NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract Session 2532 On-line Engineering Laboratories: Real-Time Control Over the Internet Christophe Salzmann1, Denis Gillet1, Haniph A. Latchman2, and Oscar D. Crisalle2 1 Swiss Federal Institute of Technology, Lausanne, Switzerland/ 2 University of Florida, Gainesville, Florida Abstract The advent of the Internet as a major communication channel has triggered a great deal of interest in real-time communication over packet-switched networks. While store and forward networks such as the Internet were not originally designed to handle real-time traffic, now that this global communication infrastructure exists and is becoming ubiquitous. Computer-based hardware and software subsystems are being designed to transport such real-time services as broadcast audio and video (live or via various streaming media technologies) and even interactive audio and video services. In this paper we propose another step ahead into the realm of remote real-time control over the Internet. We demonstrate the feasibility of using a distributed on-line laboratory to complement and enhance traditional and on-line courses in Control Engineering. It is shown that the distributed laboratory readily enables students to conduct real-time experimental studies and that it is also suitable for live in-class demonstrations. The proposed design is presented as a paradigm for analogous developments in other courses requiring a laboratory component.

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In the literature, the majority of research efforts in power line communication (PLC) has been focused on the physical layer in order to deal with issues such as the time varying behavior of loads in electric power systems, the presence of high power impulsive noise, the occurrence of impedance mismatching, the widespread use of unshielded power cables, and the existence of coupling losses. While some works have also been carried out on the PLC medium access control (MAC) sublayer, there are scopes for further research to address the novel demands associated with cyber physical systems that need to mitigate unfairness in resource sharing, collisions and starvation, among other issues which may degrade data communication quality. In this paper, we provide a comprehensive survey regarding the state-of-the-art of MAC protocols for PLC systems, including an overview of existing PLC MAC research results and an organization of current PLC MAC protocols in terms of type of protocols, applications, and main research focus. Moreover, we present modern PLC technologies and standards, highlighting their MAC sublayer characteristics and providing a detailed comparative analysis of PLC MAC protocols in the context of current and emerging PLC applications. Finally, we identify future trends within the scope of the MAC sublayer for PLC systems with a view to stimulating additional research efforts on PLC MAC design.

Increasing deployment of information technologies and low-inertia renewable energy sources into smart grid fuel the uncertainties and reveal security and transient stability problems. Enhancing the stability margins of smart grids despite the cyber and physical disturbances emerges the need for cyber-aware robust controller design. Therefore, a distributed nonlinear robust controller is proposed to improve the transient stability margins of synchronous generators (SG) in the presence of excessive communication delay and cyber-physical disturbances. The proposed controller uses phasor measurement units to receive real-time measurements and actuates distributed storage systems to inject or absorb power in order to accelerate stabilization of frequency oscillations of SG following a disturbance. The communication dependency exposes time delay and cyber-security issues since latency is inherent and can be excessive during an attack such as denial of service. In addition, uncertainties in measurements challenge the stabilization process. Hence, the proposed controller is designed for robustness to delay and additive disturbances. A novel time delay compensation technique is developed to inject delay-free control signal into the closed-loop system. To guarantee that all tracking error signals are globally uniformly ultimately bounded, novel Lyapunov-Krasovskii functionals are used in the Lyapunov-based stability analysis. The simulation results validate the feasibility of the proposed control framework and robustness under cyber-physical practical limitations.

Transient stability of power systems has become even more critical due to increasing complexity created by large penetration of renewable energy sources and massive deployment of information and communication technology. Fortunately, the two-way real-time data exchange capacity of smart grids allows designing advanced digital control schemes to better address the power system stability. In this study, a non-linear model-free-based robust controller in conjunction with a state estimation architecture is designed to enhance transient stability margins. The designed controller addresses uncertainties arising from communication and control input delay, sensor errors, varying plant parameters, and unmodelled dynamics effects. A novel time-delay compensation technique is presented in the control development to mitigate the effect of delay and the robustness of the proposed controller is proven by conducting a Lyapunov stability analysis with respect to additive disturbance and time delay. Furthermore, the proposed control framework is validated on the IEEE 39 bus test system through MATLAB simulation. The results show that the proposed framework is capable of stabilising the power system after a fault, also showing robustness to noise, latency in communication, delay in control input, and malicious data injection.

