A Cooperative Phase-Steering Technique with On-Off Power Control for Spectrum Sharing-Based Wireless Sensor Networks.

Sangku Lee,Bang Chul Jung,Janghyuk Yoon

doi:10.3390/s20071942

Abstract

With the growth of the number of Internet of Things (IoT) devices, a wide range of wireless sensor networks (WSNs) will be deployed for various applications. In general, WSNs are constrained by limitations in spectrum and energy resources. In order to circumvent these technical challenges, we propose a novel cooperative phase-steering (CPS) technique with a simple on-off power control for generic spectrum sharing-based WSNs, which consists of a single secondary source (SS) node, multiple secondary relay (SR) nodes, a single secondary destination (SD) node, and multiple primary destination (PD) nodes. In the proposed technique, each SR node that succeeds in packet decoding from the SS and for which its interference power to the PD nodes is lower than a certain threshold is allowed to transmit the signal to the SD node. All SR nodes that are allowed to transmit signals to the SD node adjust the phase of their transmit signal such that the phase of received signals at the SD node from the SR nodes is aligned to a certain angle. Moreover, we mathematically analyze the outage probability of the proposed scheme. Our analytical and simulation results show that the proposed technique outperforms the conventional cooperative relaying schemes in terms of outage probability. Through extensive computer simulations, it is shown that the analytical results match well with the simulated outage probability as a lower bound.

Highlights

The Internet of Things (IoT) concept can be defined as all devices such as computing devices, mechanical and digital machines, objects, animals, or people in the world will be interconnected to collect and exchange data remotely for interaction with one another and with other devices and services over the Internet [1]
As part of an IoT topology, wireless sensor networks (WSNs) have been a key enabler of IoT, which can be described as a network of devices that can cooperatively sense the environment and may control the devices through a wireless link to communicate between persons, computers, or the surrounding environment [4]
We compare the performance of the proposed cooperative phase steering (CPS) technique with the conventional opportunistic relay selection (ORS) [20,21] scheme in a spectrum sharing-based WSNs in terms of 2 = 0 dB, outage probability and throughput

Summary

Introduction

The Internet of Things (IoT) concept can be defined as all devices such as computing devices, mechanical and digital machines, objects, animals, or people in the world will be interconnected to collect and exchange data remotely for interaction with one another and with other devices and services over the Internet [1]. Cooperative communication is one of the most important techniques to overcome the power limitation and improve the physical-layer performances of WSNs by providing additional spatial diversity with multiple relay nodes [19]. In this paper, as the main contributions, we modify the conventional CPS scheme for the spectrum sharing-based WSNs. Most importantly, only the secondary relay node that impacts the interference power less than certain interference constraints to the primary destination node can transmit the signal to the secondary destination node with the CPS scheme.

System Model

CPS Technique for Spectrum Sharing-Based WSNs

Numerical Results and Analysis

Conclusions