In this paper we consider the design of minimum mean square error (MMSE) transceivers for non-regenerative multiuser multiple-input multiple-output (MIMO) relay systems, where the main challenge resides in the joint o...
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ISBN:
(纸本)9781467310680
In this paper we consider the design of minimum mean square error (MMSE) transceivers for non-regenerative multiuser multiple-input multiple-output (MIMO) relay systems, where the main challenge resides in the joint optimal design of the precoder to be used at the base station and the relaying algorithms. We propose the use of non-linear precoding techniques, such as Tomlinson-Harashima precoding (THP) and vector precoding (VP), at the downlink relayed transmission scenario with the aim of outperforming the more common linear strategies. In order to reduce the computational cost of the proposed schemes, we propose a novel suboptimal matrix design approach for VP transmission. Provided simulation results show that the proposed non-linear precoding schemes outperform the best MIMO-AF relaying architectures in the literature, even when a reduced-complexity suboptimal strategy is adopted, considering both BER performance and mean square error minimization.
non-linear precoding gained attention recently in 3GPP (the third generation partnership project) as a possible technique to improve the performance of multi-user multiple input multiple output (MIMO). In this paper, ...
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ISBN:
(纸本)9781538681466
non-linear precoding gained attention recently in 3GPP (the third generation partnership project) as a possible technique to improve the performance of multi-user multiple input multiple output (MIMO). In this paper, research and standardization activities related non-linear precoding for 3GPP are described. Implementation, performance evaluation of nonlinearprecoding and analysis of 3GPP specification impact are presented in this paper. Both system and UE throughput evaluation results, conducted at both 5GHz and 30GHz, demonstrate that non-linear precoding yield superior performance compared to linearprecoding. In addition, two novel non-linear precoding based transmission schemes which require lower computational complexities than conventional non-linear precoding schemes are proposed. The first scheme separates UEs into linearly precoded and nonlinearly precoded UEs, reducing computational complexities required by non-linear precoding. The second scheme is a precoding scheme which intentionally introduces inter-UE interference through linearprecoding and implements nonlinearprecoding to remove inter-UE interference;multi-user diversity gain and reduction in computational complexity are obtained simultaneously. Finally, new abstraction performance metrics for the proposed schemes are presented. The simulation results demonstrate that the proposed methods outperform linearprecoding techniques and offer a tradeoff between computational complexity and throughput performance.
non-linear precoding (NLP) scheme for downlink multiuser multiple-input multiple-output (DL-MU-MIMO) transmission has received much attention as a promising technology to achieve high capacity within the limited bandw...
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non-linear precoding (NLP) scheme for downlink multiuser multiple-input multiple-output (DL-MU-MIMO) transmission has received much attention as a promising technology to achieve high capacity within the limited bandwidths available to radio access systems. In order to minimize the required transmission power for DL-MU-MIMO and achieve high spectrum efficiency, Vector Perturbation (VP) was proposed as an optimal NLP scheme. Unfortunately, the original VP suffers from significant computation complexity in detecting the optimal perturbation vector from an infinite number of the candidates. To reduce the complexity with near transmission performance of VP, several recent studies investigated various efficient NLP schemes based on the concept of Tomlinson-Harashima precoding (THP) that applies successive pre-cancellation of inter-user interference (IUI) and off sets the transmission vector based on a modulo operation. In order to attain transmission performance improvement over the original THP, a previous work proposed Minimum Mean Square Error based THP (MMSE-THP) employing IUI successive pre-cancellation based on MMSE criteria. On the other hand, to improve the transmission performance of MMSE-THP, other previous works proposed Ordered MMSE-THP and Lattice-Reduction-Aided MMSE-THP (LRA MMSE-THP). This paper investigates the further transmission performance improvement of Ordered MMSE-THP and LRA MMSE-THP. This paper starts by proposing an extension of MMSE-THP employing a perturbation vector search (PVS), called PVS MMSE-THP as a novel NLP scheme, where the modulo operation is substituted by PVS and a subtraction operation from the transmit signal vector. Then, it introduces an efficient search algorithm of appropriate perturbation vector based on a depth-first branch-and-bound search for PVS MMSE-THP. Next, it also evaluates the transmission performance of PVS MMSE-THP with the appropriate perturbation vector detected by the efficient search algorithm. Computer simu
This paper proposes an XOR physical layer network coding (XOR-PLNC) with non-linear precoding for quadrature amplitude modulations (QAMs) in bi-directional MIMO relay systems. The proposed XOR-PLNC applies power loadi...
