Discovery signals for mobile relays

1 . A method of wireless communication at a mobile relay, comprising:

generating a synchronization signal/physical broadcast channel block (SSB) for the mobile relay using:

a primary synchronization signal (PSS) for mobile relays that is different than a stationary base station PSS, wherein a sequence of the PSS for the mobile relays is different than a stationary base station PSS sequence based on a set value to initialize a register x for generating the sequence, a value m to map the register x to the sequence, and a rule to update the register x each being different for the mobile relays than for stationary base stations, the set value to initialize the register x for the stationary base stations being [x(6) x(5) x(4) x(3) x(2) x(1) x(0)]=[1 1 1 0 1 1 0], the value m to map the register x for the stationary base stations being m=(n+43N ID (2) ) mod 127, and the rule to update the register x for the stationary base stations being x(i+7)=(x(i+4)+x(i)) mod 2, wherein n, i, and N ID (2) are numeric values;

and using at least one of:

a secondary synchronization signal (SSS) for the mobile relays that is different than a stationary base station SSS,

a physical broadcast channel (PBCH) for the mobile relays that is different than a stationary base station PBCH; and

a demodulation reference signal (DMRS) associated with the PBCH for the mobile relays that is different than a stationary base station DMRS; and

broadcasting the SSB.

2 . The method of claim 1 , wherein the mobile relay uses the PSS for the mobile relays that is different than the stationary base station PSS, or the SSS for the mobile relays that is different than the stationary base station SSS.

3 . The method of claim 2 , wherein the mobile relay uses a symbol placement for the PSS or the SSS that is different than a stationary base station symbol placement, the stationary base station symbol placement for the PSS being a first symbol of the SSB, and the symbol placement of the mobile relay for the PSS being a different symbol than the first symbol of the SSB.

4 . The method of claim 2 , wherein the mobile relay uses an SSS sequence that is different than a stationary base station SSS sequence.

5 . The method of claim 1 , wherein the mobile relay uses the PBCH that is different than the stationary base station PBCH.

6 . The method of claim 5 , wherein the mobile relay applies a different scrambling to the PBCH than the stationary base station PBCH or applies a different scrambling to the DMRS associated with the PBCH.

7 . The method of claim 6 , wherein the different scrambling includes at least one of a first function for a scrambling initialization or a second function for applying the scrambling to the PBCH that is different than for the stationary base station.

8 . The method of claim 1 , wherein the mobile relay transmits the SSB using at least one raster frequency from a set of raster frequencies for mobile relays.

9 . The method of claim 8 , wherein the at least one raster frequency is based on a raster offset in frequency for the mobile relays.

10 . The method of claim 1 , wherein a physical cell identity (PCI) for the mobile relay is from a PCI pool for the mobile relays that is larger than a stationary base station PCI pool.

11 . The method of claim 10 , wherein the PCI pool for the mobile relays includes a set of SSS sequences that is larger than a stationary base station set of SSS sequences.

12 . The method of claim 10 , wherein the PCI for the mobile relay is indicated based on the PSS, the SSS, and at least one of the PBCH or the DMRS.

13 . The method of claim 10 , wherein the PCI for the mobile relay is indicated based on the PSS, the SSS, and an additional synchronization signal.

14 . The method of claim 13 , wherein scrambling for the PBCH or the DMRS is based on the PCI indicated by the PSS, the SSS, and the additional synchronization signal.

15 . The method of claim 1 , wherein generating the synchronization signal/physical broadcast channel block (SSB) for the mobile relay further comprises generating a tertiary synchronization signal (TSS) in addition to the PSS and the SSS.

16 . An apparatus for wireless communication at a mobile relay, comprising:

a memory; and

at least one processor coupled to the memory and configured to:

generate a synchronization signal/physical broadcast channel block (SSB) for the mobile relay using:

a primary synchronization signal (PSS) for mobile relays that is different than a stationary base station PSS, wherein a sequence of the PSS for the mobile relays is different than a stationary base station PSS sequence based on a set value to initialize a register x for generating the sequence, a value m to map the register x to the sequence, and a rule to update the register x each being different for the mobile relays than for stationary base stations, the set value to initialize the register x for the stationary base stations being [x(6) x(5) x(4) x(3) x(2) x(1) x(0)]=[1 1 1 0 1 1 0], the value m to map the register x for the stationary base stations being m=(n+43N ID (2) ) mod 127, and the rule to update the register x for the stationary base stations being x(i+7)=(x(i+4)+x(i)) mod 2, wherein n, i, and N ID (2) are numeric values;

and using at least one of:

a secondary synchronization signal (SSS) for the mobile relays that is different than a stationary base station SSS,

a physical broadcast channel (PBCH) for the mobile relays that is different than a stationary base station PBCH; and

a demodulation reference signal (DMRS) associated with the PBCH for the mobile relays that is different than a stationary base station DMRS; and

broadcast the SSB.