Pilot transmission and channel estimation for MISO and MIMO receivers in a multi-antenna system

A method of transmitting a pilot in a wireless communication system, comprising:

• generating a plurality of composite pilots with a first matrix and a second matrix, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of the first matrix and scaled with a plurality of gain elements in a column of the second matrix;
• and
• transmitting each of the plurality of composite pilots via a plurality of transmit antennas,
• wherein the generating the plurality of composite pilots comprises generating the plurality of composite pilots with the first matrix, the second matrix, and a plurality of third matrices for a plurality of frequency subbands, the plurality of third matrices providing diversity for the plurality of composite pilots.

A method of transmitting a pilot in a wireless communication system, comprising:

• generating a plurality of composite pilots with a first matrix and a second matrix, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of the first matrix and scaled with a plurality of gain elements in a column of the second matrix;
• and
• transmitting each of the plurality of composite pilots via a plurality of transmit antennas,
• wherein the transmitting each of the plurality of composite pilots comprises transmitting each composite pilot in a different symbol period and via the plurality of transmit antennas.

A method of transmitting a pilot in a wireless communication system, comprising:

• generating a plurality of composite pilots with a first matrix and a second matrix, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of the first matrix and scaled with a plurality of gain elements in a column of the second matrix;
• and
• transmitting each of the plurality of composite pilots via a plurality of transmit antennas,
• wherein the transmitting each of the plurality of composite pilots comprises transmitting each composite pilot on a plurality of frequency subbands and via the plurality of transmit antennas.

A method of transmitting a pilot in a wireless communication system, comprising:

• generating a first composite pilot with a training matrix and a first gain vector, the first composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of the training matrix and scaled with a plurality of gain elements in the first gain vector;
• selectively generating at least one additional composite pilot with the training matrix and at least one additional gain vector;
• and
• transmitting the first composite pilot and the at least one additional composite pilot, if generated, via a plurality of transmit antennas,
• wherein the plurality of gain elements of the first gain vector and the at least one additional gain vector, if selectively generated, are used with the training matrix to estimate a multiple-input single-output channel.

An apparatus in a wireless communication system, comprising:

• a pilot generator operative to generate a plurality of composite pilots with a first matrix and a second matrix, each composite pilot comprising a plurality of training pilots generated with a plurality of columns of the first matrix and scaled with a plurality of gain elements in a column of the second matrix;
• and
• a plurality of transmitter units operative to transmit each of the plurality of composite pilots via a plurality of transmit antennas,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate a multiple-input single-output channel.

An apparatus in a wireless communication system, comprising:

• means for generating a plurality of composite pilots with a first matrix and a second matrix, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of the first matrix and scaled with a plurality of gain elements in a column of the second matrix;
• and
• means for transmitting each of the plurality of composite pilots via a plurality of transmit antennas,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate a multiple-input single-output channel.

A method of performing channel estimation in a wireless communication system, comprising:

• obtaining, via a single receive antenna, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• processing the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate the multiple-input single-output channel.

A method of performing channel estimation in a wireless communication system, comprising:

• obtaining, via a single receive antenna, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• processing the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the processing the received symbols comprises filtering the received symbols to obtain the estimate of the MISO channel.

A method of performing channel estimation in a wireless communication system, comprising:

• obtaining, via a single receive antenna, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• processing the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the processing the received symbols comprises deriving a plurality of initial impulse response estimates for the plurality of composite pilots based on the received symbols, and filtering the plurality of initial impulse response estimates to obtain an impulse response estimate for the MISO channel.

An apparatus in a wireless communication system, comprising:

• a receiver unit operative to provide received symbols for a plurality of composite pilots transmitted from a plurality of transmit antennas to a single receive antenna, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• a channel estimator operative to process the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate the multiple-input single-output channel.

An apparatus in a wireless communication system, comprising:

• a receiver unit operative to provide received symbols for a plurality of composite pilots transmitted from a plurality of transmit antennas to a single receive antenna, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• a channel estimator operative to process the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the channel estimator is operative to filter the received symbols to obtain the estimate of the MISO channel.

An apparatus in a wireless communication system, comprising:

• a receiver unit operative to provide received symbols for a plurality of composite pilots transmitted from a plurality of transmit antennas to a single receive antenna, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• a channel estimator operative to process the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the channel estimator is operative to derive a plurality of initial impulse response estimates for the plurality of composite pilots based on the received symbols and to filter the plurality of initial impulse response estimates to obtain an impulse response estimate for the MISO channel.

An apparatus in a wireless communication system, comprising:

• means for obtaining, via a single receive antenna, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• means for processing the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate the multiple-input single-output channel.

An apparatus in a wireless communication system, comprising:

• means for obtaining, via a single receive antenna, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• means for processing the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the means for processing the received symbols comprises means for filtering the received symbols to obtain the estimate of the MISO channel.

An apparatus in a wireless communication system, comprising:

• means for obtaining, via a single receive antenna, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• means for processing the received symbols to obtain an estimate of a multiple-input single-output (MISO) channel between the plurality of transmit antennas and the single receive antenna,
• wherein the means for processing the received symbols comprises means for deriving a plurality of initial impulse response estimates for the plurality of composite pilots based on the received symbols, and means for filtering the plurality of initial impulse response estimates to obtain an impulse response estimate for the MISO channel.

