Systems and methods for linking PDCCH candidates
Systems and methods for linking Physical Downlink Control Channel (PDCCH) candidates are provided herein. In some embodiments, a method includes: receiving a configuration of a first and second Control Resource Set (CORESET) associated with a first and second Search Space (SS) set; determining that the first and second SS set are configured with a common set of parameters; activating the first and second CORESET with a first and second TCI state; linking a first PDCCH candidate in a first PDCCH monitoring occasion to a second PDCCH candidate in a second PDCCH monitoring occasion; receiving a PDCCH in the first PDCCH candidate and the PDCCH in the second PDCCH candidate; and detecting the PDCCH in the first and the second PDCCH candidates. Some embodiments might provide a simple way for linking PDCCH candidates in two SS sets to support both intra-slot and inter-slot PDCCH repetition in either TDM or FDM manner.
1 . A method performed by a wireless device for monitoring Physical Downlink Control Channel, PDCCH, in two linked Search Space, SS, sets, the method comprising:
receiving, from a wireless node, a configuration of a first Control Resource Set, CORESET, associated with a first SS set and a second CORESET associated with a second SS set, wherein the first and second SS sets are linked, and the first SS set and the second SS set are configured with a common set of parameters comprising:
a PDCCH monitoring periodicity of k s slots;
a PDCCH monitoring offset of o s slots;
a number of PDCCH candidates
M
s
(
L
)
per aggregation level L;
a duration of T_s slots;
a number of starting symbols or PDCCH monitoring occasions per slot;
a SS set type of either a Common Search Space, CSS, set or a user equipment, UE, Specific Search Space, USS, set; and
Downlink Control Information, DCI, formats to monitor;
receiving a command activating the first CORESET with a first TCI state and the second CORESET with a second TCI state;
determining, for each aggregation level, a first PDCCH candidate in the first CORESET in a first PDCCH monitoring occasion of the first SS set in a first slot and a second PDCCH candidate in the second CORESET in a second PDCCH monitoring occasion of the second SS set in a second slot, wherein the first slot and the second slot are the same;
receiving, from the wireless node, a PDCCH in the first PDCCH candidate and a repetition of the PDCCH in the second PDCCH candidate; and
detecting DCI carried by the PDCCH in the first and the second PDCCH candidates.
2 . The method of claim 1 wherein the first and the second PDCCH candidates correspond to a same CCE aggregation level and have a same PDCCH candidate index in the respective CORESETs.
3 . The method of claim 1 , wherein the first and second PDCCH monitoring occasions have a same index according to each of the first and second SS sets in the first and second slot.
4 . The method of claim 1 , wherein the first and second slots are the same slot.
5 . The method of claim 1 further comprising:
configuring the first and the second SS sets with one or more of:
a first and a second PDCCH monitoring slot offsets, O s1 and O s2 ;
a first and a second duration, T s1 and T s2 , indicating a number of consecutive slots for PDCCH monitoring; and
a first and a second PDCCH monitoring patterns or number of starting symbols within a PDCCH monitoring slot.
6 . The method of claim 1 wherein the first slot n 1 of the first SS set and the second slot n 2 of the second SS set satisfying n 1 =nK s +O s1 +i and n 2 =nK s +O s2 +i, where n is an integer and i=0, 1, . . . , min (T s1 , T s2 )−1.
7 . The method of claim 1 , wherein the first PDCCH monitoring pattern contains a set of starting symbols with symbol indices {l 1 , l 2 , . . . , l N s1 } and the second PDCCH monitoring pattern contains a set of starting symbols with symbol indices {s 1 , s 2 , . . . , s N s2 }, where N s1 and N s2 are integers.
8 . The method of claim 1 , wherein the first PDCCH monitoring occasion starts at symbol l i in the first slot of the first SS set and the second PDCCH monitoring occasion starts at symbol s i in the second slot of the second SS set, where i=1 . . . , min(N s1 , N s2 ).
