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Multi-user multiple input and multiple output (MU-MIMO) is one of the key techniques in 3GPP Long-Term Evolution (LTE), which enhances the overall system capacity in the downlink. In order to reduce the effect of inter-user-interference in this system, it is necessary to utilize an efficient detection method at the user equipment (UE) that besides its feasibility at high data rate transmission systems...
In this paper a new maximum likelihood (ML) based detector for multi-input multi-output (MIMO) channels in spatio-temporal colored noise fields is proposed. It is assumed a Kronecker model of spatio-temporal correlation of noise. Approximate ML (AML) detection algorithm of MIMO channels is considered for two cases: known noise correlation matrix and unknown noise correlation matrix. The ML decoder...
Sparse space codes (SSC) are proposed as a novel transmission scheme for an under-determined MIMO channel. Each SSC codeword is a sparse vector of the size of the number of transmit antennas. The information is imparted through: (i) uncertainty in the positions of non-zero elements, and (ii) uncertainty in the symbol-space of non-zero elements. Basis-pursuit (BPD) and LASSO detectors are used with...
A multi-cell hybrid channel state information (CSI) feedback scheme was proposed, which has an ideal nested hierarchical structure to support not only the advanced multi-cell MIMO precoding, but also the traditional single-cell single-user and multi-user precoding transmissions. A quantization scheme for the multi-cell hybrid CSI feedback was provided, using codebook based vector-quantization for...
A unified Bit-based Probabilistic Data Association (B-PDA) detection approach is proposed for Multiple-Input Multiple-Output (MIMO) systems employing high-order Quadrature Amplitude Modulation (QAM). The new approach transforms the symbol detection process of QAM to a bit-based process by introducing a Unified Matrix Representation (UMR) of QAM. Both linear natural and nonlinear Gray bit-to-symbol...
This paper examines a type of linear beamforming for communications in interference networks. First, a receiver beamformer design is derived from a Maximum Likelihood (ML) framework with Automatic Gain Control (AGC) constraints. The studied beamformer keeps the complexity of the receiver low and it is able either to remove full coherent arrivals or to enhance them when required when different AGC...
OFDM-based multi antenna systems suffer from inaccurate channel estimates in time variant channels which lead eventually to performance degradation. Decision-directed channel estimation (DDCE) schemes have been proposed to reduce the number of reference symbols. A prediction of channel coefficients is necessary for MIMO detection, whose output is used to acquire new channel estimates recursively....
We investigate successive interference cancellation (SIC) detectors that can achieve a close to optimum BER performance in spatial multiplexed multi-input multi-output (SM-MIMO) systems. We propose a low-complexity interference suppression strategy, in which an enhanced SIC is devised by introducing the feedback diversity to combat the error propagation in decision feedback loops. In order to constrain...
This paper studies zero-forcing (ZF) detection for multiple-input multiple-output (MIMO) wireless communications systems and transmit-correlated and estimated Rician fading with realistic azimuth spread (AS) and K-factor. Due to the nonzero-mean channel gain matrix, the matrix that determines the symbol-detection signal-to-noise ratio for the spatially multiplexed streams has a noncentral Wishart...
A power/area aware design is mandatory for the MIMO (Multi-Input Multi-Output) detectors used in LTE and WiMAX standards. The 64-QAM modulation used in the MIMO detector requires more detection effort compared to the smaller constellation sizes widely implemented in the literature. In this work we propose a new architecture for the K-best detector, which unlike the popular multi-stage architecture...
This paper proposed a detection method combined the list detection with partial successive interference cancellation (SIC) based on the reciprocal lattice-reduction in MIMO system. List detection is an effective detection method for improving the performance of MIMO signal detection, but the computational expense depending on the list length is the bottleneck. To reduce the complexity of the list...
This paper proposes an MMSE detector using forward and backward reciprocal lattice reduction (LR) in MIMO systems. In the 8×8 MIMO systems, the reciprocal LR aided detection (LRAD) achieves better BER performances about 3dB than the LRAD using the conventional LLL algorithm over BER=10-5. The proposed method furthermore achieves better BER performances about 1dB than the reciprocal LRAD.
This paper proposes a lattice-reduction aided detection (LRAD) based successive interference cancellation (SIC). The proposed detector achieves as good as or better BER performances than the conventional LR aided MMSE detector and using the SIC for QPSK, 16QAM and 64QAM in the 8×8 MIMO systems. It also achieves BER curves to be as steep as or steeper than those using the maximum likelihood detector.
This paper presents the implementation details and experimental evaluation results of a high-performance multiple-input multiple-output (MIMO) detector for new generation wireless LAN systems. Performance of an IEEE 802.11n compliant FPGA-based prototype equipped with a dual MIMO processing unit is evaluated in a small office environment for both linear MMSE and lattice-reduction aided detection modes...
A novel iterative detection scheme for MIMO-OFDM systems is proposed in this work. We show that the existing detection schemes are sub-optimum and the iterative process can be optimized by utilizing the non-circular property of the residual interference after interference cancellation. Results show that the proposed iterative scheme outperforms the conventional iterative soft interference cancellation...
Spatial Modulation (SM) is a recently proposed joint coding and modulation scheme for Multiple-Input-Multiple-Output (MIMO) wireless systems, which is receiving a growing interest. SM offers a low-complexity alternative to the design of MIMO wireless systems, which avoids multiple Radio Frequency (RF) chains at the transmitter and high-complexity interference cancellation algorithms at the receiver,...
In this paper, we derive user selection criteria based on the error probability for an actually employed detector for multiuser multiple-input multiple-output (MIMO) systems. We propose a low complexity sequential user selection scheme when a lattice reduction (LR) based MIMO detector is used. We also analyze the diversity gain for combinatorial user selection approaches with a given LR-based detector...
This paper proposes a dimension reduction maximum likelihood (ML) soft demodulator for multiple-input multiple-output (MIMO) system. The proposed dimension reduction soft demodulator reduces the dimension of the search space for minimum Euclidean distance calculation by exploiting ML hard detection algorithms and can achieve significantly lower complexity than existing optimal soft demodulators based...
In recent years, lattice-reduction-aided (LRA) MIMO detection attracts much research attention because it can effectively improve MIMO detection performance. However, it causes performance degradation in the low- and mid-SNR channel especially in the high-dimensional MIMO system. Therefore, we propose a multi-stage lattice-reduction-aided (MS-LRA) MIMO detection scheme in this letter. The proposed...
This paper considers the implementation of a soft-output MMSE detector for packet-based MIMO-OFDM transmission. The paper focuses on channel-matrix preprocessing realized with a QR decomposition which needs to be carried out under tight latency constraints. We discuss how the preprocessing algorithm should be selected to meet the specific requirements of the soft-output MMSE detector. Additionally...
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