Abstract: A multi-beam antenna system, apparatus and method for dynamic carrier aggregation to multi-beam antenna mapping in radio access networks, including small-cell deployments, is disclosed. Apparatus comprises a compact base transceiver unit with integrated multi-beam antenna comprising antenna groups configurable for operation in a plurality of modes, with one or more selected antenna groups enabled, for different use-case scenarios. The base transceiver unit comprises a daisy-chained radio-frequency (RF) system wherein one baseband processor feeds multiple RF transceivers; each RF transceiver front end comprises a software configurable isolation module through which each RF front end is interlinked to previous and next RF front ends to enable dynamic routing of TX/RX data streams through the daisy chain, e.g.