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WiFi satellites are unreliable, but "Star Wars" has started.

via:博客园     time:2018/12/12 10:21:17     readed:271



Journalist Zhang Galen

Some time ago, some news scrubbed the screen.

The company preparing to launch the satellite is Shanghai Lianshan Network Technology Co., Ltd. According to Lianshang Network, the satellite program

According to information provided by Lianshan Network, this

There were many applauders, but there were also doubts. Xiang Ligang, a communications expert and chief executive of Flying Elephant Network, said, "How much power does it take to connect a mobile phone to a satellite?"

So, is it feasible to use mobile phone to connect satellite WiFi?

Mobile phones can't connect directly to satellite WiFi

The Falcon 9 rocket, developed by US space exploration technology company (SpaceX), has been successfully launched with two microsatellites, the global broadband test satellite developed by SpaceX, and ambitious

Musk, the founder of the company, wishes

Now, you can still see posts like this on the Internet:

In fact, it was just a joke from Musk. Guo Zhengbiao, president of Nanjing Worldwide Space-based Communications Technology Co., said: technically, it is impossible to connect mobile communications equipment such as mobile phones on the ground directly to the so-called satellite WiFi network.

The effective transmission distance of WiFi is usually only tens of meters, but the distance between satellite and earth can be hundreds of kilometers, so the channel environment is completely different.

Moreover, in order to achieve communication, it is necessary to achieve two-way transmission of data. Even if satellites have high-power downstream broadcasting, the upstream power of mobile phones is not so great. That is to say, it is not difficult for the villagers to listen to the loudspeaker at the village entrance, but how loud the voice is if every villager has a one-to-one dialogue with the loudspeaker at the village entrance.

Guo Zhengbiao said that in civil communication services, the use of radio spectrum in space must be declared to the International Telecommunication Union (ITU) to obtain permission to carry out local communication services. WiFi is designed to work in the region, so there will be an authorization-free band in the world. It must work in 2.4 GHz and 5 GHz bands, otherwise it may interfere with other communication devices.

In addition, the frequency bands commonly used by satellites are not consistent with the WiFi band, and the communication standards used are completely different.

Satellite Internet is the Future Trend

Although the WiFi satellite's statement is unreliable, Guo Zhengbiao believes that the provision of communications services over non-terrestrial networks will be the trend in the future.

From the air network

At home, the national team has also entered.

China Aerospace Science and Technology Group launched

In defining 5G service requirements, 3GPP formulating 5G standard also clearly points out that 5G should be able to support all kinds of 3GPP and non-3GPP access (including satellite access); 5G should support land 5G access and satellite access belonging to the same operator or agreed upon by different operators.

Nanjing Worldwide Space-based Communication Technology Co., Ltd. is developing a new space access scheme for satellite-based non-terrestrial networks.

In this regard, Anyang, chief scientist of Lianshang Network Satellite Team, also said that the future communication mode must be the integration of space and earth, and satellite communication will be the complement of ground communication.

Commercial warfare 1,000 kilometres from the Earth

From the actions of Lianshang Network, we can see that social capital is pouring into the field of satellite Internet. In order to occupy a place in this field, capital, technology and resources are indispensable.

Anyang said that the cost of the entire constellation project is expected to be around 3 billion yuan, including more than 2 billion yuan of satellite costs and hundreds of millions of yuan of ground operation and maintenance systems, satellite TT&C and control station costs.

As a company with Internet genes, Lienson has chosen

Guan Hang, chairman of the satellite communications company's cloud-piloted navigation company, told Sci-tech Daily that some private capital had chosen to let users

For satellite communications market prospects, pipeline quite optimistic. He thinks, is the telecommunication service charge this piece alone, contains the huge opportunity.

Wishes are very good, but satellite networking is actually a high-tech job. Many companies are planning to launch satellites, and some are planning to launch a large number of satellites, Guan said. But how many users a satellite can serve depends on its broadband capacity and the company's satellite networking technology. Which means, again,

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