Beam failure recovery method and device and communication system

1. A beam failure recovery device configured to operate a terminal equipment, the beam failure recovery device comprising:

a memory; and

processor circuitry coupled to the memory and configured to:

upon the terminal equipment receive a beam failure recovery (BFR) response, and after a period of time, monitor a downlink signal(s) in a first cell(s) of the terminal equipment according to an antenna quasi-co-located (QCL) parameter identical to a selected reference signal(s) (q_new) or a reference signal(s) (q_new) indicated by a higher layer,

wherein the period of time is a number of symbols associated with a subcarrier spacing, and

wherein the subcarrier spacing is according to:

a subcarrier spacing of one of the first cell(s) for the reception of the downlink signal(s).

2. The beam failure recovery device according to claim 1 , wherein,

the downlink signal comprises at least one of the following:

a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), a channel state information reference signal (CSI-RS), and a synchronization signal block (SSB).

3. The beam failure recovery device according to claim 2 , wherein,

in a case where there exists an occasion for monitoring the physical downlink control channel (PDCCH) in the first cell, the receiver monitors the physical downlink control channel (PDCCH) in the first cell.

4. The beam failure recovery device according to claim 2 , wherein,

the physical downlink shared channel (PDSCH) comprises:

a physical downlink shared channel (PDSCH) in the first cell; or

in a case where there exists an occasion for monitoring the physical downlink control channel (PDCCH) in the first cell, a physical downlink shared channel (PDSCH) scheduled by the monitored physical downlink control channel (PDCCH); or

a physical downlink shared channel (PDSCH) scheduled by a physical downlink control channel (PDCCH) receiving the beam failure recovery (BFR) response.

5. The beam failure recovery device according to claim 1 , wherein,

the beam failure recovery (BFR) response has a downlink control signaling (DCI) format scrambled by a cell radio network temporary identifier (C-RNTI) or modulation and coding scheme cell radio network temporary identifier (MCS-C-RNTI) cyclic redundancy check.

6. The beam failure recovery device according to claim 1 , wherein,

the beam failure recovery (BFR) response is detected in a search space of a beam failure recovery random access response (BFR RAR).

7. The beam failure recovery device according to claim 6 , wherein,

the beam failure recovery (BFR) response is a first physical downlink control channel (PDCCH) in the search space.

8. The beam failure recovery device according to claim 1 , wherein,

a starting point (T 1 ) of the period of time is:

a slot receiving the beam failure recovery (BFR) response; or

a last symbol of the beam failure recovery (BFR) response; or

a last symbol in a control resource set receiving the beam failure recovery (BFR) response.

9. The beam failure recovery device according to claim 1 , wherein,

an ending point (T 2 ) of the period of time is:

a slot used for receiving the downlink signal; or

a first symbol in a control resource set (CORESET) or a search space used for monitoring the downlink signal; or

a first symbol of the downlink signal.

10. The beam failure recovery device according to claim 1 , wherein the downlink signal comprises a physical downlink control channel (PDCCH), and the control resource set (CORESET) or the search space used for monitoring the downlink signal satisfies at least one of the following conditions:

all control resource sets (CORESETs) or search spaces on an active bandwidth part (BWP) in the first cell to which the physical downlink control channel (PDCCH) corresponds;

that the control resource sets (CORESETs) or search spaces to which the physical downlink control channel (PDCCH) corresponds are default control resource sets (CORESETs) or search spaces; and

that the control resource sets (CORESETs) or search spaces to which the physical downlink control channel (PDCCH) corresponds are control resource sets (CORESETs) or search spaces indicated via radio resource control (RRC) signaling.

11. The beam failure recovery device according to claim 1 , wherein,

the activation or reconfiguration signaling comprises:

activation or reconfiguration signaling for the first cell; or

activation or reconfiguration signaling for a second cell associated with the first cell; or

activation or reconfiguration signaling for a primary cell of the terminal equipment.

12. The beam failure recovery device according to claim 1 , wherein,

the activation or reconfiguration signaling comprises:

MAC-CE signaling for activating a TCI state of a control resource set (CORESET) to which the downlink signal corresponds; or

MAC-CE signaling for activating a TCI state set to which the downlink signal corresponds; or

radio resource control (RRC) signaling for reconfiguring a TCI state set of a control resource set (CORESET) to which the downlink signal corresponds; or

radio resource control (RRC) signaling for reconfiguring a TCI state set to which the downlink signal corresponds.

13. The beam failure recovery device according to claim 1 , wherein,

the first cell comprises:

a cell(s) where beam failure is detected, and to which cell ID(s) reported by the terminal equipment to the network device corresponds.

14. The beam failure recovery device according to claim 1 , wherein,

the reference signal indicated by the higher layer is a reference signal (q_new) indicated by the higher layer most recently.