Satellite Communication: Huawei Mate 50 vs. iPhone 14

Satellite Communication: Huawei Mate 50 vs. iPhone 14.

Satellite communication is particularly hot recently, but it is indeed the first time that satellite communication is used in consumer-grade smartphones.

The 2022-released Huawei Mate50 and iPhone 14 also support satellite communication, and its main purpose is to give users in distress in areas without signal an extra way to call for help.

Satellite Communication: Huawei Mate 50 vs. iPhone 14.

Satellite Communication: Huawei Mate 50 vs. iPhone 14

Companies participating in the satellite communication market are not limited to Huawei and Apple.

Geely, Musk, T-mobile, Qualcomm and other names also appear in different positions in the industry chain of this market.

In addition, many high-tech companies seem to be exploring other commercial uses of low-orbit satellites, and “gold nuggets” are still being launched in different fields.

Elon Musk will cooperate with T-Mobile to use Starlink satellites to provide connection services for T-Mobile mobile phones from 2023.

As a mainstream provider of mobile phone SoC, Qualcomm is also closely watching this opportunity.

As early as February 2021, Qualcomm announced that it will support the n53 frequency band on the future X65 baseband chip, which is owned by Globalstar.

The mobile phone SoC giant MediaTek and Rohde & Schwarz cooperated to simulate the data transmission test to the 5G base station (gNB) on the low-orbit (LEO) satellite channel, and took the lead in demonstrating the satellite communication support capability based on 5G smartphone hardware.

According to the official statement, this test is based on the functions and procedures defined in the 3GPP R17 5G specification, using MediaTek’s mobile communication test chip with 5G NR NTN satellite network functions, and Rohde & Schwarz’s low-orbit satellite channel simulator and test base station to simulate in the laboratory a low-orbit (LEO) satellite at an altitude of 600 kilometers and moving at speeds of up to 27,000 kilometers per hour.

In this experiment, MediaTek demonstrated the feasibility of using 5G NTN technology for satellite communications, using the same components as smartphones.

Many netizens will ask, didn’t satellite phones appear decades ago? For example, the Iridium and Maritime satellite phone series.

In recent years, China has also had developed Tiantong satellite phone system.

Most people also know that satellite phones are purpose-built, proprietary, and expensive.

In the early years, the price of satellite phones was generally more than 2000 U.S. dollar, and the cheapest one is currently around US$1000.

Coupled with the high degree of ground network coverage in China, satellite phones are only useful in very few extreme cases, so few people will buy them specifically, which leads to the general inability of people to enjoy satellite communication services.

Conversely, it has also caused the satellite communication industry to stay away from the consumer market, and it is difficult to form a large-scale situation.

Why can’t commonly used consumer smart phones be compatible with satellite communication functions?

The main reason is that mobile phones and satellite phones are very different:

First, the traditional satellite communication protocol and communication frequency band are different from the ground mobile communication network, and there are differences in baseband processing, radio frequency circuit and antenna design;

Second, if a mobile phone wants to support satellite communications , it first needs hardware support.

The iPhone 14 may use a customized Qualcomm X60 baseband chip that supports satellite communications .

Moreover, this feature of Apple has an exclusivity period.

If other smart phone brands also want to add the function of supporting satellite communication, they may use the X65 baseband chip.

Third, since the distance between mobile communication satellites and the ground is between several hundred kilometers (LEO orbit) and 27,000 kilometers (GEO orbit), the maximum transmission power of traditional satellite phones needs to be above 2 watts.

For mobile phones, according to the standards stipulated by the governments of most countries, the maximum transmission power in FDD mode cannot exceed 23dbm, that is, 200 milliwatts, and the maximum transmission power in TDD mode cannot exceed 26dbm, that is, 400 milliwatts.

In the past, due to technical limitations , The communication industry has never thought of allowing mobile phones with such a small transmission power to communicate directly with satellites.

In recent years, due to the advancement of technologies such as antennas, radio frequency circuits, and signal processing, direct communication between mobile phones and satellites has become possible, so this function has become a hot topic in the current communication industry.

Satellite communication can be divided into narrowband communication and broadband communication. The narrowband communication used by Huawei is basically based on text, while the broadband can be used for video and voice communication. In fact, the Beidou satellite used by Huawei was initially based on positioning.

Before the launch of the iPhone 14, many experts predicted that Apple’s satellite communications might use broadband communications.

However, although Apple’s satellite communication can be two-way, unlike Huawei’s one-way satellite communication, Apple’s satellite communication still only uses text.

