Real-Time Location System Design for a Big Airport in Africa

 

My latest, and most exciting, project has been to design a Real-Time Location System (RTLS) for a new big airport in Africa. This was no easy task.

My main challenge was in the diversity of spaces, the cluster of walls and the scale of the project. With a tight schedule at hand, you can't simulate the entire airport. So, I selected 4 random, yet different, locations where the ceiling height, cluster of walls and the number of people connected differed. Luckily, after simulating these 4 areas, I came to the following conclusions when it comes to access points spacing:

1) A 12-15 meter spacing would be sufficient for areas where walls are clustered.

2) A 25 meter spacing would be sufficient for an open and double height space with the presence of high number of users.

3) A 30m spacing would be sufficient for a normal open space area and the presence of a high number of users. 

Choosing one huge area containing the above mentioned space diversity, using Ekahau 9.1 and 802.11n/ac access points, the results were highly satisfactory: 

The Space:

Space data: Area (6,467 m²)

Coverage Requirement: Location Tracking (RTLS)	Signal Strength Min -65.0 dBm  Signal-to-noise Ratio Min 22.0 dB  Data rate Min 15 Mbps  Number of Access Points Min 3 at min. -65.0 dBm Channel Overlap Max 5 at min. -80.0 dBm Round Trip Time (RTT) Max 300ms  Packet Loss Max 5.0 %
Capacity Requirement	1200 Generic Smartphone [Very High SLA (10 Mbps)] 120 Generic Laptop [File Sharing, Normal (10 Mbps)] 120 Generic VoIP Phone [Very Low SLA (256 Kbps)] 250 Generic Tablet [Normal SLA (2 Mbps)] Total: 1690 (13,700 Mbits/s)
Notes	Above capacity requirements were calculated according to the number of seats and offices

Signal Strength at 2.4 GHz:

Signal Strength at 5 GHz:

SNR at 2.4 GHz:

SNR at 5 GHz:

Network Issues (areas covered in yellow are mainly bathrooms and stairs, the ones covered in red are shafts):

We can confidently say a 95% satisfaction was achieved! I wish had the time to simulate the entire airport, but when tight on time, you have to find ways to achieve the best results possible with the least time and efforts. I'm personally happy with these results.

See you next time!

Edmond Shami