Method and apparatus for transmission power control for a sounding reference signal

Abstract

A method and apparatus for transmitting a reference signal from a User Equipment (UE) are provided. The method includes transmitting a first reference signal using a sequence determined from an identity of the at least one transmission point and transmitting a second reference signal with a transmission power having an offset with a first maximum value configured by higher layer signaling from the at least one transmission point; and transmitting a first reference signal using a sequence configured to the UE by higher layer signaling from the at least one transmission point and transmitting a second reference signal with a transmission power having an offset with a second maximum value configured by higher layer signaling from the at least one transmission point, wherein the second maximum value is larger than the first maximum value, and the first reference signal and the second reference signal are either identical or non-identical.

What is claimed is: 
     
       1. A method for transmitting signals from a user equipment (UE) that receives signaling from at least one transmission point and transmits signaling to at least one reception point, the method comprising the steps of:
 transmitting a first reference signal using a sequence determined from an identity of the at least one transmission point; 
 transmitting a second reference signal with a first transmission power having an offset with a first maximum value configured using first higher layer signaling received from the at least one transmission point; 
 transmitting a third reference signal using a sequence configured to the UE using second higher layer signaling received from the at least one transmission point; and 
 transmitting a fourth reference signal with a second transmission power having an offset with a second maximum value configured using third higher layer signaling received from the at least one transmission point, 
 wherein the second maximum value is larger than the first maximum value. 
 
     
     
       2. The method of  claim 1 , wherein each of the first reference signal and the third reference signal is one of a demodulation reference signal that is associated with a physical uplink shared channel or with a physical uplink control channel, and a sounding reference signal, and
 wherein each of the second reference signal and the fourth reference signal is a sounding reference signal, and 
 wherein the transmission power offset of the second reference signal is relative to a transmission power of a signal, other than sounding reference signals, in the physical uplink shared channel. 
 
     
     
       3. The method of  claim 2 , wherein the sounding reference signal is transmitted periodically or dynamically. 
     
     
       4. The method of  claim 1 , further comprising:
 determining the first transmission power for the second reference signal by applying a first compensation factor to a first path loss estimate, the second reference signal including a sounding reference signal; and 
 determining the second transmission power for the fourth reference signal by applying a second compensation factor to a second path loss estimate, the fourth reference signal including a sounding reference signal. 
 
     
     
       5. The method of  claim 1 , wherein the sequence configured to the UE is a Zadoff-Chu sequence. 
     
     
       6. The method of  claim 1 , wherein at least one among the first reference signal, second reference signal, third reference signal, and fourth reference signal is a sounding reference signal, the transmission power of the sounding reference signal is adjusted by a transmission power control (TPC) command provided by a downlink control information (DCI) format that includes cyclic redundancy check (CRC) bits that are scrambled by a radio network temporary identifier (RNTI). 
     
     
       7. A method for transmitting signals from a user equipment (UE) in response to an indication by a field included in a downlink control information (DCI) format conveyed to the UE in a physical downlink control channel transmitted from at least one transmission point, the method comprising the steps of:
 transmitting a sounding reference signal with a first power determined from a first set of parameters, if the DCI format schedules data transmission to the UE; and 
 transmitting signals on a physical uplink shared channel with a second power determined from a second set of parameters, if the DCI format schedules data transmission from the UE. 
 
     
     
       8. The method of  claim 7 , wherein each of the first and second sets of parameters includes a power control command. 
     
     
       9. The method of  claim 7 , wherein each of the first and second sets of parameters includes a power offset. 
     
     
       10. The method of  claim 7 , wherein the sounding reference signal reports channel state information (CSI) of the UE. 
     
     
       11. A user equipment (UE) for transmitting signals, the UE receiving signaling from at least one transmission point and transmitting signaling to at least one reception point, the UE comprising:
 a receiver configured to receive higher layer signaling from the at least one transmission point; and 
 a transmitter configured to:
 transmit a first reference signal using a sequence determined from an identity of the at least one transmission point, 
 transmit a second reference signal with a first transmission power having an offset with a first maximum value configured using first higher layer signaling received from the at least one transmission point, 
 transmit a third reference signal using a sequence configured by second higher layer signaling received from the at least one transmission point, and 
 transmit a fourth reference signal with a second transmission power having an offset with a second maximum value configured using third higher layer signaling received from the at least one transmission point, 
 
 wherein the second maximum value is larger than the first maximum value. 
 
     
     
       12. The UE of  claim 11 , wherein each of the first reference signal and the third reference signal is one of a demodulation reference signal that is associated with a physical uplink shared channel or with a physical uplink control channel, and a sounding reference signal, and
 wherein each of the second reference signal and the fourth reference signal is a sounding reference signal and the transmission power offset of the second reference signal is relative to a transmission power of a signal, other than sounding reference signals, in the physical uplink shared channel. 
 
