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pre-coding for MIMO Systems in Frequency-Selective Fading Channels

WIRELESS PERSONAL COMMUNICATIONS 2010年第4期55卷 591-605页

作者： Rahhal, Jamal S. Abu-Al-Nadi, Dia I. Univ Jordan Dept Elect Engn Amman Jordan

Multiple input multiple output (MIMO) systems showed good utilization of channel characteristics. In MIMO systems multiple signals are transmitted using multiple antenna system. This provides each receiver the combined signals and hence, array processing techniques helps in reducing the effects of interference among them. In this paper we devise the use of pre-coded MIMO system to reduce the effects of frequency selectivity and hence, enhance the systems capacity and/or reduce the bit error rate. In this technique we introduce a temporal pre-coder on each antenna signal;this creates a deterministic multi-path signals similar to signals received when the channel is multi-path fading channel. The same antenna signal will arrive at each receiver forming orthogonal sub-space and the receiver will be simple add and delay of the received signals. Ant colony optimization is used in this paper to select the best pre-code. Results showed that we can diagonalize the channel matrix and practically eliminate the interference for frequency selective fading channel. Simulation of two transmitting two receiving antennas pre-coded MIMO system showed that the capacity can be doubled.

关键词： MIMO ACO pre-coding RAKE

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pre-coding OAM Based MIMO System for Multi-User Communications

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IEEE ACCESS 2022年 10卷 125411-125420页

作者： Alamayreh, Ahmad Qasem, Nidal Rahhal, Jamal S. Al Ahliyya Amman Univ Elect & Commun Engn Dept Amman 19328 Jordan Univ Jordan Dept Elect Engn Amman 11942 Jordan

Recently, orthogonal Orbital Angular Momentum (OAM) modes of electromagnetic waves have been widely applied to achieve high spectral efficiency in the radio and microwave regimes. This study investigates utilizing multimodal OAM carrying waves in communications between a central unit and distributed receiving units. Accommodated by a planner grid-array of antenna elements and backed by appropriate pre-coding, the central unit can transmit to each receiving unit multi-OAM modes. A receiving unit comprises a simple circular array. pre-coding at the transmitting unit is a two-fold process: preventing user-to-user interference and enforcing any predetermined combination of OAM modes to reach its destination. Accordingly, the parallel transmission of multiple channels to each receiver is possible. Channels aimed at the same receiver are distinguished by different modes, but the same group of modes can be simultaneously used upon transmission to other receivers. The numerical results show that significant increase in the transmission capacity is achieved. For instance, in a system including 6 receivers, 25 channels are delivered in parallel to each receiver while maintaining an acceptable low bit-error rate. Results are judged by considering the theoretical single-user quadrature phase shift keying modulation performance as a benchmark for comparison. This study also examines channel perturbations when interfering modes exist. In addition, it overcomes many typical limitations with the utilization of OAM-based solutions in radio, such as the need for transmitter-receiver alignment. The proposed system also solves the problem of wave divergence at high OAM modes, thereby avoiding the exclusion of using these modes in transmission.

关键词： Antenna array interference MIMO multi-user OAM perturbation pre-coding subspace

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Differential Spatial Modulation with Lattice Reduction Aided pre-coding

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IETE JOURNAL OF RESEARCH 2024年第2期70卷 1142-1149页

作者： Kim, Sangchoon Dong A Univ Dept Elect Engn Nakdong Daero 550beon Gil Busan 604714 South Korea

This paper presents a pre-coding scheme for recently proposed differential spatial modulation (DSM) systems. It employs a lattice reduction (LR) aided pre-coding approach. An approximated upper bound on average bit error rate (BER) is semi-analytically derived. It is analytically shown that it can achieve a full diversity gain. That is, the performance analysis demonstrates that the LR-aided pre coding DSM (LR-PDSM) systems with N-T transmit antennas and N-R receive antennas can achieve the maximum transmit diversity order of N-T. Meanwhile, it is well-known that the diversity order attained by the conventional zero-forcing (ZF) pre-coding is given as N-T - N-R + 1. Simulation results verify the approximated theoretical analysis and show that LR-aided ZF pre-coding is capable of improving the BER performance of the conventional ZF pre-coding based DSM systems under the same spectral efficiency.

