| US 7,499,392 B2 | ||
| OFDM equalizer filter with shared multiplier | ||
| David Lawrence Albean, Indianapolis, Ind. (US) | ||
| Assigned to Thomson Licensing, Boulogne, Billancourt (France) | ||
| Appl. No. 10/514,090 PCT Filed May 08, 2003, PCT No. PCT/US03/14506 § 371(c)(1), (2), (4) Date Nov. 10, 2004, PCT Pub. No. WO03/098854, PCT Pub. Date Nov. 27, 2003. |
||
| Claims priority of provisional application 60/380621, filed on May 15, 2002. | ||
| Prior Publication US 2005/0185573 A1, Aug. 25, 2005 | ||
| Int. Cl. H04J 11/00 (2006.01) | ||
| U.S. Cl. 370—206 [370/343] | 4 Claims |

| 1. An apparatus for OFDM communications, the apparatus comprising:
an equalizer filter configured to receive input data and to apply a tap setting to the input data to generate output data,
the equalizer filter including:
a first multiplexer including a first data input, a second data input, a first data output, and a first control input, the
first multiplexer arranged to receive a real component of the tap setting at the first data input, arranged to receive an
imaginary component of the tap setting at the second data input, arranged to receive a control signal at the first control
input, configured to provide the real component of the tap setting at the first data output in response to a first state of
the control signal, and configured to provide the imaginary component of the tap setting at the first data output in response
to a second state of the control signal,
a first multiplier including a third data input, a fourth data input coupled to the data output of the first multiplexer,
and a second data output, the first multiplier arranged to receive a real component of the input data at the third data input,
arranged to receive the provided one of the real component of the tap setting and the imaginary component of the tap setting
at the fourth data input, and configured to provide a first result at the second data output, the first result corresponding
to a multiplication of data received at the third data input by data received at the fourth data input,
a second multiplexer including a fifth data input, a sixth data input, a third data output, and a second control input coupled
to the control input of the first multiplexer, the second multiplexer arranged to receive the imaginary component of the tap
setting at the fifth data input, arranged to receive the real component of the tap setting at the sixth data input, arranged
to receive the control signal at the second control input, configured to provide the imaginary component of the tap setting
at the third data output in response to the first state of the control signal, and configured to provide the real component
of the tap setting at the third data output in response to the second state of the control signal,
a second multiplier including a seventh data input, an eighth data input coupled to the data output of the second multiplexer,
and a fourth data output, the second multiplier arranged to receive an imaginary component of the input data at the seventh
data input, arranged to receive the provided one of the imaginary component of the tap setting and the real component of the
tap setting at the eighth data input, and configured to provide a second result at the fourth data output, the second result
corresponding to a multiplication of data received at the seventh data input by data received at the eighth data input,
an inverter including a ninth data input coupled to the data output of the second multiplier and further including a fifth
data output, the inverter configured to provide a third result at the fifth data output, the third result corresponding to
a magnitude of data received at the ninth data input and an opposite sign from the data received at the ninth data input,
a third multiplexer including a tenth data input coupled the data output of the inverter, an eleventh data input coupled to
the data output of the second multiplier, a sixth data output, and a third control input coupled to the control input of the
first multiplexer and the control input of the second multiplexer, the third multiplexer arranged to receive the control signal
at the third control input, configured to provide data received at the tenth data input at the sixth data output in response
to the first state of the control signal, and configured to provide data received at the eleventh data input at the sixth
data output in response to the second state of the control signal, and
a summer including a twelfth data input coupled to the data output of the first multiplier, a thirteenth data input coupled
to the data output of the third multiplexer, and a seventh data output, the summer configured to provide the output data at
the seventh data output, the output data including a plurality of pairs of time-multiplexed components, each pair including
exactly one real component and exactly one imaginary component.
|