5.2 Downlink power allocation
36.2133GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Physical layer proceduresRelease 17TS
The eNodeB determines the downlink transmit energy per resource element.
For the purpose of RSRP and RSRQ measurements, the UE may assume downlink cell-specific RS EPRE is constant across the downlink system bandwidth and constant across all subframes with discovery signal transmissions until different cell-specific RS power information is received.
For a cell that is not a LAA SCell, the UE may assume downlink cell-specific RS EPRE is constant across the downlink system bandwidth and constant across all subframes until different cell-specific RS power information is received.
The downlink cell-specific reference-signal EPRE can be derived from the downlink reference-signal transmit power given by the parameter referenceSignalPower provided by higher layers. The downlink reference-signal transmit power is defined as the linear average over the power contributions (in [W]) of all resource elements that carry cell-specific reference signals within the operating system bandwidth.
For a LAA SCell, the UE may assume that the EPRE of downlink cell-specific RS in subframe n is same as the EPRE of downlink cell-specific RS in subframe n-1, if all OFDM symbols of at least the second slot of subframe n-1, are occupied.
For a BL/CE UE, if the UE is configured with higher layer parameter RSS-Config, the ratio of resynchronization signal EPRE to cell-specific RS EPRE is given by higher layer parameter powerBoost in RSS-Config , where and are the default values for and in Table 5.2-1a assuming the same transmitted power for symbols with or without CRS, and is the number of CRS ports.
For a BL/CE UE, if the UE is configured with higher layer parameter WUS-Config, the ratio of MWUS EPRE to cell-specific RS EPRE is given by higher layer parameter powerBoost in WUS-Config, where and are the default values for and in Table 5.2-1a assuming the same transmitted power for symbols with or without CRS, and is the number of CRS ports.
For a BL/CE UE, if the UE is configured with higher layer parameter crs-ChEstMPDCCH-ConfigCommon or crs-ChEstMPDCCH-ConfigDedicated, the ratio of Demodulation RS EPRE to cell-specific RS EPRE is given by higher layer parameter powerRatio in crs-ChEstMPDCCH-ConfigCommon or crs-ChEstMPDCCH-ConfigDedicated.
The ratio of PDSCH EPRE to cell-specific RS EPRE among PDSCH REs (not applicable to PDSCH REs with zero EPRE) for each OFDM symbol is denoted by either 
or 
according to the OFDM symbol index as given by Table 5.2-2 and Table 5.2-3. In addition,
and 
are UE-specific.
For a UE in transmission mode 8 – 10 when UE-specific RSs are not present in the PRBs upon which the corresponding PDSCH is mapped or in transmission modes 1 – 7, the UE may assume that for 16 QAM, 64 QAM, 256QAM, or 1024QAM spatial multiplexing with more than one layer or for PDSCH transmissions associated with the multi-user MIMO transmission scheme, or for a UE in transmission modes 2-4 and configured with higher layer parameter must-Config-r14 the UE may assume that for QPSK,
– 
is equal to
[dB] when the UE receives a PDSCH data transmission using precoding for transmit diversity with 4 cell-specific antenna ports according to Clause 6.3.4.3 of [3];
– 
is equal to
[dB] otherwise
where
is 0 dB for all PDSCH transmission schemes except multi-user MIMO as described in Clause 7.1.5 and where
is a UE specific parameter provided by higher layers. If the UE is configured with higher layer parameter must-Config-r14, and if the UE is configured with higher layer parameter p-a-must-r14, and if the PDCCH/EPDCCH DCI of the corresponding PDSCH transmission indicates MUST interference is present [4], the UE shall use the higher layer parameter p-a-must-r14 for determining.
For a UE configured with higher layers parameter servCellp-a-r12, and the UE in transmission modes 8-10 when UE-specific RSs are not present in the PRBs upon which the corresponding PDSCH is mapped or in transmission modes 1-7, the UE may assume that for QPSK and transmission with single-antenna port or transmit diversity transmission schemes or spatial multiplexing using a single transmission layer, and the PDSCH transmission is not associated with the multi-user MIMO transmission scheme, and the PDSCH is scheduled by a PDCCH/EPDCCH with CRC scrambled by C-RNTI,
– 
is equal to 
[dB] when the UE receives a PDSCH data transmission using precoding for transmit diversity with 4 cell-specific antenna ports according to Clause 6.3.4.3 of [3];
– 
is equal to
[dB] otherwise
and where is given by the parameter servCellp-a-r12. If the UE is also configured with higher layer parameter must-Config-r14, and if the UE is configured with higher layer parameter p-a-must-r14, and if the PDCCH/EPDCCH DCI of the corresponding PDSCH transmission indicates MUST interference is present [4], the UE shall use the higher layer parameter p-a-must-r14 for determining 
.
For a cell supporting SC-PTM, the UE may assume that for the PDSCH scrambled by G-RNTI,
– 
is equal to 
[dB] when the UE receives a PDSCH data transmission using precoding for transmit diversity with 4 cell-specific antenna ports according to Clause 6.3.4.3 of [3];
– 
is equal to 
[dB] otherwise
where 
is configured per SC-MTCH and is given by higher layer parameter p-a-r13. If 
is not configured, the UE may assume that 
[dB].
For transmission mode 7, if UE-specific RSs are present in the PRBs upon which the corresponding PDSCH is mapped, the ratio of PDSCH EPRE to UE-specific RS EPRE within each OFDM symbol containing UE-specific RSs shall be a constant, and that constant shall be maintained over all the OFDM symbols containing the UE-specific RSs in the corresponding PRBs. In addition, the UE may assume that for 16QAM, 64QAM, 256QAM, or 1024QAM this ratio is 0 dB.
