Welcome to our
new WiFi Ninjas Podcast episode!
In this episode Mac and Matt discuss at a high level how they design WiFi for the warehouse as they look to share their personal experience and tips with you.
Design recap (see episode 12):
- Understand the purpose
(data, high density, voice, scanners, etc.)
- Capture success
criteria (capacity, coverage, other RF elements, roaming)
- Always go on site
before and after (attenuation, RF condition, interferers, DFS, visual check)
Warehouse design challenges:
- Often very high
ceilings
- Moving forklift trucks
knocking off APs and antennas
- Changing stock
- Amazing WiFi during
holidays season can go ‘tits up’ before Christmas
- Changing racks layout
- Matt can say something
about it 😉
- Changing requirements
and purpose
- Those scanners from
1999 might now be upgraded and need to support voice
- Tons of obstructions
- Legacy devices
- Tendency to use old
scanners forever
- Weird devices
(especially true for legacy ones)
- Using specific
channels only
- Limited 5GHz channels,
in most cases UNII-1 only
- Using specific data
rates only
- AP tries 54, fails,
tries 48, fails, (…), settles on 2 Mbps – difficult to tshoot
- Battery operated
devices with failed implementation of battery saving mechanisms
- Doesn’t roam properly
or quickly enough
- Preferred authentication
is often not supported
- Security team crying
about having to use PSK
- Can be difficult to
get to the AP or antenna if needed
Warehouse design essentials:
- Choose the right
antenna type for the job
- Cover what needs to be
covered
- Coverage on the ground
level, 15m up where the forklifts operate or both?
- Environment can
dictate antenna type
- Omnidirectional won’t
be great at 20m
- Overlapping can be substantial
with omnis in vast open spaces
- Not always possible to
put omni in the middle of the rack
- Think about the
config:
- Normally you’d have a
different SSID for WH offices and WH packing / production / shifting
- For WH offices design,
listen to our previous episode
- For WH production,
keep it simple
- Get to know the
devices you design for – sometimes warehouses use very capable tablets or a mix
or modern tablets and very old scanners
- Roaming (quick one!)
is extremely important
- Can you / should you
stick to PSK?
- Can you / should you
use just UNII1 and UNII2 channels?
- Watch the Tx power and
data rates
- Will you survive on
20MHz? Normally WH capacity needs are low
- Do you really need
those bells and whistles for often very limited number of devices?
- Bonded channels = more
interference = lower SNR
- RX-SOP can mean drop
offs mid roam for stickier
- Devices might not like
802.11v – clients don’t like to be disassociated and v sends client a
proposition to associate with other best AP, followed by a threat of
disassociation if STA doesn’t jump on its own and a big chunk of clients don’t
support it
- Devices might not like
802.11r at all or some flavour of it
- Even old scanners
normally support 802.11a and 2.4GHz is often noisy from both WiFi and non-WiFi
interference; stick to 5GHz whenever possible
- Mounting and
positioning
- Few examples:
- Patch or sector on the
walls, covering entire or most of the aisle, tilted down, pointing towards the
aisle’s end
- Sometimes one AP per
aisle is enough (up to 80-100m), sometimes two at both ends (more than 100m)
- Patch or sector cone
of coverage with antenna pointing down, antenna mounted to the ceiling, duct or
suspended
- Omni with external
antennas pointed up or down, mounted to the wall, beam or column, away from the
metal surfaces
- AP/antenna placed in a
heated or cooled Nema enclosure
- Ensure basic AP
redundancy – it’s not easy nor quick to replace one
- Most important after
coverage is no CCI / ACI and fast roaming
- Ensure speeding
clients, both human on forklifts and robots (have you seen automated warehouses
yet?), are associated with the AP you want them to be associated with and that
they roam where and when we want
Other standard considerations
- Distance to the switch
- PoE
- Mounting restrictions
- Obstructions, metal
- Other networks
- Interferers
- Vendor choice
- Architecture
Thanks for
listening and please don’t hesitate to leave a comment, feedback, subscribe or
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