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Spectrum efficiency analysis of signal alignment-based beamspace millimetre wave MIMO-NOMA systems

IET COMMUNICATIONS 2020年第5期14卷 818-829页

作者： Salem, Ahmed Abdelaziz Benaya, A. M. El-Rabaie, Sayed Shokair, Mona Menoufia Univ Fac Elect Engn Menoufia 32952 Egypt

Non-orthogonal multiple access (NOMA) has been integrated with beamspace multi-input multi-output (MIMO) to enhance system spectrum efficiency (SE) by serving more than one user per dedicated radio frequency (RF) chain. However, balancing the system performance with significant RF reduction is still challenging. In this study, the authors propose beamspace MIMO-NOMA system based on signal alignment (SA) concept, where they will be able to tackle the issue of hardware complexity with a significant performance. Spectrum and energy efficiencies are analysed through two main stages. First, the excess degrees-of-freedom of beamspace MIMO-NOMA are exploited by SA to suppress the inter-beam/pair interference through designing user detection vectors and precoding matrix. Accordingly, a significant RF-chains reduction is provided. Second, power allocation coefficients are evaluated upon the optimal SE in order to mitigate intra-beam/pair interference. Moreover, the authors derive a tight closed formula for optimal SE based on Karush-Kuhn-Tucker analysis, which is validated by a heuristic-based optimal solution. Simulation results show a superior performance gain over orthogonal multiple access technique. Furthermore, the Monte-Carlo numerical solution depicts the marginal performance gap between the analytical and heuristic-based optimisation approach. This confirms the accuracy and rigidity of the proposed system.

关键词： optimisation antenna arrays MIMO communication precoding Monte Carlo methods spectrum efficiency analysis signal alignment-based beamspace MIMO-NOMA systems beamspace concept millimetre wave multiinput multioutput hardware complexity required radio frequency chains system capacity RF chains user numbers nonorthogonal multiple access system spectrum efficiency dedicated RF chain system performance RF reduction authors propose beamspace MIMO-NOMA signal alignment concept energy efficiencies excess degrees-of-freedom user detection vectors precoding matrix significant RF-chains reduction optimal SE Karush-Kuhn-Tucker analysis heuristic-based optimal solution superior performance gain orthogonal multiple access technique marginal performance gap analytical based optimisation approach heuristic-based optimisation approach

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Transceiver Optimization for Two-Hop AF MIMO Relay Systems With DFE Receiver and Direct Link

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IEEE TRANSACTIONS ON COMMUNICATIONS 2022年第6期70卷 4134-4145页

作者： Su, Qiao Rong, Yue Army Engn Univ PLA Coll Commun Engn Nanjing 210007 Peoples R China Curtin Univ Sch Elect Engn Comp & Math Sci Bentley WA 6102 Australia

In this paper, we consider precoding and receiving matrices optimization for a two-hop amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay system with a decision feedback equalizer (DFE) at the destination node in the presence of the direct source-destination link. By adopting the minimum mean-squared error (MMSE) criterion, we develop two new transceiver design algorithms for such a system. The first one employs an iterative procedure to design the source, relay, feed-forward, and feedback matrices. The second algorithm is a non-iterative suboptimal approach which decomposes the optimization problem into two tractable subproblems and obtains the source and relay precoding matrices by solving the two subproblems sequentially. Simulation results validate the better MSE and bit-error-rate (BER) performance of the proposed algorithms and show that the non-iterative suboptimal method has a negligible performance loss when the ratio of the source node transmission power to the relay node transmission power is small. In addition, the computational complexity analysis suggests that the second algorithm and one iteration of the first algorithm have the same order of complexity. As the first algorithm typically converges within a few iterations, both proposed algorithms exhibit a low complexity order.

