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. routing a transmission data stream from any RF transceiver to any one of the antenna groups or multiple antenna groups, routing a received data stream from one or multiple antenna groups to any RF transceiver, and for contiguous or non-contiguous carrier aggregation.