Methods and devices for moving from first cell to second cell
Methods and systems are described for assisting a user equipment in moving from a first cell to a second cell in a telecommunications system. Embodiments include triggering the sending of ephemeris data, or other data, in a neighboring cell into which a user equipment is moving. The user equipment can send, while in a first cell, a request for triggering broadcast of data in the neighboring cell, according to configuration information. The user equipment can then enter the neighboring cell and receive the data.
1 . A method performed by a user equipment (UE), for moving from a first cell to a second cell, wherein the first cell is a serving cell of the UE, and the second cell comprises one of one or more neighbor cells, the method comprising:
transmitting to a base station associated with the first cell, while being served in the first cell, a request for triggering a broadcast of information data in the second cell according to configuration information prior to moving from the first cell to the second cell;
receiving the information data broadcast by a second base station associated with the second cell; and
calculating, by using the received information data, at least one of time and frequency pre-compensation to be applied to an uplink transmission in the second cell.
2 . The method of claim 1 , further comprising obtaining, from the base station associated with the first cell, the configuration information for the request for the broadcast of the information data in one or more neighbor cells.
3 . The method of claim 1 , wherein the transmitting a request comprises at least one of:
transmitting the request prior to performing cell reselection to the second cell; or
transmitting the request prior to executing a handover to the second cell.
4 . The method of claim 1 , further comprising:
receiving a response message confirming or rejecting the request; and
if the response message confirming the request is received, monitoring the information data from the downlink transmissions in the second cell.
5 . The method of claim 1 , wherein the information data comprises satellite ephemeris data broadcast via system information.
6 . The method of claim 2 , wherein the request for the broadcast of the information data in one or more neighbor cells comprises at least one of: a system information request, an ephemeris data request using a random-access preamble or a message related to a random-access procedure, a random access Msg3, a 2-step random access MsgA, and a dedicated RRC message request.
7 . The method of claim 6 , wherein the system information request includes at least one of:
an Msg1 based system information request for triggering broadcast of information data in the second cell;
an Msg3 based request for triggering broadcast of information data in the second cell; and
a 2-step random access-based request for triggering broadcast of information data in the second cell.
8 . A method performed by a first network node, for moving a user equipment (UE) from a first cell associated with the first network node to a second cell, wherein the first cell is a serving cell for the UE, the method comprising:
receiving from the UE, in the first cell, a request for triggering broadcast of information data in the second cell;
determining whether the second cell is served by the first network node or a second network node; and
if the second cell is served by the second network node, forwarding the request for broadcast of the information data to the second network node; and if the second cell is served by the first network node, broadcasting, by the first network node, the requested information data in the second cell.
9 . The method of claim 8 , further comprising at least one of:
obtaining configuration information related to an approach for the UE to request broadcast of the information data in one or more neighbor cells; and
configuring the UE, using broadcast system information in the first cell, with the information related to the approach for request of broadcast of the information data in the one or more neighbor cells.
10 . The method of claim 8 , wherein receiving a request comprises at least one of:
receiving the request prior to the UE performing cell reselection to the second cell; and
receiving the request prior to the UE executing a handover to the second cell.
11 . The method of claim 8 , further comprising determining, if the second cell is served by the first network node, determining whether to accept the request to broadcast the information data in the second cell.
12 . The method of claim 8 , further comprising receiving from the second network node, if the second cell is served by the second network node, a response message confirming or rejecting the request to broadcast the information data in the second cell.
13 . The method of claim 11 , further comprising transmitting, to the UE, a response message confirming or rejecting the request to broadcast the information data in the second cell.
14 . The method of claim 8 , wherein broadcasting the requested information data in the second cell comprises broadcasting one or more of:
after a delay;
at a designated time;
one or more times within a time interval; or
a number of repetitions;
according to configuration information or the request from the UE.
15 . A second network node of a non-terrestrial network comprising:
a processor; and
a memory having stored thereon a computer program which, when executed on the processor, causes the processor to carry out a method for moving a user equipment (UE) from a first cell to a second cell associated with the second network node, wherein the first cell is a serving cell of the UE and is controlled by a first network node, wherein the second cell comprises one of one or more neighbor cells of the first cell, the method comprising:
receiving, from the first network node, a request for triggering broadcast information data in the second cell, wherein the information data comprises satellite ephemeris data broadcast via system information, and wherein the satellite ephemeris data comprises:
orbital, position and velocity information of a satellite, and
information about inter-node propagation path, wherein the information about inter-node propagation path comprises feeder link propagation delay and feeder link Doppler shift, where the feeder link is the communication link between the satellite and a gateway of the non-terrestrial network.
16 . The second network node of claim 15 , the method further comprising broadcasting the requested information data in the second cell.
17 . The second network node of claim 15 , the method further comprising determining whether to accept the request to broadcast the information data in the second cell.
18 . The second network node of claim 15 , the method further comprising transmitting, to the first network node, a response message confirming or rejecting the request to broadcast the information data in the second cell.