Boosting powerline communications for ubiquitous connectivity in enterprises

As powerline communication (PLC) technology does not require dedicated cabling and network setup, it can be used to easily connect multitude of IoT devices deployed in enterprise environments for sensing and control related applications. IEEE has standardized the PLC protocol in IEEE 1901, also known as HomePlug AV (HPAV) which has been widely adopted in mainstream PLC devices. A key weakness of HPAV protocol is that it does not support spectrum sharing. Currently, each link in an HPAV PLC network operates over the whole available spectrum, and only one link can operate at any time within a single collision domain. In this work, through an extensive measurement study of HPAV PLCs in a real enterprise environment using commodity off-the-shelf (COTS) HPAV PLC devices, we discover that spectrum sharing can significantly benefit enterprise level PLC networks. To this end, we propose a distributed spectrum sharing technique for enterprise HPAV PLC networks, and show that fine-grained distributed spectrum sharing on top of current HPAV MAC protocols can significantly boost the aggregated and per-link throughput, by allowing multiple PLC links to communicate concurrently, while requiring only a few modifications to the existing HPAV devices and protocols.

The hybrid wireless and power line communication (PLC) technology greatly improves the reliability of Power Internet of Things network (IoT) and the access ability of the terminals. However, with the development of Power IoT, the topology structure of the network becomes exceedingly complex, and the difficulty of networking is also gradually increasing. To address this issue, this paper proposes a multi-ant colony (MACS) based QoS networking algorithm for hybrid PLC and wireless communication networks. Considering the network QoS parameters and service demands, the networking algorithm constructs the fitness function to evaluate the quality of communication transmission paths, and the MACS algorithm is employed to establish the optimal relay route to complete networking. Numerical results prove that the MACS algorithm has a superior ability to jump out of local optimum than the traditional improved ant colony system (IACS) algorithm. Moreover, our proposed algorithm can construct the optimal relay route under corresponding constraints and demands according to different types of services.

Power line communication (PLC) technology has created a niche use in the Internet of Things (IoT) by offering flexible and reliable connection among power-driven IoT devices/sensors over existing wired networks. In IoT over PLC networks, massive real-time data generated by the ever-growing connected devices will eventually pose an overwhelming burden on the IoT cloud, which in turn severely degrades the network performance. To cope with these issues, edge computing (EC) has emerged as a complement to cloud computing, aiming at offloading a portion of computing in the cloud to the network edges closer to the IoT devices. However, confronting a practical scenario that some electrical devices cannot communicate with wireless and mobile networks directly, existing EC paradigms may not be directly applied to IoT over PLC networks. In this paper, we propose a novel EC-IoT over PLC paradigm to reduce the transmission latency while migrating a portion of computing from the cloud to the edges. First, we develop a distributed EC platform to serve terminal users (TUs) in different IoT systems with various IoT services. Second, we put forth a cache-enabled scheme to store the popular contents from the cloud and edge sensors to reduce redundant data transmissions between TUs and the cloud. Finally, our experimental results demonstrate that the proposed EC-IoT over PLC network can significantly reduce energy consumption and transmission latency.

After more than two decades since intensive research began on power line communications (PLC) technology, this interesting field of telecommunication engineering is still progressing towards maturity. Despite some factors that delay its worldwide acceptance, its implementation is starting to take off. Research in PLC is motivated (i) by many factors such as the crowded radio frequency spectrum that requires to be sustained by alternative technologies and (ii) by the emanation of other new technologies that may help PLC to extend its practical implementation such as visible light communications or other wireless communication technologies like near‐field communications. PLC technology is used in applications requiring both low and high data rate but traditionally exploited in applications in which the node does not move. Nowadays, PLC has become widely accepted; hence, a review of the technology may be useful to keep the readers aware of new updates. In this paper, we provide an overview of the evolution of PLC technology over the last few decades.

There is a need to fulfill the growing capacity requirements of power line communication (PLC). One way to achieve higher data rates in PLC networks is to operate at higher frequencies and increase the used bandwidth. In the future, the increased PLC frequency range can overlap with several wireless communications systems resulting in interference for these transmissions and vice versa. Commonly used static notching results in inefficient spectrum utilization as in a given place and at a given time only a part of the frequency range may be occupied by other wireless systems. Some wireless signals like FM signals are very closely spaced. In practice it is impossible to utilize these narrowband unoccupied frequency bands. In this case we can cluster closely spaced signals. Guard bands around detected wireless signals must also be taken into account before defining usable frequency bands for PLC. In this paper, we use the 2-D LAD ACC algorithm to detect and cluster interfering signals. We also further develop the algorithm so that after clustering guard bands are added and reclustering, if necessary, is executed. The performance of this modified 2-D LAD ACC algorithm is analyzed using calculations and spectrum analyzer measurement results obtained from in-office PLC network in the frequency range 80–200 MHz. The results verify that the proposed method performs well by detecting and clustering continuous and non-continuous wireless signals and providing means for clever spectrum utilization in PLC-network.

