Dynamic search space set linking

1 . An apparatus comprising at least one processor, and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:

obtain information regarding a linkage of a first search space set and a second search space set, wherein the first search space set and the second search space set are different search spaces and are associated with a multi transmission reception point physical downlink control channel repetition, and the first search space is associated with a first transmission reception point and the second search space is associated with a second transmission reception point;

determine, based on the obtained information, that the first search space set and the second search space set are linked search space sets, and the linking is based on radio resource control configuration or a medium access control element;

determine, for the linked search space sets, a presence information of a transmission configuration indication, wherein the presence information indicates if the transmission configuration indication is enabled or disabled; and

based on the presence information, determine a field size of the transmission configuration indication in a downlink control information for the multiple transmission reception point physical downlink control channel repetition,

wherein the apparatus is further caused to receive, from a network node, an indication indicating a validity of the linkage.

2 . The apparatus according to claim 1 , wherein the presence information is determined based on a pre-determined rule or a pre-determined default value.

3 . The apparatus according to claim 1 , wherein the first search space set is associated with a first control resource set and the second search space set is associated with a second control resource set and

wherein the apparatus is further caused to:

determine if a configuration for the presence information is the same in the first and the second control resource sets; and,

determine, for the linked search space sets, and based on the determination, the presence information of the transmission configuration indication.

4 . The apparatus according to claim 3 , wherein the apparatus is further caused to:

determine a reference control resource set based on determining that the configuration for the presence information is not the same in the first and the second control resource sets; and

determine, for the linked search space sets, and based on the reference control set, the presence information of the transmission configuration indication.

5 . The apparatus according to claim 4 , wherein the reference control resource set is defined based on radio resource control parameters or based on medium access control element parameters.

6 . The apparatus according to claim 4 , wherein the apparatus is further caused to:

determine if the first or the second control resource set has a lowest identifier (ID) and further determine the reference control resource set to be the control resource set that has the lowest ID; or

determine if the first or the second control resource set has a highest ID, and further determine the reference control resource set to be the control resource set that has the highest ID.

7 . The apparatus according to claim 4 , wherein the reference control set comprises a control set corresponding to a reference search space set.

8 . The apparatus according to claim 4 , wherein the apparatus is further caused to:

receive, from a network node, a first dynamic indication to change the presence information of the transmission configuration indication associated with the first control resource set or with the second control resource set; and

updating the control resource set to the control resource set the transmission configuration indication is associated with.

9 . The apparatus according to claim 4 , wherein the apparatus is further caused to:

receive, from a network node, a second dynamic indication to change the linking of the first and the second search space sets; and

update the reference control resource set based on the changed linking.

10 . The apparatus according to claim 3 , wherein the apparatus is further caused to, if the configuration for the presence information is not the same in the first and the second control resource sets, determine the field size of the transmission configuration indication in the downlink control information for the multiple transmission reception points physical downlink control channel repetition based on a pre-determined rule regarding a configuration regarding a transmission configuration indication comprised in the first or in the second control resources set.

11 . The apparatus according to claim 10 , wherein the pre-determined rule comprises one of the following:

the presence information of the transmission configuration indication is enabled if the first search space set or the second search space set comprises the configuration for the presence information as enabled, otherwise the presence information of the transmission configuration is disabled; or

the presence information of the transmission configuration indication is enabled if the first search space set and the second search space set comprise the configuration for the presence information as enabled, otherwise the presence information of the transmission configuration is disabled.

12 . The apparatus according to claim 1 wherein the indication indicating a validity of the linkage is received via the medium access control control element.

13 . The apparatus according to claim 1 , wherein the apparatus is further caused to obtain, from a network node, and via a medium access control control element, an indication that the linkage is to be updated such that it is switched from the second search space set to a third search space set associated with a third control resource set.

14 . A method comprising:

obtaining information regarding a linkage of a first search space set and a second search space set, wherein the first search space set and the second search space set are different search spaces and are associated with a multi transmission reception point physical downlink control channel repetition, and the first search space is associated with a first transmission reception point and the second search space is associated with a second transmission reception point;

determining, based on the obtained information, that the first search space set and the second search space set are linked search space sets, and the linking is based on radio resource control configuration or a medium access control control element;

determining, for the linked search space sets, a presence information of a transmission configuration indication, wherein the presence information indicates if the transmission configuration indication is enabled or disabled; and

based on the presence information, determining a field size of the transmission configuration indication in a downlink control information for the multiple transmission reception point physical downlink control channel repetition,

wherein the method further comprises, receiving, from a network node, an indication indicating a validity of the linkage.

15 . The method according to claim 14 , wherein the presence information is determined based on a pre-determined rule or a pre-determined default value.

16 . The method according to claim 14 , wherein the first search space set is associated with a first control resource set and the second search space set is associated with a second control resource set

and wherein the method further comprises:

determining if a configuration for the presence information is the same in the first and the second control resource sets; and,

determining, for the linked search space sets, and based on the determination, the presence information of the transmission configuration indication.

17 . The method according to claim 16 , wherein the method further comprises:

determining a reference control resource set based on determining that the configuration for the presence information is not the same in the first and the second control resource sets; and

determining, for the linked search space sets, and based on the reference control set, the presence information of the transmission configuration indication.

18 . The method according to claim 17 , wherein the reference control resource set is defined based on radio resource control parameters or based on medium access control element parameters.

19 . A non-transitory computer readable medium comprising instructions, when executed by an apparatus, cause the apparatus to perform at least the following:

obtaining information regarding a linkage of a first search space set and a second search space set, wherein the first search space set and the second search space set are different search spaces and are associated with a multi transmission reception point physical downlink control channel repetition, and the first search space is associated with a first transmission reception point and the second search space is associated with a second transmission reception point;

determining, based on the obtained information, that the first search space set and the second search space set are linked search space sets, and the linking is based on radio resource control configuration or a medium access control control element;

determining, for the linked search space sets, a presence information of a transmission configuration indication, wherein the presence information indicates if the transmission configuration indication is enabled or disabled; and

based on the presence information, determining a field size of the transmission configuration indication in a downlink control information for the multiple transmission reception point physical downlink control channel repetition,

wherein the apparatus is further caused to perform receiving, from a network node, an indication indicating a validity of the linkage.