Space-time Block Code Multiple-input Multiple-output Research Articles

Fast Symbol Detection for Massive G-STBC MIMO Systems

In this paper, a group-based fast symbol detection scheme is proposed for massive Group-wise Space–Time Block Code Multiple-Input Multiple-Output systems. The proposed scheme first chooses a number G, (e.g. $$G=4,6,8$$ ) as the size of each group and then conducts the Minimum Mean Square Error (MMSE) detectors to facilitate symbol detection group by group. In particular, instead of directly using huge computational complexity to compute the MMSE detectors, the proposed scheme recursively finds the corresponding assistant matrices to determine the groups and calculate the MMSE detectors. As a result, the transmitted symbols can be recursively estimated group by group. Finally, simulation results and complexity analysis show the proposed scheme performs very close to the existing methods, while using lower computational complexity.

Analysis of the Alamouti STBC MIMO System With Spatial Division Multiplexing Over the Rayleigh Fading Channel

The Alamouti space-time block coding (STBC) multiple input multiple output (MIMO) system with spatial division multiplexing (SDM) is different from the pure SDM MIMO system in transmitting groups of Alamouti STBC symbols. Because of the Alamouti STBC, the zero-forcing with successive interference cancellation (ZF-SIC) detector for this MIMO system also detects one group of Alamouti STBC symbols in its one iteration. Previous analytical studies on this MIMO system were concentrated on the scenario of only four transmit antennas and did not take full advantage of the group-wise properties of the equivalent channel matrix due to Alamouti STBC. To deliver indepth analysis of this MIMO system with arbitrary number of transmit antennas, the ZF-SIC detection of the groups of Alamouti STBC symbols over the independent identically distributed Rayleigh fading channel is analyzed. Exact average block error probability of detecting all groups of Alamotui STBC symbols and its high signal-to-noise ratio (SNR) approximation are computed. Also, exact average group error probability of detecting each group of Alamotui STBC symbols and its high SNR approximation are computed. These analytical results are shown to agree with the simulation results.

Precoding design for STBC‐MIMO system with imperfect feedback in spatially correlated Rayleigh channel

By minimising the pairwise error probability (PEP) bound subject to the fixed power constraint, a suboptimal precoding scheme for space–time block-coded multiple-input–multiple-output (STBC-MIMO) systems with mean and covariance feedback in spatially correlated Rayleigh fading channels is developed, which can include the mean-feedback only and covariance-feedback only as its special cases. This scheme can achieve performances close to the existing optimal scheme while being more computationally efficient. The simulation results show that the proposed scheme can provide better performances than the conventional equal power scheme, and achieve almost the same performances as the existing optimal scheme.

Block-Wise QR-Decomposition for the Layered and Hybrid Alamouti STBC MIMO Systems: Algorithms and Hardware Architectures

Unlike the channel matrix in the spatial division multiplexing (SDM) multiple-input multiple-output (MIMO) communication system, the equivalent channel matrix in the layered Alamouti space-time block coding (STBC) MIMO system comprised 2-by-2 Alamouti sub-blocks. One novel property, found by Sayed about the QR-decomposition (QRD) of this equivalent channel matrix is that the produced Q- and R-matrices are also matrices with Alamouti sub-blocks. Taking advantage of this property, we propose a new block-wise complex Givens rotation (BCGR) based algorithm and a triangular systolic array (TSA) to compute the QRD of the equivalent channel matrix in an Alamouti block by block manner. Implementation results reveal that our new TSA can compute QRDs of 4-by-4 equivalent channel matrices faster than any architecture that has been developed for the SDM MIMO system. This property of fast QRD makes our TSA very attractive for the layered Alamouti STBC MIMO system combined with the orthogonal frequency division multiplexing. Our new BCGR based approach can also be applied to the hybrid Alamouti STBC MIMO system, which is also a system with equivalent channel matrix consisting of Alamouti sub-blocks.

PAPR Reduction in STBC MIMO OFDM System using AMS and PTS Schemes

data rates and reliability are the two key factors required to support emerging multimedia applications and new communications technologies. The two techniques used in high data rate transmission are orthogonal frequency division multiplexing (OFDM) and multiple-input multiple- output (MIMO) scheme. The OFDM is used to mitigate the problem of inter symbol interference (ISI) and provides good protection against co-channel interference and noise. MIMO system helps to reduce fading and can be used for decreasing bit error rate that is spatial diversity or to increase the data rate that is spatial multiplexing. The combination of MIMO and OFDM is MIMO OFDM system. MIMO-OFDM system converts frequency selective MIMO channel into multiple parallel flat fading channels. One of the major drawbacks of in MIMO-OFDM systems is that the transmitted signal exhibits a high PAPR when the input sequences are correlated. In this paper, AMS and PTS schemes have been used to reduce peak to average power ratio (PAPR) in multiple input multiple output orthogonal frequency division multiplexing (MIMO OFDM) system with Alamouti's space time block coding (STBC). The AMS scheme reduces the computational complexity and when AMS scheme is used with quadrature amplitude modulation (QAM). Simulation and results show that the AMS scheme reduces PAPR more efficiently than the PTS scheme.