Bahram Honary

Power line communications: state of the art and future trends

This article constitutes an overview of the research, application, and regulatory activities on power line communications. Transmission issues on the power line are investigated and modeling approaches illustrated. Contemporary communication techniques and reliability issues are treated. A description of regulatory activities worldwide is given. Finally, market perspectives and promising applications are covered to assess the viability of this communications environment.

Construction of low-density parity-check codes based on balanced incomplete block designs

This correspondence presents a method for constructing structured regular low-density parity-check (LDPC) codes based on a special type of combinatoric designs, known as balance incomplete block designs. Codes constructed by this method have girths at least 6 and they perform well with iterative decoding. Furthermore, several classes of these codes are quasi-cyclic and hence their encoding can be implemented with simple feedback shift registers.

Fast Chase algorithm with an application in turbo decoding

Turbo product codes (TPCs) provide an attractive alternative to recursive systematic convolutional (RSC)-based turbo systems. Rather than employ trellis-based decoders, an algebraic decoder may be repeatedly employed in a low-complexity, soft-input/soft-output errors-and-erasures decoder such as the Chase algorithm. Taking motivation from efficient forced erasure decoders, this implementation re-orders the Chase algorithms repeated decodings such that the inherent computational redundancy is greatly reduced without degrading performance. The result is a highly efficient fast Chase implementation. The algorithm presented here is principally applicable to single error-correcting codes although consideration is also given to the more general case. The new decoders value in practical turbo schemes is demonstrated via application to decoding of the (64,57,4) extended Hamming TPC.

Trellis decoding for block codes

Disclosed is a novel bigraft copolymer comprising a polyhydrocarbon backbone selected from the class consisting of aromatic homopolymers, saturated and unsaturated hydrocarbon homopolymers, such homopolymers having halogen functionality and copolymers and terpolymers formed therefrom, and two different branches which are selected from the group consisting of monovinyl aromatic compounds and isoolefins. The bigraft copolymer is formed by the selective sequential cationic initiation of a first charge of one monomer onto the backbone at specific functional positions thereon and in the presence of a suitable solvent and an alkylaluminum compound. The resultant monograft copolymer is subsequently subjected to a second charge of another monomer, in the presence of a suitable solvent and an alkylaluminum compound, which becomes polymerized at the remaining, different functional positions available on the backbone. Also described are steps for substituting desired functional groups on the backbone and for the separation and purification of the mono and bigraft copolymer products.

New constructions of quasi-cyclic LDPC codes based on special classes of BIBD's for the AWGN and binary erasure channels

This paper presents new methods for constructing efficiently encodable quasi-cyclic LDPC codes based on special balanced incomplete block designs (BIBDs). Codes constructed perform well over both the AWGN and binary erasure channels with iterative decoding.

Space-frequency coded OFDM system for multi-wire power line communications

In this paper, we propose an efficient space-frequency coded orthogonal frequency-division multiplexing (OFDM) system for high-speed data transmission over frequency selective multi-wire power line channels. By transmitting the same data symbol over two uncoupled pair of wires and over two different carriers, with a frequency separation between carriers greater than the coherence bandwidth of the channel, the proposed scheme extracts both space and frequency diversity in the absence of channel knowledge at the transmitter. Numerical results are provided to demonstrate the significant performance improvement obtained by the proposed scheme over conventional single-wire OFDM systems when the frequency selective power line channel is corrupted by impulsive noise.

High-speed narrowband PLC in Smart Grid landscape — State-of-the-art

The prospect of Smart Grid (SG) is becoming a reality in the recent years, covering different areas like smart metering, demand side management, or distributed generation. Communications play a central role in the SG architecture, because the power utilities need to collect important information to make optimal decisions for efficient power generation, transmission and distribution. This paper discusses the state-of-the-art of narrow-band high-speed power line communications (PLC) - a promising communication platform for SG which offers advantages in coverage, costs and availability. Further, the paper presents an overview of DLC+VIT4IP (Distribution Line Carrier: Verification, Integration and Test of PLC Technologies and IP Communication for Utilities) a EU funded project under the 7th Framework Programme (FP7) that aims to extend the existing PLC technologies by developing efficient transport of IPv6 protocol, automatic measurement, configuration and management, and security. In addition, the project is exploiting frequency ranges up to 500 kHz, to support systems serving larger smart grid applications.

Trellis decoding of block codes: practical approach

We present a number of techniques which promise to make the soft-decision trellis decoding of block codes as powerful and cost effective as that of convolutional codes. The techniques are based on the concept of generalised array codes (GACs) and enable sufficient simplification in the decoding complexity.

Twenty years of ultrawideband: Opportunities and challenges

It has been 20 years since the word ultrawideband (UWB) has first been used in the open literature. In these 20 years, ideas have been transformed into real products. Yet, some might object that UWB has not yet lived upto the promises of gigabit wireless. This review shows that despite some drawbacks, UWB is not only needed because of the spectrum gridlock but it can still deliver its promises, including gigabit wireless. To do so, the gap between the potential, which is achievable, and the current performance must be closed. Thus, this review identifies some main issues of UWB (range, bit error rate performance, data rate, chip complexity and issues associated by strong narrowband interference). It shows that their reasons are well understood and addressed by erudite research, which includes low complexity chip design, alternative modulation schemes, multiple antenna systems, UWB radio-over-fibre, higher band UWB and interferer detection and suppression techniques. A specific feature of this review is the cross-layer approach. The latest findings from different system layers, for example, wave propagation, are linked to the system performance or complexity.

IP-centric high rate narrowband PLC for smart grid applications

The Internet Protocol version 6 is expected to be a strong enabler for the smart grid, promising seamless communication and network technology independence. However, IP has to be delivered to the last node in the field in order to become the lingua franca of the future smart grid. This article presents a novel approach in power line communication that delivers high resilient communication capable of efficiently transmitting IPv6. Based on the requirements of smart grid applications, the architecture of the communication system developed in the DLC+VIT4IP project is presented. New techniques for integrating IPv6, IPsec security, robust header compression, and end-to-end QoS are described, demonstrating the capability of PLC to efficiently handle IPv6 in the field level of the smart grid.