I've been waiting for 10 years for the technology that allows me to surf the Internet on airplanes. Where does it come from?

In the past, when we were on an airplane, the flight attendants would tell us that we needed to turn off our phones. This rule has changed recently. According to the statement of the Civil Aviation Administration of China on portable electronic devices (PEDs) on airplanes, starting from 00:00 on January 18, 2018, Chinese users no longer need to turn off their phones when on an airplane.

After much waiting, the era of mobile phone communications on airplanes has finally arrived, but do you know the technology behind it? Let me tell you slowly.

Why did some airplanes have Internet access before?

Answer: Aircraft Internet access benefits from two modes: satellite mode and ground base station mode (ATG).

First, let's understand why you can't use your mobile phone on an airplane. The reason is that the signals emitted by mobile phones and other electronic devices may interfere with the normal signal transmission of the aircraft and cause the aircraft to be in an incorrect operating state, seriously affecting flight safety. In layman's terms, the ground base station transmits signals to the aircraft, which may be affected by the signals transmitted by mobile phones.

Will it affect the ground base station signal? Then why not just use my mobile phone without transmitting the signal through the ground base station? There will be no interference if I use other methods. Therefore, the satellite mode, one of the two major modes of airplane Internet access, was developed.

Mobile phones do not use ground base stations, but directly "communicate" with satellites to access the Internet. You may ask, will the signals from satellites affect airplanes?

The answer is no. The band currently used for airplane Internet access is the Ku band in the frequency range of 12.24-18GHz, while the operating frequency of current mobile phone systems and aircraft during flight is between 800 and 1800MHz, so it is staggered with the band used by satellite mode and will not be affected.

Many companies are using the satellite model, such as Iridium, Inmarsat, and some commercial Ku-band satellites (Panasonic's solution is more mature).

Normally, aircraft in satellite mode will have a relatively raised "bulge" on the top, which is the "cat" used specifically to receive satellite signals.

The advantage of satellite mode is that it covers a wider area, but there are also some problems. That is, when the fuselage shakes or makes some maneuvers, the signal will be greatly affected due to the antenna posture problem, and the network speed will become unstable, commonly known as "stuck".

Aircraft that use satellite mode to access the Internet usually connect to a specific "Wi-Fi" to access the Internet. Although the transmission frequency band is different, just in case, it still needs to be used when the aircraft is flying above 3000m or parked on the ground.

Having discussed the first of the two major modes of airplane Internet access, let’s look at the second one, which is the ground base station mode (ATG).

The ground base station mode (ATG) stands for Air to Ground, a type of low-altitude signal transmission. It requires the establishment of ground base stations along the flight route or specific airspace to provide coverage to high altitudes, that is, using these ground base stations to directly transmit information with aircraft.

Does it sound confusing and incomprehensible?

To put it simply, it means building a base station for the aircraft, which is specifically used for passengers to access the Internet. This creates some limitations - when deploying ground base stations, these base stations are difficult to deploy across countries. Therefore, this communication method is not suitable for transoceanic (international routes) use and is more suitable for countries with larger land areas.

Currently, 1,500 flights of nine airlines in the United States have used this communication method to achieve a comprehensive in-flight Internet experience. The disadvantage is that the signal coverage is not wide enough. After all, the area affected by the ground base station signal is limited, not as wide as the radiation range of the satellite mode.

Why is it that although these two modes have already been available, Internet access in airplanes is not yet popular?

A: To put it bluntly, Internet access in airplanes costs money. The usage fee is expensive and the cost is also high. Not only that, it was also stuck due to the immature technology. It is also expensive. Which airline dares to use it?

This is indeed the case. The ground base station mode (ATG) requires the ground base station to transmit to the air, and the aircraft uses an antenna installed on the belly to receive it.

Generally, an omnidirectional antenna is used (characterized by a smaller antenna that does not require a servo). In addition, airborne equipment, a dedicated server, a Wi-Fi hotspot device, etc. are required. Although the total cost is cheaper than a satellite solution, it still costs about US$300,000.

The network speed is also very impressive. The Ku band can achieve a downlink rate of 5Mbps and an uplink rate of 1Mbps. As mentioned above, the actual usage will become stuck when the body shakes or makes some maneuvers. The actual usage experience before was not optimistic.

