US 7,742,546 B2 · Receiver spatial processing for eigenmode transmission in a MIMO system

Abstract

For eigenmode transmission with minimum mean square error (MMSE) receiver spatial processing, a transmitter performs spatial processing on NS data symbol streams with steering vectors to transmit the streams on NS spatial channels of a MIMO channel. The steering vectors are estimates of transmitter steering vectors required to orthogonalize the spatial channels. A receiver derives a spatial filter based on an MMSE criterion and with an estimate of the MIMO channel response and the steering vectors. The receiver (1) obtains NR received symbol streams from NR receive antennas, (2) performs spatial processing on the received symbol streams with the spatial filter to obtain NS filtered symbol streams, (3) performs signal scaling on the filtered symbol streams with a scaling matrix to obtain NS recovered symbol streams, and (4) processes the NS recovered symbol streams to obtain NS decoded data streams for the NS data streams sent by the transmitter.

Claims31

Dependent claims

A method of performing spatial processing at a receiver in a wireless multiple-input multiple-output (MIMO) communication system, comprising:

obtaining a plurality of received symbol streams for a plurality of data symbol streams sent via a plurality of spatial channels of a MIMO channel in the wireless MIMO communication system, wherein spatial processing is performed at a transmitter with steering vectors, which are estimates of transmitter steering vectors required to orthogonalize the plurality of spatial channels;
receiving orthogonal pilot transmissions from a plurality of antennas at the transmitter;
obtaining an estimate of a channel response matrix for the MIMO channel, wherein the estimated channel response matrix is obtained based on the received orthogonal pilot transmissions;
and
performing spatial processing on the plurality of received symbol streams with a spatial filter to obtain a plurality of filtered symbol streams, which are estimates of the plurality of data symbol streams, wherein the spatial filter has a response derived based on a minimum mean square error (MMSE) criterion that minimizes mean square error between the plurality of filtered symbol streams and the plurality of data symbol streams, wherein the spatial filter response is derived in accordance with the following formula:
W={circumflex over (V)}HĤH[Ĥ{circumflex over (V)}{circumflex over (V)}HĤH +ønn]-1,
where W is the spatial filter response,
{circumflex over (V)} is a matrix of the steering vectors used for spatial processing at the transmitter,
Ĥ is the estimated channel response matrix,
{circumflex over (V)}H and ĤH denote the Hermitian or conjugate transpose of {circumflex over (V)} and Ĥ respectively, and
ønn is an autocovariance matrix of noise at the receiver.

8 more elements

A receiver in a wireless multiple-input multiple-output (MIMO) communication system, comprising:

a receiver unit operative to receive orthogonal pilot transmissions from a plurality of antennas at a transmitter, the receiver unit also operative to obtain a plurality of received symbol streams for a plurality of data symbol streams sent via a plurality of spatial channels of a MIMO channel in the wireless MIMO communication system, wherein spatial processing is performed at a transmitter with steering vectors, which are estimates of transmitter steering vectors required to orthogonalize the plurality of spatial channels;
a channel estimator operative to obtain an estimate of a channel response matrix for the MIMO channel, wherein the estimated channel response matrix is obtained based on the received orthogonal pilot transmissions;
and,
a spatial filter operative to spatially process the plurality of received symbol streams to obtain a plurality of filtered symbol streams, which are estimates of the plurality of data symbol streams, wherein the spatial filter has a response derived based on a minimum mean square error (MMSE) criterion that minimizes mean square error between the plurality of filtered symbol streams and the plurality of data symbol streams,
wherein the spatial filter response is derived in accordance with the following formula:
W={circumflex over (V)}H ĤH [Ĥ{circumflex over (V)}{circumflex over (V)}H ĤH+ønn]-1,
where W is the spatial filter response,
{circumflex over (V)} is a matrix of the steering vectors used for spatial processing at the transmitter,
Ĥ if the estimated channel response matrix,
{circumflex over (V)}H and ĤH denote the Hermitian or conjugate transpose of {circumflex over (V)} and Ĥ respectively, and
ønn is an autocovariance matrix of noise at the receiver.

8 more elements

A receiver apparatus in a wireless multiple-input multiple-output (MIMO) communication system, comprising:

means for obtaining a plurality of received symbol streams for a plurality of data symbol streams sent via a plurality of spatial channels of a MIMO channel in the wireless MIMO communication system, wherein spatial processing is performed at a transmitter with steering vectors, which are estimates of transmitter steering vectors required to orthogonalize the plurality of spatial channels;
means for receiving orthogonal pilot transmissions from a plurality of antennas at the transmitter;
means for obtaining an estimate of a channel response matrix for the MIMO channel, wherein the estimated channel response matrix is obtained based on the received orthogonal pilot transmissions;
and
means for performing spatial processing on the plurality of received symbol streams with a spatial filter to obtain a plurality of filtered symbol streams, which are estimates of the plurality of data symbol streams, wherein the spatial filter has a response derived based on a minimum mean square error (MMSE) criterion that minimizes mean square error between the plurality of filtered symbol streams and the plurality of data symbol,
wherein the spatial filter response is derived in accordance with the following formula:
W={circumflex over (V)}HĤH[Ĥ{circumflex over (V)}{circumflex over (V)}HĤH+ønn]-1,
where W is the spatial filter response,
{circumflex over (V)} is a matrix of the steering vectors used for spatial processing at the transmitter,
Ĥ is the estimated channel response matrix,
{circumflex over (V)}H and ĤH denote the Hermitian or conjugate transpose of {circumflex over (V)} and Ĥ respectively, and
ønn is an autocovariance matrix of noise at the receiver.

