scholarly journals A Comprehensive Worst Case Bounds Analysis of IEEE 802.15.7

2021 ◽  
Vol 10 (2) ◽  
pp. 23
Author(s):  
Harrison Kurunathan ◽  
Ricardo Severino ◽  
Eduardo Tovar
Keyword(s):  
Visible Light Communication ◽  
Effective Bandwidth ◽  
Bandwidth Utilization ◽  
Medium Access ◽  
Additional Mechanism ◽  
Worst Case ◽  
Physical Layers ◽  
High Data ◽  
Time Critical ◽  
The Internet Of Things

Visible Light Communication (VLC) has been emerging as a promising technology to address the increasingly high data-rate and time-critical demands that the Internet of Things (IoT) and 5G paradigms impose on the underlying Wireless Sensor Actuator Networking (WSAN) technologies. In this line, the IEEE 802.15.7 standard proposes several physical layers and Medium Access Control (MAC) sub-layer mechanisms that support a variety of VLC applications. Particularly, at the MAC sub-layer, it can support contention-free communications using Guaranteed Timeslots (GTS), introducing support for time-critical applications. However, to effectively guarantee accurate usage of such functionalities, it is vital to derive the worst-case bounds of the network. In this paper, we use network calculus to carry out the worst-case bounds analysis for GTS utilization of IEEE 802.15.7 and complement our model with an in-depth performance analysis. We also propose the inclusion of an additional mechanism to improve the overall scalability and effective bandwidth utilization of the network.

scholarly journals Efficient OFDM transceiver design for VLC sys-tems in fading channel

2018 ◽  
Vol 7 (1.8) ◽  
pp. 245
Author(s):  
Jayakumari J ◽  
Rakhi K J
Keyword(s):  
Fading Channels ◽  
Bit Error Rate ◽  
Fading Channel ◽  
Visible Light Communication ◽  
Communication Security ◽  
Rf Systems ◽  
High Data ◽  
Data Rates ◽  
Simulation Results ◽  
Rich Spectrum

With the widespread effective usage of LEDs the visible light communication (VLC) system has brought out an increasing interest in the field of wireless communication recently. VLC is envisioned to be an appealing substitute to RF systems because of the advantages of LEDs such as high communication security, rich spectrum, etc. For achieving bearable inter symbol interference (ISI) and high data rates, OFDM can be employed in VLC. In this paper, the performance of VLC system with popular unipolar versions of OFDM viz. Flip-OFDM and ACO-OFDM is analyzed in fading channels. From the simulation results it is seen that the Flip-OFDM-VLC system outperforms the ACO-OFDM-VLC system in terms of bit error rate and is well suited for future 5G applications.

A Power Optimization Algorithm for Ad Hoc Networks with Variable Rate Control

2013 ◽  
Vol 470 ◽  
pp. 611-616
Author(s):  
Xuan Jie Ning ◽  
Hai Zhao ◽  
Mao Fan Yang ◽  
Dan Wu
Keyword(s):  
Ad Hoc Networks ◽  
Rate Control ◽  
Ad Hoc ◽  
Transmission Rate ◽  
Mac Protocol ◽  
Network Capacity ◽  
Data Rate ◽  
Medium Access ◽  
High Data ◽  
Hoc Networks

This paper is concerned with the capacity of ad hoc networks employing pure ALOHA medium access control (MAC) protocol under the effect of different transmission power levels and variable data rate control. The data rate of a certain link is related to the signal to interference plus noise ratio (SINR), and SINR is, in turn, related to the transmitted power and link distance. The increasing power conducts a high data rate, resulting in the high interference of networks. Consequently, the optimum power that yields maximum network throughput is a tradeoff between transmission rate and network interference. Mathematical model analysis for the ad hoc network capacity are presented in the paper. A revised expression to the approximate calculating of the capture probability in networks is proposed.

scholarly journals Spectrally efficient multicarrier modulation system for visible light communication

2019 ◽  
Vol 9 (2) ◽  
pp. 1184
Author(s):  
T. Deepa ◽  
Harshita Mathur ◽  
K. A. Sunitha
Keyword(s):  
Visible Light ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Reliability ◽  
Visible Light Communication ◽  
Coded Modulation ◽  
High Data ◽  
Delta Sigma ◽  
Trellis Coded ◽  
High Spectral Efficiency ◽  
Trellis Diagram

