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Highly efficient 4-port self-decoupled multiple-input multiple-output antenna pairs operating in n46 band for 5G smartphone applications

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2022年第12期32卷 e23486-e23486页

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

A highly efficient self-isolated multiple-input multiple-output (MIMO) antenna system functioning in the n46 5G NR band (5.15-5.925 GHz) for smartphone implementation is discussed in this paper. The system is made up of two blocks of vertically printed antenna pairs, placed at the exact center of the side frames of the smartphone. Each block comprises of a self-isolated antenna pair with two inverted L-shaped radiators facing each other, a T-shaped isolating element, and a U-shaped structure placed at the back of the radiators, and is attached to the ground plane. A simple coaxial feeding structure is deployed to excite the L-shaped radiators. The T-shaped structure placed between the two radiators has a crucial role in minimizing the mutual coupling between the two radiators, and its arm serves as a radiator. The self-isolated antenna pair functions from 5.10 to 5.98 GHz, covering the entire n46 band (5.15-5.925 GHz) with over -16.8 dB isolation in the complete operating bandwidth. The parametric investigation of some ideal parameters and the antenna pair evolution stages to obtain the final structure is examined for a superior understanding of the functioning of the proposed MIMO smartphone system. The proposed self-decoupled antenna pair MIMO system operates with a very high radiation efficiency and gain in the complete operating bandwidth, with radiating efficiency, total efficiency, and peak gain greater than 92%, 85%, and 6 dB respectively. The lowest obtained envelope correlation coefficient (ECC) value is 0.025 between the two elements in the antenna pair, which is very low when compared with the ideal value of 0.5. Various other parameters like channel capacity loss (CCL), mean effective gain (MEG), total active reflection coefficient (TARC), and diversity gain (DG) of the proposed system are also calculated and examined with the experimental results to study the diversity performance of the proposed MIMO smartphone system. A prototype of the proposed 4-por

关键词： 5G n46 envelope correlation coefficient (ECC) highly efficient multiple-input multiple-output self-isolated smartphone system

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Eight-element fifth-generation multiple-input multiple-output antenna designed by modal currents cancelation

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2022年第9期32卷 e23254-e23254页

作者： Zeng, Wen-Feng Chu, Qing-Xin South China Univ Technol Sch Elect & Informat Engn Guangzhou Peoples R China

An antenna decoupling method based on modal control is proposed in this paper. Different from the previous characteristic mode decoupling methods, which excite one of the characteristic modes from each port, a pair of decoupling modes is excited simultaneously at each port. To validate our method, a head-to-head antenna pair is analyzed and designed. According to the characteristic mode analysis, an inductor-loaded coupled sheet is introduced for the head-to-head antenna pair. Thus, the resonant frequencies of decoupling modes can be tuned individually. To further demonstrate the flexibility of our design, an eight-element multiple-input multiple-output (MIMO) antenna composed of two integrated four-element blocks is designed, fabricated, and measured. The proposed antennas show good impedance matching, isolation, and diversity performance varying from 3.35 to 3.71 GHz. Both simulated and measured results show the 8 x 8 MIMO system can achieve isolations of better than 11.5 dB and envelope correlation coefficients of less than 0.2 of each port.

关键词： antenna decoupling characteristic mode multiple-input multiple-output

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Performance enhancement for a non-orthogonal multiple access system using 4 x 4 multiple-input multiple-output visible-light communication

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OPTICAL ENGINEERING 2020年第12期59卷 126104-126104页

作者： Elewah, Ibrahim A. Jasman, Faezah Ng, Shashiong Univ Sains Malaysia Inst Nano Optoelect Res & Technol George Town Malaysia Amer Coll Middle East Dept Engn & Technol Kuwait Kuwait

