Lightbeam Configuration Method and Interference Elimination Resource Scheduling for Indoor Multibeam VLC Networks

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Cong-Nam Tran ◽  
Nam-Hoang Nguyen ◽  
Trong-Minh Hoang
Keyword(s):  
Transmission Rate ◽  
Resource Scheduling ◽  
Packet Delay ◽  
Access Point ◽  
Visible Light Communications ◽  
Resource Allocation Algorithm ◽  
Downlink Transmission ◽  
High Data ◽  
Interference Elimination ◽  
Multi Access

AbstractVisible light communications (VLC) is considered as an alternative communications technology for providing indoor wireless services. VLC systems are expected to offer high data transmission rate and seamless coverage. In order to achieve these requirements, VLC systems utilizing multi-lightbeam access points (multibeam VLC-AP) for downlink transmission have been proposed recently. In this paper, we present a lightbeam configuration method and an interference elimination resource scheduling mechanism (IERS) for indoor multibeam multi-access point VLC systems. The proposed lightbeam configuration method ensures seamless connectivity between user equipment and VLC-AP. The proposed IERS mechanism consists of a beam assignment algorithm and a resource allocation algorithm for eliminating co-channel interference as well as improving system performance. Performance results obtained by computer simulation indicate that there are significant improvements in terms of downlink signal to interference plus noise ratio, user throughput and packet delay when the proposed IERS mechanism is deployed.

Mobility aware of WDM-based CMO OFDM communication system

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saad M. Hardan ◽  
Ayad A. Abdulkafi ◽  
Saadi Hamad Thalij ◽  
Sherine S. Jumaah
Keyword(s):  
Wavelength Division Multiplexing ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Light Emitting Diode ◽  
Access Point ◽  
Mobile Users ◽  
Visible Light Communications ◽  
Optical Wireless Communications ◽  
High Data ◽  
The Impact

Abstract The continued increase in several mobile applications forces to replace existing limited spectrum indoor radio frequency wireless connections with high-speed ones. Visible light communications (VLC) technology has gained prominence in the development of high data rate transmission for fifth-generation networks. In optical wireless communications, light-emitting diode (LED) transmitters are used in applications that desire mobility as LED divergence enables larger coverage. Since each VLC access point covers a small area, handovers of mobile users are inevitable. Wavelength division multiplexing (WDM) can be used in VLC systems to tackle the above issue and to meet the increasing demand for indoor connectivity with high bit rates. In this paper, a new system architecture for WDM with coded modulated optical in orthogonal frequency division multiplexing (OFDM) VLC system in conjunction with red, green, blue, and yellow (RGBY) LEDs is proposed to reduce the impact of random receiver orientation of indoor mobile users over VLC downlink channels and improves the system’s bit-error-rate (BER) performance. Simulation results show that the proposed method is not affected by the user’s mobility and hence it performs better than other approaches, in terms of BER for all scenarios and at all positions. This study reveals that using WDM-OFDM-VLC with RGBY LEDs to construct a VLC system is very promising.

scholarly journals Energy Efficient Downlink Transmission in Wireless LANs by Using Low-Power Wake-Up Radio

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Suhua Tang ◽  
Sadao Obana
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Wireless Lan ◽  
Transmission Rate ◽  
Access Point ◽  
Link Quality ◽  
Saturation State ◽  
Downlink Transmission ◽  
Power Save Mode ◽  
To Receive

In the downlink of a wireless LAN, power-save mode is a typical method to reduce power consumption. However, it usually causes large delay. Recently, remote wake-up control via a low-power wake-up radio (WuR) has been introduced to activate a node to instantly receive packets from an access point (AP). But link quality is not taken into account and protocol overhead of wake-up per node is relatively large. To solve these problems, in this paper, a broadcast-based wake-up control framework is proposed, and a low-power WuR is used to receive traffic indication map from an AP, monitor link quality, and perform carrier sense. Among the nodes which have packets buffered at the AP, only those whose SNR is above a threshold will be activated, contending via a proper contention window to receive packets from the AP. Optimal SNR threshold, deduced by theoretical analysis, helps to reduce transmission collisions and false wake-ups (caused by wake-up latency) and improve transmission rate. Extensive simulations confirm that the proposed method (i) effectively reduces power consumption of nodes compared with other methods, (ii) has less delay than power-save mode in times of light traffic, and (iii) achieves higher throughput than other methods in the saturation state.

