Reconfigurable intelligent surface or repeater assisted synchronization signal block transmission and initial access
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a synchronization signal block (SSB) transmitted by a base station. The UE may receive system information that includes reconfigurable intelligent surface (RIS) or repeater assisted initial access information that identifies a set of SSBs that are associated with an RIS or a repeater and a modulation signature associated with the RIS or the repeater. The UE may selectively perform initial access using the SSB or search for another SSB based at least in part on the RIS or repeater assisted initial access information. Numerous other aspects are described.
1. A user equipment (UE) for wireless communication, comprising:
a memory; and
one or more processors, coupled to the memory, configured to:
receive a synchronization signal block (SSB) transmitted by a base station;
receive system information that includes initial access information that is reconfigurable intelligent surface (RIS) assisted initial access information or repeater assisted initial access information, the initial access information identifying a set of SSBs that are associated with an RIS or a repeater and the initial access information identifying a modulation signature associated with the RIS or the repeater; and
select between performing initial access using the SSB and searching for another SSB based at least in part on the initial access information.
2. The UE of claim 1 , wherein the one or more processors are further configured to:
detect, in connection with a determination that the SSB is in the set of SSBs that are associated with the RIS or the repeater, whether the SSB is modulated with the modulation signature associated with the RIS or the repeater.
3. The UE of claim 2 , wherein the one or more processors, to select between performing initial access using the SSB and searching for another SSB, are configured to:
perform initial access using the SSB based at least in part on detecting that the SSB is modulated with the modulation signature associated with the RIS or the repeater; or
search for another SSB to use to perform initial access based at least in part on detecting that the SSB is not modulated with the modulation signature associated with the RIS or the repeater.
4. The UE of claim 3 , wherein the one or more processors, to perform initial access, are configured to:
perform RIS-assisted initial access using the SSB based at least in part on detecting that the SSB is modulated with the modulation signature associated with the RIS or the repeater.
5. The UE of claim 2 , wherein the modulation signature associated with the RIS or the repeater modulates at least one of a phase, an amplitude, a frequency, or a polarization at symbol boundaries of a signal redirected from the RIS or the repeater.
6. The UE of claim 1 , wherein the initial access information indicates respective SSB indices for one or more SSBs in the set of SSBs that are associated with the RIS or the repeater.
7. The UE of claim 1 , wherein the one or more processors, to select between performing initial access using the SSB and searching for another SSB, are configured to:
perform initial access using the SSB based at least in part on a determination that the SSB is not included in the set of SSBs associated with the RIS or the repeater.
8. A network entity for wireless communication, comprising:
a memory; and
one or more processors, coupled to the memory, configured to:
transmit a synchronization signal block (SSB) burst set including a first set of SSBs associated with direct transmission from the network entity and a second set of SSBs associated with a reconfigurable intelligent surface (RIS) or a repeater; and
transmit system information including initial access information that is RIS assisted initial access information or repeater assisted initial access information, the initial access information identifying the second set of SSBs as being associated with the RIS or the repeater and the initial access information identifying a modulation signature associated with the RIS or the repeater.
9. The network entity of claim 8 , wherein the modulation signature associated with the RIS or the repeater modulates at least one of a phase, an amplitude, a frequency, or a polarization at symbol boundaries of a signal redirected from the RIS or the repeater.
10. The network entity of claim 8 , wherein the one or more processors, to transmit the SSB burst set, are configured to:
transmit the second set of SSBs on a first beam toward the RIS or the repeater, wherein each SSB in the second set of SSBs is to be redirected by the RIS or the repeater and each SSB in the second set of SSBs is to be modulated by the RIS or repeater by the modulation signature associated with the RIS or the repeater.
11. The network entity of claim 10 , wherein the one or more processors are further configured to:
control the RIS or the repeater to redirect each SSB in the second set of SSBs and to modulate each SSB in the second set of SSBs by the modulation signature associated with the RIS or the repeater.
12. The network entity of claim 10 , wherein the one or more processors, to transmit the SSB burst set, are further configured to:
transmit an SSB in the first set of SSBs on the first beam or on a second beam that satisfies a distance threshold with respect to the first beam.
13. The network entity of claim 12 , wherein the one or more processors, to transmit the second set of SSBs on the first beam, are configured to transmit the second set of SSBs on the first beam at a first power, and wherein the one or more processors, to transmit the SSB in the first SSB burst set on the first beam or on the second beam that satisfies the distance threshold with respect to the first beam, are configured to transmit the SSB in the first SSB burst set on the first beam or on the second beam at a second power that is higher than the first power.
14. The network entity of claim 13 , wherein the one or more processors, to transmit the SSB in the first SSB burst set on the first beam or on the second beam at the second power, are configured to:
transmit the SSB in the first SSB burst set on the first beam or on the second beam using an increased radiated power from each antenna element of one or more antenna elements of an antenna array of the network entity, as compared with the radiated power used for transmitting the second set of SSBs on the first beam.
