Methods for controlling re-establishment of IAB nodes
A method, system and apparatus for controlling reestablishment of integrated access and backhaul (IAB) nodes are disclosed. According to one or more embodiments, a first integrated access and backhaul (IAB) node is provided. The first IAB node includes processing circuitry configured to, responsive to receiving a radio link failure, RLF, indication from a second IAB node, consider at least the second IAB node to be at least temporarily unsuitable for camping on a cell of the second IAB node. The processing circuitry further configured to, responsive to the second IAB node being considered to be at least temporarily unsuitable for camping, cease to camp on the second IAB node for connection reestablishment.
1. A first integrated access and backhaul (IAB) node that is configurable as a child IAB node to a second IAB node, the first IAB node comprising:
processing circuitry configured to:
receive, from the second IAB node, a backhaul adaptation protocol (BAP) control message that comprises:
a radio link failure, RLF, indication indicating a RLF has been detected between the second IAB node and a parent IAB node to the second IAB node; and
an indication of a plurality of cells that are at least temporarily unsuitable for camping for connection reestablishment due to the RLF, the plurality of cells comprising:
cells provided by the second IAB node; and
cells provided by a third IAB node that is a child IAB node to the second IAB node;
responsive to the BAP control message, prevent the first IAB node from camping on any of the plurality of cells for connection reestablishment.
2. The first IAB node of claim 1 , wherein the processing circuitry is further configured to:
responsive to receiving the RLF indication from the second IAB node, determine at least one child IAB node to the second IAB node to be unsuitable for camping for connection reestablishment.
3. The first IAB node of claim 1 , wherein the RLF indication is received in a backhaul adaptation protocol, BAP, control protocol data unit, PDU.
4. The first IAB node of claim 1 , wherein the RLF indication includes cell identifiers of a plurality of IAB nodes, each respective cell identifier of the plurality of identifiers being one of:
unsuitable for camping for connection reestablishment; and
suitable for camping for connection reestablishment.
5. A parent integrated access and backhaul (IAB) node, comprising:
processing circuitry configured to:
detect that a radio link failure, RLF, has occurred between the parent IAB node and another IAB node; and
transmit, to a first IAB node that is a child IAB node to the parent IAB node, a backhaul adaptation protocol (BAP) control message that comprises:
a RLF indication indicating the detected RLF; and
an indication of a plurality of cells that are at least temporarily unsuitable for camping for connection reestablishment due to the RLF, the plurality of cells comprising:
cells provided by the parent IAB node; and
cells provided by a third IAB node that is a child IAB node to the parent IAB node.
6. The parent IAB node of claim 5 , wherein the RLF indication is transmitted in a backhaul adaptation protocol, BAP, control protocol data unit, PDU.
7. The parent IAB node of claim 5 , wherein the RLF indication includes cell identifiers of a plurality of IAB nodes, each respective cell identifier of the plurality of identifiers being one of:
unsuitable for camping for connection reestablishment; and
suitable for camping for connection reestablishment.
8. The parent IAB node of claim 5 , wherein the RLF indication indicates a predefined timer period for which the parent IAB node is unsuitable for camping for connection reestablishment.
9. A method for a first integrated access and backhaul (IAB) node, the first IAB node being configurable as a child IAB node to a second IAB node, the method comprising:
receiving, from the second IAB node, a backhaul adaptation protocol (BAP) control message that comprises:
a radio link failure, RLF, indication indicating a RLF has been detected between the second IAB node and a parent IAB node to the second IAB node; and
an indication of a plurality of cells that are at least temporarily unsuitable for camping for connection reestablishment due to the RLF, the plurality of cells comprising:
cells provided by the second IAB node; and
cells provided by a third IAB node that is a child IAB node to is the second IAB node;
responsive to the BAP control message, prevent the first IAB node from camping on any of the plurality of cells for connection reestablishment.
10. The method of claim 9 , further comprising, responsive to receiving the RLF indication from the second IAB node, determining at least one child IAB node to the second IAB node to be unsuitable for camping for connection reestablishment.
11. The method of claim 9 , wherein the RLF indication is received in a backhaul adaptation protocol, BAP, control protocol data unit, PDU.
12. The method of claim 9 , wherein the RLF indication includes cell identifiers of a plurality of IAB nodes, each respective cell identifier of the plurality of identifiers being one of:
unsuitable for camping for connection reestablishment; and
suitable for camping for connection reestablishment.
13. The method of claim 9 , wherein at least the second IAB node is determined to be unsuitable for camping for a predefined time period.
14. The method of claim 9 , further comprising:
responsive to receiving the RLF indication from the second IAB node, changing system information to indicate at least one cell associated with the first IAB node is unsuitable for camping for connection reestablishment; and
broadcasting the changed system information.
15. The method of claim 9 , further comprising:
responsive to receiving the RLF indication from the second IAB node, broadcasting system information that indicates cells associated with the second IAB node are unsuitable for camping for connection reestablishment.
16. A method for parent integrated access and backhaul (IAB) node, the method comprising:
detecting that a radio link failure, RLF, has occurred between the parent IAB node and another IAB node; and
transmitting, to a first IAB node that is a child IAB node to the parent IAB node, a backhaul adaptation protocol (BAP) control message that comprises:
an RLF indication indicating the detected RLF; and
an indication of a plurality of cells that are at least temporarily unsuitable for camping for connection reestablishment due to the RLF, the plurality of cells comprising:
cells provided by the parent IAB node; and
cells provided by a third IAB node that is a child IAB node to the parent IAB node.
17. The method of claim 16 , wherein the RLF indication is transmitted in a backhaul adaptation protocol, BAP, control protocol data unit, PDU.
18. The method of claim 16 , wherein the RLF indication includes cell identifiers of a plurality of IAB nodes, each respective cell identifier of the plurality of identifiers being one of:
unsuitable for camping for connection reestablishment; and
suitable for camping for connection reestablishment.
19. The method of claim 16 , wherein the RLF indication indicates a predefined timer period for which the parent IAB node is unsuitable for camping for connection reestablishment.