The author makes an analysis on the transmission of wireless video for surveillance, in order to illustrate in a simple way the different methods and schemes that exist to link them. By: Carlos Quintanilla*
When in a project we encounter situations that require wireless video security links, for many of us this is an application that we prefer to avoid and many times we end up complicating our work trying to produce alternative solutions.
We have the impression that to carry out this type of projects it is necessary to have a work staff with characteristics different from those normally found in our human resources portfolio, however, this may be just a prejudice with which we have grown and created the video security industry.
If we look back a few years, this branch of security was born practically together with the explosion of the Internet, with video recorders capable of being on the network and with pioneering companies that wanted to manage their surveillance resources under one roof, and then make a great leap to the birth of IP cameras and their certain advantages. For all this, end users should preferably have their own networks because otherwise, it was difficult to be considered as an option due to its high implementation costs.
This development and growth of technology took its first steps with links such as local networks, using resources that were initially intended for data transmission but temporarily adapted for video transmission, resulting in solutions strictly limited to the resources provided by the end user.
Today
Nowadays we constantly hear many success stories in wireless video transmission and this often makes us want to venture more into the subject. When we talk about wireless links we must bear in mind that video transmission is one of the most critical situations of driving effectively, and this leads us to take into consideration some points necessary to analyze:
- Total number of cameras and location
- Location of monitoring room with respect to cameras
- Define "camera-camera" and "camera-monitoring center" view lines
- Desired video resolution
- Bandwidth to use
- Distances between all devices involved (camera-camera and camera-monitoring center)
- Terrain elevations (if possible)
To develop these bullet points we have the advantage that there are several tools at our disposal and that have no commercial cost, such as Google Earth, Google Maps and the different calculators offered by both camera manufacturers and manufacturers of wireless transmission systems.
Following these first seven questions we should not have problems when making a basic configuration of a wireless system, or asking for support more effectively from companies specialized in the field, if it is the case.
Security and encryption
Compared to some regular systems, many of the manufacturers specializing in wireless transmission systems have designs with greater reliability and lower latency in the use of PTZ and VoIP video systems. Currently the market offers us several levels of security that serve as a sales tool and give them peace of mind to demands of all types in the different sectors of the market. Listed below are some of these levels:
- Undetectable transmission protocols for common Wi-Fi networks
- Secure routing thanks to codes or passphrase
- Encryptions in programmable bits (HTTP, AES, 3DES, RSA, SSL)
- Fully compatible with Virtual Private Networks (VPN) Flat Traffic
Types of links and devices
The most common and used links can be summarized in – Point to Point, Point to Multipoint and Mesh or Mesh Type links.
It is important to clarify that when we design a project we should not necessarily consider one antenna for each camera installed, but try to centralize the largest number of nearby cameras and send them by a single link with the bandwidth necessary to transmit the set. To calculate the bandwidth we must consider how many CIFs we want to transmit and the total distance that the link will have. This will save us costs, eliminating links that may not be necessary.
As for the antennas normally used there are the following:
- Omni-directional: They have a gain of 5-12 dBi with an effective range below 600m/2000ft.
- Directional panel: With a gain of 12-23 dBi and an effective range of 10km/6 miles
- Directional or parabolic grid antenna: This has a higher gain of 18-32 dBi and an effective range of up to 50km/42 miles.
Advantages
Among all its advantages we must emphasize the following:
- Flexibility: Several types of links for different types of applications capable of transmitting countless packet options.
- Scalability: Ability to grow on its own basis by responding to situations by routing packets around obstacles and interference along alternate paths within its network.
- Security: Fully programmable to the desired levels
- Easy Installation: Significantly lowering our man-hour costs maximizing our resources and giving a new profile to our delivery times
Applications
It is possible that each of us has encountered an infinity of applications for this tool. Among them we can mention the following:
- Airports
- Urban or municipal surveillance
- Colleges and universities
- Government Sector
- Military Sector
- Seaports
- Rural area
* Carlos Quintanilla is the regional project manager for the Central American region of Full Protection.
