Despite the wide range of options for wirelessly connecting video surveillance cameras, video professionals agree on one thing. Where it is feasible to use a wired solution, integrators should choose that option, they say. As John Estrada, CEO of Cernium, explains, “If you already have wiring, you should use it; it’s more reliable.” Cernium is a Reston, Va.-based video camera manufacturer that does business as CheckVideo and offers both wired and wireless products.
There are times, however, when one or more cameras need to be installed in an area in which it would be difficult or impossible to run wire.
One commonly used option for wirelessly connecting video cameras is WiFi. Originally developed to enable laptop computers to connect to local area networks and the Internet, the technology also has found its way into some video surveillance cameras. Alternatively, cameras designed to communicate using IP can be plugged in to WiFi or other wireless equipment, although camera manufacturers may recommend the use of specific products from specific manufacturers for this purpose. At least one manufacturer — Cernium — also makes a gateway that wirelessly communicates images from up to four analog video cameras that are plugged into it.
One advantage of WiFi is that business customers often have already installed wireless LANs, minimizing the amount of investment the customer must make to support wireless camera connectivity. If dealers choose this option, however, they should consider establishing a virtual local area network (VLAN) for the video traffic, advises Edward Wassall, chief technology officer for Samsung Techwin America, a Ridgefield Park, N.J.-based WiFi equipment manufacturer.
“There are meters and tools that dealers can use to gauge how full the network is today,” Estrada describes. “You can do an analysis to determine if it will be able to handle the additional level of traffic.”
There are three different WiFi standards that are commonly used for video surveillance, all of which operate in unlicensed spectrum bands. Two of the standards — 802.11b and 802.11g — operate in the 2.4 GHz spectrum band. Equipment supporting the 802.11b standard supports a maximum data throughput rate of 11 Mbps, while 802.11g equipment transmits data at rates as high as 54 Mbps. The third standard — 802.11a — operates in the 5 GHz spectrum band and supports data rates up to 54 Mbps.
Where systems integrators have a choice of which type of WiFi to use — such as when they need to install a new WiFi network — they should seriously consider equipment operating at 5 GHz, advises Ebony Huang, CEO of Brickcom Corp., an Anaheim, Calif.-based manufacturer of WiFi and other wireless video cameras. The 2.4 GHz spectrum band is “nowadays widely used” notes Huang and may be “too noisy for video surveillance.”
It’s important to note that the 11 Mbps and 54 Mbps WiFi throughput numbers are maximum numbers. WiFi networks typically provide less bandwidth; the more interference encountered from other devices operating in the same band, the less throughput a network will support.
How many video cameras an individual WiFi access point can support depends on a variety of factors, explains Vince Ricco, North American business development manager for the technology partner program at Chelmsford, Mass.-based video camera manufacturer Axis Communications. These include the frame rate, the camera resolution and the type of compression used.
Ricco offers his advice on how to minimize bandwidth requirements without compromising quality. The human eye perceives motion at the equivalent of about 17 frames per second, Ricco explains. He notes, though that, “It’s hard to perceive the difference between seven frames per second and 17 frames per second from a loss-prevention standpoint.” Depending on the distance between the subject and the camera, VGA resolution should provide sufficient clarity, Ricco asserts. If the background of the image is not constantly changing, Ricco recommends H.264 compression, which “only captures changes in the field of view.” Motion JPEG compression, on the other hand, refreshes each frame in its entirety, he says.
Wassall says he’s never seen more than four cameras work effectively on a single WiFi access point at 5 GHz. At 2.4 GHZ, he suggests dealers use no more than “one or two, tops.”
One way to minimize the amount of bandwidth required for video transmission is to store video on the camera itself and to stream images only when the system senses motion. That’s the approach that CheckVideo uses for its wireless video cameras, which use a combination of WiFi and cellular connectivity to stream a 10-second clip to a remote data center only when motion is sensed. With CheckVideo’s sytem, however, authorized end users are able to check in on cameras whenever they want to — and as Estrada notes, that option requires considerable throughput.
WiFi equipment, like other equipment operating in unlicensed frequency bands, may be subject to interference from other devices operating in the same band. Accordingly, its range is less than for some other wireless options. “Outdoors you can probably get 1,000 to 1,500 feet if there’s not a lot of blockage,” Estrada notes. “Indoors, if it’s placed properly you can probably get 30 to 50 feet down a hall.”
Alternatives to WiFi
Alternatives to WiFi for transmitting surveillance video include licensed and unlicensed options.
On the unlicensed side, San Diego-based MicroPower Technologies offers equipment that operates in that same 2.4 GHz band yet claims considerably more range — half a mile using line-of-sight transmission, according to CEO Jon Siann. As he explains, the company’s equipment is able to achieve that because it avoids data collision with other devices because it is “aware of what’s going on.” Each MicroPower hub can support four to six cameras and as many as three hubs can be installed in the same area, Siann states.
Another notable aspect of the MicroPower solution is that it does not require power to each camera, but instead is solar-powered. “The real innovation is that we have reduced power consumption to a level where solar power becomes practical,” Siann explains.
Boston-based Fluidmesh Networks offers wireless equipment at several licensed and unlicensed frequency bands that uses a proprietary transmission protocol and can be used with video cameras or access control readers (see related article, “Wireless Options in Access Control” on page xx). The equipment can be installed in point-to-point or point-to-multi-point configurations.
A third option is a mesh configuration, which according to Cosimo Malesci, Fluidmesh’s vice president of marketing, is the wireless equivalent of a fiber loop. Communications are transmitted from one camera to another to the head-end, adding redundancy to the system.
