Joint ABS and user grouping allocation for HetNet with picocell deployment in downlink

Wei-Chen Pao,Jhih-Wei Lin,Yung-Fang Chen,Chin-Liang Wang

doi:10.1186/s13638-017-0945-9

Abstract

In order to resolve the co-channel inter-cell interference problem in heterogeneous networks (HetNet), the feature of almost blank subframes (ABS) in the time domain of the enhanced inter-cell interference coordination (eICIC) is utilized. In this paper, an ABS configuration design is developed on downlink in HetNet and the associated resource allocation problem for maximizing the system performance with fairness among user equipments (UEs) is considered. Compared to conventional problems, the resource assignment problems include the configuration of ABS pattern and the resource allocation for macro UEs and pico UEs, which aims to maximize the downlink throughput and balance the traffic offloading in intra-frequency HetNet deployments. First, this paper introduces an ABS pattern design by using the channel condition, which is developed in terms of the time domain resource. Subframes are categorized as protected or normal subframes for reducing interference impact to pico UEs. Based on the configuration of the ABS pattern, we develop a grouping strategy to determine which pico UEs use either protected or normal subframes. Besides, the assignment of resource blocks with respect to the resource in the frequency domain is developed along with the fairness among UEs. The proposed joint allocation scheme takes the system throughput and the fairness into account, and has better performance than the existing schemes. Simulation results also reveal that the performance of the proposed joint allocation scheme approximates the optimal solution with the full search scheme.

Highlights

Orthogonal frequency division multiple access (OFDMA) system has been chosen for the next-generation broadband wireless system standards [1] in order to satisfy the growing demands on the high data traffic in the mobile communication systems
We focus on the challenges for maximizing the system performance with fairness among user equipments (UEs) in heterogeneous networks (HetNet) which include the configuration design of the almost blank subframes (ABS) pattern and the resource allocation for macro UEs and pico UEs in terms of the time domain resource, i.e., subframe configuration including protected subframe and normal subframe where the resource is located in the time domain, and the frequency domain resource, i.e., subcarrier allocation to multiple UEs where this resource is located in the frequency domain
(11) denotes that each resource blocks (RBs) in the macro eNB is only allocated to one macro UE; each RB in one eNB is not allowed to be shared among UEs served in the eNB; Eq (12) denotes that each RB in the pico eNB

Summary

Introduction

Orthogonal frequency division multiple access (OFDMA) system has been chosen for the next-generation broadband wireless system standards [1] in order to satisfy the growing demands on the high data traffic in the mobile communication systems. (11) denotes that each RB in the macro eNB is only allocated to one macro UE; each RB in one eNB is not allowed to be shared among UEs served in the eNB; Eq (12) denotes that each RB in the pico eNB is only allocated to one pico UE; Eq (13) means that each subframe is only classified as either the normal subframe or the protected subframe; the sum of ε[i]and ε∗[i] for a particular subframe i is equal to 1; Eq (14) implies that one pico UE can only be in the normal UE set or the protected UE set This resource allocation considered in this paper contains two main challenges: (a) configuration of the ABS pattern, i.e. determines the values of ε[i]. After the development of the configuration of an ABS pattern, the UE grouping design will be shown

Proposed UE grouping strategy

Proposed joint allocation scheme

Findings

Conclusions