Filter Bank Multi-Carrier (FBMC) modulation is considered as a possible candidate for 5G. Compared to OFDM, channel estimation becomes more challenging in FBMC due to the imaginary interference, which has to be canceled at the pilot positions either by auxiliary pilot symbols or coding.

Novel contribution
1. We formulate general conditions on the auxiliary pilot symbols, capturing also the interdependency of closely spaced pilots and an arbitrary number of auxiliary pilot symbols.
2. Previous authors consider only coding of up to N = 8 symbols. We propose an algorithm to design the coding matrix required for an arbitrary number of coded symbols.
3. We quantify the complexity difference between auxiliary pilot symbols and coding.