scholarly journals Performance Analysis of Intelligent Reflecting Surface-Assisted Multi-Users Communication Networks

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2084
Author(s):  
Muhamad Mustaghfirin ◽  
Keshav Singh ◽  
Sudip Biswas ◽  
Wan-Jen Huang
Keyword(s):  
Quality Of Service ◽  
Communication Networks ◽  
Channel Model ◽  
Estimation Error ◽  
Channel Estimation Error ◽  
Decode And Forward ◽  
Line Of Sight Propagation ◽  
Reflecting Surface ◽  
Aided Communication

An intelligent reflecting surface (IRS) is an array that consists of a large number of passive reflecting elements. Such a device possesses the potential to extend the coverage of transmission in future communication networks by overcoming the effects of non line-of-sight propagation. Accordingly, to present the case for utilizing IRS panels in future wireless networks, in this paper, we analyze a multi-user downlink network aided by IRS. In particular, by using a realistic 5G channel model, we compare the performance of the IRS-aided network with a decode and forward (DF) relay-aided scenario and a network without IRS or relay. Our analysis revealed the following: (i) At best, communication aided by a DF relay with perfect channel state information (CSI) could match the performance of the IRS-aided network with imperfect CSI when the channel estimation error was high and the number of users was large. (ii) IRS-aided communication outright outperformed the DF relay case when the transmit power was high or the number of users in the network was low. (iii) Increasing the number of elements in an IRS translated to greater quality of service for the users. (iv) IRS-aided communication showed better energy efficiency compared with the other two scenarios for higher quality of service requirements.

Simulation modeling of packet switching network segment functioning

2019 ◽  
pp. 75-82
Author(s):  
D. V. Shelkovoy ◽  
A. A. Chernikov
Keyword(s):  
Quality Of Service ◽  
Communication Networks ◽  
Simulation Modeling ◽  
Data Stream ◽  
Switching Network ◽  
Data Packets ◽  
Channel Resource ◽  
Switching Node ◽  
Joint Examination

The testing results of required channel resource mathematical estimating models for the for serving the proposed multimedia load in packet-switched communication networks are presented in the article. The assessment of the attainable level of quality of service at the level of data packet transportation was carried out by means of simulation modeling of the functioning of a switching node of a communication network. The developed modeling algorithm differs from the existing ones by taking into account the introduced delay for processing each data stream packet arriving at the switching node, depending on the size of the reserved buffer and the channel resource for its maintenance. A joint examination of the probability of packet loss and the introduced delay in the processing of data packets in the border router allows a comprehensive assessment of the quality of service «end to end», which in turn allows you to get more accurate values of the effective data transmitted rate by aggregating flows at the entrance to the transport network.

scholarly journals Energy Optimization of a Laser-Powered Hovering-UAV Relay in Optical Wireless Backhaul

2021 ◽  
Author(s):  
Muhammad Salman Bashir ◽  
Mohamed-Slim Alouini
Keyword(s):  
Quality Of Service ◽  
Communication Systems ◽  
Low Cost ◽  
Base Stations ◽  
Achievable Rate ◽  
Optical Wireless ◽  
Free Space Optical ◽  
Decode And Forward ◽  
Wireless Backhaul

<div>Due to their flexibility and low cost deployment, unmanned aerial vehicles (UAV) will most likely act as base stations and backhaul relays in the next generation of wireless communication systems. However, these UAVs---in the untethered mode---can only operate for a finite time due to limited energy they carry in their batteries. In free-space optical communications, one solution is to transport both the data and the energy from the source to the UAV through the laser beam---a concept known as <i>simultaneous lightwave information and power transfer</i> (SLIPT). In this study, we have analyzed the SLIPT scheme for laser-powered decode-and-forward UAV relays in an optical wireless backhaul. The major goal of this study is to optimally allocate the received beam energy between the decoding circuit, the transmitting circuit and the rotor block of the relay in order to maximize a quality-of-service metric such as maximum achievable rate, outage or error probabilities. As expected, we note that the optimal power allocation depends heavily on the source-relay and relay-destination channel conditions. In the final part of this study, we have maximized the operational time of the UAV relay given that the maximum achievable rate stays above a certain threshold in order to meet a minimum quality-of-service requirement.</div>

scholarly journals Optimal approach for building scheduling algorithm in satellite communication

