Power amplifier nonlinearity effects on OFDM subcarrier transmit beamforming

The effect of a power amplifier nonlinearity on multi-antenna orthogonal frequency division multiplexing (OFDM) transmitters utilizing subcarrier beamforming is investigated. Theoretical analysis and simulation shows that such systems can exhibit significant performance degradation due to the power amplifier nonlinearity when there are channel state feedback errors. The SINR degradation under solely channel mismatch is shown to be significantly better than when power amplifier nonlinearity effects are included. The ultimate conclusion is that power amplifier nonlinearity effects should be considered when designing per subcarrier transmit beamformers.