关键词： Lattice reduction (LR) Multiple input multiple output (MIMO) Pairwise error probability (PEP) pre-coding Spatial modulation (SM) Zero-Forcing (ZF)

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Multiuser pre-coding Aided Quadrature Spatial Modulation for Large-Scale MIMO Channels

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China Communications 2018年第11期15卷 62-69页

作者： Fatang Chen Kang Yang Pingping Xing Huan Zhang Yanan Jiang College of Communication and Information Engineering Chongqing University of Posts and Telecommunications

pre-coding aided quadrature spatial modulation(PQSM) is a promising multiple input multiple output(MIMO) transmission technology. The multiuser(MU) detection in PQSM system is investigated in this paper. Based on the known channel state information, pre-coding matrix is designed to pre-process the in-phase and quadrature signals of quadrature spatial modulation(QSM) to reduce the inter-channel interference. In order to lower the complexity at the receiver brought by the orthogonality of the PQSM system, an orthogonal matching pursuit(OMP) detection algorithm and a reconstructed model are proposed. The analysis and simulation results show that the proposed algorithm can obtain a similar bit error rate(BER) performance as the maximum likelihood(ML) detection algorithm with more than 80% reduction of complexity.

关键词： pre-coding generalized quadra-ture spatial modulation bit error performance maximum likelihood

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Flexible photonic generation of frequency multiplication millimeter-wave vector signal based on dynamic pre-coding algorithm with dispersion compensation

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OPTICS COMMUNICATIONS 2019年 435卷 232-238页

作者： Li, BoWen Zhang, Lijia Zhang, Qi Xin, Xiangjun Pan, Xiaolong Zhang, Wei Tian, Qinghua Tao, Ying Liu, Naijin Wang, Yongjun Tian, Feng Beijing Univ Posts & Telecommun Sch Elect Engn State Key Lab Informat Photon & Opt Commun Beijing Key Lab Space Ground Interconnect & Conve 10 Xitucheng Rd Beijing 100876 Peoples R China China Acad Space Technol 104 Youyi Rd Beijing 100094 Peoples R China

The flexible photonic generation of millimeter-wave (mm-wave) vector signal adopting frequency multiplication enabled by two paralleled phase modulators and pre-coded radio frequency (RF) signals based on dynamic precoding algorithm is proposed and demonstrated. One driving signal has the original phase information and a phase deviation for dispersion compensation while the other signal has an opposite phase information and the same compensation phase. The amplitude depends on that of the regular vector symbol and the ratio of driving voltage to half-wave voltage of the phase modulator (PM). Two RF signals modulate the identical light waves from one laser via phase modulators respectively. The light waves are then transmitted over a fiber link after the selection of proper orders of harmonics by the wavelength selective switch (WSS). M the receiver, the optical signal is applied directly to a photodetector (PD) to generate the mm-wave vector signal at the desired frequency. The simulation of proposed scheme with radio over fiber (RoF) link transmission has been build. The result shows that the error vector magnitude (EVM) of generated 60 GHz, 100 GHz, and 140 GHz 16 quadrature-amplitudemodulation (QAM) signals of 1 Gb/s is no more than 20% after 80 km fiber transmission when the power into PD is no less than -10 dBm under ideal condition.

关键词： Mm-wave generation pre-coding Dispersion compensation Frequency multiplication RoF

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A robust pre-coding and hybrid equalization assisted MIMO-MU visible light communication system for QoS centric indoor communication

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TELECOMMUNICATION SYSTEMS 2019年第3期72卷 457-470页

作者： Ali, Tanweer Balani, Warsha Manipal Acad Higher Educ Manipal Inst Technol Dept Elect & Commun Engn Manipal Karnataka India REVA Univ Sch Elect & Commun Bangalore Karnataka India

