PT-CMA and PT-MMA for OFDM in Wireless Communication

In this paper we introduce a new blind adaptive per tone equalization scheme in OFDM systems. The proposed equalizer scheme consists of a (complex) equalizer per tone. In this scheme, we compare the performance of the per tone multimodulus algorithm (PT-MMA) with the per tone constant modulus algorithm (PT-CMA). The PT-CMA for blind equalization requires a separate carrier-recovery system for phase recovery, but the PT-MMA performs joint blind equalization and carrier recovery without the need for a separate carrier-recovery system for QAM signal constellations. The PT-MMA compensates for an additional carrier frequency offset (CFO). The results of our simulations indicate that the PT-MMA can correct the phase error, because it implicitly incorporates a phase-tracking loop, which automatically recovers carrier phase.