Compressive Sensing-Based Adaptive Sparse Multipath Channel Estimation

Author(s):  
Beiyi Liu ◽  
◽  
Guan Gui ◽  
Shin-ya Matsushita ◽  
Li Xu ◽  
...  

Sparse multipath channel estimation has recently attracted significant attention due to the sparsity of the channel in broadband wireless communication. Many algorithms have been proposed for sparse multipath channel estimation. Among them, the least mean square (LMS) algorithm, based on adaptive filter, has attracted much attention due to its low complexity and high robustness. However, LMS is usually degraded by the long training signal, which needs large storage space. This paper proposes an improved method that transmits a circulating, short training signal, samples the received signal at a lower rate, and utilizes LMS with ℓ0-norm (ℓ0-LMS) to estimate the sparse multipath channel. This method can achieve high robustness in additive white Gaussian noise (AWGN), and reduce the sampling rate while needing small storage space for the training signal. Numerical simulations are provided to evaluate the performance of the proposed method.

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Meher Krishna Patel ◽  
Stevan M. Berber ◽  
Kevin W. Sowerby

This paper presents the antijamming performance of adaptive multiuser DS-CDMA system using maximal ratio combining technique in slow switching pulse noise jammer. Complex flat fading channel coefficients are assumed to be unknown at the receiver. Pilot symbols are used to estimate the fading coefficients using least mean square (LMS) algorithm, and effect of imperfect channel estimation on bit error rate (BER) is studied. Under the perfect synchronization conditions, probability of error in closed form is derived.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Meher Krishna Patel ◽  
Stevan M. Berber ◽  
Kevin W. Sowerby

This paper presents an adaptive multiuser transceiver scheme for DS-CDMA systems in which pilot symbols are added to users’ data to estimate complex channel fading coefficients. The performance of receiver antenna diversity with maximal ratio combining (MRC) technique is analyzed for imperfect channel estimation in flat fading environments. The complex fading coefficients are estimated using least mean square (LMS) algorithm and these coefficients are utilized by the maximal ratio combiner for generating the decision variable. Probability of error in closed form is derived. Further, the effect of pilot signal power on bit error rate (BER) and BER performance of multiplexed pilot and data signal transmission scenario are investigated. We have compared the performance of added and multiplexed pilot-data systems and concluded the advantages of both systems. The proposed CDMA technique uses the chaotic sequence as spreading sequence. Assuming proper synchronization, the computer simulation results demonstrate the better bit error rate performance in the presence of channel estimator in the chaotic based CDMA system and the receiver antenna diversity technique further improves the performance of the proposed system. Also, no channel estimator is required if there is no phase distortion to the transmitted signal.


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