FBMC Design and Implementation

Abstract

The focus in this chapter is on effective practical implementation schemes for the filterbanks, with the main focus on the FilterBank MultiCarrier with Offset-QAM subcarrier modulation (FBMC/OQAM) case. In the first part, effective modulation-based uniform filterbank structures are used, and the designs are defined by the lowpass prototype filter. Two alternative design approaches are considered. The first approach starts from continuous-time formulation of the prototype filter responses, which are then discretized. Alternatively, the design problem can be formulated as a lowpass digital filter optimization problem with additional constraints to guarantee the orthogonality of subcarriers. While introducing the effective filterbank structures, the main emphasis is on the polyphase FilterBank (FB) model, but the lattice structure and lapped transform-based structure are briefly introduced as well. In the second part of this chapter, a fast-convolution based scheme for implementing uniform and nonuniform filterbanks in effective and flexible manner is introduced. This section develops an effective model for the frequency-response analysis and optimization of such FBs, explores various practical issues, and reports the optimized frequency-response characteristics versus analytical direct designs. This approach is shown to be a competitive basis for FB-based multicarrier and single-carrier waveform processing in terms of spectral containment and complexity.