Aperiodic signal transmission for initial access
Methods, systems, and devices for wireless communications are described. A base station may transmit, to a user equipment (UE), an aperiodic synchronization signal block comprising an indication timing for receipt of an aperiodic remaining system information transmission. The UE may receive the aperiodic synchronization signal block and monitor for the aperiodic remaining system information based on receiving the aperiodic synchronization signal block. The base station may transmit, to the UE, the aperiodic remaining system information comprising an indication of timing for one or more occasions for physical random access channel transmission. The UE may receive the aperiodic remaining system information based on the timing for receipt included in the aperiodic synchronization signal block and select at least one occasion for the physical random access channel transmission based on the timing.
1 . A method for wireless communication at a user equipment (UE), comprising:
monitoring for one or more synchronization signal blocks from a network device;
receiving a first aperiodic synchronization signal block based at least in part on the monitoring, the first aperiodic synchronization signal block comprising an indication of a timing of a first occasion corresponding to a receipt of a first aperiodic remaining minimum system information and a timing of a second occasion corresponding to a receipt of a retransmission of the first aperiodic remaining minimum system information; and
monitoring for the first aperiodic remaining minimum system information during the first occasion or the retransmission of the first aperiodic remaining minimum system information during the second occasion, or both, based at least in part on receiving the first aperiodic synchronization signal block.
2 . The method of claim 1 , further comprising:
receiving, from the network device, the first aperiodic remaining minimum system information based at least in part on the timing of the first occasion;
determining that the first aperiodic remaining minimum system information comprises an indication of timing corresponding to one or more occasions for physical random access channel transmission; and
selecting at least one occasion for the physical random access channel transmission based at least in part on the timing corresponding to the one or more occasions for the physical random access channel transmission.
3 . The method of claim 1 , further comprising:
determining that the first aperiodic synchronization signal block comprises location information corresponding to the receipt of the first aperiodic remaining minimum system information; and
receiving the first aperiodic remaining minimum system information based at least in part on the location information corresponding to the receipt of the first aperiodic remaining minimum system information.
4 . The method of claim 3 , wherein the location information indicates a location for receiving the first aperiodic remaining minimum system information with respect to the timing of the first occasion.
5 . The method of claim 1 , further comprising:
receiving a second aperiodic synchronization signal block based at least in part on the monitoring;
determining that the second aperiodic synchronization signal block lacks timing information corresponding to reception of a second aperiodic remaining minimum system information; and
refraining from performing a demodulation reference signal scrambling for the second aperiodic remaining minimum system information using the timing information based at least in part on the second aperiodic synchronization signal block lacking timing information corresponding to the reception of the second aperiodic remaining minimum system information.
6 . The method of claim 1 , further comprising:
receiving the first aperiodic remaining minimum system information based at least in part on the indication of the first occasion included in the first aperiodic synchronization signal block; and
receiving the retransmission of the first aperiodic remaining minimum system information based at least in part on the indication of the second occasion included in the first aperiodic synchronization signal block.
7 . The method of claim 1 , further comprising:
determining that a physical downlink control channel or a physical downlink shared channel associated with the first aperiodic remaining minimum system information is not received at the UE;
monitoring for a third aperiodic synchronization signal block based at least in part on determining that the physical downlink control channel or the physical downlink shared channel associated with the first aperiodic remaining minimum system information is not received at the UE;
receiving the third aperiodic synchronization signal block comprising an indication of a timing corresponding to a receipt of a third aperiodic remaining minimum system information; and
receiving the third aperiodic remaining minimum system information based at least in part on the timing corresponding to the receipt of the third aperiodic remaining minimum system information included in the third aperiodic synchronization signal block.
8 . The method of claim 1 , further comprising:
receiving, from the network device, a plurality of aperiodic remaining minimum system information transmissions indicated by the first aperiodic synchronization signal block, wherein the first aperiodic synchronization signal block comprises an indication of timing corresponding to a receipt of a plurality of aperiodic remaining minimum system information transmissions.
9 . The method of claim 1 , further comprising:
determining that the first aperiodic remaining minimum system information associated with a first beam indicates a second beam corresponding to selecting an occasion for a physical random access channel transmission; and
selecting the occasion for the physical random access channel transmission based at least in part on the determining.
10 . The method of claim 1 , further comprising:
receiving, from the network device, a type indication indicating the first aperiodic synchronization signal block, wherein monitoring for the one or more synchronization signal blocks is based at least in part on the type indication.
11 . The method of claim 10 , wherein the type indication is transmitted in a physical broadcast channel transmission or a demodulation reference signal associated with the physical broadcast channel transmission.
12 . The method of claim 1 , wherein the UE uses the first aperiodic synchronization signal block to perform an initial access operation.
13 . The method of claim 1 , wherein the first aperiodic synchronization signal block comprises a cell defining synchronization signal block.
14 . The method of claim 1 , wherein the first aperiodic synchronization signal block and a periodic synchronization signal block are associated with at least one of different synchronization rasters, different primary synchronization signal sets, different secondary synchronization signal sets, or a combination thereof.
