This subproject aims to address advanced digital processing solutions to ensure the integrity of the communications signal in the highly efficient 5G New Radio (NR) transceiver systems. The global and optimized management of resources (both computational and transmitted power, frequency bands, number of antennas, etc.) of the whole communication system will be pursued through technologies and management methods based on the concept of the cloud. Some of the technological challenges of the NR-5G that must be addressed in the design of radio transceivers in the sub 6 GHz band are related to: (a) ensuring the linearity of signals having bandwidths of hundreds of MHz (always increasing trend) and peak factors exceeding 10 dB (due to multi-carrier modulations) in order to ensure high transmission rates; b) improving energy and computational efficiency, as more dense deployments of base stations is expected to scale down the need for transmitted power; c) transmitting architectures with multiple antennas (massive MIMO in millimeter bands) and multiple power amplifiers to apply beamforming techniques that allow increasing the capacity and decreasing the radiated power; d) simultaneous transmission and reception (full-duplex FDD in sub 6GHz bands). In this context, the following specific objectives will be pursued: 1) Design of digital baseband processing solutions for linear and nonlinear distortion compensation of sub-6 GHz ultra-wideband or multi-band NR-5G systems. To do this we will use advanced systems estimation techniques to deal a big number of variables and sub-sampling techniques to reduce the specifications of the ADCs; 2) Implementation of an analog-digital hybrid predistorter (digital baseband in-band distortion compensation and analog RF out-of-band distortion compensation) for bandwidth signals of several hundreds of MHz; 3) Development of the necessary digital baseband signal processing (signal generation, mismatch control and linearization) to guarantee linearity levels in highly efficient amplification topologies based on dynamic supply strategies (class G amplifier, envelope tracking) or dynamic load modulation strategies (Doherty amplifier or hybrid outphasing); 4) Characterization and compensation of the interferences at the receiver due to non-linear distortion in concurrent multi-band transmissions, in which different transmitters and receivers share antenna through a frequency selective multiport device. The incorporation of the cloud concept into a mobile communications environment represents a relevant change in both the radio technologies to be applied and in the methodologies for development, deployment and management of the system. The C-RAN concept, with centralized management of Remote Radio Heads (RRHs), promises a high capacity increase by enabling the coordination of different RRHs and the application of Cooperative Multi-Point (CoMP) techniques, Massive MIMO, etc. The concept of software radio and resources virtualization are aspects to which ETSI is making significant efforts with the definition and development of the concept of Network Function Virtualization (NFV) and its Management and Orchestration (MANO-NFV). In this context, the following specific objectives are proposed: 1) Development of an RRH for C-RAN and 5G; 2) Analysis of the management needs for C-RAN LTE / 5G according to the MANO-NFV scheme; 3) Development of a C-RAN LTE / 5G testbed incorporating MANO-NFV.
Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016
Programa Estatal de I+D+i Orientada a los Retos de la Sociedad