کاهش PAPR با استفاده از تکنیک‌های پیش کدگذاری و کامپندینگ برای سیستم‌های OFDM
الموضوعات :بهروز قدیمی 1 , حسین مومن زاده حقیقی 2 , علیرضا ملاح زاده 3
1 - دانشگاه ازاد اسلامی ، واحد بوشهر ؛ گروه مهندسی برق ، بوشهر ، ایران
2 - استادیار، دانشگاه ازاد اسلامی ، واحد بوشهر ؛ گروه مهندسی برق ، بوشهر، ایران
3 - موسسه آموزش عالی زند دانش گستر، شیراز، ایران
الکلمات المفتاحية: OFDM, PAPR, پیش کدگذاری, کامپندینگ, Precoding, Companding,
ملخص المقالة :
در سال‌های اخیر نیاز به انتقال قابل اطمینان داده‌های دیجیتالی رو به افرایش است و گسترش شبکه‌های اطلاعاتی با سرعت بالا و شبکه‌های بیسیم در زمینه تجاری دولتی و شخصی باعث گردید که این امر موردتوجه قرار گیرد. OFDM از مدولاسیون‌های چند حاملی و متشکل از چند ساب کاریر می‌باشد که به صورت عمود بر هم مدوله شده اند. از معایب مدولاسیون های چند حاملی نظیر OFDM، بزرگ بودن نسبت پیک به توان متوسط یا PAPR در سیگنال خروجی فرستنده می باشد. بزرگ بودن PAPR سیگنال ارسالی، باعث می شود تا تقویت کننده های با محدوده عملکرد خطی وسیعتری لازم شود که به صرفه نیست و اگر از تقویت کننده های توان با ناحیه عملکرد خطی کم استفاده شود باعث اعوجاج داخل باند و تشعشع خارج از باند سیگنال ارسالی می شود.بنابر این در این مقاله از دو تکنیک پیش کدینگ و کامپندینگ قانون μ برای کاهش PAPR استفاده میشود. مطالعات بیشتری با استفاده از روش‌های مختلف مدولاسیون و تعداد زیرحامل های متفاوت انجام شده است. کاهش قابل ملاحظه در مقادیر PAPR با استفاده از این روش‌های حاصل شده است. و کارایی این روشها با یکدیگر مقایسه شده است.
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[2] S. Sengar, and P. P. Bhattacharya, “Performance Improvement in OFDM System by PAPR Reduction,” Signal & Image Processing: An International Journal (SIPIJ), vol.3, No.2, April 2012.
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[4] M.Chauhan, A.Chobey, “PAPR Reduction in OFDM system Using Tone Reservation Technique,” International Journal of Computer Technology and Electronics Engineering (IJCTEE), vol. 2, no. 4, August 2012.
[5] D.Xie, S.Yang, L. Qi and X. Mu, “PAPR Reduction Of FrFT-Based MB-OFDM Ultra Wide Band Signals”, in proc. 4th International Conference on Wireless Communications, Networking and Mobile Computing, Oct 2008.
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[7] P. Elavarasan, Dr.G. Nagarajan and A.Narayanan, “P APR Reduction in MIMO-OFDM Systems using Joint Channel Estimationand Precoding”, in proc. IEEE International Conference on Advanced Communication Control and Computing Technologies (ICACCCT), 2012.
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[11] Y.Jiang, “New companding Transform for PAPR Reduction inOFDM,” IEEE Communications Letters, vol. 14, no. 4, pp. 282–284, April 2010.
[12] Md. I. Abdullah, Md. Z Mahmud, Md. S. Hossain and Md.N. Islam, “Comparative Study of PAPR Reduction Techniques in OFDM,” ARPN Journal of Systems and Software, vol. 1, NO. 8, November 2011.
[13] P. Elavarasan, Dr. G.Nagarajan and A Narayanan, “PAPR Reduction in MIMO-OFDM Systems using Joint Channel Estimation and Precoding,” International Conference on Advanced Communication Control and Computing Technologies (ICACCCT),vol. 3, no. 1, January 2012.
[14] Z. Wang, “Combined DCT and Companding for PAPR Reduction in OFDM Signals,” Journal of Signal and Information Processing, vol. 2, pp. 100-104, 2011.
