A Filter-Bank Transceiver Architecture for Massive Non-Contiguous Carrier Aggregation

Current application of carrier aggregation (CA), a key enabling technology for wideband communications over fragmented spectrum, is limited to only a small number of component carriers (CCs). However, wireless broadband connectivity of future networks requires the exploitation of multiple, contiguous, and non-contiguous CCs (NC-CCs). By considering a large number of aggregated NC-CCs, the concept of massive non-contiguous CA (NC-CA) is realized, which offers the highest flexibility in spectrum aggregation. In order to fully exploit the system-level benefits of massive NC-CA, transceivers capable of efficiently accommodating parallel transmissions over all of the available NC-CCs are required. This is a challenging task in which current NC-CA transceiver architectures, including the straightforward parallel chains implementation, fail to accomplish, as they suffer from scalability and efficiency issues. Focusing on the digital baseband processing part of the transceiver, this paper proposes an efficient filter-bank transceiver architecture able to accommodate a large number of NC-CCs with a small complexity increase compared with the ideal case of the transceiver operating on a single CC with the same aggregate bandwidth. Specification of this new architecture is cast as a filter design problem with minimal assumptions on transmitted waveform format, channel statistics, and decoding scheme, allowing for universally applicable designs. Both heuristic and optimal design methodologies are provided, the latter obtained using the notion of capacity mean square error as an appropriate performance/design metric. The performance of the proposed architecture is evaluated analytically, and a case study where it is applied for OFDM transmissions is provided.