A multi-user visible-light communication (VLC) system based on 4 x 4 multiple-input multiple-output (MIMO) was investigated. The system consists of four light-emitting diodes (as a transmitter) and four photodetectors (as a receiver). The proposed system was simulated for two, three, and four users. The objective of this study is to optimize the system power consumption and to utilize the sum rate on the system coverage area. By expanding the system from a 2 x 2 MIMO-VLC to a 4 x 4 MIMO-VLC, the results demonstrate that the total sum rate of the system can be improved. The findings reveal that the 4 x 4 MIMO-VLC achieves a maximum sum-rate enhancement of 143% compared with the 2 x 2 MIMO-VLC. The results also show that the efficiency of 4 x 4 MIMO-VLC system with non-orthogonal multiple access (NOMA) and gain ratio power allocation (GRPA) was increased by around 181% compared to 2 x 2 MIMO-NOMA-based VLC with GRPA in combination. For the 4 x 4 MIMO-NOMA-VLC device with GRPA, the sum bit rate for two, three, and four users was increased by 40%, 33%, and 24%, respectively. Through this study, it can be concluded that GRPA scheme plays an important role in utilizing MIMO-VLC system sum rate of the MIMO-VLC system. (c) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

关键词： visible-light communication multiple-input multiple-output non-orthogonal multiple access gain ratio power allocation

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A Janus compatible software-defined underwater acoustic multiple-input multiple-output modem

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INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 2021年第4期17卷 p1-13页

作者： Singh, Surinder Crispo, Mark Bousquet, Jean-Francois Aljendi, Shadi Dalhousie Univ Dept Elect & Comp Engn UW STREAM Halifax NS B4N 4R2 Canada

This article describes the implementation of a multiple-input multiple-output acoustic communication link in shallow water conditions to enable a software-defined acoustic modem with a maximum transmission rate of 20 kbps in a 5-kHz bandwidth. The reliability improvement of a low-complexity Alamouti space-time block code is evaluated to improve the diversity in a high-rate transmission mode using single carrier modulation, as well as in a low-rate transmission mode relying on continuous-phase frequency-shift keying. Using measurements in realistic subsea conditions, the effect of the spatial channel correlation is demonstrated. It is found that for the space-time block code/continuous-phase frequency-shift keying, the spatial diversity is significantly degraded due to the high spatial correlation. In contrast, for the high-mode transmission rate, space-time block code with single carrier modulation offers a bit error rate improvement by a factor over hundred, in comparison to a single transmit element, demonstrating that the multiple-input multiple-output optimal code depends on the software-defined acoustic modem transmission mode.

关键词： Software-defined modem underwater communications multiple-input multiple-output channel characterization field-programmable gate arrays

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Reduced complexity lattice-based multiple-input multiple-output schemes

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IET COMMUNICATIONS 2019年第10期13卷 1472-1481页

作者： Ouni, Nizar Tourki, Kamel Mohaisen, Manar Bouallegue, Ridha Univ Carthage Higher Sch Commun InnovCom Lab Tunis Tunisia Univ Tunis El Manar Natl Engn Sch Tunis Tunis Tunisia Huawei Technol Co France Res Ctr Math & Algorithm Sci Lab Paris France Korea Univ Technol & Educ Dept Elect Elect & Commun Engn Cheonan South Korea

multiple-input multiple-output is being considered as a highly interesting topic for the new generation of wireless communication systems. The major challenge is how to enhance the link reliability while neither affecting the spectral efficiency nor the quality of service. To reduce the complexity of the maximum likelihood (ML) receiver, efforts have been focused on zero forcing (ZF) decoder using lattice reduction-aided (LRA) techniques. In this study, the authors propose a method that improves performance using the LRA-based precoding technique without increasing the decoder complexity. Their approach is to exploit the channel matrix to generate matrices for both the precoding and LRA detection technique. This makes it possible to achieve maximum orthogonality for the generated channel matrices while reducing considerably the noise effect. They focus on the use of the LRA-ZF for the ease of its implementation and low complexity. The proposed method outperforms LRA-minimum mean square error-based receiver and gets closer to ML receiver performance. The performance and complexity of the proposed scheme are discussed.

