Research of dynamic routing based on improved Dynamic Ant Colony algorithm

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.

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.

Power Line Communication (PLC) channel is a very challenging environment, this is due to the fact that severe impairments adhering this medium. A more realistic and accurate noise model based symmetric alpha-stable distribution (SαS) is considered in this paper to better fit the properties of real noise inherent in power grid system. In this paper we study the impact of the degree of impulsiveness based SαS model on the performance of MIMO over PLC channel. Results show the improvement reached in PLC by using MIMO-OFDM, and reveal the effectiveness of considering a more realistic noise model.

Powerline communication (PLC) provides inexpensive, secure and high speed network connectivity, by leveraging the existing power distribution networks inside the buildings. While PLC technology has the potential to improve connectivity and is considered a key enabler for sensing, control, and automation applications in enterprises, it has been mainly deployed for improving connectivity in homes. Deploying PLCs in enterprises is more challenging since the power distribution network is more complex as compared to homes. Moreover, existing PLC technologies such as HomePlug AV have not been designed for and evaluated in enterprise deployments. To this end, we give guidlines for designing PLC networks for providing ubiquitous connectivity in enterprises, based on measurement study of PLC performance in enterprise settings using commodity HomePlug AV PLC devices. Based on our findings, we propose that careful planning of PLC network topology, routing and spectrum sharing can significantly boost performance of enterprise PLC networks.

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 impedance of power line channels is related to various factors such as frequency, time, connection location, load type, and power grid structure. The impedance mismatch will reduce the coupling efficiency and transmission efficiency of signals, and seriously affect the quality of power line communication. Therefore, accurate measurement of power line channel impedance and analysis of impedance characteristics are of great significance for improving the reliability of power line communication. In this paper, an improved ratio method considering the noise interference is proposed. In the method, the original generation method of sweep frequency signals is changed to one‐time multi frequency and variable amplitude injection signals. Based on real‐time signal processing technology, the voltage information at all tested frequency points is measured at once, including amplitude and phase. Through digital signal processing technology, the influence of noise is weakened, and the impedance amplitude and phase of all tested frequency points are accurately calculated. By the method, the requirements of the measurement circuit are simplified and the frequency range of impedance measurement is expanded to 100 kHz to 12 MHz. Finally, the impedance characteristics on the concentrator side and the user meter side are measured, laying the foundation for impedance matching design and improving power line communication quality.

Power-line communication (PLC) networks have been increasingly used for constructing industrial IoT (internet of things) and home networking systems due to their low-cost installation and broad coverage feature. To guarantee the transmission reliability, ARQ (automatic repeat request) scheme is introduced into the link layer of reliable PLC networks, which allows the retransmission of a data frame several times so that it has a higher probability to be correctly received. However, current studies of performance analysis for PLC MAC (medium access control) protocol (i.e., IEEE 1901) do not take into account of the impact of ARQ scheme. To resolve this problem, we propose an analytical model to investigate the MAC performance of IEEE 1901 protocol for reliable PLC networks with ARQ scheme. In the modeling process, we first establish a PLC channel model to reflect the impacts of PLC channel types (containing Rayleigh fading and Log-normal fading), additive non-Gaussian noise feature and ARQ scheme on data transmission at link layer. Next, we employ Renewal theory and Queueing dynamics to capture the transmission attempt behavior of executing IEEE 1901 protocol in the unsaturated environment with finite transit buffer size. On the basis of combining these two models, we derive the closed-form expressions of 1901 MAC metrics considering the influence of the ARQ scheme. Furthermore, we prove that the proposed analytical model has the convergence property. Finally, we evaluate the MAC performance of 1901 protocol for reliable PLC networks with ARQ scheme and verify the proposed analytical model.

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 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 evolution of technology has made the connection of all types of devices to IP networks possible. In this paper, the authors investigate the possible usage of IPv6 in sensor networks connected through the Power Line Communication (PLC) non-wireless medium and demonstrate possible interoperability. This work is based on the adaptation of the IEEE 802.15.4 standard protocol constrained by the low-power, lossy and low data-rate context of PLC transceiver that uses pulse modulation. The aim is to provide interoperability features with other media using a robust and reliable communication stack. The target application of such results ranges from smart metering and environment monitoring to home control and urban area energy efficiency applications. This paper proposes the first adaptation of the IEEE 802.15.4 standard commons for the PLC medium. Following this standard interface, the authors demonstrate data communication on PLC with low power energy requirement using the pulse PLC physical layer. This paper also presents an initial implementation of the Routing Protocol for Low power and lossy networks (RPL) setup proposed by the IETF working group. In this context, the authors demonstrate interoperability in a testbed between PLC and Wireless Sensor Networks (WSN).

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.

Communication is the transfer of information from one point to another over a channel. However, as technology is growing, more information is needed to be passed over large distances for the realization of the world being a global village. There is the need to place a reliable communication system that will transmit effortlessly both data and voice over a channel. Power Line Communication (PLC) also known as Broadband over Power Line (BPL) technology offers high speed and broadband communication services to homes connected to the power lines. This makes use of the electrical lines for transmission of data up to the last mile and there is no need of separating copper cables, short haul satellite systems, optical fibre cable and Wi-Fi. This work presented an overview of a voice and data communication over PLC in terms of the various types, equipment use, method of communication, application, regulatory activities on PLC and the challenges facing the implementation of power line for transmitting voice and data. Therefore, PLC is a viable alternative to all other methods of transmission as it is readily available and can be easily implemented in rural areas where other communication systems are not implemented for the transmission of voice and data communication. Keywords: Communication, Power Line Communication, Broadband over Power Line, Voice and Data Communication, Broadband over Power Line, Transmission, Electrical Line. DOI : 10.7176/MTM/9-8-03 Publication date : August 31st 2019

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.