Implicit system information (SI) content variation enabling soft combining

1. A network node, comprising:

processing circuitry configured to:

prepare a set of system information transmissions, wherein each transmission within the set comprises system information, and wherein the set of transmissions enable soft combining by configuring a portion of the system information to be the same for each transmission within the set; and

for each transmission, prepare an indication of an identifier associated with the respective transmission, the indication provided other than in the system information; and

an interface configured to transmit the set of system information transmissions and the indication of the identifier associated with each respective transmission wherein the interface is configured to transmit the set of system information transmissions using a sweep of narrow beams that provide spatial repetition of the system informationUs.

2. The network node of claim 1 , wherein each transmission within the set has an associated transmission number and the transmission number can be derived at least in part from the identifier provided by the indication.

3. The network node of claim 1 , wherein each transmission within the set has an associated symbol number and the identifier provided by the indication corresponds to the symbol number of the respective transmission.

4. The network node of claim 1 , wherein a portion of the system information comprises contents that depend on the identifier associated with the respective transmission.

5. The network node of claim 1 , wherein a physical random access channel (PRACH) configuration depends on the identifier associated with the respective transmission such that the PRACH configuration associated with one of the transmissions differs from the PRACH configuration associated with another of the transmissions.

6. The network node of claim 1 , wherein the processing circuitry is further configured to prepare a second set of system information transmissions, wherein the indication enables a wireless device to determine that the transmissions belonging to the first set of system information transmissions cannot be soft-combined with the transmissions belonging to the second set of system information transmissions; and

the interface is further configured to transmit the second set of system information.

7. The network node of any of claim 1 , wherein the processing circuitry is further configured to prepare a second set of system information transmissions, wherein the indication provided other than in the system information together with an explicit indication provided in each system information transmission in the first and second sets of system information transmissions enables a wireless device to determine that:

the transmissions belonging to the first set of system information transmissions cannot be soft-combined with the transmissions belonging to the second set of system information transmissions;

one of the transmissions belonging to the first set of system information transmissions is capable of being soft-combined with the other transmissions belonging to the first set of system information transmissions; and

one of the transmissions belonging to the second set of system information transmissions is capable of being soft-combined with the other transmissions belonging to the second set of system information transmissions; and

the interface is further configured to transmit the second set of system information.

8. The network node of claim 1 , wherein the indication enables a wireless device to determine that the transmissions belong to the set of system information transmissions and are therefore capable of being soft-combined.

9. The network node of claim 1 , wherein the indication provided other than in the system information together with an explicit indication provided in each system information transmission enables a wireless device to determine that the transmissions belong to the set of system information transmissions and are therefore capable of being soft-combined.

10. The network node of claim 1 , wherein:

the set of system information transmissions comprises a plurality of subsets of transmission; and

the indication enables coherently soft-combining transmissions within the same subset and non-coherently soft-combining transmissions within different subsets.

11. A method for use in a wireless device, the method comprising:

receiving a plurality of system information transmissions, each transmission comprising system information;

for each transmission, determining an indication of an identifier associated with the respective transmission, the indication received other than in the system information, wherein the indication indicates whether the received transmissions belong to a set of system information transmissions for which a portion of the system information is configured to be the same for each transmission within the set such that soft-combining is enabled, wherein the set of system information transmissions comprises a sweep of narrow beams that provide spatial repetition of the system information; and

soft-combining the received transmissions for which soft-combining is enabled.

12. The method of claim 11 , wherein each transmission within the set has an associated transmission number and the transmission number can be derived at least in part from the identifier received in the indication.

13. The method of claim 11 , wherein each transmission within the set has an associated symbol number and the identifier received in the indication corresponds to the symbol number of the respective transmission.

14. The method of claim 11 , further comprising:

determining a portion of the system information that is the same for each transmission in the set based on the soft-combining of the received transmissions; and

determining a transmission-specific portion of the system information from only one of the transmissions.

15. The method of claim 11 , wherein a physical random access channel (PRACH) configuration depends on the identifier associated with the respective transmission such that the PRACH configuration associated with one of the transmissions differs from the PRACH configuration associated with another of the transmissions.

16. The method of claim 11 , wherein the indication is determined by decoding the indication from a reference signal.

17. The method of claim 11 , wherein the indication is determined based on different scrambling used for each transmission within the set.

