METHOD AND APPARATUS FOR PREAMBLE TRANSMISSION BASED ON THE FIRST PDCCH ORDER AND THE SECOND PDCCH ORDER IN MOBILE WIRELESS COMMUNICATION SYSTEM
A method and apparatus for layer 2 mobility is provided. Method for lower layer mobility includes transmitting the UECapabilityInformation to the base station, receiving a RRCReconfigruation from the base station, receiving a PDCCH order from the base station and transmitting a preamble to the base station based on the PDCCH order. The RRCReconfiguration includes a UE specific search space configuration information for type1 PDCCH order monitoring and a first RNTI for type1 PDCCH order monitoring and common search space identifier for type2 PDCCH order monitoring and a second RNTI for type2 PDCCH order monitoring. The RRCReconfiguration includes one or more inner RRCReconfiguration and associated mobility group identifier.
1 . A method comprising:
receiving, by a base station from a user device, capability information associated with the user device;
transmitting, to the user device, a first radio resource control (RRC) message, wherein the first RRC message comprises:
at least one configuration parameter associated with a serving cell; and
at least one configuration parameter associated with layer-1/layer-2 triggered mobility (LTM);
transmitting, to the user device, downlink control information (DCI) associated with a physical downlink control channel (PDCCH) order, wherein the DCI comprises:
a first field comprising a value associated with the PDCCH order; and
a second field configured to comprise a first value associated with the serving cell or a second value associated with a LTM candidate cell;
based on the second value being comprised in the second field, receiving, via the LTM candidate cell, a random access preamble; and
after receiving the random access preamble, transmitting a second message comprising a timing advance value associated with the LTM candidate cell.
2 . The method of claim 1 , wherein the first RRC message comprises:
search space configuration information for monitoring a PDCCH order of a first type;
search space configuration information for monitoring a PDCCH order of a second type;
a first radio network temporary identifier (RNTI) associated with the PDCCH order of the first type; and
a second RNTI associated with the PDCCH order of the second type.
3 . The method of claim 1 , wherein the first RRC message comprises a plurality of RRC reconfiguration messages, and
wherein each of the plurality of RRC reconfiguration messages comprises at least one configuration parameter associated with a respective LTM candidate cell.
4 . The method of claim 1 , wherein:
the first value comprised in the second field of the DCI corresponds to a PDCCH order, of a first type, associated with the serving cell; and
the second value comprised in the second field of the DCI corresponds to a PDCCH order, of a second type, associated with the LTM candidate cell.
5 . The method of claim 1 , wherein the first RRC message is transmitted via a first cell of a serving cell group, and
wherein the second message is transmitted via the first cell.
6 . The method of claim 5 , wherein the serving cell is the first cell.
7 . The method of claim 5 , wherein the second message is comprised in a medium access control protocol data unit (MAC PDU), and
wherein the second message comprises a medium access control (MAC) control element (CE) indicating a switching from the first cell to the LTM candidate cell.
8 . The method of claim 1 , wherein the LTM candidate cell is an SpCell of a candidate cell group.
9 . The method of claim 1 , wherein the second message comprises:
a field indicating an identity of the LTM candidate cell;
a timing advance command field indicating the timing advance value that is associated with an amount of timing adjustment; and
a synchronization signal/physical broadcast channel (SS/PBCH) index field.
10 . The method of claim 1 , wherein the DCI further comprises a random access preamble index field.
11 . The method of claim 1 , wherein the first RRC message comprises at least one configuration parameter for a candidate mobility group (CMG), wherein the CMG is a candidate cell group comprising a plurality of LTM candidate cells, and wherein the candidate cell group comprises a candidate SpCell.
12 . The method of claim 1 , wherein the at least one configuration parameter associated with LTM comprises an RRC reconfiguration (RRCReconfiguration) message for an LTM candidate cell.
13 . The method of claim 12 , wherein the RRCReconfiguration message for the LTM candidate cell comprises a medium access control (MAC) cell group configuration (MAC-CellGroupConfig) for the LTM candidate cell.
14 . The method of claim 13 , wherein the MAC-CellGroupConfig for the LTM candidate cell comprises at least one of: timing advance group configuration information for the LTM candidate cell; or at least one discontinuous reception (DRX) configuration (DRX-Config) for the LTM candidate cell.
15 . The method of claim 1 , wherein the capability information comprises at least one parameter indicating the user device supports LTM.
16 . The method of claim 1 , wherein the first RRC message is an RRC reconfiguration (RRCReconfiguration) message comprising at least one inner RRCReconfiguration message.
17 . The method of claim 1 , wherein the second field of the DCI indicates an identifier of the LTM candidate cell.
18 . The method of claim 1 , wherein the first field of the DCI is a frequency domain resource assignment field.
19 . The method of claim 1 , further comprising:
determining a subcarrier spacing (SCS) of an uplink transmission from the user device, wherein the SCS is associated with an amount of time alignment for a timing advance group (TAG), and wherein the TAG is associated with the LTM candidate cell.
20 . The method of claim 19 , wherein the uplink transmission comprises a preamble transmission.