Time and frequency prediction of the channel transfer functions in multiple antenna systems

A technique to predict the channel transfer functions into time direction and into frequency direction in multiple antenna systems is investigated in this paper. Having channel state information in a mobile radio system at both sides of the transmission link is crucial for many sophisticated transmission techniques. Typically, only receiver side channel state information can be achieved based on the transmission of a priori known training signals. Unfortunately, this estimated channel state information cannot be directly reused as transmitter side channel state information. In frequency division duplex systems different frequency bands are used, thus, the estimated receiver side channel state information differs significantly from the transmitter side channel state information. But also in time division duplex systems the estimated receiver side channel state information can often not be directly reused because of the delay between estimating the receiver side channel state information and using this information at the transmitter side. Thus, a prediction is required. In time division duplex systems only a prediction into time direction is relevant. In frequency division duplex systems a prediction into frequency direction and possibly also a prediction into time direction are relevant. This paper shows a technique to perform the prediction of the estimated receiver side channel state information to achieve transmitter side channel state information. Channel measurements were conducted in a typical indoor scenario in order to evaluate the performance of the proposed prediction techniques.