The exponential rise in wireless communication demands and allied applications have revitalized academia-industries to develop an efficient and potential solution. Furthermore, the high-pace increasing scarcity of radio spectrum has also alarmed researchers to achieve better Quality of Service (QoS) centric solution. To meet such demands Visible Light Communication (VLC) systems have gained global attention;however, up surging high rate, range and reliability (3R) needs demand better performance. Towards these goals, Multiple Input Multiple Output (MIMO) based VLC systems is an efficient approach;though its efficacy under Multiple Users (MU) conditions remains least explored. Enabling MIMO-MU based VLC can achieve 3R objectives effectively;however, factors like multipath attenuation, interferences and varied impairment-affects makes classical approached confined. The MIMO-MU VLC systems require robust error, noise or interference resilient transmission even under adverse conditions such as non-linear LED, multipath attenuation and interference. Towards these objectives, in this paper a highly robust MIMO-MU VLC system is developed that incorporates an augmented MIMO channel design and combined pre-coding and post equalization schemes. To alleviate major interference probability in MIMO-MU environment, proposed model incorporates time (delay)-multiplexing based data transmission followed by signal adaptive precoding and Volterra Kernel based Hybrid-equalizer. This approach enables interference and noise removal as well as LED non-linearity handling under MIMO-MU VLC communication. The use of a Volterra Kernel based Decision Feedback Equalization with both linear as well as non-linear equalization enables proposed VLC system to exhibit low Bit Error Rate with low modulation index and taps, that optimizes trade-off between performance as well as complexity.

关键词： Visible light communication QoS pre-coding Hybrid equalization MIMO-MU VLC systems

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Generalised pre-coding Aided Spatial Modulation

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2013年第11期12卷 5434-5443页

作者： Zhang, Rong Yang, Lie-Liang Hanzo, Lajos Univ Southampton Sch ECS Southampton SO17 1BJ Hants England

A new Multiple Input Multiple Output (MIMO) transmission scheme termed as Generalised pre-coding aided Spatial Modulation (GPSM) is proposed, where the key idea is that a particular subset of receive antennas is activated and the activation pattern itself conveys useful information. This is in contrast to the previously proposed Spatial Modulation (SM) schemes, which operated by activating a specific subset of transmit antennas. We provide both analytical and numerical results characterizing the GPSM scheme proposed for both conventional as well as for large-dimensional MIMO configurations subject to both realistic imperfect Channel State Information at the Transmitter (CSIT) and to the low-rank approximation invoked for large-dimensional MIMO configurations. We also design a so-called reinforcement matrix for attaining substantial performance improvements for our proposed GPSM scheme. Our investigations show that the GPSM scheme constitutes a flexible alternative to the state-of-the-art MIMO transmission schemes, especially because it is capable of achieving a high throughput. Moreover, the benefits of mapping information to the spatial domain rather than relying on conventional modulation has substantial benefits in the medium to high Signal to Noise Ratio (SNR) region. Quantitatively, GPSM is capable of supporting the same throughput as the conventional full-multiplexing gain based MIMO arrangements at an SNR gain of about 1dB at the same receiver complexity. Furthermore, the reinforcement matrix aided GPSM scheme attains a further 3-4dB performance improvement as compared to the conventional GPSM scheme.

关键词： MIMO spatial modulation pre-coding

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Minimum Sum-Mean-Square-Error Frequency-Domain pre-coding for Downlink Multi-User MIMO System in the Frequency-Selective Fading Channel

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2017年第6期16卷 3573-3589页

作者： Yu, Qi-Yue Guo, Ji-Chong Gao, Shu-Ying Meng, Wei-Xiao Xiang, Wei Harbin Inst Technol Commun Res Ctr Harbin 150001 Peoples R China James Cook Univ Coll Sci & Engn Townsville Qld 4811 Australia Sumavis Technol Co Ltd Beijing 100000 Peoples R China

