Wi-Fi Signal gets slower
Why the Wi-Fi signal gets slower with distance from the access point
The wireless network is, well, wireless. It uses radios to send and receive data. As one moves further from the transmitter, the signal diminishes in intensity or attenuates. Additionally, the electrical radio-frequency noise found in any office or home impacts the signal. That means that the signal-to-noise ratio at the receiver decreases with distance. Combined, these mean that the farther one is from the access point, the more difficult it is for the receiver to decode the data.
The 802.11 standards have a way to deal with that. As the AP ( access point) detects a receiver with a weaker signal, it reduces the data rate, minimizing the effects of attenuation (actually free space path loss) and noise. At some distance, the signal will be too weak for data transfer. We discuss this, along with more details of Wi-Fi operation in Learning Tree’s Course 450 Introduction to Networking.
Getting a stronger signal
The goal of a range extender is to receive the data from the access point and to resend it to the mobile device, then to receive the data from the mobile device and relay it to the AP. Then the AP thinks it’s close to the device and can use a higher data rate.
That sounds good except for the kicker: many inexpensive range extenders only have a single radio. That means they can send or receive only on a single channel. So when they resend the AP data to the remote client, they are using the same channel the AP is! That means the channel is twice as busy as before. The busier channel reduces the overall throughput on the channel leading to an effective reduction the user experience.
A better range extender
More expensive range extenders have two or more radios. That means that they can receive on, say, channel 1 and resend to the mobile device on channel 6. This is a much better solution for small networks. It means the signals won’t interfere and the data rate can still be high. But as larger networks move to access points using three channels simultaneously, the range extender becomes impractical. It’s still great for a home or small office, but not a solution for larger installations.
An additional access point is even better
Adding an additional access point is an even better solution. It can have multiple radios or not based on need. It can use a separate channel than the initial access point. In a more complex environment, one can even take advantage of “tri-band” devices.
The downside of adding an additional AP is that it requires a network connection. This can be Ethernet, or in a home or small office, it can be connected using data over the powerlines. I use the latter. In some installations, additional access points are powered over the network cable using power over Ethernet, so a connection to wall current isn’t necessary.
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