Adaptive channel characterization for wireless communication

Sensing the communication channel is an essential task in wireless communication systems. This is necessary for retrieving the sent information from the received signal. In stationary (time-invariant) channels, this task is accomplished once by transmitting a series of training symbols at the beginning of a transmission phase. In time-varying channels, so called pilot symbols are transmitted regularly. This decreases the effective channel capacity. The capacity loss is the ratio between pilot and information symbols sent in a certain time frame. It increases as the channel time variation becomes faster. In this paper, an adaptive technique is introduced, which is based on tracking the time variation of the channel in order to adapt the number and distribution of the pilot symbols aiming at maximizing the capacity.