RECOMMENDATION ITU-R M.1455 - KEY CHARACTERISTICS FOR THE INTERNATIONAL MOBILE TELECOMMUNICATIONS-2000 (IMT-2000) RADIO ... 1 Introduction 2 Scope 3 Related Recommendations 4 Considerations 4.1 The RTT evaluation process 4.2 Consensus building 4.3 Impact of evolution on the development of the key characteristics for IMT-2000 4.4 Impact of modularity 4.5 High level descriptions 4.6 Generic IMT-2000 radio interface description 4.7 Further steps in the IMT-2000 radio interface development process 5 Recommendations 5.1 Terrestrial 5.2 Satellite ANNEX 1