 varying complexity, cost and capabilities in order to satisfy the needs of different types of users Requirements from bodies outside SMG Alignment with IMT UTRA shall meet at least the technical requirements for submis- sion as a candidate technology for IMT 2000 (FPLMTS) Minimum bandwidth It should be possible to deploy and operate a network in a limited allocation bandwidth (e.g. 5 MHz) Electro-magnetic com- The peak and average power and envelope variations have to be patibility (EMC) such that the degree of interference caused to other equipment is not higher than in today's systems RF radiation effects UMTS shall be operative at RF emission power levels, which are in line with the recommendations related to electromagnetic ra- diation Security The UMTS radio interface should be able to accommodate at least the same level of protection as the GSM radio interface does Co-existence with other The UMTS Terrestrial Radio Access should be capable of co- systems existing with other systems within the same or neighbouring band depending on systems and regulations Multi-mode implementation capabilities It should be possible to implement dual mode UMTS/GSM ter- minals cost effectively By looking at the bearer capabilities in Table 1.2, we can see that evolution towards higher rates will initially apply mainly to indoor rates. In this environment convergence will also have higher impact. In addition, UTRA will not only prevent seamless HO between different operators or access networks, but also support HO between 2G and 3G systems, e.g. GSM and UMTS. UTRA will support key technologies, like ATM, IP, BISDN, as well as GSM, when it comes down to core network (CN) transports. This will consolidate the trend of 2G CN towards integrated circuit switched and packet switched services. ENHANCING TECHNOLOGIES 1.3.1 Capacity Increasing Antennas By increasing the number of BS antennas we can resolve the uplink limitation of WCDMA. However, this approach does not allow a single step solution because many factors intervene before 