In this episode I want to talk about Hallway Design or lack of it. This was inspired by a #WIFIQ that Lee Badman threw out there. I’ll tell you now, I don’t like hallway design. What is Hallway Design?
In a #WIFIQ thread, Jake Snyder said, “There is a difference between sticking APs in the hallway and hallway design.” And that’s true. He makes a very good point. The former is the act of randomly placing them in the hallway in hopes that you get fantastic coverage for the users in the rooms.
Negatives of Hallway Wi-Fi
- Low SNR
- Coverage holes
- Negative RRM effect
- Not designed for capacity
- No one working in the hallway
- Transmit power set at the highest if manually configuring
- Channel overlap
- Poor roaming decisions
- Lots of omnidirectional APs in the hallway
Designing Wi-Fi With Hallway In Mind
- Plan on the number of APs that will be placed in hallway
- Important to help facilitate roaming
- Signal propagates far in the hallway
- Lower transmit power or use thresholds
- Number of APs that can hear each other will have a negative effect
- Consider RRM in the design
- Transmit power levels
- Set thresholds – don’t allow the AP to go too high or too low
- Place APs where the users are
- Higher SNR
- Better data rates
- Plan for roaming
- Wi-Fi calling now available, users will walk out of their workspace
- Use building obstacles to help attenuate the signal
- Use a proper channel plan
Links and Resources
- Podcast Topic Survey – www.cleartosend.net/survey
- What is SNR
- Article by Blake Krone – Love Thy Patch – Read it on Airheads, http://community.arubanetworks.com/t5/Technology-Blog/Love-Thy-Patch/ba-p/270937
Looking at Blake’s Love Thy Patch post… when I look at the alternating layout, I see inferior coverage: lower RSSI, larger areas of gray, which I’m concluding is RSSI < $some_preset_minimum. What about that 2nd image says "this will be the better experience"?
Blake’s post is really about decreasing CCI and using directional antennas prevent the tunnel effect. Just another way of doing Wi-Fi if the APs are in the hallway. It would depend on what kind of directional antenna you use.
Yes, coverage wise the 2nd image is superior. That design won’t work though, due to CCI and sticky clients. Thats why Blake uses patch antenna’s to create more specific cell’s and avoid CCI.
The best solution would be placing AP’s in-room but as you can read in blake’s post that not always possible.
I agree that sometimes AP’s in the room is not always possible but it is the ideal solution if that can be translated well with management and the people who hold the money 🙂