PRACH (5G NR/5G-Advanced)
The panel contains the available parameters for one or more physical random access channel.
Demodulating multiple occasions within a single PRACH Physical Random Access Channel is supported. However, demodulating multiple PRACHs simultaneously is not supported. You can configure the VSA for multiple PRACHs; however, enable one PRACH at time during analysis.
Add PRACH - Adds a PRACH to the transmission. When a PRACH is added, a representative button is added at the top of the PRACH parameter group.
Remove PRACH - Removes the selected PRACH.
Clear All - Removes all but the original PRACH.
Enable Channels... - Quickly enables and disables the configured PRACHs in a single dialog. You can also enable channels individually using the Enabled checkbox at the top of each PRACH.
Enabled - Enables or disables the selected PRACH. You can also control all configured PRACHs using the Enabled Channels dialog.
BWP ID - Assigns the selected PRACH to one of the five available bandwidth parts.
Default: BWP0
Choices: BWP0, BWP1, BWP2, BWP3, BWP4
Spectrum Type - Sets the spectrum type for the selected PRACH. The spectrum type and FR1/FR2 (Bandwidth) selection determine the standard-based configuration table used when Use Configuration Index is enabled.
Default: Paired
Choices: Paired, Unpaired, Supplementary
General/Sequence
Subcarrier Spacing - Sets the subcarrier spacing for the selected PRACH. The available Subcarrier Spacing choices depend on the FR1/FR2/FR2-2 (Bandwidth) selection and the preamble Format in accordance with the 3GPP TS Technical Specification 38.211 standard.
Default: 15 kHz kiloHertz: A radio frequency measurement (one kilohertz = one thousand cycles per second).
Choices: 1.5 kHz, 5 kHz, 15 kHz, 30 kHz, 60 kHz, 120 kHz, 480 kHz, 960 kHz
Restricted Set - 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, the Unrestricted type is available for preamble formats A1-A3, B1-B4, C0 and C2. Restricted Type A and Restricted Type B are available for preamble formats 0-3.
Default: Unrestricted
Range: Unrestricted, Restricted Type A, Restricted Type B
RootSequenceIndex-r16 Configured - When enabled (selected), this setting configures the PRACH root sequence index and related settings based on Rel. 16 and later of the 3GPP standard.
RootSequenceIndex-r16 - (when RootSequenceIndex-r16 Configured is enabled) Sets the PRACH root sequence index based on Rel. 16 of the 3GPP standard. The root sequence index is consecutive to the LRA value minus 2 (LRA-2).
Default: 0
Range: 0 to (LRA-2)
Root Sequence Index - (when RootSequenceIndex-r16 Configured is disabled) Sets the root sequence index for the selected PRACH. The root sequence index is consecutive to the LRA value minus 2 (LRA-2).
Default: 0
Range: 0 to (LRA-2)
Zero Correlation Zone Config - Sets the number of Root Sequences required per cell for the selected PRACH.
Default: 0
Range: 0 to 15
Ncs - 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.
Default: 0
LRA - Displays the LRA 1) Random Access, or 2) Receiver Address, 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.
In most cases, the LRA parameter is grayed out and not selectable because its value is determined by PRACH Numerology and whether RootSequenceIndex-Rel16 is enabled. LRA selection is only enabled and selectable when RootSequenceIndex-r16 is enabled and Numerology is 120 kHz because the standard allows a choice of either 571 or 1151 in that case.
When RootSequenceIndex-r16 is enabled, the third and fourth column of Table 6.3.3.1-2 is used to decide the LRA value(s). When RootSequenceIndex-Rel16 is disabled, the second column of Table 6.3.3.1-1 and Table 6.3.3.1-2 are used to decide LRA.
Default: 139
Choices: 139, 571, 839, 1151
Time/Frequency Allocation
Configuration Index - When Use Configuration Index is enabled, the random access configuration parameters for this 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.
Default: 87
Choices: 0 - 255 (FR1); 0 - 24 (FR2)
Msg1 FDM - 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.