Today, and especially in the future, there is an increasing need for complementary techniques to meet the growing capacity requirements of wireless communications. A high data rate connection with power line communication (PLC) is one attractive solution to achieve this need. One way to improve the data rates obtained in PLC networks is to increase the used bandwidth and operate at higher frequencies. At the same time, however, it should be kept in mind that the power lines, unfortunately, act as quite good antennas which can detect strong near-by FM and TV signals. In the future, the PLC frequency range can overlap with the broadcasting frequency bands resulting in interference for these transmissions and vice versa. With the static notching the whole FM-frequency band is notched during the PLC communication. This may result in inefficient spectrum utilization as in a given place and at a given time only a part of the FM-frequency band may be occupied. In this paper, a blind spectrum sensing algorithm based on forward consecutive mean excision (FCME) algorithm is proposed to locate the free frequency bands inside the broadcasting frequency range in PLC-network. The performance of this sensing algorithm is analyzed using spectrum analyzer measurement results and calculations in the broadcasting frequency range. The results verify that the proposed method performs well when detecting free frequency bands in broadcasting frequency band providing means for better spectrum utilization in PLC-network.

Exponential demand for broadband applications has elicited renewed interest in characterizing noise in power line communication (PLC) networks for optimal error performance analysis. PLC is economical and ubiquitous, however due to multipath phenomena and nonstationary impulsive noise, the PLC channel is very harsh to signal transmission. Recent studies reveal that PLC noise is cyclostationary and modelling its characteristic should exploit the spectral and temporal redundancy. In addition, preliminary research shows that PLC noise exhibits self-similarity and can be predicted by fractal theory. In modelling noise employing fractal theory, the Hausdorff dimension (D) needs to be approximated. D is related to Hurst parameter (H), which is a measure of self-similarity. Hence, it is important to estimate H for accurate noise prediction using fractal theory. H parameter estimators assume stationarity in time series data. Therefore, preprocessing is required for the case of PLC noise before estimating H to make it stationary as periodicity and nonstatioanrity affects the H estimators. In this study, we remove the periodicity hidden in the PLC noise obtained from measurement campaign within several university offices, workshops and laboratories. Then long-range dependence is estimated from this pre-processed noise data by employing three estimation algorithms: R/S (rescaled adjusted range) method, aggregated variance method and absolute values of aggregated series method. Results from the said estimation methods though not the same, show that the Hurst parameters obtained from various noise measurements are greater than 0.5, implying presence of self-similarity with long-term memory. Results from this study will find valuable applications in PLC noise modelling using fractal and chaos theory and in error performance analysis in both narrowband and broadband PLC systems.

Power line communication (PLC) over low-voltage grid, is an attractive technology for no-new-wiring networks. In such typical application fields as home networks and street lighting management system, PLC network is always vulnerable in robustness and the logical link is liable to be destroyed because of the different user's personalities and the special channel properties. To improve the robustness of PLC network, the reasons that lead to the failure of data link are revealed, and the main achievements of randomized initialization protocols for ad hoc networks are studied. According to the study results, a novel low cost intelligent control method in MAC protocol is proposed to automatically maintain the logical connectivity of the PLC network. The performance of the method is evaluated theoretically and experimentally.

Power line Communications (PLC) has gained a lot of interest for the last mile or access because the normal electric power line is utilized for transmission also communication signals. Considerable research effort has been extended on investigating the technologies about the physical (PHY) layer and the medium access control (MAC) layer. But the transmissions scheduling is still a key design problem, especially in multi-hop PLC networks. In this paper, a time slot reuse schedule (TSRS) is proposed, to scheduled access in the networks. It utilizes time slots assignment with special reuse for the nodes in the cell, to improve the channel efficiency. TSRS is an appealing concept for PLC networks, since there is always a manager controlling the network, and PLC networks are often master slave structure with tree topologies. For successfully preventing the potential collision between the nodes, the performance of networks is improved significantly, which is also corroborated by the simulation results.

The reliability and distance of Power Line Communication (PLC) are the most important factors, which limit the application of PLC in practice seriously. This paper discusses the specialties and the methods of building up the PLC networks, uses an improved Dynamic Ant Colony System algorithm (DACS) in dynamic routing of PLC networks, and the multi-path storage technology is given. The improved DACS enhanced the accuracy and efficiency of dynamic routing in two aspects, that is the best tours and the worst tours. A dynamic penalty on worst tours will open up chances for ants to navigate, limit intentions and provide cautions in an ant's decision to move. And ants can get better search guidance by concentrating only the best tours from all groups. The simulation and experimentation indicate that the improved DACS provides an effective dynamic routing method for the expansion of PLC. It is an effective method of improving the reliability of PLC.

