Chapter 162: Communication Connects Everything, the World Will Never Lose Connection (Long Chapter)

Cao Shen never forgot that he wanted to do education.

Obviously, what he wanted to do was "online" education.

Then, the prerequisite was that there must be a network.

Even if the system had super compression capabilities, it would be useless without a network.

For education, Cao Shen could pay for the terminal equipment himself.

However, he really couldn't do the infrastructure such as the network.

First, there was not enough money, and second, there was no policy permission.

It was basically impossible to rely on operators to build it.

Operators are enterprises after all, and they pay attention to benefits and costs.

Asking them to build stations and networks in remote mountainous areas and maintain them for a long time, this kind of thing can be done for a few points of face-saving projects, but they will never do it to achieve full coverage and good use!

And after all, it is a market economy, and the country cannot do it according to the operators' heads in this regard.

The state can subsidize the construction of stations, but the large amount of maintenance costs in the later stage are far higher than the initial investment for remote areas.

Long-term subsidies are not realistic.

At present, high-quality education is a scarce resource, and rich people can spend money to get it.

The more remote and poorer the place is, the poorer the educational resources are.

This forms a vicious cycle. Poor people cannot receive good education, and they become poorer and poorer for generations!

Cao Shen is not doing education to add icing on the cake for the rich.

He wants everyone to have equal high-quality educational resources!

This matter cannot be pushed from the operator, so it can only be started from a higher level.

In the current "game", everyone is concerned about the higher-level strategy, and will not haggle with Cao Shen about the economic input-output ratio.

Ask him how to make money by laying the network in remote and poor areas.

They are concerned about things with more long-term value and a more international level.

Therefore, there is no need to raise the issue of education. First, education is sensitive, and second, Cao Shen himself is not fully prepared.

Just grab one thing and knock:

Internationalization, "encirclement"!

Establish a low-orbit satellite communication network to achieve seamless coverage of the global Internet...

Old man Yu and Mushroom Cloud looked at each other.

One of them leads the information industry, and the other covers aerospace.

Obviously, they also thought of the most famous case of low-orbit satellite communication network, "Iridium Project"!

"Iridium Project" is a plan proposed by Motorola, a US communications giant, in 1987 to use low-orbit satellite constellations to achieve global satellite mobile communications.

The system includes 77 low-Earth communication satellites, evenly and orderly distributed on 7 orbital planes 785km above the ground, forming a constellation, and forming a global connection network through microwave links.

The goal is to directly solve the technical problems of base station coverage at that time and let human communication enter the satellite era:

"Wireless communication can be achieved in any corner of the world where the sky can be seen."

Because the metal element iridium atom has 77 electrons, this plan is named "Iridium Project".

Later, in order to reduce the scale of investment, simplify the structure and enhance competitiveness with other low-Earth satellite communication systems, Motorola reduced the number of satellites to 66.

The orbital plane was reduced to 6 circular polar orbits, with 11 satellites on each polar orbit, and the orbital altitude was changed to 765km.

The satellite has a diameter of 1.2 meters, a height of 2.3 meters, a weight of 386.2 kilograms, and a lifespan of 5 to 8 years.

In May 1998, the satellite deployment mission was completed.

On November 1, the global communication service was officially launched.

However, the "Iridium Project" soon encountered competition from the rapidly rising cellular communication systems such as GSM in the world.

The "Iridium Project" was too advanced and the design was too idealistic.

At that time, satellite communication technology was restricted by equipment performance, and the system switching drop rate was as high as 15%, which seriously affected the call quality.

Moreover, in actual applications, the data transmission rate was only 2.4bk per second, which could not meet the needs well.

In addition, compared with system terminals such as GSM, the mobile phone terminals of satellite communications are difficult to miniaturize and have high prices, and the service charges are difficult to compete with GSM because of the high cost.

In the end, the "Iridium Project" suffered huge losses due to insufficient market penetration and quickly failed.

In March 1999, Iridium declared bankruptcy.

