Over the past 80 years, the telecommunications industry has experienced tremendous growth. Many smartphone enthusiasts today don't really know how far the industry has come. That's why we wrote this article to look at the development of the telecommunications industry after World War II.
During World War II, Motorola's SCR series walkie-talkies achieved great success on the battlefield. He showed the world the power of wireless communication. It also made people want to apply them to the civilian market.
The first mobile phones
After the war, in 1946, AT & T in the United States connected a wireless receiver to the Public Switched Telephone Network (PSTN). He also officially launched MTS (Mobile Telephone Service) for civilian use.
In MTS, if a user wants to make a call, he must first manually find a free wireless channel. If it receives a channel, it will then talk to the operator, asking the other party to establish a second connection over the PSTN network.
The entire call uses half-duplex, meaning only one caller can speak at a time. During a call, the user must press the push-to-talk button on the phone. Not very convenient, right?
The method of charging or billing in MTS is also very primitive. The operator will listen to the conversation between the two parties throughout the process. It will then manually calculate the cost after the call is over and confirm the bill. This was the first commercial mobile communication system in human history.
You would probably say that cell phones were invented in the 1970s? Why did it exist in the 1940s? Don't panic, that "cell phone" is not a real cell phone. It's actually a mobile car phone. More precisely, a car half-duplex walkie-talkie.
Car mobile phone
At that time, it was impossible to invent a mobile phone using electronic technology and batteries. However, there were already many cars at that time.
At that time, the "base station" was also very large, somewhat similar to a radio and television tower. She was the only one in the city, and they had her in the center of the city. The tower covered a radius of 40 kilometers with extremely high power.
In December 1947, Bell Labs researcher Douglas H. Ring first proposed the idea of "cellular communication." This marks the beginning of the development of the telecommunications industry. He believes that instead of blindly increasing the signal transmission power, it is better to limit the signal transmission range and control the signal within a limited area (cells).
Thus, different cells can use the same frequency without affecting each other, increasing the system's bandwidth.
Although the idea of cellular communication is very good, there were many limitations at the time. So Bell Labs shelved it as just their idea.
Europe and the US are developing a car phone
In the 1950s, more and more countries began to build car telephone networks. For example, in 1952 West Germany launched A-Netz. In 1961, the Soviet engineer Leonid Kupriyanovych also invented the LK-1 mobile phone, which was also installed on a car. Later, in the Soviet Union, the "Altai" automobile telephone system was implemented, covering more than 30 cities of the country.
In 1969, the United States introduced an improved MTS car telephone system called IMTS (Improved MTS). IMTS supports full-duplex mode, automatic dialing and automatic channel search and can provide 11 channels (later 12). This is a qualitative leap compared to MTS.
In 1971, Finland launched the public mobile network ARP (Auto Radio Puhelin – Puhelin means phone in Finnish). This unit operates in the 150 MHz band but is still manually switched and is primarily used for car phone service.
Be it Altai, IMTS or ARP, it was later called "0G" or "Pre-1G" (before 1G) mobile communication technology. Now let's see what the telecommunications industry has to offer in the 1G era.
The era of 1G in the telecommunications industry
The development of semiconductor technologies provided more opportunities for the development of the telecommunications industry. This did not happen until the 70s. In 1973, Motorola engineers Martin Cooper and John F. Mitchell finally changed history forever. They invented the world's first truly mobile phone (a pocket personal mobile phone).
The phone was named DynaTAC (Dynamic Adaptive Total Area Coverage). It is 22 cm tall, weighs 1,28 kg, can talk for 20 minutes and is equipped with a huge antenna.
In 1974, the US Federal Communications Commission (FCC) approved a portion of the radio frequency spectrum for use in testing cellular networks. However, the experiment was delayed until 1977 before it officially began. At that time, two rivals - AT & T and Motorola - participated in the experiment.
The US Congress in 1964 "deprived" AT & T of the possibility of commercial use of satellite communication. In desperation, they created a mobile communications division at Bell Labs, looking for new opportunities.
