Transmission of sounding reference signals in communication systems with carrier aggregation
A base station triggers transmission of sounding reference signals (SRS) from one or multiple user equipments (UEs) on one or multiple cells and a UE determines a power, a time instance, and other parameters for SRS transmissions in response to the triggering. An SRS transmission can be on a cell where a UE is not configured to transmit data or control information.
1. A user equipment (UE), comprising
a transceiver configured to receive a configuration for a location of first bits in a downlink control information (DCI) format, the DCI format comprising one or more blocks of bits including the first bits, wherein each of the one or more blocks of bits comprises
one or more bits for a transmit power control (TPC) command, and
zero or more bits for a request for transmission of a sounding reference signal (SRS); and
a processor operably coupled to the transceiver, the processor configured to control an SRS transmission power based on a value of the one or more bits for the TPC command from the first bits and, when the first bits include one or more bits for the SRS request, a value of the one or more bits for the SRS request,
wherein the TPC command is used to control only the transmission power of the SRS,
wherein the transceiver is further configured to transmit the SRS, and
wherein:
a power of the SRS transmission on a serving cell is determined to be a smaller value among a first value and a second value,
the first value is a maximum transmission power, and
the second value is determined based on power control parameters comprising a bandwidth for the SRS transmission on the serving cell, a path loss value measured on the serving cell, a transmission power control adjustment state on the serving cell determined from the TPC command, and higher layer parameters for the serving cell.
2. The UE of claim 1 , wherein:
a number of the one or more blocks of bits is more than one,
each of the more than one blocks of bits corresponds to a serving cell, and
each of the more than one blocks of bits comprises either TPC command bits or both TPC command bits and SRS request bits for the serving cell.
3. The UE of claim 2 , wherein the UE is not configured for a physical uplink shared channel (PUSCH) transmission and physical uplink control channel (PUCCH) transmission on a serving cell.
4. The UE of claim 1 , wherein:
the transceiver is further configured to receive a configuration for a TPC-SRS-radio network temporary identifier (TPC-SRS-RNTI), and
a cyclic redundancy check (CRC) of the DCI format is scrambled by the TPC-SRS-RNTI.
5. The UE of claim 1 , wherein the zero or more bits for the SRS request are consecutive to the one or more bits for the TPC command in the DCI format.
6. The UE of claim 1 , wherein the processor is further configured to control the SRS transmission power on a cell based on:
a reference reception power for a physical uplink shared channel (PUSCH) transmission on the cell, when provided, and
a reference reception power for the SRS transmission on the cell, when a reference reception power for a PUSCH transmission on the cell is not provided.
7. The UE of claim 1 , wherein the transmission power P SRS,c (i) of the SRS in decibels per milliwatt (dBm) in time instance i and on a serving cell c is determined as:
P SRS,c (i)=min{P CMAX,c (i), 10log 10 (M SRS,c )+P O_SRS,c +α SRS,c ·PL c +f c (i)} dBm,
where:
min{x, y} is a minimum function resulting in a smaller of numbers x, y,
log 10 (x) is a logarithm function with base 10 resulting a logarithm with base 10 for number x,
P CMAX,c (i) is the maximum transmission power in time instance i configured by higher layers for the serving cell c,
M SRS,c is the bandwidth for the transmission of the SRS in time instance i and on the serving cell c,
P O_SRS,c is configured by higher layers for the serving cell c, m=0 when the transmission of the SRS is configured by higher layers, and m=1 when the SRS transmission is configured by the DCI format,
α SRS,c is configured by higher layers for the SRS on the serving cell c,
PL c is a path loss value measured on the serving cell c, and
f c (i) is a transmission power control adjustment state, determined from the TPC command in the DCI format, for SRS transmission in time instance i and on the serving cell c.
8. The UE of claim 7 , wherein a power headroom (PH) for the transmission of the SRS in time instance i and on the serving cell c is determined based on:
PH c (i)=P CMAX,c (i)−{10 log 10 (M SRS,c (i))+P O SCS,c (m)+α SRS,c ·PL c +f c (i)}.