It was only five months away from the official launch of global services.

The entire Iridium system cost about $5 billion, but was eventually acquired by "Iridium Satellite LLC" for $25 million.

And on March 28, 2001, the new "Iridium Satellite" company resumed service.

This is really a "blood loss" lesson.

Mushroom Cloud first spoke to everyone:

"According to the different satellite orbit altitudes, communication satellites can be divided into low-orbit communication satellites LEO, medium-orbit communication satellites MEO and high-orbit geosynchronous communication satellites GEO.

LEO satellite orbit altitude is 500 km to 2000 km,

MEO satellite orbit altitude is 2000 to 36000 km,

GEO satellite orbit altitude is 36000 km.

The existing mature commercial communication satellites are mainly medium and high orbit satellites such as MEO and GEO.

Because of the high orbital position, a single satellite has a wide coverage area, and a small number of satellites can basically solve the problem of global coverage.

However, because of the high distance, medium and high orbit satellites are designed with strong penetration and large signal coverage area, so low-frequency bands are generally used.

The bandwidth of low-frequency bands is relatively small, and the amount of data that can be accommodated is small, which cannot meet the Internet access needs of massive users around the world.

Therefore, this kind of medium and high orbit satellite information is mainly used for information interconnection and TV broadcasting of specific users.

In terms of communication capability, it is equivalent to the 2G network of mobile communications, and a very small number can reach 3G, which only provides basic voice and low-capacity data services.

The application of high-orbit geosynchronous orbit satellites in simple communications, TV broadcasting, etc. has become mature.

But its disadvantages are also obvious, large size, heavy weight, large booster rockets, and long launch preparation time.

Moreover, this type of satellite has only one orbital plane, which can accommodate a limited number of satellites and cannot cover polar regions.

In addition, because it is far away from the earth, the communication delay is long, the beam coverage area is large, the spectrum utilization rate is low, the data capacity is small, the terminal transmission power is large, and it is not easy to achieve terminal miniaturization, etc.

As Xiao Cao said, using low-orbit satellites for global coverage is indeed more suitable for Internet applications than medium- and high-orbit satellites in terms of performance.

Low-orbit satellites, on the one hand, have a short transmission distance due to their low orbital altitude, so high-frequency bands can be used.

This is because, under a given transmission power, the higher the frequency, the smaller the transmission distance.

The frequency determines the size of the communication transmission bandwidth.

The upper limit of the amount of data transmitted per unit time increases with the increase of frequency.

Therefore, the orbits of high-throughput satellites are mainly concentrated in low orbits.

The Internet applications mentioned by Xiao Cao have high communication bandwidth requirements due to the large amount of data, and they do require the use of low-orbit high-throughput satellites to meet them.

Moreover, low-orbit satellites have short transmission delays and small path losses due to their short distances, and frequency reuse is more efficient.

On the other hand, this type of satellite is small in size and light in weight. Using current launch technology, it is already possible to launch two or even multiple satellites into orbit at the same time.

For users, receiving signals from such low-orbit satellites, because the transmission power is almost the same as that of ordinary land mobile communication terminals, the weight and size of the terminal are also small. "

The mushroom cloud is exactly what it means. China's Beidou satellite is a medium-to-high orbit satellite, and the cost is about 1 billion per satellite.

By 2019, the cost of small satellites in medium-to-low orbits has been able to reach 500,000 US dollars per satellite.

The main reason for the large number of traditional satellites is that the payloads are of various types and requirements, making it difficult to achieve mass production.

The small satellites in the later period of the original world have been standardized and modularized as much as possible.

In terms of the manufacturing process, the "assembly line" method of aircraft manufacturing was borrowed.

Relying on this method, OneWeb's "satellite factory" has achieved weekly production of The ability to produce 16 satellites.

"Multiple satellites in one rocket" means using a carrier rocket to send multiple satellites into orbit at the same time, greatly improving the efficiency of commercial satellite launches.

