tailieunhanh - Báo cáo hóa học: " Research Article Improving a Power Line Communications Standard with LDPC Codes"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Improving a Power Line Communications Standard with LDPC Codes | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 60839 9 pages doi 2007 60839 Research Article Improving a Power Line Communications Standard with LDPC Codes Christine Hsu 1 Neng Wang 1 2 Wai-Yip Chan 1 and Praveen Jain1 1 Department of Electrical and Computer Engineering Queen s University Kingston ON Canada K7L 3N6 2 Nortel Networks Richardson TX 75082-4399 USA Received 31 October 2006 Revised 7 March 2007 Accepted 4 May 2007 Recommended by Lutz Lampe We investigate a power line communications PLC scheme that could be used to enhance the HomePlug standard specifically its ROBO mode which provides modest throughput for the worst case PLC channel. The scheme is based on using a low-density parity-check LDPC code in lieu of the concatenated Reed-Solomon and convolutional codes in ROBO mode. The PLC channel is modeled with multipath fading and Middleton s class A noise. Clipping is introduced to mitigate the effect of impulsive noise. A simple and effective method is devised to estimate the variance of the clipped noise for LDPC decoding. Simulation results show that the proposed scheme outperforms the HomePlug ROBO mode and has lower computational complexity. The proposed scheme also dispenses with the repetition of information bits in ROBO mode to gain time diversity resulting in 4-fold increase in physical layer throughput. Copyright 2007 Christine Hsu et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Power line communications PLC have received increasing attention due to the wide availability of power lines even though PLC face the challenge of harsh and noisy transmission channels. HomePlug is a current industry standard for PLC in North America 1 . It uses concatenated Reed-Solomon RS and convolutional .