Satellite Communication: Huawei Mate 50 vs. iPhone 14. Comparison of satellite communication functions between mate50 and iPhone14

Satellite Communication: Huawei Mate 50 vs. iPhone 14

How to use the function of Mate50 to send text messages through Beidou satellite?

1. To use this function through the Changlian APP, there is no need to apply for a special Beidou communication card;

2. During the trial period, a free quota of 30 pieces per month is provided, beyond which packages can be purchased;

According to the information on the function page, if you open the Beidou satellite service account for the first time and complete the registration, you can experience 30 free quotas per month, and clear and recharge new quotas at 24:00 on the last day of the month.

For example, if the user opens the Beidou satellite news service account and completes the registration on January 15, 2022, then he will have 30 free sending quotas before 24:00 on January 31, 2022. If the user sends a total of 8 satellite messages in January, there are still 22 free quotas left in this month, but these 22 free quotas will be automatically cleared at 24:00 on January 31, and the system will automatically recharge the new 30 free amount.

Among them, it should be noted that: when there are 3 free quotas left in the current month, the system will send a reminder message; after the free quota during the trial period is used up, it will not be able to continue sending; the free quota during the trial period cannot be advanced across months; the trial period ends After that, you need to purchase a package for normal use.

3. Can only send text messages, but not receive;

4. Before sending text messages, the mobile phone needs to align itself with the Beidou satellite according to the prompts of the APP. Only when it is aligned with a certain Beidou satellite can it be sent normally;

5. You can choose one of dozens of preset text messages to send. These short messages include location information. Users can also manually enter a message with more than a dozen characters in addition to the preset information.

The number of words depends on the number of recipients And change (up to four people can choose to send at the same time), the more recipients, the fewer words the user can manually input; Beidou satellite will forward the received SMS to the operator’s satellite ground station, and then through the operator The network sends to the recipient. Regardless of whether the recipient uses a Huawei mobile phone or APP, it can be received normally;

6. It needs to be used in an open and unsheltered environment. However, according to Li Xiaolong, vice president of Huawei’s mobile phone product line, according to his actual measurement, the Mate50 series can be used to send messages to Beidou satellites on the ground in cities and in virgin forests, but not on airplanes.

The Beidou satellite will forward the received SMS to the operator’s satellite ground station, and then send it to the recipient through the operator’s network. Regardless of whether the recipient uses a Huawei mobile phone or APP, they can receive it normally.

Apple iPhone14 satellite communication function use;

1. This function will be integrated into the messaging application as a third protocol, alongside ordinary SMS and iMessage, and will be displayed as a gray message box when in use, and the length of the message will be limited.

2. The sent SMS will be automatically pushed to the mobile phone of the emergency contact, even if the other party has turned on Do Not Disturb.

3. Support receiving responses from emergency agencies.

4. When emergency services are contacted, the function can send the user’s location and medical ID, and can also notify the user’s emergency contacts. Among them, the medical ID is a virtual information card in the health function, including the user’s medical history, age, medication, height and weight and other information.

5. The satellite communication service will be launched in November, and the iPhone 14 series models can use the satellite SOS emergency contact function for free for two years.

6. This function only supports the United States and Canada.

7. At present, Apple has created a mechanism that requires users to be outdoors and walk in a certain direction to help the iPhone connect to the satellite. Connecting to the network isn’t always instant either, with testing of the feature showing that it can sometimes take up to a minute before it starts working.

As for the use scenarios of satellite communication, it is actually used for emergency communication in suburban and mountainous areas. In cities, areas where cellular data is not available, such as garages and elevators, cannot receive satellite signals.

According to the different orbits of communication satellites, satellite communication (system) can be divided into:

Low-orbit (LEO) satellite communication :

LEO satellites are small and operate on orbits 500-2000km above the ground, with transmission delay (Starlink two-way communication delay is 50-70ms), coverage, link loss, and low power consumption.

A typical system is the second-generation Iridium system of Iridium Communications Corporation (IRDM) of the United States.

Medium orbit (MEO) satellite communication :

MEO satellites operate on orbits 2000-20000km above the ground, and their transmission delay (MEO satellite system O3b two-way communication delay is about 300ms), coverage, link loss, and power consumption are greater than those of LEO But smaller than GEO.

A typical system is the International Maritime Satellite System of the British company Inmarsat.

High-orbit (GEO) synchronous satellite communication :

GEO satellites operate in a geosynchronous geostationary orbit 35,800km above the ground. The traditional GEO communication system technology is the most mature, but there is a significant delay in real-time communication due to the long propagation delay (two-way communication delay of more than 500ms) and large link loss.

