Modeling of OFDM Based Transceiver for Broadband Powerline Communication

In the recent past power line communication has emerged as an attractive choice for high speed data transfer and is looked upon as inexpensive and reliable media suitable for broadband internet access, home and office automation, in-vehicle data communication etc. In this paper we present an architecture for the physical layer of a PLC transceiver based on Orthogonal Frequency Division Multiplexing (OFDM) and the impact on multipath distortion for PLC transmission in terms of bit error rate. Since there is no standard PLC channel model available, a widely accepted multipath channel model is used for simulation purpose. Simulation results as well as FPGA synthesis verify the effectiveness of the proposed architecture for PLC modem design at 110 Mbps data rate.

A Power Line-delivered and Lamp-based Broadband Mobile Communication System

A new mobile communications network architecture is proposed to solve four existing bottlenecks that restrict the rapid development of mobile communications,as well as to meet the development demands of future broadband mobile communications. The architecture introduces the Information Lamp (IL),a novel device carrying out transceiver function,as the access point,besides providing light. It fulfills information interaction between the access points and radio access network through the power line (or fiber). The new system,supported by core technologies such as multi-antenna based distributed space-time signal processing and distributed radio resource management,integrates the wired and wireless networks to provide high-speed and high-quality mobile communication services.

Performance Evaluation for Medium Voltage MIMO-OFDM Power Line Communication System

Power line communication(PLC)provides intelligent electrical functions such as power quality measurement,fault surveys,and remote control of electrical network.Most of research works have been done in low voltage(LV)scenario due to the fast development of in-home PLC.The aim of this paper is to evaluate the link-level performance of a medium voltage(MV)MIMO-OFDM communication system based on transmission link under underground power line channel.The MIMO channel is modeled as a modified multipath model in the presence of impulsive noise and background noise.We first perform a measurement on the practical MV MIMO channel parameters for a section of buried cable of 1 km long in Ganzhou city,Jiangxi province,China.Based on the measured channel,we design the frame structure based on an IEEE standard for broadband over power line networks[1]to support MV MIMO-OFDM transmission.According to designed frame structure,we design an encoder and a decoder for a dual binary tail-biting turbo code and optimize some key decoder parameters for low bit error rate performance.Finally,the link-level performance for both spatial multiplexing and spatial diversity are evaluated.Numeral results show that MV MIMO-OFDM is a promising approach to provide both high data rate and link reliability for PLC.

Polar codes based OFDM-PLC systems in the presence of impulsive noise

Power line communication(PLC)has the potential to become the preferred technique for providing broadband communication to homes and offices with advantage of eliminating the need for new wiring infrastructure and reducing the cost.But it suffers from the impulsive noise because it introduces significant time variance into the power line channel.In this paper,a polar codes based orthogonal frequency division multiplexing(OFDM)PLC system is proposed to deal with the impulsive noise and thereby improve the transmission performance.Firstly,the impulsive noise is modelled with a multi-damped sine function by analyzing the time behavior of impulse events.Then the polar codes are used to combat the impulsive noise of PLC channel,and a low complexity bit-flipping decoding method based on CRC-aided successive cancellation list(CA-SCL)decoding algorithm is proposed.Simulations evaluate the proposed decoding algorithm and the results validate the suggested polar codes based OFDM-PLC scheme which can improve the BER performance of PLC with impulsive interference.

Cross-layer Resource Allocation on Broadband Power Line Based on Novel QoS-priority Scheduling Function in MAC Layer

Traditional resource allocation algorithms use the hierarchical system, which does not apply to the bad channel environment in broadband power line communication system. Introducing the idea of cross-layer can improve the utilization of resources and ensure the QoS of services. This paper proposes a cross-layer resource allocation on broadband power line based on QoS priority scheduling function on MAC layer. Firstly, the algorithm considers both of real-time users’ requirements for delay and non-real-time users’ requirements for queue length. And then user priority function is proposed. Then each user’s scheduled packets number is calculated according to its priority function. The scheduling sequences are based on the utility function. In physical layer, according to the scheduled packets, the algorithm allocates physical resources for packets. The simulation results show that the proposed algorithm give consideration to both latency and throughput of the system with improving users’ QoS.

WAVELET-BASED OFDM-CDMA HIGH SPEED POWER LINE COMMUNICATION SYSTEMS

This letter derives the Equivalent M-band Discrete Wavelet(EMDW) transmission mode of Orthogonal Frequency Division Multiplexing(OFDM) transmission systems, and presents a new Quadrature M-band Discrete Wavelet(QMDW) based OFDM-CDMA(Code Division Multiple Access) communication systems for high speed Power Line Communication (PLC) channels.This system gives much better robustness to Inter-Channel Interference (ICI), Multi-User Interference (MUI) and noise interference, which is verified by simulation.

