• Title/Summary/Keyword: precoder design

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Progressive Linear Precoder Design for Multiple Codewords MIMO ARQ Systems with ARQ Bundling Feedback

  • Zhang, Zhengyu;Qiu, Ling
    • Journal of Communications and Networks
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    • v.14 no.2
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    • pp.199-205
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    • 2012
  • This work investigates the progressive linear precoder design for packet retransmissions in multi-input multi-output (MIMO) systems with multiple codewords and automatic repeat request (ARQ) bundling feedback. Assuming perfect channel state information, a novel progressive linear ARQ precoder is proposed in the perspective of minimizing the packet error rate. We devise the ARQ precoder by combining power loading and sub channel pairing between current retransmission and previous transmissions. Furthermore, we extend the design to the case that the channel estimation error exists. Numerical results show that the proposed scheme can improve the performance of MIMO ARQ systems significantly regardless of the channel estimation error.

SLNR-based Precoder Design in Multiuser Interference Channel with Channel Estimation Error

  • Seo, Bangwon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.1
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    • pp.40-52
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    • 2020
  • In this paper, we consider a precoder design problem for multiuser interference channel. Most of the conventional schemes for precoder design utilize a signal-to-interference-plus-noise ratio (SINR) as a cost function. However, since the SINR metric of a desired transmitter-receiver pair is a function of precoding vectors of all transmitters in the multiuser interference channel, an analytic closed-form solution is not available for the precoding vector of a desired transmitter that maximizes the SINR metric. To eliminate coupling between the precoding vectors of all transmitters and to find a closed-form solution for the precoding vector of the desired transmitter, we use a signal-to-leakage-plus-noise ratio (SLNR) instead as a cost function because the SLNR at a transmitter is a function of the precoding vector of the desired transmitter only. In addition, channel estimation errors for undesired links are considered when designing the precoding vector because they are inevitable in a multiuser interference channel. In this case, we propose a design scheme for the precoding vector that is robust to the channel estimation error. In the proposed scheme, the precoding vector is designed to maximize the worst-case SLNR. Through computer simulation, we show that the proposed scheme has better performance than the conventional scheme in terms of SLNR, SINR, and sum rate of all users.

Low Complexity Zero-Forcing Precoder Design for MISO Broadcast Channels Under Per-Antenna Power Constraints (안테나 당 전력 제한 조건을 갖는 다중-입력 단일-출력 브로드캐스트 채널에서의 저복잡도 제로포싱 프리코더 설계)

  • Park, Hongseok;Jang, Jinyoung;Jeon, Sang-Woon;Chae, Hyukjin;Cha, Hyun-Su;Kim, Donghyun;Kim, Dong Ku
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.9
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    • pp.1010-1019
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    • 2016
  • The K-user multiple-input single-output broadcast channel is considered under per-antenna power constraints, i. e., each transmit antenna must satisfy its own power constraints. A low complexity zeroforcing(ZF) precoder is proposed when the number of transmit antennas M is greater than K. The proposed precoder design significantly reduces computational complexity for the precoder construction while attaining the sum spectral efficiency close to that achievable by the optimal ZF precoder.

Joint Lattice-Reduction-Aided Precoder Design for Multiuser MIMO Relay System

  • Jiang, Hua;Cheng, Hao;Shen, Lizhen;Liu, Guoqing
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.7
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    • pp.3010-3025
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    • 2016
  • Lattice reduction (LR) has been used widely in conventional multiple-input multiple-output (MIMO) systems to enhance the performance. However, LR is hard to be applied to the relay systems which are important but more complicated in the wireless communication theory. This paper introduces a new viewpoint for utilizing LR in multiuser MIMO relay systems. The vector precoding (VP) is designed along with zero force (ZF) criterion and minimum mean square error (MMSE) criterion and enhanced by LR algorithm. This implementable precoder design combines nonlinear processing at the base station (BS) and linear processing at the relay. This precoder is capable of avoiding multiuser interference (MUI) at the mobile stations (MSs) and achieving excellent performance. Moreover, it is shown that the amount of feedback information is much less than that of the singular value decomposition (SVD) design. Simulation results show that the proposed scheme using the complex version of the Lenstra--Lenstra--Lovász (LLL) algorithm significantly improves system performance.

New Design for Linear Complex Precoding over ABBA Quasi-Orthogonal Space-Time Block Codes

  • Ran, Rong;Yang, Jang-Hoon;An, Chan-Ho;Kim, Dong-Ku
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.12C
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    • pp.1062-1067
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    • 2008
  • ABBA codes, a class of quasi-orthognal space-time block codes (QoSTBC) proposed by Tirkkonen and others, allow full rate and a fast maximum likelihood (ML) decoding, but do not have full diversity. In this paper, a linear complex precoder is proposed for ABBA codes to achieve full rate and full diversity. Moreover, the same diversity produce as that of orthogonal space-time block code with linear complex precoder (OSTBC-LCP) is achieved. Meanwhile, the size of the linear complex precoder can be reduced by half without affecting performance, which means the same complexity of decoding as that of the conventional ABBA code is guaranteed.

