Algorithm Research And FPGA Implenentation Of Channel Estimation And Equalization In CMMB System

With the continuous development of communications and information technology, mobile multimedia broadcasting is going to be an important implementation of radio and TV industry. For the past several years, a variety of mobile multimedia broadcasting standards has come into being all around the world. China Mobile Multimedia Broadcasting (CMMB) is published by the State Administration of Radio Movie and TV in 2006. CMMB is a stander with our own intellectual property, which has definitely a broad market prospects.As an important part of the chip designing project of CMMB receiving system, this paper mainly investigated the channel estimation and equalization module, including algorithm research, software platform of floating-point and fixed-point simulation, and FPGA implementation.CMMB is an OFDM system, which uses two-dimensional pilots to transmission training sequence. Pilot pattern of CMMB repeats every other OFDM symbol. And the frequency intervals of pilots in one OFDM symbol are not the same. So in this paper we made changes on several classical algorithm of channel estimation including Wiener filer based on MMSE, DFT interpolation and Nth-Order polynomial interpolation. And compare their performances. We choose the algorithm of estimation based on LS and interpolation of improved GAUSS finally for its good performance and low complexity.This paper also presents the development of the software platform using C++ to achieve the floating-point and fixed-point simulation, including its structure and the simulation flow.In the last part of this paper, we introduces hardware implementation of channel estimation and equalization on FPGA EP2S180F1020C3 of Altera's Stratix II series. The special algorithm we have chosen and characters of CMMB challenges its hardware design. This paper proposes some change on the structure of our system to reduce the complexity without any change on algorithm.