Beware, Location-Aware (FMC) Part 2

By Rich Watson

In my last blog, I talked a little about the shortcomings of location-aware technology, especially as it compares with DiVitas’ more flexible environment-aware approach to seamless roaming. We’re going to continue with this topic because of some recent questions we’ve received about the differences between location-aware and environment-aware technologies. For example, we were recently asked if a location-aware solution is better for organizations that want a detailed map of their environment for management purposes.

The answer? Creating a detailed map of your WLAN is critical for reliable mobile communications (especially one based on seamless-roaming), but tying that map to the “roam” itself is not a good idea. And here are 3 reasons why:

DEAD ZONES

Location-Aware: No matter how hard you try, there will always be dead spots (i.e., no coverage) within a WLAN network. These “dead zones” result from under-coverage (by design) or geometry of the facility that can shape (or misshape) the Radio Frequency (RF) environment. Because these areas do exist within a building or on campus, the Mobile UC application must be able to accommodate for this situation in providing the best voice quality.

With location-aware roaming, dead zones become a major problem because this technology doesn’t have the intelligence to roam to cellular when a phone passes through one of these dead zones. Roams that are solely dependent upon on location-based logic will fail because, in a dead zone, the current Access Point (AP) would have no associated location-mapping and the client would assume it was within a contiguous WiFi space. In this case, the WiFi signal could go to zero without a guarantee of cellular coverage and the call would drop. By the time you enter a “dead zone”, it’s too late.

Environment-Aware: In contrast, an environment-aware solution like DiVitas responds dynamically to changes in the RF neighborhood. It constantly monitors voice quality and will automatically roam to cellular-mode if the WiFi call degrades, regardless of the user location. Dead zones are not a problem in an environment-aware solution like DiVitas; they are just a normal cause to roam to cellular.

OVERLAPPING CHANNEL CONFLICT

Location-Aware: APs often experience overlapping channel conflict - an occurrence that happens when two APs configured to the same channel are located side-by-side. When this happens they can either null each other’s signal out or induce interference, blocking communication. Again, as with dead zones, a location-based solution is not able to roam to cellular when it experiences a loss of signal so the call will drop.

Environment-Aware: In contrast, an environment-aware solution such as DiVitas detects any loss of WiFi signal or degradation of voice-over-WiFi quality. In either of these situations, it will automatically roam to cellular. This means calls won’t drop.

Antenna Sensitivity

Location-Aware: Many location-aware solutions don’t properly account for antenna sensitivity differences between devices. This means one phone may pick up a WiFi signal that another phone cannot, and the phone with the weaker signal will fail to roam to cellular. Or it might roam at an inappropriate time … like when it shouldn’t. (Spending more time in cellular means more money spent on cellular minutes). This muddies the concept of location-aware roaming because the ability to receive the signal – and place or maintain a phone call – is dependant on where a person (with a handset) is standing in the building relative to an AP, and it depends on the RF-sensitivity of the device. Performing a location service with one device may induce undesirable handover behaviors with other devices…even from the same handset vendor.

Environment-Aware: In contrast, environment-aware solutions detect any changes in signal strength, and automatically roam to cellular when a signal is lost or call quality degrades beyond acceptable.

For more information on DiVitas Networks, please visit our website at www.divitas.com