Weighted ESAE channel estimation method for OFDM systems
ABSTRACT OFDM (orthogonal frequency division multiplexing) is a promising technique for achieving the high-bit-rates required by a wireless multimedia service over the time-dispersive multipath channel. The PSAM (pilot-symbol assisted modulation) technique is a common OFDM system channel estimation method which uses time and frequency correlation of the channel. The ESAE (extended symbol aided estimation) method has more robust features in a fast fading channel, but it has an unstable property in a high-speed environment. The paper proposes a weighted ESAE channel estimation method which is based on the conventional ESAE method. In time and frequency selective channels, this method has a low algorithm complexity and short processing delay, and the BER performance is better than the conventional ESAE and PSAM methods.
- SourceAvailable from: Bert Gyselinckx[show abstract] [hide abstract]
ABSTRACT: Orthogonal frequency-division multiplexing with cyclic prefix enables low-cost frequency-domain mitigation of multipath distortion. However, to determine the equalizer coefficients, knowledge of the channel frequency response is required. While a straightforward approach is to measure the response to a known pilot symbol sequence, existing literature reports a significant performance gain when exploiting the frequency correlation properties of the channel. Expressing this correlation by the finite delay spread, we build a deterministic model parametrized by the channel impulse response and, based on this model, derive the maximum-likelihood channel estimator. In addition to being optimal (up to the modeling error), this estimator receives an elegant time-frequency interpretation. As a result, it has a significantly lower complexity than previously published methods.IEEE Transactions on Communications 03/2003; · 1.75 Impact Factor
Conference Proceeding: DFT-based channel estimation in 2D-pilot-symbol-aided OFDM wireless systems[show abstract] [hide abstract]
ABSTRACT: An efficient channel estimation algorithm for OFDM in wireless applications has been proposed. Two-dimensional pilot-symbol assisted modulation (2D-PSAM) is employed in coherent OFDM for channel estimation and it is based on inserting known symbols spreaded throughout the 2D time-frequency grid. These scattered symbols are employed to perform an estimation of the channel's frequency response. At a first stage, if certain requirements are fulfilled, channel estimation in frequency dimension can be carried out with an efficient DFT-based algorithm, which provides an accurate estimation at time positions where pilot symbols are included. In the second step, linear interpolation is performed in the time direction. This scheme has been proven to be very successful in multicarrier HF communications systemsVehicular Technology Conference, 2001. VTC 2001 Spring. IEEE VTS 53rd; 02/2001
Conference Proceeding: A novel channel estimation method for OFDM in high-speed mobile system[show abstract] [hide abstract]
ABSTRACT: In order to meet the requirements which are considered in an OFDM system under a high-speed mobile environment, lots of techniques have been studied. In mobile communication systems, fading distortion affects the overall performance. Furthermore, the higher the velocity of any mobile system, the more severe the effect of fading is. To solve this problem, in an OFDM system, exact channel estimation can be an important method. We propose a channel estimation method which outperforms conventional methods. The analytical results demonstrate that the proposed system has better performance than the conventional methods such as PSAM and ESAEIndustrial Electronics, 2001. Proceedings. ISIE 2001. IEEE International Symposium on; 02/2001