Orthogonal Frequency Division Multiplexing (OFDM) is one of the techniques for high speed data rate communication with main consideration for 4G and 5G systems. In OFDM, there are several mapping schemes which provide a way of parallel transmission. In this paper, comparisons of mapping schemes used by some standards have been made and also has been discussed about the performance of the non-conventional modulation technique. The Comparisons of Bit Error Rate (BER) performances for conventional and non-conventional modulation schemes have been done using MATLAB software. Mentioned schemes used in OFDM system can be selected on the basis of the requirement of power or spectrum efficiency and BER analysis.<\/p>\r\n","references":"[1] Performance in the Presence of a Nonlinear Amplifier And Phase Noise,\" IEEE Trans. Commun., Vol. 50,pp. 462-472, March 2002.\r\n[2] Imdadul Islam, Siddique Hossain, \"Comparision of traffic performance of QPSK and 16-QAM modulation techniques for OFDM system,\" Journal of Telecommunications and Information Technology, pp. 147\u00ac152, Jan 2005.\r\n[3] Roslina Mohammad, NuzliMohammad Anas, and Kaharudin Dimyati, \"Design and Implementation of Pi\/4 Shift D-QPSK Baseband Modem using DSP Techniques,\" IEEE, pp. 1-5, 2006.\r\n[4] Nico Toender, Herman Rohling, \"DAPSK Schemes for Low- Complexity OFDM Systems,\" IEEE international Symposium on Personal, Indoor, and Mobile Radio Communications, pp. 735-739, 2005.\r\n[5] Peng Tan, Norman C. Beaulieu, \"Exact BER Analysis of a Pi\/4- DQPSK OFDM System in the Presence of Carrier Frequency Offset over Frequency Selective Fast Rayleigh Fading Channels,\" IEEE pp. 488-494, 2005.\r\n[6] Thibault L. and Le M. T., \"Performance Evaluation of COFDM for Digital Audio Broadcasting, Part I: Parametric Study,\" IEEE Transaction on Broadcasting, vol. 43, No. 1, pages 64-75, March 1997.\r\n[7] Leonrd E. Miller, Thong S. Lee, \"BER Expressions for Differentially Detected Pi\/4 DQPSK Modulation,\" IEEE Trans. On Commun., vol. 46, pp. 71-81, Jan 1998.\r\n[8] P.A. Baker, \" Phase-modulation Data Sets For Serial Transmission at 2000 and 2400 Bits per second,\" in Part 1, AIEE Trans. On Communication Electronics, July 1962.\r\n[9] C. L. Liu and K. Feher, \"7t\/4- QPSK modems for Satellite sound\/Data broadcast systems,\" IEEE Trans. Broadcasting , vol, 37 No.1, pp 1-8, March 1991.\r\n[10] K. Feher, \"Modems for emerging digital Cellular Mobile Radio Systems,\" IEEE Trans. Veh. Technology,Vol. 40 No. 2, pp 355-365, May 1991.\r\n[11] S. Chennakeshu and G. J. Saulnier,\"Differential Detection of Pi\/4- shifted-DQpsk for Digital Cellular Radio,\"IEEE Trans. Veh. Technol., vol. 42, pp. 46-57, Feb. 1993.\r\n[12] C. L. Liu and K. Feher, \"Performance of Non- coherent Pi\/4-QPSK in a Frequency- Selective Fast Rayleigh Fading Channel\", Proceedings of IEEE ICC'90, Atlanta, Georgia, April 1990.\r\n[13] C. L. Liu and K. Feher, \"Noncoherent Detection of Pi\/4-QPSK Systems in a CCI-AWGN Combined Interference Environment,\" in Proceedings of IEEE VTC, 1989.\r\n[14] Y. Yamao, S. Saito, H. Suzuki and T. Nojima, \"Performance of Pi\/4-QPSK Transmission for Digital Mobile Radio Applications,\" in Proceedings of IEEE GLOBECOM, 1989.\r\n[15] S. Ariyavisitakul and T. P. Liu, \"Characterizing the Effects of Nonlinear Amplifiers on Linear Modulation for Digital Portable Radio Communications,\" IEEE Trans. Technol., vol. 39, pp.383-389, Nov. 1990.\r\n[16] G. Zimmermann, M. Rosenberger, and S. Dostert, \"Theoritical bit error rate for uncoded and coded data transmission in Digital Audio Broadcasting,\" in Proceeding IEEE International Conference on Communications, Dallas, USA, pp. 297-301, June 1996.\r\n[17] M. Lott, \"Comparision of Frequency and Time Domain Differential Modulation in an OFDM System for Wireless ATM,\" in Proceeding IEEE 49th VTC, Houston, USA, May 1999.\r\n[18] J. Lu, T. T. Tjhung, F. Adachi and C. L. Huang, \"BER Performance of OFDM-MDPSK System in frequency- selective Rician fading with diversity reception,\" IEEE Trans. Veh. Technol., vol. 49, pp. 1216-1225, July 2000.\r\n[19] K. Zhong, T. T. Tjhung and F. Adachi, \"A general SER formula for an OFDM System with MDPSK in frequency domain over Rayleigh fading channels,\" IEEE Trans. Commun., vol. 52, pp. 584-594, Apr 2004.\r\n[20] Y. Akaiwa and Y. Nagata, \"Highly Efficient Digital mobile communications with a linear modulation mmethod,\" IEEE J. Select. Areas Commun., vol. SAC-5, pp. 890-895, June 1987.\r\n[21] S. H. Goode, H. L. Kazecki and D. W. Dennis, \"A Comparision of limiter- discriminator, delay, and coherent detection for Pi\/4-QPSK,\" in Proc. IEEE Veh. Technol. Conf., Orlando, FL, pp. 687-694, May 1990.\r\n[22] Xiong Fuqin, Digital modulation techniques. London: Artech House, 2000,2nd Edition, ch. 4, pp. 170-176.","publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 57, 2011"}