How to understand the meanings, differences and connections of WAP, GSM, GPRS and CDMA?

I won't repeat the concept between them. Other friends have answered you in detail, so I will talk about some of their connections and differences.

What is GPRS?

GPRS, the abbreviation of General Packet Radio Service, is a new packet data bearer service developed on the existing GSM system. The fundamental difference between GPRS and existing GSM voice system is that GSM is a circuit-switched system, while GPRS is a packet-switched system. Therefore, GPRS is especially suitable for intermittent, sudden or frequent, small data transmission, as well as occasional large data transmission. This function is suitable for most mobile Internet applications.

What are the advantages of GPRS?

Compared with the original GSM dial-up circuit-switched data transmission mode, GPRS is a packet switching technology, which has the advantages of "real-time online", "quantity charging", "fast login", "high-speed transmission" and "free switching".

1) Real-time online

"Real-time online" means that users keep in touch with the network at any time. For example, when a user accesses the Internet, a mobile phone sends and receives data on a wireless channel. Even if there is no data transmission, the mobile phone remains connected to the network. Users can not only initiate data transmission, but also start push service from the network at any time, unlike ordinary dial-up internet access, which requires redialing to access the internet.

2) Charge by quantity

Users can always charge online according to the number of data packets sent and received by users. When there is no data traffic, even if the user hangs up the internet, there is no charge. Give a very vivid and interesting example: it is free to be in a daze.

3) Fast login

Once GPRS users are turned on, they are always connected to the GPRS network. Every time they use it, they only need an activation process, which usually takes 1-3 seconds to log on to the Internet immediately. Fixed dial-up Internet access requires dialing, verifying user name and password, logging in to the server and other processes, which takes at least 8- 10 seconds or even longer.

4) high-speed transmission

GPRS adopts packet switching technology, and the highest theoretical data transmission rate can reach 17 1.2kb/s, but the actual speed is limited by coding and mobile phone terminals, which may be different. The rate of circuit-switched data service is 9.6Kbits per second, so the relationship between circuit-switched data service (CSD) and GPRS is just like the difference between a 9.6k modem and a 33.6K or 56K modem.

5) Free switching

GPRS also has the advantage that data transmission and voice transmission can be conducted or switched at the same time. In other words, users can use their mobile phones to surf the Internet while answering voice calls. For example, the original telephone dial-up internet access, after access, can not make calls, can not answer the phone, and GPRS is similar to the concept of fixed telephone ISDN, telephone internet access is correct.

What can GPRS bring to users? Especially different from existing GSM applications?

GPRS mobile data service can provide users with rich application services, such as (1) mobile commerce, including mobile banking, mobile financial management, mobile transactions (stocks, lottery tickets) and so on. (2) Mobile information services: information on demand, weather, travel, services, yellow pages, news and advertisements. (3) Mobile Internet services: web browsing, e-mail, etc. (4) Mobile medical care, etc. (5) Location-based services: location inquiry, navigation of hotels and similar service industries, etc. (6) Multimedia services: videophone, multimedia information transmission, online games, music, video on demand, etc. (7) Personal services: PIM and other services tailored for individuals.

What is the concept of "always on"?

"Always on" means that users keep in touch with the network at any time. For example, when a user accesses the Internet, a mobile phone sends and receives data on a wireless channel. Even if there is no data transmission, the mobile phone keeps the connection with the network, and there is no need to initiate data transmission again, unlike ordinary dial-up internet access, which requires redialing to access the internet.

What is the speed of GPRS? How can the highest rate supported by theory be truly realized?

At present, the theoretical maximum rate supported by the GPRS network constructed by China Mobile is 17 1.2kbps, which is realized under the condition that the coding method is CS-4, the wireless environment is good and the channels are sufficient.

When GPRS reaches the theoretical maximum of 17 1.2kbps, it can fully support some multimedia image transmission services and other applications with high bandwidth requirements, but the actual data transmission rate is affected by the network coding method and the factors supported by the terminal. At present, the access speed of users can be divided into 20k, 40k, 60k,115.2k. ..

How long is the GPRS access time?

The GPRS mobile phone can be attached to the GPRS network as soon as it is turned on, that is, it has established contact with the GPRS network, and the attachment time is generally 3-5 seconds; When using GPRS data service, the activation process is needed, which is generally 1-3 seconds. After activation, it has been fully connected to the Internet.

Will GPRS affect normal calls?

No. Using GPRS to surf the Internet, you can also answer and make calls normally.

Can GPRS make phone calls and surf the Internet at the same time?

It depends on the support of the mobile phone. GPRS mobile phones are divided into three grades: Class A mobile phones can also surf the Internet, send and receive emails, etc. While making voice calls, that is, voice calls and data transmission can be carried out at the same time; Class B and Class C terminals cannot transmit data when making a phone call, so they need to switch between data transmission and voice call. Among them, Class B terminals can automatically switch, temporarily suspend GPRS data transmission when making a call, and resume data transmission after the call. Class c terminals need to be manually switched. The most common mobile phone on the market is Class B mobile phone.

