Implementation of 5G beamforming techniques on cylindrical arrays

In this paper we study the performance of a Uniform Cylindrical Array for a 5G base station working in the mmW region. Conventional and Capon beamforming design are considered. A comparison against a base station equipped with three Uniform Planar Arrays, one per sector, is presented. Average per-user achievable rate results are provided with different system configuration in terms of network loading and number of antennas, showing that Uniform Cylindrical Array could represent an interesting solution for 5GmmW networks

Analysis of circular and cylindrical array arrangements for mmwave 5G beamforming techniques

In this paper, we study the performance of a 5G base station working in the mmWave range equipped with a cylindrical array. Conventional and Capon beamforming techniques are taken into account. We consider both isotropic and directive antenna elements and we evaluate the trade-off between antennas per ring and number of rings with fixed number of total antennas. Results are provided in terms of average achievable per-user rate with different system configurations, such as of network loading. We show that in the presented scenario, where users are randomly deployed in a hexagonal plane, the best performance occurs when the cylindrical array degenerates in a circular array

5G beamforming implementation and trade-off investigation of cylindrical array arrangements

In this paper, we study the performance of a 5G network working at mmW range for the uplink. We consider a single base station scenario equipped with a cylindrical array and a circular array (which can be seen as a single ring cylindrical array), isotropic and directive antenna elements are taken into account and we evaluate the trade-off between antennas per ring and number of rings with fixed number of total antennas. Users are modeled as a spatial Binomial point process in a hexagonal cell. As beamforming techniques, Conventional and Capon algorithms have been considered. As main KPI to evaluate system performance, we consider average achievable per-user rate with different system configurations, such as network loading. The key result of the trade-off investigation is that, when the radius of the cell is much larger than the height of the base station, the best performance occurs when the cylindrical array degenerates in a circular array both when users lay at ground level and with random heights

Assessment of MU-MIMO schemes with cylindrical arrays under 3GPP 3D channel model for B5G networks

Beyond 5G technologies promise groundbreaking advances on the performance of cellular networks, by taking advantage of Massive MIMO in mmWave scenarios. The aim of this study is to analyze and test the performance of a 5G cell site equipped with large antenna arrays. It is of particular interest the comparison between the typical trisector cell design with a planar array for each sector, and the less investigated cylindrical array, able to maintain a constant pattern through the whole azimuthal range. To validate our analysis, we adopt the latest 3GPP-compliant 3D channel model and we evaluate the performance of multi-user and multi-layer precoding and combining schemes. Several MIMO configurations are taken into account, and we show that cylindrical arrays can improve the overall system performance, both in terms of achievable per-user rate and outage probability

Performance Analysis of Multi-User MIMO Schemes under Realistic 3GPP 3-D Channel Model for 5G mmWave Cellular Networks

Novel techniques such as mmWave transmission and massive MIMO have proven to present many attractive features able to support high data demand for 5G NR technologies. Towards the standardization of 5G networks, channel modeling has become an important step in order to test the reliability of theoretical studies. In this paper, we study the performance of a 5G network at mmWave range for the downlink. We consider a single trisectorized base station equipped with planar arrays, and we model users as a spatial Poisson process in a hexagonal grid. We adopt the latest 3GPP channel model described in TR 38.901 and we provide a thorough description and step-by-step tutorial of it along with our customizations and MATLAB scripts for channel generation in the presented scenario. Moreover, we evaluate the performance of Multi-User Multi-Layer MIMO techniques, such as Signal-to-Leakage-plus-Noise Ratio (SLNR) precoding and MMSE combined with different system configurations by means of achievable per-user rate

Improved Graph-Based User Scheduling For Sum-Rate Maximization in LEO-NTN Systems

In this paper, we study the problem of user scheduling for Low Earth Orbit (LEO) Multi-User (MU) Multiple-Input-Multiple-Output (MIMO) Non-Terrestrial Network (NTN) systems with the objective of maximizing the sum-rate capacity while minimizing the total number of clusters. We propose an iterative graph-based maximum clique scheduling approach with constant graph density. Users are grouped together based on the channel coefficient of correlation (CoC) as dissimilarity metric and served by the satellite via Space Division Multiple Access (SDMA) by means of Minimum Mean Square Error (MMSE) digital beamforming on a cluster basis. Clusters are then served in different time slots via Time Division Multiple Access (TDMA). The results, presented in terms of per-cluster sum-rate capacity and per-user throughput, show that the presented approach can significantly improve the system performance