<span lang="EN-US">Visible Light Communication (VLC) has become an accolade to its radio frequency counterpart. In VLC system, orthogonal frequency division multiplexing (OFDM) has drawn much attention, because of simple equalization, high spectral efficiency, high data rate and robustness to intersymbol interference (ISI). Besides, there are emerging applications that ought to be gotten with low latency and high reliability. To diminish power requirements with no transmission capacity extension, Trellis coded modulation (TCM) is utilized as a part of the framework in which the free distance of trellis diagram is equivalent to the minimum distance between the points of constellation focuses in partitioned subsets, which augments the coding gain up i.e. the performance parameter viably. TCM together with VLC-OFDM enhances the transmission execution in reasonable frameworks. In this paper, we propose OFDM which is based on TCM and is planned and exeuted for digitized OFDM frameworks by presenting delta sigma modulation (DSM) considering VLC channel. Simulation results show that the proposed TCM based VLC-OFDM offers incredible robustness against noises and nonlinear degradation.</span>

A Review of Multi-Channel Medium Access Control Protocols for Wireless Sensor Networks

2021 ◽  
Vol 6 (6) ◽  
pp. 39-53
Author(s):  
Hanan Alahmadi ◽  
Fatma Boabdullah
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Mac Protocols ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Medium Access Control Protocols ◽  
Medium Access ◽  
Momentum Spread ◽  
High Data ◽  
Multichannel Mac

Wireless Sensor Networks (WSNs) are witnessing a momentum spread especially with the growth of the Internet of Things (IoT) paradigm. Indeed, WSNs are considered as the main enabling infrastructure for IoT networks. Nowadays, the emerging WSNs applications require not only long network lifespan but also considerably high data rate. Consequently, conceiving Multichannel MAC protocols that save the scarceenergy budget of sensor nodes while providing high network throughput is crucial for the emerging WSNs applications. In this paper, a thorough review of recent multichannel MAC protocols is provided along with a classification framework to deeply understand the design aspects for each protocol.

Light fidelity optical network a comparative performance evaluation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Devendra Kr. Tripathi ◽  
Pallavi Singh
Keyword(s):  
Communication Systems ◽  
Optical Network ◽  
Visible Light Communication ◽  
Data Rate ◽  
Comparative Performance ◽  
Modulation Formats ◽  
High Data ◽  
Modulation Format ◽  
Output Performance ◽  
High Spectral Efficiency

Abstract Light-Fidelity (Li-Fi) is the bidirectional communication technique, tenders almost unlimited bandwidth, exploit unlicensed spectrum of light waves. Accordingly, this manuscript illustrates usage of visible light communication (VLC) applied as Li-Fi, an efficient scheme to broadcast data wirelessly as well safer technique in contrary to the customary Wireless-Fidelity (Wi-Fi) networks. In support numerical simulations have been executed over the proposed Li-Fi model for the parametric variation with the data rate, laser power, modulation format and wavelength, communication length. Investigations have showed good output performance, with hike in data rate BER variation as 10−94–10−23 and testing length. Simulations of network with DPSK and NRZ modulation formats at high data transmission of 10 Gbps have showed good output performance with 10−40 with DPSK format. Li-Fi systems are quality solution for the impending communication systems save cost, provide high spectral efficiency.

Optimizing User Quality of Experience through Overlay Routing, Bandwidth Management and Dynamic Trans-Coding

2012 ◽  
pp. 160-180
Author(s):  
Maarten Wijnants ◽  
Wim Lamotte ◽  
Bart De Vleeschauwer ◽  
Filip De Turck ◽  
Bart Dhoedt ◽  
...  
Keyword(s):  
Packet Loss ◽  
Quality Of Experience ◽  
Multimedia Data ◽  
Effective Bandwidth ◽  
Bandwidth Management ◽  
Multimedia Services ◽  
Overlay Routing ◽  
Last Mile ◽  
Time Critical

