WiFi and Wireless
Learn how WiFi works, what the standards and frequency bands mean, how wireless security differs between WEP, WPA2 and WPA3, and why WiFi is sometimes slow.
How WiFi works
WiFi is a wireless version of an Ethernet link. Your phone and your router exchange data using radio waves, in the same family as the signals used by FM radio and mobile phones, but at higher frequencies and with a short range.
The router has an access point built in. It broadcasts a network name (the SSID), and devices join it. Once connected, your data is turned into radio signals, sent through the air, and turned back into data at the other end.
The important detail is that the air is shared. Only one device on a channel can transmit at a time, so every device and every nearby network that uses the same channel takes a share of the available time. That is why WiFi gets slower when many devices are busy.
WiFi standards: the 802.11 family
WiFi has been improved many times. The generations carry a technical name and a simpler number:
- WiFi 4 (802.11n): older, still common
- WiFi 5 (802.11ac): fast, works on 5 GHz
- WiFi 6 (802.11ax): faster, and better when many devices are connected at once
- WiFi 6E and WiFi 7: newer, with support for the 6 GHz band and even higher speeds
The speed printed on a router box is a theoretical maximum. Real speeds are lower, because walls, distance and other devices all reduce them.
2.4 GHz and 5 GHz
WiFi uses radio bands. The two main ones behave differently:
- 2.4 GHz has a longer range and passes through walls better, but it is slower and more crowded. Microwave ovens, baby monitors, Bluetooth devices and neighbouring networks use it too.
- 5 GHz is faster and less crowded, but its range is shorter and walls block it more.
Use 5 GHz when you are close to the router, and 2.4 GHz for distant rooms and for simple devices such as smart bulbs. Most routers can offer both bands under one name and let the device choose.
Channels
Each band is divided into channels. If your router and your neighbours' routers use the same channel, they have to share its airtime, and everyone slows down.
On 2.4 GHz the channels overlap, and only 1, 6 and 11 do not overlap with each other (in most regions). That is why routers normally choose one of those three. On 5 GHz there are many more separate channels, so interference is less common.
Most routers have an "auto" channel setting that works well. If your WiFi is slow in a building full of networks, try setting a channel by hand or switch to 5 GHz.
WiFi security
Anyone nearby can pick up wireless signals, so the data has to be encrypted. These are the security modes you will see:
- Open: no password and no encryption. Anyone can read your traffic.
- WEP: very old and broken. It can be cracked within minutes. Never use it.
- WPA2: the long-time standard. It is secure with a strong password.
- WPA3: the newest and strongest, with better protection against password guessing.
For home use, choose WPA2 or WPA3 with a long, unique passphrase. Four or five random words work well.
SSID: the network name
The SSID (Service Set Identifier) is the name shown in your list of WiFi networks. Two good habits:
- Do not put your name or address in it.
- Be careful with lookalike networks. An attacker can create one named "Free_Airport_WiFi" to attract connections.
Hiding the SSID does not improve security. The name is still sent when devices connect, and tools can find it easily.
Bigger homes: extenders and mesh
One router may not cover a large house. The usual options are:
- An extra access point: a second device connected to the router by cable. This gives the best speed.
- A mesh system: several units that work together as one network. Your phone moves between them as you walk around.
- A range extender: repeats the signal wirelessly. It is cheap, but it often cuts speed roughly in half, because it receives and retransmits on the same airtime.
When possible, connect access points with cable. Wireless links between them use airtime that your devices also need.
Why is my WiFi slow
Work through the usual causes:
- Distance and walls. Move closer, or place the router in a central, open spot.
- Interference. Too many networks on the same channel. Change the channel or use 5 GHz.
- Too many devices. Streaming, downloads and updates all share the same airtime.
- Old equipment. An old WiFi 4 router limits what a modern phone can reach.
- The internet plan itself. Test with a cable. If the wired connection is also slow, WiFi is not the problem.