3G (from the English. Third generation - third generation), 3rd generation mobile communication technology - a set of services that combines both high-speed mobile access with Internet services, and radio technology, which creates a data channel. Currently, due to massive promotions, this term most often refers to UMTS technology with an HSPA add-on .
Content
Standard Feature
Third-generation mobile communications are being built on the basis of packet data transmission. Third-generation 3G networks operate on the border of decimeter and centimeter ranges. They allow you to organize video telephony, watch movies and various content on your mobile phone.
3G includes 5 standards of the IMT-2000 family (UMTS / WCDMA, CDMA2000 / IMT-MC, TD-CDMA / TD-SCDMA (China's own standard), DECT and UWC-136).
The most widespread in the world are two standards :
- UMTS (or W-CDMA ) and
- CDMA2000 (IMT-MC),
which are based on the same technology - CDMA (Code Division Multiple Access).
In Russia, the IMT-MC was available until 2016 on radio frequencies in the 450 MHz band (CDMA450).
CDMA2000 Technology
CDMA2000 technology provides an evolutionary transition from narrowband systems with code division multiplexing IS-95 (the American standard for second-generation digital cellular communications) to CDMA systems of the “third generation” and is most widely used in the North American continent, as well as in the countries of the Asia-Pacific region .
UMTS Technology
The UMTS technology (Universal Mobile Telecommunications System - a universal system of mobile telecommunications) was developed for the modernization of GSM networks (the European standard for second-generation cellular communication), and has become widespread not only in Europe but also in many other regions of the world .
UMTS standardization work is coordinated by the 3GPP (Third Generation Partnership Project) international group, and CDMA2000 standardization is coordinated by the 3GPP2 (Third Generation Partnership Project 2) international group created and coexisting within the ITU.
Prevalence
According to Wireless Intelligence , at the end of November 2006, there were 364 million 3G subscribers in the world, of which 93.5 million were connected to UMTS networks and 271.1 million to CDMA2000. The largest operator is the Japanese NTT DoCoMo , as of April 2010 the number of subscribers exceeds 56 million people [1]
Basic Services
In 3G networks, two basic services are provided: data transmission and voice transmission. According to ITU regulations (International Telecommunications Union), 3G networks must support the following data transfer rates:
- for subscribers with high mobility (up to 120 km / h) - at least 144 kbit / s;
- for subscribers with low mobility (up to 3 km / h) - 384 kbit / s;
- for motionless objects - 2048 Kbps.
Trends
The main trends of 3G networks:
- the prevalence of data-cards traffic ( USB modems , ExpressCard / PCMCIA cards for laptops) over the traffic of 3G phones and smartphones;
- a constant reduction in the price of 1 Mb of traffic due to the transition of operators to more advanced and efficient technologies.
Cliff Protection
In networks with code division multiplexing , including 3G, there is an important advantage - improved protection against communication breaks in motion, due to the use of the so-called “soft handover ”. As you move away from one base station, the client “picks up” another. She begins to transmit more and more information, while the first station transmits less and less, until the client leaves her service area at all. With good likelihood of a break is completely eliminated by a system of such “pickups”. This differs from the behavior of systems with frequency and time division of channels ( GSM ), in which switching between stations is “hard” and can lead to delays in transmission and even disconnections.
See also
- 4G