Coming of Age
Wireless mesh enables fixed, portable and mobile video applications
- By Ksenia Coffman
- Jun 01, 2011
Wireless transmission for security is often used in outdoor
settings where there is not existing wired infrastructure,
or where it’s cost-prohibitive or impractical to implement
wired solutions. Wireless networks also are ideal for temporary
installations such as special events, fairs or rallies,
as well as longer-term installations, such as construction sites. Installing wireless
is much faster and does not require major construction projects or disruptions
that fiber installation causes. We’ve seen wireless deployed for indoor surveillance
where it’s impossible to wire, as is often the case at historic properties.
The growing use of megapixel and HD network cameras and the rising demand
for mobility in video surveillance places new demands on wireless network infrastructure
called upon to support the new applications. Video surveillance requires
an extensive amount of bandwidth, especially for these new cameras. Without
enough bandwidth, cameras cannot deliver evidence-grade video or support video
analytics. The video security system is only as good as the network that enables the
transmission from the cameras to the command center. That is why transmission
can become the “Achilles’ heel” of the project if cameras need to be deployed in
the areas where no networking infrastructure exists.
Today’s MIMO-based wireless mesh networks have already been deployed to
support HD and megapixel video surveillance. Its limitations compared with fiber
continue to be throughput -- wireless mesh is not yet capable of providing gigabit
speeds. However, with a cost reduction of up to 90 percent compared with deploying
fiber, this tradeoff is often acceptable to customers.
Fixed Video
City surveillance cameras have long been a staple in major municipalities within
the United States. Cities deploy them to reduce nuisance crimes, improve security
and prevent vandalism on city-owned properties, clear out “drug corners,” and, in
general, improve the perception of public safety among residents. Cameras also
are deployed in downtown areas and around public buildings for traffic and crowd
management, as well as for emergency preparedness. Hence, city surveillance projects
are often funded through Department of Homeland Security grants.
The best practice for video security network design is multi-mesh, interconnected
by wired or wireless backhaul. Fiber often plays a role as a backhaul when
it is available and accessible. To illustrate the point on how these networks are built
out, here are a few examples:
The Dallas Police Department uses a multi-mesh design with point-to-point
wireless backhaul that deploys mesh for street-level connectivity and BridgeWave
wireless links for backhaul. The Dallas PD wanted a network independent from
any other city infrastructure, so it opted for a 100-percent wireless solution.
The Chicago Office of Emergency Management and Communication did a video
install deploying a multi-mesh design with fiber backhaul. The city already had a lot of fiber installed, so wireless mesh fills in the fiber gaps.
The Los Angeles County Sheriff’s Department is expanding its wireless video
security network using Firetide MIMO mesh nodes in point-to-point configuration
(dual-radio bonded) as an alternative to dedicated point-to-point backhaul.
Los Angeles lacks the extensive fiber infrastructure of Chicago, hence the decision
to use 100-percent wireless connections.
Portable Surveillance
To monitor special events, remote areas and troubled neighborhoods, the municipality
of Carolina, the industrial capital of Puerto Rico, implemented a mobile
command center with wireless video surveillance. Since last December, the mobile
unit has assisted police in apprehending drug dealers and confiscating illegal weapons
in remote mountain areas; prevented car thefts and burglaries in several commercial
and local shopping centers; and monitored crowds at special events such as
music festivals, park inaugurations and a busy Christmas theme park.
“The citizens love the services that the mobile command center provides. Almost
every day, we get requests to bring the command center to their neighborhoods.
Our people know that wherever we have used it, criminal activity has decreased
and people feel more secure,” said Lt. Jose Matta, director of the virtual
security department in Carolina. “Where the mobile command center has been deployed,
there has been a 15 to 17 percent reduction in crime in those areas and an
overall decline of 20 percent in the municipality since we began using the vehicle.”
The mobile command center was funded by the Autonomous Municipal Government
of Carolina, which has been expanding its fixed-video surveillance system
for the past five years with a combination of fiber optics-based and Firetide wireless
fixed-video surveillance of parks and downtown areas.
The mobile unit is equipped with a Firetide mesh node with two Sony PTZ
cameras on a mast extending more than 30 feet in the air. Four additional Sony cameras and Firetide nodes can be deployed
around the vehicle to create a
mesh to cover larger areas for surveillance.
The video feeds, managed by
software from American Dynamics’
Intellex, are streamed at 30 frames per
second and monitored in the command
center by civilians who are trained to
alert the police, fire department or
emergency medical service, depending
upon the situation. The video is saved
for 15 days but can be transferred to
CDs if needed for evidence.
