Performance Analysis of Circular 8-QAM Constellation with MMSE Equalizer for OFDM System Using USRP

  • Muh. Alfan Taufiqurrahman Politeknik Elektronika Negeri Surabaya
  • I Gede Puja Astawa Politeknik Elektronika Negeri Surabaya
  • Amang Sudarsono Politeknik Elektronika Negeri Surabaya
Keywords: OFDM, Circular-8QAM, USRP, MMSE Equalizer


Bandwidth is very important in communication system, and it is a limited resource. In order to save the limited bandwidth resource, high order M-ary modulation is widely employed in modern communication and broadcasting systems. In Orthogonal Frequency Division Multiplexing (OFDM), fading environment lead to a loss of orthogonality between the subcarriers. In this paper, we present the performance analysis of circular 8-Quadrature Ampilutude Modulation (QAM) constellation for Orthogonal Frequency Division Multiplexing (OFDM) system. We also combine the system with Minimum Mean Square Error (MMSE) equalizer to mitigate the effect of Inter Symbol Interference (ISI). Then, all of this system is implemented practically using Universal Software Radio Peripheral (USRP). The performance of circular 8-QAM and MMSE equalizer is evaluated by comparing with other 8-QAM modulation models such as circular-Zero Forcing (ZF), star-ZF, Square-ZF, Star-MMSE, and Square-MMSE. The performance of circular 8-QAM with MMSE equalizer is  better than the other combinations. Bit Error Rate (BER) graph shows that the performance of circular-MMSE is better than star-MMSE. The performance improvement using circular-MMSE is about 1.6%. The performance will decrease when the distance is increased. The performance of this system is greatly affected by the distance between transmitter and receiver.


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Bernard Sklar. Digital Communications: Fundamentals and Applications (2 edition). New Jersey: Prentice Hall PTR, 2001.

Laia Nadal, Josep Maria Fà brega, Javier Vílchez, and Michela Svaluto Moreolo, Experimental Analysis of 8-QAM Constellations for Adaptive Optical OFDM Systems, IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 28, NO. 4, FEBRUARY 15, 2016

Y. Li, S. Xu, and H. Yang, “Design of Circular Signal Constellations in the Presence of Phase Noise,†in Proc. Int. Conf. on Wireless Communication.,Networking and Mobile Computing, Oct. 2008

Pollet, T., Spruyt, P., Moeneclaey, M., “The BER performance of OFDM systems using non-synchronized sampling,†Proc. IEEEGLOBECOM, vol.1, pp.253-257, 1994

Nisha Achra, Garima Mathur, Prof. R.P. Yadav, Performance Analysis of MIMO OFDM System for Different Modulation Schemes under Various Fading Channels, International Journal of Advanced Research in Computer and Communication EngineeringVol. 2, Issue 5, May 2013

Abirami M, Gandhiraj R, Soman K. P, Performance Analysis of Real Time OFDM Based Communication System Using GNU Radio and USRP, International Journal of Advanced Research in Computer Scienceand Software Engineering, ISSN : 2277 128X, Volume 3, June 2013

A. Y. F. Youssef, K. M. H. Hassan, M. G. Mostafa, M. T. Saad, M.Khairy,Implementation of a wireless OFDM system using USRP2 and USRP N210 Kits,Graduation Project Report,Faculty ofEngineering,CairoUniversity,Giza,Egypt,July 2012

Duc Toan Nguyen, Impelementation of OFDM System using USRP and GNU Radio, University of Wollonggong, 2013.

R. Rios-Müller, J. Renaudier, P. Tran, G. Charlet, Experimental Comparison of Two 8-QAM Constellations at 200 Gb/s over Ultra Long-Haul Transmission Link, ECOC 2014, Cannes – France

A. Kanchan, S. Dwivedi, Comparison of BER Performance in OFDM Using Different Equalization Techniques, International Journal ofEngineering and Advanced Technology (IJEAT), ISSN:2249-8958,Volume-1, Issue-6, August 2012

Beena R. Ballal, Ankit Chadha, Neha Satam, Orthogonal Frequency Division Multiplexing and its Applications, International Journal of Science and Research (IJSR), India Online ISSN: 2319-7064, Volume 2 Issue 1, January 2013

Quadrature Amplitude Modulation,, accessible April 2016.

J. G. Proakis, “Digital Communications,†Fourth edition, New York: McGraw-Hill, 2001

Michael McLaughlin, Comparison of 8-star QAM and other 8-point Constellations,IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs), 2008, “MIMO-OFDM with Different Equalizationâ€, access at 10 June 2016

How to Cite
Taufiqurrahman, M. A., Astawa, I. G. P., & Sudarsono, A. (2016). Performance Analysis of Circular 8-QAM Constellation with MMSE Equalizer for OFDM System Using USRP. EMITTER International Journal of Engineering Technology, 4(2), 259-276.