Proactive link handover deploying coordinated transmission for indoor visible light communications (VLC) networks

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Cong-Nam Tran ◽  
Trong-Minh Hoang ◽  
Nam-Hoang Nguyen
Keyword(s):  
Visible Light ◽  
High Speed ◽  
Packet Delay ◽  
Access Point ◽  
Mobile User ◽  
Visible Light Communications ◽  
Light Spectrum ◽  
Transmission Method ◽  
Access Points ◽  
Handover Scheme

AbstractVisible Light Communications (VLC) is considered as an emerging technology for indoor wireless communications to achieve high-speed and secure data transmission. Instead of using radio frequency (RF) spectrum, VLC uses the visible light spectrum to perform lighting and communications functions simultaneously. Multiple access points VLC (multi-AP VLC) networks use ceiling access point (ceiling-AP) and desk access point (desk-AP) to provide both uniform and spot lighting in order to achieve full coverage and high spectral efficiency. Because mobile user equipment (UE) require seamless connectivity when moving, fast link handover between VLC access points (VLC-AP) has to be supported in the VLC networks. In this paper, we present a coordinated multi-channel transmission method (CMcT) used to improve quality of service (QoS) of cell-edge UEs and propose a novel proactive link handover scheme deploying the CMcT method for multi-AP VLC networks. Performance results obtained by computer simulation show that the proactive link handover scheme deploying the CMcT method can significantly improve user throughput and packet delay comparing with those of other link handover schemes.

Investigating the Analysis of Power Saving Mode in IEEE 802.11 for Wi-Fi Communication

2018 ◽  
Vol 6 (3) ◽  
pp. 13-19
Author(s):  
Isam Aameer Ibrahim ◽  
Haider TH Salim ◽  
Hasan F. Khazaal
Keyword(s):  
Ieee 802.11 ◽  
Network Performance ◽  
Power Saving ◽  
Packet Delay ◽  
Access Point ◽  
Battery Life ◽  
Global Issues ◽  
Time Ratio ◽  
Power Saving Mode ◽  
Saving Mode

One of the major global issues today is energy consumption. Consequently, power management was introduced in various communication technologies. For IEEE 802.11wireless communication, there is a Power Saving Mode scheme (PSM) for increase the battery life of cell phone. In this PSM, there are two key parameters: beacon period interval (BI) and listen interval(LI). In most work these values are chosen arbitrary. Here, a scheme to determine the optimal BI and LI for accomplishing the most astounding conceivable vitality proficiency is introduced. This is implemented with the application of a numerical sample to the standard IEEE 802.11 PSM and Access Point-PSM (AP-PSM) schemes. To ensure the quality of network performance analysis on the normal and change of parcel delays is doing. The well-known queuing (M/G/I) model with bulk services are utilized. After the implementation of the proposed analysis, “maximum rest plan time ratio optimal Sleep Scheme (OSS)” which is when participate stations stay in the doze mode it can be determined. In this research shows that the optimal BI and LI produce optimal OSS time ratio scheme also achieved optimal average and variance of packet delay.

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.

Using a Sorted QR Decomposition Algorithm for Multiuser MIMO Downlink Transmission

2021 ◽  
Vol I (I) ◽  
Author(s):  
S Lakshmi Narayanan ◽  
Robert Theivadas J
Keyword(s):  
Bit Error Rate ◽  
Spectral Efficiency ◽  
Large Scale ◽  
Qr Decomposition ◽  
Decomposition Algorithm ◽  
Wireless Technology ◽  
Multiuser Mimo ◽  
Downlink Transmission ◽  
High Data ◽  
Mimo Downlink

MIMO is a wireless technology that uses large scale antennas to transfer more data at the same time and to increase spectral efficiency. To achieve high data rate with less bandwidth we use decomposition algorithm. Among various de-composition algorithm QR decomposition algorithm outperforms low bit error rate(BER), but the computational complexity is prohibitively high when the system incorporates large number of antennas. This paper presents a low computational sorted QR decomposition (SQRD) algorithm for MIMO.SQRD uses precoding technique at the transmitter which decomposes the channel that can sent in parallel.

Improving Energy Efficiency and Throughput in Heterogeneous Mobile Ad Hoc Networks

2011 ◽  
pp. 37-49
Author(s):  
Manu J. Pillai ◽  
M. P. Sebastian
Keyword(s):  
Ad Hoc ◽  
Transmission Rate ◽  
Mac Protocol ◽  
Signal Loss ◽  
High Data ◽  
Communication Links ◽  
Adhoc Networks ◽  
Simulation Results ◽  
Demand Routing ◽  
Hoc Networks

The nodes are expected to transmit at different power levels in heterogeneous mobile adhoc networks, thus leading to communication links of different length. Conventional MAC protocols that unconditionally presume that links are bi-directional and with unvarying energy distribution may not succeed or execute badly under such circumstances. Interference and signal loss resulting out of distance and fading diminish the entire throughput attained in heterogeneous networks to a greater extent. This article presents a MAC protocol, which adaptively transmits data frames using either the energy efficient nodes or a list of high data rate assistant nodes. In addition, a cross-layer based energy level on-demand routing protocol that adaptively regulates the transmission rate on basis of congestion is projected as well. Simulation results illustrate that the proposed protocols considerably diminish energy consumption and delay, and attain high throughput in contrast with the Hybrid MAC and traditional IEEE 802.11 protocols

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