Voice over WiFi design challenges in High-rise Elevator

[ichen]

We got a project to provide WiFi coverage (Voice over WiFi will be perfect) in elevator cars in a high-rise building. This is a 59 floor building with 4 main elevator banks - low-rise (1-19), mid-rise (20-37), high-rise (38-60) and freight elevator (1-61). 3 elevator cabs of each bank. The speed of high-rise elevators is around 20-40 miles/hr (20 m/s - 40 m/s). The building height is around 900 ft (15 ft/floor). 

AFAIK, there are three ways to deploy this WiFi coverage in elevator:

1. deploy AP in elevator lobby on each floor (close to elevator banks) - the elevator speed may cause issues for roaming/mobility
2. deploy high-power directional AP on the top or bottom of elevator shaft - the coverage distance is not enough
3. deploy AP in each elevator cab - the elevator traveling cable is limitation - the distance of Cat-5/6 cable is not enough; however, there are not many qualified fiber elevator traveling cables on the current market
4. proprietary wireless distribution network solution

Does anyone has any experience or recommendations for me? Any comments are welcome.

Thanks,

[M. Wisely]

We've been looking at this as well and I believe we know how to do it. I'll go some of your options.

1. We already had this in most lift areas and it is not effective, phones lose signal between floors

3. We're planning to go with this but instead of a 4pair network cable we're planning to use one of the telephone cables in the cable to the lift car and a couple of vdsl modems for connectivity and power in the lift car to provide power to one of the modems and the AP.

[ichen]

Thank you for your comments. BTW, first, the traveling cables are connected from elevator machine rooms on the top floor of each bank. on the other word, the traveling cable length will be around 300 ft for the low-rise bank; however, for high-rise bank, we are expecting around 900 ft traveling distance from the top to 1st floor lobby. So, the traveling cable length of both mid-rise and high-rise elevator are out of copper (Cat-5/6) range. Unfortunately, most of elevator engineers told us that optical fiber is not a good option on the current market. Though there are some fiber products are "elevator data communication" grade but I can't get confirmation by any elevator SME.

Those high-speed elevator will pass each floor less than one sec for those pass-thru floors (e.g. the 38 floor is the first stop of the high-rise elevators from 1st floor).

The VDSL modem solution sounds interested to me but I am not sure about far-end termination equipment. Do I need any DSLAM to terminate the VDSL modem sessions in my elevator machine room or building IDF/MDF? Can enterprise IT people handle the VDSL operation? Did you ever see anybody use this solution yet? Thanks,

[M. Wisely · Accepted solution]

Have a look at the products here for an example http://www.blackbox.co.uk/gb-gb/1521/Over-Twisted-Pair.

The modems work back to back, no need for a DSLAM.or IDF/MDF. They'll work at well over the 900ft you've specified.

We have a small number of DSL modems installed across our organisation (not in lifts) and they work really well.

[#5]

Do we have details on the Elevator vendor who worked this project? Any details on the regulations they had to abide by as such?

[Leo Laohoo]

Putting an AP outside the door is backwards.  The elevator door are made of metal and the elevator cars themselves are a metal shoebox.  

I think the most effective way is to provide an AP to every car and the challenge will be the link and PoE.   The three "banks" of elevators use the old system called "flying lobby" and this makes things simple.  Since the length of the three "banks" do NOT exceed 300 feet/100 metres, it is very possible to connect them using UTP cables. 

The freight elevator will be a challenge because it goes beyond 300 feet/100 metres.  For this, I'd recommend running a two/three pair of fibre optic OM3 or OM4.  The AP inside the freight elevator will need to have a media converter and a power outlet for the injector.