5G NR
The Physical Random Access Channel (PRACH) is used to carry random access preamble for the UE towards the gNB (for example, a 5G NR base station. It assists gNB to adjust uplink timings of the UE in addition to other parameters.
5G NR random access preamble supports two different sequence lengths with various format configurations. These different formats help in wide deployment situations.
This topic describes the following PRACH properties:
Number of PRACH slots within a subframe
Number of time-domain PRACH occasions within a PRACH slot
Msg1 Frequency Start (n_RA_start)
Sets the spectrum type for the selected PRACH. Choices available are based on the frequency (FR1 or FR2) set in Carrier > Cell-Specific > Numerology.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Configuration Table |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:CTABle FR1Paired|FR1Unpaired|FR2Unpaired [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:CTABle? |
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SCPI Example |
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Preset |
FR1 Paired Spectrum/Supplementary ulink |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
The random access configuration parameters for PRACH are set based on the Configuration Index setting in accordance with either Table 6.3.3.2-2 (FR1 Bandwidth and Paired or Supplementary Spectrum Type), Table 6.3.3.2-3 (FR1 Bandwidth and Unpaired Spectrum Type), or Table 6.3.3.2-4 (FR2 Bandwidth and Unpaired Spectrum Type) of the 3GPP TS 38.211 V15.3.0 (2018-10) standard
Entering -1 means user-defined PRACH, not restricted to the configuration table. User defined, however, does not work well with Export 89600 VSA Setup.
When recalling a settings file (*.scp) with N7631C v2.0, the configuration index is automatically set to -1 for backwards compatibility.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Configuration Index |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:CINDex <integer> [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:CINDex? |
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SCPI Example |
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Preset |
16 |
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State Saved |
Yes |
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Min |
-1 |
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Max |
262 |
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Resolution |
1 |
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Initial S/W Revision |
A.09.00 |
Displays the PRACH preamble format. The preamble format is determined by the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired or Unpaired).
The format A0 is removed in the latest standard. It is kept in our Signal Studio following the old version (38.211 v1.2).
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource >PRACH Format |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:FORMat F0|F1|F2|F3|FA0|FA1|FA2|FA3|FB1|FB2|FB3|FB4|FC0|FC2|FA1B1|FA2B2|FA3B3 [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:FORMat? |
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SCPI Example |
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Preset |
FR1 Paired Spectrum/Supplementary ulink |
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State Saved |
Yes |
| Choices | 0 |1 | 2 | 3 | A0 | A1 | A2 | A3 | B1 | B2 | B3 | B4 | C0 | C2 |
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Initial S/W Revision |
A.09.00 |
Display the Frame Period determined by the configuration table and configuration index, corresponding to the 'x' in the associated 3GPP TS 38.211 V15.3.0 (2018-10) standard..
Table 6.3.3.2-2 (FR1 Bandwidth and Paired or Supplementary Spectrum Type)
Table 6.3.3.2-3 (FR1 Bandwidth and Unpaired Spectrum Type)
Table 6.3.3.2-4 (FR2 Bandwidth and Unpaired Spectrum Type)
Not available if the Configuration Index is set to -1.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Frame Period |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:FRAMe:PERiod? |
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SCPI Example |
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Preset |
8 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Display the Frame Period determined by the configuration table and configuration index, corresponding to the 'y' in the associated 3GPP TS 38.211 V15.3.0 (2018-10) standard..
Table 6.3.3.2-2 (FR1 Bandwidth and Paired or Supplementary Spectrum Type)
Table 6.3.3.2-3 (FR1 Bandwidth and Unpaired Spectrum Type)
Table 6.3.3.2-4 (FR2 Bandwidth and Unpaired Spectrum Type)
Not available if the Configuration Index is set to -1.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Frame Offset |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:FRAMe:OFFSet? |
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SCPI Example |
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Preset |
1 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Displays the Slot Index determined by the configuration table and configuration index. The range: depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired or Unpaired).
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Slot Index |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:SLOT:INDex? |
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SCPI Example |
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Preset |
1 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Sets the symbol start of PRACH when PRACH format is not 0,1, 2, 3. The range: depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired or Unpaired).
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Symbol Start |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:SYMBol:STARt <integer> |
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SCPI Example |
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Preset |
0 |
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State Saved |
Yes |
| Min | 0 |
| Max | 13 |
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Initial S/W Revision |
A.09.00 |
Displays the Number of PRACH slots within a subframe (60 kHz slot). The range: depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired or Unpaired).
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Number of PRACH slots within a subframe |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:SLOT:NUMBer? |
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SCPI Example |
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Preset |
-1 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Displays the Number of time-domain PRACH occasions with in a PRACH slot. The range: depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired or Unpaired).
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Number of time-domain PRACH occasions within a PRACH slot |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:OCCasions? |
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SCPI Example |
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Preset |
-1 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Display the PRACH duration determined by the configuration table and configuration index.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > PRACH duration |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:DURation? |
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SCPI Example |
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Preset |
0 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Selects the subcarrier spacing of the PRACH.
