Principles of mobile Internet access

GSM stands for global system for mobile communication. It refers to the global mobile communication system. This system was designed and developed by a Standardization Committee composed of major European telecom operators and manufacturers. Global connect is a famous user brand of China Mobile digital mobile phone network. The Network No. 139,138,137,136,135 belongs to the GSM digital mobile phone network, but 139,138 was the first to be activated and later expanded to so much. Their signal reception capabilities, dialing methods, coverage, roaming areas, and usage functions are consistent.
Next, let's talk about his technology. He uses digital modulation technology. One of the keys is the time division multiplexing, which means that each user selects the carrier frequency at a certain time and can only receive information at a specific time.
The main features of GSM are as follows: strong anti-theft and copy capabilities, large network capacity, rich number resources, clear calls, strong stability and non-interference, sensitive information, less dead corners of calls, and low power consumption of mobile phones.
Most of the current business volume, whether it is China Mobile or China Unicom, is voice communication. With the continuous promotion of GPRS and the continuous maturity of CDMA, the market share of GSM is declining. With the development of science and technology, no one is willing to choose a single function, the style is not trendy old man. This is also true. In addition to some old users, GSM mobile phones are mostly used by low-income users and rural areas. Although it is a long process to predict 2g to 3G, but now the pace of the gradual replacement of GSM by 2G network shows that no one can tell how long it will last... I believe you will remember the expensive Moto v998 model ..
Next, let's talk about GPRS.
The concept of GPRS is general packet radio service. The Chinese language is a universal wireless grouping service. It is a GSM-based wireless grouping exchange technology that provides end-to-end and wide-area wireless IP connection. Compared with the original GSM dial-up circuit exchange data transmission method, GPRS is a group exchange technology with advantages such as real-time online, pay-as-you-go, fast login, high-speed transmission, and easy switch, in short, GPRS is a high-speed data processing technology that transfers data to users in groups.
What are the actual applications of GPRS? Everyone must be familiar with it. Including mobile email, multimedia information service, Mobile Entertainment, mobile chat, location service, Enterprise Service, mobile search service, and mobile e-commerce.
So what is WAP most often seen on the Internet through mobile phones? WAP is a Wireless Application Protocol and a global open protocol. WAP defines a universal platform and converts the current HTML language information on the Internet to the information described in WML, which is displayed on the display screen of mobile phones or other handheld devices. He does not rely on a certain network. Today's WAP Service may continue to exist after 3G arrives, but the transmission rate is faster and protocol standards will also increase.
Next, let's talk about CDMA. I am not very interested in CDMA myself ..... CDMA is code division muliple access, which means code division multiple access. Like GSM, CDMA is also a mobile communication system. It is a brand-new and mature wireless communication technology developed from the spread-spectrum communication technology, a branch of digital technology. CDMA does not assign a fixed frequency to each user, but enables each channel to use all the spectrum that can be provided. CDMA codes each group of calls using pseudo-random numbers.
He is characterized by a high access rate, a clear voice call with almost no noise, not easily dropped, a green phone, good confidentiality, and multimedia technology.
The first CDMA mobile phone in China is Hisense c2101.

Continue .. Let's talk about GPS. GPS is a global positioning system. It is a global wireless navigation and positioning system composed of 24 satellites and ground stations, our 7710 feature works with a Bluetooth GPS receiver. GPS consists of three major parts: Space constellation, ground monitoring, and user equipment.

 

Source: http://blog.csdn.net/yangzhongxuan/article/details/4224112