Wireless transmission technology system introduction

With the development of video surveillance, the video surveillance market has gradually evolved from intelligent intelligence and network development from the beginning, and wireless transmission technology has become the mainstream of video surveillance, from SD to HD. The rapid evolution of wireless transmission technology is the fundamental driving force for the development of the wireless monitoring market. In many fields, wireless applications have made many exemplary and representative monitoring applications. As a link of the network, the wireless network has obvious advantages that the wired network is irreplaceable. The network construction is convenient and flexible, the cost is low, the user investment is protected, and the use is reliable.

Wireless transmission technology classification

Currently available wireless transmission technologies mainly include 3G, WiFi, and GPRS. First, the differences between these three technologies are introduced:

3G: For the current Category 3 3G technology, China Mobile's TD-SCDMA has a small bandwidth and rarely uses this technology for transmission. Generally, Unicom WCDMA and Telecom's CDMA-2000 (EVDO) are adopted as the main 3G standard for public transportation of public transportation;

WiFi: According to its speed and technology, it can be divided into 802.11a, 802.11b, 802.11g, 802.11n,

GPRS: Different from the previous way of continuously transmitting channels, it is transmitted in packets, and the transmission rate can be increased to 56-114Kbps.

These three technologies are the current common wireless transmission technologies. Among them, 3G networks are the most common and are the main carriers for real-time transmission. After the support of the country in recent years, China's 3G network coverage is becoming wider and wider, in large and medium-sized cities and The surrounding area has been built, and its theoretical bandwidth is above 2Mbps, which can meet the real-time transmission demand of bus definition SD video stream. The network bandwidth of WiFi is much larger than that of 3G bandwidth, but the construction area is narrow. Even in large cities such as Shanghai, it can not realize the full coverage of its network, which is not conducive to the real-time transmission application of public transportation monitoring data. The 3G network traffic transmission video signal traffic is high. In order to make up for the shortcomings of 3G wireless bandwidth, the bus company will usually set up a WiFi network at the station. When the bus enters the market, it will automatically switch to the high-bandwidth WiFi network for large-scale data transmission. Can not meet the needs of real-time monitoring.

The bandwidth of GPRS wireless transmission technology is the lowest of the three. When the network is good, it is only 10~100 Kbps, which can not meet the real-time transmission of ordinary video stream. It is generally used for frame transmission or alarm information release; the network is not good. In the case, the on-board server will automatically select the GPRS network to preferentially transmit alarm information. In addition, there are 2 generations of network GSM transmission technology. Due to the extremely small bandwidth of this technology, it is only a few Kbps, but its network coverage is very wide. It is still the mainstream wireless transmission technology. It can be used in areas that cannot be covered by remote 3G networks. This technology transmits the vehicle's driving state intermittently or continuously.

Wireless video surveillance application

Small-scale monitoring: Small-scale wireless monitoring, used in office places, factories, warehouses, etc., with fat APs and thin APs without access as the center, combined with the original wired network to achieve video transmission. The main scenes are: buildings that are not convenient for rewiring; if wired monitoring is used, it may cause damage to the original building, requiring trenching, embedding, etc., so it is not convenient to use traditional wired monitoring.

For small-scale monitoring, because there are fewer monitoring points, the video bandwidth of the access is relatively narrow. Under the condition that the management requirements are not emphasized, the network camera and NVR products with wireless access can be selected to design a relatively economical wireless video surveillance. system.

Large-scale monitoring: highways, forests, remote mountainous areas, oil fields, scenic areas, power, water conservancy and other large-scale, long-distance fixed-point monitoring applications; geographically restricted, difficult to route, if using wireless video transmission technology, can make up for cable Monitor the lack of transmission. Therefore, for the above types of monitoring scenarios, we recommend the use of wireless monitoring transmission technology, regardless of stability, traffic, and tariffs have other advantages that wireless can not match.