PERFORMING RANDOM ACCESS PROCEDURE FOR LAYER 1 /LAYER 2-TRIGGERED MOBILITY IN WIRELESS NETWORKS
A method for performing an RA procedure for LTM is provided. The method receives a PDCCH order for initiating the RA procedure for an LTM candidate cell. The PDCCH order indicates that an index of a preamble is not “0.” The PDCCH order includes a first DCI field indicating that a transmission of the preamble is an initial transmission or a re-transmission and a second DCI field indicating the LTM candidate cell. The method increments a power ramping counter by 1 when the first DCI field indicates the re-transmission and the PDCCH order indicates an SSB for the re-transmission of the preamble. The SSB is the same as an SSB used in a previous transmission of the preamble. The method sets, based on the incremented power ramping counter, a power parameter. The method re-transmits, to the LTM candidate cell, the preamble based on at least the set power parameter.
1 . A method for performing, by a user equipment (UE), a random access (RA) procedure for layer 1 (L1)/layer 2 (L2)-triggered mobility (LTM), the method comprising:
receiving, from a source cell, a plurality of candidate cell configurations;
receiving, from the source cell, a physical downlink control channel (PDCCH) order for initiating the RA procedure for an LTM candidate cell, the PDCCH order indicating that an index of a preamble for the RA procedure is not “0” and comprising a first downlink control information (DCI) field indicating that a transmission of the preamble is an initial transmission or a re-transmission and a second DCI field indicating the LTM candidate cell;
incrementing a power ramping counter by 1 in a case that the first DCI field indicates that the transmission of the preamble is the re-transmission and the PDCCH order further indicates a synchronization signal block (SSB) for the re-transmission of the preamble for the LTM candidate cell, the SSB being the same as an SSB that was used in a previous transmission of the preamble for the LTM candidate cell;
setting, based on the incremented power ramping counter, a power parameter for the re-transmission of the preamble; and
re-transmitting, to the LTM candidate cell, the preamble based on the set power parameter and a physical random access channel (PRACH) resource configured by a candidate cell configuration of the plurality of candidate cell configurations, wherein the candidate cell configuration is associated with the LTM candidate cell.
2 . The method of claim 1 , wherein the second DCI field indicates the LTM candidate cell by indicating an index of the candidate cell configuration associated with the LTM candidate cell.
3 . The method of claim 1 , wherein:
the first DCI field includes a bit to indicate that the transmission of the preamble is the initial transmission or the re-transmission,
in a case that the bit is “0”, the bit indicates that the transmission of the preamble is the initial transmission, and
in a case that the bit is “1”, the bit indicates that the transmission of the preamble is the re-transmission.
4 . A user equipment (UE) for performing a random access (RA) procedure for layer 1 (L1)/layer 2 (L2)-triggered mobility (LTM), the UE comprising:
at least one processor; and
at least one non-transitory computer-readable medium coupled to the at least one processor, and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the UE to:
receive, from a source cell, a plurality of candidate cell configurations;
receive, from the source cell, a physical downlink control channel (PDCCH) order for initiating the RA procedure for an LTM candidate cell, the PDCCH order indicating that an index of a preamble for the RA procedure is not “0” and comprising a first downlink control information (DCI) field indicating that a transmission of the preamble is an initial transmission or a re-transmission and a second DCI field indicating the LTM candidate cell;
increment a power ramping counter by 1 in a case that the first DCI field indicates that the transmission of the preamble is the re-transmission and the PDCCH order further indicates a synchronization signal block (SSB) for the re-transmission of the preamble for the LTM candidate cell, the SSB being the same as an SSB that was used in a previous transmission of the preamble for the LTM candidate cell;
set, based on the incremented power ramping counter, a power parameter for the re-transmission of the preamble; and
re-transmit, to the LTM candidate cell, the preamble based on the set power parameter and a physical random access channel (PRACH) resource configured by a candidate cell configuration of the plurality of candidate cell configurations, wherein the candidate cell configuration is associated with the LTM candidate cell.
5 . The UE of claim 4 , wherein the second DCI field indicates the LTM candidate cell by indicating an index of the candidate cell configuration associated with the LTM candidate cell.
6 . The UE of claim 4 , wherein:
the first DCI field includes a bit to indicate that the transmission of the preamble is the initial transmission or the re-transmission,
in a case that the bit is “0”, the bit indicates that the transmission of the preamble is the initial transmission, and
in a case that the bit is “1”, the bit indicates that the transmission of the preamble is the re-transmission.
7 . A method for performing, by a base station, a random access (RA) procedure for layer 1 (L1)/layer 2 (L2)-triggered mobility (LTM), the method comprising:
transmitting, to a user equipment (UE), a plurality of candidate cell configurations;
transmitting, to the UE, a physical downlink control channel (PDCCH) order for initiating the RA procedure for an LTM candidate cell, the PDCCH order indicating that an index of a preamble for the RA procedure is not “0” and comprising a first downlink control information (DCI) field indicating that a transmission of the preamble is an initial transmission or a re-transmission and a second DCI field indicating the LTM candidate cell; and
receiving, from the UE, the preamble based on a physical random access channel (PRACH) resource configured by a candidate cell configuration of the plurality of candidate cell configurations, wherein the candidate cell configuration is associated with the LTM candidate cell.
8 . The method of claim 7 , wherein the second DCI field indicates the LTM candidate cell by indicating an index of the candidate cell configuration associated with the LTM candidate cell.
9 . The method of claim 7 , wherein:
the first DCI field includes a bit to indicate that the transmission of the preamble is the initial transmission or the re-transmission,
in a case that the bit is “0”, the bit indicates that the transmission of the preamble is the initial transmission, and
in a case that the bit is “1”, the bit indicates that the transmission of the preamble is the re-transmission.
10 . The method of claim 7 , wherein:
the first DCI field indicates that the transmission of the preamble is the re-transmission, and
the PDCCH order further indicates a synchronization signal block (SSB) for the re-transmission of the preamble for the LTM candidate cell, the SSB being the same as an SSB that was used in a previous transmission of the preamble for the LTM candidate cell.