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This paper proposes an XOR physical layer network coding (XOR-PLNC) with non-linear precoding for quadrature amplitude modulations (QAMs) in bi-directional MIMO relay systems. The proposed XOR-PLNC applies power loading in order to improve the transmission performance. The proposed XOR-PLNC introduces a modulus adapted to channel gains. Moreover, the modulus is further reduced in cooperation with modulo operation which the non-linear precoding employs for improvement of transmission power efficiency. The use of the reduced modulus improves the energy efficiency of the signal transmission, which improves the transmission performance in the proposed XOR-PLNC. The performance is evaluated by computer simulations in bi-directional MIMO relay channels with 16QAM to 1024QAM.
This paper considers transceiver design for the cellular two-way relay channel (cTWRC), where a multi-antenna base station (BS) exchanges information with multiple single-antenna mobile stations via a multi-antenna re...
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ISBN:
(纸本)9781479935123
This paper considers transceiver design for the cellular two-way relay channel (cTWRC), where a multi-antenna base station (BS) exchanges information with multiple single-antenna mobile stations via a multi-antenna relay station. We propose a novel network coding scheme to approach the sum capacity of the cTWRC. Specifically, a new non-linear lattice-based precoding technique is proposed at the BS to pre-compensate the inter-stream interference, in order to allow efficient interference-free lattice decoding at the relay. We derive sufficient conditions for the proposed scheme to asymptotically achieve the sum capacity of the cTWRC in the high signal-to-noise ratio (SNR) regime. Numerical results show that the proposed scheme outperforms the existing schemes and is able to asymptotically achieve the cut-set bound of the cellular relay networks.
This paper considers transceiver design for the cellular two-way relay channel (cTWRC), where a multi-antenna base station (BS) exchanges information with multiple single-antenna mobile stations via a multi-antenna re...
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ISBN:
(纸本)9781479935130
This paper considers transceiver design for the cellular two-way relay channel (cTWRC), where a multi-antenna base station (BS) exchanges information with multiple single-antenna mobile stations via a multi-antenna relay station. We propose a novel network coding scheme to approach the sum capacity of the cTWRC. Specifically, a new non-linear lattice-based precoding technique is proposed at the BS to pre-compensate the inter-stream interference, in order to allow efficient interference-free lattice decoding at the relay. We derive sufficient conditions for the proposed scheme to asymptotically achieve the sum capacity of the cTWRC in the high signal-to-noise ratio (SNR) regime. Numerical results show that the proposed scheme outperforms the existing schemes and is able to asymptotically achieve the cut-set bound of the cellular relay networks.
In Constant Envelope Symbol Level precoding (CESLP), the transmitted signals by the antennas have constant amplitude regardless of the channel realization and the conveyed information symbols. Such solutions enable th...
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In Constant Envelope Symbol Level precoding (CESLP), the transmitted signals by the antennas have constant amplitude regardless of the channel realization and the conveyed information symbols. Such solutions enable the use of power-efficient components, i.e. non-linear power amplifiers and thus, are suitable for systems based on large-scale antenna arrays. In the latter systems, the hardware complexity and power consumption can be limiting factors since each antenna element requires dedicated hardware components. These components include the Digital-to-Analog Converters (DACs) that have exponential complexity and power consumption with the number of the supported resolution. To that end, in this paper, a CESLP precoding technique is presented for Multi-User Multiple Input-Multiple Output (MU-MIMO) systems with low resolution DACs. The case of a multi-carrier system employing the well-known Orthogonal Frequency Division Multiplexing (OFDM) technique is considered. The precoding design problem is formulated as a mixed discrete-continuous least-squares optimization one which is NP-hard. An efficient low complexity solution is developed based on the Cyclic Coordinate Descent (CCD) optimization framework. Simulations show that the proposed solution is able to achieve very close performance to the one of the infinite resolution CESLP precoding counterpart even though, it is based on DACs that have resolution of only a few bits.