关键词： precoding matrix algebra MIMO communication least mean squares methods reduced complexity lattice-based multiple-input multiple-output schemes multiple-input multiple-output highly interesting topic wireless communication systems link reliability spectral efficiency quality of service maximum likelihood receiver lattice reduction-aided techniques LRA-based decoder complexity precoding generated channel matrices LRA-ZF low complexity LRA-minimum mean square error-based receiver ML receiver performance

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High-gain and volume-efficient concave-convex lens for multiple-input multiple-output visible light communication system

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OPTICAL ENGINEERING 2020年第3期59卷 035106-035106页

作者： Kumar, Ajit Ghorai, Swapan K. Birla Inst Technol Ranchi Jharkhand India

We have proposed a concave-convex lens for the multiple-input multiple-output (MIMO) visible light communication (VLC) system, which provides more received power than conventional lenses. Ray trajectories using a hemispherical lens, compound parabolic concentrator (CPC), dielectric totally internally reflecting concentrator, and the proposed lens have been simulated in COMSOL software, and it has been shown that the proposed lens provides better convergence at the exit aperture. Also, the images of individual light-emitting diodes (LEDs) are distinguishable, and hence it can support a higher diversity order for the MIMO system. It has been found that our designed lens provides 1.081 times more received power than the hemispherical lens. We have investigated that the average received power using a concave-convex lens is 2.3593 and 1.3737 times more than the received power through bare (uniform refractive index) CPC and gradient-index-based CPC lenses, respectively. We have compared the channel gain using concave-convex and hemispherical lenses considering different values of incidence and half power semiangle of LED. The concave-convex lens has more gain and better volume efficiency;therefore, it can be considered as an appropriate choice for a compact receiver system in an MIMO-VLC system. (C) 2020 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： visible light communication multiple-input multiple-output lens ray trajectories

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Performance enhancement using multiple input multiple output in dual-hop convergent underwater wireless optical communication-free-space optical communication system under strong turbulence with pointing errors

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OPTICAL ENGINEERING 2021年第10期60卷 106106-106106页

作者： Levidala, Bhargava K. Ramavath, Prasad N. Krishnan, Prabu Natl Inst Technol Karnataka Dept Elect & Commun Engn Mangalore Karnataka India

For the first time, we propose a dual-hop multiple input multiple output (MIMO)-based convergent underwater wireless optical communication (UWOC)-free-space optical (FSO) system. The UWOC and FSO links are Gamma-Gamma (GG) distributed. Closed-form expression for the average bit error rate (ABER) is derived for the proposed MIMO-based dual-hop UWOC-FSO convergent system using the GG cumulative distribution function. The end-to-end system performance analysis is carried out by considering the turbulence, attenuation, and pointing error effects for UWOC and FSO links. For the UWOC link, different oceanic conditions, such as the clear ocean, coastal ocean, and turbid harbor, are considered. Various atmospheric effects, such as clear air, fog, rain, drizzle, and haze, are considered for the FSO link. The analytical results of the proposed MIMO-based convergent system are compared with single-input single-output (SISO) system. As a result, it is observed that the proposed MIMO 2x3 scheme offers an improvement of 35 dB in the average signal-to-noise ratio compared with the SISO system at ABER of 10(-5) in the case of weak pointing error. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： free-space optical underwater wireless optical communication multiple-input multiple-output average bit error rate

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A compact printed ultra-wideband multiple-input multiple-output prototype with band-notch ability for WiMAX, LTEband43, and WLAN systems

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2019年第6期29卷 e21673-e21673页

作者： Biswal, Sonika Priyadarsini Das, Sushrut Indian Sch Mines Dept Elect Engn Indian Inst Technol Dhanbad 826004 Jharkhand India

