root@OpenWrt:/etc/config# cat wireless 

config wifi-device 'radio0'
	option type 'mac80211'
	option channel '11'
	option macaddr '74:ea:3a:a2:bc:80'
	option hwmode '11ng'
	list ht_capab 'SHORT-GI-40'
	list ht_capab 'DSSS_CCK-40'
	option txpower '20'
	option country 'FR'
	option htmode 'HT40-'
	option distance '10'

config wifi-iface
	option device 'radio0'
	option network 'lan'
	option mode 'ap'
	option ssid 'xxx'
	option key 'yyy'
	option encryption 'psk2+ccmp'
	option wpa_group_rekey '0'
# important : WPA GROUP REKEY, aka Renewal, is the period at which the WPA key is regenerated from the key-phrase. Even for PSK !
# WPA Group Cipher rekeying interval in seconds
# With this set to default (600sec), some devices are lost eg: Sagem myRadio 700
# with 0, it doesn't rekey
# corresponds to "Group Key Update Period" for TPLINK original firmware
# @see https://forum.openwrt.org/viewtopic.php?pid=215126