China needs to establish a satellite mobile communication system to support the mobile communication services of users outside the service area of the terrestrial mobile communication network, and its terminals should be light and low-cost.
Satellite mobile communication systems are also used to provide basic communication (voice and low-speed data, which is more important for developing countries) for rural and remote areas that are not covered by terrestrial communication networks. The "rural and remote areas" users here refer to the very scattered "natural villages", which requires the complexity, volume and cost of their terminals to be much smaller than VSAT small stations.
China satellite mobile communication system APMT (Asia-Pacific Mobile Communication System) is under construction, which is a regional system supported by synchronous satellites. The system supports mobile phone users, so the satellite antenna is very large (the antenna diameter is about 1-3m), and the system is also used to support basic communication in remote areas.
In the near future, China's satellite network will also be used to support the communication needs of high-speed users (group users) in low-density areas, such as high-speed internet browsing and high-speed access to public networks. For this kind of users, the simplification and low cost of their terminal equipment are also very important. Assumption of establishing integrated satellite communication system in China. At present, the development of synchronous satellite communication in China has reached a large scale, which has played a great role in the backup of national trunk communication network and the establishment of private network. However, in the face of some business needs, such as mobile communication services, basic communication services in remote areas, high-speed user access and Internet browsing, and interactive multimedia services, is China adopting a constantly developing and expanding synchronous satellite communication system to support these new services? Or should we establish an integrated satellite communication system including synchronous satellites and asynchronous satellites? According to the development trend of satellite communication abroad, asynchronous satellites with low orbit height have great advantages in supporting mobile communication, basic communication in remote areas and high-speed user access, which can effectively reduce the requirements for terminal EIRP (effective combined radiation power) and G/T value (receiver quality factor) and greatly simplify and reduce the cost of user terminals. Therefore, it is technically reasonable to establish an integrated satellite communication system in China.