关键词： Relays Receivers MIMO communication Transceivers Decision feedback equalizers Optimization matrix decomposition Amplify-and-forward MIMO relay precoding matrix decision feedback equalizer (DFE) direct link

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Secrecy precoding in MIMOME wireless communication system under partial CSI

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IET COMMUNICATIONS 2020年第13期14卷 2202-2209页

作者： Dong, Runze Wang, Buhong Cao, Kunrui Li, Xia Air Force Engn Univ Sch Informat & Nav Xian 710077 Peoples R China Natl Univ Def Technol Sch Informat & Commun Xian 710106 Peoples R China

In this study, a precoding scheme which is called singular value decomposition and null space (SVDNS) based scheme is proposed to enhance physical layer security of a multiple-input multiple-output multiantenna eavesdropper (MIMOME) system. Under the partial channel state information (CSI) of the eavesdropper, the precoding matrix for the information bearing signal is constructed firstly via SVDNS-based scheme to acquire a compromise between improving performance of the main channel and impairing that of the wiretap channel. Then the optimal power allocation over subchannels formed by precoding matrix is obtained through solving the secrecy rate maximise problem to further improve secrecy performance. After that, under the scenario that CSI of the wiretap channel is less knowable, precoding matrix for artificial noise (AN) is proposed via SVDNS-based scheme, and then the optimal power allocation between the information bearing signal and AN is obtained while optimal power allocation over subchannels is solved subsequently. Simulation results show that the SVDNS-based scheme with optimal power allocation achieves a higher secrecy rate than the existing schemes, and the SVDNS-based scheme with AN aiding could make up for the performance degradation of it without AN in the situation that CSI of the wiretap channel is more unknowable.

关键词： MIMO communication antenna arrays optimisation singular value decomposition precoding radio transmitters wireless channels telecommunication security secrecy precoding MIMOME wireless communication system partial CSI precoding scheme partial channel state information precoding matrix information bearing signal SVDNS-based scheme impairing wiretap channel optimal power allocation secrecy rate maximise problem secrecy performance singular value decomposition and null space based scheme multiple-input multiple-output multiantenna eavesdropper system

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Two-Hop AF MIMO Relay System Optimization With Own Information From the Relay Node

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2019年第4期67卷 930-945页

作者： Su, Qiao Rong, Yue Army Engn Univ PLA Coll Commun Engn Nanjing 210007 Jiangsu Peoples R China Curtin Univ Sch Elect Engn Comp & Math Sci Bentley WA 6102 Australia

In this paper, we consider precoding matrices optimization for a new two-hop amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay system, where in addition to forwarding the source signals, the relay node concurrently transmits its own signals to the destination node. Compared with conventional AF MIMO relay systems where the relay node only forwards the source signals, the transceiver optimization problem in the new system is more challenging to solve. We prove that for all Schur-concave objective functions, the optimal source and relay matrices jointly diagonalize the source-relay-destination and relay-destination channels, which simplifies the matrices optimization problem to a joint subchannel and power allocation problem with scalar variables. It is shown that to achieve a maximal sum mutual information (MI) of both the source and relay links, the strongest subchannels of the second-hop channel should be allocated for transmitting signals from the relay node. With additional quality-of-service constraints in terms of the lower bounds of the MI of both links, the optimal subchannel allocation problem is NP-hard. In this case, we propose a suboptimal channel allocation algorithm with a low computational complexity. For a given subchannel allocation, we develop a primal decomposition based algorithm to efficiently solve the power allocation problem. Simulation results show that compared with the exhaustive search based channel allocation approach and the general nonlinear programming based power allocation algorithm, the proposed subchannel and power allocation algorithms have a much lower computational complexity with only a small performance loss.

关键词： Amplify-and-forward MIMO relay power allocation precoding matrix quality-of-service subchannel allocation

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Multimode basis selection for spatial multiplexing with limited feedback

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ELECTRONICS LETTERS 2005年第24期41卷 1340-1342页

作者： Mun, C Han, JK Kim, DH ChungJu Natl Univ Dept Elect Commun Engn Chungbuk 380702 South Korea Samsung Elect Telecommun R&D Ctr Suwon 442742 South Korea

Proposed is multimode basis selection in which the active bases are selected at the receiver from the common unitary basis set known at both receiving and transmitting ends, conveyed to the transmitter using limited feedback, and assembled into a precoding matrix at the transmitter. It is shown that the proposed multimode basis selection scheme outperforms both multimode antenna selection and Grassmannian multimode precoding in capacity in correlated fading channels without additional complexity and feedback.