This work introduces a novel resource allocation technique for dealing with linear and periodically time‐varying power line channels when an orthogonal frequency division multiplexing scheme is applied. By exploiting the correlations within one cycle of the mains signal, among cycles of mains signal and a combination of these connections, the proposed technique can offer three distinct trade‐offs between computational complexity reduction and data‐rate loss. Numerical results, which are based on measured data, are used to analyse these trade‐offs, when these inter‐cycle and intra‐cycle relationship are taken into account. Also, we verify that the use of the normalised signal‐to‐noise ratio incurs very low performance degradation, and because of computational complexity rationale, its use is strongly recommended. Additionally, we show that those cases, in which the correlations among the cycles of the mains signal is relevant, offer the best trade‐off between computational complexity reduction and data‐rate loss. Finally, we show that the proposed technique can achieve the optimal data‐rate and offers substantial improvements in terms of computational complexity when compared with existing approaches, including the Institute of Electrical and Electronics Engineers 1901 standard. Copyright © 2015 John Wiley & Sons, Ltd.

Mobility management is an essential challenge for supporting reliablemultimedia data streaming overwireless and mobile networks in the Internet of Things (IoT) for location-based mobile marketing applications. The communications among mobile nodes for IoT need to have a seamless handover for delivering high quality multimedia services. The Internet Engineering Task Force (IETF) mobility management schemes are the proposals for handling the routing of IPv6 packets to mobile nodes that have moved away from their home network. However, the standard mobility management scheme cannot prevent packet losses due to longer handover latency. In this article, a new enhanced data streaming route optimization scheme is introduced that uses an optimized Transmission Control Protocol (TCP) realignment algorithm in order to prevent the packet disordering problem whenever the nodes in the IoT environment are communicating with each other. With the proposed scheme, data packets sequence realignment can be prevented, the packet traffic speed can be controlled, and the TCP performance can be improved. The experimental results show that managing the packet order in proposed new scheme remarkably increases the overall TCP performance over mobile networks within the IoT environment thus ensuring the high quality of service (QoS) for multimedia data streaming in locationbased mobile marketing applications.

In this paper, we present a decentralized nonlinear robust controller to enhance the transient stability margin of synchronous generators. Although, the trend in power system control is shifting towards centralized or distributed controller approaches, the remote data dependency of these schemes fuels cyber-physical security issues. Since the excessive delay or losing remote data affect severely the operation of those controllers, the designed controller emerges as an alternative for stabilization of Smart Grids in case of unavailability of remote data and in the presence of plant parametric uncertainties. The proposed controller actuates distributed storage systems such as flywheels in order to reduce stabilization time and it implements a novel input time delay compensation technique. Lyapunov stability analysis proves that all the tracking error signals are globally uniformly ultimately bounded. Furthermore, the simulation results demonstrate that the proposed controller outperforms traditional local power systems controllers such as Power System Stabilizers.

This work focuses on analyses of cooperative protocols to enhance the performance of power line communication systems. Based on a measurement campaign and considering a sum power constraint, achievable data rates for amplify-and-forward (AF) and decode-and-forward (DF) protocols are analyzed. Similar investigations are performed for the maximum data rates attained using Hermitian-symmetric orthogonal frequency division multiplexing (HS-OFDM) together with equal gain combining (EGC), selection combining (SC) and maximal ratio combining (MRC) techniques. The influences of optimally and uniformly allocated transmission power and frequency bandwidth are are also analyzed and the efficiency of combination before and after equalization is compared. Results show that the relative distances among source, relay and destination nodes significantly impact system performance. Also, they reveal a range of total transmission power and bandwidth in which benefits can be verified. Among combining techniques, MRC and SC present similar results, but MRC offers a slightly better performance. In relation to computational complexity, SC is the most favorable. Maximum data rate analyses of HS-OFDM with frequency domain equalization based on zero forcing and minimum mean square error criteria show that the former scheme offers almost the same performance as the latter. Furthermore, it is shown that equalization after combination is more advantageous.

