title: How to calculate wifi dynamic frequency selection probability
body: <p>I have no idea how I can handle this question. </p>
  
  <p>Let's say 802.11h AP points are spread out throughout a street. </p>
  
  <pre><code>#52, #56 ...., #140
  </code></pre>
  
  <p>A bus that is connected to #52 channel is travelling along that street with a constant speed.</p>
  
  <p>What's probability that that bus will have to change its AP?</p>
  
  <p>Thanks.</p>