Power Efficient Scattered Pilot Channel Estimation for FBMC/OQAM

Filter bank multicarrier transmission with offset-QAM (FBMC/OQAM) is a promising candidate waveform for the next mobile communication systems as it is well suited for many new scenarios and challenges like improved spectral efficiency, spectrum sharing approaches or high mobility scenarios. It does not require a cyclic prefix (CP) leading to a higher spectral efficiency than orthogonal frequency division multiplexing with CP (CP-OFDM) and the flexibility of the transmit and receive filters enables higher throughput in spectral sharing and high mobility scenarios. One aspect to be considered is efficient channel estimation that is needed in order to realize these gains. As the classical channel estimation used for CP-OFDM cannot be applied directly to FBMC/OQAM, new competitive solutions are needed. One promising solution for the pilot design suited for FBMC introduces an auxiliary pilot (precoding symbol) that nullifies the intrinsic interference at the pilot position, but this leads to increased power on these auxiliary pilots. In this paper, a new non-linear scattered pilot design and channel estimation technique is proposed that addresses the problem of increased power of the auxiliary pilot. In addition to the reduced transmit power, we also observe that the receive power at the pilot position is increased with this new proposal which leads to an improved channel estimation performance.