Improved Algorithm Based on the DFT Transform Channel Estimation and Threshold Filtering

Abstract:

In channel estimation, the complexity of the DFT-based channel estimation algorithm is lower than the MMSE algorithm, and the DFT-based algorithm performs better than the LS algorithm. However, due to that the traditional algorithms simply considered all the samples to be useful channel impulse response, ignoried the effect of noise. Therefore, the algorithm could be improved. This paper presents an improved algorithm based on twice noise estimation theory. The algorithm uses the sequence of points other than the cyclic prefix length to estimate the noise variance firstly, and then use the estimated noise variance to distinguish the noise samples within the cyclic prefix length. The computation of the new noise variance and noise mean through the new noise points as a threshold filters the impulse response of the channel in time domain and eliminates the impact of noise on the system further. The simulation result shows that the improved algorithm performs better than the traditional algorithm.

• Periodical: Applied Mechanics and Materials (Volume 391)
• Pages: 536-539
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.391.536
• Online since: September 2013
• Authors: Chao Ma, Chun Xian Xiao, Jiang Zhu
• Keywords: Channel Estimation, DFT, Orthogonal Frequency Division Multiplexing (OFDM), Quadratic Noise Estimation

References

[1] Kang Y, Kim K, Park H. Efficient DFT-based channel estimation for OFDM systems on multipath channels [J]. IEEE Transactions on Institution of Engineering and Technology Communications, 2007, 1(2): 197-202.

DOI: 10.1049/iet-com:20050337

[2] Oliver J, Aravind R, Prabhu K.M.M. Sparse channel estimation in OFDM systems by threshold-based pruning [J]. IEEE Transactions on Electronic Letter, 2008, 44(13): 830-832.

DOI: 10.1049/el:20081089

[3] Rosati S, Corazza Giovanni E, Alessandro V. OFDM Channel Estimation with Optimal Threshold Based Selection of CIR Samples[C] / Proc. Of Globe Telecommunications Conference, IEEE Press, 2009: 1-7.

DOI: 10.1109/glocom.2009.5425939

[4] Wang X Q, Wang J T, Wang Z C. Improved DFT-Based Channel Estimation for OFDM Systems over Multipath Channels[C]/ Proc. Of International Wireless Communications and Mobile Computing Conference, IEEE Press, 2010, 585-590.

DOI: 10.1145/1815396.1815532

[5] Lee Y S, Shin H C, Kim H N. Channel Estimation Based on a Time-Domain Threshold for OFDM Systems [J]. IEEE Transactions on Broadcasting, 2009, 55(3): 656-662.

DOI: 10.1109/tbc.2009.2027575