Physical layer security for physical uplink control channel transmissions

1. A method for wireless communications by a user equipment (UE), comprising:

obtaining a key; and

using the key during physical layer signal processing of a physical uplink control channel (PUCCH) transmission having more than one symbol to provide security for the PUCCH transmission, wherein

the physical layer signal processing comprises:

converting information bits to a value I;

selecting a sequence of length N from a sequence pool based on the value I; and

mapping the sequence to N resource elements.

2. The method of claim 1 , wherein the physical layer signal processing comprises:

modulating coded information bits to generate a modulated signal;

generating a waveform after modulating the coded information bits; and

multiplexing a demodulation reference signal (DMRS) sequence in the waveform.

3. The method of claim 2 , wherein using the key during physical layer signal processing comprises performing a logical function with the key and at least one of:

the coded information bits before the modulating;

the DMRS sequence; or

a cell-specific sequence used for the PUCCH transmission.

4. The method of claim 3 , further comprising determining a DMRS configuration based on the key.

5. The method of claim 3 , further comprising swapping real and imaginary parts of the modulated signal.

6. The method of claim 2 , further comprising:

determining a phase shift based on the key; and

applying the phase shift to the modulated signal.

7. The method of claim 1 , wherein using the key during physical layer signal processing comprises performing a logical function with the key and at least a part of the value l.

8. The method of claim 7 , wherein:

the value l comprises at least first and second parts; and

different keys are used to perform the logical function with the first and second parts.

9. The method of claim 1 , wherein providing security for the PUCCH transmission comprises determining the mapping of the sequence to N resource elements based on the key.

10. The method of claim 1 , wherein:

frequency resources for the PUCCH transmission are determined according to a frequency hopping pattern based at least in part on the key.

11. The method of claim 10 , wherein part or all of the key is used to determine the frequency hopping pattern.

12. The method of claim 10 , wherein a logical function is performed with a configurable identifier and part or all of the key to determine the frequency hopping pattern.

13. The method of claim 12 , further comprising receiving signaling indicating at least one of the key, the configurable identifier, or another key used to generate the configurable identifier.

14. The method of claim 1 , further comprising receiving signaling indicating how the UE is to use the key to provide security for the PUCCH transmission.

15. A method for wireless communications by a network entity, comprising:

obtaining a key used to provide security for a physical uplink control channel (PUCCH) transmission having more than one symbol from a user equipment (UE); and

using the key during physical layer signal processing of the PUCCH received from the UE, wherein

the physical layer signal is received on N resource elements and processing comprises:

demapping a sequence from the N resource elements;

determining a value I associated with the sequence; and

obtaining a set of information bits based on the value I.

16. The method of claim 15 , wherein the physical layer signal processing comprises:

processing a demodulation reference signal (DMRS) sequence multiplexed with coded information bits in a received waveform; and

decoding the coded information bits.

17. The method of claim 16 , wherein using the key during physical layer signal processing comprises performing a logical function with the key and at least one of:

the coded information bits;

the DMRS sequence; or

a cell-specific sequence used for the PUCCH transmission.

18. The method of claim 17 , further comprising determining a DMRS configuration based on the key.

19. The method of claim 17 , further comprising swapping real and imaginary parts of a received waveform before demodulation.

20. The method of claim 16 , further comprising:

determining a phase shift based on the key; and

applying the phase shift before demodulating the received waveform.

21. The method of claim 15 , wherein using the key during physical layer signal processing comprises performing a logical function with the key to obtain at least a part of the value l.

22. The method of claim 21 , wherein:

the value l comprises at least first and second parts; and

different keys are used to perform the logical function with the first and second parts.

23. The method of claim 15 , wherein the processing comprises determining a mapping of the sequence to N resource elements based on the key.

24. The method of claim 15 , wherein:

frequency resources for the PUCCH transmission are determined according to a frequency hopping pattern based at least in part on the key.

25. The method of claim 24 , wherein part or all of the key is used to determine the frequency hopping pattern.

26. The method of claim 24 , wherein a logical function is performed with a configurable identifier and part or all of the key to determine the frequency hopping pattern.

27. The method of claim 26 , further comprising transmitting signaling, to the UE, indicating at least one of the key, the configurable identifier, or another key used to generate the configurable identifier.

28. The method of claim 15 , further comprising transmitting signaling, to the UE, indicating how the UE is to use the key to provide security for the PUCCH transmission.