phone system

At present, the mobile phone formats include GSM, CDMA, 3 G, since three mobile phone came out today, the first generation of simulation system through mobile phone (1 G), the second generation GSM, TDMA etc digital mobile phones (2 G), 2.5 generation mobile communication technology CDMA and the third generation mobile communication technology 3 G.

GSM, CDMA and 3 G comparison

GSM digital mobile communication system is the major European telecom operators and by the manufacturer of the standardization of the committee, it is designed in the cellular system based on development and into. Including GSM900MHz, GSM1800MHz and GSM1900MHz and several other frequency band. GSM system several important characteristics: good ability to guard against theft kao, network capacity, rich resources, and number clear communication, strong stability is not easy to interference, information sensitive, calling blind Angle less power consumption, mobile phone lower.

CDMA is the abbreviation of CDMA (Code Division Multiple Access), it is in digital technology branch of spread spectrum communication technology, developed on a new and mature wireless communication technology. It can meet the market for mobile communication capacity and quality of high demand, with high efficiency and voice quality spectrum good, the secrecy of simulation.one of strong, low and electromagnetic radiation small, large capacity, covering area etc, to reduce the amount investment and reduce operating costs. 3 G is the third generation mobile communication technology, is the next generation of mobile communication system of intellectuals. 3 G system for users to provide better voice, text and data services. And the existing technology, for comparison, the main advantage of the 3 G technology is can substantially increase the system capacity, improve the communication quality and speed of data transmission. In addition to use in the different network seamless roaming technology, which will wireless communication system and Internet connection, and to move up to end users with more advanced services more.

Compared with GSM mobile phones CDMA mobile phone, CDMA mobile phone has the following advantages: CDMA mobile phone use of advanced switching technology: soft switching technology (i.e. switch is first in good again after the break), making phone calls to CDMA mobile phone and fixed phone can be comparable; Use CDMA network, operators of investment is to reduce, it is CDMA mobile phone charges of reserved space; cut For the extension frequency communications with the basis of a modulation and multiple address communication mode, its capacity than simulation technology high 10 times more than the GSM network, about 4 times; Based on the broadband technology of mobile communication makes the CDMA video applications become possible, and thus causes the handset can only send short phone call from and information service in the narrow to broadband multimedia applications.

Mobile phone system

All of the current cell phones through the radio waves, mobile phone and communication cycle more mobile phones can be used in the same frequency is strategic two or three different frequency band mobile phones.

Dual mode mobile phone and multimode mobile phone, which can be used in two or DuoGe different mobile network of mobile phones, such as GSM and CDMA, GSM and PHS, 2 G and 3 G, etc. Although these cell phones in the price change in single-mode phone, but give users a new choice, providing better flexibility. They now as a standard of the transition, short period of products, in improving the efficiency of the customer, network and operators are cheaper option.

GSM full name is: Global optimisation techniques for Mobile Communications System, the development of European digital Mobile phone network standards, it's development purpose is to let the world to use a Mobile phone network standard, let users to use a Mobile phone can traveled across the world. GSM system including 900:900 MHz, GSM GSM1800:1800 MHz and GSM-1900, 1900 MHz and several other frequency band.

GSM system several important characteristics: good ability to guard against theft kao, network capacity, rich resources of mobile phone number, and the average blurs clear, strong stability is not easy to interference, information sensitive, calling blind Angle less power consumption, mobile phone low. At present on the world of both major GSM system for GSM 900 and GSM1800, because used different frequency, so for mobile phone is endless also and same. The former development time is earlier, use more, the development of the latter country was late, use countries also less. Physical features, the former spectrum is low, the wavelengths longer, penetration is bad, but the transmission distance, and mobile phone launch power is stronger, power consumption, so large standby time is short; While the latter spectrum is higher, relatively short wavelengths, penetration, but the transfer of better, its mobile phone short distance from the launch of small power, standby time is correspondingly more long.

CDMA (Code Division Multiple Access (CDMA) is a Division Multiple Access) Code-the abbreviation of technology, is in recent years in the digital mobile communication emerge in the process of a kind of advanced wireless spread spectrum communication technology, it can meet the market for mobile communication let quantity and quality of high demand, with high efficiency and voice quality spectrum good, the secrecy of simulation.one of strong, low and electromagnetic radiation small, large capacity, the covering area etc, to reduce the amount investment and reduce operating costs.

The earliest qualcomm CDMA by the United States launched with GSM, CDMA, same had two generations, and 2.5 g and 3 generation technology. China unicom will launch in the second half of this year the CDMA belong to 2.5 generation technology. CDMA is considered to be the third generation mobile communication technology first choice, the current standard have WCDMA, CDMA2000, td-scdma.

What is the CDMA2000?

CDMA2000 TIA standards organization used to refer to is the name of the third generation of CDMA. Apply to 3 G standard called CDMA of TIA 2000, this technology IS itself IS called CDMA2000.

The first phase of the CDMA2000 1 x, also known as the make have existing IS 95 system of communication can be the whole system capacity doubled, and can be added to the data rate IS as high as 614 KBPS.

More than 1 x higher CDMA2000 technology advances include 1 xEV (high speed data rate). By QCT launched MSM5000 ™ CDMA2000 chipset solutions backward compatibility cdmaOne (IS 95 CDMA).

CDMA2000 standard by three GPP2 organization, including the Release version for 0, Release A, ev-do and EV-DV, Release the main characteristic is used 0 ANSI-41 D based on core nets, in the wireless access network and core nets adds support service network group entity, this version has been stable. Unicom CDMA will be opening of the second phase of the project by a single carrier is the version, the highest rate can reach 153.6 downlink kbit/s. Release A is Release 0 of the strengthened, and the single carrier highest rate can reach 307.2 kbit/s, and support voice business and grouping of concurrent business. Ev-do using single carrier support data business, can be in 1.25 MHz standards in the carrier and at the same time providing the voice and high speed packet data service, the highest rate can reach 3.1 Mbit/s

3 G is the abbreviation of 3 rd Generation, refers to the third Generation mobile communication technology. The first generation of simulation system relative mobile phone (1 G) and the second generation GSM, TDMA etc digital mobile phones (2 G), third generation mobile phone generally speaking, it is to point to will wireless communication and Internet and multi-media communication with a new generation of mobile communication system. It can deal with images, music, video, etc DuoZhong media forms, provide including surfing the web, conference calls and e-commerce, DuoZhong information service. In order to provide this service, the wireless network must be able to support different transmission speed, that is in the indoor and outdoor and driving environment can support at least 2 Mbps respectively (megabytes per second), 384 KBPS (bits/SEC) and 144 KBPS transmission speed.

3 G technology standards

The international telecommunications union (ITU) in May 2000 sure W-CDMA, CDMA2000 and TDS-CDMA three mainstream wireless interface standards, writing 3 G technology guidance documents "2000 international mobile communications plan (IMT 2000).

W-CDMA

That is WidebandCDMA, also known as CDMADirectSpread, meaning broadband.