Indoor Power Line Network Research Articles

Experimental and Theoretical Analysis of Throughput of MIMO PLC Network

In this study, we mainly focused on a theoretical analysis of HomePlug 1.0 and an experimental analysis of modem data rates through a section of a PLC network with several configurations. We introduce the utilization of the MIMO technique to increase the throughput over a PLC channel. Besides, we propose a MIMO PLC channel model to evaluate the channel transfer function of MIMO PLC. We used an equivalent per-unit-length model of the indoor power line network to characterize the three-conductor cable. Based on this mathematical model, we analyzed the throughput of the PLC network with different household appliances. The equivalent circuit of each appliance is also given. The simulation results showed that the throughput is influenced by household appliances connected to the sockets of a MIMO PLC network. Moreover, we also compared the throughput between single and multi-antenna systems. Based on the simulation results, we found that the data rate increased with frequency. In addition, the performance of the MIMO PLC system was almost 90% higher than that of a SISO PLC system in terms of channel capacity.

Characterisation of Signal Amplitude-Frequency for Indoor Power Line Communication Channel in the 1 — 30 MHz Broadband Frequencies

The transmission of data signals over power lines is a very promising technique for delivering indoor broadband communication services. However, since power grids were originally designed for high-voltage low-frequency signal transmission, there is a frequency mismatch between the power grid and high-frequency data signals. This mismatch poses a challenge to deploying power lines as a communication channel. Although, studies and researches conducted in several countries have made transmission of data over power lines possible, the behaviour and properties of the power grid cannot be generalised. Hence, the need for in-depth experiment and measurement on the suitability and capability of the Nigerian power grid for data transmission is crucial for proper characterising and modelling of the power line communication (PLC) channel. In this paper, we present experimental measurements and results of the effects of frequency variations on the attenuation experienced by broadband high-speed data signals transmitted over the Nigerian indoor power line network.

Investigation of the Lower Bound of Outage Threshold in Indoor Power-Line Networks

We theoretically investigate lower bound of the outage threshold based on channel capacity degradation in indoor power-line networks and its practical applicability to a realistic indoor power-line network existing in practice. We estimate the channel capacity degradations of arbitrary channels in networks with uniformly distributed branches with regular length. The channel capacity degradations are estimated under various network configurations, such as network size, branch characteristics (including the number and length), and loading conditions (including the number, type, impedance, and location). Based on the channel capacity degradation, the lower bounds of the outage threshold of arbitrary channels, which can evaluate the quality of the channels, are given. To evaluate the practical applicability of the simulated results, we compare the lower bounds of the outage threshold between a realistic network and simple networks. It is shown that the Pearson's correlation coefficients between the realistic network and the simple networks are predominantly greater than 0.85 ( $p$ -value ${ 0.01) in almost all cases, which shows a strong correlation in terms of the outage behavior. Therefore, our investigation enables estimating the outage behavior of a realistic network, without sufficient prior information of the network configuration using a simple network with a similar network configuration.

Design of Multicarrier Broadband Power Line Communication System for Tanzania Homes

Broadband Power Line Communication (BPLC) is a method of providing broadband internet access to consumers using High Frequency (HF) radio signals coupled into the mains power wiring. In the BPLC system, data signals are modulated at HF and injected into the power lines using broadband modulation techniques. Design of a BPLC system requires a complete understanding of the Power line network (PLN) topologies involved. PLN can be classified as Indoor or In-home, Low voltage, Medium voltage and High voltage respectively. In this study four maps representing typical Tanzania houses were selected randomly, and then four indoor power-line networks were derived from their circuit diagrams. The Impulse response was estimated at the switch sockets using the recent power-line channel model by Anatory et al. The delay spread estimated from the impulse response was used to design the OFDM system and the OFDM system performance was evaluated. General Terms Indoor Power Line Communications, Anatory et. al.

Modeling and Simulation of Temporal Variation of Channel and Noise in Indoor Power-Line Network

Broadband power-line communication (PLC) technologies are one of the main parameters of digital convergence voice-data-video in the home environment. These technologies use the power-line network as a propagation and a communication medium. Its transmission quality depends on the frequency behavior of the propagation medium and the connected household electrical appliances. The impedance of those devices and noise levels has a great impact on the PLC systems. In this paper, a simulator for indoor power-line channels is presented. In this paper, a new approach is presented for modeling temporal variations of noise and channel on indoor power lines. A three-conductor power cable (phase, neutral, and ground) is modeled by a circuit of four elements (resistor R, inductor L, capacitance C, conductance G). The RLCG parameters are deduced from the impedance measurement in open circuit and in short circuit. The cable model is validated in time and frequency domains. Then, the temporal variation of periodic noise is modeled by a stochastic approach. The global model, combining both channel and noise variations, is validated by comparing SPICE simulation and measurement results.

