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An Efficient Relay Selection and Power Allocation Schemes for Cognitive MIMO DF Relay Networks with Buffers

ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2017年第7期42卷 2839-2849页

作者： Al-Eryani, Yasser F. Salhab, Anas M. Zummo, Salam A. King Fahd Univ Petr & Minerals Dept Elect Engn Dhahran 31261 Saudi Arabia

In this paper, decode-and-forward buffer-aided opportunistic relay selection and antenna transmission power allocation for underlay cognitive radio are considered. All the transmitting and receiving nodes are assumed to be equipped with multiple antennas resulting in a multiple-input multiple-output (MIMO) system. First, a low-complexity MIMO-based relay selection scheme that maximizes the single-hop normalized sum rate of the primary network (PN) and secondary network (SN) is proposed. Second, a sub-optimal antenna transmission power allocation scheme that maximizes the normalized sum rate of the PN and SN is proposed. For power optimization, first, optimal expressions for antenna transmission power of both the PN and SN nodes are derived separately. The derived expressions are then used in an iterative algorithm to produce a near-optimum solution that maximizes the normalized sum rate per time slot. Simulation results are provided to evaluate the performance of the proposed MIMO-based relay selection and antenna transmission power allocation schemes and compare their performance with that of the optimal scenario. The findings show that the proposed relay selection and antenna transmission power allocation schemes introduce a satisfactory performance with much lower complexity compared to the optimal schemes. Additionally, results show that using a buffer-aided relaying significantly enhances the SN performance while slightly deteriorates the performance of the PN.

关键词： Cognitive radio Decode-and-forward Buffer-aided multiple-input multiple-output Convex optimization Iterative algorithm

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Reinforcement Learning-Based Joint User Pairing and Power Allocation in MIMO-NOMA Systems

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SENSORS 2020年第24期20卷 7094-7094页

作者： Lee, Jaehee So, Jaewoo Sogang Univ Dept Elect Engn Seoul 04107 South Korea

In this paper, we consider a multiple-input multiple-output (MIMO)-non-orthogonal multiple access (NOMA) system with reinforcement learning (RL). NOMA, which is a technique for increasing the spectrum efficiency, has been extensively studied in fifth-generation (5G) wireless communication systems. The application of MIMO to NOMA can result in an even higher spectral efficiency. Moreover, user pairing and power allocation problem are important techniques in NOMA. However, NOMA has a fundamental limitation of the high computational complexity due to rapidly changing radio channels. This limitation makes it difficult to utilize the characteristics of the channel and allocate radio resources efficiently. To reduce the computational complexity, we propose an RL-based joint user pairing and power allocation scheme. By applying Q-learning, we are able to perform user pairing and power allocation simultaneously, which reduces the computational complexity. The simulation results show that the proposed scheme achieves a sum rate similar to that achieved with the exhaustive search (ES).

关键词： non-orthogonal multiple access multiple-input multiple-output user pairing power allocation reinforcement learning

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Pair-wise error probability and its Chernoff upper bound for unitary space-time code

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Science China(Information Sciences) 2010年第8期53卷 1613-1621页

作者： ZHANG DaPeng 1,2 , LIU Ju 1 , XU HongJi 1 & JI Hui 1 1 School of Information Science and Engineering, Shandong University, Jinan 250100, China 2 State Key Laboratory of Integrated Services Networks, Xidian University, Xi’an 710071, China 1. School of Information Science and Engineering Shandong University Jinan 250100 China2. State Key Laboratory of Integrated Services Networks Xidian University Xi’an 710071 China

Unitary space-time code is ideally suited for rapid fading scenarios as it can operate well without channel state information (CSI), which is of vital significance for improving the effectivity and reliability of wireless communication systems. Pair-wise error probability (PEP) is an important factor for studying the reliability of a communication system. However, the existing scheme only gives the final result of PEP and the corresponding Chernoff upper bound (CUB) is obtained through magnification, which is not of universal significance for this kind of problems. In this paper, we employ the log-likelihood ratio of probability density functions of the received signals conditioned on the two possibly transmitted signals and by virtue of moment generating function we give the details in deriving the final precise residue expression for PEP and its CUB. At last, we verify the above results by simulations.

