Problem description:
Multi-angle and multi-faceted analysis, there will be bonus points for answering well.
Analysis:
GSM is a European standard, which is widely used all over the world. It is the first generation of digital machines. The second generation includes GPRS (upgraded version of GSM) and CDMA. But by the third generation, it was basically unified with CDMA platform. CDMA is a patented product in Qualcomm, USA, and it is Microsoft and Intel in the mobile phone industry. The International Telecommunication Union has determined that the third generation technology will be based on CDMA. GSM has WCDMA, CDMA has CDMA2000, and there is a Datang TDSCDMA in China, but it is also necessary to pay patent fees to Qualcomm in essence. Nokia, Motorola and other giants also jointly sued Qualcomm, accusing Qualcomm of charging exorbitant patent fees. Therefore, in the third generation, China still cannot outshine others, and needs complete independence. At present, countries that use CDMA include the United States, South Korea, Japan, Hong Kong and Vietnam. CDMA technology is slightly ahead of other technologies, and can achieve better results with less investment, but the problem is that technology monopoly is more important in Europe than GSM.
In addition, from the analysis of mobile phone network in China, the coverage of mobile network, namely GSM network, is much higher than that of CDMA network, so G network is better than C network relative to mobile phone signals. However, it should be noted that the network of C network is the best, because the radiation is extremely small. Under the same circumstances, the radiation size of G network mobile phone is dozens of times that of C network; Moreover, because C network has been used in the military field, its safety factor is better than G network.