Video: Wireless 101

Video surveillance is a big money-maker for many integrators and that will trend will continue, as analog system saturation gives way to IP. And given the physical limitations of digging and trenching in many areas, fixed wireless broadband is often times the technology of choice for communications.

“Fixed wireless broadband is compelling versus trenching a parking lot or paying a recurring monthly bill to a cellular provider,” said Scott Imhoff, director of business development at Cambium Networks, Rolling Meadows, Ill. Fixed wireless broadband typically operates at 5 GHz, re-creating the Ethernet computer port.

“Think of it as a wireless Ethernet cable,” Imhoff explained. “Rather than burying cable, you have an RJ-45 jack that plugs to the camera or security sensor. The signal is beamed to an access point.”

An access point is a fixed, central location where all traffic from various sensors or cameras around a customer’s premises comes into.

“Any skilled wire technician will be able to install fixed wireless,” Imhoff continued. “The big difference is knowing how to waterproof outdoor connections. But it’s the same wire strippers, the same RJ-45s, the same surge suppression for lightening strikes.”

College campuses, enterprises and the military all use these systems, said Ian Torok, director of Technical Services at BearCom, based in Garland, Texas. Most often they are used to integrate connections within the campus or create connections from point to point.

Torok cites Dallas as a prime example. The city has a wireless 150-camera system that collects data into a funnel that is backhauled with OFDM (orthogonal frequency-division multiplexing) point-to-point systems to the main server, managed by the Dallas internal IT department. BearCom maintains the radio connection and the city maintains the IP connection.


Know your 802.11n

A security dealer getting started in wireless must know the 802.11 standard, especially 802.11n. With 802.11n there’s the whole package: speed, resiliency and quality of service. Today, 802.11n is pushing 450 to 600 MB speeds. Experts say that, in a few years, 802.11 will reach Gigabit speeds.

“A security dealer should lay out what they want to accomplish: How much bandwidth is needed? How big is the network? How much data is there?” Torok said. Product is deployed based on those computations.

What about Wi-Fi as opposed to 802.11n? Wi-Fi is best-effort Internet access and is great for reading email at Starbucks. Security dealers do not want it for fail-safe applications. The 802.11n communications is a more robust protocol that allows high-speed transmission at longer distances and can trade speed for distance or vice versa.

“Before implementing a wireless system, a link analysis should be done on the proposed locations and path to determine the probability of success of the connection,” Torok said. The analysis determines where dishes need to be placed. A wireless provider can manage the analysis.

The 802.11n protocol also gives integrators speed without requiring more spectrum. It uses spatial multiplexing (SM) to split data into pieces. It then sends each data piece on parallel “spatial” channels—much faster than it would take to send that same data serially. Without SM, 802.11n can achieve 150 Mbps. With SM, it can hit 300 or 450 Mbps if both the transmitter and receiver have at least two and three antennas (and RF chains), respectively.


Terminology and nomenclature

In telecommunications, a point-to-point connection refers to a wireless connection between two antennae that beam signals to one another, Torok explained. “Wireless systems have a low probability of being intercepted, as it is nearly impossible to decrypt a point-to-point system,” he said.

Two types of wireless networks are popular: Microwave links use high-powered transmission that ranges from 1 GHz to 30 GHz in frequency, depending on how far the communication must go. “This is a very popular backhaul technology used for voice,” Torok said. Microwave systems are transparent to the user. They provide a secure connection for private enterprises. OFDM is the most popular connection for data transmissions. It is a strictly IP-based technology that is easy to align and configure. OFDM is a private IP-based option that ranges from 0 to 80 GHz, similar to microwave links.

“Both types of wireless network provide a private connection that transfers data without a monthly fee to a telco. You own it. You manage it,” Torok said. The major cost is for a radio and antennas.

Fixed wireless has a range from 100 feet to 10 or 15 miles—the latter most commonly needed by municipalities or railroads. Unlike the 300-foot limit with Ethernet, wireless can bring a video signal a great distance as long as there is AC power available—say from a street light—at the source.

Design help for wireless systems is readily available from manufacturers and providers. “You are not out there alone,” Imhoff said, noting that wireless vendors are happy to provide support.

In addition to basics like training, Imhoff said a security dealer should look to a vendor for a reliable, robust wireless product with low MTBF (mean time between failures). It should work well in a “noisy” environment that may include sources of interference, should be durable and weather-resistant. It must be easy to install. For video applications, latency should be as low as possible to minimize jitter (frequency displacement of the signal) on the video stream. Quality of service is important. Be sure product is available from multiple distributors to protect yourself and your customers in the event devices need to be replaced.

“It’s all about the value proposition,” Imhoff said. A grocery store might want to monitor its parking lot. Cameras mounted on light stanchions would work great. But the store does not want to trench its blacktop. And the customer is balking at the price of LTE data nodes or EBDO cellular. While the cost of a cellular modem is cheap, the fixed monthly charge from the provider can be cost-prohibitive.

“It can be ideal to do a wire line with lower costs upfront,” Torok said. But with fixed wireless, that customer makes a one-time investment in an access point—which can handle up to 200 remotes either outside or indoors. “Many enterprises choose to spend more money upfront to invest in a private infrastructure for a point-to-point wireless system,” Torok said. He agreed that trenching a line and running cable is a far more expensive option.

Fixed wireless broadband can support other traffic and gives business continuity backup in case the main network fails.

Imhoff said dealers should budget about two hours to deploy an access point to a rooftop. A remote module on a video camera or security sensor takes an hour to install, including cabling and surge suppression.

Installing point-to-point connections removes telco responsibility. A wireless provider can come in and manage the system. The dealer challenge is the installation process. An understanding of the connection is necessary, Torok said.

Imhoff typically sees a break-even of less than one year on fixed wireless. The access point is the most expensive piece. The more nodes it serves, the more cost-effective it becomes. At a campus or municipality with many nodes, the business model becomes compelling.

“It’s transparent for the customer,” Torok concluded.




Curt Harler is a freelance writer who covers technology and a regular contributor to SD&I magazine. He can be reached at