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Achieving maximum bit rate in a cognitive radio network with physical layer network coding

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2018年第10期31卷 e3558-e3558页

作者： Khosroazad, Somayeh Abedi, Ali Neda, Naaser Univ Maine Elect & Comp Engn Dept Wireless Sensor Networks Lab WiSe Net Orono ME USA Univ Birjand Fac Elect & Comp Engn Birjand Iran

In this paper, the power allocation problem in a relay-assisted cognitive radio network (CRN) is considered where the secondary users exchange information in an interweave mode on the basis of physical layer network coding. In order to enhance the capacity of CRN, using multiple-input multiple-output and orthogonal frequency division multiplexing has become very popular in the literature. This paper goes one step further to improve the throughput of secondary users using physical layer network coding by drawing off the transmission time. The main goal is to maximize the capacity of CRN, while keeping the total interference imposed on the primary users under a certain threshold. An optimal solution to this power allocation problem with limited relay power constraint, due to the limited budget, is derived;however, because of the high complexity of this method, an efficient suboptimal solution is also proposed.

关键词： cognitive radio networks multiple-input multiple-output orthogonal frequency division multiplexing physical layer network coding power allocation

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Feasibility of Space-Division-multiplexed Transmission of IEEE 802.11 n/ac-Compliant Wireless MIMO Signals Over OM3 Multimode Fiber

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2018年第11期36卷 2076-2082页

作者： Lei, Yi Li, Jianqiang Meng, Ziyi Wu, Rui Wan, Zhiquan Fan, Yuting Zhang, Wenjia Yin, Feifei Dai, Yitang Xu, Kun Beijing Univ Posts & Telecommun State Key Lab Informat Photon & Opt Commun Inst Informat Photon & Opt Commun Beijing 100876 Peoples R China Shanghai Jiao Tong Univ State Key Lab Adv Opt Commun Syst & Networks Shanghai 200240 Peoples R China

In this paper, we have experimentally demonstrated the feasibility of space-division-multiplexed 3 x 3 multiple-input multiple-output (MIMO) transmission over a single OM3 multimode fiber (MMF) using commercial IEEE 802.11 n/ac access points. Throughput performance for different fiber length links under a range of fiber bending conditions was evaluated. To study the throughput improvement by MIMO technology, throughput performance of single-input single-output (SISO), 2 x 2 MIMO and 3x3MIMO over separate SMF links was also measured for comparison. It is shown that, spatially-multiplexed MMF channel with 3x3MIMO configuration could provide a significant throughput increase in comparison with SISO and 2x2MIMO SMFs configurations, and present a comparable performance with 3x3MIMO SMFs configuration. Meanwhile, the analyses of the impact of fiber bending indicate that, even under a tight fiber bending radius as low as 2 mm, the system performance could still keep at an acceptable level. With all fiber bending radii tested, within each 5-min measurement time, the fiber channel is found to be good enough to provide throughput greater than twice the average SISO value for more than 87.66% and 72.72% of the time, at the 2.4 and 5 GHz bands, respectively. These results together point out a very simple and cost-saving solution for future in-building DASs to distribute wireless MIMO signals using commercially-availableMMFinfrastructure by space division multiplexing technique, even though it may encounter tight bending conditions.

关键词： Multimode fiber multiple-input multiple-output radio-over-fiber space-division-multiplexing

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Efficient Sphere Decoding Based on a Regular Detection Tree for Generalized Spatial Modulation MIMO Systems

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IEICE TRANSACTIONS ON COMMUNICATIONS 2018年第1期E101B卷 223-231页

作者： Yoon, Hye-Yeon Lee, Gwang-Ho Kim, Tae-Hwan Korea Aerosp Univ Sch Elect & Informat Engn 76 Hanggongdaehak Ro Goyang Si Gyeonggi Do South Korea

The generalized spatial modulation (GSM) is a new transmission technique that can realize high-performance multiple-input multiple-output (MIMO) communication systems with a low RF complexity. This paper presents an efficient sphere decoding method used to perform the symbol detection for the generalized spatial modulation (GSM) multiple-input multiple-output (MIMO) systems. In the proposed method, the cost metric is modified so that it does not include the cancellation of the nonexistent interference. The modified cost metric can be computed by formulating a detection tree that has a regular structure representing the transmit antenna combinations as well as the symbol vectors, both of which are detected efficiently by finding the shortest path on the basis of an efficient tree search algorithm. As the tree search algorithm is performed for the regular detection tree to compute the modified but mathematically-equivalent cost metric, the efficiency of the sphere decoding is improved while the biterror rate performance is not degraded. The simulation results show that the proposed method reduces the complexity significantly when compared with the previous method: for the 6 +/- 6 64QAM GSM-MIMO system with two active antennas, the average reduction rate of the complexity is as high as 45.8% in the count of the numerical operations.

