8.4 Performance requirements for PRACH
36.1043GPPBase Station (BS) radio transmission and receptionEvolved Universal Terrestrial Radio Access (E-UTRA)Release 18TS
8.4.1 PRACH False alarm probability
The false alarm requirement is valid for any number of receive antennas, for all frame structures and for any channel bandwidth.
The false alarm probability is the conditional total probability of erroneous detection of the preamble (i.e. erroneous detection from any detector) when input is only noise.
8.4.1.1 Minimum requirement
The false alarm probability shall be less than or equal to 0.1%.
8.4.2 PRACH detection requirements
The probability of detection is the conditional probability of correct detection of the preamble when the signal is present. There are several error cases – detecting different preamble than the one that was sent, not detecting a preamble at all or correct preamble detection but with the wrong timing estimation. For AWGN, a timing estimation error occurs if the estimation error of the timing of the strongest path is larger than 1.04us. For ETU70 and EPA1, a timing estimation error occurs if the estimation error of the timing of the strongest path is larger than 2.08us. The strongest path for the timing estimation error refers to the strongest path (i.e. average of the delay of all paths having the same highest gain = 310ns for ETU) in the power delay profile.
The test preambles for normal mode are listed in table A.6-1 and the test preambles for high speed mode restriced set type A are listed in A.6-2. The test preambles for coverage enhancement are listed in table A.6-3. The test preambles for high speed mode restriced set type B are listed in A.6-4.
8.4.2.1 Minimum requirements
The probability of detection shall be equal to or exceed 99% for the SNR levels listed in Tables 8.4.2.1-1 to 8.4.2.1-5.
The requirements for Burst format 4 are optional and only valid for base stations supporting TDD. The requirements for high speed mode restricted set type A (table 8.4.2.1-2) and high speed mode restricted set type B (table 8.4.2.1-5) are only valid for the base stations supporting high speed mode restricted set A and restricted set type B respectively.
The requirements for coverage enhancement (Tables 8.4.2.1-3 and 8.4.2.1-4) are only valid for the base stations supporting coverage enhancement.
Table 8.4.2.1-1 PRACH missed detection requirements for Normal Mode
|
Number of TX antennas |
Number of RX antennas |
Propagation conditions and correlation matrix (Annex B) |
Frequency offset |
SNR [dB] |
||||
|
Burst format 0 |
Burst format 1 |
Burst format 2 |
Burst format 3 |
Burst format 4 |
||||
|
1 |
2 |
AWGN |
0 |
-14.2 |
-14.2 |
-16.4 |
-16.5 |
-7.2 |
|
ETU 70 Low* |
270 Hz |
-8.0 |
-7.8 |
-10.0 |
-10.1 |
-0.1 |
||
|
4 |
AWGN |
0 |
-16.9 |
-16.7 |
-19.0 |
-18.8 |
-9.8 |
|
|
ETU 70 Low* |
270 Hz |
-12.1 |
-11.7 |
-14.1 |
-13.9 |
-5.1 |
||
|
8 |
AWGN |
0 |
-19.8 |
-19.4 |
-21.5 |
-21.3 |
-11.8 |
|
|
ETU 70 Low* |
270 Hz |
-16.3 |
-15.9 |
-17.8 |
-17.5 |
-8.6 |
||
|
Note*: Not applicable for Local Area BS and Home BS. |
||||||||
The requirements in Table 8.4.2.1-2 shall not be applied to Local Area BS and Home BS.
Table 8.4.2.1-2 PRACH missed detection requirements for High speed Mode restricted set type A
|
Number of TX antennas |
Number of RX antennas |
Propagation conditions and correlation matrix (Annex B) |
Frequency offset |
SNR [dB] |
|||
|
Burst format 0 |
Burst format 1 |
Burst format 2 |
Burst format 3 |
||||
|
1 |
2 |
AWGN |
0 |
-14.1 |
-14.2 |
-16.3 |
-16.6 |
|
ETU 70 Low |
270 Hz |
-7.4 |
-7.3 |
-9.3 |
-9.5 |
||
|
AWGN |
625 Hz |
-12.4 |
-12.3 |
-14.4 |
-14.4 |
||
|
AWGN |
1340 Hz |
-13.4 |
-13.5 |
-15.5 |
-15.7 |
||
|
4 |
AWGN |
0 |
-16.9 |
-16.6 |
-18.9 |
-18.8 |
|
|
ETU 70 Low |
270 Hz |
-11.8 |
-11.4 |
-13.7 |
-13.7 |
||
|
AWGN |
625 Hz |
-14.9 |
-14.6 |
-16.8 |
-16.8 |
||