关键词： multiple-input multiple-output space-time code unitary space-time code pair-wise error probability Chernoff upper bound

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Signalling scheme for achieving dynamic degrees of freedom in MIMO Y channel

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INTERNATIONAL JOURNAL OF GRID AND UTILITY COMPUTING 2014年第3期5卷 149-155页

作者： Wang, Yong Guo, Aixiang He, Hong Li, Hui Li, Fengrong Xidian Univ State Key Lab Integrated Serv Networks Xian Shaanxi Peoples R China Chinese Acad Sci Shanghai Inst Microsyst & Informat Technol Key Lab Wireless Sensor Network & Commun Shanghai 200050 Peoples R China

The multiple input and multiple output (MIMO) Y channel is a generalised channel model of the two-way relay channel, which supports point-to-multipoint traffic pattern for unicast. In this paper, a signalling scheme for achieving dynamic Degrees of Freedom (DOF) in the MIMO Y channel is proposed where each user exchanges d pairs of messages with each of the other users simultaneously via an intermediate relay and d is a variable integer. To complete this scheme, two novel signalling techniques are utilised, which are Signal Space Alignment for Network Coding (SSA-NC) and interference nulling beamforming combined with Receiving Antenna Selection (RAS) technique. Dynamic DOF can be obtained by changing d, e.g., more diversity gain can be obtained if d is small, while more DOF can be achieved if d becomes larger.

关键词： MIMO multiple-input multiple-output network coding utility computing degrees of freedom signal space alignment

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Product manifold optimization-based joint beamforming for RIS-aided MIMO systems: A fairness based approach

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ICT EXPRESS 2024年第5期10卷 1110-1116页

作者： Ji, Xiang Song, Yunchao Liu, Chen Huang, Zheng Qian, Mujun Nanjing Univ Posts & Telecommun Coll Elect & Opt Engn Coll Flexible Elect Future Technol Nanjing Peoples R China

Reconfigurable intelligent Surface (RIS) can effectively improve the communication quality and extend the signal coverage range by reconfiguring the wireless communication transmission environment, which is very suitable for millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems. In this paper, a product manifold optimization-based beamforming design (PMO-BD) algorithm for a RIS-assisted multi-user MIMO system is proposed to enhance fairness among users. We establish a lower bound for the minimum signal-tointerference-plus-noise ratio (SINR) among users as the optimization objective, which is subjected to multiple constraints. By maximizing the lower bound to ensure the quality of service (QoS) for each user, fairness among users get improved. The PMO-BD algorithm exploits the internal structure of the product manifold to deal with the high dimension and nonlinear characteristics of the problem effectively, thereby reducing algorithm complexity and enhancing convergence rates. Simulation results verify the advantages of the proposed PMO-BD algorithm in comparison to other algorithms. (c) 2024 The Author(s). Published by Elsevier B.V. on behalf of The Korean Institute of Communications and Information Sciences. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).

关键词： Reconfigurable intelligent surface multiple-input multiple-output Beamforming Product manifold optimization

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Unified Performance Analysis of Antenna Selection Schemes for Cooperative MIMO-NOMA With Practical Impairments

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2022年第6期21卷 4364-4378页

作者： Aldababsa, Mahmoud Guven, Eray Durmaz, M. Akif Goztepe, Caner Kurt, Gunes Karabulut Kucur, Oguz Istanbul Gelisim Univ Dept Elect & Elect Engn TR-34310 Istanbul Turkey Istanbul Tech Univ Dept Elect & Commun Engn TR-34469 Istanbul Turkey Turkcell Technol 5G Res & Dev Team TR-34854 Istanbul Turkey Polytech Montreal Dept Elect Engn Polygrames Res Ctr Montreal PQ H3T 1J4 Canada Gebze Tech Univ Dept Elect Engn TR-41400 Gebze Turkey

