You can be an internet subscriber using corDECT but it cannot be so with the present generation of CDMA systems. CDMA has the advantage of better spectrum usage. I believe that you are talking of trunk mobile radios. This service is already available in the country. It is being used less because of higher cost and its limited usage for one way communication.
Some people always oppose whatever is developed in India because they are more fancy of imports.
Some more people oppose it because interest of importers is hurt. The fact however remains that indigenous technology will only result in cheaper price of equipment. This has been proven a number of times. However, it also need to get more efficient as few years down the road their monopoly will be gone. In today's situation in many of the matters DoT has more powers than TRAI .