Receiver, transmitter, system and method employing space-delay precoding

A receiver, configured to receive and process a radio signal received via a frequency selective radio channel from a transmitter employing a plurality of transmit antennas,

• determine, based on the received signal, complex precoder coefficients and delays of one or more space-delay precoders for one or more transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel, and
• feed back to the transmitter the determined delays explicitly or implicitly and the determined complex precoder coefficients explicitly or implicitly, the transmitter precoding the signals to be transmitted to the receiver using the fed back delays and complex precoder coefficients,
• wherein the space-delay precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors,
• a frequency-domain codebook matrix, wherein each vector of the frequency-domain codebook matrix is associated with a delay or a delay difference, and
• a combining element per layer for complex scaling/combining one or more of the vectors selected from the spatial and/or frequency-domain codebook matrices, and
• wherein the frequency-domain codebook matrix is defined by one or more sub-matrices of a DFT matrix, wherein each sub-matrix of the DFT matrix is associated with a range of delay values or a range of delay difference values.

A transmitter, comprising:

• an antenna array having a plurality of antennas for a wireless communication with one or more receivers employing a plurality of transmission layers and the plurality of antennas;
• and
• a plurality of precoders connected to the antenna array, the precoders to apply a set of beamforming weights to one or more antennas of the antenna array to form, by the antenna array, one or more transmit beams,
• wherein the transmitter is configured to determine the beamforming weights responsive to a feedback received from a receiver, the feedback indicating delays, explicitly or implicitly, and complex precoder coefficients, explicitly or implicitly, the indicated delays and complex precoder coefficients, comprising
• complex precoder coefficients of respective frequency-domain precoders for a first subset of transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel, and
• complex precoder coefficients and delays of respective space-delay precoders for a second subset of transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel, and
• wherein the frequency-domain precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors, and
• a combining element for complex scaling/combining one or more of the spatial beamforming vectors, and
• wherein the space-delay precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors,
• a frequency-domain codebook matrix, wherein each vector of the frequency-domain codebook matrix is associated with a delay or delay difference, and
• a combining element per layer for complex scaling/combining one or more of the vectors from the spatial and/or frequency-domain codebook matrices.

A transmitter, comprising:

• an antenna array having a plurality of antennas for a wireless communication with one or more receivers;
• and
• one or more precoders connected to the antenna array, the precoder to apply a set of beamforming weights to one or more antennas of the antenna array to form, by the antenna array, one or more transmit beams,
• wherein the transmitter is configured to determine the beamforming weights responsive to a feedback received from a receiver, the feedback indicating delays, explicitly or implicitly, and complex precoder coefficients, explicitly or implicitly, of one or more space-delay precoders for one or more transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel,
• wherein the space-delay precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors,
• a frequency-domain codebook matrix, wherein each vector of the frequency-domain codebook matrix is associated with a delay or a delay difference, and
• a combining element per layer for complex scaling/combining one or more of the vectors selected from the spatial and/or frequency-domain codebook matrices, and
• wherein the frequency-domain codebook matrix is defined by one or more sub-matrices of a DFT matrix, wherein each sub-matrix of the DFT matrix is associated with a range of delay values or a range of delay difference values.

A method, comprising:

• receiving and processing a radio signal received via a frequency selective radio channel from a transmitter employing a plurality of transmission layers and transmit antennas,
• determining, based on the received signal,
• complex precoder coefficients of respective frequency-domain precoders for a first subset of transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel, and
• complex precoder coefficients and delays of respective space-delay precoders for a second subset of transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel, and
• feeding back to the transmitter the determined delays explicitly or implicitly and the determined complex precoder coefficients explicitly or implicitly, the transmitter precoding the signals to be transmitted to the receiver using the fed back delays and complex precoder coefficients,
• wherein the frequency-domain precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors, and
• a combining element for complex scaling/combining one or more of the spatial beamforming vectors, and
• wherein the space-delay precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors,
• a frequency-domain codebook matrix, wherein each vector of the frequency-domain codebook matrix is associated with a delay or delay difference, and
• a combining element per layer for complex scaling/combining one or more of the vectors from the spatial and/or frequency-domain codebook matrices.

A method for forming one or more beams for a wireless communication among a transmitter and one or more receivers, the method comprising:

• applying a set of beamforming weights to one or more antennas of an antenna array to form, by the antenna array, one or more transmit beams,
• wherein the beamforming weights are determined responsive to a feedback received from a receiver, the feedback indicating delays, explicitly or implicitly, and complex precoder coefficients, explicitly or implicitly, the indicated delays and complex precoder coefficients, comprising
• complex precoder coefficients of respective frequency-domain precoders for a first subset of transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel, and
• complex precoder coefficients and delays of respective space-delay precoders for a second subset of transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel, and
• wherein the frequency-domain precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors, and
• a combining element for complex scaling/combining one or more of the spatial beamforming vectors, and
• wherein the space-delay precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors,
• a frequency-domain codebook matrix, wherein each vector of the frequency-domain codebook matrix is associated with a delay or delay difference, and
• a combining element per layer for complex scaling/combining one or more of the vectors from the spatial and/or frequency-domain codebook matrices.

A method, comprising:

• receiving and processing a radio signal received via a frequency selective radio channel from a transmitter employing a plurality of transmit antennas,
• determining, based on the received signal, complex precoder coefficients and delays of one or more space-delay precoders for one or more transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel, and
• feeding back to the transmitter the determined delays explicitly or implicitly and the determined complex precoder coefficients explicitly or implicitly, the transmitter precoding the signals to be transmitted to the receiver using the fed back delays and complex precoder coefficients,
• wherein the space-delay precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors,
• a frequency-domain codebook matrix, wherein each vector of the frequency-domain codebook matrix is associated with a delay or a delay difference, and
• a combining element per layer for complex scaling/combining one or more of the vectors selected from the spatial and/or frequency-domain codebook matrices, and
• wherein the frequency-domain codebook matrix is defined by one or more sub-matrices of a DFT matrix, wherein each sub-matrix of the DFT matrix is associated with a range of delay values or a range of delay difference values.

A method for forming one or more beams for a wireless communication among a transmitter and one or more receivers, the method comprising:

• applying a set of beamforming weights to one or more antennas of an antenna array to form, by the antenna array, one or more transmit beams,
• wherein the beamforming weights are determined responsive to a feedback received from a receiver, the feedback indicating delays, explicitly or implicitly, and complex precoder coefficients, explicitly or implicitly, of one or more space-delay precoders for one or more transmission layers and transmit antennas at the transmitter so as to achieve a predefined property for a communication over the radio channel,
• wherein the space-delay precoder has a dual-stage structure comprising:
• a spatial codebook matrix including spatial beamforming vectors,
• a frequency-domain codebook matrix, wherein each vector of the frequency-domain codebook matrix is associated with a delay or a delay difference, and
• a combining element per layer for complex scaling/combining one or more of the vectors selected from the spatial and/or frequency-domain codebook matrices, and
• wherein the frequency-domain codebook matrix is defined by one or more sub-matrices of a DFT matrix, wherein each sub-matrix of the DFT matrix is associated with a range of delay values or a range of delay difference values.