9. The UE of claim 7 , wherein:
f c (0)=ΔP rampup,c ,
ΔP rampup,c =min[{max(0, P CMAX,c −(10 log 10 (M SRS,c )+P O_SRS,c (m)+α SRS,c ·PL c ))}, ΔP rampuprequested,c ],
max{x, y} is a maximum function resulting the larger of numbers x, y,
where:
M SRS,c is the bandwidth for the transmission of the SRS at a time instance of a first SRS transmission on the serving cell c, and
ΔP rampuprequested,c is a total power ramp-up power from a first to a last random access preamble transmission on the serving cell c and is configured by higher layers.
10. A method, comprising:
receiving a configuration for a location of first bits in a downlink control information (DCI) format, the DCI format comprising one or more blocks of bits including the first bits, wherein each of the one or more blocks of bits comprises
one or more bits a transmit power control (TPC) command, and
zero of more bits for a request for transmission of a sounding reference signal (SRS);
controlling an SRS transmission power based on a value of the one or more bits for the TPC command from the first bits and, when the first bits include one or more bits for the SRS request, a value of the one or more bits for the SRS request, wherein the TPC command is used to control only the transmission power of the SRS; and
transmitting the SRS, wherein:
a power of the SRS transmission on a serving cell is determined to be a smaller value among a first value and a second value,
the first value is a maximum transmission power, and
the second value is determined based on power control parameters comprising a bandwidth for the SRS transmission on the serving cell, a path loss value measured on the serving cell, a transmission power control adjustment state on the serving cell determined from the TPC command, and higher layer parameters for the serving cell.
11. The method of claim 10 , wherein:
a number of the one or more blocks of bits is more than one,
each of the more than one blocks of bits corresponds to a serving cell, and
each of the more than one blocks of bits comprises either TPC command bits or both TPC command bits and SRS request bits for the serving cell.
12. The method of claim 11 , further comprising:
not transmitting a physical uplink shared channel (PUSCH) and physical uplink control channel (PUCCH) on a serving cell.
13. The method of claim 10 , further comprising:
receiving a configuration for a TPC-SRS-radio network temporary identifier (TPC-SRS-RNTI),
wherein a cyclic redundancy check (CRC) of the DCI formation is scrambled by the TPC-SRS-RNTI.
14. The method of claim 10 , wherein the zero or more bits for the SRS request are consecutive to the one or more bits for the TPC command in the DCI format.
15. The method of claim 10 , further comprising:
controlling the SRS transmission power on a cell based on:
a reference reception power for a physical uplink shared channel (PUSCH) transmission on the cell, when provided, and
a reference reception power for the SRS transmission on the cell, when a reference reception power for a PUSCH transmission on the cell is not provided.
16. The method of claim 10 , wherein the transmission power P SRS,c (i) of the SRS in decibels per milliwatt (dBm) in time instance i and on a serving cell c is determined as:
P SRS,c (i)=min{P CMAX,c (i), 10 log 10 (M SRS,c )+P O_SRS,c ·α SRS,c ·PL c +f c (i)} dBm,
where:
min{x, y} is a minimum function resulting in a smaller of numbers x, y,
log 10 (x) is a logarithm function with base 10 resulting a logarithm with base 10 for number x,
P CMAX,c (i) is the maximum transmission power in time instance i configured by higher layers for the serving cell c,
M SRS,c is the bandwidth for the transmission of the SRS in time instance i and on the serving cell c,
P O_SRS,c is configured by higher layers for the serving cell c, m=0 when the transmission of the SRS is configured by higher layers, and m=1 when the SRS transmission is configured by the DCI format,
α SRS,c is configured by higher layers for the SRS on the serving cell c,
PL c is a path loss value measured on the serving cell c, and
f c (i) is a transmission power control adjustment state, determined from the TPC command in the DCI format, for SRS transmission in time instance i and on the serving cell c.
17. The method of claim 16 , wherein a power headroom (PH) for the transmission of the SRS in time instance i and on the serving cell c is determined based on:
PH c (i)=P CMAX,c (i)−{10 log 10 (M SRS,c (i))+P O SRS,c (m)+α SRS,c ·PL c +f c (i)}.
18. The method of claim 16 , wherein:
f c (0)=ΔP rampup,c ,
ΔP rampup,c =min[{max (0, P CMAX,c −(10 log 10 (M SRS,c )+P O_SRS,c (m)+α SRS,c ·PL c ))}, ΔP rampuprequested,c ],
where:
max{x, y} is a maximum function resulting the larger of numbers x, y,
M SRS,c is the bandwidth for the transmission of the SRS at a time instance of a first SRS transmission on the serving cell c, and
ΔP rampuprequested,c is a total power ramp-up power from a first to a last random access preamble transmission on the serving cell c and is configured by higher layers.
