Dell Inspiron 15R - limited connectivity on wifi

Wireless Band: 2.4GHz Band

Enable Wireless:   Always   

Wireless Network Name: (Also called the SSID)

802.11 Mode:  802.11b only                   802.11g only   802.11n only   Mixed 802.11g and 802.11b                   Mixed 802.11n and 802.11g   Mixed 802.11n, 802.11g and 802.11b  

Enable Auto Channel Scan:

Wireless Channel:  2.412 GHz - CH 1   2.417 GHz - CH 2   2.422 GHz - CH 3   2.427 GHz - CH 4   2.432 GHz - CH 5   2.437 GHz - CH 6   2.442 GHz - CH 7   2.447 GHz - CH 8   2.452 GHz - CH 9   2.457 GHz - CH 10   2.462 GHz - CH 11   2.467 GHz - CH 12   2.472 GHz - CH 13  

Transmission Rate:  Best (automatic)   (Mbit/s)

Channel Width:  20 MHz   20/40 MHz(Auto)  

Visibility Status: Visible  Invisible

WPA-personal

WPA mode: Auto

any idea why this issue is occurring. the limited connectivity issue is occurring like 90% of the time. Sometime I successfully connected and the connection is good, but while using it, it suddenly drops and turns into limited connectivity. 

first time posting. appreciate the helps