Customer Requirements

September 1st 2005 was the 40th anniversary of the founding of the Tibet autonomous region. The local government then decided to install a video surveillance system in the downtown areas to ensure public security during that anniversary celebration, maintain future social stability and enhance the case solving rate of the local authorities and establish a more positive social environment.

According to the project, 20 surveillance points will be installed at the main crossroads, governmental institutions and downtown areas. As Lasa is in the plateau where optic fiber costs too much and requires difficult construction, wireless data transmission is the most effective and cost efficient solution. The customer requires high resolution, therefore higher data payloads, on the surveillance system to show not only the general condition of the streets but also the vehicle license plate must be be able to be clearly identifiable.

Project Aim

The downtown area and key streets will be monitored in this project, and our wireless products will establish wireless connectivity for all the 20 surveillance points. The project requires high definition video, with the ability to view recorded video at will, to ensure public safety and enable to the local officials to ascertain offenders identities.

Solution

In this project, the all-weather wireless outdoor bridges are used, providing stable and high bandwidth for the video transmission and ensuring high transmission quality. The operator is able to monitor the streets, via the surveillance images, and dispatch police forces in a timely manner. This allows for a more dynamic and event driven response to various conditions that arise, increasing response time and efficiency.

Since the 20 surveillance points are scattered at various points throughout city, five wireless outdoor bridges were installed at the center point, each one with two 15° external panel antennas, connected via a power divider, covering a 150° area and enabling thorough coverage. However, due to the complicated geographic environment, three surveillance points can not communicate with the center directly, so two repeaters are then used.

Network Structure

The analog signal from the video camera in each surveillance point will first be encoded into a TCP/IP compliant digital signal via a video server, and then be delivered to the surveillance center via a wireless client. The digital signal will then be decoded to the appropriate video signal with a decoder, allowing a clear and real-time video picture from all 20 surveillance points to be watched simultaneously at one location.

Conclusion

This project has been completed successfully; the clear and real-time system has been received with a favorable reception. What's more, the local operators are quite impressed by the convenient installation and easy configuration of the units.
Not only has their requirment been met, but the network setup and hardware is set up for link redundancy and future extensibility, avoiding future expense.