关键词： spatial multiplexing receivers Communication switching precoding transmitters multimode basis selection fading channels radio transmitters multiplexing feedback limited feedback radio receivers precoding matrix Radio links and equipment

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1.7/2.6 GHz high-efficiency concurrent dual-band power amplifier with dual-band harmonic wave controlled transformer

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ELECTRONICS LETTERS 2014年第3期50卷 184-185页

作者： Chen, Peng He, Songbai Wang, Xianfei Dai, Zhijiang Univ Elect Sci & Technol China Sch Elect Engn Chengdu 611731 Peoples R China

A 1.7/2.6 GHz high-efficiency concurrent dual-band power amplifier (DBPA) with a dual-band harmonic wave controlled transformer is demonstrated. The proposed dual-band transformer, which transfers the fundamental and the second harmonic impedances of each frequency, is directly transmission line implemented with the help of an optimisation algorithm. The measurement results show that the proposed DBPA has performances of 70 and 64% power added efficiency with an 11 dB gain and a 41 dBm output power at 1.7 and 2.6 GHz, respectively. Its average drain efficiency is more than 42% and the adjacent channel leakage ratios are lower than -46 dBc at both frequencies with the digital predistortion adjustment for a 5 MHz WCDMA signal input.

关键词： channel coding channel estimation iterative decoding matrix algebra OFDM modulation precoding vectors channel estimation symbol detection OFDM system data-nulling superimposed pilot scheme input data vector precoding matrix training pilot insertion frequency-division multiplexed pilot FDM pilot input data distortion mitigation simple iterative reconstruction scheme

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Spread Spectrum OFDM-IM With Efficient Precoded matrix and Low Complexity Detector

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IEEE ACCESS 2024年 12卷 192293-192300页

作者： Waheed, Ahmed Mohammady, Somayeh Technol Univ Dublin TUD Sch Elect & Elect Engn Dublin 7 Ireland

This paper introduces a novel scheme that employs efficient precoded matrices for index modulation orthogonal frequency division multiplexing namely (EP-OFDM-IM). This technique implements Discrete Fourier Transform (DFT) and Fast Walsh Hadamard Transform (FWHT) precoded matrices for spreading the subset of active M-ary data symbols and their indices to transmit additional information. This aims to enhance the system's transmit diversity (TD) by exploiting multipath and index diversities. Moreover, a low complex minimum means square error greedy detector (MMSE-GD) is proposed that can achieve optimal performance for perfect channel state information (CSI) and superior performance compared to maximum likelihood (ML) under imperfect CSI. The theoretical analysis based on pair-wise error probability is derived to estimate the bit error probability (BEP) of the proposed scheme for the performance analysis. Simulation results demonstrate that our proposed scheme EP-OFDM-IM significantly outperforms various existing competitive benchmark IM schemes. Specifically, at a spectral efficiency (SE) of 1.5 bps/Hz, and BEP of 10-3, our proposed scheme achieves addition of 15dB gain.

关键词： Discrete Fourier transforms OFDM Indexes Computational complexity Detectors Symbols precoding Modulation Vectors Diversity methods Index modulation precoding matrix maximum likelihood greedy detector MMSE Walsh-Hadamard fast Walsh-Hadamard transform discrete Fourier transform 5G 6G

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A SVD-Based Optimum Algorithm Research for Macro-Femto Cell Interference Coordination 81

A SVD-Based Optimum Algorithm Research for Macro-Femto Cell ...

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81st IEEE Vehicular Technology Conference (VTC Spring)

作者： Yan, Kaiyue Yang, Yan Dang, Shuping Beijing Jiaotong Univ State Key Lab Rail Traff Control & Safety Beijing 100044 Peoples R China Univ Oxford Dept Engn Sci Oxford OX1 3PJ England

ISBN: (纸本)9781479980888

The intra-tier interference in heterogeneous networks becomes more serious when the number of macro-femto cells dramatically increases. Based on the singular value decomposition (SVD) algorithm, this paper proposes an optimized interference alignment (IA) algorithm to improve the macrofemto cell downlink rate. To achieve the largest degrees of freedom (DOF), we adopt the precoding matrix as a powerful tool to mitigate the effect of inter-channel interference (ICI). In comparison with the conventional interference coordination methods, the SVD algorithm is capable of adjusting the coefficients of the precoding matrix with lower complexity. Furthermore, zero-forcing algorithm is also used to combat ICI in this proposed IA algorithm. The numerical results show that ICI can be suppressed effectively and the system performance in terms of throughput and signal-to-interference-plus-noise ratio (SINR) can be improved considerably.

