The Southern Snow Disaster and the 5.12 Wenchuan Earthquake that occurred in the spring of 2008 posed a severe test on China's emergency communications and disaster backup communications systems. In these two huge natural disasters, the communication network in the disaster area was basically paralyzed with the damage of infrastructure (such as optical cables, copper cables, wireless base stations, switching equipment, and equipment rooms) and the interruption of power supply. Not only that, because of the traffic interruption caused by the disaster at the same time, the emergency communication plan that is usually prepared is also difficult to implement due to the inaccessibility of equipment, vehicles and personnel. Therefore, what the two disasters have in common is that at the critical moment when the disaster just happened, the outside world needs to understand the disaster situation the most, and the disaster area most hopes to report the disaster situation to the superior, communication cannot play its due role. An important reason for this is that China lacks planning and construction of disaster backup communication systems.
1. Differences and similarities between emergency communications and disaster backup communications
Theoretically, disaster backup communications should also be subject to emergency communications in a broad sense, but here, in order to emphasize the importance of disaster backup systems, we prefer to separate the two.
The definition of emergency communication (narrowly defined) in this article refers to: in the event of a major disaster causing damage to the original local communication facilities, restore local communication through some temporary means of communication; or under special circumstances, according to government instructions or needs The act of providing temporary means of communication in areas where there is no means of communication. The "emergency communications" mentioned below are all narrow concepts.
For disaster backup communication, it mainly refers to the use of mainstream communication means as well as the backup and supplement of mainstream communication means when constructing and designing communication systems. When mainstream communication means are interrupted due to a disaster, The ability to use backup methods to continue to protect the most basic communication needs.
The common point between emergency communications and disaster backup communications is that they are all means to provide temporary communication links to disaster-stricken areas or units when mainstream communication methods are blocked due to disasters or other reasons. The difference is that emergency communication is usually after the original communication means is interrupted, and then other means are used to restore the communication, including the restoration of the mainstream communication network. Therefore, the nature of emergency communication is mainly to repair the dead; disaster backup communication is to prepare for the possibility of interruption of mainstream communication means before the disaster, so as to ensure that the communication of the relevant area or unit is not blocked when it is affected by the disaster And maintain minimum external contact. Therefore, the nature of disaster communication backup is more of a precaution. The relationship between emergency communications and disaster backup communications should be complementary and indispensable.
2. Analysis of the main reasons for the communication network interruption caused by natural disasters
According to the actual situation of the Southern Snow Disaster in the spring of 2008 and the 5.12 Wenchuan Earthquake, the main reasons for the interruption of communications caused by natural disasters are the following four points.
(1) Disasters cause damage to infrastructure (such as optical cables, copper cables, wireless base stations, switching equipment, and computer rooms), and cut off the communication network in the disaster area, especially the main communication trunk line with the outside world;
(2) The power supply was interrupted by the disaster and the communication facilities were paralyzed;
(3) Disasters cause simultaneous interruption of traffic, making it difficult for emergency communication equipment and personnel prepared in advance to enter the scene;
(4) Disasters cause panic among people in disaster-stricken areas, so that even if the local communication network is not damaged, the network will be paralyzed due to a large number of calls and traffic that far exceed the design load of the local access network. Makes the most urgent information difficult to send.
At the same time, according to the actual situation of the two disasters, when the disaster just happened, although the above four events are of different degrees, they often happen at the same time, not only paralyzing the original communication network in the disaster area, but also making the emergency communication means to restore the disaster area Communication has also become quite difficult, and as a result, the disaster area has been unable to resume normal communication for a long period of time and has been isolated from the outside world.
3. Analysis on the means of emergency communications and disaster backup communications
According to the above analysis, when designing emergency telecommunications and disaster backup communications or formulating relevant plans, we must carefully consider the impact of four factors such as relay, power, transportation, and overloaded traffic.
At present, the available methods for emergency communication and disaster backup communication include wired and wireless. Among them, the wired method is mainly provided by a detour circuit or a temporary circuit, and the wireless method can be subdivided into digital trunking and wireless cellular. , Wireless LAN, WiMAX, microwave, and satellite communications, among which satellite communications can be subdivided into satellite mobile communications, IDR, VSAT, and IPSTAR satellite broadband. At the same time, according to the transportation method, satellite communications can be divided into handheld, vehicle-mounted, portable, and fixed terminals.
Comparison of the above methods.
