Mobile Internet (5)-2.5-Generation Mobile Communication

The 2.5 generation is a technology between the second generation and the third generation .? GPRS (Universal grouping wireless service) is called in the industry? 2.5 generations .? GPRS solves the bandwidth bottleneck of mobile Internet access and is implemented on the basis of the existing mobile communication network. Do you need to discard the existing bandwidth? The GSM network is "new", so it is recognized as directed? 3G transition is a reasonable solution .? GPRS combines multiple channels to increase the bandwidth of data transmission and enables many users to share channel resources through group switching. Therefore, in theory ,? What is the transmission rate of GPRS? 170 kbps, much higher than fixed-line Internet access? 56 kbps, but the current speed is generally due to network configuration and mobile phone reasons? 20 -? 30? Kbps.

Color: Black "> CDMA 1X and GPRS belong to the same GB mobile communication network, which is mainly set up to provide grouped data services. The upgraded version 1x of CDMA 1X to 3g has been accepted by ITU as an international standard. evdo is a wireless technology designed completely for grouped data services, the peak rate within a 2.4 MHz bandwidth is Mbit/s, which has reached the ITU's three-generation system rate requirements. When evdo technology is used, the group data service still uses the group domain devices (pdsn and PCF) for processing, and no more network units need to be added. Because evdo is involved in RF and CDMA
1x/is-95 is identical, so you only need to update the corresponding channel board in the original CDMA 1X base station and then upgrade the software.

MSO; MSO-bidi-font-family: "Times New Roman MSO-ANSI-language: En-US> In the grouped data service, all mobile users share wireless resources, in addition, each user dynamically applies for and occupies wireless resources only when transmitting business data. Therefore, the grouped data method can be used to "always online" Times New Roman MSO-Fareast-language: en-CN> ". For example, if the peak rate of GPRS is 115.2 kbit/s and the peak rate of CDMA 1X is 153.6 kbit/s, the grouped data service is more suitable for mobile Internet businesses. On the other hand, because multiple mobile users share certain wireless resources under the grouping service, even though the grouping service can have a high peak business rate, however, the average service rate during data transmission is still low, and the ratio of the average service rate to the peak service rate is also an important indicator to measure system technology. From the reality, the average service rate of GPRS can reach 20 kbit/s-40kbit/s, the average service rate of CDMA 1X is 70 kbit/s-80kbit/s. In comparison, the CDMA 2000 1x technology is more efficient than the GPRS technology.