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SWORD: Towards a Soft and Open Radio Design for Rapid Development, Profiling, Validation and Testing

IEEE ACCESS 2019年 7卷 186017-186040页

作者： Georgis, Georgios Filo, Marcin Thanos, Alexios Husmann, Christopher Ducoing, J. C. De Luna Tafazolli, Rahim Nikitopoulos, Konstantinos Univ Surrey Inst Commun Syst 5G Innovat Ctr Wireless Syst Lab Guildford GU2 7XH Surrey England

The vision, as we move to future wireless communication systems, embraces diverse qualities targeting significant enhancements from the spectrum, to user experience. Newly-defined air-interface features, such as large number of base station antennas and computationally complex physical layer approaches come with a non-trivial development effort, especially when scalability and flexibility need to be factored in. In addition, testing those features without commercial, off-the-shelf equipment has a high deployment, operational and maintenance cost. On one hand, industry-hardened solutions are inaccessible to the research community due to restrictive legal and financial licensing. On the other hand, research-grade real-time solutions are either lacking versatility, modularity and a complete protocol stack, or, for those that are full-stack and modular, only the most elementary transmission modes are on offer (e.g., very low number of base station antennas). Aiming to address these shortcomings towards an ideal research platform, this paper presents SWORD, a SoftWare Open Radio Design that is flexible, open for research, low-cost, scalable and software-driven, able to support advanced large and massive multiple-input multiple-output (MIMO) approaches. Starting with just a single-input single-output air-interface and commercial off-the-shelf equipment, we create a software-intensive baseband platform that, together with an acceleration/profiling framework, can serve as a research-grade base station for exploring advancements towards future wireless systems and beyond.

关键词： Acceleration multiple-input multiple-output SIMD software-defined radios beamforming

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SYNCHRONIZATION SCHEMES FOR MIMO GENERALIZED FREQUENCY DIVISION multipleXING SYSTEMS

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电机工程学刊 2016年第6期23卷 215-220页

作者： Yao-Jen Liang Xuan-Ming Bai

With the increasing data rates and the requirement of less transmission delay, which cannot be satisfied by the fourth generation (4G) cellular systems, next generation or the fifth generation (5G) is expected to deal with these requirements. Among the promising techniques for 5G systems, generalized frequency division multiplexing (GFDM) would be a good candidate due to its flexibility of spectrum mapping, waveform generation, and cooperation of multiple antennas. In this work, we study the synchronization issues of carrier frequency offset (CFO) and sampling time offset (STO). Two methods of estimation of CFO and STO are proposed to combine the estimates at two receive antennas. Through simulation results, we demonstrate that MIMO technique could enhance the estimation accuracies of both CFO and STO.

关键词： generalized frequency division multiplexing carrier frequency offset sampling time offset multiple-input multiple-output estimate

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Developing the First mmWave Fully-Connected Hybrid Beamformer With a Large Antenna Array

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IEEE ACCESS 2020年 8卷 141282-141291页

作者： Payami, Sohail Khalily, Mohsen Araghi, Ali Loh, Tian Hong Cheadle, David Nikitopoulos, Konstantinos Tafazolli, Rahim Univ Surrey Inst Commun Syst Guildford GU2 7XS Surrey England Natl Phys Lab NPL 5G & Future Commun Technol Grp Teddington TW11 0LW Middx England

Millimeter wave (mmWave) systems with effective beamforming capability play a key role in fulfilling the high data-rate demands of current and future wireless technologies. Hybrid analog-to-digital beamformers have been identified as a cost-effective and energy-efficient solution towards deploying such systems. Most of the existing hybrid beamforming architectures rely on a subconnected phase shifter network with a large number of antennas. Such approaches, however, cannot fully exploit the advantages of large arrays. On the other hand, the current fully-connected beamformers accommodate only a small number of antennas, which substantially limits their beamforming capabilities. In this article, we present a mmWave hybrid beamformer testbed with a fully-connected network of phase shifters and adjustable attenuators and a large number of antenna elements. To our knowledge, this is the first platform that connects two RF inputs from the baseband to a 16 x 8 antenna array, and it operates at 26 GHz with a 2 GHz bandwidth. It provides a wide scanning range of 60 degrees, and the flexibility to control both the phase and the amplitude of the signals between each of the RF chains and antennas. This beamforming platform can be used in both short and long-range communications with linear equivalent isotropically radiated power (EIRP) variation between 10 dBm and 60 dBm. In this article, we present the design, calibration procedures and evaluations of such a complex system as well as discussions on the critical factors to consider for their practical implementation.