Wirelss Offload
Infrastructure mesh also is being deployed
for wireless offload of recorded
mobile video. The town of Los Gatos,
Calif., has deployed such a solution for
the Los Gatos-Monte Sereno Police
Department.
“Prior to deploying wireless offload,
police officers had to run over 100 feet
of cable to their vehicles to download
the video,” said Chris Gjerde, information
systems manager for the town of
Los Gatos. “As you can imagine, they
did not enjoy that part of their daily
routine. We also noticed that outdoor
connectors often had to be replaced,
each failure creating a call for service
to our outdoor networking contractor.
Wireless mesh saves us both time and
money, and the high-tech approach is
a hit with our patrol staff. Based on
the initial success, we are expanding
the system to outfit all of our videoequipped
cars with wireless mesh.”
Infrastructure Mobility
Mobile video surveillance to and from
moving vehicles is increasingly popular
with law enforcement, first responders
and transportation agencies interested
in augmenting their fixed security systems.
Firetide infrastructure mobility
solutions have been deployed in subways,
trains, and buses for surveillance
and public services. Examples include
Amtrak in New York City, Seoul Subway
and Mumbai Metro projects.
With Firetide’s mobility controller
functionality, devices such as IP video
cameras, Wi-Fi access points and RFID
readers maintain network connectivity
while traveling at high speeds. The mobility
infrastructure provides the bandwidth
and intelligence needed to manage
connectivity between the mobile and
fixed nodes, ensuring fast and efficient
handoff and delivering seamless video
surveillance and other services.
HDTV and Megapixel Network Cameras
Public safety officials want the high definition
cameras for projects where more
detail and coverage is required, such as
for forensic and criminal investigations,
and for the reliable identification of
people, license plates and other objects.
In Melbourne, Australia, the Moreton
Bay Regional Council deployed the
most extensive wireless IP video surveillance
network in the country, with 130
square kilometers of mesh coverage.
Most importantly, the system needed
to meet the requirement to transmit
high-resolution and HDTV live video
feeds. The extended coverage area and
stringent performance specifications
were the major factors in selecting wireless
products for this project. Forty-two
Firetide outdoor mesh nodes form the
infrastructure backbone of the project,
supporting close to 50 outdoor IP video
surveillance cameras.
Selecting the Right Technology
All wireless technologies are not the
same, and due diligence should be part
of any technology-selection process.
Wireless technology used in the system
is essential to its success -- choppy or
granular video caused by the network is
a critical flaw when it comes to surveillance.
Things to look for:
Video performance. Video applications
can eat bandwidth quickly, and
any wireless infrastructure should have
plenty of room to grow, even if current
requirements appear limited.
Security and privacy of video streams.
The most secure systems offer end-to-end
encryption supporting WPA2 and
WEP. In addition to encryption, encapsulation
schemes can also be used
to add a layer of security, because only
the mesh nodes can see the encapsulated
packets.
Multi-service networks. Today’s security
networks have moved beyond
sensor alarms and must support latency-
and jitter-intolerant applications
such as video (surveillance) and voice
(mass notification). The transmission
medium must give appropriate priority
and quality of service to mission-critical
applications.
Ease of setup. Security systems require
a great deal of flexibility, and wireless
networks offer advantages there
that wired systems just can’t match.
Cameras can be installed in buses or
trains, fixed on buildings, repositioned,
added or replaced, and there’s no need
to pull cable, drill holes or disrupt dayto-
day operations. In addition, unlike
with a point-to-multipoint system, any
mesh node can act as a head end, allowing
multiple command centers to be set
up, at any point on the network.
Multicasting. Multicasting enables
video feeds to be sent to multiple destinations
for simultaneous viewing and
recording, from police headquarters,
field command centers and joint operations
centers established for special
events. Multicasting is essential for
monitoring by multiple decision-makers,
but it can severely burden a wireless
network. Encapsulation techniques, in
addition to increasing security, enable
multicasting of video streams across
wireless networks while affecting bandwidth
minimally.
Will LTE Replace Mesh?
No, at least not in the foreseeable future.
The two technologies supplement
each other. For example, organizations
build out mesh backhaul to connect
the cameras -- in lieu of fiber -- and
then use a cellular broadband technology
to provide access to the feeds from
the field via cellular routers. To illustrate
the point, wireless mesh provides
100 to 150 MBps of user throughput
per hop -- essentially equaling wired
Ethernet and approaching fiber. Cellular
broadband provides an average of
5 MBps download, 1 or 2 MBps upload,
with much higher latency. It’s
also a point of ownership: do you want
to own the infrastructure, or would
you rather lease the capacity from the
cellular carrier?
This article originally appeared in the June 2011 issue of Security Today.