This technology is already relatively mature in the original world.

In January 2020, SpaceX launched 60 satellites in one rocket. And the company's next-generation heavy rocket plans to achieve 400 launches in one rocket.

China has also mastered a number of core technologies such as separation and release, and multiple satellites into orbit. In 2015, the Long March 6 rocket was successfully launched, with 20 satellites in one rocket.

In addition, rocket recyclable technology can further reduce the cost of satellite networking.

Take SpaceX as an example. The first launch using a brand new rocket was quoted at $61.98 million, and the price was $29.9 million for the 10th launch.

If we compromise, based on the price quoted for the fourth launch, the launch cost of a satellite is about $600,000.

Of course, the launch price of a satellite is based on weight, about $5,000 per kilogram. If the satellite can be made lighter, the launch cost in the future can be further reduced.

China has also mastered some rocket recovery technology. The Long March 8 launched by China Aerospace Science and Technology Corporation in 2020 used the remaining fuel to land vertically in the first stage and can be reused.

Cao Shen looked at the mushroom cloud and nodded:

"The most famous case of low-orbit satellite networking is the 'Iridium Project'.

Although the original Iridium Project failed, the Iridium system opened the precedent for personal satellite mobile communications.

It also verified the possibility of low-Earth orbit constellations as mobile communications.

Thirteen years have passed. With the reduction of launch costs and the advancement of communication technology, high-bandwidth, low-latency satellite communications based on low orbits have become possible.

Low-orbit satellites require more satellites because each satellite covers a relatively small area.

This makes ground control and system maintenance more complicated.

For this multi-satellite system, the biggest issues affecting communication are beam switching and inter-satellite switching.

Low-orbit satellites move at high speed relative to the earth, so that the terminal needs to frequently switch to other beams or satellites during communication to continue the call.

Taking the initial Iridium system at that time as an example, its minimum switching time interval was 10.3 seconds and the average switching time interval was 277.7 seconds.

A series of signaling operations are required to achieve switching, and frequent switching increases the signaling load of the system.

This leads to the fact that the more frequent the switching, the greater the probability of switching failure. In the end, the Iridium system's initial switching success rate was only 85%, which is far from the switching drop rate of the land mobile communication system.

A closer analysis of the main reason for the switching drop is that the bandwidth resources of the low-orbit satellite communication system at that time could not meet the minimum bandwidth requirements for switching calls.

But thirteen years have passed, and during this period, communication technology and microelectronics technology have developed rapidly.

The signal processing capabilities and communication bandwidth of the communication system are also constantly improving.

Judging from the use of low-orbit satellite communication systems such as "Iridium II" and "Globalstar" that are still in operation, these early technical problems have been effectively solved.

Therefore, I think it is completely feasible to build a low-orbit satellite communication network with current technology. "

Mushroom Cloud also nodded slowly:

"Yes, if it is just from a technical point of view, thirteen years have passed, and it is indeed more feasible.

However, the failure of the Iridium plan at the beginning was not only due to technical reasons, but also commercial reasons. "

As he said, Mushroom Cloud glanced at Old Man Yu:

"Now, let's assume that there are no technical problems.

According to what you said, Xiao Cao, there are 3 billion people who have not yet accessed the Internet, which is considered a "sinking" market.

However, if the low-orbit satellite network is successfully established, it will cover the world.

Of course, we also hope that we can have a higher utilization rate.

But the technology of the ground communication network is already very mature, and users have already developed deep usage habits.

It is very unrealistic to use satellite communication to replace ground communication. "

What this means is that if we spend a lot of effort to build a network, it is just that the 3 billion remote and poor people are not hungry enough.

Cao Shen said:

"For low-orbit satellite communication, if the Ka band of 27GHz to 40GHz is used, the satellite communication bandwidth can be increased from 100Mbps to Gbps.

This bandwidth size has exceeded 4G and can be compared with the planned 5G.

Despite this, the ground network is always based on 4G or the future 5G.

