Uplink transmission presence detection

1. A method performed by a wireless device, the method comprising:

transmitting an uplink transmission to a radio network node;

transmitting uplink transmission presence signaling that indicates, or is usable to detect, the presence of the uplink transmission within a transmission occasion according to a configured uplink grant, wherein the uplink transmission presence signaling comprises a demodulation reference signal; and

transmitting, to the radio network node, control signaling that indicates or requests a change in a configuration with which the wireless device is to transmit the uplink transmission presence signaling in or in association with the next transmission occasion corresponding to the configured uplink grant; and

wherein the control signaling indicates or requests a change in a density in time and/or frequency of the uplink transmission presence signaling and/or a change in a power of the uplink transmission presence signaling.

2. The method of claim 1 , further comprising monitoring for feedback from the radio network node indicating that no uplink transmission presence signaling was detected, and determining whether or not to re-transmit the uplink transmission based at least in part on said monitoring.

3. The method of claim 1 , wherein possible configurations with which the uplink transmission presence signaling is transmittable include two or more different configurations of the demodulation reference signal.

4. The method of claim 3 , wherein the two or more different configurations of the demodulation reference signal configure the demodulation reference signal to be transmitted with different densities in time and/or frequency.

5. The method of claim 1 , wherein the control signaling explicitly indicates that the radio network node failed to detect the uplink transmission presence signaling that the wireless device transmitted to the radio network node, and implicitly indicates or implicitly requests the change in the configuration with which the wireless device transmits the uplink transmission presence signaling.

6. The method of claim 1 , further comprising, after transmitting the control signaling, receiving, from the radio network node, downlink control signaling that indicates:

whether or not the radio network node acknowledges or approves of the wireless device transmitting the uplink transmission presence signaling with the configuration indicated or requested by the control signaling; or

the same or a different configuration, from among multiple possible configurations, with which the wireless device is to transmit the uplink transmission presence signaling.

7. The method of claim 1 , wherein the control signaling indicates or requests a change in the density in time and/or frequency of the uplink transmission presence signaling.

8. The method of claim 1 , wherein the control signaling indicates or requests a change in the power of the uplink transmission presence signaling.

9. A method performed by a radio network node, the method comprising:

monitoring for uplink transmission presence signaling that indicates, or is usable to detect, the presence of an uplink transmission from the wireless device within a transmission occasion according to a configured uplink grant, wherein the uplink transmission presence signaling comprises a demodulation reference signal; and

receiving, from a wireless device, control signaling that indicates or requests a change in a configuration with which the wireless device is to transmit the uplink transmission presence signaling in or in association with the next transmission occasion corresponding to the configured uplink grant; and

wherein the control signaling indicates or requests a change in a density in time and/or frequency of the uplink transmission presence signaling and/or a change in a power of the uplink transmission presence signaling.

10. The method of claim 9 , further comprising, responsive to receiving the control signaling, transmitting, to the wireless device, downlink control signaling that indicates:

whether or not the radio network node acknowledges or approves of the wireless device transmitting the uplink transmission presence signaling with the configuration indicated or requested by the control signaling; or

the same or a different configuration, from among multiple possible configurations, with which the wireless device is to transmit the uplink transmission presence signaling.

11. The method of claim 10 , wherein said monitoring comprises monitoring for the uplink transmission presence signaling with the configuration indicated by the downlink control signaling.

12. The method of claim 9 , further comprising transmitting feedback from the radio network node to the wireless device indicating that no uplink transmission presence signaling was detected according to said monitoring.

13. The method of claim 9 , wherein the uplink transmission presence signaling indicates, or is usable to detect, the presence of the uplink transmission within a resource allocation allocated to the wireless device and/or within a transmission occasion according to a configured uplink grant.

14. The method of claim 9 , wherein the control signaling explicitly indicates that the radio network node failed to detect the uplink transmission presence signaling that the wireless device transmitted to the radio network node, and implicitly indicates or implicitly requests the change in the configuration with which the wireless device transmits the uplink transmission presence signaling.

15. A wireless device comprising:

communication circuitry; and

processing circuitry configured to:

transmit an uplink transmission to a radio network node;

transmit uplink transmission presence signaling that indicates, or is usable to detect, the presence of the uplink transmission within a transmission occasion according to a configured uplink grant, wherein the uplink transmission presence signaling comprises a demodulation reference signal; and

transmit, to the radio network node, control signaling that indicates or requests a change in a configuration with which the wireless device is to transmit the uplink transmission presence signaling in or in association with the next transmission occasion corresponding to the configured uplink grant; and

wherein the control signaling indicates or requests a change in a density in time and/or frequency of the uplink transmission presence signaling and/or a change in a power of the uplink transmission presence signaling.

16. The wireless device of claim 15 , wherein the processing circuitry is further configured to monitor for feedback from the radio network node indicating that no uplink transmission presence signaling was detected, and determine whether or not to re-transmit the uplink transmission based at least in part on monitoring for the feedback.

17. The wireless device of claim 15 , wherein the control signaling indicates or requests a change in the density in time and/or frequency of the uplink transmission presence signaling.

18. The wireless device of claim 15 , wherein the control signaling indicates or requests a change in the power of the uplink transmission presence signaling.

19. A radio network node comprising:

communication circuitry; and

processing circuitry configured to:

monitor for uplink transmission presence signaling that indicates, or is usable to detect, the presence of an uplink transmission from the wireless device within a transmission occasion according to a configured uplink grant, wherein the uplink transmission presence signaling comprises a demodulation reference signal;

receive, from a wireless device, control signaling that indicates or requests a change in a configuration with which the wireless device is to transmit the uplink transmission presence signaling in or in association with the next transmission occasion corresponding to the configured uplink grant; and

wherein the control signaling indicates or requests a change in a density in time and/or frequency of the uplink transmission presence signaling and/or a change in a power of the uplink transmission presence signaling.

20. The radio network node of claim 19 , wherein the processing circuitry is further configured to, responsive to receiving the control signaling, transmit, to the wireless device, downlink control signaling that indicates:

whether or not the radio network node acknowledges or approves of the wireless device transmitting the uplink transmission presence signaling with the configuration indicated or requested by the control signaling; or

the same or a different configuration, from among multiple possible configurations, with which the wireless device is to transmit the uplink transmission presence signaling.