scholarly journals Performance Analysis of Hard-Switching Based Hybrid FSO/RF System over Turbulence Channels

Computation ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 28 ◽  
Author(s):  
Hira Khalid ◽  
Sajid Sheikh Muhammad ◽  
Hector E. Nistazakis ◽  
George S. Tombras
Keyword(s):  
Communication Networks ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Numerical Comparison ◽  
Wireless Communication Networks ◽  
High Data ◽  
Data Rates ◽  
Turbulence Effect ◽  
Increasing Demand ◽  
Alternative Good

The hybrid system of free space optic (FSO) and radio frequency (RF) has come forth as alternative good solution for increasing demand for high data rates in wireless communication networks. In this paper, wireless networks with hard-switching between FSO and RF link are analyzed, assuming that at a certain time point either one of the two links are active, with FSO link having higher priority. As the signal-to-noise ratio (SNR) of FSO link falls below a certain selected threshold, the RF link is activated. In this work, it is assumed that the FSO link follows Gamma-Gamma fading due to the atmospheric turbulence effect whereas RF link experiences Rayleigh fading. To analyze the proposed hybrid model, analytical expressions are derived for the outage probability, bit error rate and ergodic capacity. A numerical comparison is also done between the performances of the proposed hybrid FSO/RF model and the single FSO model.

scholarly journals A Single Detector Versus an Array of Detectors Receiver in Free-Space Optical Communications: A Performance Comparison

2021 ◽  
Author(s):  
Muhammad Salman Bashir ◽  
Ming-Cheng Tsai ◽  
Mohamed-Slim Alouini
Keyword(s):  
Communication Networks ◽  
Free Space ◽  
Performance Comparison ◽  
Wireless Communication Networks ◽  
Free Space Optical ◽  
Error Performance ◽  
Probability Of Error ◽  
High Data ◽  
Data Rates ◽  
Single Detector

Free-space optical (FSO) communications is an important technology that will be used for supporting high data-rates in the backhaul of next generation of wireless communication networks. In this paper, we have compared the probability of error performance of two types of receivers used in FSO today: a receiver based on a single detector, and a receiver based on an array of detectors. The performance of these two receivers is compared for a number of fusion algorithms for an array of detectors such as equal gain combiner (EGC), selection combiner (SC), switched combiner (SWC) and the maximal ratio combiner (MRC). From this study, we conclude that even though the array of detectors adds more noise in the sufficient statistic by virtue of large number of detectors, using more computationally expensive fusion algorithms (such as SC and MRC) can help us achieve a superior probability of error performance as opposed to a single-detector receiver for practical channel conditions. <br>

scholarly journals A Single Detector Versus an Array of Detectors Receiver in Free-Space Optical Communications: A Performance Comparison

2021 ◽  
Author(s):  
Muhammad Salman Bashir ◽  
Ming-Cheng Tsai ◽  
Mohamed-Slim Alouini
Keyword(s):  
Communication Networks ◽  
Free Space ◽  
Performance Comparison ◽  
Wireless Communication Networks ◽  
Free Space Optical ◽  
Error Performance ◽  
Probability Of Error ◽  
High Data ◽  
Data Rates ◽  
Single Detector

Free-space optical (FSO) communications is an important technology that will be used for supporting high data-rates in the backhaul of next generation of wireless communication networks. In this paper, we have compared the probability of error performance of two types of receivers used in FSO today: a receiver based on a single detector, and a receiver based on an array of detectors. The performance of these two receivers is compared for a number of fusion algorithms for an array of detectors such as equal gain combiner (EGC), selection combiner (SC), switched combiner (SWC) and the maximal ratio combiner (MRC). From this study, we conclude that even though the array of detectors adds more noise in the sufficient statistic by virtue of large number of detectors, using more computationally expensive fusion algorithms (such as SC and MRC) can help us achieve a superior probability of error performance as opposed to a single-detector receiver for practical channel conditions. <br>

scholarly journals A Single Detector Versus an Array of Detectors Receiver in Free-Space Optical Communications: A Performance Comparison

2021 ◽  
Author(s):  
Muhammad Salman Bashir ◽  
Ming-Cheng Tsai ◽  
Mohamed-Slim Alouini
Keyword(s):  
Communication Networks ◽  
Free Space ◽  
Performance Comparison ◽  
Wireless Communication Networks ◽  
Free Space Optical ◽  
Error Performance ◽  
Probability Of Error ◽  
High Data ◽  
Data Rates ◽  
Single Detector