(1) In terms of long-distance trunking, terrestrial optical and copper cables have the advantages of large capacity and high cost performance, but they are easily damaged by natural disasters such as earthquakes and floods. Therefore, in the event of a disaster, it is a better choice to use microwave and satellite communications as the relay circuit backup;
(2) In terms of power, when disasters lead to large-scale power outages, according to actual experience at home and abroad, in addition to carefully designed cluster systems (such as NEXTEL in the United States September 11 incident), it is possible to use backup methods to supply power to base stations. Due to the cost problem caused by the scale of other wireless systems, it is difficult to provide backup power for all wireless base stations and microwave relay towers; satellite communication has the lowest power requirements due to its own system. It is only necessary to equip the relevant satellite terminal with a small portable generator or solar battery in advance to provide basic external contact for the relevant area or unit when a disaster occurs;
(3) In terms of solving the impact of traffic interruption on communications, once a disaster occurs, no matter how light and flexible emergency communication methods (including satellite mobile phones) also need to be after traffic recovery (including the use of unconventional transportation methods, such as this time (Helicopters used in earthquake disasters) can be transported into the disaster area. In order to avoid the embarrassing situation of communication recovery relying on traffic recovery, only by preparing for disasters before the disaster and establishing a disaster backup communication system can communication be ensured without interruption after the disaster;
(4) Regarding the impact of network congestion caused by post-disaster panic on key communications, there are only two methods so far. One is to establish a special emergency command communication system for government departments or enterprises, which is not related to civil networks, and currently uses digital trunking. System; another is to establish a government or enterprise satellite disaster backup communication system, because when satellite communication is used as an access network, because there is no connection with the local access network (whether wired or wireless), the phone or data is on the satellite Directly reach the satellite communication gateway station located in a different place or connected to the local long-distance office, so you can avoid the local network congestion caused by panic after the disaster.
In summary, satellite communications are the most suitable means for emergency communications and disaster backup communications. In normal times, simply comparing satellite communications with terrestrial telecommunications services, satellite communications are at a disadvantage in terms of capacity and cost performance, but when disasters occur, optical cables are destroyed by earthquakes and floods, terrestrial wireless communications are damaged, power outages or loads due to base stations When it is too heavy to stop working, when the disaster area urgently needs to report the disaster situation, and the outside urgently needs to understand the situation of the disaster area, the satellite emergency communication system, especially the pre-designed and equipped satellite disaster backup communication system will be able to ensure the availability of key information Released to save more lives and property.
4. The application of IPSTAR satellite broadband communication system in disaster recovery communication and emergency communication
4.1. Composition of IPSTAR broadband satellite communication system
The IPSTAR system introduced by China Satellite Communications Corporation is the first broadband satellite communication system put into practical operation in China. The IPSTAR satellite was launched in August 2005 and was subsequently put into use, bringing China into a new era of broadband satellite communication. Provide 12Gbit / s transmission capacity. The IPSTAR system is completely designed based on IP and is an all-IP satellite communication network. The IPSTAR system operated by China Satcom is composed of three IPSTAR gateway stations constructed in Beijing, Shanghai and Guangzhou and IPSTAR terminal stations spread all over the country.
The IPSTAR gateway system is the core switching node of the system, providing Internet access, VoIP phone switching and various content services for IPSTAR end stations. Establish optical fiber cables or other communication media connections between the three gateway stations to carry out unified and coordinated operation and management, thereby achieving nationwide communication exchange capability.
The IPSTAR gateway is connected to the main domestic backbone network, which allows IPSTAR users to bypass the multiple router connections of the ground network. The distance between each IPSTAR user and the backbone network is greatly shortened, which can fully guarantee the quality of Internet data transmission. The IPSTAR gateway is equipped with an advanced VoIP platform, which can provide SIP-based IP voice services for all IPSTAR users. At the same time, it can communicate with ordinary fixed phones and mobile phones through the interconnection interface between the IPSTAR gateway and the public telephone network. Communication.
4.2. Application of IPSTAR broadband satellite communication system in disaster preparedness communication and emergency communication
In satellite communication methods, each communication method has its own characteristics. For example, satellite mobile communication has the characteristics of flexibility, lightness, and portability. It is suitable for emergency communication occasions, but only suitable for personal communication. The IDR has a large communication capacity and is suitable for providing communication trunk lines for wireless cellular or terrestrial access networks. However, due to its price, volume, weight, and power consumption, it lacks flexibility and mobility and is not easy to be fully promoted. VSAT often appears in the form of a private network, and the system capacity is limited. Except for the network used for public telecommunications services, it is generally isolated from mainstream telecommunications networks. Some VSAT communication master stations are located in this province, and are also vulnerable to disasters when disasters occur. The IPSTAR satellite broadband service is characterized by large capacity, which can accommodate up to hundreds of thousands of users. Its design itself is to provide public telecommunications services. Due to its IP-based features, a terminal can simultaneously provide voice, data, and video transmission in the disaster area. Integrated telecommunications services, while weight and volume are suitable for transportation and carrying.
