Energy Efficient Massive MIMO Array Configurations

The high spectral efficiency of massive MIMO (Multiple Input Multiple Output) is mainly achieved through the exploitation of spatial multiplexing, i.e. by using a high number of MIMO layers that are applied simultaneously to many users. The power consumption of a massive MIMO base station is determined by the hardware driving a high number of antenna ports and elements. This paper focuses on practical deployment situations with varying user load. During hours with low number of users a certain significant part of hardware power consumption would remain with conventional massive MIMO processing, while the full potential of spectral efficiency cannot be exploited due to the low number of users, resulting in low power efficiency and cost. We investigate the impact of different hybrid array architectures on spectral efficiency, average user throughput and power consumption and show how to design a massive MIMO system with significantly improved energy efficiency for a given target scenario, while maintaining a targeted service quality

Waveforms for sub-THz 6G: Design Guidelines

The projected sub-THz (100 - 300 GHz) part of the upcoming 6G standard will require a careful design of the waveform and choice of slot structure. Not only that the design of the physical layer for 6G will be driven by ambitious system performance requirements, but also hardware limitations, specific to sub-THz frequencies, pose a fundamental design constraint for the waveform. In this contribution, general guidelines for the waveform design are given, together with a non-exhaustive list of exemplary waveforms that can be used to meet the design requirements.Comment: Paper presented at EuCNC 2023, June 6-9 2023, Gothenburg, Swede

Performance evaluation of analog beamforming with hardware impairments for mmW massive MIMO communication in an urban scenario

[EN] The use of massive multiple-input multiple-output (MIMO) techniques for communication at millimeter-Wave (mmW) frequency bands has become a key enabler to meet the data rate demands of the upcoming fifth generation (5G) cellular systems. In particular, analog and hybrid beamforming solutions are receiving increasing attention as less expensive and more power efficient alternatives to fully digital precoding schemes. Despite their proven good performance in simple setups, their suitability for realistic cellular systems with many interfering base stations and users is still unclear. Furthermore, the performance of massive MIMO beamforming and precoding methods are in practice also affected by practical limitations and hardware constraints. In this sense, this paper assesses the performance of digital precoding and analog beamforming in an urban cellular system with an accurate mmW channel model under both ideal and realistic assumptions. The results show that analog beamforming can reach the performance of fully digital maximum ratio transmission under line of sight conditions and with a sufficient number of parallel radio-frequency (RF) chains, especially when the practical limitations of outdated channel information and per antenna power constraints are considered. This work also shows the impact of the phase shifter errors and combiner losses introduced by real phase shifter and combiner implementations over analog beamforming, where the former ones have minor impact on the performance, while the latter ones determine the optimum number of RF chains to be used in practice.The research done by P. Baracca, V. Braun, and H. Halbauer leading to these results received funding from the European Commission H2020 programme under grant agreement number 671650 (mmMAGIC project). The work carried out at the Universitat Politècnica de València was supported by the Ministerio de Economia y Competitividad, Spain (TEC2014-60258-C2-1-R) by the European FEDER funds.Giménez Colás, S.; Roger Varea, S.; Baracca, P.; Martín-Sacristán, D.; Monserrat Del Río, JF.; Braun, V.; Halbauer, H. (2016). Performance evaluation of analog beamforming with hardware impairments for mmW massive MIMO communication in an urban scenario. Sensors. 16(10):1-17. https://doi.org/10.3390/s16101555S117161

Towards versatile access networks (Chapter 3)

Compared to its previous generations, the 5th generation (5G) cellular network features an additional type of densification, i.e., a large number of active antennas per access point (AP) can be deployed. This technique is known as massive multipleinput multiple-output (mMIMO) [1]. Meanwhile, multiple-input multiple-output (MIMO) evolution, e.g., in channel state information (CSI) enhancement, and also on the study of a larger number of orthogonal demodulation reference signal (DMRS) ports for MU-MIMO, was one of the Release 18 of 3rd generation partnership project (3GPP Rel-18) work item. This release (3GPP Rel-18) package approval, in the fourth quarter of 2021, marked the start of the 5G Advanced evolution in 3GPP. The other items in 3GPP Rel-18 are to study and add functionality in the areas of network energy savings, coverage, mobility support, multicast broadcast services, and positionin

Wimax Performance Impacts in Multi-Cell Deployments

This paper presents the application of the multiple antenna schemes beamforming (BF) and Multiple Input Multiple Output (MIMO) in the broadband wireless access system WiMAX. The evaluation considers the competing performance demands on link robustness and peak data rate. Configurations for both uplink and downlink are discussed. We conclude that future wireless communications will rely on diverse and adaptive multiple antenna schemes to meet their requirements, in particular in the presence of strong co-channel interference

Advanced interference management in ARTIST4G: Interference Avoidance

This paper gives an overview of the objectives and current research activities on interference avoidance in the EC funded research project ARTIST4G. It is the main objective of the ARTIST4G Work Package 1 (WP1), to build forward on the 3GPP LTE Release 8 baseline, proposing a novel fair mobile broadband technological framework in which to design innovative, practical, scalable and cost-effective interference avoidance solutions. This paper provides an overview of the fundamental classes of innovations studied in ARTIST4G Work Package 1 (WP1) and presents some performance results obtained by means of numerical simulations and test-bed measurements run in the field

EU FP7 INFSO-ICT-247223 ARTIST4G, D1.1 Definitions and architecture requirements for supporting interference avoidance techniques

It is the main objective of the ARTIST4G Work Package 1 (WP1), to design innovative interference avoidance solutions by means of transmitter signal processing, scheduling and/or cross layer techniques. Such an approach will enable to identify optimal strategies also taking into account the practical implications on the real system. The major impacts of the WP1 innovations on the radio access network and on the mobile system interfaces, together with constraints due to practical implementations, will be analyzed in this deliverable. This deliverable will be a reference for the work in ARTIST4G Work Package 4 (WP4).A set of guiding questions used to precise the requirements for WP4 has been considered for each new cooperation/coordination functionality. Answers to these questions are provided in this deliverable by grouping the different classes of WP1 innovations into 4 categories with similar requirements on the radio access architecture. For each question, current, expected, minimum and maximum targets of the requirement will be given, helping to ensure that the range of all possible values for all the innovations are taken into account

EU FP7 INFSO-ICT-247223 ARTIST4G, D1.1 Definitions and architecture requirements for supporting interference avoidance techniques

It is the main objective of the ARTIST4G Work Package 1 (WP1), to design innovative interference avoidance solutions by means of transmitter signal processing, scheduling and/or cross layer techniques. Such an approach will enable to identify optimal strategies also taking into account the practical implications on the real system. The major impacts of the WP1 innovations on the radio access network and on the mobile system interfaces, together with constraints due to practical implementations, will be analyzed in this deliverable. This deliverable will be a reference for the work in ARTIST4G Work Package 4 (WP4).A set of guiding questions used to precise the requirements for WP4 has been considered for each new cooperation/coordination functionality. Answers to these questions are provided in this deliverable by grouping the different classes of WP1 innovations into 4 categories with similar requirements on the radio access architecture. For each question, current, expected, minimum and maximum targets of the requirement will be given, helping to ensure that the range of all possible values for all the innovations are taken into account