Hi Farzan,
there is no SNMP agent on the APs. To monitor APs you need to query the controller, take a look into the WLSX-WLAN-MIB, specifically the wlanAPxxxxxxx OIDs, there are various ones there that can be used to view total or 'data' only components of AP, per SSID.
WLSX-WLAN-MIB::wlanAPRxDataPkts[STRING: 0:24:6c:ca:24:78][1][STRING: 0:24:6c:22:47:88] = Counter32: 0
WLSX-WLAN-MIB::wlanAPRxDataPkts[STRING: 0:24:6c:ca:24:78][1][STRING: 0:24:6c:22:47:8a] = Counter32: 3238076
WLSX-WLAN-MIB::wlanAPRxDataBytes[STRING: 0:24:6c:ca:24:78][1][STRING: 0:24:6c:22:47:88] = Counter32: 0
WLSX-WLAN-MIB::wlanAPRxDataBytes[STRING: 0:24:6c:ca:24:78][1][STRING: 0:24:6c:22:47:8a] = Counter32: 471332178
WLSX-WLAN-MIB::wlanAPTxDataPkts[STRING: 0:24:6c:ca:24:78][1][STRING: 0:24:6c:22:47:88] = Counter32: 0
WLSX-WLAN-MIB::wlanAPTxDataPkts[STRING: 0:24:6c:ca:24:78][1][STRING: 0:24:6c:22:47:8a] = Counter32: 7273404
WLSX-WLAN-MIB::wlanAPTxDataBytes[STRING: 0:24:6c:ca:24:78][1][STRING: 0:24:6c:22:47:88] = Counter32: 0
WLSX-WLAN-MIB::wlanAPTxDataBytes[STRING: 0:24:6c:ca:24:78][1][STRING: 0:24:6c:22:47:8a] = Counter32: 4261269375
regards
-jeff