Video: Wireless 101

Here's your primer on wireless communications

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