Our country plans to build about 5 million 4G base stations.

A high-throughput communication satellite is assumed to have the same performance as a 4G base station.

Then to achieve the same user experience as 4G, there must be 5 million satellites.

This is obviously unrealistic. "

Of course, this is under normal circumstances.

In fact, Cao Shen has a system, and I can use it as long as you have network coverage!

Cao Shen continued:

"So, I think the satellite network will be a supplement to the ground network in the future.

In addition to covering the 3 billion people, the more critical scenario is to use it in the "Internet of Things" service.

Satellite communication is not restricted by region and has a wider coverage capability.

It has high stability, strong resistance to physical attacks and natural disasters, and is almost unaffected by local natural disasters and emergencies.

In addition, in terms of cost, the marginal cost is extremely low. It does not rely on ground infrastructure and directly realizes sky relay transmission.

This is unlike ground operators, who must lay new base station groups for each area they open up.

These advantages are more suitable for the Internet of Things, which has higher reliability requirements and wider geographical distribution.

For example, ocean-going ships, deserts, wilderness, and airplanes are scenes that ground communications cannot cover.

And many scenes will have fewer people but more machines in the future.

For example, energy construction scenarios such as wind power, solar power generation, and oil extraction.

For example, outdoor power grid line monitoring, forest monitoring, fire warning, etc.

Moreover, the number of connections in the Internet of Things in the future will far exceed the number of human network connections.

I predict that in ten years, the number of connections in the Internet of Things will reach 70 billion.

The resulting communication demand is strong.

Just like the autonomous driving we mentioned today, this is an example of the Internet of Things.

In the future, the connection between people and machines, and the connection between machines and machines will occupy more network resources.

Once our country's low-orbit satellite network is built, there will be an opportunity to build a large-scale Internet of Things that integrates the world.

At this time, traditional ground communications will become a supplement to the entire network. "

Seeing the mushroom cloud start to blush with excitement, Cao Shen did not intend to stop there, and continued:

"Besides, you also know that orbits and spectrum are prerequisites for the normal operation of communication satellites.

Because a single low-orbit satellite has a small coverage range, the number must be increased to achieve global coverage.

This will make the already limited orbital and spectrum resources even more tense, and countries around the world will definitely have fierce competition on this issue in the future.

The ITU, the United Nations agency in charge of communications technology, chooses the first-come, first-served principle for the allocation and management of global wireless spectrum and satellite orbit resources.

Moreover, the occupation time is time-limited. If the satellite is not launched on time, the original orbit and spectrum will become invalid.

Therefore, the low-orbit satellite network will sooner or later become an important international competition field. After all, in addition to business, this is also a competition for the strategic value of space orbit.

We, the East, suggest that we make arrangements as soon as possible.

After all, we still have advantages in aerospace technology..."

This is not Cao Shen's sensationalism. In the original world, the competition for low-altitude orbits is very fierce.

As of January 9, 2019, there are 2,062 satellites in orbit around the world.

In the low-orbit communication satellite program announced by foreign countries at the beginning of 2019, the total number of satellites is about 23,892.

Even SpaceX applied to the ITU again in October 2019. In total, this company applied for 42,000 orbital positions.

The orbital heights of these low-orbit satellites are mainly concentrated between 1,000 and 1,500 kilometers, and the frequency bands are mainly concentrated in the Ka, Ku and V bands.

The orbital height range is very limited, the frequency bands are highly concentrated, and the competition is very fierce.

First come, first served, and then there is no later!

In addition, industry giants such as Oneweb, SpaceX, Amazon, and Internet companies such as Google and Facebook have joined the low-orbit communication satellite competition camp and launched their own low-orbit communication satellite construction plans.

In early 2010, Google jointly launched the "O3b Plan" with HSBC and European cable TV operator Liberty Global.

O3b originally means "Other 3 billion", which refers to the 3 billion people who still cannot access the Internet. This project later established the famous OneWeb, which is also the biggest competitor of SpaceX.

