6 Replies Latest reply on Mar 5, 2018 4:29 AM by swli_3187821

    Does someone know about wifi roaming on cyw43455?

    swli_3187821

      I am trying wifi roaming function on cyw43455 based on Android OS.

      I can only access the dhd driver source code, so I don't know how this feature implemented in chip firmware.

      I found that there are some values related to roaming can be set by user through dhd driver and wl tool, but I don't know the meaning of these values.

      So could someone can help to explain the meaning of these values and how they works to me in detail.

      Thank you.

       

      Here are the roaming related values in  dhd drivers:

      dhd_conf_read_roam_params: roam_off = 0
      dhd_conf_read_roam_params: roam_trigger = -65
      dhd_conf_read_roam_params: roam_scan_period = 10
      dhd_conf_read_roam_params: roam_delta = 15
      dhd_conf_read_roam_params: fullroamperiod = 120

       

      Here are the values can be set by wl tool:

      roam_channels_in_cache
      Get a list of channels in roam cache

      roam_channels_in_hotlist
      Get a list of channels in roam hot channel list

       

      roam_prof
      get/set roaming profiles (need to specify band)
      Usage: wl roam_prof_2g a|b|2g|5g flags rssi_upper rssi_lower delta, boost_thresh boot_delta nfscan fullperiod initperiod backoff maxperiod

       

      wnm_bsstrans_roamthrottle
      Get/Set number of roam scans allowed in throttle period
      Usage: wl wnm_bsstrans_roamthrottle [throttle_period] [scans_allowed]

       

      pfn_roam_alert_thresh
      Get/Set PFN and roam alert threshold
      Usage: wl pfn_roam_alert_thresh [pfn_alert_thresh] [roam_alert_thresh]

        • 1. Re: Does someone know about wifi roaming on cyw43455?
          ZhengbaoZ_96

          Hi Jevon:

           

          dhd_conf_read_roam_params: roam_off = 0

          // roam_off :   0 means  roaming function enabled.

           

          dhd_conf_read_roam_params: roam_trigger = -65

          // trigger =-65 means  if the current connected AP rssi is below -65,  the device will start roaming function

           

          dhd_conf_read_roam_params: roam_scan_period = 10

          //  scan the AP info on the channel every 10s  which is resulted in the previous scan results.

           

          dhd_conf_read_roam_params: roam_delta = 15

          //  if trigger is -65,   when rssi = -50 dbm,  the sta will start the roam.

           

          dhd_conf_read_roam_params: fullroamperiod = 120

          //  if in scan_period sta failed to find useful AP,  starts a full channel scan, the period is 120.

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          • 2. Re: Does someone know about wifi roaming on cyw43455?
            swli_3187821

            Hi zhez,

             

            Thank you for your explanation,It's really helpful to me.

             

            But I am still a little confusing about the roam_trigger and roam_delta.

            What's the difference between this two values while you said both their function is to start roaming?

            And what's the concrete operation when the rssi decreased to roam_trigger and roam_delta? starting a scan request and try to match the AP with same SSID but with different BSSID in scan results, and then try to associate with matched AP with better signal quality?

             

            Thank you for your help. Hoping to see your reply again.

            • 3. Re: Does someone know about wifi roaming on cyw43455?
              ZhengbaoZ_96

              Hi Jevon:

               

                   if roam_trigger  = -65, means If the device connected with a SSID named “test” on Channel 11 moves to a weak signal area, the device will start roam act like scanning  a better “test” AP on Channel 6  .   roam_delta = 15 ,  means if the device finds one “test ” AP and the signal is better than -50  it will roam to this “test”  AP.  

               

              Actually I didn't set up a roaming network before , but from below case you should find it needs to have same SSID,   DHCP needs to be set up accordingly , channel needs to be different for reducing the interference.

              and our roaming function is default enabled.

              • First Router
                • 192.168.1.1
                • DHCP to use the range 192.168.1.3-192.168.1.254
                • A wireless channel like 11
              • Second Router
                • 192.168.1.2
                • DHCP is disabled
                • Identical wireless security setup as First Router
                  • Except the wireless Channel. Try channel 6 if the first is 11.
                • Plug hard-wire into the LAN port, not the WAN port.
              • 4. Re: Does someone know about wifi roaming on cyw43455?
                swli_3187821

                Hi zhez,

                 

                Thank you very much.

                 

                Another question which is not quite important, but I'd like to ask: Do you know about the wl commands related to roam?

                 

                roam_channels_in_cache
                roam_channels_in_hotlist

                roam_prof

                wnm_bsstrans_roamthrottle

                pfn_roam_alert_thresh

                • 5. Re: Does someone know about wifi roaming on cyw43455?
                  ZhengbaoZ_96

                  Hi Jevon:

                   

                      We usually just to set “wl roam_off 1" to close Roaming function when doing RF test .

                  I didn't use the commands you mentioned in last message .

                  • 6. Re: Does someone know about wifi roaming on cyw43455?
                    swli_3187821

                    Hi zhez,

                     

                    OK. Thank you very much. Your reply helps me a lot.

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