Abstract
Multiple-input and multiple-output (MIMO) systems formed by multiple transmit and receive antennas can improve performance and increase capacity of wireless communication systems. Diagonal Bell Laboratories Layered Space-Time (D-BLAST) structure offers a low-complexity solution for realizing the attractive capacity of MIMO systems. However, for broadband wireless communications, channel is frequency-selective and orthogonal frequency division multiplexing (OFDM) has to be used with MIMO techniques to reduce system complexity. In this paper, we investigate D-BLAST for MIMO-OFDM systems. We develop a layerwise channel estimation algorithm which is robust to channel variation by exploiting the characteristic of the D-BLAST structure. Further improvement is made by subspace tracking to considerably reduce the error floor. Simulation results show that the layerwise estimators require 1 dB less signal-to-noise ratio (SNR) than the traditional blockwise estimator for a word error rate (WER) of when Doppler frequency is 40 Hz. Among the layerwise estimators, the subspace-tracking estimator provides a 0.8 dB gain for WER with 200 Hz Doppler frequency compared with the DFT-based estimator.
Highlights
Multiple-input and multiple-output (MIMO) systems formed by multiple transmit and receive antennas are under intense research recently for its attractive potential to offer great capacity increase
I=1 for j = 1, . . . , Nr and k = 0, . . . , K − 1, where K is the total number of subcarriers of orthogonal frequency division multiplexing (OFDM), bi[n, k] is the symbol transmitted from the ith transmit antenna at the kth subcarrier of the nth block, Hij[n, k] is the channel’s frequency response at the kth subcarrier of the nth block corresponding to the ith transmit and the jth receive antenna, and wj[n, k] is additive Gaussian noise that is assumed to be independent and identically distributed (i.i.d.) with zero-mean and variance ρ
We evaluate the performance of different decision-directed channel estimation algorithms for DBLAST OFDM by computer simulation
Summary
Multiple-input and multiple-output (MIMO) systems formed by multiple transmit and receive antennas are under intense research recently for its attractive potential to offer great capacity increase. Space-time coding, proposed in [1], performs channel coding across the space and time to exploit the spatial diversity offered by MIMO systems to increase system capacity. To reduce the complexity of space-time based MIMO systems, diagonal Bell Laboratories layered space-time (D-BLAST) architecture has been proposed in [2]. We investigate D-BLAST OFDM systems and address the channel estimation problem. DFT-based least-square (LS) channel estimation for MIMO-OFDM systems and simplified estimation algorithm using parallel interference cancellation have been addressed in [4, 5], respectively. To reduce the error floor of DFT-based algorithm and increase estimation accuracy, more taps have.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
