Tree-structured MIMO FIR Filter Banks for Flexible Frequency Reallocation

Emerging digital on-board processors for communication satellites concurrently call for two tasks of a cascade of a frequency demultiplexer (FDMUX) and a frequency multiplexer (FMUX): i) mere de-and remultiplexing of an FDM signal (FDFMUX functionality) and ii) decomposition and reconstruction of a wideband signal (Sub-band Coding (SBC) functionality). In this paper, two FIR approaches allowing for flexible frequency reallocation, the oversampling 2times2-channel and the critically sampling 2-channel FIR SBC-FDFMUX filter banks, are investigated and compared with each other. Furthermore, tree-structured MIMO extensions of both approaches including the application of switching functions are investigated. The oversampling 2times2-channel SBC-FDFMUX filter bank moderately outperforms the critically sampling 2-channel SBC-FDFMUX filter bank in terms of computational complexity, whereas the latter is highly modular and, hence, simply realisable.