[15] T. Jiang, Y. Yang and Y.H. Song, “Companding Technique for PAPR Reduction in OFDM Systems Based on An Exponential Function”, in proc. IEEE GLOBECOM, 2005.
[16] T. Deepa, R. Kumar, “Performance Analysis of μ-law Companding & SQRT Techniques for M-QAM OFDM systems,” in proc. IEEE International Conference on Emerging Trends in Computing, Communication and Nanotechnology (ICECCN) 2013.
_||_[1] K. D. Choe, S.C. Kim, and S. K. Park, “Pre-Scrambling Method for PAPR Reduction in OFDM Communication Systems”, IEEE Transactions on Consumer Electronics, vol. 50, No. 4, November 2004.
[2] S. Sengar, and P. P. Bhattacharya, “Performance Improvement in OFDM System by PAPR Reduction,” Signal & Image Processing: An International Journal (SIPIJ), vol.3, No.2, April 2012.
[3] M.Chauhan, S.Patel and H.Patel, “Different Techniques to Reduce the PAPR in OFDM System,” International Journal of Engineering Research and Applications (IJERA), vol. 2, no. 3, pp.1292-1294, Jun 2012.
[4] M.Chauhan, A.Chobey, “PAPR Reduction in OFDM system Using Tone Reservation Technique,” International Journal of Computer Technology and Electronics Engineering (IJCTEE), vol. 2, no. 4, August 2012.
[5] D.Xie, S.Yang, L. Qi and X. Mu, “PAPR Reduction Of FrFT-Based MB-OFDM Ultra Wide Band Signals”, in proc. 4th International Conference on Wireless Communications, Networking and Mobile Computing, Oct 2008.
[6] C. Rezgui, S. Jarboui, K. Grayaa, “A PAPR reduction technique based on Golay sequences and Fractional Fourier Transform for OFDM Systems”, Computing, in proc. Communications and Applications Conference, jan 2012.
[7] P. Elavarasan, Dr.G. Nagarajan and A.Narayanan, “P APR Reduction in MIMO-OFDM Systems using Joint Channel Estimationand Precoding”, in proc. IEEE International Conference on Advanced Communication Control and Computing Technologies (ICACCCT), 2012.
[8] S.B. Slimane, “Reducing the Peak-to-Average Power Ratio of OFDM Signals Through Precoding,” IEEE Transactions on Vehicular Technologyvol, Vol. 56, No. 2, March 2007.
[9] C.Y. Hsu and H.C. Liao, “PAPR Reduction Using the Combination of Precoding and Mu-Law Companding Techniques for OFDM Systems,” in proc. ICSP, Oct 2012.
[10] X. Wang, T.T. Tjhung and C.S. Ng, “Reduction of peak-to-averagepower ratio of OFDM system using a companding technique,” IEEETrans. Broadcast, vol. 45, no. 3, pp. 303-307, Sept. 1999.
[11] Y.Jiang, “New companding Transform for PAPR Reduction inOFDM,” IEEE Communications Letters, vol. 14, no. 4, pp. 282–284, April 2010.
[12] Md. I. Abdullah, Md. Z Mahmud, Md. S. Hossain and Md.N. Islam, “Comparative Study of PAPR Reduction Techniques in OFDM,” ARPN Journal of Systems and Software, vol. 1, NO. 8, November 2011.
[13] P. Elavarasan, Dr. G.Nagarajan and A Narayanan, “PAPR Reduction in MIMO-OFDM Systems using Joint Channel Estimation and Precoding,” International Conference on Advanced Communication Control and Computing Technologies (ICACCCT),vol. 3, no. 1, January 2012.
[14] Z. Wang, “Combined DCT and Companding for PAPR Reduction in OFDM Signals,” Journal of Signal and Information Processing, vol. 2, pp. 100-104, 2011.
[15] T. Jiang, Y. Yang and Y.H. Song, “Companding Technique for PAPR Reduction in OFDM Systems Based on An Exponential Function”, in proc. IEEE GLOBECOM, 2005.
[16] T. Deepa, R. Kumar, “Performance Analysis of μ-law Companding & SQRT Techniques for M-QAM OFDM systems,” in proc. IEEE International Conference on Emerging Trends in Computing, Communication and Nanotechnology (ICECCN) 2013.