The main application forms of the IPSTAR satellite broadband service are as follows.
1. Satellite broadband telephone
China Satellite Communications can provide broadband phones based on the IPSTAR broadband satellite system by integrating relevant communication resources and using advanced softswitch technology.
When IPSTAR satellite broadband is used in emergency communications and disaster backup communications, it has the following characteristics:
Each terminal of IPSTAR can provide 2-8 channels of telephones at the same time, and can also serve as a relay circuit to provide up to 64 relay lines at the same time.
As the calling party, IPSTAR can access PSTN, PLMN and other public communication networks through China Satellite Communication's NGN network.
IPSTAR can provide the called number to be directly called by PSTN and PLMN.
2. Internet access
The IPSTAR broadband satellite communication system is based on IP technology, and a single satellite end station can connect multiple computers to the Internet, as shown in the following figure
3. Video transmission
The IPSTAR broadband satellite system can provide up to 2Mbps upload capability. By configuring camera devices and codec equipment, the on-site situation in the affected area can be transmitted to the headquarters for disaster relief organizations.
(1) Satellite single hop, backhaul via the Internet
(2) Satellite single hop, via ground dedicated line
(3) Satellite double hop
4. Data transmission
Similar to video transmission, IPSTAR broadband satellite communication system can also transmit various monitoring data, such as hydrological monitoring data, seismic monitoring data, etc. Similarly, there are two types of transmission: satellite single-hop transmission and satellite double-hop transmission.
(1) Satellite single hop, data transmission through dedicated line
(2) Satellite double-hop data transmission
(1) Application examples of IPSTAR broadband satellite communication system in earthquake relief
1. Application of communication integration in Yingxiu Town
China Satellite Communication established a satellite broadband emergency communication system between Yingxiu Town and a certain group army disaster relief headquarters through a portable IPSTAR satellite broadband terminal. The first real-time rescue picture of Yingxiu Town was returned to the Sichuan Earthquake Disaster Relief Command Center for disaster relief command. The Ministry provided timely and accurate communications for disaster relief, health and epidemic prevention, and post-disaster reconstruction work; at the same time, it also provided satellite and Internet return means for news and pictures to the news media interviewed in the disaster area; Free satellite IP telephone service is provided.
2. Provide video backhaul for media and TV stations
In the disaster relief work in Sichuan, it provided live broadcast of the disaster area for CCTV network; provided live broadcast, video backhaul and information transmission channel for Shanghai Oriental Satellite TV, Chengdu TV station and other media.
China Satellite Communication technicians rushed to the Zundao Primary School and Zundao Shenyang Hospital in Mianzhu County, Deyang with CCTV International Network and News Channel reporters to conduct a live broadcast of "I am on the spot" via a satellite two-way video voice system.
3. Video monitoring of Tangjiashan dammed lake
During the emergency rescue process of Tangjiashan Barrage Lake, 10 unattended satellite broadband water regime monitoring points were set up for the Tangjiashan Barrage Lake Command, and the video images of all hydrological disasters in the waters were transmitted to the Mianyang Hazard Evacuation Command and the State Council. The rapid decision-making and command of emergency rescue work provides scientific and accurate judgment basis.
The video monitoring situation of Tangjiashan dammed lake water transmission by broadband satellite
In short, after experiencing the southern snow disaster at the beginning of the year and the Wenchuan earthquake in Sichuan in May, it was painful and painful. The construction of China's emergency communication system, especially the disaster backup communication system, should or has attracted the attention of government departments and relevant units at all levels. In view of the comprehensive advantages of the IPSTAR satellite broadband system that has withstood the Sichuan earthquake relief work, it will surely play its unique role in the construction of emergency communication and disaster backup communication systems in China in the future.
Sensor Trash Can,Foot Sensor Automatic Dustbin,Foot Sensor Dustbin,Foot Sensor Trash Can
NINGBO ZIXING ELECTRONIC CO.,LTD. , https://www.zixingautobin.com