Enhanced Precoding Design with Adaptive Beam Width for 5G New Radio Systems

Multiple-Input Multiple-Output (MIMO) is considered as a key technology for next generation wireless cellular systems. Depending on the scenario and propagation environment the optimal beamwidth of the precoding vectors in MIMO systems can be different. Precoding vectors corresponding to narrow beams are most appropriate in several scenarios, as they provide maximum beamforming gain in the desired direction and generate less interference in other directions. However, in some cases the use of only narrow beams for precoding is not optimal. For example, to increase the spatial multiplexing gains and the number of transmitted MIMO layers, the precoding vectors corresponding to wider beams should be also considered. Moreover, for open-loop transmission schemes, the use of precoding with wider beamwidth results in better diversity and, therefore, improved performance. To accommodate the variable beamwidth requirement for MIMO beamforming, this paper proposes an enhanced precoding approach with adaptive beamwidth of the precoding vectors for 5G New Radio (NR) systems. System-level and link- level performance evaluation results show that the proposed precoding vector structure with adaptive beamwidth of the precoding vectors outperforms conventional DFT-based precoding with narrow beamwidth supported in LTE-A systems.