HE-SIG-A1

The first HE-SIG-A symbol — mostly PHY parameters.

Subfields

• Format — Distinguishes an HE SU PPDU from an HE trigger-based one.
• Beam Change — Whether the spatial mapping changes between the legacy and HE portions.
• UL/DL — Direction of the transmission.
• MCS — Modulation and coding scheme for the data field.
• DCM — Dual carrier modulation, trading throughput for robustness.
• BSS Color — A short identifier for the transmitting BSS.
• Spatial Reuse — Whether and how neighbouring stations may transmit concurrently.
• Bandwidth — Channel width used for this transmission.
• GI+LTF Size — Guard interval and HE-LTF symbol duration.
• NSTS and Midamble Periodicity — Number of space-time streams, and midamble spacing where used.

Where it sits

HE SU PPDU > HE-SIG-A > HE-SIG-A1

• Open in the explorer — Ack
• Open in the explorer — TCP over IPv4, in a protected QoS Data frame, aggregated
• Open in the explorer — Association Request
• Open in the explorer — Association Response
• Open in the explorer — Beacon
• Open in the explorer — Compressed Block Ack
• Open in the explorer — CTS
• Open in the explorer — Four-way handshake message 1
• Open in the explorer — Four-way handshake message 2
• Open in the explorer — Four-way handshake message 3
• Open in the explorer — Four-way handshake message 4
• Open in the explorer — Probe Request
• Open in the explorer — Probe Response
• Open in the explorer — ARP request in a QoS Data frame
• Open in the explorer — ICMP echo over IPv4, in a QoS Data frame
• Open in the explorer — UDP over IPv6, in a QoS Data frame
• Open in the explorer — TCP over IPv4, in a protected QoS Data frame
• Open in the explorer — TCP over IPv4, in an open QoS Data frame
• Open in the explorer — UDP over IPv4, in a QoS Data frame
• Open in the explorer — RTS
• Open in the explorer — Trigger frame

Accuracy

Clause

802.11-2024 §27.3.11.6

Verified

Not verified against the standard. Treat this as a claim, not a fact.