Methods and systems for beam recovery and management
A system and methods for beam failure recovery and management for multi-carrier communications with beamforming are disclosed herein. A wireless transmit/receive unit (WTRU) may monitor for and detect a beam failure of a beam associated with a secondary cell (Scell). The WTRU may select an Scell candidate beam. The WTRU may transmit using a selected uplink (UL) resource in a primary cell (SpCell) a medium access control (MAC) control element (CE) including an indication of Scell beam failure and identifying the selected candidate beam. The WTRU may receive an Scell beam failure indication response on the SpCell indicating an SCell index and a downlink (DL) quasi co-location (QCL) reference associated with the Scell. The WTRU may verify that the DL QCL reference matches with the candidate beam. The WTRU may perform random access on the SCell using the selected QCL reference and the selected candidate beam.
1. A wireless transmit/receive unit (WTRU) comprising a processor and memory, the processor and memory configured to:
receive configuration information, wherein the configuration information comprises an indication of one or more reference signals for beam management measurements and the configuration information comprises beam recovery configuration information, the beam recovery configuration information indicating one or more candidate beams for beam failure recovery and a respective uplink resource for each of the one or more candidate beams;
determine that beam failure has occurred based on the beam management measurements performed on the one or more reference signals, the one or more reference signals being associated with a beam used for monitoring a physical downlink control channel (PDCCH);
select a candidate beam of the one or more candidate beams for indicating the beam failure;
transmit an uplink transmission on the respective uplink resource associated with the selected candidate beam indicated by the beam recovery configuration information, and
receive a response to the uplink transmission, the response being received via a search space configured for beam failure recovery.
2. The WTRU of claim 1 , wherein the uplink resource associated with the selected candidate beam comprises a dedicated preamble.
3. The WTRU of claim 2 , wherein the processor and memory being configured to transmit the uplink transmission on the uplink resource associated with the selected candidate beam comprises the processor and memory being configured to transmit the dedicated preamble associated with the selected candidate beam using a time and frequency resource associated with the selected candidate beam.
4. The WTRU of claim 1 , wherein the one or more reference signals comprise one or more of a synchronization signal block or a channel state information reference signal (CSI-RS).
5. The WTRU of claim 1 , wherein the response comprises downlink control information, and the response indicates an identity of the WTRU.
6. The WTRU of claim 1 , wherein the processor and memory are further configured to:
receive a first search space for monitoring for physical downlink control channel (PDCCH) transmissions associated with a first transmission beam, the first transmission beam being associated with a first reference signal configuration; and
receive a second search space for monitoring for PDCCH transmissions associated with a second transmission beam, the second transmission beam being associated with a second reference signal configuration.
7. The WTRU of claim 1 , wherein the response comprises a random access response.
8. The WTRU of claim 1 , wherein the beam recovery configuration information indicates the search space configured for beam failure recovery.
9. The WTRU of claim 1 , wherein the response is received via the selected candidate beam.
10. The WTRU of claim 1 , wherein the beam recovery configuration information indicates an associated synchronization signal block (SSB) or associated channel state information reference signal (CSI-RS) for each of the one or more candidate beams.
11. A method implemented by a wireless transmit/receive unit (WTRU), the method comprising:
receiving configuration information, wherein the configuration information comprises an indication of one or more reference signals (RSs) for beam management measurements, and the configuration information comprises beam recovery configuration information, the beam recovery configuration information indicating one or more candidate beams for beam failure recovery and a respective uplink resource for each of the one or more candidate beams;
determining that beam failure has occurred based on the beam management measurements performed on the one or more reference signals, the one or more reference signals being associated with a beam used for monitoring a physical downlink control channel (PDCCH);
selecting a candidate beam of the one or more candidate beams for indicating the beam failure recovery;
transmitting an uplink transmission on the respective uplink resource associated with the selected candidate beam indicated by the beam recovery configuration information; and
receiving a response to the uplink transmission, the response being received via a search space configured for beam failure recovery.
12. The method of claim 11 , wherein the uplink resource associated with the selected candidate beams comprises a dedicated preamble.
13. The method of claim 12 , wherein the processor and memory being configured to transmit the uplink transmission on the uplink resource associated with the selected candidate beam comprises the processor and memory being configured to transmit the dedicated preamble associated with the selected candidate beam using a time and frequency resource associated with the selected candidate beam.
14. The method of claim 11 , wherein the one or more reference signals comprise one or more of a synchronization signal block or a channel state information reference signal (CSI-RS).
15. The method of claim 11 , wherein the response comprises downlink control information, and the response indicates an identity of the WTRU.
16. The method of claim 11 , wherein the processor and memory are further configured to:
receive a first search space for monitoring for physical downlink control channel (PDCCH) transmissions associated with a first transmission beam, the first transmission beam being associated with a first reference signal configuration; and
receive a second search space for monitoring for PDCCH transmissions associated with a second transmission beam, the second transmission beam being associated with a second reference signal configuration.
17. The method of claim 11 , wherein the response comprises a random access response.
18. The method of claim 11 , wherein the beam recovery configuration information indicates the search space configured for beam recovery.
19. The method of claim 1 , wherein the response is received via the selected candidate beam.
20. The method of claim 11 , wherein the beam recovery configuration information indicates an associated synchronization signal block (SSB) or an associated channel state information reference signal (CSI-RS) for each of the one or more candidate beams.