Simultaneous transmission in multiple timing advance groups
Systems and methods for specifying UE power control allocation for simultaneous transmission of PRACH in a secondary serving cell and PUCCH/PUSCH/SRS in a different serving cell in another timing advance group are disclosed. Rules are provided for prioritizing transmission of PRACH and/or other UL channels/signals. Additionally, UE power allocation is controlled for misaligned subframes across different timing advance groups. Latency of UL synchronization for a secondary serving cell is reduced by prioritizing PRACH retransmission.
1. A method comprising:
performing by one or more processors in a user equipment device,
receiving a Physical Downlink Control Channel (PDCCH) order to initiate a random access procedure on a first serving cell that belongs to a first timing advance group;
identifying a Physical Uplink Control Channel (PUCCH) transmission for a second serving cell other than the first serving cell, the second serving cell belonging to a second timing advance group different than the first timing advance group, wherein if a channel state information (CSI) report is scheduled for the PUCCH transmission, and there is no HARQ-ACK feedback in the same subframe as a Physical Random Access Channel (PRACH) transmission on the first serving cell, the CSI report is dropped and the PRACH transmission is transmitted;
transmitting a PRACH transmission to the first serving cell in a subframe;
transmitting the PUCCH transmission to the second serving cell in the same subframe when the CSI report is not dropped; and
adjusting a transmission power of the PUCCH transmission to prioritize the PRACH transmission over the PUCCH transmission.
2. The method of claim 1 , further comprising:
scaling a transmission power level during the subframe so that a combined transmission power level for the PRACH transmission and the PUCCH transmission does not exceed a maximum transmission power for the user equipment.
3. The method of claim 1 , further comprising:
adjusting the transmission power of the PUCCH transmission during the subframe so that a combined transmission power for the PRACH transmission and the PUCCH transmission does not exceed a maximum transmission power for the user equipment.
4. The method of claim 3 , wherein:
said scaling down results in a PRACH transmission and no transmission of a PUCCH.
5. The method of claim 1 , further comprising:
determining that the PRACH transmission will be retransmitted in a second subframe; and
increasing a power level of the PRACH transmission during the second subframe.
6. The method of claim 1 , further comprising:
determining that the PRACH transmission will be retransmitted in a second subframe;
identifying one or more other uplink transmissions during the second subframe; and
increasing a transmission priority value for the PRACH transmission during the second subframe.
7. The method of claim 1 , further comprising:
determining that the PRACH transmission will be retransmitted in a second subframe;
identifying one or more other uplink transmissions during the second subframe; and
increasing a power level of the PRACH transmission during the second subframe.
8. The method of claim 1 , further comprising:
determining that the PRACH transmission will be retransmitted in a second subframe;
identifying one or more other uplink transmissions during the second subframe;
increasing a transmission priority value for the PRACH transmission during the second subframe; and
increasing a power level of the PRACH transmission during the second subframe.
9. A user equipment device, comprising:
a processor configured to:
identify a Physical Downlink Control Channel (PDCCH) order to initiate a random access procedure on a first serving cell that belongs to a first timing advance group;
identify a Physical Uplink Control Channel (PUCCH) transmission for a second serving cell other than the first serving cell, the second serving cell belonging to a second timing advance group different than the first timing advance group, wherein if a channel state information (CSI) report is scheduled for the PUCCH transmission, and there is no HARQ-ACK feedback in the same subframe as a Physical Random Access Channel (PRACH) transmission on the first serving cell, the CSI report is dropped and the PRACH transmission is transmitted;
generate a PRACH transmission for the first serving cell in a subframe; and
generate the PUCCH transmission for the second serving cell in the same subframe when the CSI report is not dropped; and
a modem configured to, when the CSI report is not dropped, transmit the PUCCH and PRACH transmissions to one or more base stations, and to adjust a transmission power of the PUCCH transmission to prioritize the PRACH transmission over the PUCCH transmission.
10. The user equipment device of claim 9 , the processor further configured to:
scale a transmission power level during the subframe so that a combined transmission power level for the PRACH transmission and the PUCCH transmission does not exceed a maximum transmission power for the user equipment.
11. The user equipment device of claim 9 , the processor further configured to:
adjust the transmission power of the PUCCH transmission during the subframe so that a combined transmission power for the PRACH transmission and the PUCCH transmission does not exceed a maximum transmission power for the user equipment.
12. The user equipment device of claim 11 , wherein:
the scaling down results in no transmission of a PUCCH when a combined transmission of PRACH and PUCCH would exceed a maximum transmission power for the user equipment.
13. The user equipment device of claim 9 , the processor further configured to:
determine that the PRACH transmission will be retransmitted in a second subframe; and
increase a power level of the PRACH transmission during the second subframe.
14. The user equipment device of claim 9 , the processor further configured to:
determine that the PRACH transmission will be retransmitted in a second subframe;
identify one or more other uplink transmissions during the second subframe; and
increase a transmission priority value for the PRACH transmission during the second subframe.
15. The user equipment device of claim 9 , the processor further configured to:
determine that the PRACH transmission will be retransmitted in a second subframe;
identify one or more other uplink transmissions during the second subframe; and
increase a power level of the PRACH transmission during the second subframe.
16. The user equipment device of claim 9 , the processor further configured to:
determine that the PRACH transmission will be retransmitted in a second subframe;
identify one or more other uplink transmissions during the second subframe;
increase a transmission priority value for the PRACH transmission during the second subframe; and
increase a power level of the PRACH transmission during the second subframe.