Warehouse IT: scanners, Wi-Fi and the WMS
A scanner that drops off the network in a distribution centre holds up an entire shift. The network that is fine for the office laptops upstairs is frequently not fine twenty metres away between the racking.
Warehouse wireless fails for reasons an office never sees: steel racking reflects signal, stock absorbs it, and a full warehouse measures completely differently from an empty one. Coverage has to be measured under real conditions, not modelled from a floor plan.
Scanners roam constantly and tolerate a weak signal far less well than laptops. Most complaints described as coverage problems are actually roaming, channel or transmit power problems, and those are configuration rather than hardware.
Fix placement, channels and power before buying more access points. In most surveys we run, that alone resolves the complaint.
Why a warehouse is not a big office
An office is a predictable radio environment: plasterboard walls, people at desks, devices that stay put. A distribution centre is none of those things. Steel racking reflects signal into places you did not intend and blocks it from places you did. Pallets of liquid absorb it almost entirely. A forklift moves a large metal object through the middle of the coverage every few minutes.
The most common mistake is measuring an empty warehouse. A hall that measures perfectly in July can be unusable in November when the racking is full, and by then the equipment has been bought.
Scanners roam, laptops sit still
A laptop connects to one access point and stays there for hours. A handheld scanner moves the length of an aisle in a minute and has to hand over between access points cleanly, repeatedly, all shift. That handover is where warehouse networks fail.
The usual cause is transmit power left at maximum. It sounds helpful, and it means a device clings to a distant access point instead of switching to the nearer one, so the signal degrades until the scan drops. Lowering power across the estate frequently improves scanning without a single new device.
What we check first
| Check | What we look for |
|---|---|
| Transmit power | Anything at maximum across a large hall, which prevents clean roaming |
| Channel plan | Neighbouring access points on the same channel, so throughput drops as you add more |
| Placement | Access points mounted where the cabling was easy rather than above the aisles |
| Client settings | Roaming thresholds on the scanners themselves, which are often left at default |
| Interference | Non-Wi-Fi sources: chargers, motors, and the neighbouring unit’s network |
Cold stores and outdoor yards
Two environments deserve separate treatment. A cold store condenses, so equipment needs enclosures rated for it and the mounting has to survive temperature cycling. An outdoor yard has no ceilings to mount to, weather to survive and often a legal boundary to the coverage.
Both are solvable, but neither is solved with the same access point specification as the picking hall. Getting this wrong is expensive because the failure appears months later.
The WMS is part of the network design
A warehouse management system decides how tolerant the operation is of a brief interruption. Some hold state on the device and reconcile afterwards; others lose the transaction. That difference determines how much you should invest in redundancy, and it is worth establishing before the network is designed rather than after.
Where a landscape includes SAP or a sector-specific WMS, we take its change calendar and its supplier into account. It is our job to work around it, not to treat it as somebody else’s problem.
Work around the shift, not through it
Much of the work happens at night. That is not a reason to avoid change windows; it is a reason to plan them properly. We schedule around the shift pattern, verify before the shift starts rather than after, and keep a rollback that has actually been tested.
Cover outside office hours is worked as a shift by our own people, which means a night shift reaches somebody awake. What that covers is described under transport and logistics, and the measuring method under Wi-Fi analysis.
Questions we get about this
What logistics managers ask when scanning starts dropping.
Why do scanners drop when laptops work fine?
Because scanners move and laptops do not. A scanner has to hand over between access points repeatedly during a shift, and that handover fails when transmit power is too high or the channel plan overlaps. It is usually a configuration problem, not a coverage one.
Do we need more access points?
Often not. In most warehouse surveys we run, the biggest gains come from lowering transmit power, fixing the channel plan and moving a handful of units above the aisles. We say when hardware is genuinely needed, and we say when it is not.
When should a warehouse be measured?
Under realistic stock conditions, and again after any change to racking or layout. A hall measured empty tells you almost nothing about how it behaves in a busy season, which is exactly when the failure matters.
Can you work during our night shift?
Yes. Cover runs to your shift pattern rather than office hours, with nights and weekends worked as a shift by our own people, so a change window at three in the morning is staffed rather than on call.
Where this lands in our work
Where logistics work sits.
Want this looked at for your own sites?
Half an hour on a call is usually enough to tell you whether we are the right party for it, and we will say so if we are not.