Enhancements to CGI reporting in multi-connectivity
Embodiments include methods for a master node in a radio access network (RAN) to establish neighbor relations with a further RAN node, the master node operating in multi-connectivity towards a user equipment (UE) together with a secondary node in the RAN. Embodiments include determining that a first cell identifier associated with a cell is not included in a neighbor relations table maintained by the master node. Embodiments include sending, to the UE, a request to report a second cell identifier associated with the cell. The request includes the first cell identifier and is sent without determining whether the cell is a serving or neighbor cell for the UE. Embodiments include determining whether to establish a neighbor relation with a node associated with the first cell identifier, based on a report from the UE in response to the request. Embodiments also include complementary methods performed by a UE.
1. A method for a master node, in a radio access network (RAN), to establish a neighbor relation with a further node in the RAN, the master node operating in multi-connectivity towards a user equipment (UE) together with a secondary node in the RAN, the method comprising:
determining that a first cell identifier, associated with a cell, is not included in a neighbor relations table (NRT) maintained by the master node;
sending, to the UE, a request to report a second cell identifier associated with the cell, wherein the request includes the first cell identifier and is sent without determining whether the cell is a serving cell for the UE or a neighbor cell for the UE;
receiving the report from the UE, wherein the report includes the second cell identifier, wherein the report also includes an indication of whether the second cell identifier is associated with a serving cell for the UE or a neighbor cell for the UE; and
determining whether to establish a neighbor relation with a node associated with the first cell identifier, based on the report from the UE in response to the request,
wherein determining whether to establish the neighbor relation with the node associated with the first cell identifier comprises determining to establish neighbor relations with the further node if the report is not received within a predetermined time after sending the request.
2. The method of claim 1 , wherein the cell is provided by the secondary node or by the further node.
3. The method of claim 1 , further comprising receiving, from the UE, a measurement report including the first cell identifier, wherein the determination that the first cell identifier is not included in the NR T is made in response to the measurement report.
4. The method of claim 1 , wherein if the report includes an indication that the second cell identifier is associated with a serving cell for the UE, the report also includes an indication of whether the serving cell is a primary secondary cell (PSCell) or a secondary cell (SCell).
5. The method of claim 1 , wherein if the report includes an indication that the second cell identifier is associated with a serving cell for the UE, the report also includes one or more further cell identifiers associated with respective further serving cells of the UE.
6. The method of claim 1 , wherein determining whether the second cell identifier is associated with any node represented in the NRT comprises determining whether the second cell identifier is associated with at least one of the following: a primary secondary cell (PSCell) of the UE; and a secondary cell (SCell) of the UE.
7. The method of claim 1 , wherein the first cell identifier is a physical cell identifier (PCI) and the second cell identifier is a cell global identifier (CGI).
8. A network node, of a radio access network (RAN), configured to operate in multi-connectivity towards a user equipment (UE) together with a secondary node in the RAN and to establish a neighbor relation with a further node in the RAN, the network node comprising:
radio interface circuitry operable to communicate with the UE; and
processing circuitry operably coupled to the radio interface circuitry, whereby the processing circuitry and the radio interface circuitry are configured to perform operations corresponding to the method of claim 1 .
9. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a network node, configure the network node to perform operations corresponding to the method of claim 1 .
10. The method of claim 1 , wherein determining whether to establish a neighbor relation with the node associated with the first cell identifier comprises:
determining whether the second cell identifier is associated with any node represented in the NRT; and
based on determining that the second cell identifier is not associated with any node represented in the NRT, determining to establish a neighbor relation with the further node.
11. A method performed by a user equipment (UE) in multi-connectivity with a master node and a secondary node in a radio access network (RAN), the method comprising:
receiving, from the master node, a request to report a second cell identifier associated with a cell, wherein the request comprises a first cell identifier associated with the cell;
determining whether the cell is a serving cell for the UE or a neighbor cell for the UE;
conditionally acquiring the second cell identifier via system information broadcast by the cell, based on the determination of whether the cell is a serving cell or a neighbor cell, wherein conditionally acquiring the second cell identifier for the serving cell comprises:
based on determining that the cell is a serving cell, conditionally acquiring the second cell identifier for the serving cell based on a determination whether the second cell identifier is stored at the UE; and
based on determining that the second cell identifier is not stored at the UE, acquiring the second cell identifier via system information broadcast by the serving cell; and
sending, to the master node, a report including the second cell identifier, wherein the report also includes an indication of whether the second cell identifier is associated with a serving cell for the UE or a neighbor cell for the UE, and wherein the report is sent in response to the request regardless of whether the cell is a serving cell for the UE or a neighbor cell for the UE.
12. The method of claim 11 , wherein conditionally acquiring the second cell identifier further comprises:
based on determining that the cell is a neighbor cell, acquiring the second cell identifier for the neighbor cell via system information broadcast by the neighbor cell.
13. The method of claim 11 , wherein if the report includes an indication that the second cell identifier is associated with a serving cell for the UE, the report also includes an indication of whether the serving cell is a primary secondary cell (PSCell) or a secondary cell (SCell).
14. The method of claim 11 , wherein if the report includes an indication that the second cell identifier is associated with a serving cell for the UE, the report also includes one or more further cell identifiers associated with respective further serving cells of the UE.
15. The method of claim 11 , further comprising sending, to the master node, a measurement report including the first cell identifier, wherein the request is received in response to the measurement report.
16. The method of claim 11 , wherein the first cell identifier is a physical cell identifier (PCI) and the second cell identifier is a cell global identifier (CGI).
17. A user equipment, UE operable in multi-connectivity with a master node and a secondary node in a radio access network (RAN), the UE comprising:
radio interface circuitry configured to communicate with the master node and the secondary node; and
processing circuitry operably coupled to the radio interface circuitry, whereby the processing circuitry and the radio interface circuitry are configured to perform operations corresponding to the method of claim 11 .
18. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a user equipment, configure the user equipment to perform operations corresponding to the method of claim 11 .