support Frequency

GSM occupy bandChina mobile GSM occupied primarily 900MHZ and 1800MHZ band. 1800MHZ is essentially due to the number of mobile phone users in the mobile communication network, system is running state and, eventually, to load the phone in communication easily when they appear similar drops, crosstalk, voice quality is bad, online fault phenomena as. In order to solve these fault phenomena, more and more mobile operators and manufacturers began to realize the urgency to solve this problem, and constantly take relevant measures to further expansion of mobile network system, so GSM1800Mhz will emerge as The Times require, also called DCS1800 (digital cellular systems, it appears,) that is based on the network GSM900, 1800, double-frequency into reality.Using mobile phone, GSM900 / GSM1800 dual-frequency GSM900 users can switch between freedom and GSM1800, can effectively avoid ever to drop words, and quality issues such as calls, using only GSM900 nets of previous calls more convenient.In order to further expand the mobile network system and improve the operation capacity of mobile communication, the sound quality in the market recently launched a "three frequency.The so-called "three frequency" is contained 3 working frequency, the three working frequency is GSM900Mhz, DCS1800Mhz and PCS1900Mhz, repeating the process, the so-called "three frequency mobile phone" means to receive GSM900M, DCS1800Mhz and PCS1900Mhz these three PinLvDuan signal, choose a band, the choice of signal intensity, the base of the signal, if one party can free disconnected, turn to another frequency signal. It is actually expanded phone connection. In some mobile phone users were concentrated regions, especially suitable for mobile phone use three frequency, three frequency cell phones can flexibly in GSM900, DCS1800 and PCS1900 switching between to always keep call quality unceasingly and calls. PCS1900 trillion nets, is North America (the United States, Canada and European countries communication network field commonly used nets.Due to the mobile phone can also work in the frequency of three different frequencies segment, so the phone has three frequency characteristics of three kinds of network. From technical Angle, GSM1800 because of high frequency signals penetrate, strong ability in high-rise, therefore the complex environment of good quality and communication covered call, And PCS1900 channel, in North America (the United States, Canada and Europe have good communication ability, this is for those who went from intercontinental between people they need, provides the service.For operator speaking, three frequencies of constructing Internet, thoroughly GSM900 alleviates the existing problem of the frequency and the capacity of the network, and further optimization of hotspots, effectively relieve, peak traffic volume, and thus more connection.For users, three of its mobile phone frequency influence will be the most far-reaching, also will be the most practical, because use mobile phones, through three frequency of roaming, three frequency network towards phenomenon will reduce the use of mobile phones will be free. Three frequency mobile users can freely in five continents 120 countries.3G,The simplified form is the 3GPP 3G, 3GPP in English full name is: the 3rd Generation of Chinese Partner Project is: the third Generation partnership programs. Now "3G communication" is become widely mouth, so you know exactly what is 3G communications? So-called 3G, actually it's called the 3rd Generation, Chinese meaning is refers to the third Generation digital communication. In 1995, the first generation of digital mobile only voice calls, From 1996 to 1997 and the second generation digital mobile phones will increase the amount of data, such as function accept email or a web page, The third generation and the main difference between two generations before the transmission of voice and data on the speed of ascension, it can handle image, music, video, provide various media forms including web browsing, telephone conference, e-commerce, various information service. The first generation of analog phones relative responsor 1G (GSM) and the second generation digital mobile phones, TDMA (2G),The name is various, 3G telecommunications regulations of international report couplet additionally for "IMT - 2000" (2000), international mobile phone moving, the European telecommunications standards titans are referred to as "UMTS" general move move communication system. This standard, move move by moving speed in the terminal, the transfer data rate for 144kbps, outdoor stationary or walk rate for 384kbps and indoor for 2Mbps. But the request does not mean that users can rate can reach 2Mbps, because indoor rate will also depend on building the detailed planning and organization and frequency of collaboration tightness operators.The international telecommunications union (ITU) to determine the 3G wireless communication interface standards were three mainstream W - CDMA (uwb), multiple access code points (carrier division multiplexing CDMA2000 spread-spectrum CDMA modem) and TDS - (CDMA). Access time synchronization One W - CDMA standards in Europe and Japan mainly originated from the early third-generation wireless research activities, this system in the existing GSM network on system provider for use, can be easily in transition, the standard of supporters are mainly in Europe, Japan and South Korea. Late last year, the U.S. move move business branches and AT&T announced for selecting WCDMA third generation business platform. CDMA2000 system is mainly composed of north American qualcomm dominated the company, it is relatively low cost of construction, mainly including Japan, South Korea and north American supporters such regions and countries. The td-scdma standard is first proposed by China and the RTT) wireless transmission technology (on the basis of international cooperation, completed td-scdma standard and become a member of the standard CDMA TDD, this is the first move move systems in China, China's third generation to move move communication development of contribution. In Europe, America and presents the competition of 3G standards, China td-scdma 3G standards has officially become one of world, which marks the dynamic communication field in China has moved into the lead.WCDMA: WCDMA Wideband Code name is (Division for Access), Chinese translated as "broadband Access points more Code, WCDMA originated from Europe and Japan several technical integration. It adopts the MC FDD full-duplex mode, and GSM network has good compatibility and interoperability. As a new technology, it is not in the aspects of technical sophistication, but its CDMA2000 advantage is widely used for the GSM upgrade its bring convenience. Therefore, time also by each big firms. Using the latest WCDMA asynchronous transfer mode (ATM) micro transmission agreement, can allow in line to send more voice call by now, the number of calls to raise 30 300 in populated areas circuit will not easy jam. WCDMA USES the straight enlargement (MC) mode, 5MHz bandwidth for carrier, it can support 384Kbps 2Mbps to differ, the speed of data transmission in high-speed moving state, can provide 384Kbps transmission rate, low speed or indoor environment, can offer high 2Mbps transmission rate. But the GSM system can transmit 9.6 Kbps, fixed line is the rate of Modem 56Kbps, thus the broadband wireless communications WCDMA is.In addition, in the same transmission channel, and it can also provide circuit switching and subcontractor service, therefore, the exchange of consumer can exchange with the phone, then by the exchange of Internet access, this technology can improve the efficiency in the use of mobile phone moving, we can exceed the at the same time can do voice or data transmission service.

