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Visible-light-based transmission application plays an important role in various types of sensor services for the Internet of Things (IoTs). However, in big data scenarios, current visible-light-based systems cannot achieve concurrent high-speed communication, low-speed communication, and positioning. Therefore, in this article, we propose a smart visible-light-based fusion applications system, named Fasys, to solve the above problem for the big data traffic with heterogeneity. Specifically, for low-speed data services, we propose a novel linear block coding and bit interleaving mechanism, which enhances the LED positioning accuracy and recovers the lost data bits in the interframe gap (IFG). For high-speed data services with traffic possessing burstiness, an elegant statistical reliability analysis framework in regard to latency is proposed based on martingale theory. The backlog martingale process is constructed. Leveraging stopping time theory, a tight upper bound of unreliability is obtained. An arrival abstraction and traffic allocation scheme is designed, which contributes to decouple the reliability requirement as the maximum supportable arrival load. Finally, we implement our Fasys system, and extensive experimental results show that our system can achieve consistent high-precision positioning and low-BER data communication for low-speed data services. And the proposed martingale-based traffic allocation scheme can achieve the provisioning of reliability in regard to the latency for high-speed data services. [ABSTRACT FROM AUTHOR]

With the rapid development of smart cities, white light-emitting diodes (LEDs) are widely used in indoor lighting due to their characteristics of energy-saving, long lifetimes, and low cost. At the same time, the high-frequency modulated LEDs allow visible light to be used for indoor communications, positioning, and security. Visible light applications have many advantages, such as avoiding electromagnetic interference, high communication speed, great privacy, and high-precise positioning. In this paper, we will survey the application prospects and research results of visible light from scenarios such as high-speed communication, privacy security, and navigation localization and focus on analyzing and discussing the challenges and development trends encountered in visible light positioning. [ABSTRACT FROM AUTHOR]

The virtualization of both servers and substrate networks is a promising technique that will enable the future Internet architecture to support a variety of cloud computing services and architectures. The problem of efficiently mapping a virtual infrastructure (VI) over a wide-area optical network is a key problem in provisioning Infrastructure (and Network) as a Service over multiple datacenters. In this paper, we study the problem of cost efficient VI mapping and propose a novel approach called the virtual infrastructure mapping algorithm (VIMA) that jointly considers node mapping and link mapping. Such a close coordination between the link and node mapping stages increases the efficiency of the VIMA algorithm. We compare the performance of our VIMA algorithm with other VI mapping algorithms such as NSVIM, vnmFlib and R-ViNE under various performance metrics using simulation. Our simulation results and analysis show that the VIMA algorithm outperforms the other algorithms in terms of VI mapping costs and path length of VI links. [ABSTRACT FROM AUTHOR]

Abstract: In optical networks, with the number of wavelengths in fibers increasing, the size and cost of Optical Cross-Connects (OXC) have been increased. Waveband merging technology, which groups several wavelength routes into a single waveband tunnel with at least two hops, could perform port-cost savings by reducing the size and cost of OXC since switching one waveband in the All Optical (OOO) domain only consumes two ports at each bypass node. On the other hand, the absence of wavelength conversion restricts the capability of OOO–OXC. Therefore, designing a hybrid hierarchical node to transmit wavebands in an OOO switch and add/drop local requests or perform wavelength conversion in an Optical-Electrical-Optical (OEO) switch has been one of the promising solutions for next-generation optical networks. However, due to the increasing effects of greenhouse gases and the drastic consumption of power, port-cost and power-consumption savings are becoming the new and twin objectives to further develop hybrid hierarchical optical networks. In this paper, we jointly consider port-cost and power-consumption in a hybrid hierarchical optical network and propose efficient approaches including Integer Linear Programming (ILP) models and heuristics. Simulation results of two heuristic approaches, a Cost and Power savings algorithm based on an End-to-End waveband Merging strategy (CPEEM) as well as a Cost and Power savings algorithm based on a Sub-Path waveband Merging strategy (CPSPM), show that the cost of Transmitting Ports (TPs) used in an OOO switch is in contrast to the use of the power consumed by the OEO part of a hybrid hierarchical node. Moreover, comparing with CPEEM, CPSPM has a better performance for port-cost savings but the performance improvement is at the cost of higher power consumption in an OEO switch. On the contrary, CPEEM has a better performance for power-consumption savings but the performance improvement is achieved at the expense of a higher cost of transmitting ports comparing with CPSPM. Based on the parameter, Boundary of Consumed Power (BCP), a New Integrated Algorithm (NIA) that could effectively choose between CPEEM or CPSPM according to the current network state is proposed to obtain the trade-off performances. [Copyright &y& Elsevier]

The exponential growth of the demand for broadband services has imposed great challenges on the design of spectrum-efficient optical transmission system in Passive Optical Network (PON). Recently, an innovative Orthogonal Frequency Division Multiplexing (OFDM) scheme, called Polar-OFDM (P-OFDM), has emerged as a promising solution to boost the spectral efficiency of optical transmission in PON. However, the traditional P-OFDM does not yet perform best in spectral efficiency as it only uses half of the total subcarriers. In this paper, we verify a promising complementation between Polarization Multiplexing (POLMUX) and P-OFDM aiming at higher spectral efficiency. We then propose the full-subcarriers P-OFDM by loading data on the even-indexed subcarriers of X polarization and the odd-indexed subcarriers of Y polarization, respectively. Thus, all of the subcarriers will be utilized for effective data transmission, which can double the spectral efficiency. More importantly, because the subcarriers are interlaced on different polarizations, the cross-polarization interference can be significantly mitigated, which enables the independent channel estimation and equalization at the receiver to recover the data carried on each polarization. Our evaluation results demonstrate that the proposed system realizes the double spectral efficiency of the traditional P-OFDM with reasonable Bit Error Rate (BER) performance loss. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we propose a novel robust routing algorithm based on Valiant load-balancing under the model of polyhedral uncertainty (i.e., hose uncertainty model) for WDM (wavelength division multiplexing) mesh networks. Valiant load-balanced robust routing algorithm constructs the stable virtual topology on which any traffic patterns under the hose uncertainty model can be efficiently routed. Considering there are multi-granularity connection requests in WDM mesh networks, we propose the method called hose-model separation to solve the problem for the proposed algorithm. Our goal is to minimize total network cost when constructing the stable virtual topology that assures robust routing for the hose model in WDM mesh networks. A mathematical formulation (integer linear programming, ILP) about Valiant load-balanced robust routing algorithm is presented. Two fast heuristic approaches are also proposed and evaluated. We compare the network throughput of the virtual topology constructed by the proposed algorithm with that of the traditional traffic grooming algorithm under the same total network cost by computer simulation. [Copyright &y& Elsevier]