Based on WiMAx technology of armed police force wireless video surveillance system (1)

0 introduction

Video surveillance system is widely used in the armed police force, the strong promotion of operational readiness of the armed forces.

But there is a wide range of armed troops, such as dams, important warehouses, mineral resource base, bridges, tunnels, decentralized and monitoring points and monitoring center distance, using a traditional wired network video monitoring is often costly and difficult to achieve, and to a lesser extent, real-time video surveillance needs more and more, on the same set of system coverage and implement distance also put forward higher requirements. In these cases, based on a variety of wireless transmission means for mobile video surveillance body appears the irreplaceable advantage. Wireless LAN and wireless broadband access technology, you can apply more than one monitor and remote control center, you can in the shortest possible time to quickly establish wireless monitoring network.

Currently used by the wireless access technologies including Wi-Fi, microwave and WiMAX, etc.

Compared with other technologies, WiMAX have the transmission distance, the access rate, high bandwidth, you can ensure that the video stream transmission quality, while keeping the monitoring and control system at the access layer is more rapid and easy deployment. This article combines the characteristics of the armed forces, made a WiMAX wireless broadband access technology control system design, it also applies to other emergency State organizing monitoring network, and system construction considerations.

1 the technical characteristics and advantages of WiMAX

WiMAX is a new type of wireless communication technology, the full name for worldwide interoperability for microwave access (Worldwide Interoperability for Micro-wave Access), is based on IEEE 802.16 standard broadband wireless metropolitan area networks (Broadband Wireless Access Network, MetropolitanArea BWAMAN) that can provide Internet high speed connection.

WiMAX technology has a high data transfer rate up to a maximum of 75 Mb/s; transmission distance, the maximum transmission radius of 50 km, its network coverage of 3 g base station is 10 times.

1.1 WiMAX systems

WiMAX network architecture as shown in Figure 1, which consists of a core network, base station and user base stations, radio relay station, user terminal equipment and network management.

Usually WiMAX system consists of a base station and multiple user base station, you can set several relay stations, forming a single point-to-multipoint or multipoint-to-multipoint architecture.

Core network: WiMAx connectivity of core network is typically a traditional exchange network or the Internet.

WiMAX provides core network and the connection between the base station.

Base station: provides the user base station and the connection between the core network, usually the fan-shaped antenna or Omni-directional antenna that provides flexible sub-channel deployment and configuration capabilities, and user groups in the escalating extended network.

User base station: belong to a base station, providing a base station and user terminal equipment between Relay connection, usually a fixed antennas are installed on the roof.

Base station and user base station using dynamic adaptive modulation mode.

Relay station: typically used to enhance the base station's coverage, which acts as a base station and several user base station (or user terminal equipment) information relay station.

User terminal equipment: complete specific application features, such as video surveillance.

NMS: are used to monitor and control network in all of the base station and subscriber station, provides query and status monitoring, software downloads, system parameters, configuration, and other functions.

The WiMAX technology for 1.2 armed forces wireless video surveillance system advantages

The armed police force use of video surveillance systems, typically several hundred meters within a monitoring point with wide coverage, coverage and quality requirements.

At present, wireless monitoring system using IP based on Wi-Fi wireless monitoring and control technology, which uses the IEEE standard for wireless transmission 802.11, transmission distance of only a few hundred meters, its data rate is lower, QoS mechanisms incomplete, this limits the application of the armed forces.

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