A Crest Factor Reduction Scheme with Optimum Spacing Peak Cancellation for Intra-band Non-contiguous Carrier Aggregated OFDM Signals

This paper proposes a new crest factor reduction scheme to reduce instantaneous-to-average power ratio (IAR) resulting decent peak reduction, and adjacent channel leakage ratio (ACLR) reduction, though the error vector magnitude (EVM) is significantly enhanced. In the conventional peak cancellation (CPC) technique, peak regrowth occurs as a result of finite impulse response (FIR) filter windows overlapping. The peak regrowth problem in CPC technique can be compensated, though this will lead to increased computational complexity and degradation in EVM. The proposed algorithm allocates spacing to contiguous peaks to avoid FIR filter windows overlapping. Two types of overlapping are discussed, incremental and decremental. The optimum spacing can be determined from the FIR filter impulse response characteristic. Simulations are carried out with different intra-band non-contiguous carrier aggregated OFDM signals. The results of simulations show between 3 and 10% improvement in EVM performance while maintaining equivalent IAR and ACLR performance. Applying the proposed optimum spacing peak cancellation scheme compared to the conventional peak cancellation technique.