Precoded and pre-equalized multi-band FBMC transmission enabled by radio-frequency DACs and the undersampling technique.

In this Letter, we use radio-frequency digital-to-analog converters (DACs) operating in different frequency response modes to generate a high spectral-efficiency multi-band (MB) filter bank multicarrier (FBMC) signal. In the receiver, the undersampling technique is employed to realize down-conversions. No electrical mixers are required. Besides, discrete Fourier transform and orthogonal circulant matrix transform precoding techniques combined with channel-independent digital pre-equalization are enabled to enhance transmission performance. Both numerical simulations and offline experiments are performed. The relevant results show that the MB-FBMC without a cyclic prefix (CP) is robust against inter-symbol interference induced by the band-pass filtering. By using precoding and pre-equalization techniques, the bit error rate can be improved by more than one order of magnitude. In contrast, an additional 12.5% CP overhead is required for the MB orthogonal frequency division multiplexing system to achieve such an improvement.