bias and ABS ratio solution based on fairness

Results and analysis

LTE-A system-level simulation results of novel eICIC technology

Conclusion