Thank you for your reply Jose ,
I have configure bmiss parameter in rc.conf as you said and enable
debug.iwi in sysctl , Bellow you can see the log entries.
Jun 29 13:40:13 bsdt43 kernel: enter FW state 4
Jun 29 13:40:13 bsdt43 kernel: Scan request: index 393 dwell 150/30/30
Jun 29 13:40:13 bsdt43 kernel: Scan 1 2.4GHz channels: 1/BCAST
Jun 29 13:40:13 bsdt43 kernel: sending command idx=13 type=26 len=96
Jun 29 13:40:13 bsdt43 kernel: sending command idx=14 type=23 len=0
Jun 29 13:40:13 bsdt43 kernel: Scan completed (1, 2)
Jun 29 13:40:13 bsdt43 kernel: exit FW state 4
Jun 29 13:40:43 bsdt43 kernel: enter FW state 4
Jun 29 13:40:43 bsdt43 kernel: Scan request: index 394 dwell 150/30/30
Jun 29 13:40:43 bsdt43 kernel: Scan 1 2.4GHz channels: 6/BCAST
Jun 29 13:40:43 bsdt43 kernel: sending command idx=15 type=26 len=96
Jun 29 13:40:44 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:40:44 bsdt43 kernel: exit FW state 4
Jun 29 13:40:44 bsdt43 kernel: enter FW state 4
Jun 29 13:40:44 bsdt43 kernel: Scan request: index 395 dwell 108/30/30
Jun 29 13:40:44 bsdt43 kernel: Scan 1 2.4GHz channels: 11/BCAST
Jun 29 13:40:44 bsdt43 kernel: sending command idx=0 type=26 len=96
Jun 29 13:40:44 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:40:44 bsdt43 kernel: exit FW state 4
Jun 29 13:40:44 bsdt43 kernel: enter FW state 4
Jun 29 13:40:44 bsdt43 kernel: Scan request: index 396 dwell 50/30/30
Jun 29 13:40:44 bsdt43 kernel: Scan 1 2.4GHz channels: 7/BCAST
Jun 29 13:40:44 bsdt43 kernel: sending command idx=1 type=26 len=96
Jun 29 13:40:44 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:40:44 bsdt43 kernel: exit FW state 4
Jun 29 13:40:59 bsdt43 kernel: enter FW state 4
Jun 29 13:40:59 bsdt43 kernel: Scan request: index 397 dwell 149/30/30
Jun 29 13:40:59 bsdt43 kernel: Scan 1 2.4GHz channels: 13/BCAST
Jun 29 13:40:59 bsdt43 kernel: sending command idx=2 type=26 len=96
Jun 29 13:40:59 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:40:59 bsdt43 kernel: exit FW state 4
Jun 29 13:40:59 bsdt43 kernel: enter FW state 4
Jun 29 13:40:59 bsdt43 kernel: Scan request: index 398 dwell 91/30/30
Jun 29 13:40:59 bsdt43 kernel: Scan 1 2.4GHz channels: 2/BCAST
Jun 29 13:40:59 bsdt43 kernel: sending command idx=3 type=26 len=96
Jun 29 13:40:59 bsdt43 kernel: sending command idx=4 type=23 len=0
Jun 29 13:40:59 bsdt43 kernel: Scan completed (1, 2)
Jun 29 13:40:59 bsdt43 kernel: exit FW state 4
Jun 29 13:41:09 bsdt43 kernel: enter FW state 4
Jun 29 13:41:09 bsdt43 kernel: Scan request: index 399 dwell 150/30/30
Jun 29 13:41:09 bsdt43 kernel: Scan 1 2.4GHz channels: 3/BCAST
Jun 29 13:41:09 bsdt43 kernel: sending command idx=5 type=26 len=96
Jun 29 13:41:09 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:41:09 bsdt43 kernel: exit FW state 4
Jun 29 13:41:09 bsdt43 kernel: enter FW state 4
Jun 29 13:41:09 bsdt43 kernel: Scan request: index 400 dwell 91/30/30
Jun 29 13:41:09 bsdt43 kernel: Scan 1 2.4GHz channels: 4/BCAST
Jun 29 13:41:09 bsdt43 kernel: sending command idx=6 type=26 len=96
Jun 29 13:41:09 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:41:09 bsdt43 kernel: exit FW state 4
Jun 29 13:41:09 bsdt43 kernel: enter FW state 4
Jun 29 13:41:09 bsdt43 kernel: Scan request: index 401 dwell 33/30/30
Jun 29 13:41:09 bsdt43 kernel: Scan 1 2.4GHz channels: 5/BCAST
Jun 29 13:41:09 bsdt43 kernel: sending command idx=7 type=26 len=96
Jun 29 13:41:09 bsdt43 kernel: sending command idx=8 type=23 len=0
Jun 29 13:41:09 bsdt43 kernel: Scan completed (1, 2)
Jun 29 13:41:09 bsdt43 kernel: exit FW state 4
Jun 29 13:41:19 bsdt43 kernel: enter FW state 4
Jun 29 13:41:19 bsdt43 kernel: Scan request: index 402 dwell 150/30/30
Jun 29 13:41:19 bsdt43 kernel: Scan 1 2.4GHz channels: 8/BCAST
Jun 29 13:41:19 bsdt43 kernel: sending command idx=9 type=26 len=96
Jun 29 13:41:19 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:41:19 bsdt43 kernel: exit FW state 4
Jun 29 13:41:19 bsdt43 kernel: enter FW state 4
Jun 29 13:41:19 bsdt43 kernel: Scan request: index 403 dwell 106/30/30
Jun 29 13:41:19 bsdt43 kernel: Scan 1 2.4GHz channels: 9/BCAST
Jun 29 13:41:19 bsdt43 kernel: sending command idx=10 type=26 len=96
Jun 29 13:41:19 bsdt43 kernel: sending command idx=11 type=23 len=0
Jun 29 13:41:19 bsdt43 kernel: Scan completed (1, 2)
Jun 29 13:41:19 bsdt43 kernel: exit FW state 4
Jun 29 13:41:40 bsdt43 kernel: enter FW state 4
Jun 29 13:41:40 bsdt43 kernel: Scan request: index 404 dwell 150/30/30
Jun 29 13:41:40 bsdt43 kernel: Scan 1 2.4GHz channels: 10/BCAST
Jun 29 13:41:40 bsdt43 kernel: sending command idx=12 type=26 len=96
Jun 29 13:41:40 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:41:40 bsdt43 kernel: exit FW state 4
Jun 29 13:41:40 bsdt43 kernel: enter FW state 4
Jun 29 13:41:40 bsdt43 kernel: Scan request: index 405 dwell 111/30/30
Jun 29 13:41:40 bsdt43 kernel: Scan 1 2.4GHz channels: 12/BCAST
Jun 29 13:41:40 bsdt43 kernel: sending command idx=13 type=26 len=96
Jun 29 13:41:40 bsdt43 kernel: Scan completed (1, 1)
Jun 29 13:41:40 bsdt43 kernel: exit FW state 4
Jun 29