By C. Sailaja
Closed Circuit Television (CCTV) is a closed & connected system used for surveillance generally in public places like commercial complexes and office buildings. CCTV is mainly used for security and monitoring purposes.
Wireless technology has transformed our lives in many ways from mobile phones to Wifi connectivity. One area where IoT is making an impact is CCTV surveillance & monitoring.
Digital wireless camera uses the IEEE 802.11xcommunication standard, also known as Wifi. The standard has various encryption methods. This helps in data security during transmission. The data is encrypted during transmission and the receiver decrypts the data with a security key. Any receiver without a matching security key will be unable to decrypt the signal and view the image.
The benefit of using 802.11 wireless standard is that they all operate in a license free spectrum. It provides increased performance and much longer distances in combination with very high security.
There are two speeds in which the IEEE 802.11x operates, 2.4 GHz & 5 GHz. Frequency of the electromagnetic waves governs the bandwidth and the distance of coverage. For higher frequency of the wireless signal the range is shorter. For e.g. 2.4 GHz signal covers a larger range than 5 GHz. 2.4 GHz frequency wireless network is used by many devices such as cordless phones, mobiles & microwaves and hence can cause interference. Due to the traffic and interference, network speed reduces. Hence 5 GHz s preferred to 2.4 GHz though it is costly.
The advantages of Wireless communication are:-
- Significant reduction in Installation work.
- Reduces space & power requirements
- Easy to expand to accommodate changes and additions
- Excellent for monitoring applications
- Suitable for remote or inaccessible locations
- No need to modify existing wired infrastructure
Wireless CCTV system comprises of IP based cameras along with Access point / Radio.
The Components in a Wireless CCTV system comprise of the following:-
- IP based CCTV Camera’s – Pan Tilt Zoom (PTZ) & Bullet type
- Power Over Ethernet (POE) Switch ( Edge Switch)
- Access Point (Radio)
- Base Station (Gateway)
- Ethernet Switch ( Core Switch)
- Video Management System (VMS)
- Network Attached Storage (NAS) – Storage
- Video Monitors
- Operator Work Station
The IP based Cameras are installed along the perimeter of the plant and in the plant arterial roads to monitor the logistics of the plant operations. The criteria that are required to be considered are:
- The availability of the Line Of Sight (LOS) for the radio signal transmission and
- Interference of other radio frequencies in the vicinity of the plant
Based on the availability of clear LOS, point to point and / or point to multipoint configuration for radio communications considered. A site survey along with the vendor to finalize the system configuration is required before proceeding with the detail engineering.
The Access Point & the POE edge switch are housed in a Junction box along with the camera on a pole along the periphery of the plant. The CCTV’s are to be placed strategically based on the distances covered. A combination of PTZ along with the Bullet type of CCTV’s ensures continuous coverage of the Perimeter without any blind spot in surveillance monitoring. In case of non-availability of Line Of Sight (LOS), repeaters are to be used for transmission of signal to the Base Station.
All cameras are connected on wireless network license free band (2.4 GHz / 5 GHz).Power supply is provided at the base of outdoor pole from which connectivity is established for cameras and wireless devices. A typical wireless CCTV configuration indicating various components is shown in Figure 1.
Server for CCTV System is located in the Central monitoring room. The Wireless Base station is located at the top of central monitoring building and Ethernet/network core switch connecting the base station to the servers & monitors is housed in the Network cabinet.
The Central Monitoring room will house the Core Switch, Video Management System (VMS), Network Attached Storage (NAS), 42″ Video Monitors and Operator Work Station.
Tata Consulting Engineers Ltd (TCE) can offer full-fledged engineering services related to wireless CCTV systems for surveillance monitoring. The services include feasibility studies, basic and detailed design and engineering of complete Wireless CCTV system. The services would also include procurement assistance, Vendor drawing/document reviews, factory/site inspection and construction and commissioning supervision.