This work focuses on the characterization of indoor hybrid power line communication (PLC)-wireless channels in the frequency band between 1.7 and 100 MHz. These hybrid channels allow the simultaneous exploitation of the ubiquitous PLC channel and the mobility benefits offered by the wireless signals radiating from and being induced into power cables. A comprehensive study and analysis was conducted based on: (i) coherence time, (ii) additive-noise power spectral density, (iii) coherence bandwidth, (iv) delay spread, (v) average channel gain, (vi) channel frequency response and (vii) channel capacity. Based on the reported analysis, the magnitude responses of hybrid PLC-wireless channels can be assumed to be symmetrical and significantly frequency selective. Also, we reveal that additivenoise power spectral density and, consequently, channel capacity differ considerably in the PLC-to-wireless and wireless-to-PLC transmission directions. Finally, we show that the measured PLCwireless channels present a channel capacity of up to hundreds mega bits per second.

Power Line Communication (PLC) has become an integral part of home area networks (HANs) with increasing deployment of intelligent and connected devices. The advent of smart devices creates a heterogeneous type of network with a variety of throughput and delay sensitive applications that must coexist in the HAN. Meeting the quality of service (QoS) for various applications requires high MAC throughput, low channel access delay and prioritized channel access for certain types of data. The Medium Access Control (MAC) protocol for PLC, defined in HomePlug and IEEE 1901, exhibits significant degradation in MAC throughput and increasing channel access delay when the number of users increases. PLC MAC layer issues have received relatively modest attention of researchers compared with physical layer problems and as a result relatively little improvement in MAC throughput and delay performance has been reported over the standard IEEE 1901 protocol. This paper studies an adaptive contention window PLC MAC protocol with a view to assessing access delay performance of this modified protocol, with the throughput and prioritized traffic classes. In the adaptive protocol, each node observes the channel status and adaptively finds the optimum contention window size. Results demonstrate a significant improvement in both MAC efficiency and access delay for the highest priority class in the presence of lower priority classes. Whereas the MAC efficiency drops down to 10% in standard protocols, the proposed adaptive MAC protocol retains its efficiency at about 81% for up to 100 users. Also, the channel access delay is for the modified protocol is maintained under 200 ms for 100 users compared to more than 1000 ms for the standard HomePlug MAC.

This chapter provides a description of innovative PLC multimedia communication technologies that provide acceptable levels of latency, jitter and reliability for the delivery of multimedia content via noisy and unreliable power line channels. Only the details of the Physical Layer Convergence Protocol (PLCP) that describe the MAC-PHY interface for the IEEE 1901 FFT-OFDM PLCP are explained in the chapter. Performance of the two-level framing approach, independent of the MPDU and channel access overheads, was presented. The chapter summarizes those results and then provide the results of detailed simulations based on measured PHY characteristics and known MAC parameters. It focuses on the key enhancements of HomePlug AV2, namely, MIMO, an extended frequency band, Short Delimiter, Delayed Acknowledgement, Effective Notching, and Immediate Repeating. External threat implies an attacker capable of eavesdropping on transmissions and sending frames within the network, but out of network access credentials.

HomePlug Green PHY (HPGP), designed to address the needs of Smart Grids, uses the carrier sense multiple access with collision avoidance (CSMA/CA) scheme to define its multiple access control (MAC). Similar to the IEEE 802.11, the MAC efficiency of HPGP protocol degrades when the number of users increases. This paper examines a comprehensive high-load simulation of the IEEE 802.11 DCF backoff mechanism, compares the performance of this mechanism with the performance of P1901/HomePlug MAC, and introduces a constant contention window MAC - a novel MAC protocol that maximizes efficiency in a heavily-loaded smart grid environment. In the proposed MAC protocol, every node generates a run-time channel traffic estimation and an adaptive contention window size adjustment. We demonstrate that, whereas the HPGP's MAC efficiency drops down to about 15%, the proposed adaptive MAC protocol retains its efficiency at about 81% with up to 100 users.

Due to the increasing cost effectiveness of solar panels, the growing demand for renewable energy sources, and the U.S. government's financial support, the adoption of solar energy has soared in the past few years. According to the PV Market Report, presented by the European Photovoltaic Industry Association, the cumulative installed capacity of photovoltic (PV) systems around the world rose from ...

