Views:15 Author:Site Editor Publish Time: 2020-06-10 Origin:Site
(1) Flexible networking, each base station's turntable usually works on its own channel. If there are major tasks that require multiple base stations to be networked, each simulcast base station can be set to one or more simulcast groups through the network management center. Forming a simulcast network or multiple simulcast networks, the network responds to each other to facilitate unified command and dispatch.
(2) Low investment, strong practicability, easy to achieve good coverage in a large area, and wireless communication in the region; the repeater of the simulcast system only needs to be installed in a relatively high location, away from high-power transmitting equipment.
(3) The system has simple and reasonable structure, high reliability, strong operability, and has the functions of command and dispatch, management and maintenance, remote monitoring and so on.
(4) Multi-directional coverage to eliminate communication blind spots. The simulcast network can not only expand the coverage, but also effectively solve the wireless blind zone problem. Because multiple relay stations can achieve multi-directional coverage, the location of mobile users may be hindered by one or both parties. At this time, relay signals in other directions can be injected, and users can still get good communication effects. .
(5) Even coverage and stable signal. The wireless simulcast network is covered by multiple points, and the field strength of the entire coverage area is average, so the communication effect of the simulcast network is stable and reliable.
Since the 1980s, dedicated wireless communication for command and dispatch has begun. Governments and industry departments such as public security, armed police, electric power, railways, civil aviation, and forest fire prevention have begun to form their own wireless command and dispatch networks. The national radio management department has planned special frequencies for relevant departments, and the wireless communication private network has entered a period of rapid development. In the 1990s, the State Non-commissioned Commission planned a 350-megabyte frequency dedicated to public security for the public security department, which was used to form a 350-megabyte cluster communication network for police. By 2010, public security agencies at all levels across the country had basically established a 350-megabyte special police cluster. Communication network. The armed police, power, railway, civil aviation and other departments have basically established their own wireless command and dispatch networks. 1980 to 2012 is a period of rapid development of analog wireless conventional and analog trunking communication networks.
Due to the small coverage of a single wireless conventional communication network, it is difficult to meet the service requirements of large-scale and wide coverage of China Unicom. However, the analog trunking communication network has the disadvantage of weak hand-off capability and the system of different manufacturers cannot be interconnected. Simple, wide coverage, high reliability, low construction requirements, etc., can be used as the main network, can also be used as a backup network, has achieved rapid development. One is that the same-frequency simulcast can achieve large-area coverage. There is no need to change channels when cross-regional. There is no trouble such as identity registration in the cluster system. The simplest way to solve the problem of interconnection and intercommunication during cross-regional dispatching and command. The use of the same frequency and simulcast is an inevitable practical choice for various analog conventional and analog trunking systems that are difficult to achieve interconnection and wide area coverage. The second is that analog conventional/cluster terminals are widely popularized. It is the simplest and most realistic choice to realize the inter-regional (cross-system) interconnection and transmission through narrow-band frequency modulation transmission of analog voice. The same frequency simulcast can continue to use the existing analog conventional/cluster terminal. Whether it is invulnerability, construction and operation and maintenance costs, or terminal penetration and comprehensive application performance, the analog co-simulcast system covered by the large-area system is undoubtedly the best realistic choice at that time.
The period from 1998 to 2012 was a period of rapid development of analog wireless communication, and also a booming period of co-channel simulcast development. For example, the public security department, while many cities have built a 350 trillion police analog cluster communication network, they have also built the same frequency simulcast network as an emergency network backup. The command and dispatch of China has built a provincial or municipal level co-simulcast emergency dispatching network. For example, Guangdong Province has built a province-wide public security emergency dispatch co-simultaneous broadcasting network; there are also some places that plan to build a digital trunking communication network, which uses co-simultaneous broadcasting The broadcast network is a transitional command and dispatch network. For example, the Shenzhen Public Security Bureau built more than a dozen of the same frequency simulcast network for daily communication and dispatch of various police types around 2000; also with the development of highways and urban rail transit The same frequency simulcast network is also quickly applied to the communication command of highways and urban rail transit. For example, the expressway branch of Hunan Provincial Traffic Police Corps has built a provincial highway 350 megabyte simulcast simulcast cluster communication network. The analog co-simulcast network develops with the development of analog wireless communication.