CDMA-based network video surveillance System Solutions

Transcription

1 1 Contact:Peter Zhang CDMA-based network video surveillance System Solutions Introduction In recent years, mobile communication, video surveillance for its intuitive, easy to use, rich content and are widely used in many important occasions, it has become the primary means of security surveillance. With the rapid development of communication technology and computer network technology, wireless network technology has become a computer network in a vital part, but also the rapid expansion of its applications. Due to the remote video monitoring system to achieve the goal of remote monitoring, remote control and other functions, providing new tools for unattended applications. CDMA technology enables cost appears reasonable, relatively low technical threshold of wireless data transmission technology site in the monitoring system to the real-time data transmission remote monitoring center possible. CDMA is (Code Division Multiple Access) Code Division Multiple Access technology, is an advanced wireless spread spectrum communication technology in recent years, for digital cellular mobile communications. CDMA allows users to send and receive data at end packet transfer mode, without the need to use circuit-switched mode network resources. Thus providing an efficient, low-cost wireless packet data services. Advantages CDMA data transmission comprising: (1) high transmission rate, the maximum theoretical bandwidth of up to 230.4kb / s; MSCBSC Mobile Communication Forum, (2) always-on, real-time transmission of data; (3) by traffic charges, and reasonable price; (4) IP-based access to the entire Internet. Remote video monitoring system CDMA network using wireless propagation medium, got rid of cable bound within a certain range can transform any location. Without active area restrictions, through CDMA communications network, can easily achieve remote mobile monitoring. Two systems networking solutions After the country terminal image data collected, data should be sent to the monitoring center, and some wireless data transmission function of the terminal by the CDMA RUTER to complete. En overall CDMA RUTER with the monitoring center on two programs: CDMA + Internet connection; CDMA network connection. Its system topology shown in Figure 1 and Figure 2. (A) the system topology 1 The monitoring center Internet access, and access methods are a variety of ways, as long as the public IP address (dynamic or static) can be. Telecom, China Netcom and other telecommunications companies to provide dedicated access IP typically receive a fixed public IP address, which is accessible on the Internet IP address, connection RUTER with the monitoring center server via CDMA + Internet, security levels lower, but may by connecting the carriers via VPN tunnel to the monitoring

2 2 Contact:Peter Zhang center server, which can greatly increase the security level and can reduce the delay. Figure 1 - system topology 1: CDMA + Internet connection B) mobile communication system topology forum for leading communications technology forum, we specialize in mobile communications technology, communications engineers online home.._2i; R + R5_ The mobile communication forum for leading communications technology forum, we focused on mobile communication technology, communications engineers online home..c%] 3G.]% C'l CDMA network connection can be dedicated access or CDMA terminal connections. Line access via data lines connected by mobile operators PDSN (CDMA router) to the monitoring center, the monitoring center to obtain a fixed IP address within the network. RUTER network IP address obtained in the same network segment, its data security is good; a small delay; high cost. CDMA terminal connections require mobile operators assigned to the monitoring center CDMA network fixed IP address; open-end CDMA user data communication. RUTER establishing data channel based on the configuration of the monitoring center network in the IP address with the monitoring center. CDMA terminal connection has yet to be technically better is to support, the practical application of this method is rarely used.

3 3 Contact:Peter Zhang Figure 2 - system topology 2: CDMA network connection How to decide what kind of program, the key is determined by the nature of the application. From the most economical way to consider the monitoring center using "ADSL (Dynamic IP) + dynamic domain name" solution. Connection terminal and the monitoring center is based Socket Communications. Achieve three systems 1 terminal part Terminal portion of the image acquisition by the camera DTU, microprocessor and CDMA RUTER components. Camera DTU is responsible for collecting image data collected by the microprocessor, the microprocessor by CDMA RUTER send data to the remote monitoring center. 1.1 DTU and camera interfaces DTU is a camera with video capture and compression functions of the camera, it functions as a digital camera is very similar. DTU camera using standard compression algorithm compresses the original image JPG format, the compression function to improve the usefulness of remote video surveillance system. DTU camera data interface is RJ45 interface, using a + 5V supply input. Pin function as follows: CAPEN: used to enable or disable the camera DTU output image. CAPEN = 1, allows the output image, CAPEN = 0, then disable the output image. JPEGD7..JPEGD0: parallel data output. 8 output image data in this group of pins. JPEGINT: DTU from the camera to an external microcontroller interrupt signal is a positive pulse width of about 10us, the microcontroller can trigger an interrupt on the falling edge of this signal. This interrupt signal indicates that the output has a new image data on the JPEGD7..JPEGD0 pins. DTU camera has an internal reset and initialization process after power enters the standby mode after initialization is complete. In the standby mode, the camera DTU loop checks CAPEN pin, if CAPEN = 1, in the JPEGD7..JPEGD0 pin continuous