Minimum Distance based Precoder Design for General MIMO Systems using Gram Matrix

  • Chen, Zhiyong;Xu, Xiaodong
    • Journal of Communications and Networks
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    • v.17 no.6
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    • pp.634-646
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    • 2015
  • Assuming perfect channel state information (CSI) at the transmitter and receiver, the optimization problem of maximizing the minimum Euclidean distance between two received signals by a linear precoder is considered for multiple-input multiple-output (MIMO) systems with arbitrary dimensions and arbitraryary quadrature amplitude modulation (QAM) input. A general precoding framework is first presented based on the Gram matrix, which is shown for 2-dimensional (2-D) and 3-dimensional (3-D) MIMO systems when employing the ellipse expanding method (EEM). An extended precoder for high-dimensional MIMO system is proposed following the precoding framework, where the Gram matrix for high-dimensional precoding matrix can be generated through those chosen from 2-D and 3-D results in association with a permutation matrix. A complexity-reduced maximum likelihood detector is also obtained according to the special structure of the proposed precoder. The analytical and numerical results indicate that the proposed precoder outperforms the other precoding schemes in terms of both minimum distance and bit error rate (BER).

Bandwidth-Efficient Precoding Scheme for Downlink Smart Utility Networks

  • Kim, Byung Wook
    • Journal of Korea Multimedia Society
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    • v.17 no.8
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    • pp.1012-1019
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    • 2014
  • The emerging smart utility networks (SUN) provide two-way communications between smart meters and smart appliances for purpose of low power usage, low cost, and high reliability. This paper deals with a bandwidth-efficient communication method based on the hidden pilot-aided scheme using a precoder in downlink SUN suitable for high-rate multimedia applications. With the aid of the design of a precoder and a superimposed hidden pilot, it is possible to estimate the channel without loss of bandwidth. In the channel estimation procedure, the inevitable data interference, which degrades the performance of channel estimation, can be reduced by the precoder design with an iterative scheme. Computer simulations show that the proposed scheme outperforms the conventional method in terms of achievable data rate, especially when a large number of subcarriers are employed.

Equal Gain Block Decomposition Methods for Multiuser MIMO Networks

  • Hwang, Insoo;Kang, Inseok;Hwang, Intae;You, Cheolwoo
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.3
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    • pp.1156-1173
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    • 2021
  • In this paper, we propose a new joint precoder and postcoder design strategy to support multiple streams per user in multiuser multiple-input multiple-output (MIMO) systems. We propose two step precoding strategies using equal channel gain decomposition and block diagonalization at the transmitter. With the proposed precoder, the multiuser MIMO channel can be decomposed into multiple parallel channels with equal channel gain per user. After applying receive postcoder which is generated and sent by the transmitter, we can use ML based decoder per stream to achieve full receive diversity. Achievable sum rate bound and diversity performance of the proposed algorithm are presented with feedback signaling design and quantitative complexity analysis. Simulation results show that the proposed algorithm asymptotically approaches to the sum rate capacity of the MIMO broadcast channel while maintaining full diversity order.

Design of New Differential Space-Time Modulation Using Real Precoder (실수 선부호기를 이용한 새로운 차등 시공간 변조 설계)

  • Kim, Hong-Jung;Kim, Jun-Ho;Kim, Cheol-Sung;Jung, Tae-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.1A
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    • pp.1-7
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    • 2012
  • The conventional Zhu's differential space-time modulation(DSTM) based on quasi-orthogonal design adopted a complex precoder in order to allow an independent joint detection of two complex symbols without any channel informations at a receiver. In this paper, by simply replacing the complex precoder used in Zhu's DSTM with a real precoder, a new DSTM is presented for four transmit antennas. The real precoder enables the receiver to decode two real symbols pair separately, and thus the new DSTM has greatly reduced decoding complexity compared to the Zhu's DSTM. By computer simulation results, the proposed scheme is shown to exhibit almost identical or improved error performance compared to the existing DSTMs.

Joint Base Station and Relay Precoder Design with Relay Local Channel State Information for Multi-relay Aided Multi-user All-MIMO System (다중 릴레이, 다중 사용자 All-MIMO 시스템에서 릴레이 지역 채널 정보를 사용한 기지국 및 릴레이 전처리기 공동 설계 기법)

  • Cho, Young-Min;Jang, Seung-Jun;Kim, Dong-Ku
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.6A
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    • pp.405-419
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    • 2012
  • In this paper, we propose a joint base station(BS) and relay precoders design in multi-relay aided multi-user all-multiple-input multiple-output(MIMO) system. The design criterion is to minimize user sum mean square error(SMSE) with relay sum power constraint(RSPC) where only local channel state information(CSI)s are available at relays. Local CSI at a relay is defined as the CSI of the channel which the relay itself accesses, out of among all the 1st hop and the 2nd hop channel in the system. With BS precoder structure which is concatenated with block diagonalization(BD) precoder, each relay can determine its own precoder using only local CSI. Proposed scheme is based on sequential iteration of two stages; stage 1 determines BS precoder and relay precoders jointly with SMSE duality, and stage 2 determines user receivers. Proposed scheme can be demonstrated theoretically to be always converge. We verify that proposed scheme outperforms simple amplify-and-forward(SAF), MMSE relay, and proposed schemes in [1] in terms of both SMSE and sum-rate performances.