Abstract
Orthogonal frequency division multiplexing (OFDM) systems have inherent symmetric properties, such as coding and decoding, constellation mapping and demapping, inverse fast Fourier transform (IFFT) and fast Fourier transform (FFT) operations corresponding to multi-carrier modulation and demodulation, and channel estimation is a necessary module to resist channel fading in the OFDM system. However, the noise in the channel will significantly affect the accuracy of channel estimation, which further affects the recovery quality of the final received signals. Therefore, this paper proposes an efficient noise suppression channel estimation method for OFDM systems based on adaptive weighted averaging. The basic idea of the proposed method is averaging the last few channel coefficients obtained from coarse estimation to suppress the noise effect, while the average frame number is adaptively adjusted by combining Doppler spread and signal-to-noise ratio (SNR) information. Meanwhile, to better combat the negative effect brought by Doppler spread and inter-carrier interference (ICI), the proposed method introduces a weighting factor to correct the weighted value of each frame in the averaging process. Simulation results show that the proposed channel estimation method is effective and provides better performance compared with other conventional channel estimation methods.
Highlights
Orthogonal frequency division multiplexing (OFDM) technology is widely used in modern communication systems for its superior performance and high spectral efficiency [1,2]
The simulation experiments are presented to demonstrate the performance of the proposed adaptive weighted averaging (AWA)-based noise suppression channel estimation method
The multipath channel models are China digital television (DTV) Test 1st (CDT1), CDT6, Brazil A, Brazil B, and Brazil D, where CDT1 and CDT6 channels are from the field tests for digital terrestrial television broadcasting (DTTB) in China and Brazil A, Brazil B, and Brazil D [19] channels are from the field tests for DTTB in Brazil [33]
Summary
Orthogonal frequency division multiplexing (OFDM) technology is widely used in modern communication systems for its superior performance and high spectral efficiency [1,2]. Blind and semi-blind estimation perform channel estimation with non-pilot and few pilots, respectively, and have higher spectral efficiency These two methods suffer from high computational complexity and are not preferred in practice. Comb-type pilot-based channel estimation is used in OFDM systems since comb-type pilot is more robust to a time-varying channel with low to high Doppler spread. To suppress the noise effect in the channel and obtain more accurate channel estimation results, this paper proposes an adaptive weighted averaging (AWA)-based noise suppression channel estimation method. The essence of the proposed method is to average the last few channel coefficients obtained from coarse estimation to suppress the noise effect, while the average frame number is adaptively adjusted by combining Doppler spread and signal-to-noise ratio (SNR) information.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
