scholarly journals Reconfigurable Antennas: Switching Techniques—A Survey

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 336 ◽  
Author(s):  
Naser Ojaroudi Parchin ◽  
Haleh Jahanbakhsh Basherlou ◽  
Yasir I. A. Al-Yasir ◽  
Ahmed M. Abdulkhaleq ◽  
Raed A. Abd-Alhameed
Keyword(s):  
Cognitive Radio ◽  
Wireless Communication ◽  
Communication Systems ◽  
Multiple Input Multiple Output ◽  
Reconfigurable Antennas ◽  
Radio Communications ◽  
High Data ◽  
Dynamic Tuning ◽  
Implementation Techniques ◽  
Input Multiple Output

Due to the fast development of wireless communication technology, reconfigurable antennas with multimode and cognitive radio operation in modern wireless applications with a high-data rate have drawn very close attention from researchers. Reconfigurable antennas can provide various functions in operating frequency, beam pattern, polarization, etc. The dynamic tuning can be achieved by manipulating a certain switching mechanism through controlling electronic, mechanical, physical or optical switches. Among them, electronic switches are the most popular in constituting reconfigurable antennas due to their efficiency, reliability and ease of integrating with microwave circuitry. In this paper, we review different implementation techniques for reconfigurable antennas. Different types of effective implementation techniques have been investigated to be used in various wireless communication systems such as satellite, multiple-input multiple-output (MIMO), mobile terminals and cognitive radio communications. Characteristics and fundamental properties of the reconfigurable antennas are investigated.

Improving Performance of Bell Labs Layered Space-Time Systems by Multiframe Space-Time Interleavers

2020 ◽  
Vol 11 (1) ◽  
pp. 76-95
Author(s):  
Majdi Msallam ◽  
Mohiedin Wainakh
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Multiple Input Multiple Output ◽  
Low Complexity ◽  
Space Time ◽  
Time Interleaving ◽  
High Data ◽  
Input Multiple Output ◽  
A New Technique ◽  
Static Channel

Turbo-BLAST (T-BLAST) is a multiple-input multiple-output (MIMO) wireless communication system. It is based on three main concepts: Bell laboratories layered space-time (BLAST) architecture, random space-time interleaving, and the turbo principle. T-BLAST system has many advantages including high data rate, excellent performance, and low complexity. These advantages make T-BLAST one the most important choices for future wireless communication systems. In this article, the authors study the effect of the space-time interleaver on the performance of T-BLAST system. This interleaver is split into two separated stages, time interleaving followed by space interleaving. They show that, in a quasi-static channel, the enhancement in performance provided by the time interleavers is very small compared to the gain provided by space interleavers. They also propose a new technique to improve the system performance, called multiframe space-time interleaving (MUSTI). Simulation results show an improvement in performance up to 6 dB at BER=10-4 for a (2,2) configuration.

scholarly journals Networked multiple-input-multiple-output for optical wireless communication systems

2020 ◽  
Vol 378 (2169) ◽  
pp. 20190189 ◽  
Author(s):  
Zhaocheng Wang ◽  
Jiaxuan Chen
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Multiple Input Multiple Output ◽  
Optical Devices ◽  
Heterogeneous Data ◽  
Spatial Multiplexing ◽  
Optical Wireless Communication ◽  
Optical Wireless ◽  
Multiple Input ◽  
Input Multiple Output

With the escalation of heterogeneous data traffic, the research on optical wireless communication (OWC) has attracted much attention, owing to its advantages such as wide spectrum, low power consumption and high security. Ubiquitous optical devices, e.g. light-emitting diodes (LEDs) and cameras, are employed to support optical wireless links. Since the distribution of these optical devices is usually dense, multiple-input-multiple-output (MIMO) can be naturally adopted to attain spatial diversity gain or spatial multiplexing gain. As the scale of OWC networks enlarges, optical MIMO can also collaborate with network-level operations, like user/AP grouping, to enhance the network throughput. Since OWC is preferred for short-range communications and is sensitive to the directions/rotations of transceivers, optical MIMO links vary frequently and sharply in outdoor scenarios when considering the mobility of optical devices, raising new challenges to network design. In this work, we present an overview of optical MIMO techniques, as well as the cooperation of MIMO and user/AP grouping in OWC networks. In consideration of the challenges for outdoor OWC, key technologies are then proposed to facilitate the adoption of optical MIMO in outdoor scenarios, especially in vehicular ad hoc networks. Lastly, future applications of MIMO in OWC networks are discussed. This article is part of the theme issue ‘Optical wireless communication’.

