The first two-way radiotelephone systems between mobile objects appeared about 40 years ago. Communication was carried out at fixed frequencies. The transmitted signals occupied a wide frequency band on the air. With the development of traditional radio communication technology, problems have arisen related to the limited frequency resource and low bandwidth of such systems. The idea of creating mobile cellular communication systems was based on dividing the served territory into small zones (cells). In each of which, as a rule, one base station is located.
The history of the development and generation of mobile cellular communications, standards for mobile communications 1G, 2G, 3G, 4G, 5G, the main characteristics of generations of mobile cellular communications.
This principle of organizing cellular communications allows you to increase the number of subscribers and improve communication quality by reusing the same frequencies in different cells. In the early 1980s, commercial mobile cellular systems using analog frequency modulation for voice transmission were deployed in a number of countries..
One of the first to provide system services NMT-450 (Nordic Mobile Telephone), established in 1981 by a number of Scandinavian countries. Soon there were other systems operating in the frequency range 400-500 MHz. These were standard systems S-450 (Germany), Radiocom-2000 (France), RTMS-101H (Italy).
The most powerful impetus to the development of new mobile radio systems was given when the intensive development of the frequency range 800-900 MHz began. With the advent of systems like Amps (USA), NMT-900 (Scandinavian countries), Tacs and ETACS (England), HCMTS, J-tacs (Japan), the era of mobile cellular communication systems (SMS) has begun. All of the listed standards are analog and belong to the first generation of cellular communication systems..
All analog standards use frequency modulation for voice transmission and frequency modulation for transmission of control information (or signaling). To transmit information of different channels, different parts of the frequency spectrum are used. Frequency division multiple access (FDMA) is applied. With channel bands in various standards from 12.5 to 30 kHz.
Directly connected with this, the main disadvantage of analog systems is the relatively low capacity. Other disadvantages:
Ability to listen to conversations.
The presence of doubles.
Congestion of the frequency range due to its inefficient use.
2nd Generation 2G Mobile Cellular Standards.
The development of digital technologies on the one hand and frequent examples of the exhaustion of subscriber capacity by analog systems (especially in large cities) on the other hand led to the development of second-generation systems.
The first projects of second-generation digital cellular communication systems appeared in the early 90s. They differed from analog systems in two fundamental qualities:
The ability to use spectrally efficient modulation methods in combination with time (TDMA) and code (CDMA) channel separation. Instead of traditionally used in analogue frequency division multiplexing (FDMA) systems.
Providing users with a wide range of services through the integration of voice and data transmission with the ability to encrypt (classify) data.
In the USA, by 1992 a dual-mode analog-to-digital system was developed, the standard was named D-amps, or IS-54 (IS stands for Interim Standard, that is, the “intermediate standard”). A common European standard has been developed in Europe GSM (GSM 900 900 MHz band). Practical application of the standard began in 1991..
Another version of the digital standard, similar in technical characteristics to D-AMPS, was developed in Japan in 1993. PDC. Personal Digital Cellular literally “personal digital cellular communications”.
D-AMPS standard becomes fully digital in version IS-136, which began to be applied in 1996. The GSM standard in 1989 went to the development of a new frequency range of 1800 MHz. A wider operating frequency band, combined with smaller cell sizes, made it possible to build cellular networks of significantly greater capacity. In 1996, it was decided to name her in GSM 1800. PCS personal communication system operates in the US in the 1900 MHz band.
Operation of the first commercial mobile cellular system based on technology CDMA was launched in September 1995 in Hong Kong. The CDMA system is mainly used in cases where you want to build a network of high capacity or with higher quality voice transmission.
2.5G Intermediate Mobile Cellular Standards, GPRS, EDGE, CDMA Technologies.
General Packet Radio Communication Gprs (English General Packet Radio Service) is an add-on over GSM mobile communications technology that performs packet data transmission. GPRS mode allows the user of a mobile phone to exchange data with other devices in the GSM network and with external networks. Including internet. GPRS involves charging according to the amount of information transmitted / received, not time.
