Listen before talk (LBT) failure triggered scheduling request indication

1. A method, comprising:

performing, by a user equipment, listen before talk (LBT);

in response to the listen before talk (LBT) being successful, transmitting an intended transmission subsequent to the listen before talk (LBT);

in response to the listen before talk (LBT) not being successful, transmitting an indication of listen before talk (LBT) failure by transmitting a portion of the intended transmission subsequent to the listen before talk (LBT).

2. The method of claim 1 , comprising:

receiving configuration of physical uplink shared channel (PUSCH) resources from a network node;

in case of dynamic scheduling, the configuration comprises an uplink grant; and

in case of configured grant transmission, the configuration comprises configured grant (CG) physical uplink shared channel (PUSCH) configuration or activation message.

3. The method of claim 2 , wherein:

the performing comprises performing the listen before talk (LBT) prior to transmission on the physical uplink shared channel (PUSCH) resources;

in response to the listen before talk (LBT) being successful, the transmitting comprises transmitting the intended transmission on the physical uplink shared channel (PUSCH) resources;

in response to the listen before talk (LBT) not being successful, the transmitting comprises transmitting the portion of the intended transmission on the physical uplink shared channel (PUSCH) resources.

4. The method of claim 2 , wherein:

the transmitting of the indication of the listen before talk (LBT) failure comprises transmitting the indication on a first symbol of the physical uplink shared channel (PUSCH) resources.

5. The method of claim 4 , wherein:

the transmitting of the indication of the listen before talk (LBT) failure comprises transmitting a demodulation reference signal (DMRS) or transmitting a demodulation reference signal (DMRS) and uplink shared channel (UL-SCH) resource elements on the first symbol of the physical uplink shared channel (PUSCH) resources.

6. The method of claim 2 , wherein:

the transmitting of the indication of the listen before talk (LBT) failure comprises transmitting the indication on symbol after a first symbol of the physical uplink shared channel (PUSCH) resources.

7. The method of claim 6 , comprising:

performing another listen before talk (LBT) prior to transmitting the indication on a symbol after a first symbol of the physical uplink shared channel (PUSCH) resources.

8. The method of claim 6 , wherein:

the transmitting of the indication of the listen before talk (LBT) failure comprises transmitting a demodulation reference signal (DMRS) on a second or later symbol of the physical uplink shared channel (PUSCH) resources.

9. The method of claim 6 , wherein the transmitting of the indication of the listen before talk (LBT) failure comprises:

transmitting a demodulation reference signal (DMRS) on a second or later symbol of the physical uplink shared channel (PUSCH) resources, and transmitting control information in a same symbol as the demodulation reference signal or a next symbol after the demodulation reference signal,

wherein the control information comprises information about an energy level detected when measurement was performed for the listen before talk (LBT).

10. The method of claim 6 , wherein the transmitting of the indication of the listen before talk (LBT) failure comprises:

transmitting a demodulation reference signal (DMRS), wherein a symbol index for the demodulation reference signal (DMRS) indicates a detected energy level.

11. An apparatus, comprising:

at least one processor; and

at least one memory comprising computer program code,

the at least one memory and computer program code configured, with the at least one processor, to cause the apparatus at least to perform:

performing listen before talk (LBT);

in response to the listen before talk (LBT) being successful, transmitting an intended transmission subsequent to the listen before talk (LBT);

in response to the listen before talk (LBT) not being successful, transmitting an indication of listen before talk (LBT) failure by transmitting a portion of the intended transmission subsequent to the listen before talk (LBT).

12. The apparatus of claim 11 , wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to perform:

receiving a configuration of physical uplink shared channel (PUSCH) resources from a network node;

in case of dynamic scheduling, the configuration comprises an uplink grant; and

in case of configured grant transmission, the configuration comprises configured grant (CG) physical uplink shared channel (PUSCH) configuration or activation message.

13. The apparatus of claim 12 , wherein:

the performing comprises performing the listen before talk (LBT) prior to transmission on the physical uplink shared channel (PUSCH) resources;

in response to the listen before talk (LBT) being successful, the transmitting comprises transmitting the intended transmission on the physical uplink shared channel (PUSCH) resources;

in response to the listen before talk (LBT) not being successful, the transmitting comprises transmitting the portion of the intended transmission on the physical uplink shared channel (PUSCH) resources.

14. The apparatus of claim 12 , wherein:

the transmitting of the indication of the listen before talk (LBT) failure comprises transmitting the indication on a first symbol of the physical uplink shared channel (PUSCH) resources.

15. The apparatus of claim 14 , wherein:

the transmitting of the indication of the listen before talk (LBT) failure comprises transmitting a demodulation reference signal (DMRS) or transmitting a demodulation reference signal (DMRS) and uplink shared channel (UL-SCH) resource elements on the first symbol of the physical uplink shared channel (PUSCH) resources.

16. The apparatus of claim 12 , wherein:

the transmitting of the indication of the listen before talk (LBT) failure comprises transmitting the indication on symbol after a first symbol of the physical uplink shared channel (PUSCH) resources.

17. The apparatus of claim 16 , wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to:

perform another listen before talk (LBT) prior to transmitting the indication on a symbol after a first symbol of the physical uplink shared channel (PUSCH) resources.

18. The apparatus of claim 16 , wherein:

the transmitting of the indication of the listen before talk (LBT) failure comprises transmitting a demodulation reference signal (DMRS) on a second or later symbol of the physical uplink shared channel (PUSCH) resources.

19. The apparatus of claim 16 , wherein the transmitting of the indication of the listen before talk (LBT) failure comprises:

transmitting a demodulation reference signal (DMRS) on a second or later symbol of the physical uplink shared channel (PUSCH) resources, and transmitting control information in a same symbol as the demodulation reference signal or a next symbol after the demodulation reference signal,

wherein the control information comprises information about an energy level detected when measurement was performed for the listen before talk (LBT).

20. The apparatus of claim 16 , wherein the transmitting of the indication of the listen before talk (LBT) failure comprises:

transmitting a demodulation reference signal (DMRS), wherein a symbol index for the demodulation reference signal (DMRS) indicates a detected energy level.