Measurement Setup

The remoteUPCLab infrastructure, which allows users to remotely send and receive beyond 4G waveforms for DPD benchmarking, is based on a Rohde & Schwarz (R&S) SMW200A vector signal generator (VSG) and a R&S FSW8 signal and spectrum analyzer (SSA) communicating with a control PC running a MATLAB FTP server application.

This year’s competition intends to linearize a Skyworks SKY77621 Multimode Multiband (MMMB) 4G handset PA being operated at 1950 MHz which is included in the Texas Instrument (TI) LM3290-91-1EVM dynamic supply / envelope tracking (ET) evaluation module (EVM). The competition’s focus will be put not only in improving the system performance, but increasing the energy efficiency of the module under test: The EVM power consumption will be measured and the PA efficiency will be accounted in the scoring system, together with the PA output power at which it is achieved, and the NMSE and the ACPR performance metrics, as described in the Competition Details submenu.

The remoteUPCLab server receives the incoming baseband I/Q waveforms and an appropriate delay-compensated supply waveform from a remote user. These are both downloaded into the VSG that generates i) the I/Q signals being RF up converted to deliver the PA input signal (i.e. through the VSG I/Q modulator) and ii) the EVM supply modulator input signal.

The SSA is in charge of RF down conversion and data acquisition of the waveform at the output of the PA, whose I/Q data will be sent back to the remote user for DPD processing.

The PA will be operating with a dual-band signal composed by two OFDM signals whose center frequency is spaced 80 MHz and that feature 10 MHz and 5 MHz bandwidth. The baseband clock that will be employed in the signal processing operations is 122.88 MHz which corresponds also to the I/Q A/D and D/A sampling frequencies (no oversampling is applied). The peak output power level from the SKY77621 PA is limited to approximately 1W. The settings in the signal analyzer (reference level and input attenuation) are set in such a way as not to distort the measured signal even for the highest peak power levels allowed.

We appreciate the support of Hermann Boss, Martin Breinbauer and David Gonzalo from Rhode & Schwarz in making available both the instrumentation and ET EVM, and in building the ET-DPD test setup.