Wireless: Where to deploy it

There are three scenarios in which wireless is preferable to wired, says Jeff Johnson, president of Videocomm, based in Oakville, Ont.

”¢ An area where it’s physically impossible to run cable, like across a busy street or in a historic building where drilling or cabling would not be permitted
Ӣ An area that would make cable too expensive, like covering a parking lot with security cameras
Ӣ An area where you want to maintain a clean appearance, i.e., no unattractive wires

Johnson says his end users tend to be schools, property managers, facilities, and parking lot operators. He has also sold to military, law enforcement, and even dentists.

For the technology to operate, it requires line-of-site. Unimpeded, wireless signals can travel for miles. Johnson says that 801.11n signals using orthogonal frequency-division multiplexing (OFDM) — an 802.11 end format, which allows us to transmit real-time video at high definition quality — might be able to travel as far as 64 km.

But most deployments won’t be a best-case scenario. Trees, buildings and other obstacles are bound to get in the way, at least over long distances. Indoors, Wi-Fi signals have to overcome barriers like furniture and office walls. Johnson says he can’t really predict how far a signal might travel without first assessing the situation ”“ every deployment is different and comes with different challenges ”“ but wireless signals are not unlike sound waves, he says.

“If you were singing happy birthday at the top of your lungs and I was in the office next door to you, I could probably hear the words. Three offices down the hall, I could hear you singing but not necessarily make out the words. Ten offices down the hall I could probably hear a noise but not know whether it’s singing or anything,” he says. The same is true of wireless signals.

Pipe down: bandwidth considerations

The main drawback to wireless camera installations continues to be bandwidth limitations.

 “Video is notorious for consuming large amounts of bandwidth ”“ two to three mbps using MPEG 4 per stream. That adds up quickly,” according to Michael Martin, a senior managing consultant at IBM Canada who has helped design wired and wireless networks (and those that integrate both).

Piping in Gigabit Ethernet is not a problem using more conventional wired security systems, he says. But with current Wi-Fi standards, “we might only get 26 mbps of net payload.”

The good news is that wireless networks are beginning to catch up. Where previous wireless protocols (such as 802.11b and 802.11g) have been met with severe limitations, 802.11n promises to level the playing field and could be the technology that allows users to move beyond Ethernet LANs.

Development of 802.11n slowed down last year due to patent issues, but experts believe it should be a workable standard sometime in 2009. The promise of 802.11n is “significantly better bandwidth ”“ up to six to 10 times greater than 11g,” says Martin. “As a result we might see bandwidth in the neighbourhood of 300 to 800 mbps.”

Until we reach that threshold, however, conventional wireless transmission means are still more than enough for some users, depending on their requirements. For example, 802.11g can still yield a maximum throughput of 54 mbps using OFDM (orthogonal frequency-division multiplexing).

Network security revisited

As previously mentioned, security is not necessarily an impediment to wireless CCTV. Provided the appropriate precautions are taken, it need not be any less secure than the majority of wired systems.

“The security issue used to be totally in favour of wired, but that’s becoming less of a concern because the IEEE and the IETF (Internet Engineering task Force) and other bodies have worked very hard to develop secured wireless,” says Martin.

Provided that an installer takes the time to set up the network properly and encrypts the video data, the security of that data should not come into question, he says. Network data is secured through firewalls, encryption and network address translations. The same techniques can be used to secure wireless information.

“The problem we have, is that when we visit sites and look at installations, many of them don’t manage the (network) security very well or manage it at all. If you have the security and you don’t use it, it’s of little value,” explains Martin, adding that the same is true of wired, as well as wireless, networks.

“Obviously it (security) needs to be there up front and then you maintain it over the lifespan of the network.”

The health of the network also depends on how it is being used. If video traffic is being run on a separate network, its security can be micromanaged without concerns about how other systems are affected. But if video traffic shares a network with other applications, like e-mail, then it can be delicate balancing act.

E-mail is an example of “bursty traffic” ”“ data is sent in periodic bursts. Video, on the other hand, is contiguous. “It’s like Niagara Falls, it’s a humungous amount of volume and it’s coming at you 24x7,” says Martin. “Depending on how much volume there is, it can be done well, but the video can also be like an 800 lb gorilla and it can impact your traffic.”

At this point, the lines between IT manager and security manager tend to blur ”“ a situation which can make both camps start to feel uneasy.

“We have a world where we have IT directors teaming up with directors of security and the two have never really worked as a team before. They each their own perspectives and so there’s been some issues that have to be resolved ”“ particularly the nature of video on a network,” says Martin.

But the reality is that physical and IT security are beginning to merge, particularly as wireless begins to become the preferred mode of camera surveillance.

Installations are becoming “more IT heavy than screw driver-, volt meter heavy,” cautions Johnson.

“As the technology advances, you’ll need to have an IT background to install and execute some of the devices,” he says. “If you hook up a wireless or Wi-Fi data bridge that you want to access remotely over the Internet, well now you’ve got to call your IT guy, who needs to open up ports and firewalls and give you IP addresses ”“ all kinds of things that even someone like myself might have trouble with.”


Best of both worlds

Wireless is bound to become more dominant over time, particularly as bandwidth shortcomings are addressed, says Martin. But wired technology isn’t about to disappear. More likely, we’ll see the emergence of more hybrid networks that utilize both, depending on cost parameters and project-specific needs.

“You shouldn’t think of wired and wireless as mutually exclusive,” says Martin. “I’ll use wireless as the last mile and wire an optical fibre as my distribution layer and my core network layer. To me, I look at what’s the right tool for the right job.”


Wireless at work: a case study               
How the City of Stockholm has put wireless cameras to work