This paper presents a unified outage probability (OP) performance analysis of two hybrid antenna selection (AS) schemes, transmit antenna selection (TAS) and maximal ratio combining (MRC), and joint transmit and receive antenna selection (JTRAS) in multiple-input multiple-output non-orthogonal multiple access based downlink amplify-and-forward (AF) relaying network with channel estimation error (CEE) and feedback delay (FD). Since the communications in the first and second hops are kinds of single-user and multi-user communications, respectively the AS is done as optimal TAS/MRC or JTRAS is applied in the first hop while the suboptimal majority-based TAS/MRC or JTRAS is employed in the second hop. For both TAS/MRC and JTRAS schemes, the OP expressions are derived in single closed-form over Nakagami-m fading channels in the practical and ideal cases. Moreover, in the practical case, the lower bound OP expressions are found and at high signal-to-noise ratio (SNR) values, the OP reaches an error floor value, which means zero-diversity order. In the ideal case, asymptotic OP expressions are obtained in high SNR regime and demonstrate achievable non-zero diversity and array gains. Finally, through simulations and software-defined radio-based real-time tests, the accuracy of theoretical analysis is validated.

关键词： Outage probability transmit antenna selection maximal ratio combining joint transmit and receive antenna selection multiple-input multiple-output non-orthogonal multiple access channel estimation error feedback delay software-defined radio-based real-time tests

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Multiuser MIMO OFDM Based TDD/TDMA for Next Generation Wireless Communication Systems

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WIRELESS PERSONAL COMMUNICATIONS 2010年第2期52卷 289-324页

作者： Lu Zhaogan Rao Yuan Zhang Taiyi Wang Liejun Xi An Jiao Tong Univ Sch Elect & Informat Engn Xian 710049 Peoples R China Xi An Jiao Tong Univ Software Engn Sch Xian 710049 Peoples R China

multiple-input multiple-output (MIMO) wireless technology in combination with orthogonal frequency division multiplexing (MIMO OFDM) is an attractive air-interface solution for next-generation wireless local area networks (WLANs), wireless metropolitan area networks (WMANs), and fourth-generation mobile cellular wireless systems. In this paper, one multiuser MIMO OFDM systems with TDD/TDMA was proposed for next-generation wireless mobile communications, i.e., TDD/TDMA 4G, which can avoid or alleviate the specific limitations of existing techniques designed for multiuser MIMO OFDM systems in broadband wireless mobile channel scenarios, i.e., bad performance and extreme complexity of multiuser detectors for rank-deficient multiuser MIMO OFDM systems with CDMA as access modes, extreme challenges of spatial MIMO channel estimators in rank-deficient MIMO OFDM systems, and exponential growth complexity of optimal sub-carrier allocations for OFDMA-based MIMO OFDM systems. Furthermore, inspired from the Steiner channel estimation method in multi-user CDMA uplink wireless channels, we proposed a new design scheme of training sequence in time domain to conduct channel estimation. Training sequences of different transmit antennas can be simply obtained by truncating the circular extension of one basic training sequence, and the pilot matrix assembled by these training sequences is one circular matrix with good reversibility. A novel eigenmode transmission was also given in this paper, and data symbols encoded by space-time codes can be steered to these eigenmodes similar to MIMO wireless communication systems with single-carrier transmission. At the same time,, an improved water-filling scheme was also described for determining the optimal transmit powers for orthogonal eigenmodes. The classical water-filling strategy is firstly adopted to determine the optimal power allocation and correspondent bit numbers for every eigenmode, followed by a residual power reallocation to furt

关键词： multiple-input multiple-output Orthogonal frequency division multiplexing Multiuser diversity Link adaptation Channel estimation

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MIMO Assisted Networks Relying on Intelligent Reflective Surfaces: A Stochastic Geometry Based Analysis

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2022年第1期71卷 571-582页

作者： Hou, Tianwei Liu, Yuanwei Song, Zhengyu Sun, Xin Chen, Yue Hanzo, Lajos Beijing Jiaotong Univ Sch Elect & Informat Engn Beijing 100044 Peoples R China Queen Mary Univ London Sch Elect Engn & Comp Sci London E1 4NS England Univ Southampton Southampton SO17 1BJ Hants England

