Analysis of Maximum Power Reduction of Uplink for Carrier Aggregation in LTE-A System

Carrier Aggregation (CA) technique is adopted by LTE-A system to achieve high performance in data rate and spectral efficiency. However, CA technique will drive the Peak to Average Power Ratio (PAPR) of uplink signal to the extreme level. PAPR remains an important issue for a LTE-A User Equipment (UE) because it determines the PA efficiency and the coverage when multi-carrier transmission is employed. The uplink signal with a high level of PAPR will be severely affected by the nonlinearity of Power Amplifier (PA) and brings unacceptable interference into adjacent channels. To mitigate the interference, this paper introduces a well-known linearization technique named back off of UE transmission power and analyzes the factors which actually influence the value of power back off needed represented by Maximum Power Reduction (MPR). Based on theoretical analysis and experimental results, this paper provides credible references to the similar research and the RF design of UE especially in LTE-A system.