关键词： Millimeter wave multiple-input multiple-output fully-connected hybrid beamforming phased array antenna testbed

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A Low-Complexity Algorithm for a Reinforcement Learning-Based Channel Estimator for MIMO Systems

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SENSORS 2022年第12期22卷 4379-4379页

作者： Kim, Tae-Kyoung Min, Moonsik Gachon Univ Dept Elect Engn Seongnam 13120 South Korea Kyungpook Natl Univ Sch Elect Engn Daegu 41566 South Korea Kyungpook Natl Univ Sch Elect & Elect Engn Daegu 41566 South Korea

This paper proposes a low-complexity algorithm for a reinforcement learning-based channel estimator for multiple-input multiple-output systems. The proposed channel estimator utilizes detected symbols to reduce the channel estimation error. However, the detected data symbols may include errors at the receiver owing to the characteristics of the wireless channels. Thus, the detected data symbols are selectively used as additional pilot symbols. To this end, a Markov decision process (MDP) problem is defined to optimize the selection of the detected data symbols. Subsequently, a reinforcement learning algorithm is developed to solve the MDP problem with computational efficiency. The developed algorithm derives the optimal policy in a closed form by introducing backup samples and data subblocks, to reduce latency and complexity. Simulations are conducted, and the results show that the proposed channel estimator significantly reduces the minimum-mean square error of the channel estimates, thus improving the block error rate compared to the conventional channel estimation.

关键词： multiple-input multiple-output channel estimation Markov decision process reinforcement learning

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An electrically small 4-port self-decoupled MIMO antenna pairs operating in n78 5G NR band for smartphone applications

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2022年 145卷

作者： Moses, Abi T. Zerith Moses, Nesasudha Janapala, Doondi Kumar Karunya Inst Technol & Sci Dept Elect & Commun Engn Coimbatore India

In this article, a 4-port electrically small multiple-input multiple-output (MIMO) antenna system functioning in 5G n78 band for the future smartphone implementation is recommended. The system includes two antenna pairs that are positioned in the exact centers of the vertical edges of the smartphone system. The overall size of each antenna pair is only 23.5 x 5.2 mm2. The reduction is size is obtained by connecting the two radiators, and the antenna pair is excited by coaxial feeding technique. A very good and acceptable isolation amid the antenna elements are accomplished by inserting a T-shaped structure, and is further enhanced with the addition of a reflector at the backside of the radiator. The self-isolated MIMO system operates in the n78 sub-6 GHz band (3.4-3.6 GHz) of the 5G Frequency Range 1 (FR1), with worst case isolation of -17.5 dB between the antennas in the same block in the entire band of operation. The evolution analysis to acquire the proposed structure and parametric study of some ideal parameters are carried out to get a superior insight of the operating principle of the proposed structure. Various MIMO diversity parameters such as Envelope Correlation Coefficient (ECC), Channel Capacity Loss (CCL), Total Active Reflection Coefficient (TARC), Diversity Gain (DG), and Mean Effective Gain (MEG) of the MIMO system are measured and compared with the calculated values. The ECC value is <0.009 in the whole essential operating band, the poorest being between Ant.1 and Ant. 2. A model of the designed smartphone MIMO system is fabricated and experimentally verified, with acceptable coherence between the simulated and the measured results. The MIMO system has a total efficiency and peak gain over 74% and 4.53 dBi correspondingly in the complete operating bandwidth, making it a suitable contender for the future 5G smartphone application. Likewise, the effect of user hand on the S-Parameters and antenna pattern are studied and acceptable results are obtained

