A Practical Multi-band Large Scale Antenna System Architecture for Next Generation Wireless Networks

Due to its promising spectrum utilization efficiency, large scale antenna system (LSAS) has been identified as one of the key technologies for the coming 5G wireless networks. And it will be more beneficial when combining LSAS with multi-band radio technology for further boosting the network capacity and data throughput. However, this concept dramatically increases the system complexity and cost because of the architectural requirement of many multi-band RF transceivers. It may even block the way of deploying this technology in the field. Therefore in order to make the technology closer to the real applications, in this letter, we propose a practical system architecture for multi-band LSAS, which provides flexible re-configurable functionality and scalable deployment capability. The essential parts of the proposed architecture comprises of 1) a cloud-based virtual base-station (VBS), 2) signal conditioning processing modules, 3) open-flow like signal switches, 4) digital RF transceiver modules and 5) multi-band large scale antenna array module. Besides the utilization of virtualized baseband units, our proposed architecture mainly differentiates itself from other existing architectures is the introduction of the open-flow like signal switch, which is used to create one more remotely controllable network sub-layer. By using this newly created open-flow like switch unit, the LSAS will be physically able to re-configure its operation modes and to expand the system seamlessly regarding both RF parts and digital parts. In order to preliminarily verify this key function, we created a simplified RFDAC-based multi-band transmitter with a high speed FPGA-based signal switch and a MATLAB-based graphic user control plane.