scholarly journals Capacity Analysis of IRS-Based UAV Communications with Imperfect Phase Compensation

2021 ◽  
Author(s):  
MOHAMMAD AHMAD Al-Jarrah ◽  
Emad Alsusa ◽  
Arafat Al-Dweik ◽  
Daniel K. C. So
Keyword(s):  
Signal To Noise Ratio ◽  
Phase Error ◽  
Random Variable ◽  
System Capacity ◽  
High Signal ◽  
Capacity Analysis ◽  
Capacity Loss ◽  
Von Mises ◽  
Reflecting Surfaces ◽  
Incident Waves

<div>This paper presents the capacity analysis of unmanned aerial vehicles (UAVs) communications supported by flying intelligent reflecting surfaces (IRSs). In the considered system, some of the UAVs are equipped with an IRS panel that applies certain phase-shifts to the incident waves before being reflected to the receiving UAV. In contrast to existing work, this letter considers the effect of imperfect phase knowledge on the system capacity, where the phase error is modeled as a von Mises random variable with parameter k. Analytical results, corroborated by Monte Carlo simulations, show that the achievable capacity is dependent on the phase error, however, the capacity loss becomes negligible at high signal-to-noise ratio (SNR) and when k>6.</div>

scholarly journals Capacity Analysis of IRS-Based UAV Communications with Imperfect Phase Compensation

2021 ◽  
Author(s):  
MOHAMMAD AHMAD Al-Jarrah ◽  
Emad Alsusa ◽  
Arafat Al-Dweik ◽  
Daniel K. C. So
Keyword(s):  
Signal To Noise Ratio ◽  
Phase Error ◽  
Random Variable ◽  
System Capacity ◽  
High Signal ◽  
Capacity Analysis ◽  
Capacity Loss ◽  
Von Mises ◽  
Reflecting Surfaces ◽  
Incident Waves

<div>This paper presents the capacity analysis of unmanned aerial vehicles (UAVs) communications supported by flying intelligent reflecting surfaces (IRSs). In the considered system, some of the UAVs are equipped with an IRS panel that applies certain phase-shifts to the incident waves before being reflected to the receiving UAV. In contrast to existing work, this letter considers the effect of imperfect phase knowledge on the system capacity, where the phase error is modeled as a von Mises random variable with parameter k. Analytical results, corroborated by Monte Carlo simulations, show that the achievable capacity is dependent on the phase error, however, the capacity loss becomes negligible at high signal-to-noise ratio (SNR) and when k>6.</div>

scholarly journals Optimum Elements Selection in IRS-Assisted UAV Communications with Phase Errors

2021 ◽  
Author(s):  
sobia Jangsher ◽  
Arafat Al-Dweik ◽  
MOHAMMAD AHMAD Al-Jarrah ◽  
Emad Alsusa ◽  
Mohamed-Slim Alouini
Keyword(s):  
Selection Process ◽  
Least Square ◽  
High Signal ◽  
Phase Errors ◽  
Optimum Selection ◽  
Np Hard Problem ◽  
Aerial Vehicle ◽  
Lower Complexity ◽  
Von Mises ◽  
Reflecting Surfaces

<div>This letter considers minimizing the bit error rate (BER) of unmanned aerial vehicle (UAV) communications assisted by intelligent reflecting surfaces (IRSs). By noting that increasing the number of IRS elements in the presence of phase errors does not necessarily improve the BER, it is crucial to use only the elements that contribute to reducing the BER. Consequently, we propose an efficient algorithm to activate only the elements that improve the BER. The proposed algorithm has lower complexity and comparable BER to the optimum selection process, which is an NP-hard problem. The accuracy of the estimated phase is evaluated by deriving the probability distribution function (PDF) of the least-square (LS) channel estimator, and showing that the PDF can be closely approximated by the von Mises distribution at high signal-to-noise ratios (SNRs). The obtained analytical and simulation results show that using all the available reflectors can significantly deteriorate the BER, and thus, elements’ selection is necessary. In particular scenarios, using about 26% of the reflectors provides more than 10 fold BER reduction.</div>

scholarly journals Secrecy Analysis and Error Probability of LIS-Aided Communication Systems under Nakagami-m Fading