Licensed options are popular primarily with municipalities, which want the extra throughput they allow, Malesci says. The number of users at licensed frequencies is controlled through the licensing process, minimizing interference problems and enabling users to transmit at higher power levels. Malesci notes, though, that licensed options can cost 10 times as much as unlicensed options.
Another company that offers a licensed option for wirelessly transmitting video images or access control data is Orlando, Fla.-based Parseous Systems. The company uses spectrum in the 217-220 MHz band, which years ago was divided up into a large number of narrow channels intended for voice communications in industrial settings. Parseous has developed technology that aggregates up to 40 of these channels, which do not have to be contiguous, in order to support higher bandwidth communications over distances as great as nine miles, explains Parseous’ president and CEO, Brian Andrew. He cautions, however, that video cameras should not be set up for continuous streaming, but instead should transmit video only when motion is detected.
Customers must purchase licenses for every base station used, but each license costs just $100 for 10 years, Andrew says, adding that the signals are able to penetrate trees and other objects that might block other types of radios.
Some manufacturers also have begun to offer wireless equipment that works over cellular radio networks. The challenge with these systems is that traditional cellular rate plans are designed for consumer data and voice communications, which may not be appropriate for communications required for video and access control.
Ricco notes, however, that wireless network operators are beginning to recognize that they may need to develop special rate plans for the security industry. “They’re still grappling with it,” Ricco observes. “They’re talking to us.”
Extending the Distance Between the Reader & the User
One area of access control where wireless has been widely used for many years is in the interface between the reader and the credential. Typically this is accomplished using short-range communication based on RFID. But sometimes a customer needs more range.
Sunnyvale, Calif.-based manufacturer Farpointe Data offers a product designed to enable drivers to gain entry through parking gates and to communicate the driver’s identity wirelessly to the access control reader. As Stephen Sheppard, director of sales for North America for Farpointe explains, the product operates at 433 MHz and has range as great as 150 feet.
Licensed or Unlicensed?
Downers Grove, Ill-based security dealer Current Technologies Corp. does many large-scale surveillance video installations.
“Our niche is wireless,” explains Current Technologies’ President Steve Daugherty, who notes that municipalities often opt for wireless because they can avoid the cost of trenching wire and they like the option of being able to equip police cars with video.
Current uses cameras from Axis Communications with wireless equipment operating at licensed and unlicensed frequencies. As Timm Erk, senior wireless network engineer for Current Technologies explains, some unlicensed frequencies can be “saturated” in some areas — and when that situation exists, a licensed alternative may be a better option.
The licensed frequencies that Current Technologies primarily relies on are between 6 and 38 GHz. “The higher the frequency, the more bandwidth and throughput you have but the shorter the distance you can travel,” Erk explains. At 38 GHz, signals travel about one mile, while at 6 GHz, signals travel about 50 miles, Erk says.
Wireless Options in Access Control
Although many security professionals advise using wired over wireless options for surveillance video wherever possible, it’s not quite the same when it comes to access control.
Transmissions from access control readers require considerably less bandwidth than streaming video. And according to Karen Keating, portfolio marketing manager for Carmel, Ind.-based access control equipment manufacturer Ingersoll Rand Security Technologies, wireless access control readers can be less costly to install than wired alternatives. “The cost savings is ultimately in labor,” Keating explains.
Ingersoll Rand is one of several manufacturers — including New Haven, Conn.-based ASSA ABLOY — that offer wireless card readers that are built into door locking hardware. Traditionally both of those devices would have been separately wired. As Garrett Lovejoy, product manager for electronic access control for ASSA ABLOY explains, dealers often have to call in additional tradespeople to handle certain aspects of those installations. With the new solutions, dealers can handle the entire job on their own, Lovejoy says.
ASSA ABLOY’s wireless access control reader/lock uses WiFi for communications, minimizing the investment required, Lovejoy says.
Ingersoll Rand’s wireless readers operate in the 900 MHz band which, according to the company, has good signal propagation and strength, enabling transmissions to penetrate building walls. A wireless module capable of connecting wirelessly with up to 16 devices is hardwired to the panel, communicating with the panel using RS485.
As an alternative to wireless reader/locks, some companies — including Lapeer, Mich.-based Cypress Computer Systems — offer wireless equipment that connects to Wiegand devices such as readers and gate controls.
“Everything that traditionally would be wired from the portal would come through our interface,” explains Cypress President Paul Ahern. “We’re kind of a transparent Wiegand solution.”
Cypress offers equipment operating in the 900 MHz band primarily for outdoor use or in the 2.4 GHz band primarily for indoor use. But although the 2.4 GHz band is also used for WiFi, Ahern says the Cypress equipment isn’t based on WiFi.
Cypress products also support mesh communications, enabling one radio to act as a repeater for another so that they can be used in installations where it would not be possible to obtain line-of-sight communications between the reader or gate control and the access point.
Wilmington, Mass.-based security dealer Surveillance Specialties prefers to install wireless access control readers because they are easier to install than their wired counterparts, notes Brendan Daley, director of the company’s doorframe and hardware division.
“Door to door, the cost should be less,” Daley observes. Surveillance Specialties uses wireless readers from ASSA ABLOY, and Daley says installation costs typically compare favorably with wired alternatives even if the customer does not already have a WiFi network.
Not everyone agrees that wireless should be used routinely on access control jobs. Branson, Mo.-based dealer Tuxen Integrated Systems, for example, chooses wireless primarily to avoid long cable runs.
“If you have to go several thousand feet, wireless will be a lot more cost-effective,” comments Gorm Tuxen, president of Tuxen Integrated Systems, which uses wireless equipment from Cypress for those installations.
Ingersoll Rand offers a wireless device that combines an access control reader, electronic door lock and request-to-exit switch.
PHOTO COURTESY OF INGERSOLL RAND