关键词： Heterogeneous network macro-femto cell interference alignment singular value decomposition precoding matrix

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Amplify-and-forward secondary spectrum access in multicarrier cognitive radio systems 3

Amplify-and-forward secondary spectrum access in multicarrie...

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IEEE International Workshop on Measurements and Networking (M&N)

作者： Darsena, Donatella Gelli, Giacinto Verde, Francesco Univ Parthenope Dipartimento Ingn Naples Italy Univ Federico II Dipartimento Ingn Elettr & Tecnol Informaz Naples Italy

ISBN: (纸本)9781479918607

Innovative spectrum sharing policies, possibly leveraged by cognitive radio (CR) technologies, are expected to play a significant role in forthcoming 5G systems, employing multicarrier techniques for modulation and multiple-access. In this paper, we propose an opportunistic amplify-and-forward relaying scheme for a multicarrier CR network, where a secondary user (SU) is allowed to share communication resources with a primary user (PU) transmitting with orthogonal frequency-division multiplexing (OFDM) technology. Instead of minimizing the interference to the PU, the SU transmitter relays the received PU signal on the different OFDM subcarriers by using a precoding matrix depending on the symbols that must be delivered to the SU receiver. The information-theoretic capacity of the proposed protocol is assessed, showing that, under mild conditions, the SU can gain a significant data-rate performance, while not degrading (but even improving) the PU performance.

关键词： 5G mobile communication OFDM modulation amplify and forward communication cognitive radio frequency division multiple access matrix algebra network coding precoding protocols radio receivers radio spectrum management radio transmitters relay networks (telecommunication) 5G system OFDM multiple access OFDM subcarrier amplify-and-forward secondary spectrum access communication resources share innovative spectrum sharing policy multicarrier cognitive radio system opportunistic amplify-and-forward relaying scheme orthogonal frequency-division multiplexing technology precoding matrix primary user protocol information-theoretic capacity secondary user receiver secondary user transmitter relay Correlation Discrete Fourier transforms Frequency-domain analysis OFDM Receivers Training Orthogonal frequency division multiplexing Frequency division multiaccess Cognitive radio Radio spectrum management discrete Fourier transform Frequency-domain analysis prediction coding radio receivers matrix algebra RADIO TRANSMITTERS Receivers Network coding protocols Functional training Plutonium

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Stochastic precoding for MISO Interference Channels with Channel Mean Feedback

Stochastic Precoding for MISO Interference Channels with Cha...

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54th Annual IEEE Global Telecommunications Conference (GLOBECOM)

作者： Ding, Minhua Zhang, Q. T. City Univ Hong Kong Dept Elect Engn Hong Kong Hong Kong Peoples R China

ISBN: (纸本)9781424492688

Two linear precoding strategies are investigated for multiple-input single-out (MISO) interference channels with channel mean feedback at transmitters. The interference at each receiver is treated as additive noise. The challenge here is that previous analysis with perfect channel state information (CSI) at transmitters does not apply. Based on stochastic ordering, the altruistic non-equilibrium stochastic zero forcing strategy is first proposed, generalizing traditional zero forcing which requires perfect CSI. Interestingly, the precoding matrices here are all rank-one as in traditional zero forcing. The competitive use of the common channel is also formulated as a strategic game. Different from the perfect CSI case, with channel mean feedback, infinitely many Nash equilibria exist in general, which are not necessarily rank-one. Comparisons of the above two precoding strategies reveal no overall dominance of one over the other, thereby establishing stochastic zero forcing as an appealing alternative to the prevailing Nash equilibrium strategies.

关键词： Interference channels Laplace equations MISO interference channels Nash equilibrium Receivers Transmitters Vectors additive noise altruistic nonequilibrium stochastic zero forcing strategy channel mean feedback channel state information game theory infinitely many Nash equilibria linear precoding strategy multiple-input single-out interference channel precoding precoding matrix radio receivers radio transmitters radiofrequency interference receiver stochastic ordering stochastic precoding stochastic processes strategic game transmitter wireless channels

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