Accessing multimedia services via fixed and wireless networks has become common practice. These services are typically much more sensitive to packet loss, delay and/or congestion than traditional services. In particular, multimedia data is often time critical and, as a result, network issues are not well tolerated and significantly deteriorate the user’s Quality of Experience (QoE). Therefore, the authors propose a QoE optimization platform that is able to mitigate problems that might occur at any location in the delivery path from service provider to customer. More specifically, the distributed architecture supports overlay routing to circumvent erratic parts of the network core. In addition, it comprises proxy components that realize last mile optimization through automatic bandwidth management and the application of processing on multimedia flows. This paper introduces a trans-coding service for this proxy component which enables the transformation of H.264/AVC video flows to an arbitrary bitrate. Through representative experimental results, the authors illustrate how this addition enhances the QoE optimization capabilities of the proposed platform by allowing the proxy component to compute more flexible and effective bandwidth distributions.

Improving WLAN Performance by Modifying an IEEE 802.11 Protocol

2013 ◽  
pp. 15-32
Author(s):  
Nurul I. Sarkar
Keyword(s):  
Ieee 802.11 ◽  
Ad Hoc ◽  
Packet Delay ◽  
Distributed Coordination ◽  
Bandwidth Utilization ◽  
Medium Access ◽  
802.11 Dcf ◽  
802.11 Networks ◽  
Distributed Coordination Function ◽  
Coordination Function

One of the limitations of the IEEE 802.11 distributed coordination function (DCF) protocol is its low bandwidth utilization under medium-to-high traffic loads resulting in low throughput and high packet delay. To overcome performance problems, traditional IEEE 802.11 DCF (“DCF”) protocol is modified to the buffer unit multiple access (BUMA) protocol. The BUMA protocol achieves a better system performance by introducing a temporary buffer unit at the medium access control (MAC) layer to accumulate multiple packets and combine them into a single packet (with a header and a trailer) before transmission. This paper provides an in-depth performance evaluation (by simulation) of BUMA for multiuser ad hoc and infrastructure networks. Results obtained show that the BUMA is more efficient than that of DCF. The BUMA protocol is simple and its algorithm (software) can be upgraded to 802.11 networks requiring no hardware changes. The BUMA protocol is described and simulation results are presented to verify the performance.

scholarly journals Collision-Free Advertisement Scheduling for IEEE 802.15.4-TSCH Networks

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1789 ◽  
Author(s):  
Apostolos Karalis ◽  
Dimitrios Zorbas ◽  
Christos Douligeris
Keyword(s):  
Power Consumption ◽  
Ieee 802.15.4 ◽  
Mac Protocol ◽  
High Reliability ◽  
Mobile Nodes ◽  
Medium Access ◽  
Worst Case ◽  
Channel Hopping ◽  
Transmission Schedule ◽  
Scheduling Method

IEEE802.15.4-time slotted channel hopping (TSCH) is a medium access control (MAC) protocol designed to support wireless device networking, offering high reliability and low power consumption, two features that are desirable in the industrial internet of things (IIoT). The formation of an IEEE802.15.4-TSCH network relies on the periodic transmissions of network advertising frames called enhanced beacons (EB). The scheduling of EB transmissions plays a crucial role both in the joining time and in the power consumption of the nodes. The existence of collisions between EB is an important factor that negatively affects the performance. In the worst case, all the neighboring EB transmissions of a node may collide, a phenomenon which we call a full collision. Most of the EB scheduling methods that have been proposed in the literature are fully or partially based on randomness in order to create the EB transmission schedule. In this paper, we initially show that the randomness can lead to a considerable probability of collisions, and, especially, of full collisions. Subsequently, we propose a novel autonomous EB scheduling method that eliminates collisions using a simple technique that does not increase the power consumption. To the best of our knowledge, our proposed method is the first non-centralized EB scheduling method that fully eliminates collisions, and this is guaranteed even if there are mobile nodes. To evaluate our method, we compare our proposal with recent and state-of-the-art non-centralized network-advertisement scheduling methods. Our evaluation does not consider only fixed topology networks, but also networks with mobile nodes, a scenario which has not been examined before. The results of our simulations demonstrate the superiority of our method in terms of joining time and energy consumption.

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