5.1.3 Sounding Reference Symbol (SRS)
36.2133GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Physical layer proceduresRelease 17TS
5.1.3.1 UE behaviour
The setting of the UE Transmit power 
for the SRS transmitted on subframe i for serving cell 
is defined by:
for SRS transmission given trigger type 2 or for serving cell 
with frame structure type 2, and not configured for PUSCH/PUCCH transmission
[dBm]
otherwise
[dBm]
where
– 
is the configured UE transmit power defined in [6] in subframe i for serving cell 
.
– 
is semi-statically configured by higher layers for m=0 and m=1 for serving cell 
. For SRS transmission given trigger type 0 then m=0 and for SRS transmission given trigger type 1 then m=1.
– 
is the bandwidth of the SRS transmission in subframe i for serving cell 
expressed in number of resource blocks.
– 
is the current PUSCH power control adjustment state for serving cell 
, see Clause 5.1.1.1.
– 
and 
are parameters as defined in Clause 5.1.1.1 for subframe 
, where 
.
– 
is the higher layer parameter alpha-SRS for SRS transmission given trigger type 0, 1, or is the higher layer parameter alphaSRS-Add for SRS transmission given trigger type 2, configured by higher layers for serving cell 
.
– 
is a parameter composed of the sum of a component 
which is p0-Nominal-PeriodicSRS, p0-Nominal-AperiodicSRS, or p0-NominalSRS-Add provided from higher layers for m=0, 1 or 2 respectively, and a component 
which is p0-UE-PeriodicSRS, p0-UE-AperiodicSRS, or p0-UE-SRS-Add provided by higher layers for m=0, 1 or 2 respectively, for serving cell 
. For SRS transmission given trigger type 0 then m=0 and for SRS transmission given trigger type 1 then m=1 and for SRS transmission given trigger type 2 then m=2.
– For SRS transmission given trigger type 2 or for serving cell 
with frame structure type 2, and not configured for PUSCH/PUCCH transmission, the current SRS power control adjustment state is given by
and is defined by:
– 
if accumulation is enabled, and
if accumulation is not enabled based on higher layer parameter accumulation-Enabled, for SRS transmission given trigger type 0 or 1, or for higher layer parameter accumulationEnabled-additionalSRS given trigger type 2, where
– 
is a correction value, also referred to as a SRS TPC command signalled on PDCCH with DCI format 3 or 3A for SRS transmission given trigger type 2, or DCI format 3B for SRS transmission for trigger type 0, 1, 2 SRS in the most recent subframe 
, where 
.
– The UE is not expected to receive different SRS TPC command values for serving cell 
in the same subframe for SRS transmission given trigger type 0, or 1.
– The UE is not expected to receive different SRS TPC command values for serving cell 
in the same subframe for SRS transmission given trigger type 2.
– The UE attempts to decode a PDCCH of DCI format 3B with CRC scrambled by higher layer parameter srs-TPC-RNTI-r14in every subframe except where serving cell 
is deactivated.
– The UE attempts to decode a PDCCH of DCI format 3 or 3A with CRC scrambled by higher layer parameter TPC-PUSCH-RNTI in every subframe except where service cell 
is deactivated.
– 
dB for a subframe where no TPC command in PDCCH with DCI format 3/3A/3B is decoded for serving cell 
or i is not an uplink/special subframe in TDD or FDD-TDD and serving cell c frame structure type 2.
– If higher layer parameter fieldTypeFormat3B or fieldTypeFormat3B-SRS-Add indicates 2-bit TPC command, the 
dB values signalled on PDCCH with DCI format 3B are given in Table 5.1.1.1-2 by replacing 
with 
, or if higher layer parameter fieldTypeFormat3B or fieldTypeFormat3B-SRS-Add indicates 1-bit TPC command, the 
dB values signalled on PDCCH with DCI format 3B are given in Table 5.1.1.1-3 by replacing 
with 
.
– The 
dB values signalled on PDCCH with DCI format 3 are given in Table 5.1.1.1-2 by replacing 
with 
, and the 
dB values signalled on PDCCH with DCI format 3A are given in Table 5.1.1.1-3 by replacing 
with 
.