     
     
       13. The UE of  claim 12 , wherein the sounding reference signals are transmitted periodically or dynamically. 
     
     
       14. The UE of  claim 11 , further comprising:
 a controller configured to determine the first transmission power for the second reference signal by applying a first compensation factor to a first path loss estimate, and 
 to determine the second transmission power for the fourth reference signal by applying a second compensation factor to a second path loss estimate, the fourth reference signal including a sounding reference signal. 
 
     
     
       15. The UE of  claim 11 , wherein the sequence configured by the second higher layer signaling is a Zadoff-Chu sequence. 
     
     
       16. The UE of  claim 11 , wherein at least one among the first reference signal, second reference signal, third reference signal, and fourth reference signal is a sounding reference signal, the transmission power of the sounding reference signal is adjusted by a transmission power control (TPC) command provided by a downlink control information (DCI) format that includes cyclic redundancy check (CRC) bits that are scrambled by a radio network temporary identifier (RNTI). 
     
     
       17. A user equipment (UE) for transmitting signals in response to an indication by a field included in a downlink control information (DCI) format conveyed in a physical downlink control channel transmitted from at least one transmission point, the UE comprising:
 a receiver configured to receive DCI formats in respective physical downlink control channels; and 
 a transmitter configured to transmit a sounding reference signal with a first power determined from a first set of parameters, if a first DCI format from among the DCI formats schedules data transmission to the UE apparatus, and to transmit signals on a physical uplink shared channel with a second power determined from a second set of parameters, if a second DCI format from among the DCI formats schedules data transmission from the UE. 
 
     
     
       18. The UE of  claim 17 , wherein each of the first and second sets of parameters includes a power control command. 
     
     
       19. The UE of  claim 17 , wherein each of the first and second sets of parameters includes a power offset. 
     
     
       20. The UE of  claim 17 , wherein the sounding reference signal reports channel state information (CSI) of the UE. 
     
     
       21. A method for a user equipment (UE) to determine power for signal transmission, the method comprising:
 receiving information about a configuration for a first set of parameters associated with transmission of a sounding reference signal (SRS) and information about a configuration for a second set of parameters associated with transmission of a physical uplink shared channel (PUSCH);   receiving at least one of a first downlink control information (DCI) format associated with power control of the SRS transmission or a second DCI format associated with power control of the PUSCH transmission; and   performing a power control of the SRS transmission using the first set of parameters and a first transmission power control (TPC) command in the first DCI format, in case that the UE transmits the SRS; and   performing the power control of the PUSCH transmission using the second set of parameters and a second TPC command in the second DCI format, in case that the UE transmits the PUSCH.   
     
     
       22. The method of claim 21, wherein the first set of parameters includes use of a first path-loss and the second set of parameters includes use of a second path-loss. 
     
     
       23. The method of claim 21, wherein the first set of parameters includes use of one of a first open loop power setting, a first path-loss compensation factor, and a first closed-loop transmission power control (TPC) process, and
 wherein the second set of parameters includes use of one of a second open loop power setting, a second path-loss compensation factor, and a second closed-loop TPC process.   
     
     
       24. The method of claim 23, wherein the DCI format includes a TPC command value; and
 wherein the DCI format indicates whether the TPC command value is for one of the first closed-loop TPC process and the second closed-loop TPC process.   
     
     
       25. The method of claim 23, wherein receiving the DCI format comprises one of:
 receiving the DCI format having a cyclic redundancy check (CRC) field scrambled by a TPC-SRS-radio network temporary identifier (RNTI) and including a first TPC command value for the first closed-loop TPC process; and   receiving the DCI format having a CRC field scrambled by a TPC-PUSCH-RNTI and including a second TPC command value for the second closed-loop TPC process.   
     
     
       26. A user equipment (UE), comprising:
 a transceiver; and   a processor configured to:
 receive, through the transceiver, information about a configuration for a first set of parameters associated with transmission of a sounding reference signal (SRS) and information about a configuration for a second set of parameters associated with transmission of a physical uplink shared channel (PUSCH), 
 receive through the transceiver, a first downlink control information (DCI) format associated with power control of the SRS transmission or a second DCI format associated with power control of the PUSCH transmission, 
 perform the power control of the SRS transmission using the first set of parameters and a first transmission power control (TPC) command in the first DCI format, in case that the UE transmits the SRS, and 
 perform the power control of the PUSCH transmission using the second set of parameters and a second TPC command in the second DCI format, in case that the UE transmits the PUSCH. 
   
