Answering A Wi-Fi Question With Analogies – Analogy #2

How far can your AP reach?

Giving examples and telling stories are a few of the best techniques to send a memorable and impactful message across. Let’s try to put in simple examples, real-life analogies that would help clarify the question pitfalls and answer it.

Analogy #2: Even in a one-sided conversation, you still need a listener – STA Capabilities & Interference

Let’s get back to the simplest form of communication: speaking and listening. To prove this statement, I usually think of myself preferring to send a voice message over typing in a long text over WhatsApp, for many different reasons. Speaking and listening, in their simplest forms, require:

  • A speaker
  • A listener
  • A speaking medium (usually the air)

Limiting speaking/listening to just a pair is very simple and goes along with the core of Wi-Fi technologies traditionally being a “one-at-a-time” conversation between any two STAs (eg: AP-to-AP, AP-to-Client). A conversation or communication wouldn’t be called effective if either the speaker has failed to articulate their message clearly or the listener has failed to receive the message clearly, 2 essential aspects in maintaining the integrity of the message content.

Sending the message across and receiving it clearly could then be associated with how loud a speaker can talk/shout, and how well the listener can hear. Even if the speaker was shouting at the top of their lungs, if the listener is too far away to hear or is hard of hearing, the message wouldn’t be received. The same goes for the other side of the conversation, where the speaker and listener to switch sides.

In Wi-Fi, it’s not only how loud you can broadcast, but also how well the receiving STA can hear the signal and how powerful it is, with a client STA usually not as powerful as the AP STA, to talk back.

What about the medium? Well, imagine having the same conversation between a pair of evenly matched speaker and listener in 2 different settings: a library and a football stadium (both pre-COVID19). Controlling all the other aspects of the conversation, including the distance between the two, will yield different results of getting the message across successfully. The speaker and the listener might have to adjust a value under control, such as shouting instead of speaking, or listening better, and the communication might still fail in the case of the stadium. The message could be loud enough, or not, and the listener could be more sensitive to the noise than the message itself.

This is exactly what noise is! Interference from Wi-Fi and non-Wi-Fi signals affects the clarity of the signal at the STA side.

So why not shout louder? Not in the library you can’t. And even in the stadium, as a speaker, you would annoy the people closest to you. There are social norms and rules against such situations. Speaking of rules, on to the third analogy.

Previous: Analogy #1: Wi-Fi coverage is like bouncing a pebble across water.

Next: Analogy #3: A Prius and a Ferrari are racing on the highway, which car can speed the most?


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