Calling All Nodes
a&s International | Date:
We now live in a world where wireless technology has become a “way of life” for many. Traditionally considered a last resort in security applications, wireless transmission has come a long way in signal reliability and resilience — in some cases, it is even the only option.
“Where we're going, we don't need roads,” said Dr. Brown in the 1980s' blockbuster Back to the Future. While we are far from eliminating roads today, technology has allowed us to remove something comparable — wires.
Three key wireless topologies exist today, namely point-to-point (PtP), point-to-multipoint (PtMP) and multipoint-to-multipoint (MPtMP). The flexibility of mesh allows it to be deployed in many scenarios for complete redundancy, said Ksenia Coffman, Senior Marketing Manager at Firetide. “Some deployments start as PtMP and then are reconfigured into a mesh topology when security needs call for ubiquitous coverage later on. Some integrators deploy mesh equipment in a PtMP topology, with ‘mesh on the edges' to provide reach into remote areas.”
Where the Wires End,Life Begins
The Americas and EMEA regions' combined market for wireless infrastructure used in video surveillance was estimated to be worth around US$175 million in 2009, with an estimated growth rate of nearly 20 percent in 2010, according to IMS Research.
Wireless transmission for security is getting adopted across a broad spectrum of use cases, said Manju Mahishi
, Director of Wireless Products Strategy at Motorola Solutions. “Most notable is mass transit with trains and buses, where a wired network is not even an option, and perimeter security at large facilities, where wiring would be cost-prohibitive.”
Two of the key vertical markets with strong demand are government and public safety, Mahishi continued. “Other key markets for wireless mesh networks include manufacturing (such as petrochemical), transportation (airports, seaports) and construction (large sites/projects).”
“Three vertical markets where demand for wireless infrastructure for video is especially strong are government (city surveillance, homeland security, emergency preparedness, critical infrastructure), transportation (mass transit, railways, highway systems) and industrial (plants, construction, oil and gas, utilities),” Coffman added.
“Ease of deployment and low cost of ownership are the main advantages of using a wireless video surveillance system,” Mahishi said. “There are no disadvantages in using a wireless system if it is deployed correctly.”
For security applications, wireless transmission is often utilized in outdoor settings, where a wired infrastructure
is nonexistent, cost-prohibitive or impractical, Coffman said. “Wireless networks are also ideal for temporary installations from days (such as special events, fairs, rallies) to months (construction sites). Wireless installations are much faster and do not require major construction or cause the disruptions that fiber installations do. We've seen wireless deployed for indoor surveillance in cases where it's impossible to wire, such as monuments with historical value.”
Wireless is best suited for locations with established infrastructure such as roads, parking lots and buildings, where trenching is cost-prohibitive, added Jeremy Damato, Technical Support Manager at KBC Networks. “It's also a cost-effective solution for systems requiring remote transmission from locations that exceed standard cable limitations.”
Wireless networks for video surveillance must be reliable. A wireless mesh network typically utilizes the 802.11 standard and provides redundancy and multiple paths to ensure tolerance for failure of individual points within the network. “The advantage of wireless mesh networks is that redundant links eliminate single points of failure associated with conventional wireless networks, with multiple paths overcoming line-of-sight (LoS) issues,” Coffman said.
“Mesh systems allow for redundant paths in the event the signal is obstructed by a mobile object or if a competing device is turned on in the vicinity of the primary path,” Damato added.
Mesh networks are also designed to provide several different options, Damato continued. “Based on the radio integrated into the mesh node, the system can offer multiple frequency bands and networking parameters to better equip the system in harsh radio frequency (RF) environments. For this reason, wireless mesh systems are becoming more popular in traditional PtP environments, such as apartment complexes.”
“Today's multi-in-multi-out (MIMO, 802.11n) wireless mesh networks have already been deployed to support HD and megapixel video surveillance. One limitation compared to fiber continues to be throughput — wireless mesh is not yet capable of providing gigabit (Gbps) speeds,” Coffman said. “However, with up to 90-percent reduction in cost, this trade-off is often acceptable to our customers.”
Wireless mesh is essentially a companion technology to cellular broadband, Coffman continued. “For example, our customers build out mesh backhaul to connect the cameras (in lieu of fiber), and then use a cellular broadband technology to provide access to the feeds from the field (such as via cellular routers). So, the two technologies complement each other. To illustrate the point, wireless mesh provides 100 to 150 Mbps of user throughput per hop (essentially equaling wired Ethernet and approaching fiber). Cellular broadband, in contrast, provides an average of 5 Mbps for download and 1 or 2 Mbps for upload. Latency is also much higher in cellular broadband technologies.”