5.4 Physical Layer Impact from Uplink Carrier Aggregation

The PUCCH is always transmitted only in the PCell, regardless of whether there are more uplink component carriers configured for the UE. If there is uplink data scheduled in the PCell, then control is multiplexed on the PUSCH together with data in-line with the Release 8 uplink principles as was discussed in Chapter 3. The new element for the uplink in Release 10 (regardless whether uplink carrier aggregation is used or not) is the possibility to send simultaneous PUCCH and PUSCH, something which was not possible in Release 8 or 9. The principle of simultaneous PUCCH and PUSCH is shown in Figure 5.4.

Figure 5.4 Simultaneous PUCCH and PUSCH.

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The use of simultaneous PUSCH and PUCCH has the benefit of being able to set independently the power level between control and data since the data is protected by the physical layer retransmissions while the control signalling needs to go through in one go. With the simultaneous PUSCH and PUSCH transmission there are now more possibilities for the frequency specific scheduling in the uplink direction as previously only continuous allocation was used. The use of simultaneous control and data (or two simultaneous data resource allocations) transmission, however, causes two parallel SC-FDMA transmissions to take place within the uplink allocations if a single uplink component carrier is ...

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