LTE Advanced: 3GPP Solution for IMT-Advanced

5.2 Uplink Carrier Aggregation Principle

The Release 8 uplink maximum bandwidth is 20 MHz and then a UE is transmitting that as contiguous resource block allocation with n times 180 kHz as discussed in Chapter 3. In Release 10 the uplink carrier aggregation principle is to enable the UE to transmit on multiple uplink carriers simultaneously, as shown in the Figure 5.1 for the FDD two uplink carriers case with a single downlink carrier. Depending on the spectrum allocation the uplink carrier aggregation use can be divided to three categories as follows:

Figure 5.1 Uplink carrier aggregation principle.

1. Transmitting two or more adjacent carriers. This is typically not possible with the paired band allocations but more as the property of the unpaired spectrum allocations (and then naturally operating in TDD mode). There are some frequency bands having more than 20 MHz per operator, especially in the 3.5 GHz range, though there it remains most likely that TDD will be also used.

2. Transmitting on two carriers in the same band but non-adjacent to each other. Similar to the downlink this is seen important for such a case when an operator holds non-contiguous spectrum allocation within the same band.

3. Transmitting two or more carriers with each of the carriers on different frequency band, with the inter-band uplink carrier aggregation. This is seen as the most typical uplink carrier ...