15. The network entity of claim 13 , wherein the one or more processors, to transmit the SSB in the first SSB burst set on the first beam or on the second beam at the second power, are configured to:
transmit the SSB in the first SSB burst set on the first beam or on the second beam using an increased beamforming gain, as compared with a beamforming gain used for transmitting the second set of SSBs on the first beam, while maintaining a same beam direction.
16. A method of wireless communication performed by a user equipment (UE), the method comprising:
receiving a synchronization signal block (SSB) transmitted by a base station;
receiving system information that includes initial access information that is reconfigurable intelligent surface (RIS) assisted initial access information or repeater assisted initial access information, the initial access information identifying a set of SSBs that are associated with an RIS or a repeater and the initial access information identifying a modulation signature associated with the RIS or the repeater; and
selecting between performing initial access using the SSB and searching for another SSB based at least in part on the initial access information.
17. The method of claim 16 , further comprising:
detecting, in connection with a determination that the SSB is in the set of SSBs that are associated with the RIS or the repeater, whether the SSB is modulated with the modulation signature associated with the RIS or the repeater.
18. The method of claim 17 , wherein selecting between performing initial access using the SSB and searching for another SSB comprises:
performing initial access using the SSB based at least in part on detecting that the SSB is modulated with the modulation signature associated with the RIS or the repeater; or
searching for another SSB to use to perform initial access based at least in part on detecting that the SSB is not modulated with the modulation signature associated with the RIS or the repeater.
19. The method of claim 18 , wherein performing initial access comprises:
performing RIS-assisted initial access using the SSB based at least in part on detecting that the SSB is modulated with the modulation signature associated with the RIS or the repeater.
20. The method of claim 17 , wherein the modulation signature associated with the RIS or the repeater modulates at least one of a phase, an amplitude, a frequency, or a polarization at symbol boundaries of a signal redirected from the RIS or the repeater.
21. The method of claim 16 , wherein the initial access information indicates respective SSB indices for one or more SSBs in the set of SSBs that are associated with the RIS or the repeater.
22. The method of claim 16 , wherein selecting between performing initial access using the SSB and searching for another SSB comprises:
performing initial access using the SSB based at least in part on a determination that the SSB is not included in the set of SSBs associated with the RIS or the repeater.
23. A method of wireless communication performed by a network entity, the method comprising:
transmitting a synchronization signal block (SSB) burst set including a first set of SSBs associated with direct transmission from the network entity and a second set of SSBs associated with a reconfigurable intelligent surface (RIS) or a repeater; and
transmitting system information including initial access information that is RIS assisted initial access information or repeater assisted initial access information, the initial access information identifying the second set of SSBs as being associated with the RIS or the repeater and the initial access information identifying a modulation signature associated with the RIS or the repeater.
24. The method of claim 23 , wherein the modulation signature associated with the RIS or the repeater modulates at least one of a phase, an amplitude, a frequency, or a polarization at symbol boundaries of a signal redirected from the RIS or the repeater.
25. The method of claim 23 , wherein transmitting the SSB burst set comprises:
transmitting the second set of SSBs on a first beam toward the RIS or the repeater, wherein each SSB in the second set of SSBs is to be redirected by the RIS or the repeater and each SSB in the second set of SSBs is to be modulated by the RIS or repeater by the modulation signature associated with the RIS or the repeater.
26. The method of claim 25 , further comprising:
controlling the RIS or the repeater to redirect each SSB in the second set of SSBs and to modulate each SSB in the second set of SSBs by the modulation signature associated with the RIS or the repeater.
27. The method of claim 25 , wherein transmitting the SSB burst set further comprises:
transmitting an SSB in the first set of SSBs on the first beam or on a second beam that satisfies a distance threshold with respect to the first beam.
28. The method of claim 27 , wherein transmitting the second set of SSBs on the first beam comprises transmitting the second set of SSBs on the first beam at a first power, and wherein transmitting the SSB in the first SSB burst set on the first beam or on the second beam that satisfies the distance threshold with respect to the first beam comprises transmitting the SSB in the first SSB burst set on the first beam or on the second beam at a second power that is higher than the first power.
29. The method of claim 28 , wherein transmitting the SSB in the first SSB burst set on the first beam or on the second beam at the second power comprises:
transmitting the SSB in the first SSB burst set on the first beam or on the second beam using an increased radiated power from each antenna element of one or more antenna elements of an antenna array of the network entity, as compared with the radiated power used for transmitting the second set of SSBs on the first beam.
30. The method of claim 28 , wherein transmitting the SSB in the first SSB burst set on the first beam or on the second beam at the second power comprises:
transmitting the SSB in the first SSB burst set on the first beam or on the second beam using an increased beamforming gain, as compared with a beamforming gain used for transmitting the second set of SSBs on the first beam, while maintaining a same beam direction.