Setting up your own SMS gateway is a very difficult task because you need a proper setup and your own telecom company. The overall cost for building own SMS gateway...
It is not possible to change the sender mobile number in android SMS service. There are following reasons because of which senders are not allowed to change their mobile number:
1 When a user sends SMS by using SmsManager, they encode it with a text message and mobile number in which user want to send SMS.
2 After that user encode this message with the message center number
3 Then Android platform handle its sending to the cell phone tower
4 After that message is out of user’s hands.
5 If a user tries to encode the recipient phone number as text, then SMS carrier would have no idea how to send the message.
6 Mobile phones do not have any SMS ID unless the number through which user send the message.
7 When the network carrier sending an SMS, it goes through a message center. After that message, center determines what data is forwarded to the recipient phone. Nowadays, message centers do not support what user’s wanting, they only support their protocol.
Still, if you want to change your mobile number in Android SMS service then you can change it with the help of third party SMS Gateway. For sending SMS with the help of third party gateway, you have to reroute the SMS that comes from a phone number that you register for your app.
Hope this information will help you to change your mobile number in Android SMS service