关键词： Self-decoupled multiple-input multiple-output Isolation Smartphone User-hand impact n78 band

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A Low-Complexity CLSIC-LMMSE-Based Multi-User Detection Algorithm for Coded MIMO Systems with High Order Modulation

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KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS 2017年第4期11卷 1954-1971页

作者： Xu, Jin Zhang, Kai Zhengzhou Univ Light Ind Sch Comp & Commun Engn Zhengzhou 450000 Peoples R China Beijing Univ Posts & Telecommun Sch Informat & Commun Engn Beijing 100876 Peoples R China

In this work, first, a multiuser detection (MUD) algorithm based on component-level soft interference cancellation and linear minimum mean square error (CLSIC-LMMSE) is proposed, which can enhance the bit error ratio (BER) performance of the traditional SIC-LMMSE-based MUD by mitigating error propagation. Second, for non-binary low density parity check (NB-LDPC) coded high-order modulation systems, when the proposed algorithm is integrated with partial mapping, the receiver with iterative detection and decoding (IDD) achieves not only better BER performance but also significantly computational complexity reduction over the traditional SIC-LMMSE-based IDD scheme. Extrinsic information transfer chart (EXIT) analysis and numerical simulations are both used to support the conclusions.

关键词： multiple-input multiple-output component-level soft interference cancellation non-binary LDPC iterative detection and decoding extrinsic information transfer chart

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Adaptive power permutation modulation: A novel transmission technique for increased spectral efficiency over fading channels

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2024年第3期37卷 e5667-e5667页

作者： Ozyurt, Serdar Ankara Yildirim Beyazit Univ Dept Elect & Elect Engn Ankara Turkiye

In this study, we propose a novel transmission technique for multiple-input multiple-output (MIMO) systems as a partial response to ever-growing demand for the increased spectral efficiency. The introduced scheme, called adaptive power permutation modulation (APPM), relies on the distinct power allocations on the conventionally modulated symbols to convey a certain number of additional information bits. Unlike the traditional power allocation strategies which generally aim to combat the channel fading and entail some form of channel state information (CSI) at the transmit side, APPM utilizes different power levels to convey additional information and does not necessitate any kind of CSI at the transmitter. The proposed approach is applied to two well-known MIMO configurations, Alamouti space-time block coding and zero-forcing beamforming, by embracing a general frequency-selective fading scenario under digital phase modulation. Both the modulation order and the power allocation levels on the modulated symbols are adaptively determined based on a set of additional information bits. It is shown that in addition to the conventionally modulated symbols, an extra sequence of N$$ N $$ bits can be conveyed without any significant additional complexity where N$$ N $$ equals the number of subcarriers. Also, it is demonstrated that considerable transmit power savings can be attained when compared with the standard schemes under a certain target spectral efficiency. By adopting a practical multiple-input multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) system model, it is demonstrated that the introduced scheme, termed as adaptive power permutation modulation (APPM), enables augmented spectral efficiency where as many additional information bits as the number of OFDM subcarriers can be conveyed. The application of APPM is illustrated for Alamouti and zero-forcing beamforming schemes under digital phase modulation. The presented design can also be used w

关键词： multiple-input multiple-output orthogonal frequency division multiplexing power allocation power permutation spectral efficiency

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DESIGN AND IMPLEMENTATION OF SYMBOL DETECTOR FOR MIMO SPATIAL multipleXING SYSTEMS

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JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS 2011年第4期20卷 727-739页

作者： Jung, Yunho Lee, Seongjoo Kim, Jaeseok Korea Aerosp Univ Sch Elect Telecommun & Comp Engn Goyang City 412791 South Korea Sejong Univ Dept Informat & Commun Engn Seoul 143747 South Korea Yonsei Univ Dept Elect & Elect Engn Seoul 120749 South Korea