Entropy ◽  
2021 ◽  
Vol 23 (10) ◽  
pp. 1284
Author(s):  
Ricardo Coelho Ferreira ◽  
Michelle S. P. Facina ◽  
Felipe A. P. de Figueiredo ◽  
Gustavo Fraidenraich ◽  
Eduardo Rodrigues de Lima
Keyword(s):  
Mobile Communications ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Error Probability ◽  
Signal To Noise Ratio ◽  
Phase Error ◽  
Secrecy Outage Probability ◽  
Single Antenna ◽  
Secrecy Outage ◽  
Von Mises

Large intelligent surfaces (LIS) are a new trend to achieve higher spectral efficiency and signal-to-noise ratio in mobile communications. For this reason, this paper proposes metrics to analyze the performance of systems with multiple antennas aided by LIS and derive the spectral efficiency, secrecy outage probability, and bit error probability in an environment with Nakagami-m distributed fading. In addition to an eavesdropper, there is a single-antenna user, an array of antennas at the transmitter side and the possibility of a direct link between transmitter and receiver. This study assumes that the LIS performs non-ideal phase cancellation leading to a residual phase error that follows a Von Mises distribution, and shows that the resulting channel can be accurately approximated by a Gamma distributed SNR whose parameters are analytically derived. From these formulas, it is possible to evaluate the effect of the strength of the line-of-sight link by varying the Nakagami parameter, m.

scholarly journals Effective Capacity Analysis of NOMA Networks with Short Packets

2021 ◽  
Vol 11 (23) ◽  
pp. 11438
Author(s):  
Xiurong Zhang ◽  
Xinwei Yue ◽  
Shaoli Kang
Keyword(s):  
Error Probability ◽  
Signal To Noise Ratio ◽  
Transmission Error ◽  
Effective Capacity ◽  
Low Latency ◽  
High Signal ◽  
Capacity Analysis ◽  
Energy Internet ◽  
Planning And Design ◽  
Asymptotic Expressions

Low latency and a massive connection have become the requirements of energy internet wireless communication. Effective capacity analysis of non-orthogonal multiple access (NOMA) networks with short packets is of vital importance in energy internet communication planning and design. Low-latency communications are one of the main application scenarios in next-generation wireless networks. This paper focuses on the effective capacity of NOMA networks, where the finite blocklength, delay exponent, and transmission error probability are taken into account. New exact and asymptotic expressions of effective capacities are derived for arbitrarily ordered users with a finite blocklength. Based on the analytical results, the high Signal-to-Noise Ratio slopes of effective capacity in NOMA networks are carefully attained. The numerical results validate that (a) non-orthogonal users are capable of obtaining a larger effective capacity when the blocklength decreases, and that (b), as the value of the error probability and delay exponent increases, the effective capacity of non-orthogonal users worsens.

scholarly journals The research of power allocation algorithm with lower computational complexity for non-orthogonal multiple access

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ying Lin ◽  
Suoping Li ◽  
Kejun Jia ◽  
Kathryn L. Kingsley
Keyword(s):  
Computational Complexity ◽  
Power Allocation ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
System Capacity ◽  
High Signal ◽  
Allocation Algorithm ◽  
Low Snr ◽  
High Spectral Efficiency ◽  
Noise Ratio