The satellite communication system consists of three parts: the space segment, the ground segment and the user segment:

Space segment :

with communication satellites as the main body, the relay on the satellite is the main payload of the communication satellite and the most important functional component of the space segment of the satellite communication system. It is used to receive and forward signals from the satellite communication earth station to realize the Communication between stations or between an earth station and a spacecraft.

Ground segment :

ncluding all facilities that support mobile phones, TV viewers, and ground users of network operators to access satellite transponders and realize communication between users.

The gateway station is the core equipment of the ground segment. The ground segment of the satellite communication system also includes the ground satellite control center (SCC, Satellite Control Center) and the tracking, measurement and control and command station (TT&C, Tracking, Telemetry and Command station).

SCC and TT&C are mainly responsible for the tracking and positioning of the satellite launch phase , issue action commands such as orbit change and solar panel deployment, as well as orbit monitoring and correction, interference and abnormal problem monitoring and detection during the satellite’s in-orbit operation.

User segment :

It mainly consists of various end-user devices, including VSAT small stations, handheld terminals, and mobile terminals mounted on vehicles, ships, and airplanes, as well as various application software and services based on satellite communications.

As a form of radio communication, satellite communication also relies on radio waves of different frequency bands for signal relay and transmission.

In the application of ground radar system, radio waves are divided into frequency bands such as VHF, UHF, L, S, C, X, Ku, Ka and EHF in IEEE standards.

In practical applications, only a small part of the above-mentioned frequency bands is allocated to radar applications, and most of the frequency bands are allocated to space radio applications by the World Radiocommunication Conference of the International Telecommunications Union (ITU, International Telecommunication Union).

The radar frequency band corresponds to the space radio frequency band The relationship is shown in Table 1 and Table 2.

In order to ensure that the scarce resource of radio frequency can be used reasonably and effectively, ITU divides the world into three frequency regions.

Radio frequency bands are roughly divided according to different business types:

C frequency band (4GHz~8GHz), Ku frequency band (12GHz~18GHz) and Ka frequency band (26.5GHz~40GHz) are currently the most widely used frequency bands in satellite communication systems, C frequency band The Ku and Ku frequency bands are mainly used for satellite broadcasting and satellite fixed communication services, with limited bandwidth and early utilization, and the current use of spectrum has tended to be saturated;

the Ka frequency band is mainly used for high-throughput satellites, providing mobile broadband communications at sea, in the air and on land .

Q/V frequency band will be the focus of competition in the field of satellite communication in the future.

Currently, ITU is formulating spectrum sharing rules for using Q/V frequency band in NGSO satellite communication to ensure that NGSO system, GSO system and other NGSO systems can coexist.

It is worth noting that The first star of the 5G constellation successfully launched by Yinhe Aerospace on January 16, 2020 is the world’s first NGSO communication satellite in the Q/V frequency band.

Features and Advantages of LEO Satellite Communication System

Compared with the traditional geostationary satellite communication system, the most notable feature of the low-orbit satellite communication system is the difference in the height of the satellite’s working orbit and the complexity of the system, which brings differences in single-satellite technology, scale, and cost, and ultimately affects System construction and operating costs and system reliability.

The technical characteristics of the low-orbit satellite communication constellation will also affect the communication quality of the system, and also put forward different technical and performance requirements for the ground terminal equipment. In addition, the low-orbit satellite communication system can adopt cellular communication, spot beam, multiple access, frequency multiplexing and other technologies, and the communication has the advantages of global coverage and low delay, and can support real-time or near-real-time online games, video calls, etc. Data transmission, after being integrated with the ground communication backbone network, may give rise to new application scenarios.

From a technical point of view, the main difference between the low-orbit satellite communication system and the high-orbit satellite communication system lies in the height of the satellite orbit and the communication capability of a single satellite. The specific technical differences are as follows: aspect:

Transmission delay :

The orbital altitude of high-orbit communication satellites is 35,786 kilometers, and the communication transmission delay of each hop (terminal-satellite-terminal) is about 270 milliseconds. At present, most of the satellites of the mainstream low-orbit constellations are located in the sky above 1000-1400 kilometers, and their communication transmission delay is about 7 milliseconds per hop. Considering the impact of delay in other aspects, it can also be within 50 milliseconds. Latency is comparable.

Transmission loss :

The orbital height of the low-orbit constellation broadband satellite is about 1/30 of the orbital height of the geostationary satellite, and the free space loss of the low-orbit satellite signal is 29.5dB less than that of the geostationary satellite. The cornerstone of data transfer.

