Broadband China, a popular keyword on the Internet for many years, but the actual network quality is not so hot, is it the inaction of telecom operators? Nor can it be all blamed. The country has launched a broadband strategy. It is obviously not enough to stay on paper.
With the confusion of broadband development and the complaints of netizens about network speed, Tencent Technology visited Wuhan, China's first birthplace of optical fiber, and tried to find answers here.
Wuhan is an important research and development base for the optical communications industry and one of the most important communications hubs in the country. It is also the third largest business command and dispatch center of China Telecom, with the fourth largest network capacity in the country, directly interconnected with the three super cores of Beijing, Shanghai and Guangzhou, and provides access to Hunan, Jiangxi, Guangxi, Shaanxi, Hainan, Yunnan and other provinces Become an outlet for these provinces to access the Internet. Wuhan as a core node provides high-quality Internet services to Hubei broadband users.
When it comes to fiber optics, we must mention the flame. Academician Zhao Zisen, the father of China's fiber optics, said in an exclusive interview with Tencent Technology that in 2013, China's broadband penetration rate was less than 7%. The development of China's broadband industry is not a technical issue, but an economic issue, limited network construction funds, and users The monthly fee is too high, and users cannot afford broadband. Broadband China's strategic countries still need strong support.
Although broadband speeds have been significantly improved everywhere, the problem of "fake broadband" that has been plagued by users still exists, and the speed-up target set by the "Broadband China" strategy is being flooded.
In this regard, the second station visited by Tencent Technology is China's largest broadband service provider-China Telecom. From the branch company Hubei Telecom Tencent Technology visited this time, we learned that Hubei Telecom took the lead in starting a pilot project of fiber-to-the-home construction in a newly built community in Wuhan in 2005, thus unveiling the commercial prelude of China's "fiber-to-the-home". In 2006, the National Development and Reform Commission's High-Tech Industry Department defined Wuhan's "promotion of triple play and fiber-to-the-home" project as the "Wuhan model."
At the end of 2011 and August 2013, Wuhan launched the second and third city-wide network speedups in succession, implemented large-scale FTTH home renovations, and launched free activities or discounts through the launch of "100M broadband into homes" and other activities Substantially increase user broadband. Up to now, Hubei Telecom's fiber-to-the-home project in Wuhan has invested more than 3 billion yuan. FTTH fiber-to-the-home projects cover more than one million households and 3000 communities.
Although there are achievements, the problems facing them also exist. According to the relevant front-line technicians, broadband speed-up is actually a complicated process. In addition to increasing the user's broadband access speed, it also needs to increase the broadband bandwidth of the entire cell and the speed of the backbone network. And to make these three improve simultaneously, it is a huge project for China Telecom, which requires a lot of manpower and financial resources.
For some small and medium-sized broadband and second-tier operators different from China Telecom, they do not have the strength to comprehensively improve broadband speeds, nor do they have the ability to speed up backbone networks. Therefore, the so-called high-speed broadband provided to users is actually a "shared broadband" that makes users hateful.
Obviously, the implementation of the Broadband China strategy is still inseparable from the country's substantial support, especially funding.
In foreign countries, the national injection of funds for broadband has already been implemented. For example, the United States has established a broadband support fund, the Japanese government provides interest-free loans to broadband operators, the Swedish government bears 1/2 of the rural broadband network construction cost, and the local government bears 11%. The government's support for broadband strategy is indispensable for both policy and funding.
In August this year, the long-established national broadband strategy was officially released. According to the strategic plan, by 2015, urban fiber-to-the-floor households will be basically implemented, rural broadband will enter rural areas, villages will have a fixed broadband household penetration rate of 50%, and administrative village broadband will reach 95%; urban and rural households will have basic broadband access capabilities Reached 20Mbps and 4Mbps, some developed cities reached 100Mbps. The goal is to achieve 400 million fixed broadband users by 2020, with urban and rural broadband access capabilities reaching 50 Mbps and 12 Mbps, respectively.
First of all, this is a good thing. At least the country has upgraded broadband China to the will of the country, and it will surely receive further policy support during the implementation process.
Prior to this, broadband construction was led by operators who were responsible for investment implementation, limited to financial pressure. Operators will give priority to construction in some southeastern regions with good return on investment, while broadband construction in the central and western regions is relatively lagging, resulting in obvious regional differentiation. This rise to the national will is expected to comprehensively plan the development of the nationwide broadband construction and give full support in terms of funds, fiscal and taxation policies.
