Design and Implementation of A Wideband Video Transmission System based on 2x2 MIMO-OFDM

Abstract

In this thesis, based on transmitter specification of DVB-T, multi-antenna 4x4 MIMO-OFDM transmitter was designed to replace traditional single-antenna system. Furthermore, new generation image-coding technique H.264 was also presented to be an alternate for MPEG-2. In order to simulate the non-ideal effects of wireless communication environment, base-band channel model including Multi-path Fading effect, AWGN effect, CFO effect was took into account. Under such an environment and according to its structure and non-ideal characteristics, the receiver including four major sections was designed: synchronization, channel response estimation and compensation, adaptive modulation and channel decoding. First, in the synchronization section, initial estimation, symbol boundary estimation and CFO estimation/compensation were contained.Second, in the channel estimation, scattered pilots was estimated in two-dimensional time and frequency domain, and then compensated by the MIMO detector. Thirdly, adaptive modulation mechanism was proposed, with modulation variable α、β corresponded with different channel condition. The adaptive modulation technique classified the image data into different level, and then transmits each level through its corresponding protection mechanism. In the last, a concatenate error-correction decoder was used, where Viterbi Decoder and Reed-Solomon Decoder were corrected by the error of channel effect. In the hardware part, with the aim of reducing cost and size, 4x4 MIMO-OFDM system was reduced to 2x2 MIMO-OFDM system; the transmitter, channel model and receiver were verified by two FPGA board.