Asynchronous carrier aggregation
Methods, systems, and devices for wireless communications are described that asynchronous carrier aggregation, including between high frequency band and lower frequency band transmissions. A user equipment (UE) may be configured to monitor transmissions in a first frequency band and a second frequency band. The UE may measure a timing difference between transmissions in the first frequency band and one or more of the transmissions in the second frequency band, and transmit an indication of the timing difference to a base station. The base station may use the timing difference to determine whether the UE is to use asynchronous carrier aggregation. If the base station determines that the UE is to use asynchronous carrier aggregation, the base station may configure the UE to observe at least a minimum amount of delay when conducting uplink signaling via one of the frequency bands.
1. An apparatus for wireless communication at a base station (BS), comprising:
one or more processors;
one or more memories coupled with the one or more processors; and
one or more processor-readable instructions stored in the one or more memories and executable by the one or more processors individually or collectively to cause the apparatus to:
establish a first connection between the BS and a user equipment (UE) using a first carrier, wherein a timing difference exists between transmissions using the first carrier and transmissions using a second carrier; and
transmit an indication to the UE that the UE is to establish a second connection for communications via the second carrier, wherein the second connection is in accordance with the timing difference.
2. The apparatus of claim 1 , wherein the timing difference is based at least in part on a timing offset between a first slot of the first carrier and a second slot of the second carrier.
3. The apparatus of claim 1 , wherein:
the first carrier has a first subcarrier spacing (SCS); and
the second carrier has a second SCS different than the first SCS.
4. The apparatus of claim 1 , wherein:
the first carrier is associated with a first cell; and
the second carrier is associated with a second cell different than the first cell.
5. The apparatus of claim 1 , wherein the one or more processor-readable instructions are further executable by the one or more processors individually or collectively to cause the apparatus to:
receive, via the first carrier, an acknowledgement from the UE for a packet on the second carrier, wherein the acknowledgement being received via the first carrier is based at least in part on the timing difference.
6. The apparatus of claim 1 , wherein the one or more processor-readable instructions are further executable by the one or more processors individually or collectively to cause the apparatus to:
transmit, to the UE, an indication of a minimum delay to observe between receiving a packet via the second carrier and reporting an acknowledgement for the packet via the first carrier.
7. The apparatus of claim 6 , wherein the one or more processor-readable instructions are further executable by the one or more processors individually or collectively to cause the apparatus to:
receive, from the UE, an indication of an updated timing difference; and
transmit, to the UE, an indication of an updated minimum delay to observe between receiving a subsequent packet via the second carrier and reporting an acknowledgement for the subsequent packet via the first carrier.
8. The apparatus of claim 6 , wherein the UE is configured to report the acknowledgement via a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH).
9. 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
one or more processor-readable instructions stored in the one or more memories and executable by the one or more processors individually or collectively to cause the apparatus to:
establish a first connection between the UE and a base station (BS) using a first carrier;
receive an indication that the UE is to establish a second connection for communications via a second carrier, wherein a timing difference exists between transmissions using the first carrier and transmissions using the second carrier; and
establish, after receiving the indication, the second connection in accordance with the timing difference.
10. The apparatus of claim 9 , wherein the timing difference is based at least in part on a timing offset between a first slot of the first carrier and a second slot of the second carrier.
11. The apparatus of claim 9 , wherein:
the first carrier has a first subcarrier spacing (SCS); and
the second carrier has a second SCS different than the first SCS.
12. The apparatus of claim 9 , wherein:
the first carrier is associated with a first cell; and
the second carrier is associated with a second cell different than the first cell.
13. The apparatus of claim 9 , wherein the one or more processor-readable instructions are further executable by the one or more processors individually or collectively to cause the apparatus to:
receive a packet via the second carrier; and
transmit an acknowledgement for the packet via the first carrier, wherein the acknowledgement being transmitted via the first carrier is based at least in part on the timing difference.
14. The apparatus of claim 9 , wherein the one or more processor-readable instructions are further executable by the one or more processors individually or collectively to cause the apparatus to:
receive, from the base station, an indication of a minimum delay to observe between receiving a packet via the second carrier and reporting an acknowledgement for the packet via the first carrier.
15. The apparatus of claim 14 , wherein the one or more processor-readable instructions are further executable by the one or more processors individually or collectively to cause the apparatus to:
transmit, to the base station, an indication of an updated timing difference; and
receive, from the base station, an indication of an updated minimum delay to observe between receiving a subsequent packet via the second carrier and reporting an acknowledgement for the subsequent packet via the first carrier.
16. The apparatus of claim 14 , wherein the UE is configured to report the acknowledgement via a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH).
17. A method for wireless communication at a base station (BS), comprising:
establishing a first connection between the BS and a user equipment (UE) using a first carrier, wherein a timing difference exists between transmissions using the first carrier and transmissions using a second carrier; and
transmitting an indication to the UE that the UE is to establish a second connection for communications via the second carrier, wherein the second connection is in accordance with the timing difference.
18. The method of claim 17 , wherein the timing difference is based at least in part on a timing offset between a first slot of the first carrier and a second slot of the second carrier.
19. The method of claim 17 , wherein:
the first carrier has a first subcarrier spacing (SCS); and
the second carrier has a second SCS different than the first SCS.
20. The method of claim 17 , wherein:
the first carrier is associated with a first cell; and
the second carrier is associated with a second cell different than the first cell.
21. The method of claim 17 , further comprising:
receiving, via the first carrier, an acknowledgement from the UE for a packet on the second carrier, wherein the acknowledgement being received via the first carrier is based at least in part on the timing difference.
22. The method of claim 17 , further comprising:
transmitting, to the UE, an indication of a minimum delay to observe between receiving a packet via the second carrier and reporting an acknowledgement for the packet via the first carrier.
23. The method of claim 22 , further comprising:
receiving, from the UE, an indication of an updated timing difference; and
transmitting, to the UE, an indication of an updated minimum delay to observe between receiving a subsequent packet via the second carrier and reporting an acknowledgement for the subsequent packet via the first carrier.
24. The method of claim 22 , wherein the UE is configured to report the acknowledgement via a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH).
25. A method for wireless communication at a user equipment (UE), comprising:
establishing a first connection between the UE and a base station (BS) using a first carrier;
receiving an indication that the UE is to establish a second connection for communications via a second carrier, wherein a timing difference exists between transmissions using the first carrier and transmissions using the second carrier; and
establishing, after receiving the indication, the second connection in accordance with the timing difference.
26. The method of claim 25 , wherein the timing difference is based at least in part on a timing offset between a first slot of the first carrier and a second slot of the second carrier.
27. The method of claim 25 , wherein:
the first carrier has a first subcarrier spacing (SCS); and
the second carrier has a second SCS different than the first SCS.
28. The method of claim 25 , wherein:
the first carrier is associated with a first cell; and
the second carrier is associated with a second cell different than the first cell.
29. The method of claim 25 , further comprising:
receiving a packet via the second carrier; and
transmitting an acknowledgement for the packet via the first carrier, wherein the acknowledgement being transmitted via the first carrier is based at least in part on the timing difference.
30. The method of claim 25 , further comprising:
receiving, from the base station, an indication of a minimum delay to observe between receiving a packet via the second carrier and reporting an acknowledgement for the packet via the first carrier.