1G progress is slow but steady
Between 1964 and 1974, Bell Labs developed an analog system called HCMTS (High-Volume Mobile Telephone System). The signal and voice channels of the system use FM modulation with a bandwidth of 30 kHz and a transmission rate of 10 kbit/s.
Since there was no wireless mobile standards organization at the time, AT&T established its own standard for HCMTS. The Electronics Industry Association (EIA) later named this system Interim Standard 3 (IS-3).
In 1976, HCMTS changed its name to AMPS (Advanced Mobile Phone Service). AT & T used AMPS technology to conduct FCC tests in Chicago and Newark.
Let's look again at Motorola. Motorola first developed RCC (Radio Common Carrier) technology and made a lot of money. Therefore, they strongly objected to the FCC giving the spectrum to cellular communications so as not to affect their RCC market. But at the same time, they desperately developed cellular communication technologies and made technical reserves. This is how DynaTAC was born.
After the FCC released the spectrum, Motorola conducted DynaTAC-based trials in Washington. While they were still slowly experimenting, other countries had already taken the lead.
The first commercial 1G network in Japan
In 1979, Nippon Telegraph and Telephone (NTT) launched the world's first commercial automated cellular communication system in the Tokyo metropolitan area. This system was later recognized as the world's first commercial 1G network.
At that time, the system had 88 base stations supporting fully automatic switching of calls between different cellular nodes without manual intervention. The system uses FDMA technology, the channel bandwidth is 25 kHz, it is in the 800 MHz frequency band, and the total number of duplex channels is 600.
1G in Europe
Two years later, in 1981, the countries of Northern Europe, Norway and Sweden, created the first 1G mobile communication network in Europe - NMT (Nordic Mobile Telephones). Denmark and Finland soon joined them. NMT became the world's first mobile communication network with the possibility of international roaming.
Later, NMT was introduced by Saudi Arabia, the USSR and some other Baltic and Asian countries.
Motorola released the world's first commercial 1G mobile phone
In September 1983, Motorola released the world's first commercial mobile phone, the DynaTAC 8000X.
DynaCT 8000XThis device weighs 1 kg and can talk continuously for 30 minutes. A full charge takes 10 hours, but the price is $3995.
1G in South and North America
In 1983, the United States finally remembered to build its own commercial 1G network. On October 13, 1983, Americitech Mobile Communications launched the first 1G network in the US based on AMPS technology.
Both the car phone and the DynaTAC 8000X can be used on this network. The FCC has allocated 40 MHz of bandwidth to AMPS in the 800 MHz frequency band. With this bandwidth, AMPS supports 666 duplex channels, and the bandwidth of one upstream or downstream channel is 30 kHz. Later, the FCC allocated an additional 10 MHz of bandwidth. Thus, the total number of duplex AMPS channels becomes 832.
In its first year of commercial use, Americitech sold about 1 DynaTAC 200X mobile phones, reaching 8000 users. After five years, the number of users became 200 million.
The rapidly growing number of users far exceeds the capacity of the AMPS network. Later, to increase capacity, Motorola introduced a narrowband version of AMPS technology, namely NAMPS. It divides the current 30 kHz voice channel into three 10 kHz channels (the total number of channels becomes 2496) to save spectrum and increase capacity.
UK joins 1G
Besides NMT and AMPS, another widely used 1G standard is TACS (Total Access Communication Systems), which was first released in the UK.
In February 1983, the British government announced that two companies, BT (British Telecom) and Racal Millicom (Vodafone's predecessor), would build TACS mobile communications networks based on AMPS technology.
On January 1, 1985, Vodafone officially launched the TACS service (equipment purchased from Ericsson). At that time there were only 10 base stations covering the entire London area.
The single-channel TACS bandwidth is 25 kHz, the uplink uses 890-905 MHz, the downlink uses 935-950 MHz, a total of 600 channels are used to transmit voice and control signals.
The TACS system was primarily developed by Motorola and is actually a modified version of the AMPS system. Except for the frequency band, channel spacing, frequency shift and signal transmission speed, they are completely identical.
