Fabien Girardin reports on some of the problems encountered with the Wi-Fi network at his university. While this is not totally unusual, the fact that his university displays what he calls Deficient WiFi Awareness Sign is quite significant. It is much more usual to see signs that announces the availabilty of Wi-Fi rather than its non-existence or non-availability. This shows that Wi-Fi is becoming in some places a commodity that is expected to be present. While it is in theory possible to fully cover an area with Wi-Fi connectivity, there is no such thing yet as guaranteed connectivity while using a wireless medium like Wi-Fi.
One of the problems with wireless communication systems like Wi-Fi is that they are more likely to encounter problems than a wired communication system. There is, in some ways, some “mystery” left on how radio frequency signals works that we still need to figure out if you want to get the perfect connection. Wireless signals are much more likely to suffer interferences and this is especially true for Wi-Fi which operates in an unlicensed frequency range.
In addition to other devices trying to access the Wi-Fi, microwaves, cordless phones, computer accessories and even building structures can disrupt a perfectly well configured Wi-Fi connection.
While the technology is seeing constant improvement, it is still complex to plan or even monitor the behavior of a wireless connection.
One of my lab colleagues did his master’s thesis on the problem of placing the wireless access points. The tool he designed made use of a extremely complex set of equations and high number of calculations to find near optimal solutions to the placement of the access points for a 80×60 meters floor plan, while setting several constraints in his model. So knowing how complex the placement of access points would be for a “simplified” floor plan, I can understand that the same exercise for a citywide coverage is far from trivial.
As I was going through the request for proposal for San Francisco TechConnect, I found the expectations for the San Francisco Wi-Fi network far from what I expected (they are located under the Coverage section (p 9))
- Outdoor coverage shall be provided for Basic and Premium Services for a minimum of 95% of all areas of the City. An area is considered covered under this requirement if a laptop, interface – can access the Network at the provisioned service level with no additional hardware required beyond the device’s standard wireless interface.
- Indoor, Perimeter Room coverage for the ground and second floors of a building shall be provided for Basic and Premium Services for a minimum of 90% of all residential and commercial buildings throughout the City. A building is assumed covered under this Specification if a device located in each Perimeter Room on the ground and second floor of the building can access the Network at the provisioned service level. This coverage requirement may be met by using a Wi-Fi interface built into a user’s device, a signal amplifier, a high-gain antenna and/or a dedicated Wi-Fi bridge or other type of CPE.
- Indoor, Perimeter Room coverage shall be provided for Basic and Premium Services above the second floor for 90% of all residential and commercial buildings throughout the City. A building is assumed covered under this Specification if all Perimeter Rooms on all floors of the building can access the Network at the provisioned service level.
The problem with these requirements, along with others in the San Francisco RFP, is that they are extremely hard if not impossible to guarantee . So, I wasn’t surprised tonight when they announced the results that Earthlink/Google the leading candidate only got a grade of around 65% for their proposal.
Earthlink/Google proposal acknowledge that they don’t fully comply with the above requirements and states in their proposal that
It is difficult in practice to achieve 90 to 100% indoor coverage with any wireless network above the second floor or for interior rooms. Cellular systems are a good example, and users have already become accustomed to moving around to find a good signal for such services. (p 63)
So while we wait for the perfect wireless system to be designed, we should keep moving around to find a good signal and plan for failure accordingly. Maybe Earthlink should start printing signs to post around town!!