Battle of the Bandwidths

4.9 GHz is a clean, clutter-free spectrum that can support mission-critical public safety applications.


4.9 GHz is a clean, clutter-free spectrum that can support mission-critical public safety applications.

Terrorists are spotted building a weapon of mass destruction in an abandoned airport hangar. SWAT arrives on the scene. Utilizing a 4.9-gigahertz (GHz) broadband WiFi network, video is streamed to the commander from cameras deployed around the incident. From the command post, using a 360-degree view of the scene, he develops a strategy to enter the hangar, diffuse the weapon and nab the terrorists. One of the fleeing suspects commandeers a fuel truck and rams it into an airliner, setting it on fire and injuring the passengers and crew. Police, fire and EMS teams respond, coordinating their activities using interoperable broadband WiFi networks and applications.

This was the scenario at a Department of Homeland Security (DHS) Training and Evaluation Exercise in April 2006 at the Long Beach (California) Airport. Twenty-eight police, fire, EMS, military and government agencies responded to the hypothetical threat, which demonstrated the need for advanced, WiFi-based, interoperable communications systems.

September 11, 2001, Hurricane Katrina and the bombings in London, England, demonstrated what happens when communications systems fail - coordination among responding agencies becomes difficult or impossible. When radios fail, first responders reach for their cell phones. When cell phones fail, first responders' lives are placed at risk, and protecting the public becomes a daunting task.

Dealing with terrorist threats, gangs or natural disasters - as well as day-to-day law enforcement activities - demands new communications solutions and is fueling the development of broadband wireless networks. These networks enable law enforcement to better protect the public and themselves.

Broadband communication dramatically improves the efficiency of public safety organizations - and can result in actual cost savings. Long Beach highlighted how incident commanders can utilize video from multiple perspectives to gain a 360-degree view of an incident, from one location. Resources can be deployed using mapping and white boarding applications to provide clear, concise instructions. Video also can provide virtual back-up to officers on patrol - providing the watch commander with a view of a traffic stop or police activity in the field.

What is a broadband WiFi network?
WiFi networks connect a device (or node) to the network (represented by an access point) using radios. Some WiFi networks also enable client-to-client connectivity in one hop. Broadband wireless networks support higher bandwidth applications, beyond voice and simple data capabilities provided by standard radios or cell phones. With broadband, commanders can share large multimedia files, such as video and GPS mapping in addition to voice.

Broadband WiFi networks come in many forms, but share common characteristics:

  • They're based on Internet Protocol technology for digital (versus analog) communication;
  • Most require an access point to provide Internet connectivity and backhaul;
  • Most utilize meshing technology, creating a self-forming multi-faceted network; and
  • Most utilize unlicensed radio frequency spectrum to carry information.

It's this last point that presents a challenge for law enforcement. Spectrum refers to the frequency and bandwidth allocated to various forms of communications - including television, AM radio, microwave, radar and WiFi. In the United States, IEEE 802.11-standard based networks (commonly called WiFi) operate in the 2.4-GHz and 5.0-GHz bands. [Hereafter references to the 2.4-, 5.0- and 4.9-GHz bands will not include the "GHz."]

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