Time Domain Modeling of Powerline Impulsive Noise at Its Source

Noise characteristics of an indoor power line network strongly influence the link capability to achieve high data rates. The appliances shared with PLC modems in the same powerline network generate different types of noises, among them the impulsive noises are the main source of interference resulting in signal distortions and bit errors during data transmission. With regard to impulsive noise many models were proposed in the literature and shared the same impulsive noise definition: “unpredictable noises measured in the receiver side”. Authors are, consequently, confronted to model thousands of impulsive noises whose plurality would very likely come from the diversity of paths that the original impulsive noise took. In this paper, an innovative modelling approach is applied to impulsive noises which are studied here directly at their sources. Noise at receiver would be simply the noise model at source convolved by powerline channel block. In the new analytical model, the impulsive noise at source is described by a succession of short pulses, each modeled by a phase-shifted Gaussian. Noises at source are classified into 6 different classes [1], and a noise generator is established for each class.

Channel Characterization for Indoor Power-Line Networks

Power-line networks are promising mediums by which broadband services can be offered, such as Internet services, voice over Internet protocol, digital entertainment, etc. In this paper, an analysis of delay spread, coherence bandwidth, channel capacity, and averaged delay in the frequency bands up to 100 MHz for typical indoor power-line networks are studied. Earlier studies for indoor power-line networks considered frequencies up to 30 MHz only and earlier works have shown that at these frequency bands, the data rates are generally low and are inefficient for digital entertainment in comparison with wireless local-area networks standards, such as IEEE 802.11 n. In this paper, it is shown that at 100 MHz, the average channel capacity for typical indoor power-line networks can be up to 2 Gb/s and it is found that by increasing the number of branches in the link between transmitting and receiving ends, the average channel capacity decreases from 2 Gb/s to 1 Gb/s (when the number of branches was increased by four times for a power spectral density of -60 dBm/Hz). At the same time, the coherence bandwidth decreased from 209.45 kHz to 137.41 kHz, which is much better than the coherence bandwidths corresponding to 30-MHz systems. It is therefore recommended to operate the indoor power-line networks at 100-MHz bandwidths for a wide variety of broadband services.

Ultra wideband powerline communication (PLC) above 30 MHz

A novel study of ultra wideband (UWB) communication over the indoor powerline channel, in a wide frequency range up to 1 GHz is presented. An exhaustive measurement campaign was conducted on a test bed that replicated the environment of an indoor powerline network. The aim of this study was to observe and analyse the transmission and noise properties of such a broadband powerline channel. A time domain channel model has been used to study the broadband channel response of the powerline. Measurement and modelling results show that the indoor powerline channel provides a communication link in the 50–550 MHz frequency range. Channel capacity is greatly enhanced by exploiting the 500 MHz bandwidth. The conclusions of this study indicate that gigabit per second data rate transmission are possible over the indoor powerline channel in 50–550 MHz.

A low-complexity bandwidth allocation algorithm for frequency-selective multiuser OFDM systems

This paper addresses the problem of efficient bandwidth allocation for multiuser orthogonal frequency division multiplexing (OFDM) systems over frequency-selective channels. For a given coding and medium access scheme and for specific channel gains, the achievable data rates depend on the assignment of the available subchannels to the different users. However, in frequency-selective channels, the various users experience different channel conditions, thus the application of effective bandwidth allocation rules results in enhanced multiuser diversity. This paper presents a computationally efficient solution for dynamic subchannel assignment. The proposed algorithm provides enhanced system performance compared with the fixed time division multiple access (TDMA) solution and also results in proportional data rates according to channel quality of each user. As a case study, we demonstrate the performance of the proposed algorithm in the indoor power line network with multiple OFDM links between a central station and a number of user devices.

Long polyphase sequences for adaptive MMSE detector in asynchronous CDMA PLC system

An adaptive receiver solution for an asynchronous DS-CDMA system in an indoor powerline network is proposed. A combination of different receiver structures with binary and complex-polyphase sequences is evaluated and compared in terms of bit error rate. The simulation results based on a complete powerline channel model are reported.

