Applying transmission compensation to transmitted signals

Abstract

The invention is mainly concerned with uplink transmission from a UE with multiple antennas and transmitters. In prior art systems, transmit precoding can be performed based on downlink channel state

Claims

1. An apparatus comprising:first transmitter circuitry for transmitting a signal;second transmitter circuitry for transmitting a signal;first receiver circuitry for receiving a signal;means for applying different transmission compensation to a signal transmitted by the first transmitter circuitry and to a signal transmitted by the second transmitter circuitry;means for calibrating the different transmission compensation comprising:means for coupling the first transmitter circuitry, within the apparatus, to the first receiver circuitry wherein a signal transmitted by the first transmitter circuitry is coupled, within the apparatus, for reception by the first receiver circuitry;means for coupling the second transmitter circuitry, within the apparatus, to the first receiver circuitry wherein a signal transmitted by the second transmitter circuitry is coupled, within the apparatus, for reception by the first receiver circuitry;using a signal transmitted by the first transmitter circuitry that is coupled, within the apparatus, to and received by the first receiver circuitry and a signal transmitted by the second transmitter circuitry that is coupled, within the apparatus, to and received by the first receiver circuitry to determine the different transmission compensation for application to a signal transmitted by the first transmitter circuitry and to a signal transmitted by the second transmitter circuitry.

2. An apparatus according to claim 1, comprising means for using precoding to apply the different transmission compensation to a signal transmitted by the first transmitter circuitry and to a signal transmitted by the second transmitter circuitry for codebook based uplink transmission or for non-codebook based uplink transmission.

3. An apparatus as claimed in claim 1 or claim 2, wherein different transmitter circuitry provide different paths to antenna ports and wherein different receiver circuitry comprise different paths from antenna ports, wherein at least some of the transmitter circuitry share a power amplifier and / or wherein at least some of the transmitter circuitry can be switched to different antenna ports.

4. An apparatus as claimed in any preceding claim, wherein different receivers have distinct different low noise amplifiers.

5. An apparatus as claimed in any preceding claim, comprising switching circuitry for selective coupling the first receiver circuitry or second receiver circuitry to at least one of the first transmitter circuitry and the second transmitter circuitry.

6. An apparatus as claimed in any preceding claim, comprising:a first transmission directional coupler for coupling the signal, transmitted by the first transmitter circuitry, out of a first transmission path leading from the first transmitter circuitry,a second transmission directional coupler for coupling the signal, transmitted by the second transmitter circuitry, out of a second transmission path leading from the second transmitter circuitry,a first reception directional coupler for coupling a signal coupled from transmitter circuitry to the first receiver circuitry,a second reception directional coupler for coupling a signal coupled from transmitter circuitry to the second receiver circuitry;a transmission-selection switching-circuitry for controlling whether a signal coupled from one or both of the first transmission directional coupler and the second transmission directional coupler is coupled to the first reception directional coupler or the second reception directional coupler.

7. An apparatus as claimed in any preceding claim, comprising:a first antenna port;a second antenna port,wherein the first transmitter circuitry is for transmitting a signal via the first antenna port, the second transmitter circuitry is for transmitting a signal via the second antenna port, the first receiver circuitry is for receiving a signal via the first antenna port; andwherein the different transmission compensation is applied to a signal transmitted by the first transmitter circuitry via the first antenna port and to a signal transmitted by the second transmitter circuitry via the second antenna port, and the means for calibrating the different transmission compensation determines the different transmission compensation for application to a signal transmitted by the first transmitter circuitry via the first antenna port and to a signal transmitted by the second transmitter circuitry via the second antenna port.

