首先，WiFi，WiFi（Wireless Fidelity）技术是基于IEEE 802.11系列标准的无线网络通信技术的品牌。与蓝牙技术一样，它属于短程无线技术。该技术目前使用2.4 GHz和5 GHz左右的频段。
The transmission power of most wireless routers is between 50mW and 100mW. The router WiFi realizes short-range wireless network communication.
The following describes the 4G network. Here, "G" refers to "Generation", and 4G refers to the fourth generation communication technology.
History of evolution from 1G to 5G
The current mainstream mobile communication standard 4G LTE theory has a maximum bandwidth of 150 Mbps. LTE-A (also known as LTE-Advanced) is an enhanced version of LTE that uses carrier aggregation technology and peak speeds of up to 1000 Mbps.
If you want to maintain a stable and fast 4G network connection, you must perform frequent uplink and downlink signal flow between the mobile phone and the base station. At this time, the transmission power of the mobile phone is generally between 100mW and 1000mW. When the signal state is good, the normal use is about 100mW to 200mW.
4G signal strength
But when the signal is not very good, the mobile phone has to transmit a more powerful signal to search the network. At this time, the mobile phone's transmission power tends to be larger, so it will increase the power consumption.
Usually the base station will be built at a high level to ensure coverage efficiency, as shown in the figure below.
Since the base station antenna is a directional transmission signal method, in order to ensure sufficient coverage, generally a group of arrays usually consists of three antennas. In this way, a 4G base station typically covers a range of 1-3 kilometers. It can be seen that the coverage of the 4G base station is much larger than that of the WiFi signal.
In addition, for the question given by the title, Apple also gave an official battery life data.
Here LTE refers to 4Gxx在这种情况下，使用WiFi比使用4G电池寿命更长。