9 . The method of claim 1 further comprising:
determining a time off set between reception of the PDCCH and a scheduled one of a Physical Downlink Shared Channel, PDSCH, a Physical Uplink Shared Channel, PUSCH, a Channel State Information Reference signal, CSI-RS, and a Sounding Reference Signal, SRS, wherein the time offset is determined between a symbol of the first and the second PDCCH candidates occurring last in time and the first symbol of the corresponding one of PDSCH, PUSCH, CSI-RS, and SRS.
10 . The method of claim 1 further comprising:
determining a Physical Uplink Control Channel, PUCCH, resource for carrying a hybrid Automatic Repeat Request Acknowledgement, HARQ-ACK, information associated with a scheduled PDSCH, wherein the determining a PUCCH resource comprises determining a PDCCH candidate among the first and the second PDCCH candidates associated with a SS set having a lower SS ID or with an associated CORESET having a lower CORESET ID.
11 . The method of claim 1 , wherein the PUCCH resource is determined based on the determined PDCCH candidate and the associated CORESET.
12 . The method of claim 1 further comprising:
determining a starting symbol of the PDCCH carrying a DCI format 1_2 scheduling a PDSCH with mapping type B as the starting symbol of one of the first and the second PDCCH monitoring occasions occurring later in time.
13 . The method of claim 1 , wherein the first and the second SS sets are linked via an identifier.
14 . The method of claim 1 , wherein the wireless device operates in a New Radio, NR, communications network.
15 . A method performed by a base station for transmitting Physical Downlink Control Channel, PDCCH, in two linked Search Space, SS, sets, the method comprising:
configuring, a wireless node, with a configuration of a first Control Resource Set, CORESET, associated with a first SS set and a second CORESET associated with a second SS set, wherein the first and second SS sets are linked;
configuring the first SS set and the second SS set with a common set of parameters comprising:
a PDCCH monitoring periodicity of k s slots;
a PDCCH monitoring offset of o s slots;
a duration of T_s slots;
a number of starting symbols or PDCCH monitoring occasions per slot;
a number of PDCCH candidates
M
s
(
L
)
per aggregation level L;
a SS set type of either a Common Search Space, CSS, set or a user equipment, UE, Specific Search Space, USS, set; and
Downlink Control Information, DCI, formats to monitor;
activating the first CORESET with a first TCI state and the second CORESET with a second TCI state;
determining, for each aggregation level, a first PDCCH candidate in the first CORESET in a first PDCCH monitoring occasion of the first SS set in a first slot and a second PDCCH candidate in the second CORESET in a second PDCCH monitoring occasion of the second SS set in a second slot, wherein the first slot and the second slot are the same; and
transmitting, to the wireless node, a PDCCH in the first PDCCH candidate and the same PDCCH in the second PDCCH candidate.
16 . The method of claim 15 wherein the first and the second PDCCH candidates correspond to a same CCE aggregation level and have a same PDCCH candidate index in the respective CORESETs.
17 . The method of claim 15 , wherein the first and second PDCCH monitoring occasions have a same index according to each of the first and second SS sets in the first and second slot.
18 . The method of claim 15 , wherein the first and second slots are the same slot.
19 . The method of claim 15 further comprising:
configuring the first and the second SS sets with one or more of:
a first and a second PDCCH monitoring slot offsets, O_s1 and O_s2;
a first and a second duration, T_s1 and T_s2, indicating a number of consecutive slots for PDCCH monitoring; and
a first and a second PDCCH monitoring patterns or number of starting symbols within a PDCCH monitoring slot.
20 . The method of claim 15 , wherein the first slot n 1 of the first SS set and the second slot n 2 of the second SS set satisfying n 1 =nK s +O s1 +i and n 2 =nK s +O s2 +i, where n is an integer and i=0, 1, . . . , min (T s1 , T s2 )−1.
21 . The method of claim 15 , wherein the first PDCCH monitoring pattern contains a set of starting symbols with symbol indices {l 1 , l 2 , . . . , l N s1 } and the second PDCCH monitoring pattern contains a set of starting symbols with symbol indices {s 1 , s 2 , . . . , s N s2 }, where N s1 and N s2 are integers.
