A carrier recovery architecture for next generation wideband modems

We propose a joint matched filtering (MF) and carrier recovery architecture based on perfect reconstruction (PR) non-maximally decimated filter bank (NMDFB). The NMDFB based processing not only provides low speed processing feature but also effectively deals with the cascade and parallel filtering problems that most conventional receivers adopt. We will show the NMDFB implementation of conventional receivers offers significant workload reduction. Given the PR property, any desired spectral shape can be well approximated by properly designing the analysis/synthesis chain with intermediate processing elements (IPEs), which transforms the conventional filters into IPE processors. The proposed carrier recovery is implemented by performing band-edge (BE) filtering in the channelized domain. The error from the synthesized BE filter outputs drives the frequency locked loop (FLL) and the IPE based low speed direct digital synthesizer (DDS). Similarly, the constellation phase offset is removed via phase shifter IPE driven by a phase locked loop (PLL). And, the MF is performed via a third spectral shaping IPE. Compared to existing architectures, the proposed approach implements close to optimal BE filters while exhibiting significant workload reduction.