We focus on the design of vector perturbation (VP) precoding for multiuser multiple-input-single-output (MU-MISO) broadcast channel systems where the centralized transmitter equipped with multiple antennas and communi...
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We focus on the design of vector perturbation (VP) precoding for multiuser multiple-input-single-output (MU-MISO) broadcast channel systems where the centralized transmitter equipped with multiple antennas and communicates simultaneously to multiple single-antenna receivers. While conventional VP requires the feedback of the channel matrix at the transmitter for precoding and the power scaling factor at the receivers for detection, VP precoding has so far been developed and analyzed under assumptions that the transmitter has perfect channel state information (CSI) or the receivers have perfect knowledge of the channel- and data-dependent power scaling factors. In practical limited feedback scenarios, wireless communication systems suffer from limited time and frequency resource for pilots to feed-forward information and only a quantized version of power scaling factors is available at the receivers;under such limitations, the performance of VP precoding will degrade significantly compared with ideal scenarios and would always encounter an error floor at mid-to-high signal-to-noise ratio (SNR) regions. Motivated by such observations, we propose a robust VP precoder design, which takes the imperfectness of CSI and power scaling factor jointly into account under the criterion of minimum mean-square error (MMSE). The closed-form expressions of the proposed precoder are then derived. As illustrated by the simulation results, the proposed VP precoder is less sensitive to CSI and power scaling factor imperfections compared with the classic VP precoder and other existing MMSE-based VP precoders, as it has a lower error floor when imperfectness is assumed to be fixed, and power scaling factor accuracy is shown to offer a non-linear performance gain compared with that of the linear gain CSI accuracy could offer.
Herein, a precoding scheme is developed for orthogonal frequency division multiplexing (OFDM) transmission in multiple-input multiple-output (MIMO) systems that use one-bit digital-to-analog converters (DACs) and anal...
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Herein, a precoding scheme is developed for orthogonal frequency division multiplexing (OFDM) transmission in multiple-input multiple-output (MIMO) systems that use one-bit digital-to-analog converters (DACs) and analog-to-digital converters (ADCs) at the transmitter and receiver, respectively, as a means to reduce the power consumption. Two different one-bit architectures are presented. In the first, a single user MIMO system is considered where the DACs and ADCs of the transmitter and the receiver are assumed to be one-bit and in the second, a network of analog phase shifters is added at the receiver as an additional analog-only processing step with the view to mitigate some of the effects of coarse quantization. The precoding design problem is formulated and then split into two NP-hard optimization problems, which are solved by an algorithmic solution based on the Cyclic Coordinate Descent (CCD) framework. The design of the analog post-coding matrix for the second architecture is decoupled from the precoding design and is solved by an algorithm based on the alternating direction method of multipliers (ADMM). Numerical results show that the proposed precoding scheme successfully mitigates the effects of coarse quantization and the proposed systems achieve a performance close to that of systems equipped with full resolution DACs/ADCs.
This paper focuses on the design of vector perturbation (VP) precoding for coordinated multi-point (CoMP) multi-user downlink transmission. precoding is performed by individual base stations (BSs) in a distributed man...
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This paper focuses on the design of vector perturbation (VP) precoding for coordinated multi-point (CoMP) multi-user downlink transmission. precoding is performed by individual base stations (BSs) in a distributed manner using only the downlink channel coefficients and user data local to a BS. A cascade precoder structure with an outer precoder managing the inter-cell interference (ICI) and an inner precoder performing mean-squared-error (MSE) minimization-based VP to mitigate the intra-cell interference is proposed. Three different outer precoding techniques are considered. In the first technique, the outer precoder is designed to fully eliminate the ICI by trading off the degrees of freedom (DoFs) available through multiple antennas. While the proposed technique outperforms existing conventional-VP based designs, a large portion of DoF is consumed by the ICI elimination. To overcome this issue, in the second technique, interference alignment-based outer precoding that minimizes the total leakage interference is proposed. To further improve the system performance, in the third approach, precoding by joint minimization of total leakage interference plus MSE is performed. Numerical results show that the proposed cascade precoding structure is an efficient way to use the DoF of CoMP multi-user downlink transmission.
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