Sub-satellite point movement speed :

The motion speed of geostationary orbit satellites is the same as the rotation speed of the earth, and the satellites circle the earth at 24 o’clock, which is relatively stationary to the ground; the motion speed of low-orbit satellites is about 7.5 km/s, and the satellites circle the earth in 85~115 minutes , moving at high speed relative to the earth’s surface, which brings technical problems such as Doppler frequency shift, ground terminal antenna pointing tracking, and beam switching.

Beam coverage :

High-orbit communication satellites have a high orbital height and a large field of view to the ground. The deployment of three satellites can achieve global coverage beyond the North and South Poles; low-orbit communication satellites have a low orbital Multi-star networking can achieve global coverage and avoid communication interference caused by occlusion, but it will also bring higher requirements for the communication system due to the increased difficulty of frequency reuse.

Satellite capacity :

The single satellite of the low-orbit satellite communication system is small in size, light in weight, and weak in communication capability, but the communication capacity of the entire system is relatively high. For example, the design quality of a single satellite in the OneWeb constellation system is only 125kg, and the capacity of a single satellite is about 10Gb/s, and the entire constellation will have a capacity of 7Tb/s. The Viasat-3 satellite system consists of three satellites, the design weight of a single satellite is about 6400kg, the capacity of a single satellite is about 1Tb/s, and the whole system has a capacity of 3Tb/s.

System reliability :

The reliability of the low-orbit satellite communication system is higher. First, the number of low-orbit constellation satellites is huge, and they are distributed in multiple orbital planes. The damage of any one or a few satellites will not have a major impact on the system; There are multiple backup satellites that can replace damaged satellites at any time; third, low-orbit satellites are low in cost, short in development cycle, small in size, light in weight, and low in orbital altitude, making it easy to launch emergency network repairs.

The construction cost of satellite communication system includes the main parts such as satellite development cost, rocket and launch cost, ground station construction cost and user terminal price.

The cost of various aspects of the low-orbit satellite communication system and the traditional high-orbit satellite communication system is also quite different:

Satellite manufacturing cost:

Low-orbit communication satellites usually use micro-satellite platforms. The technical difficulty and satellite scale are much lower than traditional high-orbit communication satellites, and the development cost of a single satellite is significantly reduced.

Adopting an assembly line and mass production method similar to high-end industrial products such as automobiles and airplanes is a necessary requirement for the construction of low-orbit satellite communication systems, and it is also conducive to the reduction of single-satellite manufacturing costs.

The single-star development cost of the OneWeb system is about 600,000 U.S. dollars, while the single-star cost of the high-orbit ViaSat system is about 360 million U.S. dollars, and the entire system cost is about 1.08 billion U.S. dollars. One hundred million U.S. dollars.

Rockets and launch costs:

There are a large number of satellites in the low-orbit satellite system, and multiple launches are required to put all the satellites into orbit.

Therefore, launch costs account for a large proportion of system construction. Oneweb has signed contracts with Arianespace for 21 launches worth more than $1 billion.

The ViaSat-2 satellite launch and insurance costs are 170 million US dollars, the ViaSat-3 satellite launch and insurance costs are basically the same as the ViaSat-2 satellites, and the three satellites need a total of 510 million US dollars.

Ground station construction cost:

The ground station consists of three types of earth stations: measurement and control stations, gateway stations and control centers.

Oneweb satellite measurement and control stations are located in high-latitude areas, with antenna diameters of 2.4m or above;

55 to 75 satellite gateway stations will be deployed around the world, and each gateway station will be equipped with more than ten pairs of antennas with a diameter of more than 2.4m;

the system will be deployed in the United States China and the UK set up at least two independent control centers.

The capacity of Viasat-1 system is only 150Gb/s, and 21 gateway stations are set up.

The gateway station is equipped with a 7.3m Ka-band antenna.

It can be calculated that the number of gateway stations of Viasat-3 star system with a capacity of 3Tb/s will reach several Hundreds, and at least 3 measurement and control stations correspond to 3 different satellites.

For the low-orbit satellite communication system, the construction of the space segment and the ground station can find a cost control solution within the existing technical framework;

considering the broad application prospects, the operator can also accept a slightly higher one-time capital expenditure. The cost of the user terminal is the key to determine whether the satellite system can achieve commercial success.

Currently, the price of a fixed terminal for a high-orbit communication satellite is about 3,000 US dollars, and the price of a portable terminal is about 28,000 US dollars.

The antenna of the ground terminal of the low-orbit satellite communication system needs to track the satellite signal and ensure that the signal is not interrupted when the satellite is switched, which increases the technical difficulty of the terminal antenna.

It is difficult for users to accept terminal products worth tens of thousands or even hundreds of thousands of dollars.

Higher requirements are put forward for low-cost dual parabolic antenna or phased array antenna technology.