Graph-Based User Scheduling Algorithms for LEO-MIMO Non-Terrestrial Networks

In this paper, we study the user scheduling prob-lem in a Low Earth Orbit (LEO) Multi-User Multiple-Input-Multiple-Output (MIMO) system. We propose an iterative graph-based maximum clique scheduling approach, in which users are grouped together based on a dissimilarity measure and served by the satellite via space-division multiple access (SDMA) by means of Minimum Mean Square Error (MMSE) digital beamforming on a cluster basis. User groups are then served in different time slots via time-division multiple access (TDMA). As dissimilarity measure, we consider both the channel coefficient of correlation and the users' great circle distance. A heuristic optimization of the optimal cluster size is performed in order to maximize the system capacity. To further validate our analysis, we compare our proposed graph-based schedulers with the well-established algorithm known as Multiple Antenna Downlink Orthogonal clustering (MADOC). Results are presented in terms of achievable per-user capacity and show the superiority in performance of the proposed schedulers w.r.t. MADOC

Joint Graph-based User Scheduling and Beamforming in LEO-MIMO Satellite Communication Systems

In this paper, a Low earth orbit (LEO) High-Throughput Satellite (HTS) Multi-User multiple-input multiple-output (MIMO) system is considered. With the objective of minimizing inter-beam interference among users, we propose a joint graph-based user scheduling and feed space beamforming framework for the downlink. First, we construct a graph where the vertices are the users and edges are based on a dissimilarity measure of their channels. Secondly, we design a low complexity greedy user clustering strategy, in which we iteratively search for the maximum clique in the graph. Finally, a Minimum Mean Square Error (MMSE) beamforming matrix is applied on a cluster basis with different power normalization schemes. A heuristic optimization of the graph density, i.e., optimal cluster size, is performed in order to maximize the system capacity. The proposed scheduling algorithm is compared with a position-based scheduler, in which a beam lattice is generated on ground and one user per beam is randomly selected to form a cluster. Results are presented in terms of achievable per-user capacity and show the superiority in performance of the proposed scheduler w.r.t. to the position-based approach

Evaluation of MU-MIMO Digital Beamforming Algorithms in B5G/6G LEO Satellite Systems

Satellite Communication (SatCom) systems will be a key component of 5G and 6G networks to achieve the goal of providing unlimited and ubiquitous communications and deploying smart and sustainable networks. To meet the ever-increasing demand for higher throughput in 5G and beyond, aggressive frequency reuse schemes (i.e., full frequency reuse), combined with digital beamforming techniques to cope with the massive co-channel interference, are recognized as a key solution. Aimed at (i) eliminating the joint optimization problem among the beamforming vectors of all users, (ii) splitting it into distinct ones, and (iii) finding a closed-form solution, we propose a beamforming algorithm based on maximizing the users' Signal-to-Leakage-and-Noise Ratio (SLNR) served by a Low Earth Orbit (LEO) satellite. We investigate and assess the performance of several beamforming algorithms, including both those based on Channel State Information (CSI) at the transmitter, i.e., Minimum Mean Square Error (MMSE) and Zero-Forcing (ZF), and those only requiring the users' locations, i.e., Switchable Multi-Beam (MB). Through a detailed numerical analysis, we provide a thorough comparison of the performance in terms of per-user achievable spectral efficiency of the aforementioned beamforming schemes, and we show that the proposed SLNR beamforming technique is able to outperform both MMSE and ZF schemes in the presented SatCom scenario

Evaluation of multi-user multiple-input multiple-output digital beamforming algorithms in B5G/6G low Earth orbit satellite systems

Satellite communication systems will be a key component of 5G and 6G networks to achieve the goal of providing unlimited and ubiquitous communications and deploying smart and sustainable networks. To meet the ever-increasing demand for higher throughput in 5G and beyond, aggressive frequency reuse schemes (i.e., full frequency reuse), combined with digital beamforming techniques to cope with the massive co-channel interference, are recognized as a key solution. Aimed at (i) eliminating the joint optimization problem among the beamforming vectors of all users, (ii) splitting it into distinct ones, and (iii) finding a closed-form solution, we propose a beamforming algorithm based on maximizing the users' signal-to-leakage-and-noise ratio served by a low Earth orbit satellite. We investigate and assess the performance of several beamforming algorithms, including both those based on channel state information at the transmitter, that is, minimum mean square error and zero forcing, and those only requiring the users' locations, that is, switchable multi-beam. Through a detailed numerical analysis, we provide a thorough comparison of the performance in terms of per-user achievable spectral efficiency of the aforementioned beamforming schemes, and we show that the proposed signal to-leakage-plus-noise ratio beamforming technique is able to outperform both minimum mean square error and multi-beam schemes in the presented satellite communication scenario