Space-time Code In The Ultra-wideband Communication Systems

Ultra-wide band (UWB) communication is a novel short-distance wireless communication technique. It has a lot of advantages, such as high transmission rate, low power consumption, robustness to multi-path and so on.Also it has wide applied foreground in many fields such as Wireless communication,radar,track,precise orientation,imaging,weapon control etc.MB-OFDM-UWB scheme is first proposed by Intel and Ti companies. The scheme divides the whole frequency band into many small bands.the advantage of this scheme is that deal with information in smaller band ,not only debase the complexity of design,consumption and cost,but also increase the utilization rate of Spectrum.Multiple-Input Multiple-Output(MIMO)system is well known for its potential of improving system performance under multipath scenarios.In particular, a large number of propagation paths between transmit and receive antennas can be utilized to combat channel fading effect and gain link reliability. By the use of Space-Time(ST)coding techniques, MIMO can provide both diversity and coding advantages simultaneously, and hence yield high spectral efficiency and remarkable quality improvement.First, in this dissertation,using OFDM to realize 528MHz bandwidths based on the MB-OFDM system model, then simulate it using matlab.the result indicate that frequency spectrum of each sub-band meets the requirements of MB-OFDM scheme,different frequency band can parallel transmit.After discussing and simulating four UWB typical channel,the STBC-MB-OFDM-UWB system and the STTC-MB-OFDM-UWB are mainly analysed,on the condition of channel CM1-CM4,STBC-MB-OFDM and MB-OFDM,STTC-MB-OFDM and H 84code are compared.the result show that CC-STBC-MB-OFDM,STTC-MB-OFDM have better performance.Above research preliminary show that apply space-time code into uwb can decrease system error rate ,improve communication system performance,realize the date high speed tranmission.In the end of this paper, we sum up our main studies, and take an outlook for further research.