Minh-Tuan Le

Low-complexity maximum-likelihood decoder for four-transmit-antenna quasi-orthogonal space-time block code

This letter proposes a very low-complexity maximum-likelihood (ML) detection algorithm based on QR decomposition for the quasi-orthogonal space-time block code (QSTBC) with four transmit antennas, called the LC-ML decoder. The proposed algorithm enables the QSTBC to achieve ML performance with significant reduction in computational load for any high-level modulation scheme.

Low complexity MMSE-QRD-based ML decoder for quasi-orthogonal STBC scheme in MIMO wireless communications systems with four-transmit antennas

This work proposes a MMSE-QR decomposition-based (MMSE-QRD) low-complexity maximum-likelihood (ML) decoders for quasi-orthogonal space-time block code (QOSTBC) with 4 transmit antennas, denoted as MMSE-QRD LCML decoder. By stacking received symbols from different received symbol period together and applying QR decomposition on extended channel matrix (D. Wubben et al., 2001) resulting special format of matrix R, the proposed decoders is able to reduce complexity by decouple decoding as H. Jafarkhani (2001). In addition, by using the same principle of Minh-Tuan Le et al. (2005) to jointly detect signals, the MMSE-QRD LCML decoder is able to not only significantly reduce the computational load but also obtain ML performance

Efficient Algorithm for Blind Detection of Orthogonal Space-Time Block Codes

This letter proposes an efficient decoder for signal detection in orthogonal space-time block coded systems employing phase-shift keying modulation without channel state information at the receiver. The proposed decoder consists of a sphere decoder and a QRD-based decoder. Simulation results show that the proposed decoder enables the system to trade off performance improvement against complexity

Low Complexity Maximum-likelihood Decoder for VBLAST-STBC scheme in MIMO Wireless Communication Systems

In this work, we propose a low-complexity maximum-likelihood decoding approach based on QR decomposition (QRD) for signal detection in VBLAST-STBC systems, which employ less receive antennas than transmit antennas. With the example illustration of (6,3) system using rate 3/4 STBC for three transmit antennas, computer simulations are implemented to verify the performance and complexity of the proposed decoder

Efficiency zero-forcing detectors based on group detection for massive MIMO systems

In this paper, we propose efficient Zero-Forcing (ZF) Detectors based on the a Group Detection (GD) approach in order to reduce the computational cost of the conventional linear detectors when they are adopted in Massive MIMO systems. Using the GD, we first divide a Massive MIMO system into two MIMO ones with smaller dimensions. Then, we apply the conventional ZF detector to the sub-systems to recover the signals. The resulting detector is called ZF-GD. In order to further improve the But Error Rate (BER) performance of the receiver, we propose the second detector, called ZF-IGD, by applying the conventional ZF detector to the sub-systems in an iterative manner. Both analytical and simulation results are provided to illustrate the performance and complexity of the proposed detectors. It is shown that they are suitable for Massive MIMO systems and can be used flexibly depending on the compromise between performance improvement and computational complexity.

Novel Approaches for Performance Enhancement of High Rate-Spatial Modulation System

This paper proposes an enhanced sub-optimal detector for the High Rate-Spatial Modulation (HR- SM) systems presented in [1] by incorporating the ISQRD detector previously proposed in [2] with a new search space. The proposed decoder, called Enhanced ISQRD, achieves not only significant improvement in the bit error rate (BER) performance but also complexity reduction as compared to the ISQRD detector. In addition, we propose a new bit mapping approach that allows the HR-SM system to improve its BER performance. Simulation results and complexity analysis are presented to verify the effectiveness of the proposed approaches in terms of performance improvement and detection complexity reduction when they are applied to the HR-SM systems.

High throughput modified MMSE hardware detector for high-rate spatial modulation systems

A High-rate spatial modulation (HR-SM) transmission scheme was proposed in [1]. Compared to conventional Multiple-Input Multiple-Output (MIMO) systems, HR-SM has better bit-error-rate (BER) performance with trade off of spectral efficiency. In this paper, we propose a hardware architecture of HR-SM detector for 4×4 system using Modified-Minimum Mean Square Error - sorted QR decomposition (MSQRD) algorithm which was proposed in [2]. Implementation result shows that our design achieves higher throughput compared to other implementations in conventional MIMO systems despite the disadvantage of spectral utilization in HR-SM, while still keeps latency low and hardware usage acceptable.

Parameter-Optimized Extended MMSE-DFE based Detection for V-BLAST

In this work, the optimal value of parameter for complexity reduction of an Extended MMSE-DFE based Detection for V-BLAST system is considered. The detection, which is based on the fast sphere decoder for Phase-Shift Keying (PSK) signals in uncoded V-BLAST systems, namely PSD, generalizes the parameter beta in the extended channel matrix. It is shown that for M-ary PSK (M-PSK) signal, the PSD is always an optimal decoder irrespective of beta. In addition, with appropriately set the value of beta the PSD can operate at optimal low, i.e. minimum, computational load. In this work, from computer simulation, the trend of impact of beta on the complexity of the detection is presented.