8. An apparatus as claimed in any preceding claim, comprising: second receiver circuitry for receiving a signal;third transmitter circuitry for transmitting a signal;means for applying different transmission compensation to signals transmitted by different transmitter circuitry;means for calibrating the different transmission compensation comprising:means for coupling the third transmitter circuitry, within the apparatus, to receiver circuitry wherein a signal transmitted by the third transmitter circuitry is coupled, within the apparatus, for reception by the receiver circuitry;using a signal transmitted by the third transmitter circuitry that is coupled, within the apparatus, to and received by receiver circuitry and a signal transmitted by another transmitter circuitry that is coupled, within the apparatus, to and received by the receiver circuitry to determine the different transmission compensation for application to a signal transmitted by the third transmitter circuitry and to a signal transmitted by the other transmitter circuitry.

9. An apparatus as claimed in claim 8, wherein:the means for calibrating the different transmission compensation comprises:means for coupling the third transmitter circuitry, within the apparatus, to the second receiver circuitry wherein a signal transmitted by the third transmitter circuitry is coupled, within the apparatus, for reception by the second receiver circuitry;means for coupling the second transmitter circuitry, within the apparatus, to the second receiver circuitry wherein a signal transmitted by the second transmitter circuitry is coupled, within the apparatus, for reception by the second receiver circuitry;using a signal transmitted by the second transmitter circuitry, or the first transmitter circuitry, that is coupled, within the apparatus, to and received by the second receiver circuitry, and a signal transmitted by the third transmitter circuitry that is coupled, within the apparatus, to and received by the second receiver circuitry, to determine the transmission compensation for application to a signal transmitted by the third transmitter circuitry.

10. An apparatus as claimed in any preceding claim, wherein the means for calibrating the different transmission compensation comprises means for:dividing a baseband symbol received at the first receiver circuitry by a baseband symbol transmitted by the first transmitter circuitry coupled to the first receiver circuitry to obtain a transfer function for the first transmitter circuitry and the first receiver circuitry;dividing a baseband symbol received at the first receiver circuitry by a baseband symbol transmitted by the second transmitter circuitry coupled to the first receiver circuitry to obtain a transfer function for the first transmitter circuitry and the second receiver circuitry;dividing one of the two transfer functions by the other transfer function.

11. An apparatus as claimed in claim 10, wherein the means for calibrating the different transmission compensation is operational during uplink transmission from the apparatus to a transmission reception point for purposes other than calibrating the different transmission compensation.

12. An apparatus as claimed in any preceding claim, comprising a first antenna for transmission and reception and a second antenna for transmission and reception, wherein the first antenna has maximum gain in a first direction and the second antenna has maximum gain in a second direction different to the first direction.

13. An apparatus as claimed in any preceding claim, in which the apparatus is a user equipment.

14. A method comprising:calibrating transmission compensation comprising:coupling, within an apparatus, of a first one of different transmitter circuitry, to a first receiver circuitry wherein a signal transmitted by the first one of the different transmitter circuitry is coupled, within the apparatus, for reception by the first receiver circuitry;coupling, within the apparatus, of a second one of the different transmitter circuitry to the first receiver circuitry wherein a signal transmitted by the second one of the different transmitter circuitry is coupled, within the apparatus, for reception by the first receiver circuitry;using a signal transmitted by the first one of the different transmitter circuitry that is coupled, within the apparatus, to and received by the first receiver circuitry and a signal transmitted by the second one of the different transmitter circuitry that is coupled, within the apparatus, to and received by the first receiver circuitry to determine transmission compensation for application to a signal transmitted by the second one of the different transmitter circuitry;andapplying the determined transmission compensation to a signal transmitted by the second one of the different transmitter circuitry.

15. A computer program that when run on one or more processors of an apparatus, causes: determining transmission compensation using a signal transmitted by a first one of different transmitter circuitry that is coupled, within the apparatus, to and received by the first receiver circuitry and a signal transmitted by the second one of the different transmitter circuitry that is coupled, within the apparatus, to and received by the first receiver circuitry to determine transmission compensation for application to a signal transmitted by the second one of the different transmitter circuitry;andapplication of the determined transmission compensation to a signal transmitted by the second one of the different transmitter circuitry.

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