Indoor Power-Line Communications Channel Characterization up to 100 MHz—Part II: Time-Frequency Analysis

Estimations of coherence bandwidth and time-delay parameters from wideband channel sounding measurements made in the 30 kHz-100 MHz band in several indoor environments are described in and taken back in this paper. Powerline communications (PLC) modems rather see a channel which starts almost from 2 MHz . A comparison between coherence bandwidth and time-delay parameters estimated in both frequency bands 30 kHz-100 MHz and 2 MHz-100 MHz is elaborated in this paper. Results are intended for applications in high-capacity indoor power-line networks. The investigation is aimed to show that the PLC channel studies in a band starting from a frequency lower than 2 MHz distorts the real values that an implementer should take, as the PLC modem see only the frequencies from 2 MHz. The coherence bandwidth and the time delay parameters are estimated from measurements of the complex transfer functions of the PLC channels. For the 30 kHz-100 MHz frequency band, the 90 th percentile of the estimated coherence bandwidth at 0.9 correlation level stay above 65.5 kHz and below 691.5 kHz. It was observed to have a minimum value of 32.5 kHz. The maximum excess delay spread results show that 80% of the channels exhibit values between 0.6 s and 6.45 s. And a mean rms delay spread of 0.413 s is obtained. The passage to the 2 MHz-100 MHz frequency band induced an increase of the coherence bandwidth, whose min value is brought back to 43.5 kHz, and an important reduction of the time delay parameters: The min, max, mean, and standard deviation values of the maximum excess delay are almost divided by 2. For the twice frequency bands, this paper studies, also, the variability of the coherence bandwidth and time-delay spread parameters with the channel class , and thus with the location of the receiver with respect to the transmitter, and finally relates the rms delay spread to the coherence bandwidth.

Fair Resource Allocation With Improved Diversity Performance for Indoor Power-Line Networks

The problem of fair resource allocation in power-line networks with multiple links is considered. A new bandwidth allocation criterion with improved multiuser diversity characteristics is presented, which provides an increased total data rate compared with other existing solutions. Simulation results demonstrate the effectiveness of the proposed method under different network loading conditions.

Performance Analysis of Uncoded and Coded OFDM Broadband Transmission Over Low Voltage Power-Line Channels With Impulsive Noise

Broadband communications for indoor power-line networks with impulsive noise using orthogonal frequency division multiplexing (OFDM) is considered. From earlier investigations, it is known that this channel suffers from multipath fading and frequency selectivity along with man-made impulsive bursty noise. Nevertheless, the calculated channel capacity limit promises very high data rates over this channel. Enhancement techniques, such as coding can help an OFDM system to tackle impulsive noise burst. In this paper, the bit error rate (BER) performance of the OFDM system under impulsive noise and frequency fading is theoretically analyzed and closed form expression for the performance is derived. Two different impulsive noise environment models are studied and it is confirmed that both models represent the same environment. Furthermore, a theoretical upper bound on the performance of coded OFDM system is obtained, given perfect interleaving. The effect of the interleaver length on coding performance is also studied. Simulations show that the upper bound is quite tight for the case of employing a longer interleaver. The effect of interleaver size on the system performance is studied, as well

Multipath Characterization of Indoor Power-Line Networks

The time- and frequency-varying behavior of an indoor power-line network is the result of variable impedance loads connected to its termination points. In fact, any signal transmitted through such a communications network is subject to time-varying multipath fading. In this paper, an analytical calculation method is presented, which can be used to determine the multipath components of any point-to-point channel in the indoor power-line environment. The method calculates all transmission characteristics of the network and, therefore, it can be exploited in the process of designing proper transmission algorithms for optimizing system performance. The proposed method is applied to an example network to demonstrate its usefulness in explaining the network's time-dependent behavior and in estimating channel parameters, such as subchannel bandwidth, multipath delay spread, fading conditions, etc.

Classification and characterization of impulsive noise on indoor power line used for data communications

The performance of a link using the indoor power line network as a medium for communication strongly depends on the noise characteristics. Besides the background noise and the narrow band noise mainly due to broadcast transmitters, impulsive noise adversely affects the quality of service. This paper focuses on impulsive noise measurements, their statistical properties being the basis of a noise model for optimizing a transmission scheme.