OFDM Demod:Results:Header:Payload Length (bytes) Property
- Updated2023-02-21
- 2 minute(s) read
Short Name: Detected OFDM Payload Length (bytes)
Property of niWLANAnalysis
Returns the length of the physical-layer payload If you set the OFDM Header Detection Enabled property to True, the toolkit extracts the payload length from the demodulated SIGNAL field or HT SIGNAL field, VHT-SIG-B field or TVHT-SIG-B of the frame, if you set the Standard property to 80211A/G OFDM, 80211J OFDM, 80211P OFDM (section 17.3.4 of IEEE Standard 802.11a-1999) or 80211N MIMOOFDM (section 20.3.9.4.3 of IEEE Standard 802.11n-2009), 80211AC MIMOOFDM (section 22.3.8.3.6 of IEEE Standard 80211ac-2013) respectively, or 80211AF MIMOOFDM (section 23.3.8.3.6 of IEEE Standard 80211af-2013). This value is expressed in bytes.
If you set the Standard property to 80211AH MIMOOFDM and the OFDM Header Detection Enabled property to True, the toolkit derives the payload length from the S1G-SIG/SIG-A field of the frame.
If you set the Standard property to 80211AX MIMOOFDM and the OFDM Header Detection Enabled property to True, the toolkit derives the payload length from the decoded data bits.
If you set the OFDM Header Detection Enabled property to False, the value you specify in the OFDM Payload Length property specifies the payload length. The toolkit returns a value of -1 if it encounters various data lengths during the averaging process.
You must use the following active channel string formats to query this property.
| Standard Property Value | PPDU Type | Active Channel String Syntax |
|---|---|---|
| 80211N MIMOOFDM, 80211AH MIMOOFDM, 80211AF MIMOOFDM | "" (empty string) | |
| 80211AC MIMOOFDM | SU PPDU | "" (empty string) |
| MU PPDU | "userx" | |
| 80211AX MIMOOFDM | SU PPDU, Extended Range SU PPDU | "" (empty string) |
| MU PPDU, Trigger-Based PPDU | "userx" |
Remarks
The following table lists the characteristics of this property.
| Datatype |  |
| Permissions | Read Only |
| High-level VIs | N/A |
| Resettable | No |