Planning office Wi-Fi: coverage, capacity and the right access points

Coverage or capacity: what office Wi-Fi really has to deliver

Office Wi-Fi should be planned for capacity, not just coverage. Coverage means the signal reaches every workplace; capacity means the network can serve all devices in a room at once with enough throughput and low latency. The real test is not full bars in every corner but a full meeting room in the middle of a video call.

In modern offices, capacity is usually the limiting factor: each person brings a laptop and a phone, often a headset or tablet as well. Planning therefore starts by asking how many devices will be active in each area and for what, such as video calls or point-of-sale systems. The survey, bands, access points, channels, roaming and security follow from that.

Site survey and heatmaps: measure before you mount

A Wi-Fi site survey turns floor plans and real measurements into a design, usually documented as heatmaps: colour-coded floor plans showing signal strength, signal-to-noise ratio and channel overlap. Three types are common:

• Predictive survey: software simulates the Wi-Fi from floor plans, wall types and planned positions; well suited to new buildings and budgeting.
• On-site survey: measurements in the building, often with a test access point, that capture real attenuation and neighbouring networks.
• Validation survey: a measurement after installation that proves and documents that the target values are met.

Many design guidelines use about -67 dBm or better as a target for areas with voice and video calls. More important than a single number, however, is a clear requirement for each area, from meeting room to warehouse.

Building materials make the difference

Plasterboard walls and wooden doors let radio waves through with little loss. Brick walls, especially the thick walls of older Viennese buildings, reinforced concrete, lift shafts, fire doors and metal shelving dampen the signal considerably, and coated low-emissivity glass can block Wi-Fi about as much as a solid wall. A survey reveals these effects before mounting, not after the first complaints.

2.4, 5 and 6 GHz and Wi-Fi 6, 6E and 7 in plain words

Lower frequencies travel further but offer fewer channels; higher bands offer more channels and throughput but a shorter range.

• 2.4 GHz: good range, but in practice usually only three non-overlapping channels and interference from Bluetooth, microwave ovens and neighbouring networks. Today mainly useful for older and IoT devices.
• 5 GHz: the workhorse in the office, with considerably more channels. Some of them require radar detection (DFS): if an access point detects a radar signal, it must leave the channel, which can cause short interruptions.
• 6 GHz: clean spectrum without legacy devices, available with Wi-Fi 6E and Wi-Fi 7. In Europe, the lower part of the band (5945 to 6425 MHz) is released for Wi-Fi, mainly for indoor use. WPA2 is not supported there; secured networks need WPA3.

The speeds printed on the box are theoretical maximums; what counts is how efficiently an access point serves many devices at once. Wi-Fi 6E or 7 is a sensible choice for new installations, but devices only use 6 GHz if they support the band.

Access point placement, density and channel planning

Access points belong on the ceiling, in or close to the rooms where people work, with a clear line of sight to the devices. Cupboards, corridors behind fire doors and positions above metal ceiling panels are poor locations. Large meeting and training rooms often need their own access point.

The number of access points follows mainly from capacity: several access points with moderate power serve a busy floor better than a few very strong ones. Neighbouring radio cells should overlap enough for devices to move between them without dropping the connection.

Channel planning

Neighbouring access points should use different channels; otherwise they share airtime and slow each other down. Use 20 MHz channels in the 2.4 GHz band. In the 5 GHz band, 20 or 40 MHz usually works best in dense offices; 80 MHz pays off where enough channels are free. Automatic channel selection helps, but check its results against the heatmap and neighbouring networks.

Roaming and security: WPA3 and a separate guest network

Roaming means a device switches between access points as its user moves through the building. Use the same network name (SSID) with identical settings on all access points and enable 802.11k, v and r, which help devices find the best access point and reconnect quickly. Test this with your own devices, as some older ones struggle with fast roaming.

For staff, WPA3 is the current standard. WPA3-Enterprise with personal credentials, checked by a RADIUS server linked to your directory service, is better than a shared password: when someone leaves, only their access is revoked. Older devices without WPA3 can use a transition mode or a separate network.

Guests and private phones do not belong in the office network, and IoT devices need their own segment. Give guests their own SSID in a separate VLAN with internet access only, client isolation (guest devices cannot see each other) and a bandwidth limit.

Cabling, PoE and monitoring

Every access point needs a network cable, which usually also supplies its power via Power over Ethernet (PoE). Powerful Wi-Fi 6E and Wi-Fi 7 access points often require PoE+ (IEEE 802.3at) or 802.3bt and may switch off functions if power is insufficient. Check the PoE budget of your switches and plan multi-gigabit ports where access points need more than 1 Gbit/s. Our article on PoE planning explains the calculation.

In operation, a controller or cloud management platform shows clients per access point, channel utilisation, interference and failed devices, and distributes firmware updates. Alerts for outages and a repeat measurement after renovations keep the Wi-Fi reliable for years.

Common mistakes and how to avoid them

• Repeaters instead of cables: a repeater with a single radio sends and receives on the same channel and can roughly halve throughput. Wireless mesh is only a fallback where no cable is possible.
• Planning by floor area only: a meeting room with 20 people needs more capacity than an archive of the same size.
• Too many SSIDs: every network name sends its own beacons and costs airtime. Two to four are enough for most offices.
• No measurement after installation: without a validation survey, nobody knows whether the target values are met.

Conclusion: Wi-Fi is planned, not just installed

Reliable office Wi-Fi is the result of planning: measuring instead of guessing, cables instead of repeaters, moderate transmit power instead of maximum values and a clearly separated guest network. If you are planning a new office or want to improve existing Wi-Fi, Q-entra supports you with network and Wi-Fi infrastructure from the site survey to ongoing operation.