Abstract Non-orthogonal multiple access (NOMA) has very high spectral efficiency and system capacity. NOMA has become one of the most competitive access solutions in 5G systems. In this article, the principle of NOMA is discussed first. Then, the NOMA system capacity optimisation problems are studied. Signal to interference plus noise ratio (SINR) is an important factor which affects the system capacity. The SINR of current user n is only related to the power allocated to users n+1 to N with high signal-to-noise ratio (SNR) but not interfered by users with low SNR. Therefore, a tree topology power allocation (TTPA) algorithm is introduced. When users are allocated to each layer of the tree structure, the current power allocation of each layer will not be affected by the previous layer. Through theoretical analysis, TTPA can achieve the same performance as the full search power allocation algorithm; however, its computational complexity is reduced from exponential to constant. It can be seen from the numerical simulation results that the proposed algorithm can achieve higher system capacity and has lower computational complexity.

scholarly journals Improved Hybrid Precoder Design for Secure mmWave MIMO Communications

2020 ◽  
Vol 26 (4) ◽  
pp. 72-77 ◽  
Author(s):  
Yasin Kabalci ◽  
Muhammad Ali
Keyword(s):  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Phase Shifters ◽  
Propagation Loss ◽  
System Capacity ◽  
High Signal ◽  
Secrecy Rate ◽  
Low Snr ◽  
Recent Approach ◽  
Data Rates

Key challenges of emerging mobile communication systems are to provide higher data rates, diverse device connectivity, low latency, higher system capacity, and low energy consumption. The communication systems exploiting the millimeter-wave (mmWave) band are realized to resolve thereof inevitable issues. However, security is considered as one of the challenging issues in mmWave communication in addition to unavoidable problems (e.g., propagation loss, penetration loss, and fading). This study aims to construct efficient secure hybrid precoder with low-resolution phase shifters that can protect legitimate information from eavesdropping by employing coordinated analog precoder and combiner algorithms and improve the secrecy rate. Moreover, in order to further enhance the secrecy rate, hybrid precoder are obtained using an efficient channel. This work compares its results with the recent approach reported in the literature, which indicates that our proposed model outperforms at high signal-to-noise ratio (SNR) values, while our model provides similar performance at low SNR values. Simulation studies also confirm the effectiveness of the proposed hybrid precoder to achieve maximum secrecy rate.

scholarly journals Performance Analysis of Hybrid Protocol Based AF EH Relaying over Asymmetric Fading Channels

Information ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 50 ◽  
Author(s):  
Xutao Sheng ◽  
Guangyue Lu ◽  
Liqin Shi ◽  
Yinghui Ye
Keyword(s):  
Fading Channels ◽  
Rayleigh Fading ◽  
Signal To Noise Ratio ◽  
System Capacity ◽  
Rician Fading ◽  
High Signal ◽  
Amplify And Forward ◽  
Relay Nodes ◽  
Energy Constrained ◽  
Selection Of

Simultaneous wireless information and power transfer is a practicable solution to encourage energy-constrained relay nodes to cooperate with the source to transmit information to the destination. In this paper, we study the outage performance of hybrid protocol based amplify-and-forward (AF) relay networks over asymmetric fading channels, where the source-relay link and the relay-destination link are subjected to Rician fading and Rayleigh fading, respectively. In particular, we derive the lower bound of outage probability and the upper bound of outage capacity based on a high signal-to-noise ratio approximation, respectively. We further investigate the effects of various system parameters, such as the parameters of hybrid protocol, the target rate, and the Rician K-factor, on the investigated network. It is shown that a good selection of parameters of hybrid protocol is of significance to improve system capacity, and that a larger Rician factor is desirable in the investigated network.

scholarly journals IRS-Assisted UAV Communications with Imperfect Phase Compensation

2020 ◽  
Author(s):  
Arafat Al-Dweik ◽  
MOHAMMAD AHMAD Al-Jarrah ◽  
Emad Alsusa ◽  
Mohamed-Slim Alouini ◽  
Youssef Iraqi
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Channel Model ◽  
Phase Error ◽  
Propagation Path ◽  
Line Of Sight ◽  
Rician Fading ◽  
Phase Compensation ◽  
Communications Systems ◽  
Von Mises ◽  
Reflecting Surfaces

