OFDM Channel Estimation Enhancement using Null Subcarriers
Main Article Content
Abstract
Orthogonal frequency division multiplexing (OFDM) is one of the popular techniques for high data rates nowadays. However, the channel transfer function estimation for OFDM based systems is essential, to increase the bit rate with low bit error rate (BER) degradation. Numerous algorithms are provided in the literature such as the pilot assisted channel estimation methods. This paper suggests to making use of the null subcarriers, such as the cyclic prefix interval, to make more occupation of the pilot subcarriers. Least squares estimator has been employed to estimate the channel frequency response. However, simulation results, using MATLAB programming, show that the BER performance has been improved, where the required signal to noise ratio (SNR) has been reduced by approximately 4dB, for different baseband mapping.
Metrics
Article Details

This work is licensed under a Creative Commons Attribution 4.0 International License.
THIS IS AN OPEN ACCESS ARTICLE UNDER THE CC BY LICENSE http://creativecommons.org/licenses/by/4.0/
Plaudit
References
IEEE-Std-802.16-2009, IEEE Standard for Local and metropolitan area networks Part 16: Air Interface for Broadband Wireless Access Systems Amendment 3: Advanced Air Interface. IEEE Std 802.16m-2011(Amendment to IEEE Std 802.16-2009): 1-1112, 2011.
MadanPande GP. Optimal resource allocation scheme for LTE-A systems with carrier aggregation. 2014 IEEE International Conference on Advanced Networks and Telecommuncations Systems (ANTS) 2014; New Delhi, India: pp. 1-6. DOI: https://doi.org/10.1109/ANTS.2014.7057230
Athaudage CRN, Jayalath ADS. Enhanced MMSE channel estimation using timing error statistics for wireless OFDM systems. IEEE Transactions on Broadcasting 2004; 50 (4): 369-376. DOI: https://doi.org/10.1109/TBC.2004.837861
Beek JJVD, Edfors O, Sandell M, Wilson SK, Borjesson PO. On channel estimation in OFDM systems. IEEE 45th Vehicular Technology Conference 1995 July 25-28; IEEE Xplore Press, Chicam, Illinois, USA: pp. 815-819.
Meng-Han H, Che-Ho W. Channel estimation for OFDM systems based on comb-type pilot arrangement in frequency selective fading channels. IEEE Transactions on Consumer Electronics 1998; DOI: https://doi.org/10.1109/30.663750
(1): 217-225.
Die H, Luxi Y. Time-varying channel estimation based on pilot tones in OFDM systems. The 2003 International Conference on Neural Networks and Signal Processing 2003 December 14-17; IEEE Xplore Press, Nanjing, China: pp. 700-703. DOI: https://doi.org/10.1109/ICNNSP.2003.1279371
Ye L. Pilot-symbol-aided channel estimation for OFDM in wireless systems. IEEE Transactions on Vehicular Technology 2000 49 (4): 1207-1215. DOI: https://doi.org/10.1109/25.875230
Ozdemir MK, Arslan H. Channel estimation for wireless ofdm systems. IEEE Communications Surveys & Tutorials 2007; 9 (2): 18-48. DOI: https://doi.org/10.1109/COMST.2007.382406
Liu YZ, Tan H., Cimini LJ, Li GY. Channel estimation for OFDM. IEEE Communications Surveys & Tutorials 2014; 16 (4): 1891-1908. DOI: https://doi.org/10.1109/COMST.2014.2320074
Coleri S, Ergen M, Puri A, Bahai A. Channel estimation techniques based on pilot arrangement in OFDM systems. IEEE Transactions on Broadcasting 2002; 48 (3): 223-229. DOI: https://doi.org/10.1109/TBC.2002.804034
Bingham JAC. Multicarrier modulation for data transmission: an idea whose time has come. IEEE Communications Magazine 1990; 28 (5): 5-14. DOI: https://doi.org/10.1109/35.54342
Amo CPD, Garcia MJFG. Suppression of cyclic prefix in down-link LTE like systems to increase capacity. IEEE 77th Vehicular Technology Conference (VTC Spring) 2013: pp. 1-5.
Amo CPD, García MJFG. Iterative joint estimation procedure for channel and frequency offset in multi-antenna OFDM systems with an insufficient cyclic prefix. IEEE Transactions on Vehicular Technology 2013; 62 (8): 3653-3662. DOI: https://doi.org/10.1109/TVT.2013.2260571
Li B, Xu W, Li S, Lin J. Energy efficient power allocation in OFDM-based CRNS with cyclic prefix power transfer. IEEE 81st Vehicular Technology Conference 2015: pp. 1-5. DOI: https://doi.org/10.1109/VTCSpring.2015.7145810
Bin S. An energy efficient transmission scheme for OFDM systems in LTE. China Communications 2014; 11 (3): 13-18. DOI: https://doi.org/10.1109/CC.2014.6825254
Li Y, Cimini LJ, Sollenberger NR. Robust channel estimation for OFDM systems with rapid dispersive fading channels. IEEE Transactions on Communications 1998; 46 (7): 902-915. DOI: https://doi.org/10.1109/26.701317
Baoguo Y, Letaief KB, Cheng RS, Zhigang C. Channel estimation for OFDM transmission in multipath fading channels based on parametric channel modeling. IEEE Transactions on Communications 2001; 49 (3): 467-479. DOI: https://doi.org/10.1109/26.911454
Ping Z, Yong W, Xiaofeng T, Xiaodong X, Qimei C, Qiang W. Key technology and trial system for Gbps wireless transmission. China Communications 2010; 7 (1): 99-103.