– If accumulation is enabled, 
is the first value after reset of accumulation. The UE shall reset accumulation
– For serving cell 
, when 
value is changed by higher layers
– For serving cell 
, when the UE receives random access response message for serving cell 
.
– For both types of 
(accumulation or current absolute) the first value is set as follows:
– If 
value is received by higher layers
– 
– else
– if the UE receives the random access response message for a serving cell 
– 
, where
is the TPC command indicated in the random access response corresponding to the random access preamble transmitted in the serving cell 
, see Clause 6.2, and 
and 
is provided by higher layers and corresponds to the total power ramp-up requested by higher layers from the first to the last preamble in the serving cell 
, 
is the bandwidth of the SRS transmission expressed in number of resource blocks valid for the subframe of first SRS transmission in the serving cell 
.
If the UE is not configured with an SCG or a PUCCH-SCell, and if the total transmit power of the UE for the Sounding Reference Symbol in an SC-FDMA symbol would exceed 
, the UE scales 
for the serving cell 
and the SC-FDMA symbol in subframe i such that the condition
is satisfied where 
is the linear value of 
, 
is the linear value of 
defined in [6] in subframe i and
is a scaling factor of 
for serving cell 
where 
. Note that
values are the same across serving cells.
If the UE is not configured with an SCG or a PUCCH-SCell, and if the UE is configured with multiple TAGs and the SRS transmission of the UE in an SC-FDMA symbol for a serving cell in subframe 
in a TAG overlaps with the SRS transmission in another SC-FDMA symbol in subframe 
for a serving cell in another TAG, and if the total transmit power of the UE for the Sounding Reference Symbol in the overlapped portion would exceed 
, the UE scales 
for the serving cell 
and each of the overlapped SRS SC-FDMA symbols in subframe 
such that the condition
is satisfied for all the overlapped SRS SC-FDMA symbol(s) in subframe 
where 
is the linear value of 
, is the transmit power of SRS trigger type 2 or trigger type 0/1 in subframe 
for serving cell 
, 
is the linear value of 
defined in [6] in subframe i and
is a scaling factor of 
for serving cell 
where 
. Note that
values are the same across serving cells.
If the UE is configured with a LAA SCell for uplink transmissions, the UE may compute the scaling factor 
assuming that the UE performs a SRS transmission on the LAA SCell in subframe i irrespective of whether the UE can access the LAA SCell for the SRS transmission in subframe i according to the channel access procedures described in Clause 4.2.1 of [13].
If the UE is configured with higher layer parameter UplinkPowerControlDedicated-v12x0 for serving cell 
and if subframe 
belongs to uplink power control subframe set 2 as indicated by the higher layer parameter tpc-SubframeSet-r12, the UE shall use 
instead of 
to determine 
for subframe i and serving cell 
, where 
is defined in Clause 5.1.1.1.
5.1.3.2 Power headroom for Type3 report
The UE is not expected to compute a Type 3 report on a slot/subslot.
For SRS transmission given trigger type 2, or for serving cell 
with frame structure type 2 and not configured for PUSCH/PUCCH transmission,
– if the UE transmits SRS in subframe 
for serving cell 
, or if the UE does not transmit SRS in subframe due to a collision with a higher priority physical channel or signal (as defined in Clause 8.2) in subframe, and the UE would have transmitted the SRS in subframe had the higher priority physical channel or signal in subframe not occurred, power headroom for a Type 3 report is computed using
[dB]
where
is defined in Clause 5.1.1.1. 
, 
, 
,
, 
are defined in Clause 5.1.3.1.
– otherwise, power headroom for a Type 3 report is computed using
[dB]
where
is defined in Clause 5.1.1.1., 
,
, 
are defined in Clause 5.1.3.1. 
is computed based on the requirements in [6] assuming a SRS transmission in subframe 
, and assuming MPR=0dB, A-MPR=0dB, P-MPR=0dB and TC =0dB. MPR, A-MPR, P-MPR and TC are defined in [6]. For this case, the physical layer delivers 
instead of 
to higher layers.