Robust characterization of wireless channel using matching pursuit technique

• Main Author: Chen, Lei
• Published: University of Edinburgh 2009
• Subjects: 621.382
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.642785

In this thesis, we propose to use matching pursuit (MP) to specify the basis expansion model (BEM) coefficients for fast time-varying flat-fading channels. Further, sequential matching pursuit (SMP) is proposed by removing the selection process of MP so that the computational complexity is significantly reduced. Via computer-based simulations, it is shown that MP and SMP are able to provide a robust channel estimate when using more basis functions than necessary. A mathematical expression of eth SMP performance is approximately established, and can be used to represent the MP performance to a certain extent. Besides, MP and SMP even perform well without the information of signal-to-noise ratio (SNR). The applications of MP and SMP in flat-fading channels are extended to an orthogonal frequency division multiplexing (OFDM) system. For OFDM, there are channel variations in the time and frequency directions. Firstly, flat-fading subcarrier channels in OFDM are represented by the BEM in the time direction. The studies of MP and SMP for flat-fading channels are suggested to directly apply to the subchannels in OFDM. Secondly, a non-sample-spaced channel with a continuous power delay profile is described by the BEM along the frequency direction in OFDM. Both MP and SMP are also employed to determine the BEM coefficients in such an occasion. Finally, a cascading channel estimator formed by combining the above two channel estimation schemes in the time and frequency directions is studied. The effectiveness of these channel characterization schemes is verified by the simulation study. The robustness of MP and SMP, when the BEM uses a larger model order than the optimal one, is confirmed by the simulation result.