Multi-user MIMO offers big advantages over conventional point-to-point MIMO: it works with cheap single-antenna terminals, a rich scattering environment is not required, and resource allocation simplified because every active terminal utilizes all of the time-frequency bins. However, multi-user MIMO, as originally envisioned, roughly equal numbers service antennas terminals frequency-division duplex operation, scalable technology. Massive (also known large-scale antenna systems, very large...

This paper surveys recent advances in the area of very large MIMO systems. With MIMO, we think systems that use antenna arrays with an order magnitude more elements than being built today, say a hundred antennas or more. Very entails unprecedented number simultaneously serving much smaller terminals. The disparity emerges as desirable operating condition and practical one well. terminals can be served is limited, not by antennas, but rather our inability to acquire channel-state information...

There is considerable pressure to define the key requirements of 5G, develop 5G standards, and perform technology trials as quickly possible. Normally, these activities are best done in series but there a desire complete tasks parallel so that commercial deployments can begin by 2020. will not be an incremental improvement over its predecessors; it aims revolutionary leap forward terms data rates, latency, massive connectivity, network reliability, energy efficiency. These capabilities...

Mobile communications have been undergoing a generational change every ten years or so. However, the time difference between so-called "G's" is also decreasing. While fifth-generation (5G) systems are becoming commercial reality, there already significant interest in beyond 5G, which we refer to as sixth generation (6G) of wireless systems. In contrast published papers on topic, take top-down approach 6G. More precisely, present holistic discussion 6G beginning with lifestyle and societal...

The COST 2100 channel model is a geometry- based stochastic (GSCM) that can reproduce the properties of MIMO channels over time, frequency, and space. In contrast to other popular GSCMs, approach generic flexible, making it suitable multi-user or distributed scenarios. this article concise overview presented. Main concepts are described, together with useful implementation guidelines. Recent developments, including dense multipath components, polarization, multi-link aspects, also discussed.

Massive MIMO, also known as very-large MIMO or large-scale antenna systems, is a new technique that potentially can offer large network capacities in multi-user scenarios. With massive system, we consider the case where base station equipped with number of elements simultaneously serves multiple single-antenna users same time-frequency resource. So far, investigations are mostly based on theoretical channels independent and identically distributed (i.i.d.) complex Gaussian coefficients,...

To make transportation safer, more efficient, and less harmful to the environment, traffic telematics services are currently being intensely investigated developed. Such require dependable wireless vehicle-to-infrastructure vehicle-to-vehicle communications providing robust connectivity at moderate data rates. The development of such vehicular communication systems standards requires accurate models propagation channel in all relevant environments scenarios. Key characteristics channels...

Traffic telematics applications are currently under intense research and development for making transportation safer, more efficient, environmentally friendly. Reliable traffic services require vehicle-to-vehicle wireless communications that can provide robust connectivity, typically at data rates between 1 10 Mb/s. The of such VTV systems standards require, in turn, accurate models the propagation channel. A key characteristic channels is their temporal variability inherent...

5G technologies present a new paradigm to provide connectivity vehicles, in support of high data-rate services, complementing existing inter-vehicle communication standards based on IEEE 802.11p. As we argue, the specific signal characteristics turn out be highly conducive for vehicle positioning. Hence, can work synergy with on-vehicle positioning and mapping systems redundancy certain applications, particular automated driving. This article provides an overview evolution cellular discusses...

Assisted living (AL) technologies, enabled by technical advances such as the advent of Internet Things, are increasingly gaining importance in our aging society. This article discusses potential future high-accuracy localization systems a key component AL applications. Accurate location information can be tremendously useful to realize, e.g., behavioral monitoring, fall detection, and real-time assistance. Such services expected provide older adults people with disabilities more independence...

Vehicle-to-vehicle (VTV) wireless communications have many envisioned applications in traffic safety and congestion avoidance, but the development of suitable systems standards requires accurate models for VTV propagation channel. In this paper, we present a new wideband multiple-input-multiple-output (MIMO) model channels based on extensive MIMO channel measurements performed at 5.2 GHz highway rural environments Lund, Sweden. The measured characteristics, particular nonstationarity...

Very large MIMO is a technique that potentially can offer network capacities in multi-user scenarios where the users are equipped only with single antennas. In this paper we investigating channel properties for realistic, though somewhat extreme, outdoor base station scenario using array. We present measurement results 128 element linear array and 26 different user position line-of-sight (LOS) 10 non (NLOS). analyze Ricean K-factor, received power levels over array, antenna correlation...

