The meaning of 4G terms VoLTE, CSFB, SGLTE
Answer: The full name of VoLTE is Voice over LTE (LTE call). It is an IP data transmission technology that does not require 2G/3G network. All services are carried on the 4G network, which can realize the unification of data and voice services under the same network. In addition, the call quality has been greatly improved. At present, various operators are carrying out VoLTE deployment, and full commercial use is a trend in the future. However, due to the large transformation of the entire network, it is not easy to implement.
Since the current 4G network does not implement VoLTE, the 4G network itself cannot provide the call function. There are mainly two mainstream 4G call solutions:
[1] CSFB (i.e. Circuit Switched Fallback, circuit domain fallback), that is, it falls back from the 4G network to the 3G/2G network during the call, and then switches to the 4G network after the call. In the signal bar above the phone, you will only see one 4G signal. Currently, the iPhone 6 uses this solution. The advantage is that the cost is lower, and the disadvantage is that there may be a delay of about 1 second in the middle, and the Internet access on the mobile phone will be interrupted during the call.
[2] SGLTE (i.e. Simultaneous GSM and LTE, simultaneous support of GSM network and LTE network), in layman's terms, is dual standby, or single card dual standby, an additional baseband chip is installed on the mobile phone to provide a separate 2G Internet standby, only for calls. As long as a SIM card is inserted into the mobile phone, it can work in the LTE network and 2G/3G network environment at the same time. This is the dual standby mode. The signal bar above the 4G mobile phone using this mode will see two signals. The disadvantage is that the cost is high, and the power consumption affects the battery life of the mobile phone. 4G jammer
VoLTE, on the other hand, divides a part of the bandwidth separately in the 4G LTE network, converts the voice into data, and uses this part of the bandwidth to send, so as to directly realize the call under the 4G network. It has the advantages of shorter call waiting time, better sound quality, and clearer video calls. It is better than CSFB and SGLTE, but only if the entire 4G network coverage is good, VoLTE can play an effective role, otherwise there is no 4G signal. , the phone will not be able to dial.