19. A base station (BS), comprising:
a transceiver configured to transmit a configuration for a location of first bits in a downlink control information (DCI) format, the DCI format comprising one or more blocks of bits including the first bits, wherein each of the one or more blocks of bits comprises
one or more bits for a transmit power control (TPC) command, and
zero or more bits for a request for transmission of a sounding reference signal (SRS); and
a processor operably coupled to the transceiver and configured to control reception of an SRS that was transmitted with an SRS transmission power based on a value of the one or more bits for the TPC command from the first bits and, when the first bits include one or more bits for the SRS request, a value of the one or more bits for the SRS request,
wherein the TPC command is used to control only the transmission power of the SRS,
wherein the transceiver is further configured to receive the SRS, and
wherein:
a power of the SRS transmission on a serving cell is determined to be a smaller value among a first value and a second value,
the first value is a maximum transmission power, and
the second value is determined based on power control parameters comprising a bandwidth for the SRS transmission on the serving cell, a path loss value measured on the serving cell, a transmission power control adjustment state on the serving cell determined from the TPC command, and higher layer parameters for the serving cell.
20. The BS of claim 19 , wherein:
a number of the one or more blocks of bits is more than one,
each of the more than one blocks of bits corresponds to a serving cell, and
each of the more than one blocks of bits comprises either TPC command bits or both TPC command bits and SRS request bits for the serving cell.
21. The BS of claim 20 , wherein the UE is not configured for a physical uplink shared channel (PUSCH) transmission and physical uplink control channel (PUCCH) transmission on a serving cell.
22. The BS of claim 19 , wherein:
the transceiver is configured to transmit a TPC-SRS-radio network temporary identifier (TPC-SRS-RNTI), and
a cyclic redundancy check (CRC) of the DCI format is scrambled by the TPC-SRS-RNTI.
23. The BS of claim 19 , wherein the zero or more bits for the SRS request are consecutive to the one or more bits for the TPC command in the DCI format.
24. The BS of claim 19 , wherein the SRS transmission power on w a cell is controlled based on:
a reference reception power for a physical uplink shared channel (PUSCH) transmission on the cell, when provided, and
a reference reception power for the SRS transmission on the cell, when a reference reception power for a PUSCH transmission on the cell is not provided.
25. The BS of claim 19 , wherein the transmission power P SRS,c (i) of the SRS in decibels per milliwatt (dBm) in time instance i and on a serving cell c is determined as:
P SRS,c (i)=min{P CMAX,c (i), 10 log 10 (M SRS,c )+P O_SRS,c +α SRS,c ·PL c +f c (i)} dBm,
where:
min{x, y} is a minimum function resulting in a smaller of numbers x, y,
log 10 (x) is a logarithm function with base 10 resulting a logarithm with base 10 for number x,
P CMAX,c (i) is the maximum transmission power in time instance i configured by higher layers for the serving cell c,
M SRS,c is the bandwidth for the transmission of the SRS in time instance i and on the serving cell c,
P O_SRS,c is configured by higher layers for the serving cell c, m=0 when the transmission of the SRS is configured by higher layers, and m=1 when the SRS transmission is configured by the DCI format,
α SRS,c is configured by higher layers for the SRS on the serving cell c,
PL c is a path loss value measured on the serving cell c, and
f c (i) is a transmission power control adjustment state, determined from the TPC command in the DCI format, for SRS transmission in time instance i and on the serving cell c.
26. The BS of claim 25 , wherein a power headroom (PH) for the transmission of the SRS in time instance i and on the serving cell c is determined based on:
PH c (i)=P CMAX,c (i)−{10 log 10 (M SRS,c (i))+P O_SRS,c (m)+α SRS,c ·PL c +f c (i)}.
27. The BS of claim 25 , wherein:
f c (0)=ΔP rampup,c ,
ΔP rampup,c =min[{max (0, P CMAX,c −(10 log 10 (M SRS,c )+P O_SRS,c (m)+α SRS,c ·PL c ))}, ΔP rampuprequested,c ],
max{x, y} is a maximum function resulting the larger of numbers x, y,
where:
M SRS,c is the bandwidth for the transmission of the SRS at a time instance of a first SRS transmission on the serving cell c, and
ΔP rampuprequested,c is a total power ramp-up power from a first to a last random access preamble transmission on the serving cell c and is configured by higher layers.