关键词： multiple-input multiple-output generalized spatial modulation sphere decoding symbol detection maximum likelihood

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Performance analysis for low-complexity detection of MIMO V2V communication systems

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COMPUTER NETWORKS 2018年 140卷 92-100页

作者： Li, Guoquan Zhou, Ying Bai, Tong Lin, Jinzhao Pang, Yu Wu, Wei Din, Sadia Jeon, Gwanggil Chongqing Univ Posts & Telecommun Chongqing Peoples R China Sichuan Univ Chengdu Sichuan Peoples R China Kyungpook Natl Univ Sch Comp Sci & Engn Daegu South Korea Incheon Natl Univ Incheon South Korea

In Vehicle-to-Vehicle (V2V) communication, the rapid movement of vehicles brings fast attenuation of signal propagation and serious shift effect of Doppler frequency, leading to serious transmission performance deterioration. multiple-input multiple-output (MIMO) technique can be well applied in V2V communication by exploiting diversity and multiplexing gain to improve the system reliability and increase the data rate. In an MIMO system, the achieved diversity and multiplexing gain is closely related to its detection method. Integer-Forcing (IF) detection is one of the linear detections proposed in recent years. Compared to the traditional linear and Maximum Likelihood (ML) detection, IF has a good tradeoff between the complexity and system performance. In this paper, considering its good detection performance, IF is applied to the detection of a MIMO V2V communication system and the performance is further analyzed theoretically by employing Alamouti code at the transmitters. The diversity gain proves to be full and is confirmed by the simulation results. (C) 2018 Elsevier B.V. All rights reserved.

关键词： V2V communication multiple-input multiple-output Low-complexity detection Performance analysis

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Iterative Receivers for Downlink MIMO-SCMA: Message Passing and Distributed Cooperative Detection

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2018年第5期17卷 3444-3458页

作者： Yuan, Weijie Wu, Nan Guo, Qinghua Li, Yonghui Xing, Chengwen Kuang, Jingming Beijing Inst Technol Sch Informat & Elect Beijing 100081 Peoples R China Univ Wollongong Sch Elect Comp & Telecommun Engn Wollongong NSW 2522 Australia Univ Sydney Sch Elect & Informat Engn Ctr Excellence Telecommun Sydney NSW 2006 Australia

The rapid development of mobile communications requires even higher spectral efficiency. Non-orthogonal multiple access (NOMA) has emerged as a promising technology to further increase the access efficiency of wireless networks. Among several NOMA schemes, it has been shown that sparse code multiple access (SCMA) is able to achieve better performance. In this paper, we consider a downlink MIMO-SCMA system over frequency selective fading channels. For optimal detection, the complexity increases exponentially with the product of the number of users, the number of antennas and the channel length. To tackle this challenge, we propose near optimal low-complexity iterative receivers based on factor graph. By introducing auxiliary variables, a stretched factor graph is constructed and a hybrid belief propagation (BP) and expectation propagation (EP) receiver, named stretch-BP-EP, is proposed. Considering the convergence problem of BP algorithm on loopy factor graph, we convexify the Bethe free energy and propose a convergence-guaranteed BP-EP receiver, named conv-BP-EP. We further consider cooperative network and propose two distributed cooperative detection schemes to exploit the diversity gain, namely, belief consensus-based algorithm and the Bregman alternative direction method of multipliers (ADMM)-based method. Simulation results verify the superior performance of the proposed conv-BP-EP receiver compared with other methods. The two proposed distributed cooperative detection schemes can improve the bit error rate performance by exploiting the diversity gain. Moreover, Bregman ADMM method outperforms the belief consensus-based algorithm in noisy inter-user links.

关键词： Sparse code multiple access multiple-input multiple-output belief propagation expectation propagation variational free energy distributed cooperative detection

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Antenna Diversity for Downlink MIMO-NOMA Systems With Partial Channel State Information

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IEEE COMMUNICATIONS LETTERS 2018年第10期22卷 2172-2175页

作者： Gong, Ming-yan Yang, Zhen Lyu, Bin Nanjing Univ Posts & Telecommun Key Lab Broadband Wireless Commun & Sensor Networ Minist Educ Nanjing 210003 Jiangsu Peoples R China

In this letter, antenna diversity is used to improve the outage performance of downlink multiple-input multiple-output non-orthogonal multiple access systems with partial channel state information, of which the transmitter only knows the distance and channel direction information associated with each user. We analyze the ergodic rate and the outage probability of the proposed system. Moreover, we derive the closed-form expression of each user's outage probability. Numerical results confirm the accuracy of our analysis.