9 more elements

A method of performing spatial processing at a transmitter in a wireless multiple-input multiple-output (MIMO) communication system, comprising:

obtaining a plurality of data symbol streams for transmission on a plurality of spatial channels of a MIMO channel in the wireless MIMO communication system;
obtaining an estimate of a plurality of steering vectors, wherein the plurality of steering vectors is based on received orthogonal pilot transmissions;
and
performing spatial processing on the plurality of data symbol streams with the plurality of steering vectors, one steering vector for each data symbol stream, to obtain a plurality of transmit symbol streams for transmission from a plurality of transmit antennas, wherein the plurality of steering vectors are estimates of transmitter steering vectors required to orthogonalize the plurality of spatial channels, and
wherein the plurality of data symbol streams are recovered at a receiver with a spatial filter having a response derived based on a minimum mean square error (MMSE) criterion that minimizes mean square error between a plurality of filtered symbol streams from the spatial filter and the plurality of data symbol streams,
W={circumflex over (V)}HĤH[Ĥ{circumflex over (V)}{circumflex over (V)}HĤH+ønn]-1,
where W is the spatial filter response,
{circumflex over (V)} is a matrix of the steering vectors used for spatial processing at the transmitter,
Ĥ is the estimated channel response matrix,
{circumflex over (V)}H and ĤH denote the Hermitian or conjugate transpose of {circumflex over (V)} and Ĥ respectively, and
ønn is an autocovariance matrix of noise at the receiver.

8 more elements

A transmitter in a wireless multiple-input multiple-output (MIMO) communication system, comprising:

a transmit data processor operative to process a plurality of data streams and provide a plurality of data symbol streams for transmission on a plurality of spatial channels of a MIMO channel in the wireless MIMO communication system;
an estimator operative to obtain an estimate of a plurality of steering vectors, wherein the plurality of steering vectors is based on received orthogonal pilot transmissions;
and
a transmit spatial processor operative to perform spatial processing on the plurality of data symbol streams with the plurality of steering vectors, one steering vector for each data symbol stream, to obtain a plurality of transmit symbol streams for transmission from a plurality of transmit antennas, wherein the plurality of steering vectors are estimates of transmitter steering vectors required to orthogonalize the plurality of spatial channels, and
wherein the plurality of data symbol streams are recovered at a receiver with a spatial filter having a response derived based on a minimum mean square error (MMSE) criterion that minimizes mean square error between a plurality of filtered symbol streams from the spatial filter and the plurality of data symbol streams,
W={circumflex over (V)}HĤH[Ĥ{circumflex over (V)}{circumflex over (V)}HĤH+ønn]-1,
where W is the spatial filter response,
{circumflex over (V)} is a matrix of the steering vectors used for spatial processing at the transmitter,
Ĥ is the estimated channel response matrix,
{circumflex over (V)}H and ĤH denote the Hermitian or conjugate transpose of {circumflex over (V)} and Ĥ respectively, and
ønn is an autocovariance matrix of noise at the receiver.

8 more elements

A transmitter apparatus in a wireless multiple-input multiple-output (MIMO) communication system, comprising:

means for obtaining a plurality of data symbol streams for transmission on a plurality of spatial channels of a MIMO channel in the wireless MIMO communication system
means for obtaining an estimate of a plurality of steering vectors, wherein the plurality of steering vectors is based on received orthogonal pilot transmissions;
and
means for performing spatial processing on the plurality of data symbol streams with the plurality of steering vectors, one steering vector for each data symbol stream, to obtain a plurality of transmit symbol streams for transmission from a plurality of transmit antennas, wherein the plurality of steering vectors are estimates of transmitter steering vectors required to orthogonalize the plurality of spatial channels, and
wherein the plurality of data symbol streams are recovered at a receiver with a spatial filter having a response derived based on a minimum mean square error (MMSE) criterion that minimizes mean square error between a plurality of filtered symbol streams from the spatial filter and the plurality of data symbol streams,
W={circumflex over (V)}HĤH[Ĥ{circumflex over (V)}{circumflex over (V)}HĤH+ønn]-1,
where W is the spatial filter response,
{circumflex over (V)} is a matrix of the steering vectors used for spatial processing at the transmitter,
Ĥ is the estimated channel response matrix,
{circumflex over (V)}H and ĤH denote the Hermitian or conjugate transpose of {circumflex over (V)} and Ĥ respectively, and
ønn is an autocovariance matrix of noise at the receiver.

8 more elements

Dependencies are inferred from the claim text.

Receiver spatial processing for eigenmode transmission in a MIMO system

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Receiver spatial processing for eigenmode transmission in a MIMO system

Life of this patent

Abstract

Claims31