Studies On Training And Data Transmission Based Joint Decoding Methods

Mobile wireless communication system applications increasingly growing, this requires a morecomplex environment of wireless communication available to more users in more diverse serviceneeds of wireless communication technology, which means that the wireless communicationtechnology put forward higher standards. For wireless communication systems, knowing the exactchannel information (CSI, Channel State Information) is inportant for improving the performance ofthe system, but the vast majority of wireless communication systems, the channel information forthe receiver and sender are not sure. Therefore, in most cases, the sender will send sending thetraining sequence (Training Sequence) before the data string. When the receiver receives thetraining sequence, it will according to the training sequence do the channel estimation, the commonestimation method there ML estimation, LS estimation, MMSE estimation. Finally receiver usingthe obtained estimated channel state information on the back of the received data decoding.Channel estimation in a wireless communication plays an important role. This article brieflydescribes the history of the development of mobile communications, on this basis, carefullyintroducded the wireless channel model. Subsequently, the introduction of several common channelestimation methods, the focus was proposed based on training and data transfer joint decodingmethod. This paper deduced joint decoding method for channel estimation. The joint decodingchannel estimation method, also need to send the training sequence, but does not do the channelestimation. We use of joint decoding method, decode the received data directly. In this paper, jointdecoding method is derived, and made a theoretical analysis of its performance. We derived itsanalytical formulas of pairwise error probability, give the power allocation of training sequence andthe data, and show the coding rules preliminarily. Based on this formula analysis, it shows thatwithout joint decoding channel estimation method is superior to the performance of channelestimation method based on system performance. And in certain conditions, the system does notsend a training sequence outperforms training sequence based system performance.Theoretical studies show that in the fast changing channel environment, based on training anddata transmission joint decoding method has great application prospects. In case of rapidly changingchannels, the training sequence without joint decoding performance better than the performance ofthe training sequence used. This is because the rapid changes in channel conditions, the coherencetime of the channel decoding is very short, so that each training sequence transmitted only beapplied to the communication in a very short time, the utilization rate is not high, so the performance of decoding using the training sequence is not high. In real life, a lot of fast-changingchannel environment, such as high-speed rail, aircraft, space communications, in thesecircumstances, can not send a training sequence, the direct use of joint decoding method in order toget better performance.