In recent years, with the continuous development of the high-definition era, people are constantly pursuing a clearer and faster visual experience. However, in the wireless monitoring system, the transmission of higher definition video images must be supported by a wireless bridge with higher bandwidth. If your wireless video transmission equipment cannot meet the demand for high-definition transmission, it will cause delay in the wireless monitoring system.
The delay of the wireless monitoring system is often a problem that most customers worry about. The greater the delay, the smoother the wireless monitoring system will be, which will lead to the transmission of video images stuck, or even video images sometimes absent. However, many customers attribute the delay to the wireless bridge. In fact, we need to find the reason not only from the wireless bridge, but also from all aspects of the system. Wuxi Dehang Technology Co., Ltd. will introduce in detail the six important factors that cause the delay of the wireless monitoring system:
1. Impact of wireless bridge performance
Usually, when the wireless monitoring system has a delay, we need to check whether there is a delay in the wireless bridge itself. For some low-end products on the market, the net bandwidth cannot meet the requirements of high-definition video transmission, which will lead to a large delay when transmitting video signals. And its CPU processing performance, matching system speed, antenna quality, etc. can seriously affect the transmission speed. Therefore, when we choose a wireless bridge, we should choose a wireless bridge that has enough bandwidth, enough chip processing capacity, and enough gain to ensure that you have no worries in the use of the wireless monitoring system.
2. Influence of wireless monitoring system network cable performance
As we all know, the network cables in the wireless monitoring system are divided into five types of network cables, super five types of network cables and super six types of network cables. Previously, the use of five types of network cables for transmission in the standard definition system can fully meet the needs. In the high-definition wireless monitoring system, we need to use CAT 5 network cable and CAT 6 network cable to achieve image transmission. The CAT 5 network cable supports a bandwidth of 100m and CAT 6 network cable supports a bandwidth of 500m.
However, we should not only pay attention to the selection of network cable types, but also to the length of the network cable. The length of the network cable from the POE to the wireless bridge should not exceed 30 meters. If it is too long, the signal attenuation is too large. And the network video camera The length of the network cable to the wireless bridge is generally within 90 meters Switch The length of the network cable between them is also within 90 meters. If you need to transmit a longer distance, it is recommended to use optical fiber for transmission.
3. Impact of front-end camera performance
In the wireless monitoring system, the selection of cameras is also very important. If the CPU processing capacity of the monitoring camera or the overall system response speed of the monitoring camera is insufficient, delay will occur. Therefore, when the bandwidth is fixed, the need to transmit 1080P/60 frame HD video requires some special video processing chips to improve the compression rate of video coding, which can effectively reduce the volume of data to be transmitted and reduce latency.
4. Impact of switch performance
In wireless monitoring systems, switches are often a part that is easily ignored by users. Many people will think that switches only carry out packet forwarding and do not need to process data packets, so the performance of switches is not so important. In fact, this idea is wrong. If you are transmitting network signals, most switches can meet your needs because the uplink and download bandwidth of the network itself is not large. In the wireless monitoring system, the bandwidth of the video images transmitted by the wireless monitoring system is relatively large. If the packet forwarding rate of the switch you use fails to meet the transmission requirements, the switch will have insufficient processing capacity, which is prone to delay, packet switching, and other situations.
Therefore, when selecting a switch, we must determine the total bandwidth of the data collected by your front end, and then select the switch that is suitable for you according to the backplane bandwidth of the switch and the packet forwarding rate. At present, there are many kinds of switches on the market, which are used for civil and industrial purposes. So when you buy a switch, you should not be greedy. You must choose a special monitoring switch to build a wireless monitoring system.
5. Network Digital Video Recorder Performance impact
Network hard disk video recorder not only stores and records the transmitted video image, but also decodes the video signal at the front end. The decoding speed of the decoder is insufficient, which will cause the delay of the wireless monitoring system. Although decoder plays a small role in generating delay problems, we cannot ignore its impact.
6. Influence of transfer times of wireless monitoring system
When the wireless monitoring system is built, the wireless monitoring system must be in an unobstructed environment to ensure the stable transmission of signals. If the transmitter and receiver are blocked, the wireless monitoring system will be delayed and the transmitted video image will be unstable. In this case, we will use relay to avoid obstructions. However, the more hops, the more losses and delays will occur in the wireless monitoring system.
Therefore, when you design the wireless monitoring scheme in the early stage, you must choose the position of the transmitter and receiver. If you can mount high, the two ends should be as high as possible to avoid obstructions. The selection of relay is just the next best choice.
If there is no way to reduce the number of transfers, we can choose some devices with less loss in the jump process to be used in the MESH network with more hop nodes.
LA-8000DHC is a wireless MESH network product with ad hoc network characteristics, with a Mini PCI high power wireless network card. It is widely used for mobile network data transmission such as UAV image transmission, individual equipment, cruise ship, rail transit, railway, emergency command, driving school subject II, subject III, mine transportation, patrol detection, factory mobile transportation, etc. It has online intelligent scanning, multi-path connection, intelligent path learning and other functions, and can provide high bandwidth Low latency data roaming service.