This paper proposes a new frequency-domain pre-coding algorithm for the downlink multi-user MIMO system in a frequency-selective fading channel, where each user is equipped with multiple antennas. The proposed algorithm is based on the minimum sum-mean-square-error (Min-SMSE) criterion, which is able to eliminate both the multi-user and multi-antenna interferences, resulting in an improved bit error rate (BER) performance. Compared with the traditional optimal Min-SMSE algorithm, the proposed algorithm can reduce the computational complexity through simplifying the iterative and power allocation processes. Furthermore, the theoretical BER and ergodic sum-rate are derived in detail. In addition, we define and analyze the complexity of the pre-coding algorithms. Simulation results show that the proposed algorithm compares favorably with the optimal Min-SMSE and traditional block diagonalization (BD) algorithms in the sense of the ergodic sum-rate due to the approximately equal power allocation. The BER performance of the proposed algorithm is close to that of the optimal one and much better than that of the BD algorithm in both the uncorrelated and correlated channels. Moreover, the computational complexity of the sub-optimal Min-SMSE algorithm is significantly less than that of its optimal counterpart, especially in the low SNR region.

关键词： Multi-user MIMO pre-coding block diagonalization Min-SMSE frequency-selective fading channel frequency-domain equalization (FDE)

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Subset Vector Perturbation pre-coding for MU-MIMO Downlink Systems

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IEEE ACCESS 2018年 6卷 12405-12411页

作者： Tang, Jie Bian, Xin Wang, Fang Tian, Jinfeng Li, Mingqi Chinese Acad Sci Shanghai Adv Res Inst Shanghai 201210 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China ShanghaiTech Univ Sch Informat Sci & Technol Shanghai 201210 Peoples R China Nanjing Univ Posts & Telecommun Nanjing 210003 Jiangsu Peoples R China

Multi-user multiple input multiple output (MU-MIMO) is a basic technique which has been widely investigated for its ability to increase system capacity. However, the inter-user interference (IUI) is one of the obstacles to obtain system capacity. With the help of pre-coding technique, the IUI can be canceled or reduced at the base station (BS). Vector perturbation (VP) is one of the most celebrated pre-coding schemes that can approach system capacity. By perturbing users' data vector with a certain integer vector offset at the BS, the VP scheme can offer the users a higher effective signal-to-noise ratio. To reach the theory bound of VP, the BS has to select the optimal integer vector from all candidate integer vectors globally. This exhaustive search has been proved to be NP-hard, which is hard to be implemented. In this paper, we analyze several state-of-the-art modified low-complexity VP schemes and propose the subset VP (SVP) scheme to reduce the complexity of the VP. The basic principle of the SVP is that some vectors are selected as the optimal vector with high probability, whereas the others are scarcely selected. So, we try to form a subset consists of vectors with a relatively higher probability. First, we calculate the probability of all candidate vectors which have been selected as the optimal vector. Second, we propose a method to divide all vectors into several subgroups. Vectors in the same subgroup have a similar probability, whereas vectors in different subgroups have distinguished probability. Third, we build a subset that is comprised of several subgroups in which vectors have a relatively higher probability. Simulation results show that we get almost the same bit-error rate performance with a significant complexity reduction.

关键词： MIMO pre-coding vector perturbation subset

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pre-coding using Different Detection Algorithms in MIMO System 3

Pre-Coding using Different Detection Algorithms in MIMO Syst...

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International Conference on Current Trends in Computer, Electrical, Electronics and Communication (CTCEEC)

作者： Sharma, Purnima K. Sharma, Dinesh Gupta, Akansha SVEC ECE Dept Tadepalligudem India GE Univ CSE Dept Dehra Dun India

ISBN: (纸本)9781538632437

pre-coding is a general understanding of beam-forming to achieve the transmission diversity of the signal. Basically transmitter sends the information which is already coded according to the known knowledge about the channel conditions to the receiver. The pre-coding technique leads to achieve a good performance by eliminating the degradation effects even in the correlation environment upon the channel in the communication system. In this paper, the different detection algorithms: Zero forcing (ZF), Minimum mean square error (MMSE) and Block diagonalization (BD) are used in pre-coding. Many solutions have been proposed for the Co-Channel Interference problem. The main aim of this paper is to select the most suitable coding techniques to adopt. The analysis is carried by assuming the channel as Rayleigh and modulation scheme is QPSK with 4x4 MIMO system.

关键词： pre-coding Detection algorithms Channel state information (CSI) Zero forcing (ZF) Minimum mean square error (MMSE) Block diagonalization (BD)

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