Traffic Modeling of a Finite-Source Power Line Communication Network

Power line communication (PLC) is a promising smart grid application for information transmission using existing power lines. We analytically model a finite-source PLC network subject to channel failure through a queueing theoretic framework. The proposed PLC network model consists of a base station (BS), which is located at a transformer station and connected to the backbone communication networks, and a number of subscriber stations that are interconnected with each other and with the BS via the power line transmission medium. An orthogonal frequency division multiplexing based technique is assumed for forming the transmission channels in a frequency spectrum. The channels are subject to failure during service due to noise. We determine the steady-state solution of the proposed model and derive a set of performance metrics of interest. Numerical and simulation results are presented to provide further insights into the analytical results. The proposed modeling method is expected to be used for evaluation and design of future PLC networks.

Smart Home Networking: Lessons from Combining Wireless and Powerline Networking

Integrating the power grid technology with renewable power generation technologies, Demand Response (DR) programs enabled by the Advanced Metering Infrastructure (AMI) were introduced into the power grid in the interest of both utilities and residents. They help to achieve load balance and increase the grid reliability by encouraging residents to reduce their power usage during peak load periods in return for incentives. To automate this process, appliances, in-house sensors, and the AMI controller need to be networked together. In this paper, we compare mainstream network technologies applicable to home appliance control and propose a solution combining Power Line Communication (PLC) with wireless communication in smart homes for the purpose of energy saving. We extended NS-2, a popular network simulator, to model such combined network scenarios. Using a number of different routing strategies, we then model and evaluate the network performance of DR programs in smart homes in such a combined network.

Broadband hybrid model for relay-aided cooperative MIMO power line communication systems

A hybrid model for broadband multiple-input multiple-output(MIMO) relay-aided indoor power line communications(PLC) system was proposed in this paper. The proposed model combines the top-down and bottom-up approaches and extends to a two-hop relay-aided cooperative system with variable gain relay in amplify-and-forward(AF) mode. Based on the proposed PLC model and generated channel, the channel statistical characteristics are further investigated in 2 MHz^100 MHz bandwidth. Simulated results show that the proposed model overcomes the difficulties that the existing models need a lot of topological information of the network or measurements information. It provides a practical simulation analysis method for cooperative relay MIMO-PLC system. The results also show that cooperative MIMO relaying communications can improve the indoor PLC performances and communication reliability.

Analysis of electromagnetic field emitted from home plug power line used for indoor high-speed broadband communication

High-speed broadband power line communication(BPL)is a novel and practicable technique for NetatHome or home area local area networking(LAN).Because of the characteristics of BPL,the electromagnetic wave emitted from the BPL transmission media will influence the indoor electromagnetic environment,which would also affect the performance of other wireless communications.Based on the analysis of the communication channel characteristic,network impedance and attenuation characteristic of the BPL,this paper proposes a novel model for calculating the BPL radiation and the computer simulation model,which are proved by the coherence of the simulation and the test data.The interferences from the high-speed BPL to indoor wireless communications are analyzed to stipulate the standards of high-speed BPL in the future.

A Novel Device for Real-Time Monitoring of High Frequency Phenomena in CENELEC PLC Band

This paper proposes the design and development of a novel, portable and low-cost intelligent electronic device (IED) for real-time monitoring of high frequency phenomena in CENELEC PLC band. A high speed floating-point digital signal processor (DSP) along with 4 MSPS analog-to-digital converter (ADC) is used to develop the intelligent electronic device. An optimized algorithm to process the analog signal in real-time and to extract the meaningful result using signal processing techniques has been implemented on the device. A laboratory environment has setup with all the necessary equipment including the development of the load model to evaluate the performance of the IED. Smart meter and concentrator is also connected to the low voltage (LV) network to monitor the PLC communication using the IED. The device has been tested in the laboratory and it has produced very promising results for time domain as well as frequency domain analysis. Those results imply that the IED is fully capable of monitoring high frequency disturbances in CENELEC PLC band.

A reliable opportunistic routing for smart grid with in-home power line communication networks

The topology of in-home power line communication(PLC) networks varies frequently, which makes traditional routing algorithms failure. To solve this problem, an end-to-end transmission time for remaining path(TTRP) metric-based opportunistic routing(TTRPOR) is proposed. Since a local broadcasting scheme is adopted, the algorithm can find the optimal path for forwarding packets in a dynamic PLC network. The closed-form of the outage probability for a PLC channel is derived to estimate the TTRP. It is proved that the average throughput can achieve maximum as the metric TTRP is utilized to sort candidate forwarding nodes.Numerical results show that the end-to-end throughput of networks with TTRPOR, outperforms that of the network adopting DSR and EXOR, especially for the case of varying-topology in-home PLC networks.

Particle filtering based channel estimation in OFDM power line communication

Particle filtering （PF） algorithm has the powerful potential for coping with difficult non-linear and non-Gaussian problems. Aiming at non-linear, non-Gaussian and time-varying characteristics of power line channel, a time-varying channel estimation scheme combined PF algorithm with decision feedback method is proposed. In the proposed scheme, firstly the indoor power line channel is measured using the pseudo-noise （PN） correlation method, and a first-order dynamic autoregressive （AR） model is set up to describe the measured channel, then, the channel states are estimated dynamically from the received signals by exploiting the proposed scheme. Meanwhile, due to the complex noise distribution of power line channel, the performance of channel estimation based on the proposed scheme under the Middleton class A impulsive noise environment is analyzed. Comparisons are made with the channel estimation scheme respectively based on least square （LS）, Kalman filtering （KF） and the proposed algorithm. Simulation indicates that PF algorithm dealing with this power line channel estimation difficult non-linear and non-Gaussian problems performance is superior to those of LS and KF respectively, so the proposed scheme achieves higher estimation accuracy. Therefore, it is confirmed that PF algorithm has its own unique advantage for power line channel estimation.

