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.