Free-space optical (FSO) communications is an important technology that will be used for supporting high data-rates in the backhaul of next generation of wireless communication networks. In this paper, we have comparedthe probability of error performance of two types of receivers used in FSO today: a receiver based on a single detector, and a receiver based on an array of detectors. The performance of these two receivers is compared for a number of fusion algorithms for an array of detectors such as equal gain combiner (EGC), selection combiner(SC), switched combiner (SWC) and the maximal ratio combiner (MRC). From this study, we conclude that even though the array of detectors adds more noise in the sufficient statistic by virtue of large number of detectors,using more computationally expensive fusion algorithms (such as SC and MRC) can help us achieve a superior probability of error performance as opposed to a single-detector receiver for practical channel conditions.

scholarly journals Data Downloading on the Sparse Coverage-Based Wireless Networks

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Helal Chowdhury ◽  
Janne Lehtomäki ◽  
Juha-Pekka Mäkelä ◽  
Sastri Kota
Keyword(s):  
Wireless Networks ◽  
Wireless Communication ◽  
Communication Networks ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Access Point ◽  
Wireless Communication Networks ◽  
High Data ◽  
Distance Relationship ◽  
The Impact

Infostation, hotspot, and drive-thru internet are examples of sparse coverage-based wireless networks. These wireless communication networks provide low-cost, delay insensitive high data rate services intermittently with discontinuous coverage. Radio propagation parameters, velocity of the user, distance between the user, and access point are the key factors that affect the throughput and the amount of information downloaded from such sparse coverage-based wireless networks. To evaluate the performance of such wireless communication networks analytically the impact of above mentioned factors can be modeled with simplified relationship model such as received signal strength versus distance or signal to noise ratio versus throughput. In the paper, we exploit the relationship between throughput and distance and develop two throughput distance relationship models to evaluate the performance of multirate wireless networks. These two throughput distance relationship models are used in calculation of average throughput as well as downloaded file size. Numerical values are presented for the IEEE 802.11n standard. The numerical results verify that the new proposed technique can be used as an alternative to the simulations to evaluate the performance of sparse coverage-based wireless networks.

scholarly journals Reliable Integrated Satellite Terrestrial Communications using MIMO for Mitigation of Microwave Absorption by Earths Oxygen

2019 ◽  
Vol 69 (5) ◽  
pp. 458-463 ◽  
Author(s):  
Anurag Vijay Agrawal ◽  
Meenakshi Rawat
Keyword(s):  
Communication Networks ◽  
Data Transmission ◽  
Communication Systems ◽  
Smart Cities ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Data Communication ◽  
Error Vector Magnitude ◽  
High Data ◽  
Data Rates

Microwaves are used to communicate with satellite and terrestrial communication networks. But as microwaves pass through the Earth’s atmosphere, the oxygen gas absorbs microwave. In this 5G era, when the whole world is moving towards high data-rates and reliable communications, this absorption affects the data transmission in Integrated Satellite/Terrestrial Communication (ISTC) systems, which leads to degradation of the system performance. The multiple-input-multiple-output (MIMO) technology has become a boon for modern wireless communication systems to achieve the necessities of higher data-rates and communication reliability. The paper analyses the MIMO effect on block error rate (BLER), error vector magnitude (EVM) and throughput performance of the data transmission with different MIMO configurations. The paper establishes that better data-rates as well as reliable data communication is achieved with higher order MIMO configurations. MIMO 8×1 provides 5, 20 and 42.5 times improved performance to BLER; 5.26%, 25% and 81.82% in throughput; and 10.34%, 23.07% and 28% in EVM calculations as comparable to MIMO 4×1, MIMO 2×1 and SISO 1×1, respectively at 15 dB signal-to-noise ratio (SNR). The authors also give a new concept of multi-cellular layers based mobile communication network, useful for future smart cities.

scholarly journals Latency-Aware Offloading in Integrated Satellite Terrestrial Networks

2020 ◽  
Author(s):  
Wiem Abderrahim ◽  
Osama Amin ◽  
Mohamed-Slim Alouini ◽  
Basem Shihada
Keyword(s):  
Communication Networks ◽  
Rural Areas ◽  
Access Network ◽  
High Capacity ◽  
High Load ◽  
Traffic Load ◽  
Satellite Systems ◽  
High Data ◽  
Data Rates ◽  
Terrestrial Networks

