Non-transparent inband relay node in a single frequency network
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive, for a base station, a configuration message indicating a set of random access resources associated with monitoring by a relay node. The UE may transmit a random access message using the random access resources to the relay node and a timing advance associated with uplink data transmissions by the UE. The UE may then communicate with the base station via the relay node based on the random access message. In some examples, a UE may monitor for a relay reference signal from a relay node. The UE may determine a signal strength and a timing of the relay reference signal. The UE may determine whether an RSRP satisfies a threshold receive power, and may determine whether the timing of the relay reference signal is less than a timing threshold. The UE may transmit a downlink relay request to the base station to initiate relay communications.
1. A method for wireless communications at a user equipment (UE), comprising:
receiving, from a network entity, a configuration message indicating a set of random access resources associated with monitoring by a relay node;
transmitting, based at least in part on the configuration message, a random access message using the set of random access resources associated with monitoring by the relay node, wherein the random access message uses a timing advance associated with uplink data transmissions by the UE, wherein a transmission timing between the UE and the relay node is based at least in part on the timing advance; and
communicating with the network entity via the relay node based at least in part on the random access message and based at least in part on the transmission timing satisfying a threshold.
2. The method of claim 1 , further comprising:
determining an uplink timing advance value based at least in part on a second transmission timing of a physical uplink shared channel (PUSCH); and
applying the uplink timing advance value to the random access message, wherein transmitting the random access message is according to the uplink timing advance value.
3. The method of claim 1 , wherein the configuration message comprises a control message indicating that the random access message is to be transmitted according to a timing advance value.
4. The method of claim 3 , wherein the control message comprises downlink control information for triggering contention free random access (CFRA) transmission, the downlink control information comprising a one-bit indicator.
5. A method for wireless communications at a user equipment (UE), comprising:
monitoring a relay reference signal from a relay node;
determining a signal strength of the relay reference signal and a timing of the relay reference signal based at least in part on the monitoring; and
transmitting, to a network entity, a downlink relay request based at least in part on the timing of the relay reference signal satisfying a threshold timing value.
6. The method of claim 5 , wherein determining a signal strength of the relay reference signal comprises:
receiving, based at least in part on the monitoring, the relay reference signal from the relay node;
performing one or more measurements on the relay reference signal; and
determining, based at least in part on the one or more measurements, whether a reference signal receive power (RSRP) of the relay reference signal satisfies a power threshold, wherein transmitting the downlink relay request is based at least in part on determining that the RSRP of the relay reference signal satisfies the power threshold.
7. The method of claim 5 , wherein determining the timing of the relay reference signal comprises:
receiving, based at least in part on the monitoring, the relay reference signal from the relay node;
comparing the timing of the relay reference signal to the threshold timing value; and
determining, based at least in part on the comparing, whether the timing of the relay reference signal satisfies the threshold timing value, wherein transmitting the downlink relay request is based at least in part on determining that the timing of the relay reference signal satisfies the threshold timing value.
8. The method of claim 5 , wherein the downlink relay request includes an indication of the relay node.
9. The method of claim 5 , wherein the relay reference signal is a channel state information reference signal (CSI-RS).
10. The method of claim 5 , wherein the relay reference signal is a synchronization signal block (SSB) not on a sync raster.
11. The method of claim 5 , further comprising:
receiving a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for receiving downlink relay transmissions from the relay node;
receiving a second configuration message indicating a second set of TTIs allocated for receiving downlink transmissions from the network entity;
identifying, based at least in part on the first set of TTIs and the second set of TTIs, a third set of TTIs allocated for receiving downlink relay transmissions from the relay node, downlink transmissions from the network entity, or both; and
performing a cross-TTI channel estimation based at least in part on the identifying.
12. The method of claim 11 , further comprising:
identifying a first receive beam, wherein receiving the first configuration message comprises receiving the first configuration message via the first receive beam; and
identifying a second receive beam, wherein receiving the second configuration message comprises receiving the second configuration message via the second receive beam.
13. The method of claim 11 , further comprising:
monitoring one or more of the first set of TTIs, the second set of TTIs, and the third set of TTIs, based at least in part on the identifying; and
receiving, based at least in part on the monitoring, downlink relay transmissions from the relay node during the first set of TTIs, the third set of TTIs, or both, or downlink transmissions from the network entity during the second set of TTIs, the third set of TTIs, or both, or a combination thereof.
14. The method of claim 11 , further comprising:
receiving, during the third set of TTIs, a downlink transmission from the network entity and a downlink relay transmission from the relay node, wherein the downlink transmission and the downlink relay transmission are frequency division multiplexed.
15. The method of claim 11 , wherein performing the cross-TTI channel estimation comprises:
performing a first cross-TTI channel estimation for the first set of TTIs, a second cross-TTI channel estimation for the second set of TTIs, a third cross-TTI channel estimation for the third set of TTIs, or a combination thereof.