A compact ultra-wideband multiple-input multiple-output (UWB-MIMO) antenna with good isolation and multiple band-notch abilities is developed in this work. It consists of two quadrant shaped monopole antennas backed by ground stubs. A good isolation is achieved due to the two proposed extended curved ground stubs. The frequency rejection for the WLAN system is realized by loading a capacitive loaded loop resonator adjacent to the feed line. The band rejection for the WiMAX and LTE band43 system is achieved by embedding a quadrant shaped CSRR on each radiator's surface. The measured bandwidth of the antenna is 3.06GHz-11GHz (|S-11|<-10 dB and |S-21|<-18dB) with a band rejection from 3.5 GHz-4 GHz to 5.1 GHz-5.85GHz, respectively. Time domain performances are investigated in terms of group and phase delay characteristics. Diversity characteristics are evaluated in terms of the envelope correlation coefficient, mean effective gain, and channel capacity loss.

关键词： band-notch LTE multiple-input multiple-output ultra-wideband WIMAX WLAN

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Dual-band multiple-input multiple-output antenna based on half split cylindrical dielectric resonator

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JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS 2018年第9期32卷 1152-1163页

作者： Sharma, Abhishek Sarkar, Anirban Biswas, Animesh Akhtar, M. Jaleel Indian Inst Technol Kanpur Dept Elect Engn Kanpur Uttar Pradesh India

In this article, a dual-band half split cylindrical dielectric resonator antenna is proposed for multiple-input multiple-output (MIMO) applications. The dual-band operation is achieved by simultaneously exciting TE01 delta and TE02 delta modes in an aperture coupled fed half split cylindrical dielectric resonator. The topology of four element MIMO antenna is such that it provides both spatial and polarization diversities. Over both the operating bands, the measured port-toport isolation is better than 20 dB. The proposed antenna exhibits broadside radiation with cross polarization level below -15 dB in both xz-and yz-plane. The peak gain of antenna is 4.88 and 5.32 dBi at lower and upper operating frequency, respectively. The MIMO performance of the proposed antenna is found to be good with ECC<0.06. Moreover, the channel capacity of the proposed MIMO is near to uncorrelated case for uniform propagation scenario. The proposed antenna could be suitable for LTE 22/LTE 42 and WLAN applications.

关键词： Dielectric resonator antenna LTE polarization diversity multiple-input multiple-output spatial diversity WLAN

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Performance of multiple-input multiple-output free space optics using hybrid subcarrier intensity modulation with avalanche photodiode receiver

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INTERNATIONAL JOURNAL OF COMMUNICATION NETWORKS AND DISTRIBUTED SYSTEMS 2019年第4期22卷 468-485页

作者： Giri, Rajat Kumar Patnaik, Bijayananda Int Inst Informat Technol ETC Engn Bhubaneswar 751003 Orissa India Int Inst Informat Technol Dept ETC Engn Bhubaneswar 751003 Orissa India

In order to improve the performance of a free space optical (FSO) communication system, hybrid pulse position modulation-binary phase shift keying-subcarrier intensity modulation (PPM-BPSK-SIM) technique is proposed. The system performance is further improved by using multiple-input multiple-output (MIMO) configuration and avalanche photodiode (APD) receiver. The use of multiple lasers and photo detectors in MIMO FSO system reduces the scintillation effect in the atmosphere. In this study, the impact of different parameters like irradiance, link distance, and turbulence level have been considered for the bit error rate (BER) analysis. The relevant mathematical model is also presented. The simulation results show that the hybrid PPM-BPSK-SIM scheme performs better compared to PPM and BPSK-SIM schemes. Also, APD receiver shows a noticeable BER improvement than p-type intrinsic n-type (PIN) receiver in our proposed scheme.

关键词： Free space optics FSO subcarrier intensity modulation SIM scintillation pulse position modulation PPM multiple-input multiple-output MIMO equal gain combining EGC avalanche photodiode APD

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