Wireless Downlink Schemes With Partial Channel State Information

The wireless communication has got great achievement over the last decades, In order to maintain these growth rates, next generation wireless systems must supply both reliability and high data rates with a fixed amount of spectrum and limited power. Multiple-Input-Multiple-Output(MIMO) wireless communication systems which use multiple antennas at both transmitters and receives are widely accepted to be one of the key technologies for next generation wireless systems, because it can provide both high data rates and reliability improvement by designing signal over space as well as time and/or frequency.One of the key features of wireless link is the phenomenon known as fading. MIMO systems can provide high diversity gain to effectively decrease fading. Many MIMO designs are based on the basic assumption that the channel state information is unknown to the transmitter. However, if the signal can be adapted to the current channel state conditions, the performance can be improved undoubtly. Unfortunately many wireless systems will not have any form of priori channel knowledge without feedback from the receiver to the transmitter. As feedback will occupy spectrum sources, so it must be kept in a limited number of bits. On the other hand, the wireless channel is time varying and fading, so the feedback channel state information is outdated but exist some coherence to the current downlink channel state information. In one word, owning to the limited feedback bits or delay feedback the channel state information will be called as partial channel state information.Our focuse is mainly based on the signal designing when partial channel state information is known to the transmitters. Firstly the joint linear optimization for the transmitters and receivers when there exist some error duing to feedback delay and Doppleir shift is being discussed. Also precoding technology both in narrow band and wide band communication systems is been studied. Our result indicates that the system's performance can be great enhanced by utilizing partial channel state information.The new ideas, important results and benefits in this thesis are as follows:...