Indication of downlink clear channel assessment failures

1. A method performed by a wireless device for detecting a downlink radio failure, the method comprising:

establishing a wireless connection with a network node using unlicensed radio spectrum;

receiving an indication that the network node incurred a clear channel assessment (CCA) failure in a prior attempt to communicate with the wireless device, wherein the indication of the CCA failure comprises a ratio of CCA failures to successful transmissions by the network node to the wireless device; and

in response to the indication of the CCA failure, determining whether to trigger a radio failure condition.

2. A wireless device operable to detect a downlink radio failure, the wireless device comprising processing circuitry operable to:

establish a wireless connection with a network node using unlicensed radio spectrum;

receive an indication that the network node incurred a clear channel assessment (CCA) failure in a prior attempt to communicate with the wireless device, wherein the indication of the CCA failure comprises a ratio of CCA failures to successful transmissions by the network node to the wireless device; and

in response to the indication of the CCA failure, determine whether to trigger a radio failure condition.

3. The wireless device of claim 2 , wherein the indication of the CCA failure is received via a physical broadcast channel (PBCH).

4. The wireless device of claim 3 , wherein the indication of the CCA failure is received outside of the master information block (MIB) of the PBCH.

5. The wireless device of claim 2 , wherein the indication of the CCA failure is received via a system information block (SIB).

6. The wireless device of claim 2 , wherein the indication of the CCA failure is received via a group common physical downlink control channel (GC-PDCCH).

7. The wireless device of claim 2 , wherein the indication of the CCA failure is received together with at least one of downlink control information (DCI), medium access control (MAC) control element (CE), and radio resource control (RRC) signaling.

8. The wireless device of claim 2 , wherein the indication of the CCA failure comprises a single bit and indicates whether one more CCA failures occurred.

9. The wireless device of claim 2 , wherein the indication of the CCA failure comprises more than a single bit and indicates an amount of CCA failures that occurred.

10. The wireless device of claim 2 , wherein the indication of the CCA failure comprises an indication of an availability of channels or carriers.

11. The wireless device of claim 2 , wherein the indication of the CCA failure is related to one or more beams.

12. The wireless device of claim 2 , wherein the indication of the CCA failure is related to one or more beams that correspond to a beam on which the wireless device received the indication of the CCA failure.

13. The wireless device of claim 2 , wherein the network node incurred the CCA failure when attempting to transmit a reference signal to the wireless device.

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

determining a clear channel assessment (CCA) failure occurred when attempting to communicate with a wireless device using unlicensed radio spectrum;

determining the network node is able to communicate with the wireless device using the unlicensed radio spectrum; and

transmitting, to the wireless device, an indication that the network node incurred the CCA failure in a prior attempt to communicate with the wireless device, wherein the indication of the CCA failure comprises a ratio of CCA failures to successful transmissions by the network node to the wireless device.

15. A network node comprising processing circuitry operable to:

determine a clear channel assessment (CCA) failure occurred when attempting to communicate with a wireless device using unlicensed radio spectrum;

determine the network node is able to communicate with the wireless device using the unlicensed radio spectrum; and

transmit, to the wireless device, an indication that the network node incurred the CCA failure in a prior attempt to communicate with the wireless device, wherein the indication of the CCA failure comprises a ratio of CCA failures to successful transmissions by the network node to the wireless device.

16. The network node of claim 15 , wherein the indication of the CCA failure is transmitted via a physical broadcast channel (PBCH).

17. The network node of claim 16 , wherein the indication of the CCA failure is transmitted outside of the master information block (MIB) of the PBCH.

18. The network node of claim 15 , wherein the indication of the CCA failure is transmitted via a system information block (SIB).

19. The network node of claim 15 , wherein the indication of the CCA failure is transmitted via a group common physical downlink control channel (GC-PDCCH).

20. The network node of claim 15 , wherein the indication of the CCA failure is transmitted together with at least one of downlink control information (DCI), medium access control (MAC) control element (CE), and radio resource control (RRC) signaling.

21. The network node of claim 15 , wherein the indication of the CCA failure comprises a single bit and indicates whether one more CCA failures occurred.

22. The network node of claim 15 , wherein the indication of the CCA failure comprises more than a single bit and indicates an amount of CCA failures that occurred.

23. The network node of claim 15 , wherein the indication of the CCA failure comprises an indication of an availability of channels or carriers.

24. The network node of claim 15 , wherein the indication of the CCA failure is related to one or more beams.

25. The network node of claim 15 , wherein the indication of the CCA failure is related to one or more beams that correspond to a beam on which the network node transmitted the indication of the CCA failure.

26. The network node of claim 15 , wherein the network node incurred the CCA failure when attempting to transmit a reference signal to the wireless device.