4 4 Contact:Peter Zhang output data, each output data, to generate an interrupt signal on JPEGINT pin to notify the micro The controller reads the data. DTU camera output is a complete JPG file, JPG file is always "0XFF", "0XD8" start and "0XFF", "0XD9" end. The microcontroller checks the received data, when receiving "0XFF", when "0XD9", indicates that the file end, this acquisition is complete. Then the camera DTU will return to the standby mode. Microcontrollers TMS320LF2407A, clocked at 40M, IOPC mouth used to read data DTU camera, camera DTU interrupt output (CAPINT) connected to TMS320LF2407 of XINT1, falling edge; output enable (CAPEN) connected IOPE0. TMS320LF2407 expanded 64K bytes of SRAM as an image cache. Because the camera is used DTU +5 power supply, TM320LF2407 uses a + 3.3V power supply, so the interface must solve level conversion. In this paper, SN74LVC245A chip to achieve the + 5V supply and a + 3.3V power supply system mobile. Level translation between systems. 1.2 CDMA transmission section After the microcontroller to collect image data to be transmitted to the control center via the Internet data. The complete system microcontroller and Internet network communication work is CDMA RUTER and CDMA network. Because CDMA is based on IP protocol, but ordinary CDMA RUTER no embedded TCP / IP protocol stack, the need to provide TCP / IP support for users. That is, the need to embed TCP / IP in CDMA RUTER use of PC systems, this is a complex and tedious work. In order to reduce the workload of the application itself and increase the practicality of the system, the system uses the Xiamen Caimore Communication Industrial CDMA RUTER, model CM6550R, which is embedded with TCP / IP protocol stack, with Socket communication, and provide transparency data transmission channel, the user can set some parameters can realize embedded systems connected directly to the Internet, to achieve network interconnection. The main features of CDMA RUTER easy to use, flexible, and reliable; embedded in a complete TCP / IP protocol stack, including PPP, TCP, UDP, Socket, STMP, etc; supports RS-232 and Rj45 Interface; After power automatic dial-up, has been online, disconnected automatically connect;! Leading communications technology forum 9g f2} 9t & b transparent data transmission mode, the parameters can be set freely;

5 5 Contact:Peter Zhang MSCBSC Mobile Communications Forum; ~ -d7b; u & c4b8t (L: ~ 5y) D support dynamic data center domain names and IP addresses; 7h M ) _, k! support for audio interface for easy maintenance operations;% g; h5t2b6h'r6f &} A2Q! System configuration and maintenance interface; Power interference and heat dissipation, harsh working conditions; Before using CDMA RUTER must set parameters to decide to enter transparent data transfer mode works. Parameters need to be set are: the monitoring center IP address (or dynamic domain name server can resolve the domain name) and port number; Socket communication type (TCP or UDP); communication interface parameters; trigger mode settings. CDMA RUTER after each boot automatically dial the access CDMA and dynamically obtain an IP address, this IP address is CDMA backbone network addresses, without entering the connected state, the server (monitoring center) is not directly communicate with the CDMA RUTER a. CDMA RUTER initiative to connect to the server to send the data. When the connection route is established, the server and the terminal can double the site for data transmission. The route has a time limit, generally only tens of seconds, in order to ensure that the link has been smooth, CDMA RUTER has a link keep-alive function, by regularly sent: "Heartbeat" packets, maintain routing (dynamic IP by the terminal and the server ISP service providers to dynamically allocate server, if a long time do not communicate, ISP server will reclaim IP, in order to facilitate the effective use of IP resources) to ensure timely mutual communication between the server and the terminal, so the monitoring center can actively sends data to the image capture terminal acquisition command and other parameters. In addition, the "heartbeat" packet contains the ID information of the terminal, so the server can easily determine industry source routing and data packets. 2. Construction of the monitoring center In this paper, the monitoring center using ADSL connection, because the IP address each time you connect acquired is not fixed, CDMA RUTER not directly point to a remote monitoring center. To address each time you connect the server IP address is not fixed, we use a dynamic DNS solution. DDNS function, namely to achieve a fixed domain name to resolve dynamic IP addresses. Internet monitoring center after each get a new IP address, the computer installed in the control center of the dynamic domain name software will put the IP address to the dynamic DNS server, update the DNS database. CDMA RUTER initiated by the domain Socket connection, dynamic DNS server returns the correct IP address to it. Firewall Control Center and the Internet to shield out all unused ports, thus ensuring the safety of the control center, the firewall machine may be a software firewall, it can also be a hardware firewall. In this paper, the control center software can be VC / VB / Delphi written internal DLL in Sang-technology, used to complete the preparation Socket program. Basic control center software flow chart shown in Figure 4. Socket port control center

6 6 Contact:Peter Zhang responsible for the listener listens for connection requests image collection terminal, when listening to a connection request to establish a communication link, the original is still responsible for monitoring Socket listen, you can exchange data after any communication link was established. Monitoring center software should have ID display terminal on the monitor screen and multiple images on the hard disk, and storing the image display different terminals. Through the image analysis and processing, such as abnormal alarm signal is given and the alarm information to the remote terminal to activate the alarm device to prevent vandalism, theft and the like. Related managers can be viewed directly monitor site, and feel free to tune to see the current state of each terminal. 4. Conclusion With increasing levels of production management, remote video remote monitoring has been widely used, more and more mature, and is moving network, intelligent direction. CDMA wireless transmission of data using the communication method to solve the communication problem of remote monitoring system, compared to other wired communication has incomparable superiority. Since the transmission of the image data, the amount of data and more frequent, may choose not to limit the use of business packages more economical. Our laboratory constructed in the wireless video remote monitoring, to obtain the desired results. Moreover, with the gradual improvement of mature CDMA network and application technology, CDMA applications will be more broad. CDMA wireless transmission system presented here can be extended to a variety of needs testing, monitoring and security of the environment.