Beam failure report
Systems, apparatuses, and methods are described for wireless communications. A wireless device configured to communicate via beams of one or more cells may report a beam failure using a media access control (MAC) control element (CE) (e.g., a power headroom report (PHR) MAC CE). The MAC CE may also be used to report other information for one or more cells with which the wireless device is associated. Beam failure reporting with a MAC CE may be combined with other beam failure procedures.
1. A method comprising:
receiving, by a wireless device from a base station, at least one message comprising configuration parameters of at least one cell;
determining beam failure for a plurality of cells; and
transmitting, based on the beam failure for the plurality of cells, at least one medium access control (MAC) control element (CE) comprising:
a plurality of first fields, wherein each first field of the plurality of first fields is associated with a cell of the plurality of cells and indicates a presence of a second field, of a plurality of second fields, for that cell; and
the plurality of second fields, wherein each second field of the plurality of second fields is associated with beam failure for a cell of the plurality of cells.
2. The method of claim 1 , wherein the beam failure for the plurality of cells is associated with at least one downlink control channel of the plurality of cells.
3. The method of claim 1 , wherein the at least one MAC CE is associated with at least one of:
reporting beam failure;
a beam failure indication;
a power backoff;
a real transmission;
a reference format;
a power headroom report (PHR); or
a transmit power.
4. The method of claim 1 , wherein the transmitting the at least one MAC CE comprises transmitting the at least one MAC CE via a second cell.
5. The method of claim 1 , wherein the plurality of second fields comprises beam information associated with the beam failure for the plurality of cells.
6. The method of claim 1 , wherein the at least one message comprises beam configuration parameters indicating at least one of:
configuration of at least one reference signal for beam failure recovery;
a first threshold for beam failure recovery;
a second threshold for beam failure recovery;
at least one random access resource for beam failure recovery; or
association between each of the at least one random access resource and the at least one reference signal.
7. The method of claim 1 , further comprising based on the beam failure for the plurality of cells:
transmitting, via a second cell, at least one preamble associated with beam failure recovery; and
monitoring a downlink control channel for a response to the at least one preamble; and
wherein the transmitting the at least one MAC CE comprises transmitting the at least one MAC CE after determining that the response has not been received.
8. The method of claim 1 , wherein the at least one MAC CE further comprises:
at least one third field, associated with a second cell, that indicates lack of presence of at least one fourth field for the second cell.
9. A method comprising:
determining, by a wireless device configured to receive downlink communications, beam failure for a plurality of cells;
transmitting, based on the beam failure for the plurality of cells, at least one medium access control (MAC) control element (CE) comprising:
a plurality of first fields, wherein each first field of the plurality of first fields is associated with a cell of the plurality of cells and indicates a presence of a second field, of a plurality of second fields, for that cell; and
the plurality of second fields, wherein each second field of the plurality of second fields is associated with beam failure for a cell of the plurality of cells;
transmitting, via at least one cell and based on at least one beam failure, at least one preamble; and
monitoring a downlink control channel for a response to the at least one preamble.
10. The method of claim 9 , wherein the transmitting the at least one MAC CE comprises transmitting the at least one MAC CE after determining the response has not been received.
11. The method of claim 9 , wherein the at least one MAC CE is associated with at least one of:
reporting beam failure;
a beam failure indication;
a power backoff;
a real transmission;
a reference format;
a power headroom report (PHR); or
a transmit power.
12. The method of claim 9 , wherein the transmitting the at least one MAC CE comprises transmitting the at least one MAC CE via a second cell.
13. The method of claim 9 , wherein the at least one MAC CE further comprises:
a third field, associated with a second cell, that indicates lack of presence of a fourth field for the second cell.
14. A method comprising:
determining, by a wireless device configured to receive downlink communications, beam failure for a plurality of cells; and
transmitting, based on the beam failure for the plurality of cells, at least one medium access control (MAC) control element (CE) comprising:
a plurality of first fields, wherein each first field of the plurality of first fields is associated with a cell of the plurality of cells and indicates a presence of a second field, of a plurality of second fields, for that cell; and
the plurality of second fields, wherein each second field of the plurality of second fields is associated with beam failure for a cell of the plurality of cells.
15. The method of claim 14 , wherein the beam failure for the plurality of cells is associated with at least one downlink control channel of the plurality of cells.
16. The method of claim 14 , wherein the at least one MAC CE is associated with at least one of:
reporting beam failure;
a beam failure indication;
a power backoff;
a real transmission;
a reference format;
a power headroom report (PHR); or
a transmit power.
17. The method of claim 14 , wherein the at least one MAC CE further comprises:
a third field, associated with a second cell, that indicates lack of presence of a fourth field for the second cell.
18. The method of claim 14 , wherein at least one cell of the plurality of cells is configured as a downlink-only cell for the wireless device.