However, two months have passed now, and the specific policy support that operators expect is not synchronized.
According to industry estimates, to achieve the goals set out in the Broadband China Strategy, the three major domestic telecommunications operators need to invest at least 250 billion to 280 billion yuan each year in infrastructure construction. However, in the Broadband China Strategy, the strategy and implementation goals were planned in detail, and the policy support and the universal service fund were only taken several times.
Judging from the existing policy support, telecom operators can only use the existing special funds to provide limited broadband funding support, which is obviously a shortfall.
1. What wireless network
Wireless network, as the name suggests, is a way to build a network without relying on network cables, which is mainly achieved by using wireless communication technology. There are two main ways of wireless network (such as 4G, 3G or GPRS) and wireless local area network (WiFi) through mobile communication networks.
2, What wireless bridge
Wireless bridge, as the name suggests, is the bridge of wireless network, which uses wireless transmission to achieve a communication bridge between two or more networks. In addition to having the basic characteristics of a wired bridge, a wireless bridge works in the 2.4G or 5.8G wireless license-free frequency band, making it easier to deploy than other wired network equipment.
From the function to understand the wireless bridge, it can be used to connect two or more independent network segments, these independent network segments are usually located in different buildings, hundreds of meters to tens of kilometers apart, can be widely used in the interconnection between different buildings.
At the same time, according to different protocols, wireless Bridges can be divided into 802.11b, 802.11g and 802.11n in the 2.4GHz band and 802.11a and 802.11n wireless Bridges in the 5.8GHz band.
3, the meaning of wireless bridge 2.4G and 5.8G
2.4G Bridge:
The advantages are low frequency, large wavelength and strong diffraction ability. Simply put, the propagation performance is good, and the propagation path is slightly shielded. Then there is the relatively low cost.
The disadvantage is that there are many devices using the 2.4G band, and the electromagnetic wave signal emitted by the bridge is easily interfered with the signal emitted by other devices, resulting in a decrease in transmission quality. Moreover, it is limited by the transmission bandwidth of the 2.4GHz band itself, which generally does not exceed 300Mbps
5.8G Bridge:
The advantages are high frequency, relatively pure channel, and large transmission bandwidth. The transmission bandwidth starts at 433Mbps and can easily reach more than 1Gbps. It is suitable for scenarios that require high data transmission.
The disadvantage is that the frequency is high, the signal wavelength is short, the penetration is poor, and there can be no shelter during the propagation. The cost of 5.8G equipment is higher than 2.4G, and it is still in the popularization stage.
Wireless bridge transmission system is usually composed of two or more wireless devices, due to the two-way transmission of data, each device needs to have the ability to send and receive wireless signals.
4, the working principle of wireless bridge
The working principle of the wireless bridge is that the bridge uses the air as a medium to transmit signals, which is simply that one end of the bridge converts the signal in the network cable into a wireless electromagnetic wave signal and transmits it to the air in a directional manner. The bridge at the other end does the opposite, picking up radio electromagnetic signals in the air and converting them into wired signals.
The wireless electromagnetic wave signal can be transmitted by air as the transmission medium, which can solve many problems of difficult construction of wired deployment: such as highways, rivers, mountain streams, or road hardening, and wired deployment and construction difficulties.
Wireless bridge networking has obvious advantages, and can achieve point-to-point or point-to-multipoint network connections at distances of up to 50 kilometers, and data transmission speeds of up to 108Mbps. Effectively solve the problem of network connectivity in the interval, as long as the wireless signal coverage area, the client can easily access the network, the fusion system, without any wiring, the wireless terminal can achieve zero configuration access, so it is very easy to carry out network maintenance and expansion.
Bridges are generally used in the following scenarios: wireless data acquisition, monitoring data transmission (outdoor and elevator), outdoor wireless coverage, outdoor remote wireless bridging, private ISP wireless broadband, unmanned monitoring station data return, etc.
5. How to choose the right bridge
Wireless bridge is a wireless monitoring and transmission equipment commonly used in the field of wireless monitoring, although it is a wireless device like wireless AP and Wireless Router, but it does not need to build wifi coverage, but is used to wireless transmission of video data. Like the switch in wired monitoring, the wireless bridge is an important transmission equipment in wireless monitoring, which is widely used in the two major fields of outdoor surveillance video transmission and elevator surveillance video transmission.
There are many kinds of wireless Bridges on the market, so how to choose a bridge that suits your needs? We will answer your questions from the following aspects.
