The Research Of Space-Time Coding Technic In Mobile Communication

The technique of space-time coding (STC) has been advancing drastically in recent years. This technique is mainly designed to combat channel fading in downlink transmission by combining the technique of channel coding and that of array diversity, hence increasing the capacity of wireless communications systems and giving diversity gain and coding gain to them. It can also improve the bandwidth efficiency of traditional single-antenna systems.In this thesis,wireless channel model and space-tune signal model are proposed firstly.Based on such model.we concretely discuss and analyse some typical space-time coding algorithms and bit error rate performance. Layered space-time code can be easily coded and decoded,it cann't achieve maximum transmit diversity and its performance is not very well.But it is the only coding method which make spectral efficiency increase linearly with unmbers of antenna, so it has a bright prospectln the thesis, we bulid a decoding algorithm without channel estimate based on sub-space algorithm. Space-time trellis coding can achieve maximum transmit diversity and coding gain.but it didn't be applied for its decoding complexity exponential increasing with number of antenna. In the paper ,we mainly analyse space-time block code which also achieve maximum transmit gain,but its performance is a little bit worse.The decoding of space-time block code also need exact knowledge of channel,but we cann't get knowledge of the channel for some complicated channel.In the paper,we also decode by sub-space algorithm.With numerical simulations and performance analysis, it is shown that the given algorithm's performanc near the algorithm which can get knowledge of the channel with the increasing of. successive code in receiving matrix.In the end a blind space-time coding without the knowledge of the channel is introduced,namely Unitary Space-time Code.