Application of CDMA Multi-channel Technology in Video Surveillance
The development of video surveillance systems has roughly gone through three stages. Before the 1990s, closed-circuit television surveillance systems based on analog equipment were called the first-generation analog surveillance systems; in the mid-1990s, PC-based multimedia console systems were called the second-generation semi-digital local video surveillance systems; at the end of the 1990s, fully digital remote video surveillance based on high bandwidth, high-performance computing, massive storage, and intelligent video processing technology was called the third-generation remote network video surveillance system.
As a wireless communication technology, CDMA (Code Division Multiple Access) allows all users to use the entire frequency band (1.2288 MHz) simultaneously, while signals from other users are treated as noise, eliminating the need to consider signal collisions during communication. Due to its special coding scheme, CDMA offers high communication quality and can effectively shield against ambient noise. In terms of security, CDMA has a robust authentication mechanism that can effectively prevent channel eavesdropping. CDMA Multi-channel is the abbreviation of Code Division Multiple Access Multi-channel, a multi-channel bundling technology. Based on the national CDMA communication infrastructure, it bundles 2, 4, or 8 industrial-grade terminal modules through multi-channel (multi-SIM) stacking, integrating network transmission bandwidth resources to provide stable bandwidth for transmitting audio and video signals.
The CDMA mobile video surveillance system designed in this solution utilizes CDMA technology for wireless network transmission of video data, adopting the advanced video compression algorithm H.264 and a streaming media video data compression technology wireless transmission network solution, integrating CDMA data communication functions and digital video encoding functions. The system compresses camera images and transmits them to the CDMA network through intelligent wireless communication terminals, enabling video data interaction, transmission/reception, encryption/decryption, encoding/decoding, and link control and maintenance functions. Depending on the application, real-time dynamic images are transmitted to the nearest China Unicom communication network to the user. Real-time image information can be obtained from the system central control terminal via the Internet. This system integrates the advantages of the CDMA network and the Internet, achieving a breakthrough expansion in space and distance. The front-end video surveillance points designed in the system (which can integrate GPS functionality) are suitable for vehicles and individual police officers. Vehicle-mounted video equipment is installed on the roof or behind the windshield of each patrol vehicle, with the power supply directly connected to the vehicle battery or powered through a vehicle inverter; the personal system can use a portable terminal integrated with digital DV capture for one-way transmission to the patrol vehicle.