In this paper, we propose an efficient symbol detection algorithm for multiple-input multiple-output spatial multiplexing (MIMO-SM) systems and present its design and implementation results. By enhancing the error performance of the first detected symbol that causes error propagation, the proposed algorithm achieves a considerable performance gain compared with the conventional sorted QR decomposition (SQRD) based detection and the ordered successive detection (OSD) algorithms. The bit error rate (BER) performance of the proposed detection algorithm is evaluated by a simulation. In the case of a 16QAM MIMO-SM system with 4 transmit and 4 receive (4 x 4) antennas, at BER = 10(-3) the proposed algorithm results in a gain improvement of about 2.5-13.5 dB over the previous algorithms. The proposed detection algorithm was designed in a hardware description language (HDL) and synthesized to gate-level circuits using 0.18 mu m 1.8V CMOS standard cell library. The results show that the proposed algorithm can be implemented without increasing the hardware costs significantly.

关键词： multiple-input multiple-output ordered successive detection QR decomposition spatial multiplexing sorted QR decomposition symbol detection

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Analysis of 2 x 2 MIMO array loaded by artificial magnetic conductor with improved gain, isolation, and bandwidth using equivalent transmission line model for indoor wireless base station

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2022年第10期32卷 e23307-e23307页

作者： Malekpoor, Hossein Arak Univ Fac Engn Dept Elect Engn Arak *** Iran

A low profile printed dipole antenna (PDA) backed by broadband Giuseppe Peano fractal artificial magnetic conductor (AMC) is introduced for wireless communications. First, a suggested PDA with a pair of microstrip dipoles excited by an E-shaped microstrip feedline is used to expand the bandwidth in the range of 5.96-7.04 GHz (S-11 <= -10 dB). Then, the suggested Giuseppe Peano fractal AMC surface as a reflector of the antenna is inserted into the PDA to gain improved radiation efficiency. The PDA with the 6 x 6 Giuseppe Peano AMC array exhibits -10 dB measured impedance bandwidth of 4.95-7.05 GHz (35%) for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 38%, enhanced gain up to 8.2 dBi, and excellent impedance matching (at least -20 dB) with directional radiation patterns. The novel AMC unit cell is realized based on the Giuseppe Peano fractal patch to operate at 6.10 GHz with an AMC bandwidth of 5.15-7.10 GHz (32%). Besides, by loading 12 x 12 AMC reflector into the four-element array of PDA, low profile wideband structure with enhanced radiation properties are achieved. The measured results show the broad bandwidths of 5-7 GHz for all elements with enhanced gains and good isolations between the elements (more than 24 dB) for multiple-input multiple-output (MIMO) systems.

关键词： artificial magnetic conductor electromagnetic band gap multiple-input multiple-output wideband AMC printed antenna

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Simulation and experimental research on the Alamouti code for ultraviolet communication

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OPTICAL ENGINEERING 2016年第1期55卷 015101-015101页

作者： Guo, Li Liu, Kunlun Meng, Dedan Mu, Xidong Han, Dahai Beijing Univ Posts & Telecommun Key Lab Univ Wireless Commun Minist Educ 10 Xitucheng Rd Beijing 100876 Peoples R China Inst Informat Photon & Opt Commun 10 Xitucheng Rd Beijing 100876 Peoples R China

The Alamouti code can obtain the diversity gain utilizing the transmitting signal orthogonally without the use of a complicated decoding scheme. The modified Alamouti code for the ultraviolet (UV) communication system is studied in theoretical analysis, MATLAB (R) simulation, and offline experiment. The theoretical analysis and simulation results indicate that the usage of the Alamouti code in the UV communication system can achieve a higher diversity gain and reduce the system bit error rate more effectively than the single-input single-output and single-input multiple-output technologies. The experiments were performed to verify the simulation results. Next, we analyzed the discrepancy between the simulation results and the experimental results. These studies are helpful for UV multiple-input multiple-output communication system design and implementation. (C) The Authors. Published by SPIE

关键词： multiple-input multiple-output Space Time Code Alamouti ultraviolet communication

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