Method and apparatus for bidirectional demodulation of digitally modulated signals
First Claim
1. A method for demodulating data symbols transmitted through a communication channel comprising the steps of:
- sequentially receiving a plurality of first signal samples corresponding to predetermined data symbols, a second plurality of signal samples corresponding to unknown data symbols, and a third plurality of signal samples corresponding to a set of second predetermined data symbols;
storing the received pluralities of data samples;
determining first and second sets of reference signals from the stored pluralities of first and third signal samples, respectively;
forward-demodulating said unknown data symbols using said first set of reference signals beginning with signal samples received nearer said first plurality of signal samples;
backward-demodulating said unknown data symbols using said second set of reference signals beginning with signal samples received nearer said third plurality of signal samples;
determining quality values indicative of demodulation qualities of the forward- and backward-demodulated data symbols;
comparing the quality values; and
selecting either the forward- or backward-demodulated data symbols based on the comparison of quality values.
2 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for demodulating data symbols transmitted through a fading communication channel. A plurality of first predetermined data symbols, a plurality of unknown data symbols, and a plurality of second predetermined data symbols are sequentially received. The received pluralities of data symbols are stored, and first and second sets of reference signals from the stored pluralities of first and second predetermined data symbols, respectively, are determined. The stored unknown data symbols based on the first set of reference signals are forward-demodulated, beginning with unknown symbols received nearer the first predetermined data symbols. The stored unknown data symbols based on the second set of reference signals are backward-demodulated, beginning with the unknown data symbols received nearer the second predetermined data symbols. Quality values indicative of demodulation qualities of the forward- and backward-demodulated data symbols are determined. The quality values are compared, and either the forward- or backward-demodulated data symbols are selected based on the comparison of quality values.
83 Citations
19 Claims
-
1. A method for demodulating data symbols transmitted through a communication channel comprising the steps of:
-
sequentially receiving a plurality of first signal samples corresponding to predetermined data symbols, a second plurality of signal samples corresponding to unknown data symbols, and a third plurality of signal samples corresponding to a set of second predetermined data symbols; storing the received pluralities of data samples; determining first and second sets of reference signals from the stored pluralities of first and third signal samples, respectively; forward-demodulating said unknown data symbols using said first set of reference signals beginning with signal samples received nearer said first plurality of signal samples; backward-demodulating said unknown data symbols using said second set of reference signals beginning with signal samples received nearer said third plurality of signal samples; determining quality values indicative of demodulation qualities of the forward- and backward-demodulated data symbols; comparing the quality values; and selecting either the forward- or backward-demodulated data symbols based on the comparison of quality values.
-
-
2. An apparatus for demodulating data symbols transmitted through a communication channel comprising:
-
means for sequentially receiving a plurality of first predetermined data symbols, a plurality of unknown data symbols, and a plurality of second predetermined data symbols; means for storing the received pluralities of data symbols; means for determining first and second sets of reference signals from the stored pluralities of first and second predetermined data symbols, respectively; means for forward-demodulating the stored unknown data symbols based on the first set of reference signals beginning with unknown symbols received nearer the first predetermined data symbols; means for backward-demodulating the stored unknown data symbols based on the second set of reference signals beginning with the unknown data symbols received nearer the second predetermined data symbols; means for determining quality values indicative of demodulation qualities of the forward- and backward-demodulated data symbols; means for comparing the quality values; and means for selecting either the forward- or backward-demodulated data symbols based on the comparison of quality values. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
Specification