Power line communication (PLC) technology has proved itself in the last decade as an interesting solution for data transmission and communication in domestic application. Lately, this technology has been considered as a potential solution for monitoring and diagnosis of a motor-fed inverter setup. Information issued from sensors would be sent via power cables back to the controller despite the harsh environment and the switching of the inverter. This paper discusses the use of PLC technology over a pulsewidth modulation network by underlining the effect of the power cable length and the inverter switching on communication. A new approach based on the measurement of scattering parameters is used for this purpose, and the effect of the cable length is analyzed. It is shown that, for long distances, the PLC technology may not be effective, and hence, it is not possible to use power cables for communication.

Power Line Communications (PLC) is regarded as the promising home networking technology for smart grid application since the PLC technology enables data transmission via the existing power line. The cooperation between PLC and Wireless Local Area Network (WLAN) will be an effective hybrid solution for Home Area Networks (HANs). In this paper, we consider that Transmission Control Protocol (TCP) packets are transmitting in heterogenous communications network based on PLC and WLAN. The existing TCP congestion control has low effectiveness due to the error-prone power line channel. Therefore, we propose an adaptive rate control to improve TCP performance in the hybrid PLC/WLAN HANs. We exploit the communications mechanism of WLAN to improve the PLC link utilization. The methodology of Heuristic Dynamic Programming (HDP) is employed to obtain the optimal rate policy. The bottleneck link capacity is estimated by neural network training. The sending rate is adapted according to the long-term quality of service (QoS) of applications. Simulation results illustrate that the proposed rate control effectively filters out the negative impact from the instantaneous impulse noise in PLC channel and outperforms the existing TCP.

As one of the most promising networking technologies, power-line communication (PLC) networks have been gradually used not only in home networking systems but also in industrial IoT (Internet of things). Current studies of PLC medium access control (MAC) protocol (i.e., IEEE 1901) only focus on the single-hop environment; however, in practical industrial IoT and home access communication systems, PLC networks generally utilize a multi-hop architecture. In addition, due to the difference in the MAC standard between 802 series and 1901, existing analytical models of multi-hop IEEE 802.11 wireless networks are not suitable for multi-hop IEEE 1901 PLC networks. In this paper, we propose a theoretical model for performance analysis of multi-hop IEEE 1901 PLC networks, where the impacts of traffic rate (containing relay traffic), buffer size, deferral counter process of 1901, hidden terminal problem and multi-hop environment are comprehensively considered. The modeling process is divided into two parts. In the local modeling part, we construct a brand-new Markov chain model to investigate the carrier sense multiple access with collision avoidance process of IEEE 1901 protocol under the multi-hop environment. In the coupling queueing modeling part, we employ queueing theory to analyze the packet transmission procedure between successive hops. On the basis, we derive the closed-form expressions of throughput, medium access delay, packet blocking probability, end-to-end successful transmission delay and goodput. Through extensive simulations, we verify that our theoretical model can accurately estimate the MAC performance of IEEE 1901 PLC networks in the multi-hop environment.

Power Line Communications have been the subject of an important research work. At the same time, the growing demand for multimedia communications provides a good prospect for PLC as a promising transmission technique for the “last mile” access network. Orthogonal Frequency Division Multiplexing (OFDM) is a spectrally efficient multicarrier modulation technique for high speed data transmission over multipath fading channels. High Peak-to-Average Power Ratio (PAPR) is a major drawback of OFDM. The high PAR of the OFDM signal has to be considered when setting the range of the digital-to-analog converter (DAC) and dimensioning the line-driver. This paper introduced an improved PAPR reduction scheme using constant envelope modulation. Furthermore, by utilizing continuous phase modulation (CPM) in a CE-OFDM system, the PAPR can be effectively reduced to 0 dB. The paper describes a CE-OFDM based modem for Power Line Communications (PLC) over the low voltage distribution network. Relying on a preliminary characterization of a PLC network, a complete description of the modem is given.

The paper presents a methodology proposal for testing and evaluation of communication systems in Smart Grids, especially for Power Line Communication (PLC) systems. The PLC technology is widely used in power grid as a part of Advanced Metering Infrastructure (AMI) allowing mainly data transfers between a management system at utility and customer-premises smart meters. However, the PLC technology on medium voltage (MV) lines is often used for remote control and monitoring of distribution transformers as well. Since power grid and consequently power lines have different transmission parameters affected by their placement and potentially burdened by interferences, the PLC systems have to be evaluated on site before placed to production. In this paper, authors propose a methodology for long-term benchmarking of the PLC systems using newly developed testing tools. The methodology is subsequently tested on real power grid and a selection of results is presented.