     
     
       27. The UE of claim 26, wherein the first set of parameters includes use of a first path-loss and the second set of parameters includes use of a second path-loss. 
     
     
       28. The UE of claim 26, wherein the first set of parameters includes use of one of a first open loop power setting, a first path-loss compensation factor, and a first closed-loop transmission power control (TPC) process, and
 wherein the second set of parameters includes use of one of a second open loop power setting, a second path-loss compensation factor, and a second closed-loop TPC process.   
     
     
       29. The UE of claim 28, wherein the DCI format includes a TPC command value; and
 wherein the DCI format indicates whether the TPC command value is for one of the first closed-loop TPC process and the second closed-loop TPC process.   
     
     
       30. The UE of claim 28, wherein the receiver is further configured to:
 receive a DCI format having a cyclic redundancy check (CRC) field scrambled by a TPC-SRS-radio network temporary identifier (RNTI) and including a first TPC command value for the first closed-loop TPC process; and   receive a DCI format having a CRC field scrambled by a TPC-PUSCH-RNTI and including a second TPC command value for the second closed-loop TPC process.   
     
     
       31. A base station, comprising:
 a transceiver; and   a processor configured to:   transmit, through the transceiver, information about a configuration for a first set of parameters associated with transmission of a sounding reference signal (SRS) and information about a configuration for a second set of parameters associated with transmission of a physical uplink shared channel (PUSCH),   transmit, through the transceiver, a first downlink control information (DCI) format associated with power control of the SRS or a second DCI format associated with power control of the PUSCH,   receive, through the transceiver, the SRS by using the first set of parameters and a first transmission power control (TPC) command in the first DCI format, in case that a user equipment (UE) transmits the SRS, and   receive, through the transceiver, the PUSCH by using the second set of parameters and a second TPC command in the second DCI format, in case that the UE transmits the PUSCH.   
     
     
       32. The base station of claim 31, wherein the first set of parameters includes use of a first path-loss and the second set of parameters includes use of a second path-loss. 
     
     
       33. The base station of claim 31, wherein the first set of parameters includes use of one of a first open loop power setting, a first path-loss compensation factor, and a first closed-loop transmission power control (TPC) process, and
 wherein the second set of parameters includes use of one of a second open loop power setting, a second path-loss compensation factor, and a second closed-loop TPC process.   
     
     
       34. The base station of claim 33, wherein the DCI format includes a TPC command value; and
 wherein the DCI format indicates whether the TPC command value is for one of the first closed-loop TPC process and the second closed-loop TPC process.   
     
     
       35. The base station of claim 33, wherein the processor is further configured to:
 transmit, through the transceiver, a DCI format having a cyclic redundancy check (CRC) field scrambled by a TPC-SRS-radio network temporary identifier (RNTI) and including a first TPC command value for the first closed-loop TPC process; and   transmit, through the transceiver, a DCI format having a CRC field scrambled by a TPC-PUSCH-RNTI and including a second TPC command value for the second closed-loop TPC process.   
     
     
       36. A method for a base station, the method comprising:
 transmitting information about a configuration for a first set of parameters associated with transmission of a sounding reference signal (SRS) and information about a configuration for a second set of parameters associated with transmission of a physical uplink shared channel (PUSCH);   transmitting a first downlink control information (DCI) format associated with a power control of the SRS or a second DCI format associated with a power control of the PUSCH;   receiving the SRS by using the first set of parameters and a first transmission power control (TPC) command in the first DCI format, in case that a user equipment (UE) transmits the SRS; and   receiving the PUSCH by using the second set of parameters and a second TPC command in the second DCI format, in case that the UE transmits the PUSCH.   
     
     
       37. The method of claim 36, wherein the first set of parameters includes use of a first path-loss and the second set of parameters includes use of a second path-loss. 
     
     
       38. The method of claim 36, wherein the first set of parameters includes use of one of a first open loop power setting, a first path-loss compensation factor, and a first closed-loop transmission power control (TPC) process, and
 wherein the second set of parameters includes use of one of a second open loop power setting, a second path-loss compensation factor, and a second closed-loop TPC process.   
     
     
       39. The method of claim 38, wherein the DCI format includes a TPC command value; and
 wherein the DCI format indicates whether the TPC command value is for one of the first closed-loop TPC process and the second closed-loop TPC process.   
     
     
       40. The method of claim 38, wherein transmitting the DCI format comprises one of:
 transmitting the DCI format having a cyclic redundancy check (CRC) field scrambled by a TPC-SRS-radio network temporary identifier (RNTI) and including a first TPC command value for the first closed-loop TPC process; and   transmitting the DCI format having a CRC field scrambled by a TPC-PUSCH-RNTI and including a second TPC command value for the second closed-loop TPC process.