关键词： Antenna diversity multiple-input multiple-output non-orthogonal multiple access partial channel state information

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Multi-Dimensional Space-Time Shift Keying for Wireless Communications

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IEEE ACCESS 2019年 7卷 135801-135811页

作者： Zheng, Guangtao Jiang, Ming Sun Yat Sen Univ Sch Elect & Informat Technol Guangzhou 510275 Peoples R China Univ Virginia Dept Comp Sci Charlottesville VA 22903 USA

In this paper, we introduce the concept of multi-dimensional (MD) space-time shift keying (STSK) for improving conventional STSK schemes, while still maintaining the general STSK structure for backward compatibility. Firstly, we design two transmission modes for three-dimensional (3-D) STSK schemes, referred to as R2 3-D STSK and R3 3-D STSK, with the incorporation of 3-D constellations. In addition, we devise a joint optimization mechanism utilizing the modified simplified conjugate gradient (SCG) algorithm to enhance the achievable system performance of R3 3-D STSK, through a harmonized design of the constellation and the dispersion matrix set. Furthermore, we derive the optimal combinations of the 3-D constellation coordinates for R2 3-D STSK by maximizing the minimal determinant of the difference matrices. Then, we extend 3-D STSK to the MD STSK family, offering a flexible and efficient performance enhancement mechanism for STSK systems. Extensive simulation results are provided to show the tradeoffs among link performance, diversity order and signal dimensionality of the proposed MD STSK scheme, illustrating a good way to upgrade conventional STSK systems.

关键词： Optimization Wireless communication Dispersion MIMO communication Research and development Simulation Modulation Coordinate combination joint optimization multi-dimensional constellation multiple-input multiple-output space-time shift keying

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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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Sixty Years of Coherent Versus Non-Coherent Tradeoffs and the Road From 5G to Wireless Futures

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IEEE ACCESS 2019年 7卷 178246-178299页

作者： Xu, Chao Ishikawa, Naoki Rajashekar, Rakshith Sugiura, Shinya Maunder, Robert G. Wang, Zhaocheng Yang, Lie-Liang Hanzo, Lajos Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England Hiroshima City Univ Grad Sch Informat Sci Hiroshima 7313194 Japan Univ Tokyo Inst Ind Sci Tokyo 1538505 Japan Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China

Sixty years of coherent versus non-coherent tradeoff as well as the twenty years of coherent versus non-coherent tradeoff in multiple-input multiple-output (MIMO) systems are surveyed. Furthermore, the advantages of adaptivity are discussed. More explicitly, in order to support the diverse communication requirements of different applications in a unified platform, the 5G New Radio (NR) offers unprecendented adaptivity, abeit at the cost of a substantial amount of signalling overhead that consumes both power and the valuable spectral resources. Striking a beneficial coherent versus non-coherent tradeoff is capable of reducing the pilot overheads of channel estimation, whilst relying on low-complexity detectors, especially in high-mobility scenarios. Furthermore, since energy-efficiency is of salient importance both in the operational and future networks, following the powerful Index Modulation (IM) pholosophy, we conceive a holistic adaptive pholosophy striking the most appropriate coherent/non-coherent, single-/multiple-antenna and diversity/multiplexing tradeoffs, where the number of RF chains, the Peak-to-Average Power Ratio (PAPR) of signal transmission and the maximum amount of interference tolerated by signal detection are all taken into account. We demonstrate that this intelligent tripple-fold adaptivity offers significant benefits in next-generation applications of mmWave and Terahertz solutions, in space-air-ground integrated networks, in full-duplex techniques and in other sophisticated channel coding assisted system designs, where powerful machine learning algorithms are expected to make autonomous decisions concerning the best mode of operation with minimal human intervention.

关键词： Coherent channel estimation non-coherent differential encoding sphere decoding decision-feedback multiple-input multiple-output differential space-time modulation energy-efficiency index modulation peak-to-average power ratio 5G New Radio millimeter wave physical layer link budget 6G Terahertz space-air-ground full-duplex channel coding machine learning artificial intelligence

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A Comparative Analysis of Deterministic Detection and Estimation Techniques for MIMO SFCW Radars

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IEEE ACCESS 2019年 7卷 129848-129861页

作者： Sirignano, Emilio Davoli, Alessandro Vitetta, Giorgio M. Viappiani, Federico Univ Modena & Reggio Emilia Dept Engn Enzo Ferrari I-41125 Modena Italy

In this paper, the problem of the joint estimation of the range and azimuth of multiple targets in a multiple-input multiple-output stepped-frequency continuous wave radar system is investigated. Three deterministic algorithms solving it through an iterative beam cancellation procedure are described;moreover, an iterative technique, based on the expectation-maximization algorithm, is developed with the aim of reflning their estimates. The accuracy achieved by all the considered algorithms is assessed on the basis of the raw data acquired from a low power wideband radar device. Our results evidence that these algorithms achieve similar accuracies, but at the price of different computational efforts.

关键词： Beamforming direction of arrival multiple-input multiple-output radar signal processing stepped-frequency continuous-wave

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