Downlink capacity of OFDMA-CR based 5G femtocell networks

Joydev Ghosh,Dushantha Nalin K Jayakody,Marwa Qaraqe

doi:10.1016/j.phycom.2018.04.016

Joydev Ghosh, Dushantha Nalin K Jayakody + Show 1 more

Open Access

https://doi.org/10.1016/j.phycom.2018.04.016

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Abstract

This research work explores small cell densification as a key technique for next generation wireless network (NGWN). Small cell densification comprises space (i.e, dense deployment of femtocells) and spectrum (i.e., utilization of frequency band at large). The usage of femtocells not only improves the spectral efficiency (SE) of the Heterogeneous two-tier networks against conventional approach, but also it alleviates outage probability and enhances the achievable capacity. We yield an analytical framework to establish the density of the femto base station (FBS) to a monotonically increasing or decreasing function of distance or radius, respectively. This ensures the enhanced performance in spectrum sharing Orthogonal Frequency Division Multiple Access (OFDMA) femtocell network models. We also illustrate the influence of active Femto users (i.e., users in femtocells, and they are usually low mobility and located closer to the cell center with less fading), cluster size (i.e., a group of adjacent macrocells which use all of the systems frequency assignments) via simulation results.

Highlights

The fourth generation (4G) wireless networks that are being deployed worldwide cannot fulfill the increasing requirement of smart technology facilitated device, i.e., smart watch, tablets and n-computing devices, in the era [1], [2]
As there is no interference within the cell, we let consider that the received interference for the reference macro Macro user (MU) utilizing sub-channel n is from adjacent macro base station (MBS) and nearby femto base station (FBS)
This section uses simulation outcomes to validate the accuracy of the proposed analytical models of Orthogonal Frequency Division Multiple Access (OFDMA)-cognitive radio (CR) based femtocell networks

Summary

INTRODUCTION

The fourth generation (4G) wireless networks that are being deployed worldwide cannot fulfill the increasing requirement of smart technology facilitated device, i.e., smart watch, tablets and n-computing devices, in the era [1], [2]. The concept of small cell wireless networks (femtocells, picocells, and macrocells), is attractive to mobile operators due to their ability to provide better indoor or outdoor local area system capacity and network coverage [4]. The Doppler frequency offset in high mobility scenarios, where the pilot channel fluctuates at the time of communication, destroys the orthogonality of subcarriers [6] This contributes to OFDMA sensitivity to inter carrier interference (ICI). The major contributions of the paper can be summarized as: 1) It is shown that the capacity set by the interfering transmitter is consistent with the signal to interference plus noise ratio, (S/(I+ N)) at the sufferer receiver This approach needs information of several transmission factors of the interfering signal, such as the degree of modulation, OFDMA, sub-carrier spacing etc.

SYSTEM MODEL

DL Spectrum sharing

SIMULATION RESULTS AND DISCUSSION

CONCLUSION