Next-generation communication networks are expected to integrate newly-used technologies in a smart way to ensure continuous connectivity in rural areas and to alleviate the traffic load in dense regions. The prospective access network in 6G should hinge on satellite systems to take advantage of their wide coverage and high capacity. However, adopting satellites in 6G could be hindered because of the {additional latency introduced}, which is not tolerable by all traffic types. Therefore, we propose a traffic offloading scheme that integrates both the satellite and terrestrial networks to smartly allocate the traffic between them while satisfying different traffic requirements. Specifically, the proposed scheme offloads the Ultra-Reliable Low Latency Communication (URLLC) traffic to the terrestrial backhaul to satisfy its stringent latency requirement. However, it offloads the enhanced Mobile Broadband (eMBB) traffic to the satellite since eMBB needs high data rates but is not always sensitive to delay. Our scheme is shown to reduce the transmission delay of URLLC packets, decrease the number of dropped eMBB packets, and hence improve the network's availability. Our findings highlight that the inter-working between satellite and terrestrial networks is crucial to mitigate the expected high load on the limited terrestrial capacity.<br>

scholarly journals Time and Spatial Jitter Influence on the Performance of FSO Links with DF Relays and OC Diversity over Turbulence Channels

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 318
Author(s):  
Panagiotis J. Gripeos ◽  
Hector E. Nistazakis ◽  
Andreas D. Tsigopoulos ◽  
Vasilis Christofilakis ◽  
Evgenia Roditi
Keyword(s):  
Critical Factor ◽  
Weather Conditions ◽  
Optical Wireless Communications ◽  
Time Jitter ◽  
Diversity Techniques ◽  
High Data ◽  
Mathematical Expressions ◽  
Data Rates ◽  
Turbulence Effect ◽  
The Many

FSO communication is a viral technology among optical wireless communications, gathering the interest of both researchers and manufacturers. This is because of the many advantages associated with FSO communication, including high data rates, reliability, safety, and economy. However, there are several unavoidable drawbacks that shadow the performance of FSO systems. For example, atmospheric turbulence is a well-known problem related to the weather conditions of the channel, which causes the scintillation effect. Also, spatial jitter due to pointing errors is a critical factor of the link’s performance, caused by occasional misalignments between the transmitter and the receiver. Moreover, time jitter is another limiting agent that deteriorates the total throughput, inducing bit stream misdetections, caused by the arrival of out-of-sync pulses. All three effects have been exhaustively studied and many statistical models and interesting solutions have been proposed in the literature to estimate their magnitude and compensate for their impact. In this work, the turbulence effect was treated by Málaga distribution, the spatial jitter effect was regulated by the non-zero boresight model, and the time jitter effect was modeled by the generalized Gaussian distribution. Various modulation schemes were studied, along with DF multi-hop and optimal combining diversity techniques at the receiver’s end. New, accurate mathematical expressions of average BER performance have been obtained, and valuable conclusions were drawn thanks to the presented numerical results.

scholarly journals Optical Camera Communications for IoT–Rolling-Shutter Based MIMO Scheme with Grouped LED Array Transmitter

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3361 ◽  
Author(s):  
Shivani Rajendra Teli ◽  
Vicente Matus ◽  
Stanislav Zvanovec ◽  
Rafael Perez-Jimenez ◽  
Stanislav Vitek ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Multiple Input Multiple Output ◽  
Raspberry Pi ◽  
High Data ◽  
Data Throughput ◽  
Data Rates ◽  
Led Array ◽  
Communication Links ◽  
Input Multiple Output

In optical camera communications (OCC), the provision of both flicker-free illumination and high data rates are challenging issues, which can be addressed by utilizing the rolling-shutter (RS) property of the image sensors as the receiver (Rx). In this paper, we propose an RS-based multiple-input multiple-output OCC scheme for the Internet of things (IoT) application. A simplified design of multi-channel transmitter (Tx) using a 7.2 × 7.2 cm2 small 8 × 8 distributed light emitting diode (LED) array, based on grouping of LEDs, is proposed for flicker-free transmission. We carry out an experimental investigation of the indoor OCC system by employing a Raspberry Pi camera as the Rx, with RS capturing mode. Despite the small area of the display, flicker-free communication links within the range of 20–100 cm are established with data throughput of 960 to 120 bps sufficient for IoT. A method to extend link spans up to 1.8 m and the data throughput to 13.44 kbps using different configurations of multi-channel Tx is provided. The peak signal-to-noise ratio of ~14 and 16 dB and the rate of successfully received bits of 99.4 and 81% are measured for the shutter speeds of 200 and 800 µs for a link span of 1 m, respectively.

scholarly journals Cellular Network Infrastructure: The Future of Fog Monitoring?

