The design and use of multi-standard RF transceivers is the way to increase hardware flexibility and functionality, as well as to improve the flexibility of set-makers on the market. In the design of multi-standard RF transceivers the efforts will be directed towards improvement of hardware reusability, reconfigurability, programmability and flexibility. This will result in the launching of a software-defined radio. Since the radio environment is variable, the application of adaptivity in RF transceivers results in the reduction of their power consumption. Eventually, it is reasonable to believe that RF front-ends will be smart in the sense that they will be able to monitor the radio environment and to adapt themselves to the changes in this environment paving the way for a cognitive radio.