16. The method of claim 11 , further comprising:
reporting, to the relay node, first channel state information corresponding to the first set of TTIs, the third set of TTIs, or both; and
reporting, to the network entity, second channel state information corresponding to the second set of TTIs, the third set of TTIs, or both.
17. The method of claim 16 , further comprising:
generating a beam report for subsequent communications; and
incorporating the beam report in the first channel state information, the second channel state information, or both.
18. An apparatus for wireless communications at a user equipment (UE), comprising:
a processor,
memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
receive, from a network entity, a configuration message indicating a set of random access resources associated with monitoring by a relay node;
transmit, based at least in part on the configuration message, a random access message using the set of random access resources associated with monitoring by the relay node, wherein the random access message uses a timing advance associated with uplink data transmissions by the UE, wherein a transmission timing between the UE and the relay node is based at least in part on the timing advance; and
communicate with the network entity via the relay node based at least in part on the random access message and based at least in part on the transmission timing satisfying a threshold.
19. The apparatus of claim 18 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine an uplink timing advance value based at least in part on a second transmission timing of a physical uplink shared channel (PUSCH); and
apply the uplink timing advance value to the random access message, wherein transmitting the random access message is according to the uplink timing advance value.
20. The apparatus of claim 18 , wherein the configuration message comprises a control message indicating that the random access message is to be transmitted according to a timing advance value.
21. The apparatus of claim 20 , wherein the control message comprises downlink control information for triggering contention free random access (CFRA) transmission, the downlink control information comprising a one-bit indicator.
22. An apparatus for wireless communications at a user equipment (UE), comprising:
a processor,
memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
monitor a relay reference signal from a relay node;
determine a signal strength of the relay reference signal and a timing of the relay reference signal based at least in part on the monitoring; and
transmit, to a network entity, a downlink relay request based at least in part on the timing of the relay reference signal satisfying a threshold timing value.
23. The apparatus of claim 22 , wherein the instructions to determine the signal strength of the relay reference signal are executable by the processor to cause the apparatus to:
receive, based at least in part on the monitoring, the relay reference signal from the relay node;
perform one or more measurements on the relay reference signal; and
determine, based at least in part on the one or more measurements, whether a reference signal receive power (RSRP) of the relay reference signal satisfies a power threshold, wherein transmitting the downlink relay request is based at least in part on determining that the RSRP of the relay reference signal satisfies the power threshold.
24. The apparatus of claim 22 , wherein the instructions to determine the timing of the relay reference signal are executable by the processor to cause the apparatus to:
receive, based at least in part on the monitoring, the relay reference signal from the relay node;
compare the timing of the relay reference signal to the threshold timing value; and
determine, based at least in part on the comparing, whether the timing of the relay reference signal satisfies the threshold timing value, wherein transmitting the downlink relay request is based at least in part on determining that the timing of the relay reference signal satisfies the threshold timing value.
25. The apparatus of claim 22 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive a first configuration message indicating a first set of transmission time intervals (TTIs) allocated for receiving downlink relay transmissions from the relay node;
receive a second configuration message indicating a second set of TTIs allocated for receiving downlink transmissions from the network entity;
identify, based at least in part on the first set of TTIs and the second set of TTIs, a third set of TTIs allocated for receiving downlink relay transmissions from the relay node, downlink transmissions from the network entity, or both; and
perform a cross-TTI channel estimation based at least in part on the identifying.
26. The apparatus of claim 25 , wherein the instructions are further executable by the processor to cause the apparatus to:
identify a first receive beam, wherein receiving the first configuration message are executable by the processor to cause the apparatus to receive the first configuration message via the first receive beam; and
identify a second receive beam, wherein receiving the second configuration message are executable by the processor to cause the apparatus to receive the second configuration message via the second receive beam.
27. The apparatus of claim 25 , wherein the instructions are further executable by the processor to cause the apparatus to:
monitor one or more of the first set of TTIs, the second set of TTIs, and the third set of TTIs, based at least in part on the identifying; and
receive, based at least in part on the monitoring, downlink relay transmissions from the relay node during the first set of TTIs, the third set of TTIs, or both, or downlink transmissions from the network entity during the second set of TTIs, the third set of TTIs, or both, or a combination thereof.
28. The apparatus of claim 25 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive, during the third set of TTIs, a downlink transmission from the network entity and a downlink relay transmission from the relay node, wherein the downlink transmission and the downlink relay transmission are frequency division multiplexed.
29. The apparatus of claim 25 , wherein the instructions to perform the cross-TTI channel estimation are executable by the processor to cause the apparatus to:
perform a first cross-TTI channel estimation for the first set of TTIs, a second cross-TTI channel estimation for the second set of TTIs, a third cross-TTI channel estimation for the third set of TTIs, or a combination thereof.
30. The apparatus of claim 25 , wherein the instructions are further executable by the processor to cause the apparatus to:
report, to the relay node, first channel state information corresponding to the first set of TTIs, the third set of TTIs, or both; and
report, to the network entity, second channel state information corresponding to the second set of TTIs, the third set of TTIs, or both.