Performance Analysis of an OFDM PHY Scheme with Zero Forcing Equalizer Using Software Defined Radio Platform and USRP

EMITTER International Journal of Engineering Technology Vol.2, No.1, June 2014 ISSN: 2443-1168 Performance Analysis of an OFDM PHY Scheme with Zero Forcing Equalizer Using Software Defined Radio Platform and USRP Ahmad Zainudin, Amang Sudarsono, I Gede Puja Astawa Postgraduate Applied Engineering of Technology Division of Electrical Engineering, Dept. of Electrical Engineering Electronic Engineering Polytechnic Institute of Surabaya (EEPIS) Kampus PENS, Jalan Raya ITS, Sukolilo 60111, Indonesia Email : {zai, amang, puja}@pens.ac.id Abstract We present an implementation of Zero Forcing (ZF) equalizer in OFDM scheme using Software Defined Radio platform whereas NI USRP-2920 as the Radio Frequency (RF) front-end. ZF equalizer is employed to achieve reliable system at the receiver. Center frequency used for data transmission is 915 MHz. The reliability transmission and the performance of ZF equalizer are measured in term of different symbol mapping (i.e., M-PSK and M-QAM). The IQ rate determines the bandwidth available, whereas good performance is achieved with IQ rate less than 1 MHz.ZF equalizer achieves good performance when using BPSK, QPSK and 16-QAM modulation techniques. By applying ZF equalizer, bit error on BPSK and QPSK modulations can be reduced from 29,16% and 39,06% into 0%. This advantage of ZF equalizer also is able to press the bit error on 16QAM and 64-QAM modulations into 3,125% and 8,85%, respectively. Keywords: OFDM,SDR, USRP,Zero Forcing Equalizer 1. INTRODUCTION Recently, demand of bandwidth is increasing, especially for mobile devices. Orthogonal Frequency Division Multiplexing (OFDM) is introduced as one of solutions to enable bandwidth efficiency and robustness due to intersymbol inteference (ISI) in the consequence of multipath fading environment [1]. The principle of OFDM is dividing high rate data stream into parallel low rate data streams using Fast Fourier Transform (FFT)[2]. Moreover, OFDM scheme is widely used in wireless communication system, such as IEEE 802.11 standard, cellular communication (e.g., WiMAX and LTE Advanced) and digital broadcasting standard (e.g., DVB-T). In addition, OFDM is combined by modulation with more bits per symbol to increase data Copyright © 2014 EMITTER International Journal of Engineering Technology - Published by EEPIS 26 Volume 2, No. 1, June 2014 37 Figure 7. The compairing of bit error for unequalized data and use ZF equalizer 7. CONCLUSION AND FUTURE WORK A LabVIEW application has been developed to implement OFDM communication system use BPSK, QPSK, 16-QAM and 64-QAM modulation. Moreover, ZF equalizer is employed to achieve reliable system. The IQ rate determine the bandwidth available, but in this experiment good performance is achieved with IQ rate less than 1 MHz. BPSK, QPSK and 16-QAM are more resistant with noise enviroment than 64-QAM. The good performance of ZF equalizer is achieved when is modulated using BPSK, QPSK and 16-QAM. By applying ZF equalizer can reduce bit error from 29,16% and 39,06% into 0% when use BPSK and QPSK modulation. Whereas, the bit error can be pressed became 3,125% and 8,85% when 16-QAM and 64-QAM modulation be used. Next experiment will constructed OFDM PHY scheme with MMSE equalizer to increase the reliability OFDM system which be implemented use USRP as RF front end. REFERENCES [1] Y. Sun,Bandwidth-Efficient Wireless OFDM, IEEE Journal on selected area in Communication, Vol. 19, No. 11, November 2001. [2] M. Ergen,Mobile Broadband Including WiMAX and LTE, pp109, ISBN: 978-0-387-68189-4, New York, USA, Springer Science+Business Media, LLC 2009. [3] S. Costanzo, F. Spadafora, A. Borgia, H. O. Moreno, A. Costanzo, G. Di Massa, High Resolution Software Defined Radar System for Target Detection, Journal of Electrical and Computer Engineering, Volume 2013. [4] A. Marwanto, M. A. Sarijari, N. 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[16] National Instrument Data sheet, NI USRP-2920, NI USRP-2921, http://indonesia.ni.com, accessible April, 2014. EMITTER International Journal of Engineering Technology, ISSN: 2443-1168  (...truncated)