Wireless transmission of security video has business
advantages. The capability can come from wireless cameras and encoders. There
also are different types of wireless transmission. Photos courtesy of Verint
Systems
Doing things differently are, well, different for many businesses. Doing things differently can add complexity but sometimes the return on investment is worth the extra effort.
Adding the power of wireless transmission to IP video networks can create a robust, flexible solution. By connecting networked cameras using wireless technologies, security organizations can transmit high-resolution video across wide expanses to a central monitoring location in real-time. Wireless can overcome challenges such as distance, lack of network infrastructure and inclement conditions to enhance security.
However, before implementing wireless technology as part of a networked video system, there are several key factors that must be considered, including how to choose an “enterprise-class” wireless solution, wireless network security, whether to transmit over licensed or unlicensed wireless spectrums, and the best type of antenna to use in order to achieve the best results.
SECURITY, FREQUENCY, TRANSMISSION
The first concern that many enterprise security professionals and their CEOs raise about wireless transmission technology relates to security. Since the network over which wireless video signals travel is literally “thin air,” it cannot be physically secured like a traditional coaxial or Ethernet cable. This gives many people the false impression that wireless technologies are highly vulnerable to attack. In actuality, with proper authentication and encryption technology, wireless transmission is equally, if not more secure, than wired networking mediums. Without a physical cable to splice into, the signal is much more difficult to intercept.However, it is important to choose a wireless product that employs standard encryption and authentication protocols to ensure the highest level of security. Most enterprise-class wireless solutions incorporate these standards.
Enterprise-class wireless solutions differ significantly from commercial off-the- shelf products typically used in home or small office computer networks. Enterprise-class wireless solutions, de-signed for use in video surveillance networks, are often ruggedized for operation in the extreme conditions present in outdoor use, including extreme heat, cold, rain, wind and other environmental factors. In addition to their tough physical design, they incorporate industry standard encryption and authentication technologies that far exceed the robustness of those found in off-shelf products.
Wireless video signals travel over radio waves, or frequencies, to transmit data between devices without cables or cords. Higher powered signals are able to travel further distances and around greater obstacles than lower powered signals. High-powered transmissions usually require government licenses to broadcast while low-powered transmissions are often unregulated. Licensed frequencies are regulated by the Federal Communications Commission, responsible for assigning frequencies for exclusive use by an organization in a specified geographic range. This ensures that specific frequencies remain open and exclusive for use by police, fire or private enterprise.
In contrast, unlicensed frequencies are open for use by anyone which can sometimes lead to signal cross-over. When deciding whether to use licensed or unlicensed frequencies, security and IT and telecommunications colleagues must carefully consider factors including the number of other wireless networks in close proximity and the distance over which the wireless video signals will need to travel.
Another important factor that determines the effective transmission of wireless video signals is antennae. There are two main types of antennae to consider; directional and omni-directional. Each type of antenna has inherent advantages and disadvantages which will help determine which is best suited for a specific application. A directional antenna is limited to transmitting a concentrated, powerful wireless signal in one direction. This allows wireless signals to travel long distances in one direction but limits the wireless signals ability to blanket a perimeter. In contrast, an omni-directional antenna transmits signals in all directions in order to provide ubiquitous connectivity over a short range but it lacks the power to transmit over long distances.
UNDERSTANDING THE TECHNOLOGY
Beyond the basic factors, there are four key types of wireless technology: WiFi, 802.11n, WiMax and Mesh networking.WiFi is perhaps the most commonly recognized and widely deployed wireless technology thanks to its adoption for computer networking in homes, small offices, airports and local cafes. Also referred to as 802.11, the majority of WiFi technologies operate on unlicensed frequencies and are well suited for wireless video surveillance applications. WiFi signals typically have a range of 150 ft. for indoor applications and 300 ft. in outdoor environments with data speeds, also called bandwidth, of up to 24 megabytes per second (mbps). At this data transfer rate, it is possible to have multiple intelligent edge devices, including IP cameras and wireless video encoders, streaming video from access points on the network edge to a centralized monitoring station.
802.11n is next-generation WiFi that is still in the development phase, with an expected release in 2008. It will operate on the same unlicensed frequencies as traditional WiFi technology but will offer data transfer rates at almost ten times that of current technologies. This is accomplished by using multiple antennae to create multiple wireless paths over which data can travel. This higher bandwidth will allow more devices to share the same network and will allow for uninterrupted streaming of ultra-high resolution images.
WiMax, or 802.16, is another variation on WiFi to provide long-range wireless connectivity. WiMax networks offer connectivity at 45 mbps over a range of between 4-10 miles which makes them an ideal choice for municipal security applications.
However, current commercially available WiMax solutions operate exclusively on licensed frequencies which can contribute to higher operational costs. The significantly extended range and higher bandwidth of WiMax is well-suited for surveillance networking over perimeters that span several square miles such as ports, energy pipelines, transit lines and reservoirs. However, WiMax capabilities may be overkill for most wireless video security network applications.
Another form of wireless technology is wireless mesh networking. As the name indicates, mesh networks use a series of interwoven wireless signals to extend the reach of WiFi transmissions by creating a long range backbone over which video data travels. Mesh networks are ideal for providing low bandwidth access to a large coverage area. However, because of the bandwidth constraints of mesh networks, the technology is not ideally suited for bandwidth intensive and can delay constrained applications such as video surveillance.