scholarly journals Frequency reconfigurable antennas for cognitive radio applications: a review

2019 ◽  
Vol 9 (5) ◽  
pp. 3542
Author(s):  
Ros Marie C Cleetus ◽  
Dr. G. Josemin Bala
Keyword(s):  
Cognitive Radio ◽  
Wireless Communication ◽  
Communication Systems ◽  
Cognitive Radios ◽  
Reconfigurable Antennas ◽  
Wireless Communication Systems ◽  
Frequency Pattern ◽  
Communication Services ◽  
Effective Utilization ◽  
Antenna Characteristic

<span>Wireless communication systems undergo tremendous growth these days and devices able to operate in a number of frequencybandsarehighlydemanded. Reconfiguration in antenna characteristic striggered the evolution of antennas that can workin multiple frequency, pattern<span> or polarization </span>environment.The frequency reconfigurable antennas thuse mergedarewell suited in Cognitive Radios which take part in the effective utilization of unused bands of frequencies by continuously interacting with the RF environment. Thus, Cognitive Radios enhancetheutilization of frequency spectrum and establish reliable communication. The most recent research works carried out in the arena of Frequency Reconfigurable Antennas for Cognitive Radio applications are reviewed and summed up in this paper to present the attributes and categorization. Four techniques adopted to attain frequency reconfiguration are extensively compared in this paper to find the advantages and constraints of each methodology. The applications of the works reviewed here are not only limited to Cognitive radios, but extended to a number of wireless communication services like, WLAN, WiMAX, etc</span>

scholarly journals Orbital Angular Momentum-Based Multiple-Input-Multiple-Output with Receive Antenna Shift Keying for 6G

Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1567
Author(s):  
Sang-Hoon Lee ◽  
Ahmed Al Al Amin ◽  
Soo-Young Shin
Keyword(s):  
Angular Momentum ◽  
Wireless Communication ◽  
Communication Systems ◽  
Multiple Input Multiple Output ◽  
Wireless Communication Systems ◽  
Time Code ◽  
Multiple Input ◽  
Shift Keying ◽  
Input Multiple Output ◽  
Receive Antenna

Spectral efficiency is a major concern for future 6G wireless communication systems. Thus, an appropriate scheme is needed to provide channel capacity improvement for multiple transmitters and receiver-based wireless communication systems without consuming extra resource for communication (e.g., frequency/time/code) or causing interference. Therefore, to fulfill the mentioned requirements for the future 6G wireless network, orbital angular momentum-based multiple-input-multiple-output (OAM-MIMO) multiplexing technique is incorporated with the receive antenna shift keying (RASK) technique in this study (termed as the OAM-MIMO-RASK scheme). OAM-MIMO-RASK can transfer multiple symbols from multiple transmitters to different receivers simultaneously by using multiple subchannels using the OAM and RASK techniques without any interference or additional resource (frequency/time/code). The numerical results illustrated that the proposed OAM-MIMO-RASK can achieve almost double capacity than the existing OAM-MIMO scheme and significantly higher capacity than the existing RASK-based scheme for different values of signal-to-noise ratio. Moreover, the simulation result is validated by the theoretical result which is also shown by the numerical result. In addition, due to different normalized distances from the transmitters and receivers, the proposed OAM-MIMO-RASK scheme can achieve almost double capacity than the existing OAM-MIMO scheme by using OAM-MIMO and RASK technique effectively which is also depicted by the numerical results.

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