|
AWGN |
1340 Hz |
-15.9 |
-15.5 |
-17.8 |
-17.8 |
||
|
8 |
AWGN |
0 |
-19.3 |
-19.1 |
-20.9 |
-21.0 |
|
|
ETU 70 Low |
270 Hz |
-15.6 |
-15.1 |
-17.0 |
-17.0 |
||
|
AWGN |
625 Hz |
-17.7 |
-17.4 |
-19.3 |
-19.4 |
||
|
AWGN |
1340 Hz |
-18.7 |
-18.4 |
-20.5 |
-20.5 |
||
Table 8.4.2.1-3 PRACH missed detection requirements for coverage enhancement (PRACH frequency hopping OFF)
|
Number of TX antennas |
Number of RX antennas |
Propagation conditions and correlation matrix (Annex B) |
Frequency offset |
Number of Repetitions |
SNR [dB] |
|||
|
Burst format 0 |
Burst format 1 |
Burst format 2 |
Burst format 3 |
|||||
|
1 |
2 |
AWGN |
0 |
4 |
– |
– |
-21.3 |
-21.1 |
|
8 |
-21.7 |
-21.3 |
– |
– |
||||
|
16 |
– |
– |
-25.1 |
-25.0 |
||||
|
32 |
-25.6 |
-25.3 |
– |
– |
||||
|
EPA1 Low |
270 Hz |
4 |
– |
– |
-12.1 |
-11.7 |
||
|
8 |
-13.0 |
-12.3 |
– |
– |
||||
|
16 |
– |
– |
-17.2 |
-17.2 |
||||
|
32 |
-19.0 |
-18.6 |
– |
– |
||||
|
Note 1: Under fading channels, the PRACH detection performance may be significantly different with different PRACH Configuration Indexes. The requirements in this table are defined based on the simulation results with PRACH Configuration Indexes (3, 19, 35, 51) for Format 0, Format 1, Format 2, and Format 3 respectively. |
||||||||
Table 8.4.2.1-4 PRACH missed detection requirements for coverage enhancement (PRACH frequency hopping ON)
|
Number of TX antennas |
Number of RX antennas |
Propagation conditions and correlation matrix (Annex B) |
Frequency offset |
Number of Repetitions |
SNR [dB] |
|||
|
Burst format 0 |
Burst format 1 |
Burst format 2 |
Burst format 3 |
|||||
|
1 |
2 |
EPA1 Low |
270 Hz |
4 |
– |
– |
-15.5 |
-15.3 |
|
8 |
-16.2 |
-15.8 |
– |
– |
||||
|
16 |
– |
– |
-20.1 |
-20.2 |
||||
|
32 |
-21.3 |
-21.1 |
– |
– |
||||
|
Note 1: Under fading channels, the PRACH detection performance may be significantly different with different PRACH Configuration Indexes. The requirements in this table are defined based on the simulation results with PRACH Configuration Indexes (3, 19, 35, 51) for Format 0, Format 1, Format 2, and Format 3 respectively. Note 2: The requirements in this table are defined under the assumption that UE RF tuning during PRACH frequency hopping has no impact on the symbols in PRACH subframes and thus all symbols in PRACH subframes are available for the transmission of PRACH preambles. Note 3: The requirements in this table are defined under the assumption that the PRACH frequency offset (prach-FreqOffset-r13) is 0 and frequency hopping offset is Note 4: The requirements in this table apply for channel bandwidth of 5MHz, 10MHz, 15MHz or 20MHz. For channel bandwidth of 3MHz, the requirements in Table 8.4.2.1-3 apply. |
||||||||
-6, where 
is defined in TS36.211 [12].Table 8.4.2.1-5 PRACH missed detection requirements for High speed Mode restricted set type B
|
Number of TX antennas |
Number of RX antennas |
Propagation conditions and correlation matrix (Annex B) |
Frequency offset |
SNR [dB] |
|||
|
Burst format 0 |
Burst format 1 |
Burst format 2 |
Burst format 3 |
||||
|
1 |
2 |
AWGN |
0 |
-14.5 |
-14.1 |
-16.7 |
-16.8 |
|
AWGN |
625 |
-12.0 |
-11.7 |
-13.9 |
-13.9 |
||
|
ETU 70 Low |
270 Hz |
-7.3 |
-6.9 |
-9.1 |
-9.2 |
||
|
AWGN |
1875 Hz |
-11.8 |
-11.4 |
-13.8 |
-14.0 |
||
|
AWGN |
1944 Hz |
-11.7 |
-11.4 |
-13.8 |
-14.0 |
||
|
4 |
AWGN |
0 |
-17.1 |
-16.6 |
-19.1 |
-19.1 |
|
|
AWGN |
625 |
-14.4 |
-14.1 |
-16.1 |
-16.2 |
||
|
ETU 70 Low |
270 Hz |
-11.8 |
-11.3 |
-13.5 |
-13.4 |
||
|
AWGN |
1875 Hz |
-14.2 |
-13.8 |
-15.9 |
-16.3 |
||
|
AWGN |
1944 Hz |
-14.2 |
-13.8 |
-15.9 |
-16.3 |
||
|
8 |
AWGN |
0 |
-19.6 |
-19.1 |
-21.2 |
-21.2 |
|
|
AWGN |
625 |
-16.4 |
-16.3 |
-18.1 |
-18.2 |
||
|
ETU 70 Low |
270 Hz |
-15.3 |
-15.1 |
-17.1 |
-17.5 |
||
|
AWGN |
1875 Hz |
-16.3 |
-16.0 |
-18.0 |
-18.4 |
||
|
AWGN |
1944 Hz |
-16.3 |
-16.0 |
-18.0 |
-18.4 |
||