October 20, 2010

Submitted by IndigoVision. Dr Oliver Vellacott, IndigoVision CEO, discusses the benefits, applications and technology involved when IP video surveillance is deployed using wireless networks.

One of the many benefits of IP video surveillance technology compared with traditional analogue video equipment is that digital video is compressed and streamed across standard ethernet networks using the internet protocol (IP). This is exactly the same protocol as used on corporate networks and the internet. Digital video can therefore be transmitted across any broadband network connection, i.e. cable, fiber or wireless.

There are a number of wireless technologies that allow digital
surveillance video to be easily transmitted across large urban areas and
from remote locations. As far as the IP video system is concerned, the
wireless interface is transparent and is simply a replacement or
extension of the standard wired IP network. Connecting to a wireless
network is the same as connecting to an ethernet switch.

Benefits of wireless IP video
Combining IP video surveillance with wireless networks can provide the user with a number of significant benefits:

Wireless technologies
Wireless broadband networks
Wireless broadband typically operates in the unlicensed frequency
spectrum and provides high-speed wireless internet and data network
access over a wide area. For IP video applications, wireless broadband
networks can be deployed in a number of configurations:

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Different network technologies, both wired and wireless, are often
deployed together to achieve very wide area coverage. Chihuahua State in
Northern Mexico has deployed such a system based on distributed IP
video technology. Covering nearly 100,000 square miles, Chihuahua is the
largest of Mexico’s states. Its capital and largest city has the same
name, Chihuahua, and it includes eight other major cities. The truly
distributed nature of the system allows an operator in the state capital
to view video from any other city in the region from a PTZ camera he
can control. The surveillance systems in each city are deployed using
point-to-multipoint wireless networks. Each city is connected to the
state capital via fixed network links.

WiMAX
WiMAX (Worldwide Interoperability for Microwave Access) is a telecom
technology that supports wireless broadband access over large distances
(many miles) as an alternative to cable and DSL. It is different from
Wi-Fi, which is a shorter range system (coverage over hundreds of feet).

An excellent example of this technology is in place at the Acuicola
Marina fish farm in the Spanish Province of Castellon on the
Mediterranean coast. Their offices and a warehouse are located at
Burriana, two miles inland, with the fish farm facilities sited six
miles offshore. The valuable fish stock is a target for poachers and
Acuicola Marina has always found it difficult to police the offshore
facilities. To overcome this, they deployed an IP video system with a
wireless network infrastructure consisting of a local Wi-Fi network
covering the offshore facilities with a 7 Mbps WiMAX radio link back to
the onshore offices eight miles away. As well as providing security for
the fish stock, it also offers operational benefits, with submersible
cameras monitoring fish stocks and food distribution.

Mobile wireless broadband
This provides high-speed internet access through existing 3G mobile
phone networks. It is an established technology that many of us use on
our phones to access the internet while on the go. It can be a very
powerful tool for law enforcement officers to monitor live and recorded
footage from surveillance cameras on a laptop mounted in police
vehicles.

This can be demonstrated by the fully integrated public video
surveillance system that has been developed in the City of Lansing,
Mich. Here, video is streamed at 30fps across various network
technologies, including ShDSLs, fiber, mesh wireless and mobile 3G
broadband. The police department’s 60 vehicles each have a laptop with
high-speed broadband 3G technology that allows officers to view and
control any camera in the system.

Commenting on the use of mobile surveillance equipment, Lansing police
chief, Mark Alley, said, “As we are always looking for ways to free up
patrol time for our officers, we decided that we were going to take an
aggressive approach and get the equipment out there to our officers so
they can be more effective and efficient.”

Satellite
Satellite broadband access is an expensive communications solution, but
is often the only technology available for remote areas. Since the data
has got to travel about 20,000 miles to reach its destination, latency
(or delay) can be more of an issue than with standard radio-based
wireless networks. It can also be affected by weather and climatic
conditions.

