Apart from serving basic communication to users, reach of wireless networks to users has been facilitating various applications and mechanisms which can add on multiple functionality of networks. Received signal strength Indicator (RSSI)/ Channel state Information (CSI) is one such statistics available on user device, which can be used to achieve multiple adjuncts network functionalities and few applications. This paper focuses mainly on RSSI based Human activity recognition (HAR), Node identification as applications and Physical layer key generation (PLKG) as security mechanism. HAR utilizes variations in RSSI values to detect presence of human or their activities. Similarly in node identification, on the basis of RSSI and environment between Access point and nodes, access point predicts the node location. Further, one of the emerging research areas PLKG, also uses RSSI preprocessing to achieve better network performance. The paper also presents comprehensive survey on hardware cards installed in user devices and software tools used to quantify RSSI in HAR applications.