15 . A method for wireless communication at a network device, comprising:
determining a transmission time for a first aperiodic synchronization signal block based at least in part on one or more parameters; and
transmitting, to a user equipment (UE), the first aperiodic synchronization signal block at the determined transmission time, the first aperiodic synchronization signal block comprising an indication of a timing of a first occasion corresponding to a receipt of a first aperiodic remaining minimum system information and a timing of a second occasion corresponding to a receipt of a retransmission of the first aperiodic remaining minimum system information.
16 . The method of claim 15 , further comprising:
transmitting, to the UE, the first aperiodic remaining minimum system information comprising an indication of a timing of one or more occasions for physical random access channel transmission; and
receiving, from the UE, the physical random access channel transmission based at least in part on the timing corresponding to the one or more occasions for the physical random access channel transmission.
17 . The method of claim 15 , further comprising:
determining that the first aperiodic synchronization signal block comprises location information corresponding to the receipt of the first aperiodic remaining minimum system information; and
transmitting the first aperiodic remaining minimum system information based at least in part on the location information corresponding to the receipt of the first aperiodic remaining minimum system information.
18 . The method of claim 17 , wherein the location information indicates a location for the first aperiodic remaining minimum system information with respect to the timing corresponding to the receipt of the first aperiodic synchronization signal block.
19 . The method of claim 15 , further comprising:
transmitting the first aperiodic remaining minimum system information based at least in part on the indication of the first occasion included in the first aperiodic synchronization signal block; and
transmitting the retransmission of the first aperiodic remaining minimum system information based at least in part on the indication of the second occasion included in the first aperiodic synchronization signal block.
20 . The method of claim 15 , further comprising:
transmitting, to the UE, a plurality of aperiodic remaining minimum system information transmissions indicated by the first aperiodic synchronization signal block, wherein the first aperiodic synchronization signal block comprises an indication of timing corresponding to a receipt of a plurality of aperiodic remaining minimum system information transmissions.
21 . The method of claim 15 , further comprising:
transmitting, to the UE, a type indication indicating the first aperiodic synchronization signal block, wherein transmitting the first aperiodic synchronization signal block is based at least in part on the type indication.
22 . The method of claim 21 , wherein the type indication is transmitted in a physical broadcast channel transmission or a demodulation reference signal associated with the physical broadcast channel transmission.
23 . The method of claim 15 , wherein the one or more parameters comprise an availability of resources or a traffic condition or both.
24 . The method of claim 15 , wherein the first aperiodic synchronization signal block comprises a cell defining synchronization signal block.
25 . The method of claim 15 , wherein the first aperiodic synchronization signal block and a periodic synchronization signal block are associated with at least one of different synchronization rasters, different primary synchronization signal sets, different secondary synchronization signal sets, or a combination thereof.
26 . An apparatus for wireless communication at a user equipment (UE), comprising:
one or more processors;
one or more memories coupled with the one or more processors; and
instructions stored in the one or more memories and executable by the one or more processors to cause the apparatus to:
monitor for one or more synchronization signal blocks from a network device;
receive a first aperiodic synchronization signal block based at least in part on the monitoring, the first aperiodic synchronization signal block comprising an indication of a timing of a first occasion corresponding to a receipt of a first aperiodic remaining minimum system information and a timing of a second occasion corresponding to a receipt of a retransmission of the first aperiodic remaining minimum system information; and
monitor for the first aperiodic remaining minimum system information during the first occasion or the retransmission of the first aperiodic remaining minimum system information during the second occasion, or both, based at least in part on receiving the first aperiodic synchronization signal block.
27 . The apparatus of claim 26 , wherein the instructions are further executable by the one or more processors to cause the apparatus to:
receive, from the network device, the first aperiodic remaining minimum system information based at least in part on the timing of the first occasion;
determine that the first aperiodic remaining minimum system information comprises an indication of timing corresponding to one or more occasions for physical random access channel transmission; and
select at least one occasion for the physical random access channel transmission based at least in part on the timing corresponding to the one or more occasions for the physical random access channel transmission.
28 . The apparatus of claim 26 , wherein the instructions are further executable by the one or more processors to cause the apparatus to:
determine that the first aperiodic synchronization signal block comprises location information corresponding to the receipt of the first aperiodic remaining minimum system information; and
receive the first aperiodic remaining minimum system information based at least in part on the location information corresponding to the receipt of the first aperiodic remaining minimum system information.
29 . The apparatus of claim 28 , wherein the location information indicates a location for receiving the first aperiodic remaining minimum system information with respect to a timing corresponding to the receipt of the first aperiodic synchronization signal block.
30 . An apparatus for wireless communication at a network device, comprising:
one or more processors;
one or more memories coupled with the one or more processors; and
instructions stored in the one or more memories and executable by the one or more processors to cause the apparatus to:
determine a transmission time for a first aperiodic synchronization signal block based at least in part on one or more parameters; and
transmit, to a user equipment (UE), the first aperiodic synchronization signal block at the determined transmission time, the first aperiodic synchronization signal block comprising an indication of a timing of a first occasion corresponding to a receipt of a first aperiodic remaining minimum system information and a timing of a second occasion corresponding to a receipt of a retransmission of the first aperiodic remaining minimum system information.