Default: FDM 1
Choices: FDM 1, FDM 2, FDM 4, FDM 8
Msg1 Frequency Start - Sets the RRC msg1-FrequencyStart parameter of the PRACH preamble. This parameter, along with FDM, determines the frequency domain location for the PRACH preamble.
Default: 0
Choices: 0 to (max number of resource blocks - 1)
Resource Mapping
Format - Displays the PRACH preamble format. The preamble format is determined by the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired, Unpaired or Supplementary). See Configuration Index for more information.
Default: Format A1
Choices: Format A1, Format A2, Format A3, Format B1, Format B2, Format B3, Format B4, Format C0, Format C2, Format A1/B1, Format A2/B2, Format A3/B3, Format 0, Format 1, Format 2, Format 3
Time Occasions - Displays the number of time occasions per PRACH slot based on the selected Configuration Index. See Configuration Index for more information.
Default: 6
Range: Depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired, Unpaired or Supplementary). See Configuration Index for more information.
Frame Period - Displays the configured frame period.
Default: 16
Range: Depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired, Unpaired or Supplementary). See Configuration Index for more information.
Frame Offsets - Displays the frame offset for the configuration.
Default: 0
Range: Depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired, Unpaired or Supplementary). See Configuration Index for more information.
Subframes/Slots
Subframe/Slot Indexes - Displays the subframe (FR1) or slot (FR2) indexes for the configuration.
Default: 4,9
Range: Depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired, Unpaired or Supplementary). See Configuration Index for more information.
First Symbol in Subframe/Slot - Sets the first symbol in the subframe (FR1) or slot (FR2) for the configuration.
Default: 0
Range: Depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired, Unpaired or Supplementary). See Configuration Index for more information.
PRACH Slots Per Subframe/Slot - Sets the number of PRACH slots within a subframe (FR1) or slot (FR2).
Default: 1
Range: Depends on the Configuration Index, Bandwidth (FR1 or FR2) and Spectrum Type (Paired, Unpaired or Supplementary). See Configuration Index for more information.
Occasions
Add Occasion - Adds an Occasion to the PRACH. When an Occasion is added, a representative button is added at the top of the Occasions parameter group.
Remove Occasion - Removes the selected Occasion.
Use Occasion Index - Enables or disables the Occasion Index. When enabled, The Occasion Index parameter decides the time domain and frequency domain location of the occasion (Subframe/Slot Index, nRA_slot, nRA_t and nRA_f).
Default: Enabled (checked)
Choices: Enabled, Disabled
Enabled - Enables the selected Occasion.
Default: Enabled (checked)
Choices: Enabled, Disabled
Occasion Index - Sets the occasion index when Use Occasion Index is enabled.
Default: 0
Preamble Index - Sets the preamble index for the selected PRACH.
Default: 0
Range: depends on Zero Correlation Zone Config
Subframe/Slot Index - Selects the subframe (FR1) or slot (FR2) index. This parameter is grayed out and automatically determined by the Occasion Index when Use Occasion Index is enabled.
Default: 4
Choices: depends on the PRACH configuration.
nRA_slot - Sets the nRA slot. This parameter is grayed out and automatically determined by the Occasion Index when Use Occasion Index is enabled.
Default: 0
Choices: depends on the PRACH configuration.
nRA_t - Sets the nRA_t, which is the PRACH transmission occasion within the PRACH slot. This parameter is grayed out and automatically determined by the Occasion Index when Use Occasion Index is enabled.
Default: 0
Choices: numbered in increasing order from 0 to (Time Occasions Per PRACH Slot-1)
nRA_f - Sets the nRA_f (frequency domain allocation). This parameter is grayed out and automatically determined by the Occasion Index when Use Occasion Index is enabled.
Default: 0
Choices: depends on the PRACH configuration.
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Demodulation may fail in PRACH manual mode (PRACH auto detection disabled) when multiple occasions are configured with the same Preamble Index and frequency domain index (nRA_f) |
Power Boosting
Power Boosting - Sets the relative power boosting (in dB) of the PRACH physical channel. This is a power scaling based on the constellation defined in 5.1.3/4/5/6 of 38.211.
Default: 0 dB
See Also
5G NR/5G-Advanced Demod Properties Dialog Box