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Frequency

Using spread-spectrum CDMA 1X SR1 rate for namely, to channel and reverse channel with 1.2288 chip rate Mbit/s single carrier direct way. Spread series, Therefore it can be easily and IS - 95 (A/B), backward compatibility, smooth transition. Because of using reverse 1X CDMA coherent demodulation, rapid prior to work, transmit diversity, Turbo coding techniques, the capacity of more than 95 - IS greatly improved. In the same condition, the average voice business, in roughly 95 - ahead for the capacity of the system. CDMA network can be used as a voice business 1X bearing platform, also can be used as a wireless access Internet packet data load platform, can provide users with the traditional voice business, also can provide end-to-end packet transmission mode of data.CDMA 800MHZUnicom CDMA network in the main telecoms handed unicom, make great 800MHz won easily unicom bi-directional frequency band on resources, which 10M is made with the frequency of precious China unicom. Therefore, China unicom is using its resources in 800MHZ frequency established CDMA network.By China unicom CDMA network construction and operation of unity, the exclusive right to the market space is very obvious. Has the support of China unicom CDMA network, many new value-added data can be realized, which is likely to win business users more code division multiple access (CDMA).2000MHZ CDMACDMA2000 is used to refer to the standard organization TIA for CDMA name. Applicable to 3G CDMA TIA norms IS called the technology itself - 2000, called CDMA2000.The first phase of the   CDMA2000 1x also called, with existing 95 - IS that the communication can be the whole system capacity doubled, and will be increased to $614kbps data rate. 1x higher than  CDMA2000 technology progress include 1xEV (high speed data rate).  QCT launched by MSM5000 ® chipset CDMA2000 solution decentralization cdmaOne (CDMA) IS - 95.By 3GPP2 CDMA2000 standards group, including Release 0, Release version, ev-do and EV - Release DV the main characteristic is used 0-41D core based on the ANSI, in the wireless network access and core business of increasing support group, this version has network entity. Unicom CDMA will be opening phase ii project using this version, single carrier rate can reach the highest downlink 153.6 kbit/s. Release A Release is strengthened, single carrier of 0 307.2 can reach the highest rate kbit/s, and support the voice business and grouping of business concurrently. Ev-do using single carrier to support data business, can be in the standard carrier of 125 MHz, meanwhile, we also provide voice and data services, the highest rate of grouping can reach 3.1 Mbit/s

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