Corporate Wi-Fi installation: from survey to sign-off

Most enterprise Wi-Fi problems are installation problems, not product problems. This is the sequence that avoids them.

1. Requirements, in writing

Before anyone opens a design tool, agree and document:

Applications that must work, and their tolerance for loss and jitter.
Device inventory, including the oldest and cheapest thing that must connect. That device sets your floor.
Coverage areas, including lifts, stairwells, plant rooms, loading bays and car parks — and explicitly the areas that do not need coverage.
Roaming requirements. Does a voice call need to survive a walk from reception to the third floor?
Security and segmentation model, and who owns the RADIUS infrastructure.
Physical constraints: listed building, exposed services, ceiling type, aesthetic sign-off, out-of-hours access.

Unwritten requirements become change orders.

2. Predictive design

Model the floor plan with real wall materials. Default material libraries are optimistic. Calibrate them if you can: measure attenuation through a representative wall with a signal generator and a survey tool, and correct the model.

Output should include AP positions, mounting heights, antenna types, channel plan, power levels and predicted coverage per band — including at 6 GHz, which is the tightest constraint.

3. Active validation survey (pre-install, where budget allows)

Place a single AP at a proposed location and measure. An AP-on-a-stick survey in three or four representative locations validates the model cheaply and catches material assumptions that are wildly wrong before you install eighty access points in the wrong places.

4. Cabling and power

Cat6A as the default for new installations. Cat5e will carry 1 Gbps and works today, but Wi-Fi 6E and Wi-Fi 7 APs increasingly want 2.5 or 5 GbE uplinks, and re-pulling cable in an occupied building costs several times what the cable costs.
Run two cables to each AP location. The second pays for itself the first time you need link aggregation, a second AP, a camera or an IoT gateway. The marginal cost during first fix is small.
PoE budget realistically. Wi-Fi 6E and Wi-Fi 7 APs frequently need 802.3bt (PoE++, Type 3, up to 60 W) to enable every radio and the 5 GbE uplink. On 802.3at (30 W) many APs quietly disable a radio or drop the uplink to 1 Gbps and never tell you. Check the AP data sheet's full functionality power figure, not its minimum.
Size the switch, not just the port. Forty APs at 30 W each is 1200 W of PoE budget before you count phones and cameras. Check the switch's total PoE budget and its redundancy.
Test every link with a certifying tester and keep the results. "It links at a gigabit" is not a test.

5. Mounting

Below the ceiling, in the open, wherever it is permitted.
Use the vendor's bracket and orientation. APs have designed antenna orientations; mounting a ceiling AP vertically on a wall rotates the pattern into the floor and the sky.
Never in a metal enclosure, never inside a cupboard, never above foil-backed insulation.
Label everything: AP name, switch, port, patch panel position. Put the label where a person on a ladder can read it.
Photograph each installed AP in place. This costs minutes and saves days.

6. Configuration baseline

Minimum data rate: disable 802.11b rates (1, 2, 5.5, 11 Mbps) entirely; set the minimum basic rate to 12 or 24 Mbps to shrink cells and speed up management traffic.
Band steering on, but verified — aggressive steering breaks some clients.
802.11k, 802.11v and 802.11r enabled for roaming, with 802.11r tested against your actual client mix before it goes live everywhere.
Airtime fairness on.
Multicast: convert to unicast or rate-limit. Unmanaged multicast at the lowest basic rate is a classic capacity killer.
Separate SSIDs kept to a minimum. Every SSID costs beacon airtime on every AP on every band. Three or four SSIDs maximum; use dynamic VLAN assignment via RADIUS rather than an SSID per department.

7. Post-installation validation

Walk the site with a survey tool on the live configuration. Verify:

Primary coverage against the target threshold at the highest band you rely on.
SNR at least 25 dB in primary coverage areas.
Overlap sufficient for roaming, but not so much that CCI dominates.
Roaming behaviour with a real device on a real call, walking a real route.
Throughput at several points, wired-to-wireless, in both directions.

8. Handover

The deliverable is not "the Wi-Fi works". It is: as-built drawings with AP positions and names, the channel and power plan, cable test results, configuration export, the validation survey, the AP photographs, and a short document explaining the design decisions — especially the deliberate ones, like why DFS is disabled or why 2.4 GHz is off in half the building.

Without that last document, the next engineer will undo your decisions within a year.