18. The method of claim 11 , receiving a second set of system information transmissions;

determining, based on the indication, that the transmissions belonging to the first set of system information transmissions cannot be soft-combined with the transmissions belonging to the second set of system information transmissions.

19. The method of claim 11 , further comprising

receiving a second set of system information transmissions;

determining, based on the indication received other than in the system information together with an explicit indication received in each system information transmission in the first and second sets of system information transmissions that:

the transmissions belonging to the first set of system information transmissions cannot be soft-combined with the transmissions belonging to the second set of system information transmissions;

one of the transmissions belonging to the first set of system information transmissions is capable of being soft-combined with the other transmissions belonging to the first set of system information transmissions; and

one of the transmission belonging to the second set of system information transmissions is capable of being soft-combined with the other transmissions belonging to the second set of system information transmissions.

20. The method of claim 11 , wherein the indication received other than in the system information together with an explicit indication received in each system information transmission enables the wireless device to determine that the transmissions belong to the set of system information transmissions and are therefore capable of being soft-combined.

21. The method of claim 11 , further comprising:

determining, based on the indication, that the set of system information transmissions comprises a plurality of subsets of transmissions such that transmissions within the same subset are capable of being coherently soft-combined and transmissions within different subsets can only be non-coherently soft-combined.

22. A wireless device, comprising:

an interface configured to receive a plurality of system information transmissions, each transmission comprising system information; and

processing circuitry configured to:

for each transmission, determine an indication of an identifier associated with the respective transmission, the indication received other than in the system information, wherein the indication indicates whether the received transmissions belong to a set of system information transmissions for which a portion of the system information is configured to be the same for each transmission within the set such that soft-combining is enabled, wherein the set of system information transmissions comprises a sweep of narrow beams that provide spatial repetition of the system information; and

soft-combine the received transmissions for which soft-combining is enabled.

23. The wireless device of claim 22 , wherein each transmission within the set has an associated transmission number and the transmission number can be derived at least in part from the identifier received in the indication.

24. The wireless device of claim 22 , wherein each transmission within the set has an associated symbol number and the identifier received in the indication corresponds to the symbol number of the respective transmission.

25. The wireless device of claim 22 , the processing circuitry further configured to:

determine a portion of the system information that is the same for each transmission in the set based on the soft-combining of the received transmissions; and

determine a transmission-specific portion of the system information from only one of the transmissions.

26. The wireless device of claim 22 , wherein a physical random access channel (PRACH) configuration depends on the identifier associated with the respective transmission such that the PRACH configuration associated with one of the transmissions differs from the PRACH configuration associated with another of the transmissions.

27. The wireless device of claim 22 , wherein the indication is determined by decoding the indication from a reference signal.

28. The wireless device of claim 22 , wherein:

the interface is further configured to receive a second set of system information transmissions; and

the processing circuitry is further configured to determine, based on the indication, that the transmissions belonging to the first set of system information transmissions cannot be soft-combined with the transmissions belonging to the second set of system information transmissions.

29. The wireless device of claim 22 , wherein:

the interface is further configured to receive a second set of system information transmissions; and

the processing circuitry is further configured to determine based on the indication received other than in the system information together with an explicit indication received in each system information transmission in the first and second sets of system information transmissions that:

the transmissions belonging to the first set of system information transmissions cannot be soft-combined with the transmissions belonging to the second set of system information transmissions;

one of the transmissions belonging to the first set of system information transmissions is capable of being soft-combined with the other transmissions belonging to the first set of system information transmissions; and

one of the transmission belonging to the second set of system information transmissions is capable of being soft-combined with the other transmissions belonging to the second set of system information transmissions.

30. The wireless device of claim 22 , wherein the indication received other than in the system information together with an explicit indication received in each system information transmission enables the wireless device to determine that the transmissions belong to the set of system information transmissions and are therefore capable of being soft-combined.

31. The wireless device of claim 22 , the processing circuitry further configured to:

determine, based on the indication, that the set of system information transmissions comprises a plurality of subsets of transmissions such that transmissions within the same subset are capable of being coherently soft-combined and transmissions within different subsets can only be non-coherently soft-combined.