Ensuring Accurate ACPR Measurements of LTE Power Amplifiers
Application Notes
The 3GPP Long Term Evolution (LTE) initiative is intended to provide a framework for the evolution of 3G toward a high-data-rate, low-latency and packet-optimized radio-access technology. Its aim is to achieve a peak downlink cell data rate of greater than 100 Mbps and an increase in capacity of three to ive times compared with HSDPA (in the same bandwidth), with latency as low as 20 ms. While LTE has the potential to enhance 3G networks and enable signiicant new service opportunities in mobile TV and video, achieving success in consumer-enabled devices will not be easy. Among other things, it will require the engineer to pay close attention to the power ampliier (PA); a component which plays a key role in the LTE transmitter’s RF front-end. The PA contributes signiicantly to handset power consumption and as an active device, exhibits nonlinear behavior which can be problematic. LTE’s evolved Node B (eNB) power ampliier faces a similar problem and is compounded by the fact that it can be multi-carrier or even mixed-carrier. Optimal LTE system performance demands that the PA be both highly eficient and linear. Accurately testing the PA during design and optimization provides one means of achieving this goal.