System and method for uplink and downlink in multi-point communications
A user equipment (UE) may receive first configuration information of a carrier of a serving cell, including a first association of a first group of uplink (UL) signals or channels on the carrier in the serving cell with a first UL timing advance group (TAG) of the UE, and second configuration information of the carrier including a second association of a second group of UL signals or channels on the carrier with a second UL TAG of the UE. The UE may transmit a UL signal/channel in the first group of UL signals or channels according to a TA value of the first UL TAG, and transmit a UL signal/channel in the second group of UL signals or channels according to a TA value of the second UL TAG.
1 . A method, comprising:
receiving, by a user equipment (UE), first configuration information and second configuration information of a serving cell, the first configuration information indicating a first timing advance group (TAG) ID of the serving cell, the second configuration information indicating a second TAG ID of the serving cell;
transmitting, by the UE, a first uplink (UL) transmission at a first transmission start time on a UL bandwidth part (BWP) of the serving cell according to a first timing advance (TA) offset value of a first TAG identified by the first TAG ID and according to a first downlink (DL) reference signal (RS) timing, the first transmission start time equaling a first start time corresponding to the first DL RS timing minus a first time offset, the first time offset based on the first TA offset value; and
transmitting, by the UE, a second UL transmission at a second transmission start time on the UL BWP of the serving cell according to a second TA offset value of a second TAG identified by the second TAG ID and according to a second DL RS timing, the second transmission start time equaling a second start time corresponding to the second DL RS timing minus a second time offset, the second time offset based on the second TA offset value.
2 . The method of claim 1 , wherein the first configuration information indicates a first association between the first UL transmission, a first DL RS received by the UE, and the first TAG ID, and wherein the second configuration information indicates a second association between the second UL transmission, a second DL RS received by the UE, and the second TAG ID.
3 . The method of claim 1 , wherein the first DL RS timing is a first time of a first path of a first DL RS received by the UE, and the second DL RS timing is a second time of a second path of a second DL RS received by the UE.
4 . The method of claim 1 , wherein a first DL RS for the first DL RS timing is a synchronization signal block (SSB) or is a channel state information RS (CSI-RS) quasi-co-located (QCLed) with the SSB transmitted on a carrier of the serving cell, and a first physical cell identity (PCI) of the SSB is the same as a PCI of the serving cell.
5 . The method of claim 4 , wherein a second DL RS for the second DL RS timing is an additional SSB configured for the serving cell or is an additional CSI-RS QCLed with the additional SSB configured for the serving cell, and the additional SSB is transmitted on the carrier of the serving cell.
6 . The method of claim 5 , wherein a second PCI of the additional SSB is different from a PCI of any serving cell configured for the UE on any carrier.
7 . The method of claim 1 , wherein a first DL RS for the first DL RS timing is associated with a first control resource set (CORESET) pool index, and a second DL RS for the second DL RS timing is associated with a second CORESET pool index.
8 . The method of claim 1 ,
wherein the first UL transmission is associated with a first DL RS for the first DL RS timing via a first transmission configuration indication (TCI) state, and
wherein the second UL transmission is associated with a second DL RS for the second DL RS timing via a second TCI state.
9 . The method of claim 8 , further comprising:
receiving, by the UE, a first association message and a second association message,
the first association message associating the first DL RS with the first TAG ID,
the second association message associating the second DL RS with the second TAG ID.
10 . The method of claim 9 ,
the first association message including a first cell ID of the serving cell,
the second association message including a second cell ID different from the first cell ID of the serving cell.
11 . The method of claim 8 ,
wherein the first TCI state and the second TCI state indicate at least one of a quasi-co-location (QCL) relationship and a pathloss RS relationship between a UL transmission and a DL RS.
12 . The method of claim 1 ,
wherein a difference between the first DL RS timing and the second DL RS timing is larger than a cyclic prefix (CP) length of the UL BWP.
13 . The method of claim 1 ,
wherein the first UL transmission and the second UL transmission are configured for the UL BWP.
14 . The method of claim 1 ,
wherein a first DL RS for the first DL RS timing and a second DL RS for the second DL RS timing are configured for the UL BWP.
