Collaborative reception technique in wireless sensor networks using adaptive antennas

Marcelo Ac Fernandes

doi:10.1186/1687-1499-2014-225

Abstract

This work describes a new collaborative reception strategy designed to improve the performance and transmission capacity of the nodes of a wireless sensor network. The technique involves the use of a linear array of adaptive antennas, consisting of a set of sensors that operate in a collaborative manner as an adaptive spatial processor. It can be characterized as a single-input multiple-output (SIMO) system and exploits the spatial diversity of the sensors, which significantly improves performance in terms of energy consumption and transmission capacity. The principles of the proposed scheme are presented, together with bit error rate (BER) performance curves. The advantage of the technique is that it enables several sensors to transmit at very low powers, hence reducing energy consumption.

Highlights

The signals in wireless digital communication systems can be corrupted by various factors, especially thermal noise and multipath, resulting in frequency-selective fading
Collaborative transmission utilizing coded orthogonal frequency division multiplex (COFDM) [2] was presented in [14], where a source sensor transmitted its data to a group of repeater sensors that re-transmitted the signal collaboratively to another receptor sensor, forming a virtual COFDM system transmitting the same information in all the carriers
A new strategy was developed based on a collaborative scheme in order to implement a linear array of adaptive antennas for application in wireless sensor networks

Summary

Introduction

The signals in wireless digital communication systems can be corrupted by various factors, especially thermal noise and multipath, resulting in frequency-selective fading. Collaborative transmission utilizing coded orthogonal frequency division multiplex (COFDM) [2] was presented in [14], where a source sensor transmitted its data to a group of repeater sensors that re-transmitted the signal collaboratively to another receptor sensor, forming a virtual COFDM system transmitting the same information in all the carriers This system exploited the spatial diversity of the sensors; it was assumed that the time delay for transmission between the re-transmitters and the receptor sensor was greater than the largest channel delay. Validation of the CLA, and evaluation of its performance and reliability in a wireless sensor network, was achieved by conducting simulations for 4-QAM, 16-QAM, and 64QAM digital communication systems, without channel encoding, at a rate of Rb = 10 kbps with a carrier frequency fc = 2.5 GHz. Curves were plotted of BER as a function of Eb/N0, which denotes the relation between bit energy and the spectral power density of the noise, as CLA with K=2 and N =10%. All the other parameters used in the simulations are presented in Table 2 [7,8,9,23,24]

First scenario

Conclusions