A method and system are directed to enabling a detector to perform
relatively accurate channel estimates on blocks of data that include
relatively short training sequences in wireless communication signals.
Channel re-estimation is performed by transferring the estimation
calculations from the time domain into a channel state domain. In one
embodiment, information obtained from known training sequences and
unknown data may be combined to generate an initial channel estimate. An
embodiment of a new recursive Expectation Maximization (EM) process
generally i) initializes the EM process with the initial channel
estimate; ii) determines updates for the channel estimates; iii) produces
a reduced observation vector; iv) generates a special sequence of channel
states; v) rearranges each channel state estimate in the reduced
observation vector; vi) generates a low-dimensional channel model matrix
inversion based on the generated special sequence of channel states; and
vii) generates channel estimates based on the generated matrix inversion.