Power headroom transmission for a triggered grant
A wireless device receives, in a first subframe, a first DCI comprising: a first field indicating an assignment of resource blocks for transmissions via an uplink subframe; and a first trigger indicating that the first DCI is triggered in response to a second DCI. A power headroom value of a reference subframe for transmission via the resource blocks of the uplink subframe are determined. The reference subframe is later than the first subframe and earlier than the uplink subframe. A power headroom value of the reference subframe is transmitted via the uplink subframe.
1. A method comprising:
receiving, by a wireless device and in a first subframe, an uplink grant triggered in response to receiving a trigger during a validation duration, the uplink grant
indicating resource blocks;
determining a power headroom value of a reference subframe, the reference subframe being later than the first subframe; and
receiving, during the validation duration, the trigger indicating an uplink subframe for transmission of the power headroom value, the uplink subframe being later than the reference subframe; and
transmitting, via the uplink subframe and using the resource blocks, the power headroom value of the reference subframe.
2. The method of claim 1 , further comprising receiving, by the wireless device, at least one message comprising configuration parameters of a plurality of cells comprising a licensed assisted access (LAA) cell, wherein the configuration parameters comprise at least one power headroom configuration parameter and the uplink subframe is an uplink subframe of the LAA cell.
3. The method of claim 1 , further comprising restarting a power headroom timer in response to receiving a first DCI comprising the uplink grant.
4. The method of claim 1 , further comprising restarting, in the reference subframe, a power headroom timer.
5. The method of claim 1 , wherein:
the trigger is received in a second DCI that is received via a common search space of a control channel of a licensed assisted access (LAA) cell;
the second DCI corresponds to a pre-defined radio network temporary identifier (RNTI); and
the uplink subframe is an uplink subframe of the LAA cell.
6. The method of claim 1 , wherein the power headroom value comprises one or more of:
a Type 1 power headroom value; and
a Type 2 power headroom value.
7. The method of claim 1 , wherein:
the reference subframe is a predetermined number of subframes later than the first subframe; and
the predetermined number is four.
8. The method of claim 1 , wherein the trigger is received in a second DCI that comprises:
a subframe format field indicating a subframe format; and
a subframe field indicating a subframe offset.
9. The method of claim 1 , wherein the trigger is received in a second DCI that is received via a common search space of a downlink control channel.
10. The method of claim 1 , wherein:
the power headroom value comprises a first power headroom value of a first cell;
the first power headroom value is determined assuming that at least one transport block is transmitted in the reference subframe, if the wireless device receives a first trigger on or before the first subframe indicating transmission of the at least one transport block in the reference subframe; and
the first power headroom value is determined assuming that at least one transport block is not transmitted in the reference subframe, if the wireless device receives a first trigger after the first subframe indicating transmission of the at least one transport block in the reference subframe.
11. A wireless device comprising:
one or more processors;
memory storing instructions that, when executed by the one or more processors, cause the wireless device to:
receiving, in a first subframe, an uplink grant triggered in response to receiving a trigger during a validation duration, the uplink grant
indicating resource blocks;
determine a power headroom value of a reference subframe, the reference subframe being later than the first subframe; and
receive, during the validation duration, the trigger indicating an uplink subframe for transmission of the power headroom value, the uplink subframe being later than the reference subframe; and
transmit, via the uplink subframe and using the resource blocks, the power headroom value of the reference subframe.
12. The wireless device of claim 11 , wherein the instructions, when executed by the one or more processors, cause the wireless device to receive at least one message comprising configuration parameters of a plurality of cells comprising a licensed assisted access (LAA) cell, wherein the configuration parameters comprise at least one power headroom configuration parameter and the uplink subframe is an uplink subframe of the LAA cell.
13. The wireless device of claim 11 , wherein the instructions, when executed by the one or more processors, cause the wireless device to restart a power headroom timer in response to receiving a first DCI comprising the uplink grant.
14. The wireless device of claim 11 , wherein the instructions, when executed by the one or more processors, cause the wireless device to restart, in the reference subframe, a power headroom timer.
15. The wireless device of claim 11 , wherein:
the trigger is received in a second DCI that is received via a common search space of a control channel of a licensed assisted access (LAA) cell;
the second DCI corresponds to a pre-defined radio network temporary identifier (RNTI); and
the uplink subframe is an uplink subframe of the LAA cell.
16. The wireless device of claim 11 , wherein the power headroom value comprises one or more of:
a Type 1 power headroom value; and
a Type 2 power headroom value.
17. The wireless device of claim 11 , wherein:
the reference subframe is a predetermined number of subframes later than the first subframe; and
the predetermined number is four.
18. The wireless device of claim 11 , wherein the trigger is received in a second DCI that comprises:
a subframe format field indicating a subframe format; and
a subframe field indicating a subframe offset.
19. The wireless device of claim 11 , wherein the second DCI is received via a common search space of a downlink control channel.
20. The wireless device of claim 11 , wherein:
the power headroom value comprises a first power headroom value of a first cell;
the first power headroom value is determined assuming that at least one transport block is transmitted in the reference subframe, if the wireless device receives a first trigger on or before the first subframe indicating transmission of the at least one transport block in the reference subframe; and
the first power headroom value is determined assuming that at least one transport block is not transmitted in the reference subframe, if the wireless device receives a first trigger after the first subframe indicating transmission of the at least one transport block in the reference subframe.