In-home Power Line Communication Media Access Control Protocol Based on Collision Resolution

Most existing media access control(MAC) protocols in power line communication(PLC) networks just discard the colliding data packets when collision occurs.The collision deteriorates throughput and delay performance of system under high traffic conditions.This article presents a novel media access scheme with fast collision resolution for in-home power line networks.It works by first recognizing the colliding stations through detecting the inserted unique ID sequence ahead of data packets,then the source nodes retransmitting their packets immediately after the collision slot.The proposed protocol maintains the benefits of ALOHA systems.It needs no scheduling overhead and is suitable for bursty sources,such as multimedia data packets.Computer simulations have demonstrated that this approach can achieve high throughput due to its ability of resolving collisions.

基于图论的宽带电力线MIMO信道特性研究

多输入多输出(multiple-input multiple-output,MIMO)技术已被应用到宽带电力线通信(power line communication,PLC)中,精确建立MIMO信道模型对宽带MIMO电力线传输技术的研究和系统设计具有重要意义。已有的自底向上和自顶向下的MIMO PLC信道模型在实际应用中都受到限制,该文主要针对三导体电力线网络,首次提出了基于图论的2×2MIMOPLC信道建模方法。该方法首先需要明确电力线网络拓扑结构和分布式参数,通过迭代列举算法(iterative enumeration algorithm,IEA)的递归运算求解前K条最短路径得出给定拓扑结构的电力线网络的信道传输函数,克服了电力线网络结构复杂时自底向上模型的局限性,同时避免了自顶向下模型对信道的数据测量。利用三导体传输线理论和测量结果验证了所提出方法的有效性,并与传输线理论方法进行比较,证明了该方法简单实用,对宽带电力线MIMO信道研究和工程应用有重要意义。

OFDM编码在宽带电力线通信中的应用及其改进

基于正交频分复用(OFDM)的概念,给出了在宽带电力线通信(PLC)中应用OFDM编码方法及其实现模型,并分析了常用编码OFDM技术应用于宽带电力线通信中存在的优点及不足。针对无效频谱现象,提出使用前置编码OFDM来改进常用编码OFDM技术的方案,并在模拟的低压电力载波通道模型上对这两种技术进行了宽带PLC模拟仿真,结果表明应用前置编码OFDM技术可以大幅度减小传输信号误码率,并且简化了常用编码OFDM通信系统实现的复杂性。

宽带电力线载波信道编码与分集技术分析

电力线载波通信信道是一种传输环境恶劣的传输介质,不但有阻抗匹配和频率选择性衰落问题,还存在着严重的噪声和窄带干扰,并且其信道特性会随用电高峰时间分布而改变。信道编码和时频分集是2种有效的克服电力线载波信道时变性的技术。然而信道编码和时频分集这2种技术的各自特点及二者适合克服的具体电力线信道难题业界还未有定论。文章采用多种电力线信道模型,在不同模型下,对不同编码速率R的Turbo码和时频分集重数N的ROBO分集,做R与N之间的排列组合仿真,得出信道编码速率R与时频分集重数N在不同信道下的适用场景。

电力线通信系统的电磁兼容性研究

电磁兼容性(Electromagnetic Compatibility,EMC)是电力线通信(Power Line Communication,PLC)系统的关键技术之一。首先介绍了PLC技术的发展概况和相应EMC研究的基本情况;并介绍了有代表性的国家或地区和重要的标准化组织在PLC技术的EMC法律法规和标准方面的最新进展;然后介绍了我国在该领域的试验结果和研究成果;最后指出该领域存在的问题、同时对发展方向提出建议。上述研究总结了PLC技术的EMC法规和标准化的最新进展,可作为我国发展PLC时制定合理的EMC法规和管理制度的有益参考。

HomePlug第一届电力线通信技术会议综述

HomePlug第一届电力线通信技术会议于2005年9月27至28日在美国旧金山召开,文章首先介绍了HomePlug电力线联盟及其成员会议情况,然后从HomePlug电力线通信技术的发展、标准化、芯片设计、产品开发、市场需求和商业化运营等方面,对HomePlug第一届电力线通信技术会议进行了综述,最后结合我国情况对会议的几点体会做了简要介绍。

宽带电力线通信技术在电视上的应用研究

研究了电力线通信技术,特别是应用于家庭内宽带联网的基于低压电力线的宽带电力线通信技术。基于G.hn宽带电力线通信技术,提出了一种智能网络电视系统设计方案,实现智能网络电视通过电力线连接有线网络,并研究了G.hn的耦合隔离和滤波电路、控制通信协议、组网配置和加密配对。该系统经过测试和整改优化,网络吞吐量符合设计目标。