Multiple transmit and receive antennas can be used to form multiple-input multiple-output (MIMO) channels to increase the capacity by a factor of the minimum number of transmit and receive antennas. In this paper, we ...
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Multiple transmit and receive antennas can be used to form multiple-input multiple-output (MIMO) channels to increase the capacity by a factor of the minimum number of transmit and receive antennas. In this paper, we propose a novel joint linear transceiver design for single-user multiple-input, multiple-output (SU-MIMO) systems employing improper signal constellations. In particular, improved minimum mean square error (MMSE) transceiver is designed based on modified cost functions, with channel mean as well as both transmit and receive correlation information at both ends. The joint design is formulated into an optimization problem. The optimum closed-form precoder and decoder are derived. Compared to the case with perfect channel state information (CSI), linear filters are added at both ends to balance the suppression of channel noise and the noise from imperfect channel estimation. The superiority of the proposed joint linear transceiver design over the conventional solutions is verified by simulation results
We study the transmission techniques in orthogonal frequency division multiplexing (OFDM) systems with imperfect channel state information at the transmitter (CSIT). We focus on the issue of utilizing the available CS...
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We study the transmission techniques in orthogonal frequency division multiplexing (OFDM) systems with imperfect channel state information at the transmitter (CSIT). We focus on the issue of utilizing the available CSIT by a single forward error control (FEC) code. We first analyze the system performance for the ideal coding case. We then develop a simple but efficient scheme for the practical coding case, which is based on joint FEC coding and linear precoding at the transmitter and iterative linear minimum-mean-square-error (LMMSE) detection at the receiver. Numerical results show that significant performances gains can be achieved by the proposed scheme.
In this paper, the design of linear leakage-based precoders is considered for multiple-input multiple-output （MIMO） downlinks. Our proposed scheme minimizes total transmit power under each user＇s signal-to-leakage-...
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In this paper, the design of linear leakage-based precoders is considered for multiple-input multiple-output （MIMO） downlinks. Our proposed scheme minimizes total transmit power under each user＇s signal-to-leakage-plus-noise ratio （SLNR） constraint. When the base station knows perfect channel state information （CSI）, suitable reformulation of design problem allows the successful application of semidefinite relaxation （SDR） techniques. When the base station knows imperfect CSI with limited estimation errors, the design problem can be solved using semidefinite program （SDP）. At the same time, it can dynamically allocate each user＇s SLNR threshold according to each user＇s channel state, so it is more feasible than other similar S1NR-based precoding methods. Simulation results show that using large SLNR thresholds, the proposed design has better bit error rate （BER） performance than maximal-SLNR precoding method at high signal-to-noise ratio （SNR）. Moreover, when the base station knows imperfect channel state information, the proposed precoder is robust to channel estimation errors, and has better BER preformance than other similar SINR-based precoding methods.
A novel equalization and precoding joint optimization algorithm is proposed in dual hop multiple input multiple output (MIMO) relay communication systems. This solution combines the equalization for the first stage an...
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ISBN:
(纸本)9781424462520
A novel equalization and precoding joint optimization algorithm is proposed in dual hop multiple input multiple output (MIMO) relay communication systems. This solution combines the equalization for the first stage and precoding for the second stage in relay system, therefore the joint optimization can be equaled with the unique optimization for the product matrix of detection and precoding, which avoid the non convergence problems in iterating process, compared with iterative optimization, the complexity burden of this algorithm is greatly reduced. And from simulation results the performance is only a little degraded. Therefore, when complexity and performance are considered, this algorithm reached a better compromise.
In this paper, we present a high-performance hybrid linear precoding scheme for the downlink of multiuser multiple-input multiple-output (MU-MIMO) systems based on the combination of an iterative modified regularized ...
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ISBN:
(纸本)9781612842332
In this paper, we present a high-performance hybrid linear precoding scheme for the downlink of multiuser multiple-input multiple-output (MU-MIMO) systems based on the combination of an iterative modified regularized block diagonalization (IMRBD) precoding and minimum mean square error (MMSE) precoding. The proposed hybrid diversity maximization (HDM) scheme aims to maximize the diversity gain by means of this dual-stage precoding strategy while maintaining relatively low complexity. The simulation results show that HDM precoding can provide comparable or even better performance than other iterative precoding schemes, including some of the more complex ones.
This paper addresses cooperation in a multicell environment where base stations (BSs) wish to jointly serve multiple users, under a constrained-capacity backhaul. We point out that for finite backhaul capacity a trade...
