In high data rate communication applications where digital data
information is error-corrected coded and interleaved and transmitted with
spectral limitations over fading dispersive channels, a method and
receiver is described that incorporates channel estimation and
decision-feedback equalization. Channel estimation is accomplished within
a receiver time block with locally generated reference symbol sequences.
The parameters of the decision-feedback equalizer (DFE) are computed
directly from the channel estimates. The DFE is an optimum finite length
realization that includes effects from spectrum control filtering, a
space-time block coder (STBC) on multiple transmit antennas, multiple
receiver diversity signals, and the fading dispersive channel. The DFE
includes a matched filter, forward filter, backward filter, and detector.
A symbol combiner within the matched filter produces a P+1 dimensional
signal that provides ideal cancellation of P intersymbol interferers in
the forward filter. When P is selected to meet an intersymbol
interference (ISI) criterion, all desired signal energy is collected and
all ISI can be ideally cancelled. The DFE processes received signals
within the receiver time block to produce information symbol estimates
that are subsequently deinterleaved and error-correction decoded to
recover the transmitted digital data information. Deinterleaving over
multiple receiver time blocks further compensates for channel estimation
variations from block to block. Additionally the STBC and DFE are used in
a quadruple angle diversity technique requiring only a single antenna at
each terminal of a troposcatter link to provide performance approaching
that of a nonfading satellite link.