A method of performing channel estimation in a wireless communication system, comprising:

• obtaining, via a plurality of receive antennas, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• processing the received symbols based on the first and second matrices to obtain estimates of a plurality of single-input single-output (SISO) channels between the plurality of transmit antennas and the plurality of receive antennas,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate a multiple-input single-output channel.

A method of performing channel estimation in a wireless communication system, comprising:

• obtaining, via a plurality of receive antennas, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• processing the received symbols based on the first and second matrices to obtain estimates of a plurality of single-input single-output (SISO) channels between the plurality of transmit antennas and the plurality of receive antennas,
• wherein the processing the received symbols comprises deriving a plurality of initial impulse response estimates for a plurality of combinations of composite pilot and receive antenna based on the received symbols, and processing the plurality of initial impulse response estimates based on the first and second matrices to obtain a plurality of intermediate impulse response estimates for the plurality of SISO channels,
• wherein the processing the received symbols further comprises delaying the plurality of intermediate impulse response estimates based on delays introduced at the plurality of transmit antennas.

A method of performing channel estimation in a wireless communication system, comprising:

• obtaining, via a plurality of receive antennas, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• processing the received symbols based on the first and second matrices to obtain estimates of a plurality of single-input single-output (SISO) channels between the plurality of transmit antennas and the plurality of receive antennas,
• wherein the processing the received symbols comprises deriving a plurality of initial impulse response estimates for a plurality of combinations of composite pilot and receive antenna based on the received symbols, and processing the plurality of initial impulse response estimates based on the first and second matrices to obtain a plurality of intermediate impulse response estimates for the plurality of SISO channels,
• wherein the processing the received symbols further comprises deriving a plurality of frequency response estimates for the plurality of SISO channels based on the plurality of intermediate impulse response estimates.

A method of performing channel estimation in a wireless communication system, comprising:

• obtaining, via a plurality of receive antennas, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• processing the received symbols based on the first and second matrices to obtain estimates of a plurality of single-input single-output (SISO) channels between the plurality of transmit antennas and the plurality of receive antennas,
• wherein the processing the received symbols comprises processing the received symbols based on the first and second matrices to obtain a plurality of initial frequency response estimates for the plurality of SISO channels, deriving a plurality of impulse response estimates for the plurality of SISO pilots based on the plurality of initial frequency response estimates, and deriving a plurality of final frequency response estimates for the plurality of SISO channels based on the plurality of impulse response estimates.

An apparatus in a wireless communication system, comprising:

• a plurality of receiver units operative to provide received symbols for a plurality of composite pilots transmitted from a plurality of transmit antennas to a plurality of receive antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• a channel estimator operative to process the received symbols based on the first and second matrices to obtain estimates of a plurality of single-input single-output (SISO) channels between the plurality of transmit antennas and the plurality of receive antennas,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate a multiple-input single-output channel.

An apparatus in a wireless communication system, comprising:

• a plurality of receiver units operative to provide received symbols for a plurality of composite pilots transmitted from a plurality of transmit antennas to a plurality of receive antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• a channel estimator operative to process the received symbols based on the first and second matrices to obtain estimates of a plurality of single-input single-output (SISO) channels between the plurality of transmit antennas and the plurality of receive antennas,
• wherein the channel estimator is operative to derive a plurality of initial impulse response estimates for a plurality of combinations of composite pilot and receive antenna based on the received symbols and to process the plurality of initial impulse response estimates based on the first and second matrices to obtain a plurality of intermediate impulse response estimates for the plurality of SISO channels.

An apparatus in a wireless communication system, comprising:

• means for obtaining, via a plurality of receive antennas, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• means for processing the received symbols based on the first and second matrices to obtain estimates of a plurality of single-input single-output (SISO) channels between the plurality of transmit antennas and the plurality of receive antennas,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate a multiple-input single-output channel.

An apparatus in a wireless communication system, comprising:

• means for obtaining, via a plurality of receive antennas, received symbols for a plurality of composite pilots transmitted via a plurality of transmit antennas, each composite pilot comprising a plurality of training pilots generated with a plurality of columns of a first matrix and scaled with a plurality of gain elements in a column of a second matrix;
• and
• means for processing the received symbols based on the first and second matrices to obtain estimates of a plurality of single-input single-output (SISO) channels between the plurality of transmit antennas and the plurality of receive antennas,
• wherein the means for processing the received symbols comprises means for deriving a plurality of initial impulse response estimates for a plurality of combinations of composite pilot and receive antenna based on the received symbols, and means for processing the plurality of initial impulse response estimates based on the first and second matrices to obtain a plurality of intermediate impulse response estimates for the plurality of SISO channels.

A non-transitory computer-readable medium having a computer program, which when executed by at least one processor, operates to transmit a pilot in a wireless communication system, the computer program comprising:

• instructions for generating a plurality of composite pilots with a first matrix and a second matrix, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of the first matrix and scaled with a plurality of gain elements in a column of the second matrix;
• and
• instructions for transmitting each of the plurality of composite pilots via a plurality of transmit antennas,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate a multiple-input single-output channel.

At least one processor configured to perform a method of transmitting a pilot in a wireless communication system, the method comprising:

• generating a plurality of composite pilots with a first matrix and a second matrix, each composite pilot comprising a plurality of training pilots generated with a plurality of orthogonal columns of the first matrix and scaled with a plurality of gain elements in a column of the second matrix;
• and
• transmitting each of the plurality of composite pilots via a plurality of transmit antennas,
• wherein the plurality of gain elements of the second matrix are used with the first matrix to estimate a multiple-input single-output channel.