Access facebook over USSD
There are many value added services (VAS) can be offered using USSD. Facebook over USSD is one of them. Why we need this over USSD? The answer lies in the main feature of USSD. USSD sends user types strings or text from mobile device to the home network or to a USSD gateway and vice versa. It does not require an internet connection or a smart phone. This is mainly used in countries where people have lesser number of smart phones and a mobile operator wants to open new channels for the revenue.
The main issue with USSD is that it limits the number of characters over GSM network. So for long text , VAS provider do many message transaction to get the string.
VAS application for facebook:
The fist thing for providing service, a VAS provide deploys a ussd application over a server. Server connects to the mobile network over SS7 protocol to interact with the mobile user and connects to the internet for facebook access. A short code is assigned to the application. So that if a subscriber dials short code, USSD call reaches to the server and a session is started.
Call flow for facebook over USSD:
Mobile user dials the string (e.g *456#) for accessing facebook.
String reaches to the application.
Application cheeks for subscription. If mobile user subscribed for service, ussd application displays the menu to the handset , which asks for facebook use name and password.
After getting a user name and password, application calls the authentication API of facebook to get the token.
Once token is generated, application displays the facebook options (e.g post on a wall, like etc.) to the subscriber.
Subscriber chooses the option and application calls the corresponding facebook API for the action and returns the result to the handset.
On logout service provider deletes the access token for facebook.