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The optimal diversity-multiplexing-delay tradeoff for the multi- input multi-output (MIMO) automatic repeat request (ARQ) channel can be achieved using an incremental redundancy lattice space- time codes. The optimal tradeoff has been shown in to be achieved using a list lattice decoder for joint detection and decoding. However, such decoder suffers from high computational complexity for low-to-moderate...
In this paper, results on the mutual information of MIMO transmission over spatially correlated channels in slow fading environments are presented. Different receiver techniques such as optimal maximum likelihood detection, parallel layer detection, successive interference cancellation detection and linear detection are compared. The transmit signals are derived from finite signal alphabets such as...
In this paper, we design the optimal precoding matrices for amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay networks. Specifically, we consider a dual-hop relay network and minimize the total power consumed by source and relay under predetermined quality of service (QoS) constraints, i.e., mean square error (MSE) constraints. By using majorization theory, we simplify the matrix-valued...
In multiuser multiple-input multiple-output (MIMO) downlink systems, orthogonal space division multiplexing (OSDM) techniques have been studied to approach the optimum performance of dirty paper coding with low complexity. Assuming a large number of users in the multiuser system, a proper user scheduling is needed to utilize the OSDM. In addition, the performance of the chosen users can be maximized...
In this paper, we present a low-complexity coordinated beamforming transmission scheme for multiuser multiple-input-single-output (MISO) systems. With a minimum overhead signaling, the proposed scheme selects the beamforming vector and users while considering the interference from other cells. We develop the exact analytical expressions of the ergodic sum-rate for the resulting system for dual-cell...
The maximum SNR loss between equal gain transmission (EGT) and the optimal scheme, i.e. maximum ratio transmission (MRT) is 1:05 dB in MISO channels. However, little is known about the performance loss of EGT in MIMO channels, since there is no simple closed-form solution available for the best EGT in MIMO channels. In this study, an EGT design for MIMO channels is proposed and its performance is...
We consider robust receiver design in uncoded multiple-input multiple-output (MIMO) wireless communication systems. In practical systems, the channel state information (CSI) available at the receiver is often imperfect due to measurement errors, quantization errors and many other sources of errors. Consequently, using the erroneous CSI for decoding the transmitted symbols will significantly degrade...
We propose a cooperative orthogonal space-time block codes (OSTBC) transmission scheme in the adaptive-gain amplify-and-forward MIMO relaying with NS source antennas, NR relay antennas, and ND destination antennas, and analyze the asymptotic performance of the proposed scheme. Specifically, we explore the instantaneous channel state information (CSI) of source-to-relay channel and design an OSTBC...
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...
The use of hybrid automatic-repeat-request (HARQ) with multi-antenna systems (MIMO) promises high throughput with high reliability in broadband wireless communication systems. One of the combining methods in MIMO-HARQ is by directly optimizing the log-likelihood ratio (LLR) values instead of compensating the multiple signal-to-interference-and noise power ratios (SINRs) as in conventional combining...
We design non-codebook-based Multiple-Input Multiple-Output (MIMO) precoding schemes using multiple cell-specific reference signals patterns for the time division duplex (TDD) mode of LTE, where channel reciprocity can be exploited. Previously proposed non-codebook-based precoding schemes typically use UE specific reference signals for demodulation. Cell specific reference signals are however always...
This paper presents system level downlink performance evaluation results for the TDD based LTE-Advanced networks utilizing some of the most recent technologies for mobile systems. The main enhanced technology components used in the systems include multi-user (MU)-MIMO, intra-site coordinated multipoint (CoMP) transmission and space-time-frequency proportional fair scheduling. Performance comparison...
This paper deals with the superposition coding (SPC) scheme in multiple-input multiple-output two-way relay channels subject to imperfect channel estimation. We determine the achievable rate region and the related channel estimation error degradation and we show how the available power is split between the two bi-directional data flows in order to maximize the system performance and to support fairness...
In this paper, we consider the multiple base station cooperative transmission, a new technology being developed to lift the interference limits on wireless network. In practice, the biggest challenge facing multiple base station collaboration is the stringent requirement of the high-speed backbone to enable information exchange, especially for large deployment. We address this backbone issue and propose...
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...
To reduce the cost and complexity of receiver without losing much diversity gain, we propose an antenna selection scheme for MIMO systems employing non-constant envelope mapping. By detection of the received signal and a simplified process without any knowledge of channel statement information, this scheme can approach the ideal selection strategy. Single carrier system and STC-OFDM (space-time-code...
In this paper, we investigate the impact of the transmit spatial correlation on the performance of the spatial multiplexing Multiple-Input Multiple-Output (MIMO) Multi-User (MU) Ultra-WideBand (UWB) system in which a pre-equalizer and a Time Reversal (TR) pre-filter are deployed at the transmitter. The combination of the pre-equalizer and the pre-filter is to mitigate the Multiple-Stream Interference...
In this paper we evaluate a recently proposed multiple-input multiple-output (MIMO) system called the Layered Steered Space-Time Codes (LSSTC). The LSSTC system is evaluated for multi-user environments where scheduling can be used to increase the system capacity by harnessing the multi-user diversity. This evaluation is done by comparing the capacity and the probability of error for several combinations...
This paper presents throughput performance results when using joint and independent modulation and coding scheme (MCS) selections in adaptive modulation and coding (AMC) for maximum likelihood detection (MLD) based signal detection in 4-by-4 Multiple-Input Multiple-Output (MIMO) multiplexing. We show by computer simulation that joint MCS selection achieves the maximum total throughput, since the best...
This paper considers the performance enhancement of orthogonal space time block coded (OSTBC) multiple-input multiple-output system based on an optimal training strategy. Pairwise error probability (PEP) based performance analysis provides us the training design tools as well as a generic expression for the performance improvement due to optimal training compared to the conventional case for OSTBC...
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