2015 ◽  
Vol 96 (10) ◽  
pp. 1687-1698 ◽  
Author(s):  
Noam David ◽  
Omry Sendik ◽  
Hagit Messer ◽  
Pinhas Alpert
Keyword(s):  
Communication Networks ◽  
Low Cost ◽  
Real Data ◽  
Near Surface ◽  
Theoretical Simulation ◽  
High Data ◽  
Data Rates ◽  
Crucial Information ◽  
Current Monitoring ◽  
Commercial Microwave Links

Abstract Severe visibility limitations resulting from fog may lead to acute transportation accidents and high losses of property and lives. Thus, reliable monitoring facilities are of extreme importance. Nevertheless, current monitoring instruments suffer from low spatial resolution, high costs, or lack of precision at near-surface levels. It has, however, recently been shown that the commercial microwave links that form the infrastructure of cellular communication networks can provide crucial information regarding the appearance of dense fog and its intensity. Typical microwave systems currently in operation make use of frequencies between 6 and 40 GHz and, thus, can only monitor heavy fog. However, there is a growing demand for high data rates and expanded bandwidth in modern mobile radio networks. As a result, higher frequencies (e.g., around 80 GHz) are being implemented in order to fulfill these increased requirements. Notably, the attenuation induced as a result of fog at a given intensity increases as operating frequency rises, allowing, for the first time, the possibility of using this system to monitor typical fog intensities, at high resolution and low cost. Here, a theoretical simulation is presented in which simulated fog patches are introduced into an area where a network of links is deployed. Two-dimensional maps are generated utilizing the simulated microwave network to represent sensitivity thresholds for fog detection at three different frequencies: 20, 38, and 80 GHz. Real-data measurements of fog are also demonstrated using 38-GHz band links. The results indicate the vast future potential of commercial microwave links as an opportunistic system for monitoring fog.

scholarly journals Intelligent Reflecting Surfaces Assisted UAV Communications for IoT Networks: Performance Analysis

2021 ◽  
Author(s):  
sami muhaidat
Keyword(s):  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Symbol Error Rate ◽  
Upper And Lower Bounds ◽  
Present Contribution ◽  
Analytic Expressions ◽  
Increasing Demand ◽  
Set Up ◽  
Reflecting Surfaces

<p>The increasing demand for wireless connectivity and the emergence of the notion of the Internet of Everything require new communication paradigms that will ultimately enable a plethora of new applications and new disruptive technologies. In this context, the present contribution investigates the use of the recently introduced intelligent reflecting surface (IRS) concept in unmanned aerial vehicles (UAV) enabled communications aiming to extend the network coverage and improve the communication reliability as well as spectral efficiency of Internet of Things (IoT) networks. In particular, we first derive tractable analytic expressions for the achievable symbol error rate (SER), ergodic capacity, and outage probability of the considered set up. Following this, we also derive tight upper and lower bounds on the average signal-to-noise ratio (SNR). Our derivations are then compared with the corresponding asymptotic performance, based on the central limit theorem (CLT) assumption, which reveals that the asymptotic SNR falls within the area between derived bounds, and approaches either bound depending on the number of reflective elements (REs). We further show that the asymptotic SER becomes in a tight agreement with the corresponding exact simulation SER for > 16. In addition, the offered results demonstrate that the use of the IRS is significantly effective as they assist in improving the achievable SER by five orders of magnitude. We further demonstrate that, in terms of achievable ergodic capacity, IRS-assisted UAV communication systems can exhibit ten times higher capacity compared to conventional UAV communications. Based on the above, these results and related insights are anticipated to be useful in the design and deployment of IRS-assisted UAV systems in the context of beyond 5G communications, such as 6G communications.</p>

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