International Journal of Technology Enhancements and Emerging Engineering Research (ISSN 2347-4289)

IJTEEE >> Volume 2 - Issue 8, August 2014 Edition

International Journal of Technology Enhancements and Emerging Engineering Research  
International Journal of Technology Enhancements and Emerging Engineering Research

Website: http://www.ijteee.org

ISSN 2347-4289

Adaptive OFDM Modulation Used For SDR

[Full Text]



Gunjal Pooja Raosaheb, R.R. Bhambare



Index Terms: Software Defined radio, Adaptive modulation, Channel SNR, BER , OFDM.



Abstract: Software defined radio (SDR) is the future trend for mobile communication. A SDR is supposed to facilitate high speed multimedia application for future mobile standards. Adaptive modulation forms an integral part of SDR system with robust and high data rate capability. Here we have analyzed adaptive modulation scheme with their performance in changing channel condition. The modulation scheme studied for adaptive modulation are BPSK, QPSK 16QAM , 32 QAM ,64 QAM . Different order modulations and different coding schemes, allow to send more bits per symbol, thus gaining higher throughputs and better spectral efficiencies. But it must also be noted that when using a modulation technique such as 64-QAM with less overhead bits, better signal-to-noise ratios (SNRs) are necessary to overcome any Intersymbol Interference (ISI) and also maintain a certain bit error ratio (BER). The use of adaptive modulation gains wireless technologies to yielding higher throughputs while also covering long distances. This paper focusing on the physical layer design (i.e. Modulation), here the various used modulation type will be implemented in a single Matlab function that can be called with the appropriate coefficients. A comparison will be made in terms of SNR and BER relation.



[1] Mohammad Wasif, Mamoon Elahi “Analysis and Implementation of Adaptive Modem for SDR” Chirag Sanghavi School of Electrical Sciences, VIT University, Vellore – 632014, India. 2007.

[2] Ms. Nita J.Borkar , Mr. Dattatray.S. Bormane BER “Performance of OFDM System with Adaptive Modulation”
[3] IEEE transaction on OFDM System with Adaptive Modulation , 2012.

[4] Maria Katrina D. Guevara, Ivan Kenneth A. Wang, Rhandley D. Cajote and Romarie U. Lorenzo⋆ Digital Signal Processing Laboratory, Wireless Communications Engineering Laboratory , Electrical and Electronics Engineering Institute, University of the Philippines – Diliman “ Physical Layer Implementation of Orthogonal Frequency Division Multiplexing for Software Defined Radio on FPGA” 2011.

[5] Y.S.Choo, et.al., MIMO-OFDM Wireless Communications with MATLAB. IEEE Press, 2010.

[6] Arne Svensson – “An Introduction to Adaptive QAM Modulation Schemes for Known and Predicted Channels” - Proceedings of the IEEE on Adaptive modulation and transmission in wireless system | Vol. 95, No. 12, December 2007

[7] Suvra S. Das, Elisabeth De Carvalho, Ramjee Prasad –“Performance Analysis of OFDM Systems with Adaptive Sub Carrier Bandwidth” - (IJCSIS) International Journal of Computer Science and Information Security, Vol. 5, No.1, 2009.

[8] Bang Chul Jung, Jae Kyun Kwon, Hu Jin, and Dan Keun Sung – “Sub-band Spreading Technique for Adaptive Modulation inOFDM Systems” - Journal Of Communications And Networks,Vol. 10, No. 1, March 2008

[9] Jaekyoung Moon and Sangjin Hong – “Adaptive Code-Rate and Modulation for Multi-User OFDM System in Wireless Communications” - IEEE transaction on Vehicular Technology vol. 4, pp-1943-1947,2002

[10] Sami Ahmed Haider and Khalida Noori-“Adaptive Turbo Coded OFDM” -Journal of Digital Information Management Volume 5 Number 6 _ December 2007

[11] J.Faezah, K.Sabira]-“Adaptive modulation with OFDM system”- International Journal of Communication Networks and Information Security- Vol. 1, No. 2, August 2009

[12] Tomoya Urushihara, Takenori Sakamoto, Kentaro Miyano, Katsuaki Abe, Takashi Matsuoka,” Performance Analysis of Adaptive Modulation Algorithm using Pseudo Bit Error Rate on IEEE 802.11a”, IEEE CCNC 2006 proceedings.

[13] Digital modulation in a communications system [Hewlet Packard application note]

[14] Bandwidth efficient modulation [CCSDS 413.0-G-1 april 2003]

[15] Jeffrey M. Fifield , thesis of “A Software De¯ned OFDM Modulator” , B.S., University of Michigan, 2000.