Shulou(Shulou.com)11/24 Report--

The theme of "disaster" seems to have become popular recently, both in the game circle and in the film and television industry. For example, when "the Family of Dragons" hit theaters, HBO released a trailer for the TV version of the famous naughty dog game "the Last Survivor" and announced that it would be released in 2023.

If you want to survive in the course of the game, you need to know how to "communicate". You can hide from the monsters hidden in the dark by making all kinds of gestures and whispering at close range, but if you go out looking for food, encounter attackers, and want to contact the camp, it is almost impossible to use ordinary communication equipment.

Photo Source: the kidnapping and rescue mission of the Internet is also a key factor in promoting the development of the plot. If you notify the camp rescue, the game may not be able to go on.

The most attractive thing about eschatological disaster movies is how to survive in the face of a shortage of modern tools. The modern tools mentioned here refer to devices with communication functions.

Just imagine, in the face of being kidnapped by the enemy and infested with monsters, how can you develop the plot when you use remote satellite communication technology to get a military base to launch nuclear weapons, bombard yourself and directly Game Over? Monsters won't do it.

But then again, it's almost impossible for this scene to happen in the real world, but another kind of "disaster" movie is different.

In the course of watching the movie "fall", which was on fire before, it can make you get a chill behind. The story tells the story of two female masters who climbed a 600-meter-high tower to "heal their hearts". When the heroine A came down, she accidentally broke the ladder connecting the top of the platform, resulting in having to be trapped at the top of the tower to call for help.

Photo Source: screenshot of the movie "fall"

Picture source: screenshot of the "fall" movie they only carry mobile phones, drones for shooting landscapes, and safety ropes of about 15 meters. Under such a difficult environment, they have successively encountered situations that could threaten lives at any time, such as the uselessness of using ordinary flares for help, the failure of drones for help plus no power, vulture attacks, auditory hallucinations due to fatigue, and so on.

Of course, the film ends with a more "satisfactory" film, and the heroine A survives through ropes and some techniques through constant psychological cues and self-encouragement, but her best friend is not so lucky.

As long as the electronic device in hand can work, will there be no such result of one person dying and one person having a mental breakdown?

Satellite communications can really save lives, although movies have certain deductive elements in them, but this approach close to "documentaries" can indeed bring a certain sense of reality. If separated from the film and television, this kind of scene is also typical.

The United States, the wilderness, the sparsely populated area, and the altitude of 600 meters above the ground are all trying to imply that this is an impossible place to signal. On the one hand, it lays the groundwork for the follow-up development of the film plot, on the other hand, it also implies that the signal in the suburbs of the United States is very poor.

It is common sense that there is no communication without a signal.

After watching the movie, I found a discussion on Douban so interesting that an old brother in the comment area directly said, "Huawei mate50 has been here a few months earlier." Of course, joking is teasing, but the reasons behind it make people cry.

The reason is that Huawei and Apple have taken the lead in supporting a feature that can "save" the movie situation: satellite communications.

First of all, we need to answer a question that everyone is concerned about: why, in this extreme case, a mobile phone with satellite communication can send out a request for help, but an ordinary mobile phone signal is not?

RF Wireless World Picture Source: at present, the mainstream mobile phone communication in the network can be divided into two kinds, one is cellular communication, which is also called ground communication, and the other is satellite communication.

In the final analysis, it is because the two "sending and receiving" mechanisms are different. When cellular communication establishes contact with the outside world to send information, it will first be received by the ground wireless receiving base station, and then transmitted over a long distance through wired means, such as optical fiber, and then entered into the network management center and distributed to the base station of the destination. Finally, it is transmitted to the other party's mobile phone.

This most mainstream mode of communication can actually be regarded as wireless-wired-wireless. The most important thing is that the coverage, number and transmission of base stations have the greatest impact on the whole communication transmission link. In harsh environments, such as deserts, Gobi, or environments with a small number of base stations, such as the United States, the deployed base stations and coverage will be seriously affected, resulting in a "no man's land" of the signal.

On the other hand, satellite communication greatly simplifies the transmission process, as long as the mobile phone transmits the information that needs to be sent to the ground base station, and then it will be transmitted to the near-earth satellite through wireless transmission, which is then used as a relay, and then transmitted to the ground base station, and then received by the mobile phone at the other end of the ground, which is a wireless-wireless transmission mode. This advantage is that you don't have to worry about the regional environment at all.

Take the satellite communication function of Huawei Mate 50, which I have used before, for example, this function requires an internal test application at the initial stage, and when the application is approved, you can send "satellite messages" through Changlian App.

Image source: after lzh enters the "Beidou Satellite message" interface, after selecting the content for help and confirming the contact, the user needs to move to the open position after clicking the send button to follow the on-screen reminder. After searching for the satellite, you can wait for more than ten seconds to send the emergency message.

