Adaptive equalization for filter bank based multicarrier systems

Filter bank based multicarrier systems (FBMC) offer a number of benefits over conventional orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP). One benefit is the improved spectral efficiency by not using a redundant CP and by having much better control of out-of-band emission. Another advantage is the ease of accomodating multiple users in an FDMA fashion especially in the uplink, i. e. the multiple access channel (MAC). On the other hand, more elaborate equalization concepts are needed compared to the single-tap per-subcarrier equalizer sufficient in the OFDM with CP case. Therefore, we will present a least-mean-square (LMS) algorithm which is adapted to the principle of orthogonally multiplexed QAM filter banks (OQAM-FBMC). This leads to an adaptive equalizer solution with low complexity. The initialization of the LMS equalizer results from a pilot based channel estimation. The results will be compared with a classical OFDM system, where the loss in data rate is compensated with a higher modulation scheme.