This paper focuses on a novel bit loading technique that is capable of reducing the computational complexity associated with the resource allocation in power line communication (PLC) system based on orthogonal frequency division multiplexing (OFDM) scheme. Basically, the proposed technique exploits the existing connection among microslots within one cycle and/or among consecutive cycles of the mains signal to trade computational complexity with data-rate when the channel is periodically time varying. Numerical results, which are based on measured data set, reveal considerable computational complexity savings with low probability of data-rate loss ratio and, as a consequence, the proposed technique can be useful to reduce hardware resource utilization in PLC transceiver based on OFDM scheme for in-home scenario.

Turbo codes are attractive compared with Low Density Parity Check (LDPC) codes for Forward Error Correction (FEC) applications mainly due to their superior performance, especially at low Signal-to-Noise Ratio (SNR) such as are common in Powerline channels. For example, IEEE 1901-FFT PHY used the Turbo coding scheme defined in the HomePlug AV standards. However, patent fees are usually required for each turbo-code enabled manufactured device. The objective of this paper is to examine whether unlicensed LDPC codes, with optimized choices of block lengths, could be a viable alternative for future Powerline Communications (PLC) applications. The paper shows that the performance of the LDPC codes can approximate that of the Turbo codes with higher block lengths, on channels with typical and realistic PLC characteristics. The paper also shows that the additional complexity associated with this increase in block length can be mitigated by the use of Quasi-Cyclic LDPC (QC-LDPC) codes.

The HomePlug AV PHY and MAC Layers were jointly designed to address the unique properties and challenges of powerline channels. Various problems are addressed to communicate reliably on the powerline medium at data rates relatively close to capacity and with Quality of Service (QoS) guarantees. For example, the framing and segmentation process in HomePlug AV was tied directly to the Forward Error Correction coding (FEC) and channel interleaving so that only the portion of frames that experienced decoding failure need to be retransmitted. Another example is that the HomePlug AV MAC Beacon Period was defined to be synchronous to the powerline frequency to facilitate, among other things, being able to support different bit-loading maps for different phases of the AC powerline cycle. The chapter provides details on the power line communication (PLC) channel characteristics and the solutions adopted in HomePlug AV to address them. Controlled Vocabulary Terms carrier transmission on power lines; communication channels; forward error correction; home networks; media access protocol

Broadband powerline communication systems are continuing to gain significant market adoption worldwide for applications ranging from high speed multimedia to Smart Grid applications. HomePlug AV is the most successful high speed PLC protocol and in fact was adopted as a major component of the IEEE 1901 standard. This paper provides an overview of the unique design choices made in the development of the MAC and PHY subsystems of HomePlug AV and describes how these capabilities were adapted and augmented for incorporation into the IEEE 1901 Standard. The paper also discusses an example of IEEE 1901 used as a Smart Grid enabler. The paper then proceeds to explain how HomePlug AV was adapted to form the recently released HomePlug Green PHY specification that uses robust HomePlug AV communication modes at 10 Mbps for Smart Energy applications. Finally the paper shows how HomePlug AV was augmented and enhanced to produce HomePlug AV 2.0 using MIMO and other capabilities to achieve speeds of up to 1.5 Gbps.

The MAC Protocol Data Unit (MPDU) consists of information that is exchanged between the MAC and the Physical (PHY) layers. When the MAC Layer needs to communicate information with one or more peer-MAC Layers, it generates an MPDU. This chapter provided a description of the structure and operation of the HomePlug AV MAC protocol Data Unit, and explained the formats used for key delimiters (such as SOF and RTS/CTS) as well as the Beacon, Sound, and Data MPDUs. Beacon MPDUs play an important role in network management, controlling channel access and topology discovery. The Start-of-Frame (SOF) MPDU provides the primary means for stations to exchange data and management information. Request to Send (RTS) and Clear to Send (CTS) are primarily intended to handle hidden station within the network. The selective acknowledgment (SACK) Frame Control fields is divided into groups based on the functionality they support. Controlled Vocabulary Terms home networks; media access protocol