Energy-Efficient Resource Allocation for Fractional Frequency Reuse in Heterogeneous Networks

Kemal Davaslioglu,Ender Ayanoglu,Cemil Can Coskun

doi:10.1109/twc.2015.2438826

Kemal Davaslioglu, Ender Ayanoglu + Show 1 more

Open Access

https://doi.org/10.1109/twc.2015.2438826

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Journal: IEEE Transactions on Wireless Communications	Publication Date: Oct 1, 2015
Citations: 29	License type: publisher-specific, author manuscript

Affiliation: University of California, Irvine

Abstract

Next generation wireless networks face the challenge of increasing energy consumption while satisfying the unprecedented increase in the data rate demand. To address this problem, we propose a utility-based energy-efficient resource allocation algorithm for the downlink transmissions in heterogeneous networks (HetNets). We consider the fractional frequency reuse (FFR) method in order to mitigate the intra- and inter-cell interference. The proposed algorithm divides the resource allocation problem into frequency and power assignment problems and sequentially solves them. The proposed power control algorithm uses the gradient ascent method to control the transmit power of macrocell base stations (MeNBs) as most of the power in the network is consumed there. We present the optimality conditions of the resource allocation problem and the convergence of the proposed algorithm. In order to mitigate the inter-cell interference further, we study the interference pricing mechanisms and obtain an upper bound to the maximum energy efficiency problem including the inter-cell interference contributions. The performance of the proposed algorithm is studied in a Long Term Evolution (LTE) system. Our simulation results demonstrate that the proposed algorithm provides substantial improvements in the energy efficiency and throughput of the network. It is also shown that interference pricing provides only marginal improvements over the proposed algorithm.

Highlights

Energy efficiency is an important issue in the generation wireless networks
We consider the case with the fixed fractional frequency reuse (FFR) boundaries, in which the cell radius that maximizes the average energy efficiency is chosen through enumeration methods
For the FFR method, there are 32 resource blocks in the subband A and 6 resource blocks are allocated to subbands B, C, and D, i.e., NMC = 32, NMX = 6, NPC = 12, and NPX = 44 [6]

Summary

Introduction

The high data rate demands of the LTE and LTE-Advanced standards bring the hidden cost of increasing energy consumption These have been studied in the literature under the topic of “Green Communications” [1]. Several methods have been investigated and standardized to increase the energy efficiency of the networks, see, e.g., [1]–[5] Among these solutions, we study the FFR method in this paper to reduce both the intra- and inter-cell interference. These works consider the static power consumption along with the transmit power to develop better link adaptation schemes In our paper, this problem is addressed but in a large scale such that the energy efficiency of the complete network is maximized. A recent study in [7] proposed a novel FFR scheme for HetNet deployments with sectorized macrocell base stations, we use the same scheme

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