Compared to NMT in Northern Europe, the operating characteristics of TACS are significantly different. NMT is suitable for sparsely populated rural areas of northern countries (Scandinavia). It uses a frequency of 450 MHz (later changed to 800 MHz) and has a larger cell range.
The advantage of TACS is bandwidth, not coverage distance. The TACS system has a low transmitter power and is suitable for countries with high population density and large urban areas such as the UK.
As the number of users increased, TACS later added several frequency bands (10 MHz) and became ETACS (Extended TACS). Japan's NTT developed JTACS based on TACS.
China joins 1G development
It is worth noting that the first mobile base station built by China in Guangzhou in 1987 used TACS technology, and Motorola was the partner.
In addition to AMPS, TACS and NMT, 1G technology also includes C-Netz in Germany, Radiocom 2000 in France and RTMI in Italy. These successful technologies ushered in the era of mobile communication. In fact, there was no such name as 1G in the telecommunications industry at the time it was used. Only after the advent of 2G technology were they called 1G to distinguish them.
The era of 2G in the telecommunications industry
In 1982, the European Commission for Posts and Telecommunications established the "Group of Experts on Mobile Communication", which will be responsible for the study of communication standards.
This "mobile expert group", the French abbreviation is GroupeSpécialMobile, later the meaning of this abbreviation was changed to "Global System of Mobile Communication". This is what we all now know as GSM.
The purpose of creating GSM is to establish a new pan-European standard and develop a pan-European land mobile communication system. They put forward requirements for efficient use of the spectrum, low-cost systems, portable terminals and global roaming.
In the following years, the European Telecommunications Standardization Organization (ETSI) was able to complete the development of the GSM 900 MHz and 1800 MHz (DCS) specifications.
In 1991, the Finnish company Radiolinja (now part of ELISA Oyj) launched the world's first 2G network based on the GSM standard.
As we all know, 2G uses digital technology to replace the analog technology of 1G. This significantly improves the quality of communication and the stability of the system. It also makes it safer, more reliable and lowers the equipment's energy consumption.
Besides GSM, another widely known 2G standard is CDMA launched by Qualcomm. To be precise, it is IS-95 or cdmaOne. IS-95 has two versions: IS-95A and IS-95B. The former can support peak data rates of up to 14,4 kbps and the latter up to 115 kbps.
In addition to IS-95, the United States also produced IS-54 (North America, TDMA digital cellular) and IS-136 (1996). Actually, 2G is not only GSM and CDMA. The Association of Cellular Manufacturers has developed a digital version of AMPS based on AMPS technology called D-AMPS (Digit-AMPS). It is actually a 2G standard. Another 2G standard is PDC (Personal Digital Cellular) from Japan.
The era of 2.5G
At the end of the 20th century, when the explosive growth of the Internet took place, people made a great demand for mobile Internet access. Thus, GPRS (General Packet Radio Service, General Packet Radio Service) started.
We can consider GPRS as a "plug-in" of GSM. With the help of GPRS, the network can provide a data transfer speed of up to 114 Kbps.
The first sentence about GPRS was made in 1993. However, it took another four years for the first phase of the agreement to take place in 1997. This is probably a turning point in the history of cellular communications, as well as the telecommunications industry. At that time, data transmission services became the main direction of mobile communication development.
Era 2.75G
After the launch of GPRS technology, communication operators also developed faster technology. This technology is an enhanced data rate for GSM (EDGE) development. Of course, we all know or have heard of EDGE at some point in our lives.
The biggest feature of EDGE is that it can provide twice the data transfer speed of GPRS without replacing the hardware. The world's first EDGE network was deployed by AT&T in 2003 on its own GSM network.
The era of 3G in the telecommunications industry
In 1996, the UMTS (Universal Mobile Communications System) forum was founded in Europe, which focused on coordinating research in the field of European 3G standards. The European camp represented by Nokia, Ericsson and Alcatel is clearly aware of the advantages of CDMA. Thus, they developed a W-CDMA system with similar principles.
