With 3G, there are equally many evolution steps. For mobile backhaul, the most important ones are:
The above translates to (theoretical maximum) downlink peak rates for a single user so that with Rel-7, HSDPA 64 QAM reaches 21 Mbit/s. Rel-8, HSDPA 64 QAM with 2 × 2 MIMO achieves 42 Mbit/s. Rel-9, Dual-cell (2 × 5 MHz), MIMO and 64 QAM produces 84 Mbit/s. With a higher amount of carriers aggregated, the peak rate grows (four carriers 84 Mbit/s, and eight carriers potentially 168 Mbit/s). In practice, availability of terminals may limit the applicability. However, this illustrates that high peak rates are achievable with the enhanced HSPA+ networks.
Additionally, a number of improvements to existing functionalities have been included.
A simplified 3G system architecture with a UTRAN focus is shown in Figure 3.9.
Each Node B connects to an RNC (Radio Network ...