Provide a reliable and flexible CCTV network capable of delivering high FPS and telemetry control to two control centres simultaneously.
Utilised Wavesight’s high performance OFDM wireless bridges to deliver the performance, output and flexibility to achieve the business requirements.
Leading Dutch system integrator QCAT were asked to design a wireless network to support surveillance cameras surrounding Amsterdam Central Railway Station.
The requirement was to deliver analogue camera pictures to the Central Supervision Unit of the Dutch Railway (CTR) and digital camera pictures to the Police Station at the Nieuwerzijds Voorburgwal (NZVW), over half a kilometre away from Central Station. To be able to deliver a robust solution, Q-CAT chose Wavesight to provide the wireless infrastructure and Indigo Vision to provide analogue CCTV encoding to IP. Q-CAT already had a lot of experience as a system integrator of wireless video transmission for both companies.
Choosing a Wireless Solution
The system chosen was based on radio communication with high performance Wavesight OFDM radio bridges, which in this case had two key benefits. First, they offered near line of sight (NLOS) capability, which meant that even where clear line of sight (CLOS) was not available, a link could be established and sufficient bandwidth would be made available despite obstructions. This provided greater flexibility and reduced the number of radios required (and the time it took to install them) over alternative solutions. The second benefit was the range of frequencies available, one of the widest on the market from a single product. In this case it was essential to use frequencies outside the public domain. WaveMAX units operating at 5GHz provide a sufficient number of non-overlapping channels to avoid interference with neighbouring channels in a medium-large WLAN environment.
Designed for future growth
Q-Cat’s solution for the Central Station surveillance area used 20 strategically placed cameras, divided into 5 sectors, using 90° or 120° sector antennas. By doing this only 5 free frequencies were required, providing scaleability for future growth.
For further flexibility, the bandwidth control utilised IndigoVision’s VideoBridge-8000 Codec to deliver 2.5Mbps per video stream in MPEG4 2CIF quality at 25 frames per second. In this configuration, an upgrade to an increased number of cameras was included in the design to meet future expansion needs.
Real time feeds to both locations
The feeds initially went back to the CTR for onwards transmission to the police station. However, the police authority changed their requirements, because the resulting delay in video transmission was unacceptable. To ensure a reliable, simultaneous connection for the NZVW police station, Q-CAT again used WaveMAX wireless ethernet bridges between the two sites. The result was that all dome camera-pictures were available to the police station at the same time with 25 fps. Apart from providing real-time images, WaveMAX’s high throughput allowed remote control of the cameras from the police station as required.
This approach provided the ability to monitor the Central Station Area with the minimum of manpower, 24/7, with the added benefit of easy expansion or redeployment as required. For Q-CAT this has been a very successful project and a clear demonstration of their ability to integrate wireless technology to provide the reliability, performance and flexibility their client needed. As Piet van Vliet, managing director of Q-cat stated “Fully meeting the requirements and the deadline was critical; Q-CAT needed dedicated partners who could work with us to achieve this goal. Working closely with Wavesight and Chubb Lips security, the project was completed on time and to the client’s satisfaction”.
WaveMAX – suitability for CCTV transmission
WaveMAX operates in the license exempt 2.4 and 5GHz frequency bands. Its use of Orthogonal Frequency Division Multiplexing (OFDM) modulation provides significantly improved performance in both near line of sight (NLOS) and in some cases no line of site environments over distance, allowing voice, video and data delivery of up to 108Mbps, ideal for high resolution, high FPS CCTV use.
Ruggedised to exceed IP65, and featuring tough vandal resistant housings, the Wavesight product range provides the all weather capability, reliability and low maintenance critical for CCTV and data transmission.