PSDU Decoded Bits (802.11n/ac/ax/be)
The trace is controlled by the Decode PSDU and Verify CRCs checkbox. When it is not checked, this trace shows “NO DATA”. When it is checked, the bits for all of the MPDUs for a user that have valid CRCs are shown in the trace, even though other MPDUs for that user may fail CRC Cyclic Redundancy Check. There will be 10 bits of zero for MPDUs with failed CRCs in the trace. If all the MPDU medium access control (MAC) protocol data unit: The unit of data exchanged between two peer MAC entities using the services of the physical layer (PHY). CRCs fail, then "0000" is shown in the trace.
By default, the bits are displayed in 8-bit bytes in hexadecimal format. Like other bit displays in the VSA software, the Trace > Digital Demod dialog can be used to switch from hex to binary.
Each user in the signal is displayed with a different color, and the colors match the colors of the OFDM Multi-User Info table. When a marker is placed in the PSDU 1) PHY Service Data Unit, or 2) PLCP SDU Decoded Bits trace, the marker annotation shows the user name, which matches the name in the Multi-User Info table. For example, in the picture below, the marker is on byte number 320, which belongs to “RU1_User1”, and has a value of FF (hex) = 255 (decimal). To navigate the decoded bits in the trace, drag the marker to the desired location or use the arrow keys.
The above assumes that the CRC for each users passes. If the CRC fails, then the bits for that user are not displayed, and instead there are just 16 bits of zeros displayed for that user. The pass/fail status of the CRC is shown in the Multi-User Info table.
As an example, in the display below, there are a total of 12 users, but all except one have a failing CRC. The user which has a passing CRC is RU2_User0, shown in yellowish-brown. The marker is within that user’s bits. All the other users show only four zeros (which is 2 bytes, or 16 bits).
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