Intelligent reflective surfaces (IRSs) are invoked for improving both the spectral efficiency (SE) and energy efficiency (EE). Specifically, an IRS-aided multiple-input multiple-output network is considered, where the performance of randomly roaming users is analyzed by utilizing stochastic geometry tools. As such, to distinguish the superposed signals at each user, the passive beamforming weight at the IRSs and detection weight vectors at the users are jointly designed. As a benefit, by adopting a zero-forcing-based design, the intra-cell interference imposed by the IRS can be suppressed. In order to evaluate the performance of the proposed network, we first derive the approximated channel statistics in the high signal-to-noise-ratio (SNR) regime. Then, we derive the closed-form expressions both for the outage probability and for the ergodic rate of users. Both the high-SNR slopes of ergodic rate and the diversity orders of outage probability are derived for gleaning further insights. The network's SE and EE are also derived. Our numerical results are provided to confirm that: i) the high-SNR slope of the proposed network is one;ii) the SE and EE can be significantly enhanced by increasing the number of IRS elements.

关键词： Array signal processing Signal to noise ratio Geometry Probability density function Power system reliability Interference Tools Intelligent reflective surfaces (IRS) multiple-input multiple-output passive beamforming stochastic geometry

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Joint Source-Relay Precoding and Power Allocation for Secure Amplify-and-Forward MIMO Relay Networks

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IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY 2014年第8期9卷 1240-1250页

作者： Wang, Hui-Ming Liu, Feng Xia, Xiang-Gen Xi An Jiao Tong Univ Sch Elect & Informat Engn Minist Educ Key Lab Intelligent Networks & Network Secur Xian 710049 Peoples R China Xidian Univ Inst Elect Xian 710049 Peoples R China Univ Delaware Dept Elect & Comp Engn Newark DE 19716 USA

In this paper, we investigate the security issue of a two-hop amplify-and-forward multiple-input multiple-output wireless relay network in the existence of a multiantenna eavesdropper. The optimal scheme to achieve the secrecy capacity involves a nonconvex optimization and is still an open problem. Aiming to find an efficient way to enhance the secrecy rate with a tractable complexity, we propose a suboptimal joint source and relay linear precoding and power allocation scheme. In the scheme, the source node adopts a generalized singular value decomposition (SVD)-based precoding to transmit the signal in the first phase, and the relay node forwards the received signal based on the SVD precoding in the null-space of the wiretap channel in the second phase. Power allocations in both phases are optimized to maximize the secrecy rate by an alternating iterative optimization algorithm. Each iteration involves two subproblems. One has a water-filling solution and the other has a closed-form solution or a water-filling-like solution as well, both of which are computationally very efficient. The iteration converges fast and we prove that it guarantees to find a stationary optimum. Furthermore, we show that when the eavesdropper has equal or more antennas than the source does, the secrecy rate is a quasi-concave function of the source power so that allocating all the source power is generally not optimal. Numerical evaluation results are provided to show the effectiveness of the iterative algorithm and the proposed secrecy scheme.

关键词： Physical layer security secrecy rate relay multiple-input multiple-output precoding generalized singular value decomposition

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Array Gain Analysis in Molecular MIMO Communications

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IEEE ACCESS 2018年 6卷 61091-61102页

作者： Damrath, Martin Yilmaz, H. Birkan Chae, Chan-Byoung Hoeher, Peter Adam Univ Kiel Fac Engn D-24143 Kiel Germany Yonsei Univ Sch Integrated Technol Yonsei Inst Convergence Technol Incheon 406840 South Korea

In this paper, spatial transmission techniques in the area of multiple-input multiple-output (MIMO) diffusion-based molecular communications (DBMC) are investigated. For transmitter-side spatial coding, Alamouti-type coding and repetition MIMO coding are analyzed. At the receiver-side, selection diversity and equal-gain combining are studied as combining strategies. Throughout the numerical analysis, a symmetrical 2 x 2 MIMO-DBMC system is assumed. Furthermore, a trained artificial neural network is utilized to acquire the channel impulse responses. The numerical analysis demonstrates that there is no spatial diversity gain in the DBMC system under investigation, but that it is possible to achieve an array gain instead. In addition, it is shown that for MIMO-DBMC systems repetition MIMO coding is superior to Alamouti-type coding.

关键词： Array gain artificial neural network channel modeling molecular communication via diffusion multiple-input multiple-output spatial diversity

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