Technology EDGE (English Enhanced Data rates for GSM Evolution) is a further development of GPRS. It differs only in the way of encoding data, which allows for transferring a larger amount of data in one time slot. EDGE is sometimes called 2.75G.
Mobile digital data technology 1xRTT (One Times Radio Transmission Technology) is based on CDMA technology. It uses the principle of packet switched transmission. This technology officially refers to the standards of the third generation. Nevertheless, it is often compared with networks of generations 2.5G and 2.75G, with which it has a lot of similarities and can well be compared.
Key Features of 1G, 2G, 3G, 4G, 5G Mobile Cellular Generations.
3rd Generation 3G Mobile Cellular Standards.
Third generation digital systems are based on CDMA code division multiple access. The first 3G standard was developed in 1992-1993 in the United States and was called IS-95 (800 MHz band). It began to be applied from 1995-1996 in Hong Kong, USA, South Korea. And in the USA, a version of this standard for the 1900 MHz band began to be used..
At the same time, a standard was developed UMTS, most widespread in Europe and the CIS. The basis of this standard was the technology of W-CDMA, which is one of the options for CDMA. Depending on the telephone supporting UMTS networks, as well as being in the coverage area of this network, communication can be provided either via GSM or through UMTS.
Of the family of 3G communication standards, the most widespread in Europe UMTS uses the frequency range of 2100 MHz. For the full operation of the system requires several frequency bands (MHz):
These are the features of the standard for high-speed data exchange..
3.5G Intermediate Standard for Mobile Communications, HSPA.
High Speed Packet Data Hspa (High Speed Packet Access) is a technology that is a further development of the UMTS standard. It is based on the HSDPA standard, which regulates the transfer of data from the base station to the subscriber. And the HSUPA standard governing transmission from subscriber to base station.
4th Generation 4G Mobile Cellular Standards.
The most frequently mentioned technologies of the 4G generation and claiming to be LTE, Mobile WiMAX, Hspa+. The most popular networks are WiMAX and LTE. The world’s first LTE network in Stockholm and Oslo was launched by the TeliaSonera / Ericsson alliance in 2008. The estimated value of the maximum data transfer rate to the subscriber was 382 Mbit / s, 86 Mbit / s from the subscriber.
WiMAX standard is not all 4G. It is not integrated with previous generation networks such as 3G and 2G. And also due to the fact that in the WiMAX network, the operators themselves do not provide traditional communication services. Such as voice calls and SMS, although their use is possible when using various VoIP services. The International Telecommunication Union has allowed HSPA + networks to be called 4G, as they provide appropriate speeds.
As for UMTS, there is a similar situation with operating ranges for broadband access systems like Wi-Fi and WiMax. They use frequencies of 2.2-6.5 GHz. The bands 3400-3500 MHz and 5650-5725 MHz are already open, subject to compliance with electromagnetic compatibility with existing systems.
In practice, this means limiting the power of the transmitter, and hence the coverage area for one base station. But for the ranges 2300-2400 MHz, 2500-2570 MHz, 2620-2690 MHz, 3500-3600 MHz, 3600-3800 MHz, 5470-5650 MHz, 5725-6425 MHz, conversion is also necessary.
5th Generation 5G Mobile Standards.
The fifth generation of mobile communications is being developed based on telecommunication standards following existing standards. 4G / IMT-Advanced. There are currently no standards for deploying 5G networks.
Based on the fact that new generations of cellular standards have appeared on average every 10 years. From the first 1G (NMT) in 1981, 2G (GSM) in 1992, 3G (WCDMA / FDMA) in 2001, 4G (3GPP LTE, WiMax) in 2010. Implementation of the international 5G standard can be expected in the region of 2020.
It is anticipated that 5G mobile cellular technologies will provide higher throughput than 4G technologies. This will ensure:
Greater mobile broadband availability.
Using device-to-device modes (literally. “Device with device”).
Extremely reliable large-scale communication systems between devices.
Shorter delay time.
Less battery power than 4G equipment.
Based on the materials of the book Mobile communication systems.
N.N. Busnyuk, G.I. Melyanets.