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US 7,257,102 B2Granted
Carrier frequency offset estimation from preamble symbols
AssigneeBroadcom Corporation
InventorsJonathan S. Min, Nabil R. Yousef
Life of this patent
Estimating the term…
Abstract
Carrier frequency offset (CFO) estimation from preamble symbols. Any communication receiver may be adapted to perform the CFO estimation. The CFO estimation is performed using a low complexity, high accuracy CFO estimation method. The operation may be described as follows: each element of a received sequence is divided by the corresponding preamble element, the resulting sequence is divided into N subgroups, and each subgroup is then averaged. The phase differential of the resulting sequence is computed, averaged, and used to compute an estimate of the carrier frequency offset. This approach to performing CFO estimation is of relatively high estimation accuracy and of relatively low computational complexity.
Claims38
An apparatus, comprising:
- a communication receive channel that is operable to receive a data packet that includes a preamble sequence, the preamble sequence includes a plurality of preamble symbols;
- and
- a carrier frequency offset estimation functional block that is operable to extract the preamble sequence from the data packet;
- and wherein:
- the carrier frequency offset estimation functional block is operable to modify the preamble sequence, using an expected preamble sequence, thereby generating an intermediate preamble sequence;
- the carrier frequency offset estimation functional block is operable to generate a plurality of phase differentials such that each phase differential corresponds to two elements of the intermediate preamble sequence;
- and
- the carrier frequency offset estimation functional block is operable to use the plurality of phase differentials to estimate a carrier frequency offset in the received data packet.
5 more elements
A communication receiver, comprising:
- a communication receive channel that is operable to receive a sequence comprising a plurality of preamble symbols;
- and
- a carrier frequency offset estimation functional block that is operable to modify the plurality of preamble symbols, using a plurality of expected preamble symbols, to generate an plurality of intermediate preamble symbols;
- wherein the carrier frequency offset estimation functional block subgroups the plurality of intermediate preamble symbols into a plurality of subgroups;
- the carrier frequency offset estimation functional block calculates an average for each of the subgroups of the plurality of subgroups thereby generating a plurality of subgroup averages;
- the carrier frequency offset estimation functional block calculates a phase differential between each subgroup average within the plurality of subgroup averages thereby generating a plurality of phase differentials;
- and
- the carrier frequency offset estimation functional block uses the plurality of phase differentials to estimate a carrier frequency offset in the received sequence.
5 more elements
A multi-channel headend physical layer burst receiver, comprising:
- a time division multiple access receive channel that is operable to receive a time division multiple access data packet;
- a code division multiple access receive channel that is operable to receive a code division multiple access data packet;
- a carrier frequency offset estimation functional block that is operable to extract a preamble sequence from at least one of the time division multiple access data packet and the code division multiple access data packet;
- and
- wherein the carrier frequency offset estimation functional block is operable to modify the preamble sequence, using an expected preamble sequence, to generate an intermediate preamble sequence;
- the carrier frequency offset estimation functional block subgroups the intermediate preamble sequence into a plurality of subgroups;
- the carrier frequency offset estimation functional block calculates an average for each of the subgroups of the plurality of subgroups thereby generating a plurality of subgroup averages;
- the carrier frequency offset estimation functional block calculates a phase differential between each subgroup average within the plurality of subgroup averages thereby generating a plurality of phase differentials;
- the carrier frequency offset estimation functional block uses the plurality of phase differentials to estimate a carrier frequency offset in at least one of the time division multiple access data packet and the code division multiple access data packet;
- and
- the carrier frequency offset estimation functional block considers an interleaving depth of at least one of the time division multiple access data packet and the code division multiple access data packet when estimating the carrier frequency offset in at least one of the time division multiple access data packet and the code division multiple access data packet.
8 more elements
A method, comprising:
- receiving a data packet comprising a preamble sequence, the preamble sequence including a plurality of preamble symbols;
- extracting the preamble sequence from the data packet;
- modifying the preamble sequence, using an expected preamble sequence, to generate an intermediate preamble sequence;
- generating a plurality of phase differentials such that each phase differential corresponds to two elements of the intermediate preamble sequence;
- and
- employing the plurality of phase differentials to estimate a carrier frequency offset in the received data packet.
3 more elements
A carrier frequency offset estimation method, comprising:
- receiving a sequence comprising a plurality of preamble symbols;
- modifying the plurality of preamble symbols, using a plurality of expected preamble symbols, to generate an plurality of intermediate preamble symbols;
- subgrouping the plurality of intermediate preamble symbols into a plurality of subgroups;
- calculating an average for each of the subgroups of the plurality of subgroups thereby generating a plurality of subgroup averages;
- calculating a phase differential between each subgroup average within the plurality of subgroup averages thereby generating a plurality of phase differentials;
- and
- employing the plurality of phase differentials to estimate a carrier frequency offset in the received sequence.
4 more elements
A carrier frequency offset estimation method, comprising:
- receiving at least one of a time division multiple access data packet and a code division multiple access data packet;
- extracting a preamble sequence from at least one of the time division multiple access data packet and the code division multiple access data packet;
- modifying the preamble sequence, using an expected preamble sequence, to generate an intermediate preamble sequence;
- subgrouping the intermediate preamble sequence into a plurality of subgroups;
- calculating an average for each of the subgroups of the plurality of subgroups thereby generating a plurality of subgroup averages;
- calculating a phase differential between each subgroup average within the plurality of subgroup averages thereby generating a plurality of phase differentials;
- employing the plurality of phase differentials to estimate a carrier frequency offset in at least one of the time division multiple access data packet and the code division multiple access data packet;
- and
- considering an interleaving depth of at least one of the time division multiple access data packet and the code division multiple access data packet when estimating the carrier frequency offset in at least one of the time division multiple access data packet and the code division multiple access data packet.
6 more elements
Dependencies are inferred from the claim text.