Digital predistortion linearizer for multicarrier spread spectrum

This paper analyzes an OFDM-CDMA system with a digital predistortion linearizer. Digital predistortion was the linearizer of choice since it has no stability problems with wideband signals and can be implemented as a fully adaptive digital solution which lends itself to operation not only in the base station but in a mobile unit as well. Results show that for this particular amplifier, a 3 to 4 dB improvement in output back off is achieved with a corresponding increase in amplifier efficiency of about 25 to 30%. This was achieved with equal or improved bit error rate performance with respect to the nonlinear case.