<div>This work presents a performance analysis on unmanned aerial vehicles (UAVs) assisted wireless</div><div>communications systems, where one of the UAVs supports intelligent reflecting surfaces (IRS). As the</div><div>estimation and compensation of the end-to-end phase for each propagation path is prone to errors, imperfect</div><div>phase compensation at the IRS is taken into consideration. The performance is derived in terms of symbol</div><div>error rate (SER) and outage probability, where the phase error is modeled using the von Mises distribution.</div><div>The air-to-air (A2A) channel for</div><div>each propagation path is modeled as a single dominant line-of-sight (LoS) component, and the results are</div><div>compared to the Rician channel model. The obtained results reveal that the considered A2A model can be</div><div>used to accurately represent the A2A channel with Rician fading.</div>

scholarly journals IRS-Assisted UAV Communications with Imperfect Phase Compensation

2020 ◽  
Author(s):  
Arafat Al-Dweik ◽  
MOHAMMAD AHMAD Al-Jarrah ◽  
Emad Alsusa ◽  
Mohamed-Slim Alouini ◽  
Youssef Iraqi
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Channel Model ◽  
Phase Error ◽  
Propagation Path ◽  
Line Of Sight ◽  
Rician Fading ◽  
Phase Compensation ◽  
Communications Systems ◽  
Von Mises ◽  
Reflecting Surfaces

<div>This work presents a performance analysis on unmanned aerial vehicles (UAVs) assisted wireless</div><div>communications systems, where one of the UAVs supports intelligent reflecting surfaces (IRS). As the</div><div>estimation and compensation of the end-to-end phase for each propagation path is prone to errors, imperfect</div><div>phase compensation at the IRS is taken into consideration. The performance is derived in terms of symbol</div><div>error rate (SER) and outage probability, where the phase error is modeled using the von Mises distribution.</div><div>The air-to-air (A2A) channel for</div><div>each propagation path is modeled as a single dominant line-of-sight (LoS) component, and the results are</div><div>compared to the Rician channel model. The obtained results reveal that the considered A2A model can be</div><div>used to accurately represent the A2A channel with Rician fading.</div>

scholarly journals Secrecy Analysis and Error Probability of LIS-aided Communication Systems under Nakagami-m Fading

2021 ◽  
Author(s):  
Ricardo Coelho Ferreira ◽  
Michelle S. P. Facina ◽  
Felipe A. P. de Figueiredo ◽  
Gustavo Fraidenraich ◽  
Eduardo Rodrigues de Lima
Keyword(s):  
Communication Systems ◽  
Error Probability ◽  
Signal To Noise Ratio ◽  
Phase Error ◽  
Secrecy Outage Probability ◽  
Direct Link ◽  
Single Antenna ◽  
Phase Cancellation ◽  
Secrecy Outage ◽  
Von Mises

In this work, we derive the spectral efficiency, secrecy outage probability, and bit error rate of a communication system assisted by a large intelligent surface (LIS). We consider a single-antenna user and an array of antennas at the transmitter side and the possibility of a direct link between transmitter and receiver. Additionally, there is a single-antenna eavesdropper with a direct link to the transmitter, which is modeled as a Nakagami-m distributed fading coefficient. The channels from transmitter to the LIS and from the LIS to the user may or may not have the line-of-sight (LoS) and are modeled by the Nakagami- m distribution. Moreover, we assume that the LIS elements perform non-ideal phase cancellation leading to a residual phase error that assumes a Von Mises distribution. We show that the resulting channel can be accurately approximated by a Gamma distribution whose parameters are analytically estimated using the moments of the equivalent signal-to-noise ratio. We also provide an upper bound for the error probability for M-QAM modulations. With the derived formulas, we analyze the effect of the strength of the LoS link by varying the Nakagami parameter, m.

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