Wi-Fi 6 OFDMA Resource Scheduler

Schedule Wi-Fi 6 resource units and compare OFDMA turns with legacy full-channel Wi-Fi turns

Learner-ready Wi-Fi 6 OFDMA scheduler with a visual RU map, scenario presets, Play/Step/Reset controls, channel and traffic controls, diagnosis cards, formula trace, quick reference, guided practice, and source links.

Wi-Fi 6 802.11ax OFDMA Resource units

Schedule many small Wi-Fi packets in one coordinated channel turn.

Legacy Wi-Fi gives one station the full channel for each turn. Wi-Fi 6 OFDMA lets the access point divide a channel into resource units so several HE-capable stations can send or receive in the same coordinated transmission opportunity.

Scheduled now 0 clients

Channel plan 20 MHz

OFDMA wait 0 TXOPs

Risk to watch RU fit

Beginner ramp

Three ideas before the scheduler starts

OFDMA is easiest to understand if you separate channel access, resource units, and scheduling direction.

One channel can be sliced

A resource unit is a group of OFDM tones assigned to one station inside a Wi-Fi 6 PPDU. Small sensors can use small RUs while larger flows use larger RUs.

The AP coordinates the turn

The access point chooses which stations fit in the next scheduled turn. For uplink OFDMA, stations transmit after an AP trigger frame.

Legacy clients still matter

Older clients do not join OFDMA RU sharing. They can still contend for full-channel turns, so a mixed network can reduce the latency gain.

Scenario presets

Choose a traffic pattern

Each preset changes the channel width, traffic mix, legacy clients, and scheduling policy.

Scheduler controls

Transmission direction Downlink OFDMA Uplink trigger Legacy full channel Downlink groups AP-to-client data. Uplink groups client-to-AP data after a trigger frame.

Channel width 20 MHz 40 MHz 80 MHz Wider channels create a larger RU budget, but they are not always available or clean in real deployments.

Wi-Fi 6 clients

12

Only HE-capable clients can be placed in OFDMA RUs in this teaching model.

Legacy clients

2

Legacy stations consume separate full-channel turns in the comparison.

Traffic mix Mostly tiny sensors Balanced IoT mix Alarm bursts Cameras and dashboards Bulk sync heavy The mix decides whether stations ask for small 26-tone RUs or larger RUs.

RU allocation policy Latency first Balanced Throughput first Latency-first fits small urgent packets first; throughput-first gives larger flows priority.

Teaching TXOP duration

5 ms

This is a simplified time slot for comparison, not a Wi-Fi standard constant.

Include trigger/ack coordination overhead in the teaching estimate

Dense IoT classroom

Current OFDMA PPDU Resource units fill from left to right in a simplified channel map.

TXOP 1

Turns needed 0 vs 0

Legacy turns compared with scheduled turns.

Average wait 0 ms

Queue wait estimate for HE clients.

RU fill 0%

How much of the teaching tone budget is assigned.

Clients left 0

Stations waiting for a later TXOP.

Diagnosis

What the current schedule teaches

These cards connect the visual allocation to latency, capacity, mixed-client behavior, and PHY guardrails.

Formula trace and guardrails

The numbers below are a teaching model. They compare queue turns and RU fit without claiming a full 802.11ax PHY-rate calculation.

Readout	Teaching formula	What it means

Quick reference

RU sizes

Common RU sizes include 26, 52, 106, 242, 484, and 996 tones. A 20 MHz channel maps to one 242-tone budget in this simplified display.

Uplink OFDMA

The AP sends a trigger frame so selected stations transmit together. Without coordination, the clients would contend separately.

Best fit

OFDMA helps most when many clients have short packets. It helps less when one large flow needs most of the channel or when legacy clients dominate.

Guided practice

1. Shrink the channel

Set the channel to 20 MHz with 24 tiny sensors. Watch the scheduled count and remaining clients.

2. Add legacy clients

Increase legacy clients to 8. The OFDMA TXOP can still be efficient, but the overall comparison includes more full-channel turns.

3. Switch to media traffic

Use the Cameras and dashboards mix. Larger RU requests reduce the number of clients served in the same TXOP.

Technical accuracy notes

Not a PHY-rate calculator

Real throughput depends on MCS, guard interval, spatial streams, coding, preamble, aggregation, channel conditions, and retransmissions.

RU maps are constrained

The display uses tone-budget arithmetic for learning. The IEEE RU allocation tables define exact legal combinations for each PPDU bandwidth.

OFDMA is scheduled

OFDMA does not remove contention from the whole network. It improves efficiency inside scheduled multi-user transmissions.

Sources

Primary and technical references

Use the IEEE and Wi-Fi Alliance sources for the standard and feature framing; the vendor guide gives accessible RU examples for classroom review.

IEEE 802.11 standards page

Official IEEE 802.11 working group standards list, including the IEEE 802.11ax high-efficiency amendment lineage.

Open IEEE source

Wi-Fi CERTIFIED 6 release

Wi-Fi Alliance launch material describing OFDMA, uplink/downlink multi-user operation, TWT, and dense-environment goals.

Open Wi-Fi Alliance release

Cisco Meraki Wi-Fi 6 guide

Accessible technical explanation of OFDMA resource units, channel widths, and maximum users per channel example.

Open technical guide