Method and apparatus for channel estimation for multicarrier systems

A method for processing multicarrier signal in a receiver, the method comprising the steps of:

• receiving a multicarrier signal at each of a plurality of antennas from a plurality of channels to provide a plurality of receiver inputs;
• modifying the receiver inputs in accordance with an estimate of characteristics of the plurality of channels;
• combining the modified receiver inputs;
• and
• generating a reference signal for estimating channel characteristics using a signal based on the combination of the modified receiver inputs, where said estimate of characteristics of the plurality of channels is generated in accordance with the substeps of;
• generating a temporal estimate of channel characteristics based on the plurality of receiver inputs and the reference signal,
• transforming in the frequency-domain the temporal estimate of channel characteristics,
• time-filtering the transformed temporal estimate, and
• transforming in the frequency domain the output of the step of time filtering.

An apparatus for receiving a signal stream of a multicarrier signal, the apparatus comprising:

• a plurality of antennas;
• a channel estimator coupled to said plurality of antennas, said channel estimator including
• a first frequency domain transformer,
• a time-domain filter coupled to said first frequency-domain transformer, and
• a second frequency-domain transformer coupled to said time-domain filter,
• received signal adjusters coupled to said channel estimator;
• a combiner coupled to said received signal adjusters;
• a reference generator having an input coupled to said combiner and an output coupled to said channel estimator.

An apparatus for estimating channel characteristics in a multicarrier transmission system, the apparatus comprising:

• a first frequency-domain transformer, transforming from the frequency domain to the time-domain, wherein said first frequency domain transformer comprises a unitary linear inverse transformer;
• a time-domain filter coupled to said frequency-domain transformer, wherein said time-domain filter includes coefficients selected to match a maximum delay spread;
• and
• a second frequency-domain transformer, transforming from the time-domain to the frequency domain, coupled to an output of said time-domain filter.

An apparatus for estimating channel characteristics in a multicarrier transmission system, the apparatus comprising:

• a first frequency-domain transformer, transforming from the frequency domain to the time-domain, wherein said first frequency domain transformer comprises a unitary linear inverse transformer;
• a time-domain filter coupled to said frequency-domain transformer, wherein said time-domain filter includes coefficients selected to match a rectangular spectrum;
• and
• a second frequency-domain transformer, transforming from the time-domain to the frequency domain, coupled to an output of said time-domain filter.

An apparatus for estimating channel characteristics in a multicarrier transmission system, the apparatus comprising:

• a first frequency-domain transformer, transforming from the frequency domain to the time-domain;
• a time-domain filter coupled to said frequency-domain transformer, wherein said time-domain filter includes coefficients selected to match a maximum delay spread;
• and
• a second frequency-domain transformer, transforming from the time-domain to the frequency domain, coupled to an output of said time-domain filter.

An apparatus for estimating channel characteristics in a multicarrier transmission system, the apparatus comprising:

• a first frequency-domain transformer, transforming from the frequency domain to the time-domain;
• a time-domain filter coupled to said frequency-domain transformer, wherein said time-domain filter includes coefficients selected to match a rectangular spectrum;
• and
• a second frequency-domain transformer, transforming from the time-domain to the frequency domain, coupled to an output of said time-domain filter.