On the other hand, Huawei mobile phones can directly display location coordinates through Changlian App, while phones without Changlian App can also receive text messages with help information and location coordinates. At present, they can only send and receive text messages. After all, in the wilderness, the key is to be able to seek help as soon as possible.

What is the difference between traditional satellite phones and satellite communications between Huawei and Apple? Satellite communication is not a new technology, it can be traced back to the 1970s. Synchronous earth orbit satellite technology, its characteristic is "as its name", the satellite remains relatively stationary relative to the earth, only three satellites are distributed outside the two levels of the world, because of their particularity, they are only used for military communications; and at the beginning of the 20th century, low-and medium-orbit communication satellites have become the protagonist, relying on the high coverage of low-and medium-orbit satellites, the communication delay is greatly reduced, and it is more suitable for handheld devices. Since 2013, it has been operating in very low orbit and has a large number of space-based Internet giant constellations, relying on wider coverage and technical iterative updates to break the circle rapidly, represented by the StraLink project.

In fact, the technology of mobile phone directly connected to satellite has long been "developed by leaps and bounds". Through the mobile communication standard protocol formulated by the global mobile communication standard organization 3GPP, using FPGA to make the software-defined satellite is enough to provide a variety of Internet services for mobile phones, but it is not so mature.

Of course, these satellite technologies are actually too far away from the general public. If you search for "satellite phones" on Taobao now, you may find that this form of phone does not seem to have anything to do with "satellite communications." isn't this a mobile phone with an antenna? Some of the satellite phones, which seem to be "modern", also need a huge antenna.

Pay attention to the source of the antenna size: the network, but the real problem is actually on the phone side. Guo Zhengbiao, founder of the Sat5G satellite communications standard and founder of Worldwide Netcom, said, "if you want a good signal, either make the satellite antenna bigger or make the mobile phone antenna bigger."

It is not difficult to explain why the size and antenna of traditional satellite phones are so large, in fact, it is for the sake of signals, and the signal requirements in voice are much higher than those of short messages.

Image source: the game lzh still has to talk about Huawei's "satellite communications" function. Huawei Mate 50 series "satellite communications" uses China's independent research and development, the first mobile phone Beidou short message communication RF baseband integrated chip, and the antenna part has also been optimized. After all, the current pursuit of thin fuselage consumers, obviously can not accept a prominent piece of the antenna.

If the satellite and mobile phone antennas are enlarged, satellite communications (transmission speed) can reach a few megabytes, equivalent to the previous 3G network.

Of course, it also has something to do with satellites. For example, Tiantong Satellite, which provides services for "mobile phone" satellite phones on the market, provides voice, data and other satellite services, while Mate 50 series satellite communications rely on the short message function of the Beidou navigation constellation, use high-orbit satellites in geosynchronous orbit, and only provide positioning and short message services.

The Apple iPhone 14 series at the other end also supports satellite communications, regardless of the environment or the sending interface, which can be said to be "the same" as Huawei, but it is actually a different matter in the sky.

Photo Source: because the satellite communications in iPhone 14 come from Qualcomm's customized baseband, Qualcomm has a strategic cooperation with American satellite communications company Globalstar, whose global satellite communication system is the low-and medium-orbit communication satellite constellation, which belongs to the near-Earth satellite system.

With more and more capital pouring into the field of satellite communications and gradually entering the mainstream communications market, it is bound to bring a wave of "faster and stronger" development.

Ma Jihua, a communications expert, said, "Mobile phones are directly connected to satellites in the future, and they will be able to connect both low and high orbits. this is the necessity of technological development, but it still needs a process of continuous upgrading and evolution."

However, it is still faced with upstream infrastructure support, satellite number support, insufficient supply of downstream ecological chain, and policy supervision need to be considered.

In February, Geely's Star Times announced that it would launch the world's first consumer phone with a direct connection to a low-orbit satellite as soon as next year, ahead of Huawei and Apple.

In the international market, mobile communication companies such as Verizon, AT&T and Nokia have also reached cooperation with Amazon, OneWeb and AST SpaceMobile.

Google and Apple will not sit idly by, so Google announced that the next generation of Android will also support mobile satellite communications. Apple will also provide satellite communications services through a partnership with Globalstar, which will certainly not be limited to "texting", but will be extended to Internet access.

Source: does this mean that everyone is trying to get their mobile phones to support satellite communications, but in fact they are secretly preparing for being able to "steer" the next-generation communication network?

The White Paper on overall Vision and potential key Technologies of 6G points out that 6G will achieve seamless global coverage of the integration of space, space and earth, and the integrated networking technology of satellite and earth will also become one of the most important potential technologies of 6G network. In addition, many experts in the communication field have said that the future 6G network is actually a hybrid of 5G network and satellite communication, which has the advantages of high throughput and high coverage.

But for the mass consumer market, there is still a long way to go from "emergency help" to a "common function" like mobile Internet access.

This article is from the official account of Wechat: non-objective Laboratory (ID:zhinan617), author: lzh

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