What are the technical advantages of GPRS compared with WAP?

At present, the bearer of WAP is circuit-switched (CSD) mode, while the transmission of data by GPRS is packet-switched mode. In the circuit-switched mode, data and voice cannot be carried out at the same time, and the charging mode is also based on the duration. Because GPRS is packet-switched, the utilization rate of network resources is much higher than that of circuit-switched. GPRS can transmit voice and data at the same time, and can be charged according to the generated traffic.

In fact, WAP itself is not comparable to GPRS, and the existing WAP content can be browsed and applied on GPRS, but GPRS makes the existing CSD WAP faster, more convenient and more reasonable, and the service content of WAP will be greatly promoted and improved because of the technological progress of the network.

Will GPRS replace WAP?

WAP now uses the GSM data service of CSD (Circuit Switched Data), and in the future WAP can use GPRS, a new GSM network, as the bearer.

GPRS will not replace WAP, they belong to different categories. GPRS and GSM data service based on CSD are both roads, while WAP is a car on the road. WAP is now driving in two lanes, and GPRS has increased the data transmission speed to eight lanes. It can be said that GPRS enhances WAP service, and the content on existing WAP can also be browsed and applied through GPRS.

What are the technical advantages of GPRS compared with GSM?

GPRS is a packet-switched data bearing and transmission mode developed on the basis of GSM. Compared with the original GSM, GPRS has obvious advantages in carrying and supporting data services: it makes more effective use of wireless network channel resources, especially suitable for sudden and frequent small-flow data transmission; The supported data transmission rate is higher, and the theoretical peak reaches115 kbps; The charging method is more flexible and can support charging according to data flow; GPRS can support voice calls and so on while transmitting data.

What is the relationship among GPRS, WAP and HTTP?

For example, two users use ordinary fixed telephones and mobile phones to make phone calls. Here, GPRS is equivalent to telephone lines and telecommunication networks for voice transmission, WAP and HTTP are equivalent to Cantonese or Mandarin spoken by users, and users say things like "Have you eaten?" It is the specific content transmitted on WAP and HTTP. So GPRS and WAP are different concepts.

What is the relationship between GPRS and the second and third generation?

GPRS is developed on the basis of the second generation wireless communication system GSM, which adds network system equipment supporting packet switching in the transmission of data streams. The third generation wireless communication system will make further technical progress and development on the basis of GPRS, and fully support the high-speed and broadband multimedia data transmission of the network. In other words, GPRS is a network technology between the second generation and the third generation, generally called 2.5 generation.

How long is the life of GPRS? Is it just a transitional product?

Transition products can be regarded as phased mainstream products if they are transitioned for several years or even longer. At present, the world is cautious about the development of 3G networks, and it is believed that operators in China will develop 3G networks steadily according to the number and demand of data users. In the vacuum period of several years, GPRS is undoubtedly the first choice for the development of mobile data services.

GPRS is a packet-switched data bearing and transmission service developed on the basis of GSM system, and it is a 2.5-generation network product, but it does not mean that GPRS is only a transitional product. On the contrary, GPRS is a very important and indispensable step and milestone in the evolution from the second generation network to the third generation network. Compared with GSM, GPRS has achieved a qualitative leap from circuit switching to packet switching in data transmission, which has greatly promoted the development of mobile Internet and data services. At this stage, the road of the third generation is not very clear, and the technical development and market demand are not very mature. In the next 4-5 years, GPRS will become the most important carrier of mobile data services.

In addition, all network products and services of new technologies come from backward compatibility, that is to say, even if the third generation network already exists, GPRS will coexist with the third generation for a long time due to the network cost and gradual market.

What are the characteristics of GPRS compared with CDMA?

Strictly speaking, GPRS is a mobile data network developed on the basis of GSM network and based on 2.5 generation technology, which realizes data transmission through packet switching. The main advantages of GPRS are "always on" and "charging by flow". In other words, GPRS can surf the Internet at any time without dialing, and keep in touch with the network at any time, and the charge is more reasonable, and it is completely charged according to the actual traffic. Moreover, GPRS is developed on the basis of the original GSM in the wireless end of the network, so the network coverage of GPRS should be said to be relatively mature; In addition, the original GSM users are upgraded to GPRS users without changing their mobile phone numbers, and GPRS services are directly opened on GSM mobile phone numbers.

There are several kinds of CDMA, such as IS-95A, IS-95B and CDMA2000. IS-95B is what people usually call narrowband CDMA. It is based on 2G network technology, and the data transmission mode is the same as GSM. IS_95A(CDMA2000 1x) is the second-generation CDMA technology, while CDMA2000 is the third-generation technology. At present, most domestic operators and CDMA to be built are IS-95B, which means it is only the second generation network of CDMA.