The valid choices are based on the PRACH format, see more information in Table 6.3.3.1-1 and 6.3.3.1-2 of 38.211.
When PRACH format is 0, 1, 2 (only when Cell-Specific > Bandwidth is FR1), the Subcarrier Spacing for PRACH can only be 1.25 kHz
When PRACH format is 3 (only when Cell-Specific > Bandwidth is FR1), the Subcarrier Spacing for PRACH can only be 5 kHz
When PRACH format is A0…C2, the Subcarrier Spacing for PRACH can be 15 kHz or 30 kHz when Cell-Specific > Bandwidth is FR1 or 60 kHz or 120 kHz when Cell-Specific > Bandwidth is FR2
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Subcarrier Spacing for PRACH |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:SCSPacing SCS15K|SCS30K|SCS60K|SCS120K|SCS1K25|SCS5K [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:SCSPacing? |
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SCPI Example |
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Preset |
SCS1K25 (1.25 kHz) |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Sets the RRC msg1-FrequencyStart parameter of the PRACH preamble. This parameter, along with FDM, determines the frequency domain location for the PRACH preamble.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Msg1 Frequency Start (n_RA_start) |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:M1FStart <integer> [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:M1FStart? |
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SCPI Example |
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Preset |
0 |
| Choices | FDM 1, FDM 2, FDM 4, FDM 8 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Sets the RRC msg1-FDM parameter of the PRACH preamble. This parameter, along with Frequency Start, determines the frequency domain location for the PRACH preamble.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Time-domain Resource > Msg1 FDM |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:M1FStart <integer> [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:M1FStart? |
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SCPI Example |
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Preset |
1 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Sets the root sequence index for the selected PRACH. The root sequence index is consecutive to 837 when LRA = 839 (when Carrier > Cell-Specific > Numerology is set to FR2) and to 137 when LRA = 139 (when Carrier > Cell-Specific > Numerology is set to FR1).
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Sequence Generation > PRACH Root Sequence Index |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:RSINdex <integer> [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:RSIndex? |
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SCPI Example |
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Preset |
0 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Sets the type of restricted set for the selected PRACH, per Tables 6.3.3.1-1 and 6.3.3.1-2 of the standard.
Choices are: Unrestricted Set, Restricted set type A, and Restricted set type B.
It is only available when the Configuration Index is set to -1 (User Defined) and PRACH format is 0,1, 2, or 3.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Sequence Generation > Restricted Set Config |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:RSET:CONFig NONE|TYPEA|TYPEB [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:RSET:CONFig? |
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SCPI Example |
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Preset |
Unrestricted Set |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Sets the number of Root Sequences required per cell for the selected PRACH.
The range is based on the subcarrier spacing of PRACH and restricted set config.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Sequence Generation > Zero Correlation Zone Config |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:ZCZConfig <integer> [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:ZCZConfig? |
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SCPI Example |
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Preset |
0 |
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State Saved |
Yes |
| Min | 0 |
| Max | 15 |
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Initial S/W Revision |
A.09.00 |
Displays the LRA, which is determined by the preamble Format in accordance with Table 6.3.3.1-1 and Table 6.3.3.1-2 of the 3GPP TS 38.211 standard.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Sequence Generation > L_RA |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:LRA <integer> [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:LRA? |
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SCPI Example |
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Preset |
839 |
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State Saved |
Yes |
| Min | 139 |
| Max | 1151 |
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Initial S/W Revision |
A.09.00 |
Displays the NCS, which is determined by the PRACH Subcarrier Spacing in accordance with Table 6.3.3.1-1 and Table 6.3.3.1-2 of the 3GPP TS 38.211 standard.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Sequence Generation > N_CS |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:NCS? |
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SCPI Example |
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Preset |
0 |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Sets the Active Uplink BWP parameters used for PRACH transmission.
Displays the cell-specific numerology for the current BWP.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Active Uplink BWP > Numerology |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:UBWP:NUMerology? |
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SCPI Example |
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Preset |
30 kHz (MU1) |
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State Saved |
Yes |
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Initial S/W Revision |
A.09.00 |
Sets the RB offset of the BWP relative to CRB0.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Active Uplink BWP > RB Offset (N_BWP_start) |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:UBWP:RB:OFFSet <integer> [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:UBWP:RB:OFFSet? |
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SCPI Example |
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Preset |
0 |
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State Saved |
Yes |
| Min | 0 |
| Max | 272 |
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Initial S/W Revision |
A.09.00 |
Sets the RB number of the BWP.
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GUI Location |
Apps > 5G NR > Carrier PRACH > PRACH > Active Uplink BWP > RB Offset (N_BWP_start) |
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SCPI Command |
[:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:UBWP:RB:NUMBer <integer> [:SOURce]:RADio:NR5G:WAVeform[:ARB]:CCARrier<carrier>:PRACh:UBWP:RB:NUMBer? |
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SCPI Example |
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Preset |
273 |
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State Saved |
Yes |
| Min | 1 |
| Max | 273 |
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Initial S/W Revision |
A.09.00 |