Channel Estimation Alogorithms And Implementation In MIMO Multiple Carriers Mobile Communication System

MIMO systems, having multiple antennas at transmit and/or receive ends, can increase channel capacity and provide very high spectral efficiency while using the same total power and band width as SISO systems. In ideal conditions, the capacity of the MIMO channel can be improved linearly with the number of transmit/receive antennas. Meanwhile, the appearance of multiple carriers communicate method makes the data transmit rate of each sub-carrier and reduces the ISI. The using of the multiple carriers makes system insensitive for time-delay dispersion of channel. Thus, system can also get good performance without equalizer. So the two technologies become key ones for high data rate, performance and capaticity in 3G mobile communication systems and beyond. And the research of channel estimation algorithms with high performance and low complexity is important in communication field.This article does the researches in the two systems.Firstly, it presents the algorithm simiulations of channel estimation in the MIMO-OFDM system. The channel estimators are usually classified into two types. One is decision feedback estimation; the other is pilot symbol assisted estimation. The latter is in common use while considering the complexity of the receivers and performance of the systems. According to some criteria such as minimizing certain error, least square and minimum mean square error estimators are mostly used. In practice, it's hard to design an estimator with low complexity and high channel track performance. In Chapter 4, beginning from the desigh of optimal pilots, the channel pulse response estimators in MIMO-OFDM systems are investigated on time-variety frequency selective fading channels.Secondly, it implements the channel estimation of single carrier block transmit system in the General Multi-Carrier Time Diversion Duplex x-Divison Multiple Access(GMC-TDD-xDMA) cellular mobile communication system. In this scheme, the guard interval of between time slots is composed of the cyclic prefixed pilot sequences. Based on this dual cyclic block transmit method, get the channel impulse response using the LS channel estimation algorithm and simple interpolation algorithm. Considerating the characteristics of the system structures and the complexity of hardware implementation, a hardware structure of channel estimation based on cyclic orthogonal pilot sequence and LS algorithms, featuring on pipeline architecture, is given. Then we implement this algorithm with few resources based on field programmable gate array(FPGA).