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Channel Impulse Response Length and Noise Variance Estimation for OFDM Systems with Adaptive Guard Interval
EURASIP Journal on Wireless Communications and Networking volume 2007, Article number: 024342 (2007)
A new algorithm estimating channel impulse response (CIR) length and noise variance for orthogonal frequency-division multiplexing (OFDM) systems with adaptive guard interval (GI) length is proposed. To estimate the CIR length and the noise variance, the different statistical characteristics of the additive noise and the mobile radio channels are exploited. This difference is due to the fact that the variance of the channel coefficients depends on the position within the CIR, whereas the noise variance of each estimated channel tap is equal. Moreover, the channel can vary rapidly, but its length changes more slowly than its coefficients. An auxiliary function is established to distinguish these characteristics. The CIR length and the noise variance are estimated by varying the parameters of this function. The proposed method provides reliable information of the estimated CIR length and the noise variance even at signal-to-noise ratio (SNR) of 0 dB. This information can be applied to an OFDM system with adaptive GI length, where the length of the GI is adapted to the current length of the CIR. The length of the GI can therefore be optimized. Consequently, the spectral efficiency of the system is increased.
Bottomley GE, Chen J-C, Koilpillai D: System and methods for selecting an appropriate detection technique in a radiocommunication system. US patent 6333953B1, December 2001
Hudson JE: Communication system and methods of estimating channel impulse responses therein. US patent 0043887 A1, March 2003
Larsson EG, Liu G, Li J, Giannakis GB: Joint symbol timing and channel estimation for OFDM based WLANs. IEEE Communications Letters 2001,5(8):325-327. 10.1109/4234.940980
Chen J-H, Lee Y: Joint synchronization, channel length estimation, and channel estimation for the maximum likelihood sequence estimator for high speed wireless communications. Proceedings of the 56th IEEE Vehicular Technology Conference (VTC '02), September 2002, Vancouver, BC, Canada 3: 1535-1539.
Moghaddam PP, Amindavar H, Kirlin RL: A new time-delay estimation in multipath. IEEE Transactions on Signal Processing 2003,51(5):1129-1142. 10.1109/TSP.2003.810290
Zhao Y, Huang A: A novel channel estimation method for OFDM mobile communication systems based on pilot signals and transform-domain processing. Proceedings of the 47th IEEE Vehicular Technology Conference (VTC '97), May 1997, Phoenix, Ariz, USA 3: 2089-2093.
Akaike H: A new look at the statistical model identification. IEEE Transactions on Automatic Control 1974,19(6):716-723. 10.1109/TAC.1974.1100705
Höher P: TCM on frequency-selective land-mobile fading channels. Proceedings of the 5th Tirrenia International Workshop on Digital Communications, September 1991, Tirrenia, Italy 317-328.
Yeh C-S, Lin Y: Channel estimation using pilot tones in OFDM systems. IEEE Transactions on Broadcasting 1999,45(4):400-409. 10.1109/11.825535
Medbo J, Schramm P: Channel Model for HiperLAN/2 in Different Indoor Scenarios . ETSIEPBRAN3ERI085B, March 199
ETSI Technical Specification TS 101 475 V1.1.1 (2000-04) HIPERLAN Type 2; Physical (PHY) layer. 200
Papoulis A: Probability. 3rd edition. McGraw-Hill, New York, NY, USA; 1991.
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Nguyen, V., Kuchenbecker, H., Haas, H. et al. Channel Impulse Response Length and Noise Variance Estimation for OFDM Systems with Adaptive Guard Interval. J Wireless Com Network 2007, 024342 (2007). https://doi.org/10.1155/2007/24342
- Estimate Channel
- Noise Variance
- Spectral Efficiency
- Channel Impulse Response
- Mobile Radio