An integrated system evaluation engine for cross-domain simulation and design optimization of a transceiver front-end dealing with complex OFDM signals

Traditionally, a continuous-wave (CW) signal is used to simulate RF circuits during the design procedure, while the fabricated circuits are measured by modulated signals in the test phase, because modulated signals are used in reality. It is almost impossible to use a CW signal to predict system performances, such as error vector magnitude (EVM), bit error rate (BER), etc., of a transceiver front-end when dealing with complex modulated signals. This paper develops an integrated system evaluation engine (ISEE) to evaluate the system performances of a transceiver front-end or its sub-circuits. This cross-domain simulation platform is based on Matlab, advanced design system (ADS), and Cadence simulators to link the baseband signals and transceiver frond-end. An orthogonal frequency division multiplex (OFDM) modem is implemented in Matlab for evaluating the system performances. The modulated baseband signal from Matlab is dynamically fed into ADS, which includes transceiver front-end for co-simulation. The sub-block circuits of the transceiver front-end can be implemented using ADS and Cadence simulators. After system-level circuit simulation in ADS, the output signal is dynamically delivered to Matlab for demodulation. To simplify the use of the co-simulation platform, a graphical user interface (GUI) is constructed using Matlab. The parameters of the OFDM signals can be easily reconfigured on the GUI to simulate RF circuits with different modulation schemes. To demonstrate the effectiveness of the ISEE, a 3.5 GHz power amplifier is simulated and characterized using 20 MHz 16- and 64-QAM OFDM signals.