It is called W-CDMA (Wide-CDMA) because its channel bandwidth reaches 5 MHz, which is wider than CDMA1,25's 2000 MHz.
Many people do not understand the relationship between UMTS and WCDMA. In fact, UMTS is the generic term for 3G in Europe. WCDMA is an implementation of UMTS and usually belongs to the wireless interface part. TD-SCDMA, which we will talk about later, also belongs to UMTS.
In order to be able to compete with the United States, European ETSI also jointly established 3GPP (XNUMXrd Generation Partnership Project) with Japan, China, etc. to cooperate in the development of global XNUMXG mobile communication standards.
In contrast, in the North American camp, opinions differ.
Fierce competition with 3G
Companies represented by Lucent and Nortel support WCDMA and 3GPP. However, companies such as Qualcomm teamed up with South Korea to form the 3GPP2 organization to compete with 3GPP. The standard they introduced is the CDMA2000 standard, which is based on CDMA 1X (IS-95).
Although CDMA2000 is a 3G standard, the initial peak speed is not high, only 153 kbps. Later, with the transition to EVDO (EVolution Data Optimized), the data transfer rate improved significantly. It delivered a peak download speed of 14,7 Mbps and a maximum upload speed of 5,4 Mbps.
During this period, China also launched its own candidate program operating in the 3G standard (also known as TD-SCDMA) to jointly participate in the international competition.
After fierce competition and games, the International Telecommunication Union (ITU) has finally confirmed three global 3G standards, namely: WCDMA in Europe, CDMA2000 in the US, and TD-SCDMA in China.
In terms of progress in 3G commercialization, Japan's NTT is once again leading the way.
On October 1, 1998, NTT Docomo launched the world's first commercial 3G (WCDMA-based) network in Japan.
3.75G era in the telecommunications industry
Based on UMTS, ETSI and 3GPP have developed HSPA (high-speed packet access), HSPA +, dual-channel HSPA + and HSPA + Evolution. The speed of these network technologies clearly exceeds the speed of traditional 3G, it is popularly called 3,75G.
That's because the speed of HSPA+ is so fast that it even beats early LTE and WiMAX. Therefore, at that time, some operators (for example, T-Mobile in the USA) did not immediately start building LTE. However, they upgraded the current HSPA network to HSPA+. China then did the same.
4G in the telecommunications industry
In 1999, the IEEE Standards Committee established a working group to develop standards for wireless urban networks. In 2001, the first version of IEEE 802.16 was officially released, which was later transformed into IEEE 802.16m. IEEE 802.16 is later commonly known as WiMAX (Worldwide Connection for Microwave Access).
WiMAX introduced advanced technologies such as MIMO (multi-antenna) and OFDM (orthogonal frequency division multiplexing). The download speed is much higher and this puts a lot of pressure on 3GPP.
So, based on UMTS, 3GPP is expanding the implementation of LTE (MIMO and OFDM) to compete with WiMAX. Later, it continued to develop into LTE-Advanced (2009), and the speed was increased several times.
In 2008, the International Telecommunication Union ITU issued the requirements to which the 4G standard must meet, and called it IMT-Advanced. Only 3GPP LTE-Advanced, IEEE 802.16m and TD-LTE-Advanced introduced by the Ministry of Industry and Information Technology of China are really qualified. In other words, these are true 4G standards.
On December 14, 2009, the world's first public LTE service network was opened in Stockholm and Oslo. Network equipment is supplied by Ericsson and Huawei, and the terminal is supplied by Samsung.
After a fierce industrial war, LTE finally won WiMAX and received worldwide support and recognition. WiMAX quickly lost power and was broken in the cold.
Era 5G
We don't need to talk about the development of 5G, do we? Each of us is a witness of a new history. We all witnessed how the Third Generation Partnership Project (3GPP) launched 5G (IMT-2020) to dominate the world.
Time flies, time flies. After almost a century of development, mobile networks have grown from scratch, from weak to strong. He set the wheel of history in motion and accelerated social change.
Where will the future of mobile communication go? Let's wait and see!