22 . The method of claim 15 , wherein the first PDCCH monitoring occasion starts at symbol l i in the first slot of the first SS set and the second PDCCH monitoring occasion starts at symbol s i in the second slot of the second SS set, where i=1 . . . , min (N s1 , N s2 ).
23 . The method of claim 15 further comprising:
determining a time off set between reception of the PDCCH and a scheduled one of a Physical Downlink Shared Channel, PDSCH, a Physical Uplink Shared Channel, PUSCH, a Channel State Information Reference signal, CSI-RS, and a Sounding Reference Signal, SRS, wherein the time offset is determined between a symbol of the first and the second PDCCH candidates occurring last in time and the first symbol of the corresponding one of PDSCH, PUSCH, CSI-RS, and SRS.
24 . The method of claim 15 further comprising:
determining a Physical Uplink Control Channel, PUCCH, resource for carrying a hybrid Automatic Repeat Request Acknowledgement, HARQ-ACK, information associated with a scheduled PDSCH, wherein the determining a PUCCH resource comprises determining a PDCCH candidate among the first and the second PDCCH candidates associated with a SS set having a lower SS ID or with an associated CORESET having a lower CORESET ID.
25 . A wireless device comprising:
one or more transmitters;
one or more receivers; and
processing circuitry associated with the one or more transmitters and the one or more receivers, the processing circuitry configured to cause the wireless device to:
receive, from a wireless node, a configuration of a first Control Resource Set, CORESET, associated with a first SS set and a second CORESET associated with a second SS set, wherein the first and second SS sets are linked, and the first SS set and the second SS set are configured with a common set of parameters comprising:
a PDCCH monitoring periodicity of k s slots;
a PDCCH monitoring offset of o s slots;
a number of PDCCH candidates
M
s
(
L
)
aggregation level L;
a duration of T_s slots;
a number of starting symbols or PDCCH monitoring occasions per slot;
a SS set type of either a Common Search Space, CSS, set or a user equipment, UE, Specific Search Space, USS, set; and
Downlink Control Information, DCI, formats to monitor;
receive a command activating the first CORESET with a first TCI state and the second CORESET with a second TCI state;
determine, for each aggregation level, a first PDCCH candidate in the first CORESET in a first PDCCH monitoring occasion of the first SS set in a first slot and a second PDCCH candidate in the second CORESET in a second PDCCH monitoring occasion of the second SS set in a second slot, wherein the first slot and the second slot are the same;
receive, from the wireless node, a PDCCH in the first PDCCH candidate and a repetition of the PDCCH in the second PDCCH candidate; and
detect DCI carried by the PDCCH in the first and the second PDCCH candidates.
26 . A radio access node comprising:
one or more transmitters;
one or more receivers; and
processing circuitry associated with the one or more transmitters and the one or more receivers, the processing circuitry configured to cause the radio access node to:
configure, a wireless node, with a configuration of a first Control Resource Set, CORESET, associated with a first SS set and a second CORESET associated with a second SS set, wherein the first and second SS sets are linked;
configure the first SS set and the second SS set with a common set of parameters comprising:
a PDCCH monitoring periodicity of k s slots;
a PDCCH monitoring offset of o s slots;
a duration of T_s slots;
a number of starting symbols or PDCCH monitoring occasions per slot;
a number of PDCCH candidates
M
s
(
L
)
per aggregation level L;
a SS set type of either a Common Search Space, CSS, set or a user equipment, UE, Specific Search Space, USS, set; and
Downlink Control Information, DCI, formats to monitor;
activate the first CORESET with a first TCI state and the second CORESET with a second TCI state;
determine, for each aggregation level, a first PDCCH candidate in the first CORESET in a first PDCCH monitoring occasion of the first SS set in a first slot and a second PDCCH candidate in the second CORESET in a second PDCCH monitoring occasion of the second SS set in a second slot, wherein the first slot and the second slot are the same; and
transmit, to the wireless node, a PDCCH in the first PDCCH candidate and the same PDCCH in the second PDCCH candidate.