In 2015, Google invested another $1 billion in SpaceX, one of its purposes was to build a space Internet.

In the same year, SpaceX launched the Starlink project, planning to launch about 42,000 satellites to form a low-orbit satellite communication system.

In 2017, Facebook established a subsidiary PointView Tech LLC and invested millions of dollars in the development of experimental satellites. The satellite is called Athena, which will transmit data 10 times faster than the Starlink satellite network.

In April 2019, Amazon launched the Kuiper project, planning to launch 3,236 low-orbit communication satellites to provide fast and low-latency Internet access services worldwide.

In addition to Internet giants, companies including Boeing, Airbus, and Samsung are actively developing low-orbit communication satellite systems.

For low-orbit satellite networking, China's Aerospace Science and Technology Corporation and China Aerospace Science and Industry Corporation have proposed two constellation plans, "Hongyan" and "Hongyun".

300 and 156 low-orbit communication satellites will be launched respectively to form a space communication network, and the two systems are scheduled to be completed in 2023.

At present, the first experimental satellites of the two systems have been successfully tested at the end of 2018.

The initial investment in the networking construction of the "Hongyan" and "Hongyun" systems is estimated to be about 30 billion yuan. my country will also enter the era of low-orbit satellite communications.

Currently, SpaceX's satellites in orbit form the constellation "Starlink", and the theoretical bandwidth can reach more than 1 to 2Gbps.

Provide users with a maximum downlink speed of 60Mbps, and the uplink speed fluctuates greatly, and can basically guarantee around 10Mbps.

China Unicom's 4G network standards are TD-LTE and FDD-LTE.

The theoretical downlink speed of TD-LTE is 100Mbps, and the theoretical uplink speed is 50Mbps.

The actual downlink speed of China Unicom 4G is about 50Mbps, and the uplink speed is 10 to 20Mbps.

Therefore, users of "Starlink" can already smoothly watch ultra-high-definition videos and play online battle games.

Mushroom Cloud held Chengquan's hand and hammered the table hard:

"Cao Shen, you are right!

Deploying a low-orbit satellite network is far more than a commercial significance, but also a strategic value of orbital space.

In addition, the Internet of Things will be a network with higher data value than the Internet.

The Internet is an information network, which does have a lot of content and interactive information between people.

But the Internet of Things is data between machines and people, machines and machines, and machines and controls.

It also constitutes the context of the operation of the entire world.

The value of the Internet of Things is very high, and the data of the global Internet of Things is very critical!"

The old man Yu, who is in charge of the information industry, also sighed and said:

"To use ground communications, establish base stations in other countries and operate them, and obtain data from the Internet of Things in other countries, it cannot be said to be completely impossible, but it is very, very difficult.

The Internet actually has boundaries and national boundaries.

But, satellite networks can really We are realizing globalization and realizing global data interaction and flow.

Cao Shen, the suggestion you put forward today is no longer a business issue.

This is a national strategy!

On behalf of the country, I thank you for giving us such important and valuable ideas through your understanding of technology, products, markets, and competitive landscape.

It's really great! ”

The old man supported himself on the chair and slowly stood up, looking at everyone, and then said to Cao Shen solemnly:

"Cao Shen, I thank you too.

At the same time, I solemnly promise you that our Dongguo will do its best to build a low-orbit satellite communication system that can meet the needs as soon as possible!"

He stretched out his hands and held Cao Shen's hands tightly:

"This is a promise from a great country.

Communication connects everything, and the world will never lose connection!"

The scorching temperature and trembling strength came from his hands, and Cao Shen saw the light in the old man's eyes...

The most important thing for a country should be like this!

——————

“Communicate and connect everything, the world will never lose connection”,

From the low-orbit satellite communication network that my country is building - the “Hongyan” constellation.

From the stars, the Hongyan sends messages.

This chapter contains a lot of popular science, the purpose is to let everyone understand what the world is doing, what our country is doing, and what we can do in the future.