â‘ Transmission distance
Wireless monitoring projects need to transmit the distance is not the same, wireless bridge transmission distance there are many kinds, some transmission 1~3 km, some transmission 3~5 km, some transmission 5~10 km, some transmission more than 20 km, must be determined according to the monitoring of the transmission distance, as far as possible the maximum transmission distance of the bridge is greater than the monitoring transmission distance, Because rain, fog, snow and other weather in the actual application environment will cause the transmission performance of the bridge to decline, the project construction should reserve sufficient performance margin.
â‘¡ Transmission bandwidth
There are many kinds of transmission rates of wireless bridge, such as 150Mbps, 3000Mbps, 450Mbps, 600Mbps, 900Mbps, etc., which rate to choose can be determined according to wireless monitoring requirements. What users actually need to consider is the transmission performance of the bridge over a specific distance, rather than the theoretical bandwidth data. For example, the theoretical transmission bandwidth of the IP-COM AP625 bridge is 433Mbps, and the actual point-to-point transmission bandwidth can reach 200Mbps at a distance of 2 kilometers, with 25 200W cameras without pressure.
â‘¢ Operating frequency
There are two main operating frequencies of wireless Bridges, 2.4G and 5.8G, and the characteristics of the two Bridges are different. In general, 2.4G wireless bridge is the current mainstream frequency band, good compatibility, good diffraction ability, but the anti-interference is relatively poor, especially in the urban area is vulnerable to wireless signal interference transmitted by other WiFi devices. The 5.8G channel is relatively pure, the anti-interference ability is better, the transmission distance is long, but the diffraction ability is poor.
Urban, downtown, long-distance transmission, camera stream is large, 2.4G interference is more, choose 5.8G wireless bridge. Others such as the transmission distance is relatively close, relatively remote, and the same frequency interference is less, etc. 2.4G wireless bridge is used
â‘£ antenna
Antenna is an important part of wireless bridge, used to transmit and receive wireless signals, no antenna, wireless bridge can not achieve communication. There are many types of antennas, including omnidirectional antennas and directional antennas. Omnidirectional antenna is used for short-range coverage and transmission, and directional antenna should be selected for long-distance bridge. The larger the gain of antenna, the better the performance of wireless bridge.
⑤ Power supply mode
The working environment of the wireless bridge usually involves some complex outdoor environments, such as forests, ports, tunnels, reservoirs and other places, so the power supply is a more troublesome problem. Choosing a wireless bridge that supports POE cable power supply can solve this problem well. IP-COM bridge all support PoE injector power supply, power supply distance up to 60 meters.
â‘¥ Protection level
The wireless bridge works outdoors, the environment is changeable, such as rain, rain and snow, high temperature, etc., the first requirement is waterproof, dustproof, heat resistance, and condensation resistance. For a qualified wireless bridge, these "qualities" are a must.
⑦ Pairing method
At present, there are three mainstream bridge pairing methods: key pairing, dip code pairing, automatic pairing. In terms of the simplicity of engineering applications, especially for projects that install dozens or hundreds of network Bridges at a time, automatic pairing is undoubtedly the best choice. IP-COM network bridge supports the automatic pairing of two network Bridges when they are powered on in the factory state, greatly reducing the workload.
6, wireless bridge installation requirements
Wireless bridge is an important transmission equipment in wireless monitoring, which is widely used in outdoor surveillance video transmission and elevator surveillance video transmission. In addition to selecting the right wireless bridge, we also need the bridge equipment to give full play to its performance advantages after installation to assist users in the project. Therefore, for some installation requirements and precautions of wireless bridge, we should pay more attention to avoid various problems in the later stage.
â‘ Installation height
In the process of wireless transmission, obstacles such as trees, buildings and large reinforced buildings will weaken and block wireless signals. In order to improve the wireless transmission performance and prevent signal damage and weak signal, the user should try to ensure that there are no obstacles in the transmission route of the wireless bridge during installation, and meet the transmission conditions that the two ends can see each other.
Both ends can not be simply understood as point-to-point visibility, which means that there can be no obstacles or potential obstacles in the Fresnel zone (radio wave terminology) in which the antenna is propagated. The main RF energy between the antennas is transmitted in this area, so the transmitting antenna must be high enough above the obstacle to maintain a line of sight path between it and the receiving antenna in order for the communication link to work properly.
