mum capacity evolution and Moore's law also help in this commonality between FDD and TDD solutions are problem. New techniques are enabled by the higher pronounced. processing power in the devices - techniques that deliver During the fall 2005, 3GPP TSG RAN WG1 made ex- more bits of data per hertz. Furthermore, the coverage is tensive studies of different basic physical layer technologies increased with more advanced antennas and receivers. and in December the TSG RAN plenary decided that the This enables the operators to deliver the services to more LTE radio access should be based on OFDM in the down- users from one base station, thus requiring fewer sites. link and single carrier FDMA in the uplink. Fewer sites imply lower operational and capitalization At the same time as the LTE discussion was ongoing, costs. In essence, the operators need fewer base stations 3GPP TSG RAN and its WGs continued to evolve the and sites to provide the service. WCDMA system with more functionality, most notably Obviously, all services would be 'happy' if they were MBMS and Enhanced Uplink. These additions were provided with the highest data rate, lowest delay, and done in a backward compatible manner: that is, terminals lowest jitter that the system can provide. Unfortunately, of earlier releases can coexist on the same carrier in the this is unattainable in practice and contradictory to the same base station as terminals of the latest release. The operator goal of an efficient system: in other words, main argument for the backward compatibility is that the more delay a service can handle the more efficient the installed base of equipment can be upgraded to the system can be. Thus, the cost of providing lowest handle the new features while still being capable of possible delay, jitter and call setup time is somewhat in serving the old terminals. This is a cost-efficient addition conflict with the need of the mobile-network operator to of new features, albeit the new features are restricted by provide it to all the users. Hence, 