Wireless communication using very-large multiple-input multiple-output (MIMO) antennas is a new research field, where base stations are equipped with very large number of as compared to previously considered systems. In theory, the increases, propagation properties that were random before start become deterministic. Theoretical investigations independent identically distributed (i.i.d.) complex Gaussian (Rayleigh fading) channels and unlimited have been done, but in practice we need know...

Efficient and realistic mm-wave channel models are of vital importance for the development novel wireless technologies. Though many current 60 GHz based on useful concept multipath clusters, only a limited number measurements have been reported in literature this purpose. Therefore, there is still need further measurement analyses clustering band. This paper presents results double-directional MIMO model. Based these results, we derive model which validated with measured data. Statistical...

Vehicle-to-vehicle (V2V) communications have received increasing attention lately, but there is a lack of reported results regarding important quantities such as path loss. This paper presents parameterized loss models for V2V based on extensive sets measurement data collected mainly under line-of-sight conditions in four different propagation environments: highway, rural, urban, and suburban. The show that the exponent low communications, i.e., slowly increases with distance. We compare our...

Massive MIMO can greatly increase both spectral and transmit-energy efficiency. This is achieved by allowing the number of antennas RF chains to grow very large. However, challenges include high system complexity hardware energy consumption. Here we investigate possibilities reduce required chains, performing antenna selection. While this approach not a effective strategy for theoretical independent Rayleigh fading channels, substantial reduction in be real massive without significant...

Massive multiple-input multiple-output (MIMO) is one of the main candidates to be included in fifth generation (5G) cellular systems. For further system development it desirable have real-time testbeds showing possibilities and limitations technology. In this paper we describe Lund University MIMO testbed — LuMaMi. It a flexible where base station operates with up 100 coherent radio-frequency transceiver chains based on software radio Orthogonal Frequency Division Multiplex (OFDM) signaling...

Fifth generation cellular systems will be deployed in the microwave and millimeterwave (mmWave) frequency bands (i.e., between 0.5100 GHz). Propagation characteristics at these have a fundamental impact on each aspect of architecture, ranging from equipment design to real-time performance field. While we reasonable understanding propagation (<; 6 GHz) frequencies, same cannot said for mmWave. This article explains key differences mmWave bands, further gives examples how 5G system design.

The vehicle-to-vehicle (V2V) propagation channel has significant implications on the design and performance of novel communication protocols for vehicular ad hoc networks (VANETs). Extensive research efforts have been made to develop V2V models be implemented in advanced VANET system simulators evaluation. impact shadowing caused by other vehicles has, however, largely neglected most models, as well simulations. In this paper we present a shadow fading model targeting simulations based real...

This paper sets up a framework for designing massive multiple-input multiple-output (MIMO) testbed by investigating hardware (HW) and system-level requirements, such as processing complexity, duplexing mode, frame structure. Taking these into account, generic system partitioning is proposed, which allows flexible scaling distribution onto multitude of physically separated devices. Based on the given HW constraints maximum number links throughput peer-to-peer interconnections combined with...

Vehicle-to-vehicle (V2V) communication is an enabler for improved traffic safety and congestion control. As any wireless system, the ultimate performance limit determined by propagation channel. A particular point of interest shadowing effect large vehicles such as trucks buses, this might affect range significantly. In paper we present measurement results model channel, in which a bus acts either object or relay between two passenger cars. The setup based on Wireless Open-Access Research...

This paper provides an initial investigation on the application of convolutional neural networks (CNNs) for fingerprint-based positioning using measured massive MIMO channels. When represented in appropriate domains, channels have a sparse structure which can be efficiently learned by CNNs purposes. We evaluate accuracy state-of-the-art with channel fingerprints generated from model rich clustered structure: COST 2100 model. find that moderately deep achieve fractional-wavelength accuracies,...

This article aims at providing insights for a comprehensive understanding of terahertz (THz) propagation channels.Specifically, we discuss essential THz channel characteristics to be well understood the success communications.The methodology establishing realistic and 6G-compliant models based on measurements is then elaborated on, followed by discussion existing in literature.Finally, future research directions, challenges measures enrich channels are discussed.

Fourth-generation (4G) systems are expected to support data rates of the order 100 Mb/s in outdoor environment and 1 Gb/s indoor/stationary environment. In such large payloads, radio physical layer must employ receiver algorithms that provide a significant increase spectrum efficiency (and, hence, capacity) over current wireless systems. Recently, an explosion multiple-input-multiple-output (MIMO) studies have appeared with many journals presenting special issues on this subject. This has...