Mobile phone network system and baseband chip | Aiguo Computer - 上海419贵族宝贝-上海后花园1314-上海品茶网-阿拉爱上海

The network system of mobile phone is the type of network. The types supported vary according to the built-in baseband of mobile phone. The current network systems in China include GSM, CDMA, TD-SCDMA, WCDMA, CDMA2000, etc. The types supported by mobile phones will vary depending on the main system of each operator.

The frequency bands commonly used by mobile phones in China mainly include CDMA1X and 800MHZ bands occupied by CDMA mobile phones; 900/1800/1900 MHz frequency band occupied by GSM mobile phones; 900/1800MHz frequency band occupied by GSM1X dual mode in recent two years; 900/1800/1900/2100 MHz frequency band occupied by 3G.

When it comes to the frequency bands supported by mobile phones, first of all, it should be clear that the frequency bands are actually hard divided, which is mainly due to the limited frequency resources. At present, the Ministry of Information Industry is mainly responsible for related matters in China.

The mobile phone network system mainly includes GSM, CDMA and 3G. Since its inception, the mobile phone has experienced the first generation analog mobile phone (1G), the second generation GSM, TDMA and other digital mobile phones (2G), the 2.5 generation mobile communication technology CDMA and the third generation mobile communication technology 3G.

GSM mobile phone
GSM digital mobile communication system is designed by the standardization committee composed of major European telecom operators and manufacturers. It is developed on the basis of cellular system. It includes several frequency bands such as GSM900MHz, GSM1800MHz and GSM1900MHz. The GSM system has several important features: good anti-theft copy ability, large network capacity, rich number resources, clear calls, strong stability, not easily disturbed, sensitive information, less dead space for calls, and low power consumption of mobile phones.

CDMA mobile phone
CDMA is the abbreviation of Code Division Multiple Access. It is a new and mature wireless communication technology developed from the spread spectrum communication technology, a branch of digital technology. It can meet the market's high requirements for mobile communication capacity and quality. It has the characteristics of high spectrum utilization, good voice quality, strong confidentiality, low call drop rate, small electromagnetic radiation, large capacity, wide coverage, etc. It can greatly reduce investment and reduce operating costs.

China has three major telecom operators, China Mobile, China Unicom and China Telecom. Each operator has different network systems. China Mobile mainly promotes GSM and TD-SCDMA networks, China Unicom mainly promotes GSM and WCDMA networks, and China Telecom mainly promotes CDMA and CDMA2000 networks. Because both China Mobile and China Unicom support GSM networks, we generally do not need to deliberately distinguish between 2G cards, Just use the 3G card because the 3G network systems of China Mobile and China Unicom are different, so we should pay attention to the difference. The telecom card is different from China Unicom in the network system of 2G and 3G, so we should always pay attention to the difference. Of course, with the continuous upgrading of baseband chips, the support of mobile phones in the network system is becoming increasingly perfect, so what is baseband chips? The baseband chip is used to synthesize the baseband signal to be transmitted or decode the received baseband signal. Specifically, when transmitting, the audio signal is compiled into baseband code for transmission; When receiving, the received baseband code is interpreted into an audio signal. At the same time, it is also responsible for the compilation of address information (mobile phone number, website address), text information (SMS text, website text) and picture information. Different types of baseband chips support different network systems, so when you buy a mobile phone, you must know in advance whether the network system supported by this mobile phone is compatible with the network type of your phone card.