Monthly 2026, 05 - WiFi vs Mobile Network

During a stint of working at a company I was certain I was going to leave relatively quickly, I noticed that my phone's battery drains a lot faster when on cellular network than when on WiFi. I've since found the data-saver setting on my phone which slightly mitigates the problem and isn't a problem when I'm not actively looking for work, but since then I've noticed that I don't actually know how WiFi and cell networks differ in technology. As someone who is tethered to either one of them at most moments in time, I feel I really should be aware of that, so this is me getting a rough overview of the technologies as they exist in 2026.

I'm already familiar with frequency bands and the physics that makes gives one an advantage over another, as well as the differences in IEEE standards that have more recently given way to the "WiFi X" labeling.

WiFi basically facilitates a wireless connection between access points (AP) and stations (STA), wherein access points provide a (central) node in a network, and the STAs connect to the network through the AP. The full unit of connected STA to an AP is an Infrastructure Basic Service Set (BSS), which comes with an ID (SSID). It in turn can be extended using the AP MAC Address or BSSID. STAs usually scan their environments with passive scans wherein they listens on a list of typical frequencies. Active scanning would involve the STA sending probe requests for available APs. In a directed probe request, the SSID is sent along with the request. Once a network has been identified, the STA sends an authentication request and waits for the AP's response, the details of which depend on the security protocol. The actual connection is made through the association request and a handshake. WiFi uses unicast, multicast and broadcast traffic, depending on the purpose of data stream. (https://academy.nordicsemi.com/courses/wi-fi-fundamentals/lessons/lesson-1-wifi-fundamentals/topic/what-is-wifi/)

Mobile broadband works through radio waves, communicated through cell towers. Looking up how 5G works results in a bunch of weird conspiracy bunk (thanks, anglosphere), so I had to do a little more digging for this one. There's roughly 2 broadband network families in use, namely the GSM family, and the WiMAX family. The radio network layer of LTE splits into a control plane and a user plane, in which the data packets are assembled for the communication protocols (TCP/UDP/IP). The control plane handles the actual connection via radio resource control (RRC). From the user plane, the packets are passed through the relays to the connected LTE client. (https://www.tutorialspoint.com/lte/lte_radio_protocol_architecture.htm)

This, so far is nice to know, but it doesn't really help me solve my question: Why does my phone battery drain so much faster on LTE than on WiFi?

One factor is probably the ways I use it, which is something I find difficult to control for. Obviously I use the phone much more when I'm on the go, partly because I do a lot of work on my phone. A bunch of typing, the terrible, terrible messaging stuff, a good amount of my reading. I don't really use it all that much at home, other than to check off tasks, because most of the things I can do on a phone I can do better at a workstation with a keyboard and a decently sized screen. However, I've noticed it getting very warm in my pocket simply when traveling, or when in a building with middling to poor connection. My hypothesis at that point has to be that there is some fundamental difference in the process of polling between LTE and WiFi, or that it's a hardware difference. Both WiFi and mobile network poll the network effectively all the time, which is how we get the signal strength indicator, but they use different antennas. They act on different wavelengths: the WiFi antenna on the Wifi-bands it supports, and the cell antenna on frequencies below. Because the cell signal will have to transmit back for polling (or rather, to receive the signal in the first place), it will have to throw that lower-frequency signal over much longer distances, until it reaches the cell tower. I think that's probably a big factor in the battery drain. The worse the signal is, the more energy is required to transfer data packets to the network, so that might explain why this seems liable to happen, whenever I'm on long train journeys or in offices with poor cell connection.