3GPP R18 multi-path

1 . A method for a first user equipment (UE) that has a first path to a network to add a second path to the network, comprising:

receiving, at the first UE, a first radio resource control (RRC) message from the network for addition of the second path; and

configuring, by the first UE, the second path based on the first RRC message;

wherein the first path is an indirect path of the first UE via a second UE to the network, the second path is a direct path of the first UE to the network, and the first UE and the second UE have serving cells belonging to the network, wherein configuring, by the first UE, the second path based on the first RRC message includes performing a secondary cell (SCell) addition procedure to add the serving cell of the first UE as the direct path for the first UE;

wherein the first path is a direct path of the first UE to the network, the second path is an indirect path of the first UE via a second UE to the network, and the first UE and the second UE have serving cells belonging to the network, wherein configuring, by the first UE, the second path based on the first RRC message includes performing a cell addition procedure to add the serving cell of the second UE as the indirect path for the first UE.

2 . The method of claim 1 , further comprising:

sending, by the first UE, a measurement report to the network when a measurement event happens.

3 . The method of claim 2 , wherein the measurement event happens when a reference signal received power (RSRP) of the serving cell of the second UE is greater than a first threshold and an RSRP of the serving cell of the first UE becomes greater than a second threshold.

4 . The method of claim 1 , wherein configuring, by the first UE, the second path based on the first RRC message includes:

performing a cell (re-) selection procedure to evaluate a candidate serving cell for the addition of the direct path; and

setting the candidate serving cell as a primary cell (PCell) of the first UE.

5 . The method of claim 1 , further comprising:

sending, by the first UE, a measurement report to the network when a measurement event happens.

6 . The method of claim 5 , wherein the measurement event happens when a reference signal received power (RSRP) of the serving cell of the first UE is greater than a first threshold and an RSRP of the serving cell of the second UE becomes greater than a second threshold.

7 . The method of claim 1 , wherein configuring, by the first UE, the second path based on the first RRC message includes:

performing a relay selection procedure to evaluate a candidate relay UE for the addition of the indirect path; and

setting the candidate relay UE as the second UE in the indirect path of the first UE.

8 . The method of claim 1 , wherein performing the cell addition procedure includes sending, by the first UE, a report to the network when a list of candidate relay UEs is updated that meet a criterion for the addition of the indirect path.

9 . The method of claim 8 , wherein the report is sent via a UEAssistanceInformation message or a SidelinkUEInformation message.

10 . The method of claim 9 , further comprising:

receiving a second RRC message to configure the indirect path.

11 . A method for a remote user equipment (UE) that has a first path to a network and a second path to the network, comprising:

receiving, at the first UE, a radio resource control (RRC) message from the network for removal of the second path; and

removing, by the first UE, the second path based on the RRC message;

wherein the first path is an indirect path of the first UE via a second UE to the network, the second path is a direct path of the first UE to the network, and the first UE and the second UE have serving cells belonging to the network, wherein the first UE performs a secondary cell (SCell) addition procedure to add the serving cell of the first UE as the direct path for the first UE;

wherein the first path is a direct path of the first UE to the network, the second path is an indirect path of the first UE via a second UE to the network, and the first UE and the second UE have serving cells belonging to the network, wherein the first UE performs a cell addition procedure to add the serving cell of the second UE as the indirect path for the first UE.

12 . The method of claim 11 , further comprising:

sending, by the first UE, a measurement report to the network when a measurement event happens.

13 . The method of claim 12 , wherein the measurement event happens when a reference signal received power (RSRP) of the serving cell of the second UE is greater than a first threshold and an RSRP of the serving cell of the first UE becomes lower than a second threshold.

14 . The method of claim 11 , further comprising:

sending, by the first UE, a measurement report to the network when a measurement event happens,

wherein the measurement event happens when a reference signal received power (RSRP) of the serving cell of the second UE is greater than a first threshold and an RSRP of the serving cell of the first UE becomes lower than a second threshold.

15 . An apparatus, comprising circuitry configured to perform a method for the apparatus, which has a first path to a network, to add a second path to the network and remove the second path from the network, the method including:

receiving a first radio resource control (RRC) message from the network for addition of the second path; and

configuring the second path based on the first RRC message;

wherein the first path is an indirect path of the first UE via a second UE to the network, the second path is a direct path of the first UE to the network, and the first UE and the second UE have serving cells belonging to the network, wherein configuring the second path based on the first RRC message includes performing a secondary cell (SCell) addition procedure to add the serving cell of the first UE as the direct path for the first UE;

wherein the first path is a direct path of the first UE to the network, the second path is an indirect path of the first UE via a second UE to the network, and the first UE and the second UE have serving cells belonging to the network, wherein configuring the second path based on the first RRC message includes performing a cell addition procedure to add the serving cell of the second UE as the indirect path for the first UE.

16 . The apparatus of claim 15 , wherein the method further includes;

receiving a second RRC message from the network for removal of the second path; and

removing the second path based on the second RRC message.