Coded Auxiliary Pilots for Channel Estimation in FBMC-OQAM Systems

In this paper, we propose a novel scattered pilot method for channel estimation in filter-bank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) systems. We refer to this as the coded auxiliary pilot (CAP) method. It builds on the idea of using a few auxiliary pilot (AP) symbols to eliminate the imaginary interference on each scattered pilot. At the same time, to keep the spectral efficiency of transmission high, the AP symbols are coded to also carry information symbols. Theoretical analysis and numerical results show that the CAP method can maintain high spectral efficiency and high power efficiency, while achieving complete imaginary interference cancelation. Taking the spectral and power efficiency, the imaginary interference cancelation performance, and the coding/decoding complexity into consideration, the CAP method with two to four AP symbols is identified as a good compromised choice for practice.