We know all the solution to use a gateway to send a SMS. THis is the premium way. Those company make a deal with the operators and those operators sell them SMS.
There are another way, called low cost solution. This is a not priority way, a route where the deliverability is not assured but the cost is the cheapest possible!
We need to meet someone who now thsi technology. We will hire him to build this solution. For now we are looking for a consultant.
Please bid ONLY if you are expert on this domain.