An innovative wireless surveillance system is helping to cut crime and
provide a safe and secure environment for visitors to the Grand Canyon
West Resort, Az. A distributed IP video system has been deployed at
multiple sites, providing an integrated surveillance solution across a
wide area. Grand Canyon West is a popular tourist destination on the
west side of the canyon owned and operated by the Hualapai tribe. The
resort includes Skywalk, which allows visitors to “Walk the Sky” on a
horseshoe-shaped glass bridge that overhangs the Grand Canyon.

Several sites, including Eagle Point (home of the Skywalk), Guano Point,
a hotel, fuel depot and airport are all centrally monitored from the
airport terminal building. The facilities are located several miles
apart and are completely standalone with no cabling or infrastructure
between them. All the sites are powered by their own generators. Each
local IP network is interconnected using a satellite broadband network.

Bandwidth
Wireless networks typically have far lower bandwidth than wired
networks. A wired network can have an available bandwidth of up to 700
Mb/s, whereas wireless networks typically offer no more than 25 Mb/s. It
is therefore paramount to minimize the amount of data transmitted
across the wireless portion of the network. This can be achieved by
ensuring that the IP video system deployed has the best compression
available, is based on a distributed architecture and has features that
ensure the minimum amount of video is transmitted at all times.

Compression
Deploying the very best H.264-based video compression technology can
make a significant difference to the performance of the wireless IP
video system. This is particularly important when using increasingly
popular high-definition (HD) cameras with their higher resolutions and
bit-rates. The data rates from different manufacturers’ cameras can vary
significantly, even when comparing cameras implementing H.264. An
average IP camera can transmit five or six times more data than the
best-available camera for the same scene. With the limited bandwidths
available from wireless networks, this is an important consideration.

Architecture
There are typically two different architectures used by IP video
systems: centralized and distributed. A centralized architecture uses a
master database—usually located in the central control room or head
office. A distributed architecture spreads the data around the security
management system, generally keeping it close to where it is produced or
needed. Normally, much more data is transferred across the network to
the centralized video and storage servers than would be the case with a
distributed system, where video workstations and network video recorders
(NVRs) can be located at the edge of the network. Well-designed
distributed systems reduce the need for large amounts of data to travel
large distances, i.e. between the central network and the edge
components.

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Multicasting
IP Multicasting is an extremely powerful networking feature that allows
video from the same camera to be efficiently viewed and recorded by
multiple operators at the same time, with the same network bandwidth
requirement as would be for a single operator. Using multicasting on a
distributed system is an extremely efficient solution for IP video
systems.

Analytics
Real-time analytics running in the cameras at the network edge can be
used to reduce the amount of video that is streamed across the wireless
network. When a scene is inactive, there is no point in transmitting
full-frame video. Motion detection analytics can be used to detect a
change in motion in a scene and automatically modify the video output
stream from low frame-rate to maximum.

Dual streaming
Cameras on some IP video systems are capable of dual streaming; that is,
outputting two separate video streams at different frame-rates.
Typically, this could be used to transmit a lower frame-rate stream
across a wireless network, while using a full frame-rate stream for
recording on a local NVR.

Bandwidth management
Leading IP video systems have a set of tools for bandwidth management.
These allocate bandwidth to each camera stream based on a pre-configured
maximum available for a particular network setup. These tools would
typically work on a WAN connection, not on the local network. In the
case where the WAN connection is wireless, this can be a very useful
tool for ensuring the available bandwidth is not exceeded and works well
alongside features such as dual streaming, mentioned above.

Summary
The benefits of using wireless networks with IP video systems are clear
and can sometimes be the only solution available for large or remote
areas. However, the overall performance of the network (and, hence, the
surveillance system), is very dependent on the performance, features and
capability of the IP video system itself. Choosing the correct IP video
technology that has good compression, the most suitable architecture
and fully-featured IP cameras is very important.

Oliver Vellacott founded IndigoVision in 1994. He was previously a
product manager with a background in intelligent camera products. Oliver
studied piano at the Guildhall School of Music before gaining his first
degree in Software Engineering from Imperial College London, then a
Ph.D. in Electrical Engineering from Edinburgh University. CLICK HERE
for IndigoVision.