Conquering the harsh PLC channel to enable QOS guaranteed multimedia home networks.

摘要

Powerline Communication (PLC) is one of the most promising candidates for use in home network technologies. Although the powerline was originally designed for electrical power transmission at 50 or 60 Hz, it is also possible to transmit broadband signals at higher frequencies. One of the most attractive features of PLC is its whole house accessibility because a large number of powerline outlets are available in typical homes and offices. This dissertation is mostly focused on multimedia communication and home networks on PLC channel. First, we investigate generally available home networking standards and technologies such as HomePNA, MoCA, HomePlug AV, IEEE 802.11, G.hn, and IEEE P1905. Then, their advantages and disadvantages are compared in terms of data rate, QoS, accessibility, costs, and security. In order to guarantee QoS for PLC multimedia networks, a modified CSMA/CA MAC algorithm is proposed. The proposed MAC algorithm is based on the IEEE 802.11e and the HomePlug 1.0 MAC protocol. Despite the advantageous of PLC there are several hurdles to achieving reliable high speed communications over the Garth PLC channel conditions. For example, one of the typical features of the powerline channel is impulsive noise which degrades the PLC performance. Therefore, we first propose an impulsive noise mitigation scheme with a threshold setting algorithm. Then, LDPC codes with adaptive multi-carrier OFDM are applied to improve the bit error rate of our system on powerline channels. The comparison between LDPC codes and turbo codes is simulated with different block sizes. Finally, QC-LDPC codes are designed for better error correcting efficiency with less memory storage. The main advantages of the encoding procedure for QC-LDPC codes are their ease of implementation and relatively simple structure. QC-LDPC codes using various block sizes and code rates are compared. We also compare turbo codes with QC-LDPC codes with G.hn standard on real PLC channels. When SNR is 2 dB or more, error rates of (8640,4320) QC-LDPC code are 10 percentage or less of error rates of turbo code.