Why can't I request Internet access even though my phone is in airplane mode?

If satellite mode and ground base station mode (ATG) are the two major airplane Internet access modes that are improved based on the signal source, then flight mode is the mode that is improved for mobile phones.

However, for many years, the airplane mode was not allowed on airplanes. In the past, the so-called airplane mode was mostly just a statement made by mobile phone manufacturers to justify themselves, and it had not been tested and accepted by the aviation department for safety. Therefore, before this, the airplane mode of mobile phones was not recognized by the aviation department and airlines.

One thing needs to be understood, from a safety perspective, airplanes, a means of transportation that requires extremely high safety, must eliminate unsafe factors as much as possible, rather than ignoring unsafe areas as much as possible.

Of course, the flight mode that has not been certified for safety will be banned. This is why, even if a mobile phone has flight mode, it is still forbidden to use the mobile phone on the plane.

What are the advantages of ChinaSat-16?

First of all, this satellite has a 20G bandwidth, mainly covering the eastern and eastern coastal areas of my country. A new satellite with an 18G bandwidth to be launched next year will cover the western region of my country, while China Unicom will expand its air satellite communication services to a larger area.

On January 9, 2018, during French President Emmanuel Macron's visit to China, China Unicom and Eutelsat signed a memorandum of understanding on cooperation at the Great Hall of the People, reaching a strategic consensus on jointly developing satellite communication business in the "Belt and Road" region.

According to the agreement, in the initial stage of this cooperation, the EUTELSAT 172B satellite will be used to enhance China Unicom's satellite communication service capabilities from the west coast of North America to Asia and Oceania. Through E10A, aviation airborne communication services can be extended to the European continent. In the future, more resources will be considered to be deployed to provide satellite communication services on a global scale.

To this end, China Unicom also bought out 40% of Eutelsat’s resources for their entire 15-year life cycle.

How much does it cost to surf the Internet on an airplane? Is it expensive?

One thing worth mentioning is that although Chinese users can use their mobile phones to access the Internet while on airplanes from 00:00 on January 18, 2018, they still cannot make phone calls. Although satellite calls can be made on airplanes, due to the high cost, it is not yet widely available.

Some experts in the industry pointed out that in order to solve the problem of low-cost phone calls on airplanes at the technical level, it is necessary to increase the onboard communication bandwidth and transmission rate by more than 10-100 times.

It is necessary to integrate satellite mode, ATG base station or future 5G communication network, and optimize the in-flight voice transmission technology and upgrade the corresponding mobile phone chip algorithm according to the characteristics of voice services. In general, there is still a long way to go to realize making calls on airplanes.

After saying so much nonsense, let's answer the key point: How much does it cost to surf the Internet in an airplane?

Regarding the question of whether in-flight Internet access is charged, I have sorted out the issues that passengers are concerned about, and found that China Eastern Airlines, China Southern Airlines, Air China, and Hainan Airlines currently do not charge for in-flight Wi-Fi. Lin Zhijie, a senior civil aviation expert, said that the cost of in-flight Internet access is relatively high at present, and if airlines want to attract passengers to buy tickets, there is no question of charging passengers, or they may charge a symbolic fee.

"But if airlines regard it as a profitable project, they will charge passengers directly or charge advertisers and other channels." He described that, for now, some domestic airlines may charge passengers directly for traffic fees in the future.

I think that in-flight Wi-Fi will not cost too much after it becomes popular in the future. First of all, frequent flyers are already accustomed to not using their phones on planes. In addition, airplanes are one of the fastest means of transportation currently available. On planes with shorter journeys, most passengers can tolerate not using the Internet.

Therefore, if they want to earn profits by keeping the fees high, they are likely to end up like a snake swallowing an elephant. Of course, it is not ruled out that they will adopt a profit model of boiling a frog in warm water, such as "major takeout" and "shared bicycles", that is, there are many discounts at the beginning, and the price will be raised slowly.

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In general, the successful launch of ChinaSat-16 heralds the beginning of global in-flight Internet access, creates benefits for China, East Asia, South Asia and other regions covered by the signal, and provides convenience for airplane passengers.

But I don't seem to be excited. As a thrifty user like me who would rather take the train than the plane, I still hope that air ticket prices can be reduced. After all, at present, flying is considered a relatively luxurious "activity".