Synchronization signal for a broadcast channel
An apparatus are provided for wireless communication at a base station with improved PBCH construction and decoding. The base station apparatus constructs a PBCH payload, wherein a bit location is selected for encoding a plurality of bits of the PBCH based on an estimated reliability for the corresponding bits location wherein the plurality of bits comprises frozen bits, unknown bits that are unknown to a user equipment, and potentially known bits that are potentially known by the user equipment. The apparatus transmits the PBCH payload in at least one of a plurality of SS blocks. A UE receiving the PBCH decodes the PBCH based on a successive decoding order. The successive decoding order may be based on an estimated reliability for the corresponding bits, e.g., in which potentially known bits are decoded prior to unknown bits.
1. A method of wireless communication at a base station, comprising:
constructing a physical broadcast channel (PBCH) payload, wherein bit locations are selected for encoding a plurality of bits of the PBCH payload based on estimated reliabilities of the bit locations, wherein the plurality of bits comprise frozen bits, unknown bits that are unknown to a user equipment (UE), and potentially known bits that are potentially known by the UE, wherein at least a plurality of the potentially known bits comprising at least a part of timing information are given less reliable bit locations of the bit locations than the unknown bits; and
transmitting the PBCH payload in at least one of a plurality of synchronization signal (SS) blocks.
2. The method of claim 1 , wherein the timing information comprised in the potentially known bits includes timing information for a cell.
3. The method of claim 2 , wherein the timing information comprised in the potentially known bits includes at least a portion of a system frame number for the cell.
4. The method of claim 1 , wherein the frozen bits are given less reliable bit locations of the bit locations than the potentially known bits.
5. The method of claim 1 , wherein the potentially known bits comprise information capable of being claimed to the UE by a neighbor cell serving the UE.
6. The method of claim 1 , wherein the unknown bits comprise error detection bits.
7. The method of claim 1 , wherein the PBCH payload comprises a polar coded PBCH.
8. The method of claim 1 , wherein the potentially known bits comprise timing information for a cell that is applicable to a neighbor cell.
9. The method of claim 1 , wherein the timing information is associated with a synchronization between a cell and a neighbor cell.
10. An apparatus for wireless communication at a base station, comprising:
a memory; and at least one processor coupled to the memory, the memory and the at least one processor configured to:
construct a physical broadcast channel (PBCH) payload, wherein bit locations are selected for encoding a plurality of bits of the PBCH payload based on estimated reliabilities of the bit locations, wherein the plurality of bits comprise frozen bits, unknown bits that are unknown to a user equipment (UE), and potentially known bits that are potentially known by the UE, wherein at least a plurality of the potentially known bits comprising at least a part of timing information are given less reliable bit locations of the bit locations than the unknown bits; and
transmit the PBCH payload in at least one of a plurality of synchronization signal (SS) blocks.
11. The apparatus of claim 10 , wherein the timing information comprised in the potentially known bits includes timing information for a cell.
12. The apparatus of claim 11 , wherein the timing information comprised in the potentially known bits includes at least a portion of system frame number for the cell.
13. The apparatus of claim 10 , wherein the frozen bits are given less reliable bit locations of the bit locations than the potentially known bits.
14. The apparatus of claim 10 , wherein the potentially known bits comprise information capable of being indicated to the UE by a neighbor cell serving the UE.
15. The apparatus of claim 10 , wherein the unknown bits comprise error detection bits.
16. The apparatus of claim 8 , wherein the PBCH payload comprises a polar coded PBCH.
17. The apparatus of claim 10 , wherein the potentially known bits comprise timing information for a cell that is applicable to a neighbor cell.
18. The apparatus of claim 10 , wherein the timing information is associated with a synchronization between a cell and a neighbor cell.
19. A method of wireless communication at a user equipment (UE) served by a first cell, comprising:
receiving a physical broadcast channel (PBCH) payload of a second cell in at least one of a plurality of synchronization signal (SS) blocks, wherein each SS block comprises corresponding timing information, and wherein the PBCH payload comprises frozen bits, unknown bits that are unknown to the UE, and potentially known bits that are potentially known by the UE, wherein the potentially known bits comprise at least a part of timing information; and
decoding the PBCH payload based on a successive decoding order.
20. The method of claim 19 , wherein the timing information comprised in the potentially known bits includes timing information for the second cell.
21. The method of claim 20 , wherein the timing information comprised in the potentially known bits includes at least a portion of a system frame number for the second cell.
22. The method of claim 20 , further comprising:
receiving information corresponding to the potentially known bits from the first cell, wherein the UE uses the information from the first cell to decode the PBCH payload from the second cell.
23. The method of claim 19 , wherein the successive decoding order is based on estimated reliabilities for corresponding bits.
24. The method of claim 19 , wherein the potentially known bits comprise information provided to the UE by the first cell.
25. The method of claim 19 , wherein the PBCH payload comprises a polar coded PBCH.
26. The method of claim 19 , further comprising:
receiving, from the first cell, a plurality of potentially known bits corresponding to a cell identifier (ID) for the second cell prior to reporting a cell quality; and
detecting a cell ID of the second cell from a received SS block, wherein the PBCH payload is decoded based on the successive decoding order using the potentially known bits received from the first cell.
27. The method of claim 19 , further comprising:
detecting a cell identifier (ID) of the second cell from a received SS block;
reporting the cell ID of the second cell to the first cell; and
receiving, from the first cell, a plurality of potentially known bits corresponding to the cell ID for the second cell in response to the reporting the cell ID, wherein the PBCH payload is decoded based on the successive decoding order using the potentially known bits received from the first cell.
28. The method of claim 19 , wherein the potentially known bits comprise the timing information for the first cell that is applicable to the second cell.
29. The method of claim 19 , wherein the timing information is associated with a synchronization between the first cell and the second cell.
30. An apparatus for wireless communication at a user equipment (UE) served by a first cell, comprising:
a memory; and
at least one processor coupled to the memory, the memory and the at least one processor configured to:
receive a physical broadcast channel (PBCH) payload of a second cell in at least one of a plurality of synchronization signal (SS) blocks, wherein each SS block comprises corresponding timing information, and wherein the PBCH payload comprises frozen bits, unknown bits that are unknown to the UE, and potentially known bits that are potentially known by the UE, wherein the potentially known bits comprise at least a part of timing information; and
decode the PBCH payload based on a successive decoding order, wherein the potentially known bits are decoded prior to the unknown bits.
31. The apparatus of claim 30 , wherein the timing information comprised in the potentially known bits includes timing information for the second cell.
32. The apparatus of claim 31 , wherein the timing information comprised in the potentially known bits includes at least a portion of a system frame number for the second cell.
33. The apparatus of claim 31 , wherein the memory and the at least one processor are further configured to:
receive information corresponding to the potentially known bits from the first cell, wherein the UE uses the information from the first cell to decode the PBCH payload from the second cell.
34. The apparatus of claim 30 , wherein the successive decoding order is based on estimated reliabilities for corresponding bits.
35. The apparatus of claim 30 , wherein the potentially known bits comprise information provided to the UE by the first cell.
36. The apparatus of claim 30 , wherein the PBCH payload comprises a polar coded PBCH.
37. The apparatus of claim 30 , wherein the potentially known bits comprise timing information for the first cell that is applicable to the second cell.
38. The apparatus of claim 30 , wherein the timing information is associated with a synchronization between the first cell and the second cell.