Simultaneous transmission in multiple timing advance groups

Abstract

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.

What is claimed is: 
     
         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;   identifying a Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), or Sounding Reference Symbol (SRS) transmission for a second serving cell other than the first serving cell;   transmitting a PRACH transmission to the first serving cell in a subframe; and   transmitting the PUCCH, PUSCH, or SRS transmission to the second serving cell in the same subframe.   
     
     
         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, PUSCH, or SRS transmission does not exceed a maximum transmission power for the user equipment.   
     
     
         3 . The method of  claim 1 , further comprising:
 scaling down a PUCCH, PUSCH, or SRS transmission power level during the subframe so that a combined transmission power level for the PRACH transmission and the PUCCH, PUSCH, or SRS 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 PUSCH, PUSCH, or SRS.   
     
     
         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; 
 identify a Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), or Sounding Reference Symbol (SRS) transmission for a second serving cell other than the first serving cell; 
 generate a PRACH transmission for the first serving cell in a subframe; and 
 generate the PUCCH, PUSCH, or SRS transmission for the second serving cell in the same subframe; and 
   a modem configured to transmit the PUCCH, PUSCH, or SRS transmission to one or more base stations.   
     
     
         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 or PUSCH or SRS 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:
 scale down a PUCCH, PUSCH, or SRS transmission power level during the subframe so that a combined transmission power level for the PRACH transmission and the PUCCH, PUSCH, or SRS 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 PUSCH, PUSCH, or SRS when a combined transmission of PRACH and PUCCH, PUSCH, or SRS 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.   
     
     
         17 . A method comprising:
 performing by one or more processors in user equipment,   identifying a first transmission for a first serving cell during a subframe;   identifying a second transmission for a second serving cell during the subframe;   identifying a transmission time difference between the first transmission and the second transmission within the subframe; and   scaling transmission power levels for the first transmission or the second transmission or both prior to a start of the subframe so that a combined transmission power level for the first transmission and the second transmission does not exceed a maximum transmission power for the user equipment.   
     
     
         18 . The method of  claim 17 , wherein a constant transmission power is assigned to all symbols in the first and second transmissions. 
     
     
         19 . The method of  claim 17 , wherein the first and second transmissions are selected from one or more of:
 a Physical Uplink Control Channel (PUCCH) transmission;   a Physical Uplink Shared Channel (PUSCH) transmission;   a Physical Random Access Channel (PRACH) transmission; and   a Sounding Reference Symbol (SRS) transmission.   
     
     
         20 . A user equipment device, comprising:
 a processor configured to:
 identify a first transmission for a first serving cell during a subframe; 
 identify a second transmission for a second serving cell during the subframe; 
 identify a transmission time difference between the first transmission and the second transmission within the subframe; and 
 scale transmission power levels for the first transmission or the second transmission or both prior to a start of the subframe so that a combined transmission power level for the first transmission and the second transmission does not exceed a maximum transmission power for the user equipment; and 
   a modem configured to transmit the first and second transmissions to one or more base stations.   
     
     
         21 . The user equipment device of  claim 20 , wherein a constant transmission power is assigned to all symbols in the first and second transmissions. 
     
     
         22 . The user equipment device of  claim 20 , wherein the first and second transmissions are selected from one or more of:
 a Physical Uplink Control Channel (PUCCH) transmission;   a Physical Uplink Shared Channel (PUSCH) transmission;   a Physical Random Access Channel (PRACH) transmission; and   a Sounding Reference Symbol (SRS) transmission.