I have openwrt wireless router with me. So I have configured my router in 2.4G radio with OBSS Coexistence
enabled mode. As I searched in internet if OBSS Coexistence enabled means it will move radio from 40MHz to 2MHz bandwidth mode if there is any interference in the frequency. My neighbors are having the same 40MHz and I verified it manually with them. So to avoid interference I enable OBSS Coexistence in my opwenwrt router. But It seems my router never changing to 20MHz and I am facing some drops in my router. So how can I verify this function?
Here is my wireless config

# show config wireless

config wifi-device 'r2g'
    option type 'intel'
    option ifname 'wifi2g'
    option txpower '24'
    option hwmode '11g'
    option country 'US'
    option frameburst '1'
    option maxassoc '32'
    option obss_coex '1'
    option disabled '0'
    option cwmp_radio_instance '1'
    option channel '1'
    option htmode 'HT40'
    option autochannel '0'

config wifi-iface 'i2g'
    option device 'r2g'
    option ifname 'wifi2g'
    option network 'lan'
    option mode 'ap'
    option doth '1'
    option wmm '1'
    option wmf '1'
    option ssid 'AK-fd20'
    option key '37c19c43b0'
    option encryption 'psk2+ccmp'
    option guest '0'
    option cwmp_ssid_instance '1'
    option cwmp_access_pt_instance '1'
    option up '1'
    option hidden '1'

config wifi-iface 'i2g_guest'
    option device 'r2g'
    option ifname 'wifi2g-Guest'
    option network 'guest'
    option mode 'ap'
    option doth '1'
    option wmm '1'
    option wmf '1'
    option ssid 'AK-fd20-Guest'
    option key '37c19c43b0'
    option encryption 'psk2+ccmp'
    option guest '1'
    option disabled '1'
    option cwmp_ssid_instance '2'
    option cwmp_access_pt_instance '2'
    option up '1'

config wifi-iface 'i2g_mesh'
    option device 'r2g'
    option ifname 'wifi2g-Mesh'
    option network 'lan'
    option mode 'ap'
    option doth '1'
    option wmm '1'
    option wmf '1'
    option ssid 'AK-fd20-Mesh'
    option key '37c19c43b0'
    option encryption 'psk2+ccmp'
    option disabled '1'
    option cwmp_ssid_instance '3'
    option cwmp_access_pt_instance '3'
    option up '1'

config wifi-status 'status'
    option wps '1'
    option sched_status '0'
    option schedule '0'
    option wlan '1'