A very quick question:
- Which of the current crop of indoor mobile coverage options offers the best chance of working during emergencies, for voice and/or data?
Historically, landline phones have been fairly reliable as the lines are powered from the exchange (unless it's via a locally-powered PBX or home cordless unit), and have a direct physical metal connection exiting the property through the wall.
Conventional macrocellular 2G/3G phones and networks have also been to individual buildings being affected, although city-wide events such as terrorism and earthquakes have caused congestion or failure. The use of GSM or CDMA in 850-900MHz and 1800-1900MHz bands has tended to mean reasonable indoor coverage.
But I'm wondering if newer solutions such as WiFi, femtocells and even active distributed antennas & repeaters are more vulnerable, as they are reliant on local power from electrical sockets and the in-building LAN wiring and infrastructure.
I'll readily admit that this isn't a focus area of mine - but with the advent of technologies like LTE & WiMAX running in high-band frequencies like 2.6GHz, reliable in-building operation surely becomes much more of an issue.
What are the knock-on impacts on both indoor build-out (UPS power for femtos?) and also specrum policy?
Dean Bubley's Disruptive Wireless: Thought-leading wireless industry analysis
2 comments:
One of the more reliable solutions for provision of indoor wireless coverage is a distributed antenna system. While it is true that these systems generally require local power, there are other power options which would enable them to operate even during an emergency power outtage. Most of these systems can be supported by uniterruptible power supplies (UPS) which use batteries to provide up to 8 hours of service. In addition, many DAS systems can be fed with DC power, and actually can be connected to the same batteries which are used to back-up the associated basestation.
Dean
This was one of the biggest questions in the U.S. broadband plan approach to public safety. It didn't get any publicity, but there is a strong recommendation that essentially all major buildings have an indoor femto or WiFi system, presumably with good battery backup. The strongest voice actually was a fellow who did the analysis after the trade center fell.
I don't have time right now, but if it's interesting I'll provide more information and contacts. Just ask.
Post a Comment