Channel estimation for multi-carrier communication

A method comprising:

• identify, for identifying a set of selected channel taps, at least one index of a plurality of channel taps in a channel impulse response estimate based on a scattered pilot having a pilot symbol on each of a plurality of interlaces corresponding to a first plurality of carriers, wherein the selected channel taps are a predetermined number of strongest channel taps;
• determining gains of the selected channel taps based on a continual pilot having a pilot symbol on each of a second plurality of carriers;
• deriving a channel frequency response estimate based on the gains of the selected channel taps;
• performing data detection with the channel frequency response estimate;
• and
• combining, in a frequency domain, the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot, wherein the combining comprises:
• receiving pilot symbols on the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot in a plurality of symbol periods,
• combining the received pilot symbols in frequency domain in accordance with a plurality of coefficients, and
• deriving the channel impulse response estimate based on the combined pilot symbols, wherein the coefficients determine weights applied to the plurality of interlaces for combining.

An apparatus comprising:

• a scattered pilot channel estimator for identifying a set of selected channel taps to identify at least one index of a plurality of channel taps in a channel impulse response estimate based on a scattered pilot having a pilot symbol on each of a plurality of interlaces corresponding to a first plurality of carriers for identifying a set of selected channel taps, wherein the selected channel taps are a predetermined number of strongest channel taps;
• a continuous pilot channel estimator for determining gains of the selected channel taps based on a continual pilot having a pilot symbol on each of a second plurality of carriers;
• a post-processor for deriving a channel frequency response estimate based on the gains of the selected channel taps and for performing data detection with the channel frequency response estimate;
• and
• wherein the scattered pilot channel estimator further combines, in a frequency domain, the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot, wherein the combining comprises:
• receiving pilot symbols on the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot in a plurality of symbol periods,
• combining the received pilot symbols in frequency domain in accordance with a plurality of coefficients, and
• deriving the channel impulse response estimate based on the combined pilot symbols, wherein the coefficients determine weights applied to the plurality of interlaces for combining.

A non-transitory processor readable media for storing instructions executable by a processor;

• the instructions, when executed, are operable to:
• identify, for identifying a set of selected channel taps, at least one index of a plurality of channel taps in a channel impulse response estimate based on a scattered pilot having a pilot symbol on each of a plurality of interlaces corresponding to a first plurality of carriers for identifying a set of selected channel taps, wherein the selected channel taps are a predetermined number of strongest channel taps;
• determine gains of the selected channel taps based on a continual pilot having a pilot symbol on each of a second plurality of carriers;
• derive a channel frequency response estimate based on the gains of the selected channel taps;
• perform data detection with the channel frequency response estimate;
• and
• combine, in a frequency domain, the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot, wherein the combining comprises:
• receiving pilot symbols on the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot in a plurality of symbol periods,
• combining the received pilot symbols in frequency domain in accordance with a plurality of coefficients, and
• deriving the channel impulse response estimate based on the combined pilot symbols, wherein the coefficients determine weights applied to the plurality of interlaces for combining.

An apparatus comprising:

• at least one processor;
• a memory coupled to the at least one processor;
• the at least one processor configured to:
• identify, for identifying a set of selected channel taps, at least one index of a plurality of channel taps in a channel impulse response estimate based on a scattered pilot having a pilot symbol on each of a plurality of interlaces corresponding to a first plurality of carriers;
• determine gains of the selected channel taps based on a continual pilot having a pilot symbol on each of a second plurality of carriers, wherein the selected channel taps are a predetermined number of strongest channel taps;
• derive a channel frequency response estimate based on the gains of the selected channel taps;
• perform data detection with the channel frequency response estimate;
• and
• combine, in a time domain, the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot, wherein the combining comprises:
• receiving pilot symbols in each of a plurality of symbol periods for the scattered pilot,
• deriving an initial channel impulse response estimate for each symbol period based on the received pilot symbols for the each of the said plurality of symbol periods, and
• filtering initial channel impulse response estimates for said plurality of symbol periods to obtain the channel impulse response estimate.

A method comprising:

• identifying at least one index of a plurality of channel taps, for identifying a set of selected channel taps, in a channel impulse response estimate based on a scattered pilot having a pilot symbol on each of a plurality of interlaces corresponding to a first plurality of carriers, wherein the selected channel taps are a predetermined number of strongest channel taps;
• determining gains of the selected channel taps based on a continual pilot having a pilot symbol on each of a second plurality of carriers;
• deriving a channel frequency response estimate based on the gains of the selected channel taps;
• performing data detection with the channel frequency response estimate;
• and
• combining, in a frequency domain, the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot, wherein the combining comprises:
• receiving pilot symbols on the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot in a plurality of symbol periods,
• combining the received pilot symbols in frequency domain in accordance with a plurality of coefficients, and
• deriving the channel impulse response estimate based on the combined pilot symbols, wherein the coefficients determine weights applied to the plurality of interlaces for combining.

An apparatus comprising:

• a scattered pilot channel estimator for identifying a set of selected channel taps to identify at least one index of a plurality of channel taps in a channel impulse response estimate based on a scattered pilot having a pilot symbol on each of a plurality of interlaces corresponding to a first plurality of carriers for identifying a set of selected channel taps, wherein the selected channel taps are a predetermined number of strongest channel taps;
• a continuous pilot channel estimator for determining gains of the selected channel taps based on a continual pilot having a pilot symbol on each of a second plurality of carriers;
• a post-processor for deriving a channel frequency response estimate based on the gains of the selected channel taps and for performing data detection with the channel frequency response estimate;
• and
• wherein the scattered pilot channel estimator further combines the scattered pilot interlaces in a time domain, wherein combining in the time domain comprises:
• receiving pilot symbols in each of a plurality of symbol periods for the scattered pilot,
• deriving an initial channel impulse response estimate for each symbol period based on the received pilot symbols for the each of the said plurality of symbol periods, and
• filtering initial channel impulse response estimates for said plurality of symbol periods to obtain the channel impulse response estimate.

A non-transitory processor readable media for storing instructions executable by a processor;

• the instructions, when executed, are operable to:
• identify, for identifying a set of selected channel taps, at least one index of a plurality of channel taps in a channel impulse response estimate based on a scattered pilot having a pilot symbol on each of a plurality of interlaces corresponding to a first plurality of carriers;
• determine gains of the selected channel taps based on a continual pilot having a pilot symbol on each of a second plurality of carriers, wherein the selected channel taps are a predetermined number of strongest channel taps;
• derive a channel frequency response estimate based on the gains of the selected channel taps;
• perform data detection with the channel frequency response estimate;
• and
• combine, in a time domain, the plurality of interlaces corresponding to the first plurality of carriers carrying the scattered pilot, wherein the combining comprises:
• receiving pilot symbols in each of a plurality of symbol periods for the scattered pilot,
• deriving an initial channel impulse response estimate for each symbol period based on the received pilot symbols for the each of the said plurality of symbol periods, and
• filtering initial channel impulse response estimates for said plurality of symbol periods to obtain the channel impulse response estimate.