4 Replies Latest reply on Nov 24, 2016 12:00 AM by srinathl_56

    bcm20736 scan

    chenlei_198

      Hi all,

       

      I have question for BLE scan. if send a SCAN request to BLE, how long it will get a SCAN response.

      almost I found take 1 second to get a response, is it normal?

       

      Thanks,

      Lei

        • 1. Re: bcm20736 scan
          BoonT_56

          In theory, the scan response to a scan request would almost be instantaneous. The T_IFS (time_inter-frame-spae) is in the order of micro-seconds. However, the actual user-feel response could be much longer than that due to things like RF environment. A total turn around of 1s is not too bad if you ask me.

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          • 2. Re: bcm20736 scan
            chenlei_198

            Thanks for your reply.

            our application scan 70ms as master, but most of time we saw the resposne time will take 1s, is the resposne time related with the scan time?

            • 3. Re: bcm20736 scan
              BoonT_56

              I don't see how. The scan window of 70ms is many times that of T_IFS. In fact, many scan requests/response events can happen during this window.

              • 4. Re: bcm20736 scan
                srinathl_56

                How are you measuring the 1-second delay time ? I suppose you measured the time taken between starting the scan and receiving the scan response, is this right ? In the link layer, the scan response is received after T_IFS but I suppose it will take some time for the event to reach the application level.

                The best way to find out the exact time difference between the scan request and scan response is to sniff the packets over the air.

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