31,735 research outputs found
Optimal Power Allocation for Integrated Visible Light Positioning and Communication System with a Single LED-Lamp
In this paper, we investigate an integrated visible light positioning and
communication (VLPC) system with a single LED-lamp. First, by leveraging the
fact that the VLC channel model is a function of the receiver's location, we
propose a system model that estimates the channel state information (CSI) based
on the positioning information without transmitting pilot sequences. Second, we
derive the Cramer-Rao lower bound (CRLB) on the positioning error variance and
a lower bound on the achievable rate with on-off keying modulation. Third,
based on the derived performance metrics, we optimize the power allocation to
minimize the CRLB, while satisfying the rate outage probability constraint. To
tackle this non-convex optimization problem, we apply the worst-case
distribution of the Conditional Value-at-Risk (CVaR) and the block coordinate
descent (BCD) methods to obtain the feasible solutions. Finally, the effects of
critical system parameters, such as outage probability, rate threshold, total
power threshold, are revealed by numerical results.Comment: 13 pages, 14 figures, accepted by IEEE Transactions on Communication
Robust Power Allocation for Integrated Visible Light Positioning and Communication Networks
Integrated visible light positioning and communication (VLPC), capable of
combining advantages of visible light communications (VLC) and visible light
positioning (VLP), is a promising key technology for the future Internet of
Things. In VLPC networks, positioning and communications are inherently
coupled, which has not been sufficiently explored in the literature. We propose
a robust power allocation scheme for integrated VLPC Networks by exploiting the
intrinsic relationship between positioning and communications. Specifically, we
derive explicit relationships between random positioning errors, following both
a Gaussian distribution and an arbitrary distribution, and channel state
information errors. Then, we minimize the Cramer-Rao lower bound (CRLB) of
positioning errors, subject to the rate outage constraint and the power
constraints, which is a chance-constrained optimization problem and generally
computationally intractable. To circumvent the nonconvex challenge, we
conservatively transform the chance constraints to deterministic forms by using
the Bernstein-type inequality and the conditional value-at-risk for the
Gaussian and arbitrary distributed positioning errors, respectively, and then
approximate them as convex semidefinite programs. Finally, simulation results
verify the robustness and effectiveness of our proposed integrated VLPC design
schemes.Comment: 13 pages, 15 figures, accepted by IEEE Transactions on Communication
Five Facets of 6G: Research Challenges and Opportunities
Whilst the fifth-generation (5G) systems are being rolled out across the
globe, researchers have turned their attention to the exploration of radical
next-generation solutions. At this early evolutionary stage we survey five main
research facets of this field, namely {\em Facet~1: next-generation
architectures, spectrum and services, Facet~2: next-generation networking,
Facet~3: Internet of Things (IoT), Facet~4: wireless positioning and sensing,
as well as Facet~5: applications of deep learning in 6G networks.} In this
paper, we have provided a critical appraisal of the literature of promising
techniques ranging from the associated architectures, networking, applications
as well as designs. We have portrayed a plethora of heterogeneous architectures
relying on cooperative hybrid networks supported by diverse access and
transmission mechanisms. The vulnerabilities of these techniques are also
addressed and carefully considered for highlighting the most of promising
future research directions. Additionally, we have listed a rich suite of
learning-driven optimization techniques. We conclude by observing the
evolutionary paradigm-shift that has taken place from pure single-component
bandwidth-efficiency, power-efficiency or delay-optimization towards
multi-component designs, as exemplified by the twin-component ultra-reliable
low-latency mode of the 5G system. We advocate a further evolutionary step
towards multi-component Pareto optimization, which requires the exploration of
the entire Pareto front of all optiomal solutions, where none of the components
of the objective function may be improved without degrading at least one of the
other components
Introduction to indoor networking concepts and challenges in LiFi
LiFi is networked, bidirectional wireless communication with light. It is used to connect fixed and mobile devices at very high data rates by harnessing the visible light and infrared spectrum. Combined, these spectral resources are 2600 times larger than the entire radio frequency (RF) spectrum. This paper provides the motivation behind why LiFi is a very timely technology, especially for 6th generation (6G) cellular communications. It discusses and reviews essential networking technologies, such as interference mitigation and hybrid LiFi/Wi-Fi networking topologies. We also consider the seamless integration of LiFi into existing wireless networks to form heterogeneous networks across the optical and RF domains and discuss implications and solutions in terms of load balancing. Finally, we provide the results of a real-world hybrid LiFi/Wi-Fi network deployment in a software defined networking testbed. In addition, results from a LiFi deployment in a school classroom are provided, which show that Wi-Fi network performance can be improved significantly by offloading traffic to the LiFi
Light-Fidelity as Next Generation Network Technology: A Bibliometric Survey and Analysis
This paper delivers a systematic review and a bibliometric survey analysis of Light-Fidelity (Li-Fi) indoor implementation in Next Generation Network (NGN). The main objective of this study is to design a communication network based on NGN-Li-Fi for the indoor implementation which aims to increase user Quality of Service (QoS). The main merits and contributions of this study are the thorough and detailed analysis of the review, both in literature surveys and bibliometric analysis, as well as the discussion of the implementation model challenges of Li-Fi in both indoor and outdoor environments. The issue articulated in an indoor communication network is the possibility of intermittent connectivity due to barriers caused by line-of-sight (LOS) between the LED transmitter and receiver, handover due to channel overlap, and other network reliability issues. To realize the full potential and significant benefits of the Next Generation Network, challenges in indoor communication such as load-balancing and anticipating network congestion (traffic congestion) must be addressed. The main benefit of this study is the in-depth investigation of surveys in both selected critical literatures and bibliometric approach. This study seeks to comprehend the implications of Next Generation networks for indoor communication networks, particularly for visible light communication channels
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