J. Today’s Ideas - Tomorrow’s Technol.

Performance Enhancement of DS-CDMA System using Extended BPSK Modulation Scheme

Barkha Pandey, Raghu Harsh Kalia, Monica Kaushik, Monika Arora

KEYWORDS

Additive White Gaussian Noise, Bandwidth Efficiency, Binary Phase Shift Keying, Bit Error Rate, Direct Sequence-Code Division Multiple Access, Extended BPSK, Modulation.

PUBLISHED DATE December 2016
PUBLISHER The Author(s) 2016. This article is published with open access at www.chitkara.edu.in/publications
ABSTRACT

In a last few decades there has been tremendous growth and a drastic rise in wireless communication technologies. The major issue that the world is facing today with the advent of so many sophisticated wireless communication devices is efficient utilization of the spectrum. Spectrum efficiency comes together with a tradeoff factor of energy consumption. Thus, the need of the hour is an energy and bandwidth efficient technique. DS-CDMA is one of the competitive and most investigated technique in wireless communication which caters the large demand at the same time with limited bandwidth. Existing modulation techniques does not promise to provide better performance in case of higher noise. Therefore, one looks for a better BER stipulated modulation format to improve and enhance the performance of the system. This article revisits conventional Binary phase shift keying method and compares its performance in terms of BER with a special Extended Binary Phase Shift Keying (EBPSK) modulation format for a DS- CDMA system. EBPSK scheme is flexible and simple which is easily integrated in a network and assures improved and enhanced performance.

INTRODUCTION

Recent advancements in the field of wireless communication exhibit an exponential increase in the demand in terms of users, energy consumption as well as the frequency spectrum. The need of the hour is to alleviate the spectrum crisis and energy consumption problem. The ever increasing demand for better performance compels us to look in to the basic modulation technique [1-2]. Advancement in newer technology requires gaining maximum throughput using limited bandwidth that comes with efficient utilization of the available resources. CDMA (Code Division Multiple Access) is a communication technique that allows a number of users to access the same channel simultaneously, wherein DS-CDMA (Direct sequence CDMA) is its most investigated application [3]. DS-CDMA system is a widely used communication system that faces multiple user access interference as a challenge which causes degradation in the system performance. To suffice the growing need for high data rate communication systems, a new technique which can efficiently to the work has evolved which promises to offer high spectrum efficiency and high data rates [4, 5]. In this paper, the performance of a DSCDMA system is evaluated in terms of BER using conventional BPSK (Binary Phase Shift Keying) modulation technique, and another modulation technique referred to as extended binary phase shift keying (EBPSK) [5]. EBPSK is an ultra narrowband modulation technique which offers better energy and spectral efficiency [6]. Here, the performance of a DS-CDMA system is evaluated and simulated using BPSK modulation in terms of ratio of SNR (Signal-to-noiseratio) and BER (Bit Error Rate). Further, evaluation is done using EBPSK as a modulation technique and corresponding enhanced results are observed in presence of AWGN noise. This work sums up the advantage of taking EBPSK as a modulation technique over BPSK modulation scheme. It is known that BER for DS-CDMA system under PSK is better than ASK and FSK [7].

Section II re-considers the BPSK modulation scheme and introduces the EPBPSK modulation method and its explanation. Section III takes up BER (bit error rate) as a parameter for measuring the performance of DS-CDMA system with two different modulation formats (BPSK & EBPSK)

Page(s) 172-180
URL http://dspace.chitkara.edu.in/jspui/bitstream/1/782/1/jotitt.2016.42009.pdf
ISSN Print : 2321-3906, Online : 2321-7146
DOI 10.15415/jotitt.2016.42009
CONCLUSION

In this paper we have addressed a number of advantages of EBPSK scheme for the present day scenario of Wireless Communication. EBPSK method promises to provide lesser energy consumption and better spectral efficiency. However, this work has taken up conventional BPSK modulation scheme and compared its BER performance with special extended BPSK scheme for a DS-CDMA system. The reviewed literature and simulated results shows better performance of EBPSK scheme for a DS-CDMA system. The simulated results depict that there is a significant improvement in the BER performance at higher values of Eb/No. It is a technique which is simple to implement and provides better BER operation with few changes in representation of Bit “1” and “0”.

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