15 . A user equipment (UE), comprising:
at least one processor; and
a non-transitory computer readable storage medium storing programming, the programming including instructions that, when executed by the at least one processor, cause the UE to perform operations including:
receiving first configuration information and second configuration information of a serving cell, the first configuration information indicating a first timing advance group (TAG) ID of the serving cell, the second configuration information indicating a second TAG ID of the serving cell;
transmitting a first uplink (UL) transmission at a first transmission start time on a UL bandwidth part (BWP) of the serving cell according to a first timing advance (TA) offset value of a first TAG identified by the first TAG ID and according to a first downlink (DL) reference signal (RS) timing, the first transmission start time equaling a first start time corresponding to the first DL RS timing minus a first time offset, the first time offset based on the first TA offset value; and
transmitting a second UL transmission at a second transmission start time on the UL BWP of the serving cell according to a second TA offset value of a second TAG identified by the second TAG ID and according to a second DL RS timing, the second transmission start time equaling a second start time corresponding to the second DL RS timing minus a second time offset, the second time offset based on the second TA offset value.
16 . The UE of claim 15 , wherein the first configuration information indicates a first association between the first UL transmission, a first DL RS received by the UE, and the first TAG ID, and wherein the second configuration information indicates a second association between the second UL transmission, a second DL RS received by the UE, and the second TAG ID.
17 . The UE of claim 16 , wherein the first DL RS timing is a first time of a first path of the first DL RS received by the UE, and the second DL RS timing is a second time of a second path of the second DL RS received by the UE.
18 . The UE of claim 15 , wherein a first DL RS for the first DL RS timing is a synchronization signal block (SSB) or is a channel state information RS (CSI-RS) quasi-co-located (QCLed) with the SSB transmitted on a carrier of the serving cell, and a first physical cell identity (PCI) of the SSB is the same as a PCI of the serving cell.
19 . The UE of claim 18 , wherein a second DL RS for the second DL RS timing is an additional SSB configured for the serving cell or is an additional CSI-RS QCLed with the additional SSB configured for the serving cell, and the additional SSB is transmitted on the carrier of the serving cell.
20 . The UE of claim 19 , wherein a second PCI of the additional SSB is different from a PCI of any serving cell configured for the UE on any carrier.
21 . The UE of claim 15 , wherein a first DL RS for the first DL RS timing is associated with a first control resource set (CORESET) pool index, and a second DL RS for the second DL RS timing is associated with a second CORESET pool index.
22 . The UE of claim 15 ,
wherein the first UL transmission is associated with a first DL RS for the first DL RS timing via a first transmission configuration indication (TCI) state, and
wherein the second UL transmission is associated with a second DL RS for the second DL RS timing via a second TCI state.
23 . The UE of claim 22 , the operations further comprising:
receiving a first association message and a second association message,
the first association message associating the first DL RS with the first TAG ID,
the second association message associating the second DL RS with the second TAG ID.
24 . The UE of claim 22 ,
wherein the first TCI state and the second TCI state indicate at least one of a quasi-co-location (QCL) relationship and a pathloss RS relationship between a UL transmission and a DL RS.
25 . The UE of claim 15 ,
wherein a difference between the first DL RS timing and the second DL RS timing is larger than a cyclic prefix (CP) length of the UL BWP.
26 . The UE of claim 15 ,
wherein the first UL transmission and the second UL transmission are configured for the UL BWP.
27 . The UE of claim 15 ,
wherein a first DL RS for the first DL RS timing and a second DL RS for the second DL RS timing are configured for the UL BWP.
28 . A non-transitory computer-readable medium having instructions stored thereon that, when executed by a user equipment (UE), cause the UE to perform operations, the operations comprising:
receiving first configuration information and second configuration information of a serving cell, the first configuration information indicating a first timing advance group (TAG) ID of the serving cell, the second configuration information indicating a second TAG ID of the serving cell;
transmitting a first uplink (UL) transmission at a first transmission start time on a UL bandwidth part (BWP) of the serving cell according to a first timing advance (TA) offset value of a first TAG identified by the first TAG ID and according to a first downlink (DL) reference signal (RS) timing, the first transmission start time equaling a first start time corresponding to the first DL RS timing minus a first time offset, the first time offset based on the first TA offset value; and
transmitting a second UL transmission at a second transmission start time on the UL BWP of the serving cell according to a second TA offset value of a second TAG identified by the second TAG ID and according to a second DL RS timing, the second transmission start time equaling a second start time corresponding to the second DL RS timing minus a second time offset, the second time offset based on the second TA offset value.