Designing Cells in a High User-Density Area

[lbadman]

I need to design radio cells to service what for us is a challenging area. We have several adjacent classrooms and lecture halls, each expected to have a peak user load on the wireless network of 50-75 users. These users will have a mix of client cards- we cannot restrict them to Aironet cards only, but the APs are exlusively 350s and 1200s. The first thought to accomodate this high concentration of users is the "load balancing" feature touted in the AP product literature, unfortunately it only works with a 100% Cisco equation (APs and NICs have to be Aironet to be able to operate a load balancing cell of 2 or 3 APs on different channels for greater aggregate bandwidth). Also, I can't seem to get the cells small enough even at the lowest power setting to build 2 or 3 cells per room (this also gets into the realm of cost-prohibitiveness). Any thoughts or ideas? No LEAP, No WEP. Need to stay in 802.11b and Aironet 350/1200 framework.

[blue.modal]

Location-based load balancing can be forced by adjusting signal strength.

We've had the same problem with lecture halls - Cisco's answer for load balancing didn't address our requirements, so we configured the APs for 'de facto' load balancing by adjusting the signal strength.

In one 300 seat space, we had to put the APs behind the stage, but we put patch antennas on either side of the space. The resulting signal loss gave us just enough range from each antenna to ensure that users would connect based on where they sat, but if one AP failed they would still get a connection from the other. That still left us with the front and back walls for additional APs if user count increased.

If you need help engineering for a specific short or long range, let me know.

Matthew Wheeler

Chief Wireless Architect

www.BlueModal.com

[bmcmurdo]

To create a higher density of APs to cope with heavy usage you have 3 paramaters that can be configured;

1. Output power (can be set to as low as 1mw)

2. Data Rate (the higher the data rate the smaller the coverage area)

3. Antenna (directional antennas, or using the RF cable length as a source of signal anttenuation)