title: LE Connection CTE Request Enable unclear when CTE_Request_Interval is set to non-zero
body: <p>This question rises from the Madrid r13 spec regarding the "LE Connection CTE Request Enable" command.</p>
  
  <p>Some background about CTE_Request_Interval:
  When CTE_Request_Interval is configured, a Controller which has an active "LE Connection CTE Request Enable" will transmit a LL_CTE_REQ every X Connection Intervals (which will be answered by a LL_CTE_RSP containing a CTE).</p>
  
  <p>What I am trying to understand is: When is a "LE Connection CTE Request Enable" command still active.</p>
  
  <p>From the spec:
  "A request is active on a connection from when the Host issues a successful
  command with Enable set to 0x01 until the single procedure has been
  performed, the period specified by CTE_Request_Interval has ended, or a
  command with Enable set to 0x00 has succeeded, whichever happens first".</p>
  
  <p>From what I understand, a command ends when either:</p>
  
  <ul>
  <li>CTE_Request_Interval is not set, which means that LL_CTE_REQ will be transmitted and answered only once by a LL_CTE_RSP and the request will not be active any longer</li>
  <li><p>The host has disabled CTE (doesn't matter if CTE_Request_Interval was active as all other params are ignored when enable is set to 0)</p></li>
  <li><p><strong>Now the third case is what I'm having trouble with. The spec says:
  "the period specified by CTE_Request_Interval has ended"</strong></p></li>
  </ul>
  
  <p>What does this mean? </p>
  
  <ul>
  <li>From what I figure, CTE_Request_Interval happens periodically, so why would the request stop being active? </li>
  <li>Maybe the spec means that the request is no longer active until the next period? Does this make any difference from an implementation perspective, or is it just semantics?</li>
  </ul>
  
  <p>Thanks,
  Maxim</p>