Power Scaling Method for Uplink Power Control with Carrier Aggregation

According to 3GPP RAN1 conference, power scaling for uplink power control should be applied equally. However, the detail of power scaling is a remaining issue. In this contribution, we clarify some cases of power scaling and propose several options of power scaling on PUSCHs. It is not clear that whether the equal power scaling is relative to the allocated transmission power after or before power truncation is applied in the CC-specific PC formula. Since link adaptation at the eNodeB is typically performed assuming that the UE will transmit with the allocated transmission power, distribution of power after scaling should be as close as possible to the distribution of power before scaling. From these criteria, two new methods for power scaling are introduced. One of these two methods (option 3) has the optimal performance such that to apply power scaling on all PUSCHs without UCI in the sense that it is as equal as possible. Whereas another method (option 4) has less complexity such that each type of CCs which is treated as a whole would be applied equal power scaling. From the results of simulation, it shows that equal power scaling could have the optimal average performance. Therefore, the equal power scaling rules should be hold whatever the scaling algorithms are adopted for uplink power control.