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This paper addresses cooperation in a multicell environment where base stations (BSs) wish to jointly serve multiple users, under a constrained-capacity backhaul. We point out that for finite backhaul capacity a tradeoff between sharing user data, which allows for full MIMO cooperation, and not doing so, which reduces the setup to an interference channel but also requires less overhead, emerges. We optimize this tradeoff by formulating a rate splitting approach in which non-shared data (private to each transmitter) and shared data are superimposed. We derive the corresponding achievable rate region and obtain the optimal beamforming design for both shared and private symbols. We illustrate how the capacity of the backhaul determines how much of the user data is worth sharing across multiple BSs.
A multiple-input multiple-output two-way relay channel consisting of two communication nodes and a full-duplex relay node in which no direct link exists between the two communication nodes is considered. We propose an...
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A multiple-input multiple-output two-way relay channel consisting of two communication nodes and a full-duplex relay node in which no direct link exists between the two communication nodes is considered. We propose an achievable scheme that employs horizontally encoded lattice codes combined with generalized singular value decomposition-based precoding for the first phase. The second phase of the proposed scheme follows the fundamentals of the previous scheme, which uses vertically encoded structural bining, with the only difference that the added codeword of the two codewords from the communication nodes, instead of those two individual codewords, is decoded and retransmitted in the proposed scheme. We show that the proposed scheme achieves the cut-set bound asymptotically as the signal-to-noise ratios of the channels tend to infinity.
linear precoding is an attractive technique to combat interference in multiple-input multiple-output systems because it reduces cost and power consumption at the receiver. Frequency division duplex systems with linear...
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linear precoding is an attractive technique to combat interference in multiple-input multiple-output systems because it reduces cost and power consumption at the receiver. Frequency division duplex systems with linear precoding acquire the channel state information at the receiver side by using supervised algorithms. Such methods make use of pilot symbols periodically provided by the transmitter. Next, this channel state information is sent to the transmitter side through a low-cost feedback channel. Thus, the available channel information allows the transmitter to adapt signals to the channel conditions. Given that pilot symbols do not convey user data, they penalize throughput, spectral efficiency, and transmission energy consumption of the system. In this work, we propose to mitigate the aforementioned limitations by combining both supervised and unsupervised algorithms to acquire the channel state information needed by the transmitter. The key idea consists in introducing a simple criterion to determine whether the channel has suffered a significant variation which requires the transmission of pilot symbols. Otherwise, when small fluctuations happen, an unsupervised method is used to track these channel variations instead. This criterion will be evaluated by considering two types of strategies for the design of the linear precoders: Zero-Forcing and Wiener criteria. (C) 2011 Elsevier B.V. All rights reserved.
We study the design optimization of linear precoders for maximizing the mutual information between finite alphabet input and the corresponding output over complex-valued vector channels. This mutual information is a n...
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We study the design optimization of linear precoders for maximizing the mutual information between finite alphabet input and the corresponding output over complex-valued vector channels. This mutual information is a nonlinear and non-concave function of the precoder parameters, posing a major obstacle to precoder design optimization. Our work presents three main contributions: First, we prove that the mutual information is a concave function of a matrix which itself is a quadratic function of the precoder matrix. Second, we propose a parameterized iterative algorithm for finding optimal linear precoders to achieve the global maximum of the mutual information. The proposed iterative algorithm is numerically robust, computationally efficient, and globally convergent. Third, we demonstrate that maximizing the mutual information between a discrete constellation input and the corresponding output of a vector channel not only provides the highest practically achievable rate but also serves as an excellent criterion for minimizing the coded bit error rate. Our numerical examples show that the proposed algorithm achieves mutual information very close to the channel capacity for channel coding rate under 0.75, and also exhibits a large gain over existing linear precoding and/or power allocation algorithms. Moreover, our examples show that certain existing methods are susceptible to being trapped at locally optimal precoders.
Crosstalk interference is the limiting factor in transmission over copper lines. Crosstalk cancellation techniques show great potential for enabling the next leap in DSL transmission rates. An important issue is the e...
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ISBN:
(纸本)9781424414833
Crosstalk interference is the limiting factor in transmission over copper lines. Crosstalk cancellation techniques show great potential for enabling the next leap in DSL transmission rates. An important issue is the effect of finite world length on performance. In this paper we provide an analysis of the performance of linear zero-forcing precoders, used for crosstalk compensation, in the presence of quantization noise. We quantify analytically the trade off between quantization level and transmission rate degradation. We demonstrate, through simulations on real lines, the accuracy of our estimates. Finally, we show how to use these estimates as a design tool for DSL linear crosstalk precoders.
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