A new approach to tracking time-variant channels

This paper presents a method for joint channel and data estimation for transmission over frequency-selective and time-variant channels. Hereby, fast time-variant channels can be tracked, which is important for mobile communications at high velocities. We approach the problem by estimating the scattering function, which depends on delay and Doppler frequency. At the transmitter, a short training sequence is inserted at the beginning of the data block. This sequence is used for initializing a recursive estimation filter, which carries out the joint channel and data estimation adaptively. After the training sequence hypothetical data symbols are considered to extend the persecuted paths in the data tree.