Wan, Ping2011-07-182011-07-1820112011-07-18http://hdl.handle.net/1828/3413The increasing demand for high data rate transmission over broadband radio channels has imposed significant challenges in wireless communications. Accurate channel estimation has a major impact on the whole system performance. Specifically, reliable estimate of the channel state information (CSI) is more challenging for orthogonal frequency division multiplexing (OFDM) systems in doubly selective fading channels than for the slower fading channels over which OFDM has been deployed traditionally. With the help of a basis expansion model (BEM), a novel multivariate autoregressive (AR) process is developed to model the time evolution of the fast fading channel. Relying on pilot symbol aided modulation (PSAM), a novel Kalman smoothing algorithm based on a second-order dynamic model is exploited, where the mean square error (MSE) of the channel estimator is near to that of the optimal Wiener filter. To further improve the performance of channel estimation, a novel low-complexity iterative joint channel estimation and symbol detection procedure is developed for fast fading channels with a small number of pilots and low pilot power to achieve the bit error rate (BER) performance close to when the CSI is known perfectly. The new channel estimation symbol detection technique is robust to variations of the radio channel from the design values and applicable to multiple modulation and coding types. By use of the extrinsic information transfer (EXIT) chart, we investigate the convergence behavior of the new algorithm and analyze the modulation, pilot density, and error correction code selection for good system performance for a given power level. The algorithms developed in this thesis improve the performance of the whole system requiring only low ratios of pilot to data for excellent performance in fast fading channels.enfast fading channelsmultivariate autoregressive processorthogonal frequency-division multiplexing (OFDM)channel estimation techniquesjoint channel estimation and symbol detectionextrinsic information transfer (EXIT) chartThesisAvailable to the World Wide WebPing Wan and Michael McGuire and Xiaodai Dong, Near Optimal Channel Estimation for OFDM in Fast Fading Channels, in Proc IEEE Wireless Communications and Networking Conference (WCNC), pp. 1-6, Apr. 2010Ping Wan and Michael McGuire, Channel Estimation in Fast Fading Channels, in Proc IEEE ChinaCom, pp. 647-651, Aug. 2008Ping Wan and Michael McGuire, An Iterative Decision Feedback Algorithm using the Cholesky Update for OFDM with Fast Fading, in Proc IEEE Pacific Rim Conference (PCRIM), pp. 522-525, Aug. 2007Michael McGuire and Ping Wan, Analysis of joint channel estimation and equalization using a {K}alman filter'', in Proc IEEE Canadian Conference on Electrical and Computer Engineering (CCECE), pp. 912-915, Jan. 2006Ping Wan and Michael McGuire and Xiaodai Dong, Near Optimal Channel Estimation for OFDM in Fast Fading Channels, accepted by IEEE Transactions on Vehicle Technology