Research On High Performance Channel Coding And High Efficient Transmission Technique In Wideband Communication Systems

Many specifications of bandwidth communication systems have been gradually proposed and revoluted, because of the progress of semiconductor techniques, the developed communication technology, and the communication bearing services changed from traditional voice and text to high bit-rate photos and multimedia data. For the bandwidth communication, in the point of designing, physical layer is the key of increasing the capacity of communication systems; in the point of application, transmitted power and the efficiency of frequency are the bottleneck. These conditions could be solved by changing the type of channel coding and modulating. Turbo codes and LDPC codes are error-correcting codes which approchs to Shannon's capacity limit. These two codes can maximize the coding gain in the same error bit rate, thus minimize the transmitted power. OFDM multi-carriers transmission technique not only decreases or cancels the Inter-Symbol Interference and frequency selective fading both caused by the physical channel, but also by orthogonalizing the transmission channel maximizes the efficiency of frequency. These two are employed in many recent specifications of bandwidth communication systems.Homeplug AV and 802.11n are the bandwidth access standards in digital home local area network.Homeplug AV is used to transmit the audio and video through the powerline. Proposed by IEEE(Institute of Electric and Electronic Engineering), the standard wireless local area network(WLAN) 802.11n will be the final edition for the maximum transmission rate and maximum transmission distance.This paper employs the draft edition of 802.11n.The main work lists below: setting the simulation platform of powerline channel in Homeplug AV; descripting the principle of OFDM and the parameter of OFDM in Homeplug AV and 802.11n in detail and the channel estimation algorithm of OFDM and in Homeplug AV; presenting the encoding process of turbo product code, LDPC code, binary convolutional code (BCC) and Turbo convolutional code (TCC); doing the decoding algorithm of BCC and TCC. The innovative point of this work is adding a progress of iterative estimation of circular state based on the traditional binary TCC optimal decoding algorithm obtaining good performance, then giving many simulation results in different modulation types.The work above has got a startling achievement. The algorithms have tested by simulation and its performance is better than other algorithms, and have employed in ASIC chip design of Homeplug AV.