28. A method, comprising:
transmitting a configuration for a location of first bits in a downlink control information (DCI) format, the DCI format comprising one or more blocks of bits including the first bits, wherein each of the one or more blocks of bits comprises
one or more bits for a transmit power control (TPC) command, and
zero or more bits for a request for transmission of a sounding reference signal (SRS); and
receiving an SRS that was transmitted with an SRS transmission power based on a value of the bits for the TPC command from the first bits and, when the first bits include one or more bits for the SRS request, and a value of the one or more bits for the SRS request, wherein the TPC command is used to control only the transmission power of the SRS, wherein:
a power of the SRS transmission on a serving cell is determined to be a smaller value among a first value and a second value,
the first value is a maximum transmission power,
the second value is determined based on power control parameters comprising a bandwidth for the SRS transmission on the serving cell, a path loss value measured on the serving cell, a transmission power control adjustment state on the serving cell determined from the TPC command, and higher layer parameters for the serving cell.
29. The method of claim 28 , wherein:
a number of the one or more blocks of bits is more than one,
each of the more than one blocks of bits corresponds to a serving cell, and
each of the more than one blocks of bits comprises either TPC command bits or both TPC command bits and SRS request bits for the serving cell.
30. The method of claim 29 , wherein the UE is not configured for a physical uplink shared channel (PUSCH) transmission and physical uplink control channel (PUCCH) transmission on a serving cell.
31. The method of claim 28 , further comprising:
transmitting a TPC-SRS-radio network temporary identifier (TPC-SRS-RNTI),
wherein a cyclic redundancy check (CRC) of the DCI formation is scrambled by the TPC-SRS-RNTI.
32. The method of claim 28 , wherein the zero or more bits for the SRS request are consecutive to the one or more bits for the TPC command in the DCI format.
33. The method of claim 28 , wherein the SRS transmission power on a cell based on:
a reference reception power for a physical uplink shared channel (PUSCH) on the cell, when provided, and
a reference reception power for the SRS transmission on the cell, when a reference reception power for a PUSCH transmission on the cell is not provided.
34. The method of claim 28 , wherein the transmission power P SRS,c (i) of the SRS in decibels per milliwatt (dBm) in time instance i and on a serving cell c is determined as:
P SRS,c (i)=min{P CMAX,c (i), 10 log 10 (M SRS,c )+P O_SRS,c +α SRS,c ·PL c +f c (i)} dBm,
where:
min{x, y} is a minimum function resulting in a smaller of numbers x, y,
log 10 (x) is a logarithm function with base 10 resulting a logarithm with base 10 for number x,
P CMAX,c (i) is the maximum transmission power in time instance i configured by higher layers for the serving cell c,
M SRS,c is the bandwidth for the transmission of the SRS in time instance i and on the serving cell c,
P O_SRS,c is configured by higher layers for the serving cell c, m=0 when the transmission of the SRS is configured by higher layers, and m=1 when the SRS transmission is configured by the DCI format,
α SRS,c is configured by higher layers for the SRS on the serving cell c,
PL c is a path loss value measured on the serving cell c, and
f c (i) is a transmission power control adjustment state, determined from the TPC command in the DCI format, for SRS transmission in time instance i and on the serving cell c.
35. The method of claim 34 , wherein a power headroom (PH) for the transmission of the SRS in time instance i and on the serving cell c is determined based on:
PH c (i)=P CMAX,c (i)−{10 log 10 (M SRS,c (i))+P O_SRS,c (m)+α SRS,c ·PL c +f c (i)}.
36. The method of claim 34 , wherein:
f c (0)=ΔP rampup,c ,
ΔP rampup,c =min[{max (0, P CMAX,c −(10 log 10 (M SRS,c )+P O_SRS,c (m)+α SRS,c ·PL c ))}, ΔP rampuprequested,c ],
max{x, y} is a maximum function resulting the larger of numbers x, y,
where:
M SRS,c is the bandwidth for the transmission of the SRS at a time instance of a first SRS transmission on the serving cell c, and
ΔP rampuprequested,c is a total power ramp-up power from a first to a last random access preamble transmission on the serving cell c and is configured by higher layers.