In this paper, a Turbo aided Cyclic Prefix (CP) reconstruction scheme, termed Turbo- CPR, is proposed for Single-Carrier systems with Frequency-Domain Equalization (SC-FDE) that employ insufficient CP in the transmitt...In this paper, a Turbo aided Cyclic Prefix (CP) reconstruction scheme, termed Turbo- CPR, is proposed for Single-Carrier systems with Frequency-Domain Equalization (SC-FDE) that employ insufficient CP in the transmitter. In Turbo-CPR, the decoder output is incorporated in the process of equalization, i.e. Turbo equalizer is employed. It is shown in the simulation results that Turbo-CPR not only recovers the performance loss due to insufficiency of CP, but also provides extra gains over the lower bound of performance for conventional CP reconstruction schemes.展开更多
A Jointly Gaussian (JG) equalizer is derived for turbo equalization based on an augmented real matrix representation of channel model and a Gaussian approximation of the received symbol sequence. Using matrix inversio...A Jointly Gaussian (JG) equalizer is derived for turbo equalization based on an augmented real matrix representation of channel model and a Gaussian approximation of the received symbol sequence. Using matrix inversion lemma and Cholesky decomposition, a lowcomplexity implementation of JG equalizer is also presented. The simulation results and complexity comparison confirm that turbo equalization with JG equalizer has a better performance and a lower complexity than the existing turbo equalization with linear minimum mean squared error equalizer.展开更多
In this paper,we propose a novel iterative scheme for exploiting transmit diversity using parallel independent Inter-Symbol Interference (ISI) channels. In this adaptive iterative scheme,we use EXtrinsic Information T...In this paper,we propose a novel iterative scheme for exploiting transmit diversity using parallel independent Inter-Symbol Interference (ISI) channels. In this adaptive iterative scheme,we use EXtrinsic Information Transfer (EXIT) chart tool to choose appropriate iterative method from Itera-tive Combining (IC),used as parallel concatenation turbo-like scheme,and Turbo Equalization (TE),used as serial concatenation turbo-like scheme. It is show that the proposed iterative scheme provides excellent performance both analytically and through simulations without any compute complexity increase comparable to IC.展开更多
Reasonable bit error rate performance requires perfect channel state information （CSI） in traditional turbo equalization （TE）, which is hard to obtain in practice. Soft and hard iterative algorithms have been deve...Reasonable bit error rate performance requires perfect channel state information （CSI） in traditional turbo equalization （TE）, which is hard to obtain in practice. Soft and hard iterative algorithms have been developed to address the channel estimation problem with the performance of the soft iteratwe channel estimate based on the recursive least square algorithm. This paper presents an analysis of the performance of hard iterative channel estimation （HICE） based on the least mean square algorithm. The analysis uses a cost function with the hard decision on the TE output. An iterative channel correction （ICC） algorithm based on the gradient descent algorithm is used to iteratively minimize the cost function. The simulation results agree with the theoretical lower bound for the mean square error （MSE） of the estimated channels. Simulations show that, given an imperfect CSI with an MSE below the upper bound, the linear minimum mean squared error TE （LMMSE-TE） using the ICC has only small performance degradation compared to that with a perfect CSI, while the traditional LMMSE-TE suffers from severe error floor effect even with more iterations.展开更多
文摘In this paper, a Turbo aided Cyclic Prefix (CP) reconstruction scheme, termed Turbo- CPR, is proposed for Single-Carrier systems with Frequency-Domain Equalization (SC-FDE) that employ insufficient CP in the transmitter. In Turbo-CPR, the decoder output is incorporated in the process of equalization, i.e. Turbo equalizer is employed. It is shown in the simulation results that Turbo-CPR not only recovers the performance loss due to insufficiency of CP, but also provides extra gains over the lower bound of performance for conventional CP reconstruction schemes.
文摘A Jointly Gaussian (JG) equalizer is derived for turbo equalization based on an augmented real matrix representation of channel model and a Gaussian approximation of the received symbol sequence. Using matrix inversion lemma and Cholesky decomposition, a lowcomplexity implementation of JG equalizer is also presented. The simulation results and complexity comparison confirm that turbo equalization with JG equalizer has a better performance and a lower complexity than the existing turbo equalization with linear minimum mean squared error equalizer.
基金Supported by the National Natural Science Foundation of China (No.60372030)China Ministry of Education Foundation for Visiting Scholar (No.[2003]406)Key Project of Provincial Scientific Foundation of Shandong (No.Z2003G02).
文摘In this paper,we propose a novel iterative scheme for exploiting transmit diversity using parallel independent Inter-Symbol Interference (ISI) channels. In this adaptive iterative scheme,we use EXtrinsic Information Transfer (EXIT) chart tool to choose appropriate iterative method from Itera-tive Combining (IC),used as parallel concatenation turbo-like scheme,and Turbo Equalization (TE),used as serial concatenation turbo-like scheme. It is show that the proposed iterative scheme provides excellent performance both analytically and through simulations without any compute complexity increase comparable to IC.
基金Supported by the National High-Tech Research and Development (863) Program of China
文摘Reasonable bit error rate performance requires perfect channel state information （CSI） in traditional turbo equalization （TE）, which is hard to obtain in practice. Soft and hard iterative algorithms have been developed to address the channel estimation problem with the performance of the soft iteratwe channel estimate based on the recursive least square algorithm. This paper presents an analysis of the performance of hard iterative channel estimation （HICE） based on the least mean square algorithm. The analysis uses a cost function with the hard decision on the TE output. An iterative channel correction （ICC） algorithm based on the gradient descent algorithm is used to iteratively minimize the cost function. The simulation results agree with the theoretical lower bound for the mean square error （MSE） of the estimated channels. Simulations show that, given an imperfect CSI with an MSE below the upper bound, the linear minimum mean squared error TE （LMMSE-TE） using the ICC has only small performance degradation compared to that with a perfect CSI, while the traditional LMMSE-TE suffers from severe error floor effect even with more iterations.