â‘¡ Angle and signal debugging
Since the quality of the wireless bridge signal is directly related to the bandwidth and stability of the link, it is necessary to further debug the wireless bridge signal after the installation is completed (the signal strength can be adjusted by adjusting the direction of the antenna on both sides, the pitch Angle, etc.). The signal strength can be checked according to the signal status indicator of the bridge device (three lights, three signals are best, two are average, and one is poor) or the software. Detailed installation procedure for outdoor wireless aps
â‘¢ Requirements for lightning rod
When the wireless bridge is installed in the field, if there are no tall buildings or lightning rod protection nearby, lightning protection measures need to be considered, usually using lightning rod, generally installed in the urban area or surrounded by lightning rod protection, can not be set separately.
It can be seen from the characteristics of the lightning rod that the lightning rod is a lightning source, and the lightning rod will discharge in the grounding path when it is hit by lightning. Therefore, the lightning rod and the protected equipment need to be insulated, otherwise the lightning rod will have a lightning effect on other equipment when discharging. Due to the tip discharge characteristics of the lightning rod, it is easier to cause lightning discharge than the general equipment, so if the lightning rod cannot be isolated from the protected equipment, it will increase the probability of lightning strikes of other equipment. Therefore, the lightning rod grounding must be separate from the device grounding and cannot share the same grounding.
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â‘£ Power supply requirements
The normal input voltage of the PoE power module of the bridge ranges from 100V to 240V and the output voltage ranges from 24V to 48V. If the voltage is lower than or higher than this voltage, the normal operation of the device is affected or the PoE power module is damaged. In view of the unstable and high voltage field power supply, it is necessary to design a PoE power supply solution (such as regulated power supply and UPS power supply) that ADAPTS to the working voltage.
Because the bridge is a precision electronic equipment, it has high requirements for power supply, and is vulnerable to the impact and influence of other power supply equipment, so the power supply of the bridge should be separated from other high-power equipment such as pumping units, oil pumps, etc. When taking power at the same location, UPS, regulated power supply or isolation transformer should be installed to filter out the influence and interference on the power supply when the high-power motor is working.
When the PoE module is used to power the bridge through the network cable, the recommended distance is not more than 60 meters. When this distance is exceeded, it is recommended to move the transmission line near the bridge to meet the recommended power supply distance.
⑤ Device grounding requirements
The wireless bridge should be grounded. If the device is not grounded, the device may run abnormally or be damaged. The grounding resistance of the device should be less than 4 ohms, and the grounding cannot be shared with the lightning rod or strong current line. If PoE power is used, the ground cable also needs to be grounded. Users can ground a Class 5 (or higher) shielded network cable with a ground cable and a PoE adapter to effectively prevent static electricity and lightning strikes. The ground cable and ground point should be waterproof using waterproof tape and waterproof cement according to the waterproof requirements to prevent the ground point from being exposed to the air for a long time, which may cause oxidation or rust.
7, wireless bridge erection method
There are four common wireless bridge transmission modes, the distribution is point-to-point, point-to-multipoint, relay, reflection, here the first monitoring combined with pictures for you to briefly introduce the characteristics of these four wireless transmission modes.
â‘ point-to-point transmission
Point-to-point transmission mode is the simplest transmission mode, that is, we often say PTP, to a single device transmission, and then received by a single device, one-to-one transmission and reception is simple and direct. Point-to-point transmission mode of wireless bridge is often used in the case that the transmission distance is long, or the monitoring point is widely distributed, and point-to-multipoint transmission cannot be achieved.
â‘¡ Point-to-multipoint transmission
The point-to-multipoint transmission mode is developed based on the point-to-point transmission mode, which is often represented as a receiving end to multiple transmitting ends, and is often used for the situation where the transmission distance is relatively close, there are more monitoring points and the distribution is dense.
â‘¢ Relay transmission
The relay transmission mode is because the transmitting end and the receiving end can not avoid the barrier blocking the microwave signal, so the transfer equipment is added in the middle, so that the microwave signal is smoothly transmitted to the receiving end through the transfer equipment, this mode is due to increase the transfer equipment and increase the equipment cost investment, so it is generally not used when unnecessary.
â‘£ Reflection transmission
Reflection transmission is microwave transmission with the help of objects outside the transmission device, such as the transmitting end and the receiving end can not be seen, but there is a large building or a mountain with smooth rock walls in the middle, so that you can adjust the Angle of the equipment, through the building or mountain to reflect microwave signals for wireless communication.
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Shenzhen MovingComm Technology Co., Ltd. , https://www.movingcommiot.com