Communication nodes and methods therein for positioning in a wireless communications network

1. A method performed by a first communication node for determining the position of a second communication node in a wireless communications network, the method comprising

selecting, based on channel sounding feedback information received from the second communication node, a precoder for a beamformed transmission of a timing measurement message from a codebook of different precoders dedicated for use in beamformed transmissions of timing measurement messages;

transmitting the timing measurement message to the second communication node as the beamformed transmission based on the channel sounding feedback information received from the second communication node;

receiving an acknowledgement message from the second communication node for the timing measurement message in the beamformed transmission; and

determining the position of the second communication node at least partly based on a transmission time of the timing measurement message and a reception time of the acknowledgement message.

2. A first communication node for determining the position of a second communication node in a wireless communications network, the first communication node being configured to

select, based on channel sounding feedback information received from the second communication node, a precoder for a beamformed transmission of a timing measurement message from a codebook of different precoders dedicated for use in beamformed transmissions of timing measurement messages;

transmit the timing measurement message to the second communication node as the beamformed transmission based on the channel sounding feedback information received from the second communication node;

receive an acknowledgement message from the second communication node for the timing measurement message in the beamformed transmission; and

determine the position of the second communication node at least partly based on a transmission time of the timing measurement message and a reception time of the acknowledgement message.

3. The first communication node according to claim 2 , further configured to select the precoder based on information indicating a precoder in the channel sounding feedback information received from the second communication node, or based on the channel sounding feedback information received from the second communication node such that the received energy in the second communication node is maximized.

4. The first communication node according to claim 2 , further configured to, prior to transmitting the timing measurement message and in response to receiving a ranging request message from the second communication node, transmit an acknowledgement message for the ranging request message comprising channel sounding information to the second communication node, and receive channel sounding feedback information from the second communication node based on the channel sounding information in the transmitted acknowledgement message.

5. The first communication node according to claim 2 , further configured to, prior to the transmission of the timing measurement message and in response to receiving a ranging request message from the second communication node, perform at least one Non-Data Packet, NDP, channel sounding message exchange with the second communication node.

6. The first communication node according to claim 5 , further configured to perform the at least one NDP channel sounding message exchange with the second communication node for two or more precoders, transmit two or more timing measurement messages to the second communication node as beamformed transmissions based on each of the two or more precoders, and receive acknowledgement messages from the second communication node for the two or more transmitted timing measurement messages in the beamformed transmissions.

7. The first communication node according to claim 4 , further configured to repeat transmissions of the acknowledgement message or NDP channel sounding message for at least a subset of all beamforming directions.

8. The first communication node according to claim 2 , wherein the timing measurement message is a Fine Timing Measurement, FTM, frame or data packet.

9. A method performed by a second communication node for enabling positioning of the second communication node in a first communication node in a wireless communications network, the method comprising

transmitting, to the first communication node, channel sounding feedback information indicating a precoder for a beamformed transmission of a timing measurement message, the precoder from a codebook dedicated for use in beamformed transmissions of timing measurement messages;

receiving the timing measurement message from the first communication node as the beamformed transmission based on the channel sounding feedback information transmitted to the first communication node; and

transmitting an acknowledgement message to the first communication node for the timing measurement message in the beamformed transmission.

10. The method according to claim 9 , further comprising

determining the position of the first communication node ( 110 ; 121 ) at least partly based on a reception time of the timing measurement message and a transmission time of the acknowledgement message.

11. A second communication node for enabling positioning of the second communication node in a first communication node in a wireless communications network, the second communication node being configured to:

transmit, to the first communication node, channel sounding feedback information indicating a precoder for a beamformed transmission of a timing measurement message, the precoder from a codebook dedicated for use in beamformed transmissions of timing measurement messages;

receive the timing measurement message from the first communication node as the beamformed transmission based on the channel sounding feedback information transmitted to the first communication node; and

transmit an acknowledgement message to the first communication node for the timing measurement message in the beamformed transmission.

12. The second communication node according to claim 11 , further configured to determine the position of the first communication node at least partly based on a reception time of the timing measurement message and a transmission time of the acknowledgement message.

13. The second communication node according to claim 11 , further configured to, in response to transmitting a ranging request message from the second communication node, receive an acknowledgement message comprising channel sounding information from the first communication node, and transmit channel sounding feedback information to the first communication node based on the channel sounding information in the received acknowledgement message.

14. The second communication node according to claim 11 , further configured to, in response to transmitting a ranging request message to the first communication node, perform at least one Non-Data Packet, NDP, channel sounding message exchange with the first communication node.

15. The second communication node according to claim 14 , further configured to perform the at least one NDP channel sounding message exchange with the first communication node for two or more precoders, receive two or more timing measurement messages from the first communication node as beamformed transmissions based on each of the two or more precoders, and transmit acknowledgement messages to the first communication node for the two or more transmitted timing measurement messages in the beamformed transmissions.

16. The second communication node according to claim 11 , wherein the timing measurement message is a Fine Timing Measurement, FTM, frame or data packet.

17. A computer program product, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to claim 1 .