Visible light communications heterogeneous network (VLC-HetNet): new model and protocols for mobile scenario

Integrating visible light communication (VLC) with conventional radio frequency (RF)-enabled wireless networks has been shown to improve the achievable data rates of mobile users. This paper provides a stochastic geometry framework to perform the coverage and rate analysis of a typical user in co-existing VLC and RF networks covering a large indoor area. The developed framework can be customized to capture the performance of a typical user in various network configurations such as (i) RF-only, in which only small base-stations (SBSs) are available to provide the coverage to a user, (ii) VLC-only, in which only optical BSs (OBSs) are available to provide the coverage to a user, (iii) opportunistic RF/VLC, where a user selects the network with maximum received signal power, and (iv) hybrid RF/VLC, where a user can simultaneously utilize the available resources from both RF and VLC networks. The developed model for VLC network precisely captures the impact of the field-of-view (FOV) of the photo-detector (PD) receiver on the number of interferers, distribution of the aggregate interference, association probability, and the coverage of a typical user. Closed-form approximations are presented for special cases of practical interest and for asymptotic scenarios such as when the intensity of SBSs becomes very low. The derived expressions enable us to obtain closed-form solutions for various network design parameters (such as intensity of OBSs and SBSs, transmit power, and/or FOV) such that the number of active users can be distributed optimally among RF and VLC networks. Also, we optimize the network parameters in order to prioritize the association of users to VLC network. Finally, simulations are carried out to verify the derived analytical solutions. It is shown that the performance of VLC network depends significantly on the receiver's FOV/intensity of SBSs/OBSs and careful selection of such parameters is crucial to harness the benefits of VLC networks. Important trade-offs between height and intensity of OBSs are highlighted to optimize the performance of a user in VLC networks. Multi-cell downlink visible light communication (VLC) networks, rate coverage probability, fieldof-view, traffic load distribution, Poisson Point Process (PPP). optical signals do not interfere with the RF electronic systems and can be used in sensitive areas such as hospitals [8] and aircrafts henceforth. Contrary to RF, VLC is susceptible to indoor blockages (walls, human, material objects, etc.) thus naturally confined to a small area. The received power at PD depends heavily on the line of sight (LoS) signals that may get blocked due to limited field-of-view (FOV) of the PD receivers, and/or radiance angle of the optical LEDs. As such, the dense deployment of LEDs may not guarantee a reliable coverage. VLC is thus considered as a complimentary rather than substituting technology to RF [9]-[11]. A. Background Work Recently, few research proposals have investigated the performance of hybrid RF/VLC systems [12]-[15]. In [12], energy effici...

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“…where R s and R o can be given using (16) and (17) with the modification of taking expectation over X s and X o instead of V and R, respectively.…”

Section: ) Average Spectral Efficiencymentioning

confidence: 99%

Coverage and Rate Analysis for Co-Existing RF/VLC Downlink Cellular Networks

Tabassum

Hossain

2018

IEEE Trans. Wireless Commun.

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“…They proposed a scheme to determine whether to perform VHO given the queue length and the condition of the optical channel. A novel VLC-HetNet protocol was proposed in [5,6] that combined access, horizontal, and vertical handover mechanisms for a mobile terminal (MT) to resolve user mobility among different hotspots and an OFDMA system. The simulation results showed improvements in the capacity performance of the VLC-HetNet compared to that of the RF system.…”

Section: Related Workmentioning

confidence: 99%

“…In recent years, a VLC heterogeneous network (VLC-HetNet) was found to be backing both VLC and orthodox RF system that combines the advantages of VLC and RF technology [4][5][6]. The constraints of the VLC are due to its susceptibility to LOS transmissions.…”

Section: Introductionmentioning

confidence: 99%

A QoE-maximization-based vertical handover scheme for VLC heterogeneous networks

Bao

Adjardjah

Okine

et al. 2018

J Wireless Com Network

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Visible light communication (VLC), not only provides indoor illumination, but also offers broadband connection. It has the benefits of huge bandwidth, high security, low cost, and health safety. However, duplex communication, user mobility, and seamless coverage are becoming challenging tasks in VLC networks. A VLC heterogeneous network (VLC-HetNet) that combines VLC and existing radio networks, in which a good vertical handover (VHO) scheme is critical to guarantee continuous transmission, has been proposed to solve these problems. In this paper, we propose a new VHO scheme to maximize the quality of experience (QoE) of a user. When a user makes a handover between VLC and the RF network, the influence on the user's QoE may be positive (defined as the QoE profit) or negative (the reduced QoE value is defined as the handover cost). The handover decision is made in order to enhance the QoE and reduce the handover cost of the user, by formulating the problem as a Markov decision process (MDP). The simulation results show that the proposed VHO scheme is adaptive to user movement and achieves a relatively high average QoE, low handover failure probability, and few handover times.

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“…However, the limitation in the coverage of VLC is a drawback. By combining VLC and WiFi, we can have a hybrid communication network that offers high wireless capacity and dependable mobile connectivity [7]. To achieve this feat, the critical issue of vertical handover (VHO) from one network to the other has to be addressed.…”

Section: Introductionmentioning

confidence: 99%

Channel adaptive dwell timing for handover decision in VLC-WiFi heterogeneous networks

Bao

Okine

Adjardjah

et al. 2018

J Wireless Com Network

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The coexistence of visible light communication (VLC) and WiFi elevates indoor wireless communications beyond 4G, by utilizing VLC for high-rate transmission and ensuring reliable mobile connectivity through WiFi. Nevertheless, the high susceptibility of VLC-line-of-sight (VLC-LoS) channel to blocking can result in excessive number of handovers between VLC and WiFi networks leading to huge signaling cost and degradation in overall system performance. Therefore, an efficient inter-system handover scheme is required for a successful integration of the two access technologies. To this end, a channel adaptive dwell vertical handover (CAD-VHO) scheme is presented, in this article, as an improvement on static D-VHO scheme. The width of the dwell timer employed in our scheme is altered based on the rate of blocking and recovery of VLC-LoS channel. As a result, the proposed CAD-VHO scheme is adaptive to the rate and extent of obstruction of VLC-LoS link due to user mobility and surrounding objects. Simulation scenario was set up as a dynamic network environment in an indoor setting with restless and stationary mobile terminals and surrounding mobile object. Based on the simulation results obtained, the CAD-VHO scheme can reduce the number of VHOs by as much as 80% whiles achieving a higher average data rate in most cases. Consequently, the proposed CAD-VHO scheme is highly efficient in minimizing VHO signaling cost and enabling a superior broadband service.

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Visible light communications heterogeneous network (VLC-HetNet): new model and protocols for mobile scenario

Cited by 23 publications

References 17 publications

Coverage and Rate Analysis for Co-Existing RF/VLC Downlink Cellular Networks

Coverage and Rate Analysis for Co-Existing RF/VLC Downlink Cellular Networks

A QoE-maximization-based vertical handover scheme for VLC heterogeneous networks

Channel adaptive dwell timing for handover decision in VLC-WiFi heterogeneous networks

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