Channel State Feedback for a Wireless Link having Phase Relaxed Channels

A method for providing channel state feedback related to a wireless link between a transmitter having multiple transmit antennas and a receiver having at least one receive antenna, wherein the method comprises:

• determining channel estimates for at least a subset of effective channels between the transmitter and the receiver, each effective channel including a propagation channel, and signal paths in the transmitter and the receiver;
• determining frequency-independent and/or inter-antenna-independent channel state information associated with phase relaxation of at least the subset of the effective channels based on the channel estimates;
• generating channel state feedback, including at least a representation of the frequency-independent and/or inter-antenna-independent channel state information associated with the phase relaxation;
• and
• transmitting the channel state feedback to the transmitter.

A method of performing multi-antenna transmission from a transmitter having multiple transmit antennas to a receiver having at least one receive antenna, wherein the method comprises:

• receiving channel state feedback, including at least a representation of frequency-independent and/or inter-antenna-independent channel state information associated with phase relaxation of at least a subset of effective channels between the transmitter and the receiver, each effective channel including a propagation channel, and signal paths in the transmitter and the receiver;
• determining a transmission operation at least partly based on the channel state feedback, including the representation of frequency-independent and/or inter-antenna-independent channel state information associated with the phase relaxation;
• and
• performing multi-antenna transmission according to the determined transmission operation.

A communication unit, comprising:

• transceiver circuitry configured for receiving multi-antenna transmissions from a transmitter via at least one receive antenna;
• and
• processing circuitry operatively associated with the transceiver circuitry and configured to:
• determine channel estimates for at least a subset of the effective channels between the transmitter and the communication unit, each effective channel including a propagation channel, and signal paths in the transmitter and a receiver portion of the communication unit;
• determine frequency-independent and/or inter-antenna-independent channel state information associated with phase relaxation of at least the subset of the effective channels based on the channel estimates;
• generate channel state feedback including at least a representation of the frequency-independent and/or inter-antenna-independent channel state information associated with the phase relaxation;
• and
• transmit the channel state feedback to the transmitter.

A communication unit comprising:

• transceiver circuitry configured for multi-antenna transmission from multiple transmit antennas to a receiver having at least one receive antenna;
• and
• processing circuitry operatively associated with the transceiver circuitry and configured to:
• receive channel state feedback, including at least a representation of frequency-independent and/or inter-antenna-independent channel state information associated with phase relaxation of at least a subset of effective channels between the communication unit and the receiver, each effective channel including a propagation channel, and signal paths in a transmitter portion of the communication unit and the receiver;
• determine a transmission operation at least partly based on the channel state feedback including the representation of frequency-independent and/or inter-antenna-independent channel state information associated with the phase relaxation;
• and
• perform multi-antenna transmission according to the determined transmission operation.