For transmission mode 8, if UE-specific RSs are present in the PRBs upon which the corresponding PDSCH is mapped, the UE may assume the ratio of PDSCH EPRE to UE-specific RS EPRE within each OFDM symbol containing UE-specific RSs is 0 dB.
For transmission mode 9 or 10, if UE-specific RSs are present in the PRBs upon which the corresponding PDSCH is mapped, the UE may assume the ratio of PDSCH EPRE to UE-specific RS EPRE within each OFDM symbol containing UE-specific RS is 0 dB for number of transmission layers less than or equal to two and -3 dB otherwise.
A UE may assume that downlink positioning reference signal EPRE is constant across the positioning reference signal bandwidth and across all OFDM symbols that contain positioning reference signals in a given positioning reference signal occasion [10].
For the purpose of RSRP and RSRQ measurements on CSI-RS of a discovery signal the UE may assume that the EPRE of CSI-RS is constant across the downlink system bandwidth and constant across all subframes with discovery signal transmissions for each CSI-RS resource.
If a serving cell is not configured for a UE as a LAA SCell, and if CSI-RS is configured in the serving cell then the UE shall assume downlink CSI-RS EPRE is constant across the downlink system bandwidth and constant across all subframes for each CSI-RS resource.
If a serving cell is configured for a UE as a LAA SCell, the UE may assume that EPRE of CSI-RS in subframe n2 is same as EPRE of CSI-RS in earlier subframe n1, if all OFDM symbols of subframe n1 and all subframes between subframe n1 and subframe n2, are occupied.
The cell-specific ratio 
is given by Table 5.2-1 according to cell-specific parameter 
signalled by higher layers and the number of configured eNodeB cell specific antenna ports. 
is given by higher layer parameter p-b-r13 for PDSCH scrambled by G-RNTI and by higher layer parameter p-b otherwise. In case PDSCH is scrambled by G-RNTI, if 
is not configured, the UE may assume that 
.
Table 5.2-1: The cell-specific ratio 
for 1, 2, or 4 cell specific antenna ports
|
|
|
|
|
One Antenna Port |
Two and Four Antenna Ports |
|
|
0 |
1 |
5/4 |
|
1 |
4/5 |
1 |
|
2 |
3/5 |
3/4 |
|
3 |
2/5 |
1/2 |
Table 5.2-1a: and for 1, 2, or 4 cell specific antenna ports
assuming the same transmitted power for symbols with or without CRS
|
One Antenna Port |
Two and Four Antenna Ports |
|||
|
0 |
1 |
1 |
1 |
5/4 |
|
1 |
1/2 |
2/5 |
1/2 |
1/2 |
|
2 |
1/3 |
1/5 |
1/3 |
1/4 |
|
3 |
1/4 |
1/10 |
1/4 |
1/8 |
For PMCH with 16QAM, 64QAM, or 256QAM, the UE may assume that the ratio of PMCH EPRE to MBSFN RS EPRE is equal to 0 dB.
Table 5.2-2: OFDM symbol indices within a slot of a non-MBSFN subframe where the ratio of the corresponding PDSCH EPRE to the cell-specific RS EPRE is denoted by 
or 
|
Number of antenna ports |
OFDM symbol indices within a slot where the ratio of the corresponding PDSCH EPRE to the cell-specific RS EPRE is denoted by |
OFDM symbol indices within a slot where the ratio of the corresponding PDSCH EPRE to the cell-specific RS EPRE is denoted by |
||
|
Normal cyclic prefix |
Extended cyclic prefix |
Normal cyclic prefix |
Extended cyclic prefix |
|
|
One or two |
1, 2, 3, 5, 6 |
1, 2, 4, 5 |
0, 4 |
0, 3 |
|
Four |
2, 3, 5, 6 |
2, 4, 5 |
0, 1, 4 |
0, 1, 3 |
Table 5.2-3: OFDM symbol indices within a slot of an MBSFN subframe where the ratio of the corresponding PDSCH EPRE to the cell-specific RS EPRE is denoted by 
or 
|
Number of antenna ports |
OFDM symbol indices within a slot where the ratio of the corresponding PDSCH EPRE to the cell-specific RS EPRE is denoted by |
OFDM symbol indices within a slot where the ratio of the corresponding PDSCH EPRE to the cell-specific RS EPRE is denoted by |
||||||
|
Normal cyclic prefix |
Extended cyclic prefix |
Normal cyclic prefix |
Extended cyclic prefix |
|||||
|
|
|
|
|
|
|
|
|
|
|
One or two |
1, 2, 3, 4, 5, 6 |
0, 1, 2, 3, 4, 5, 6 |
1, 2, 3, 4, 5 |
0, 1, 2, 3, 4, 5 |
0 |
– |
0 |
– |
|
Four |
2, 3, 4, 5, 6 |
0, 1, 2, 3, 4, 5, 6 |
2, 4, 3, 5 |
0, 1, 2, 3, 4, 5 |
0, 1 |
– |
0, 1 |
– |
mod 2 = 0
mod 2 = 1
mod 2 = 0
mod 2 = 1
mod 2 = 1
mod 2 = 0
mod 2 = 15.2.1 eNodeB Relative Narrowband TX Power (RNTP) restrictions
The determination of reported Relative Narrowband TX Power indication 
is defined as follows:
where 
is the maximum intended EPRE of UE-specific PDSCH REs in OFDM symbols not containing RS in this physical resource block on antenna port p in the considered future time interval;
is the physical resource block number 
; 
takes on one of the following values
[dB] and
where 
is the base station maximum output power described in [7], and 
, 
and
are defined in [3].