Wireless backhaul link information via adaptation layer

1. A method comprising:

receiving, by a base station distributed unit (BS-DU), from a base station central unit (BS-CU), at least one configuration message comprising bearer configuration parameters of at least one bearer for a wireless device, wherein the at least one bearer is configured between the wireless device and the BS-CU through the BS-DU;

communicating, by the BS-DU with the wireless device and via the at least one bearer, a first adaptation layer packet, wherein a first header of the first adaptation layer packet comprises a route identifier indicating a route;

determining, by the BS-DU, a failure of a link between the BS-DU and the BS-CU; and

transmitting, by the BS-DU to the wireless device, backhaul link information indicating the failure of the link, wherein a second header of a second adaptation layer packet comprises the backhaul link information indicating the failure of the link.

2. The method of claim 1 , further comprising continuing, by the BS-DU and based on the failure of the link, reception of channel state information from the wireless device.

3. The method of claim 1 , further comprising continuing, by the BS-DU and based on the failure of the link, reception of a sounding reference signal from the wireless device.

4. The method of claim 1 , further comprising stopping, by the BS-DU and based on the failure of the link, transmission of an uplink resource grant to the wireless device.

5. The method of claim 1 , further comprising stopping, by the BS-DU and based on the failure of the link, reception of a scheduling request for the at least one bearer from the wireless device.

6. The method of claim 1 , wherein the BS-DU transmits the backhaul link information to the wireless device via at least one of:

a medium access control (MAC) control element (CE);

a physical layer command comprising downlink control information;

a radio resource control message;

an adaptive layer indication; or

an indication parameter indicating a state transition into a dormant state of one or more cells of the BS-DU.

7. The method of claim 1 , wherein the backhaul link information comprises at least one of:

a first node identifier of the BS-DU;

a second node identifier of the BS-CU;

a failure type comprising at least one of:

a temporary failure;

a failure of one of multiple backhaul links of the BS-DU; or

a failure of all backhaul links of the BS-DU;

a timer value for determining an integrated access and backhaul node failure;

an indication parameter indicating a state transition into a dormant state of one or more cells of the BS-DU;

a bearer identifier of a bearer affected by the failure; or

a cell identifier of a cell of the BS-CU, the cell causing the failure.

8. The method of claim 1 , wherein the backhaul link information comprises at least one bearer identifier of the at least one bearer that is affected by the failure.

9. The method of claim 1 , wherein the determining of the failure is based on at least one of:

a beam failure of a cell of the BS-CU;

a beam failure recovery failure of a cell of the BS-CU;

a random access failure via a cell of the BS-CU;

a time alignment timer expiration of a cell of the BS-CU;

a first number of radio link control packet retransmissions to the BS-CU;

a reference signal received power of a cell of the BS-CU; or

an expiration of a failure timer.

10. The method of claim 9 , wherein the failure timer is configured for at least one of:

the wireless device;

a packet data unit session of the wireless device;

a quality-of-service flow of the wireless device;

a bearer of the wireless device;

a logical channel of the wireless device; or

a network slice of the wireless device.

11. A base station distributed unit (BS-DU) comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the BS-DU to perform operations comprising:

receiving, from a base station central unit (BS-CU), at least one configuration message comprising bearer configuration parameters of at least one bearer for a wireless device, wherein the at least one bearer is configured between the wireless device and the BS-CU through the BS-DU;

communicating, with the wireless device and via the at least one bearer, a first adaptation layer packet, wherein a first header of the first adaptation layer packet comprises a route identifier indicating a route;

determining a failure of a link between the BS-DU and the BS-CU; and

transmitting, to the wireless device, backhaul link information indicating the failure of the link, wherein a second header of a second adaptation layer packet comprises the backhaul link information indicating the failure of the link.

12. The BS-DU of claim 11 , wherein the operations further comprise continuing, by the BS-DU and based on the failure of the link, reception of channel state information from the wireless device.

13. The BS-DU of claim 11 , wherein the operations further comprise continuing, by the BS-DU and based on the failure of the link, reception of a sounding reference signal from the wireless device.

14. The BS-DU of claim 11 , wherein the operations further comprise stopping, by the BS-DU and based on the failure of the link, transmission of an uplink resource grant to the wireless device.

15. The BS-DU of claim 11 , wherein the operations further comprise stopping, by the BS-DU and based on the failure of the link, reception of a scheduling request for the at least one bearer from the wireless device.

16. The BS-DU of claim 11 , wherein the BS-DU transmits the backhaul link information to the wireless device via at least one of:

a medium access control (MAC) control element (CE);

a physical layer command comprising downlink control information;

a radio resource control message;

an adaptive layer indication; or

an indication parameter indicating a state transition into a dormant state of one or more cells of the BS-DU.

17. The BS-DU of claim 11 , wherein the backhaul link information comprises at least one of:

a first node identifier of the BS-DU;

a second node identifier of the BS-CU;

a failure type comprising at least one of:

a temporary failure;

a failure of one of multiple backhaul links of the BS-DU; or

a failure of all backhaul links of the BS-DU;

a timer value for determining an integrated access and backhaul node failure;

an indication parameter indicating a state transition into a dormant state of one or more cells of the BS-DU;

a bearer identifier of a bearer affected by the failure; or

a cell identifier of a cell of the BS-CU, the cell causing the failure.

18. The BS-DU of claim 11 , wherein the backhaul link information comprises at least one bearer identifier of the at least one bearer that is affected by the failure.

19. The BS-DU of claim 11 , wherein the determining of the failure is based on at least one of:

a beam failure of a cell of the BS-CU;

a beam failure recovery failure of a cell of the BS-CU;

a random access failure via a cell of the BS-CU;

a time alignment timer expiration of a cell of the BS-CU;

a first number of radio link control packet retransmissions to the BS-CU;

a reference signal received power of a cell of the BS-CU; or

an expiration of a failure timer.

20. The BS-DU of claim 19 , wherein the failure timer is configured for at least one of:

the wireless device;

a packet data unit session of the wireless device;

a quality-of-service flow of the wireless device;

a bearer of the wireless device;

a logical channel of the wireless device; or

a network slice of the wireless device.