2018 ◽  
Vol 7 (2.28) ◽  
pp. 181
Author(s):  
Ali M. Al-Saegh
Keyword(s):  
Quality Of Service ◽  
Communication Networks ◽  
Satellite Communication ◽  
Scheduling Algorithm ◽  
Satellite Communications ◽  
Satellite Networks ◽  
Communication Links ◽  
Optimal Approach ◽  
Proper Solutions

Building scheduling algorithms in satellite communication links became a necessity according to the typical problems that satellite networks suffers from, such as congestions, jamming, mobility, atmospheric impairment, and achieving the quality of service (QoS) requirements. However, building efficient algorithms needs several considerations that should be taken into account. Such as satellite and earth station node(s), link parameters and specifications, along with the service requirements and limitations. This paper presents efficient approach for accumulating the effective considerations that the designer should employ as a framework for building proper and efficient scheduling algorithm. The proposed approach provides proper solutions to the satellite communications impairments and satisfies the quality of service requirements in satellite communication networks.  

A Mechanism for Securing Hybrid Cloud Outsourced Data

2015 ◽  
pp. 73-83 ◽  
Author(s):  
Abdullah El-Haj ◽  
Shadi Aljawarneh
Keyword(s):  
Quality Of Service ◽  
Communication Networks ◽  
Security Policy ◽  
Detection System ◽  
Network Access ◽  
Network Resources ◽  
Outsourced Data ◽  
Secure Data Transmission ◽  
Cloud Network

The existing research related to security mechanisms only focuses on securing the flow of information in the communication networks. There is a lack of work on improving the performance of networks to meet quality of service (QoS) constrains for various services. The security mechanisms work by encryption and decryption of the information, but do not consider the optimised use of the network resources. In this paper the authors propose a Secure Data Transmission Mechanism (SDTM) with Preemption Algorithm that combines between security and quality of service. Their developed SDTM enhanced with Malicious Packets Detection System (MPDS) which is a set of technologies and solutions. It enforces security policy and bandwidth compliance on all devices seeking to access Cloud network computing resources, in order to limit damage from emerging security threats and to allow network access only to compliant and trusted endpoint devices.

scholarly journals Block-Type Pilot Arrangement with Alternating Polarity for ICI Mitigation in Mobile OFDM Systems

2013 ◽  
Vol 9 (3) ◽  
pp. 178 ◽  
Author(s):  
Titiek Suryani ◽  
Gamantyo Hendrantoro
Keyword(s):  
Channel Estimation ◽  
Doppler Shift ◽  
Channel Model ◽  
Estimation Error ◽  
Least Square ◽  
Channel Estimation Error ◽  
Piecewise Linear Approximation ◽  
Modulation Scheme ◽  
Block Type ◽  
Time Varying

Improvement on Inter Carrier Interference (ICI)mitigation techniques for OFDM caused by Doppler effectsthrough minimizing channel estimation error and decreasingchannel time varying rate is investigated. The performanceof pilot-aided channel estimation techniques depends on pilot placement and arrangement and also on the channel time varying rate. The block-type and comb-type pilot arrangements are studied through different numbers of guard bands, with or without the involvement of the Doppler shift compensation. The estimation of channel at mid-point of each OFDM symbol is derived from pilot frequencies based on the least square algorithm while the channel interpolation is done using piecewise linear approximation. For ICI mitigation technique we implement frequency domain zero forcing equalizer. We compare the performance of schemes with different pilot arrangementsand Doppler shift compensations by measuring bit error rate with QPSK as sub-channel modulation scheme and with mobileto-fixed of single ring scattering as channel model. The results are in favour of block-type pilot arrangements with alternating polarity and Doppler compensation of 0:55 times the maximum Doppler shift.

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