This paper presents key parameters including the line-of-sight (LOS) probability, large-scale path loss, and shadow fading models for the design of future fifth generation (5G) wireless communication systems in urban macro-cellular (UMa) scenarios, using the data obtained from propagation measur ements at 38 GHz in Austin, US, and at 2, 10, 18, and 28 GHz in Aalborg, Denmark. A comparison of different LOS probabilit y models is performed for the Aalborg environment. Alpha-betagamma and close-in reference distance path loss models are studied in depth to show their value in channel modeling. Additionally, both single-slope and dual-slope omnidirectional path loss models are investigated to analyze and contrast th eir root-mean-square (RMS) errors on measured path loss values . While the results show that the dual-slope large-scale pathloss model can slightly reduce RMS errors compared to its singleslope counterpart in non-line-of-sight (NLOS) conditions, the improvement is not significant enough to warrant adopting the dual-slope path loss model. Furthermore, the shadow fading magnitude versus distance is explored, showing a slight inc reasing trend in LOS and a decreasing trend in NLOS based on the Aalborg data, but more measurements are necessary to gain a better knowledge of the UMa channels at centimeterand millimeter-wave frequency bands.

This paper presents and compares two candidate large-scale propagation path loss models, the alpha-betagamma (ABG) model and the close-in (CI) free space reference distance model, for the design of fifth generation (5G) wireless communication systems in urban microand macro-cellular scenarios. Comparisons are made using the data obtained fro m 20 propagation measurement campaigns or ray-tracing studi es from 2 GHz to 73.5 GHz over distances ranging from 5 m to 1429 m. The results show that the one-parameter CI model has a very similar goodness of fit (i.e., the shadow fading standard deviation) in both line-of-sight and non-line-of-sight environments, while offering substantial simplicity and more stable behavior across frequencies and distances, as compa red to the three-parameter ABG model. Additionally, the CI model needs only one very subtle and simple modification to the exis t ng 3GPP floating-intercept path loss model (replacing a consta nt with a close-in free space reference value) in order to provi de greater simulation accuracy, more simplicity, better repeatability across experiments, and higher stability across a vast rang e of frequencies. I. I NTRODUCTION The rapid growth of personal communication devices such as smart phones and tablets, and consumer demand for ubiquitous data access, have motivated carriers to provide higher data rates and quality. Innovative technologies and new frequen cy bands such as millimeter waves (mmWaves) are needed to meet this impending demand [1], driving the development of the fifth generation (5G) wireless communications [ ?]. Emerging 5G communication systems are expected to introduce revolutionary technologies, while utilizing potenti al new spectra and novel architectural concepts [2], [3], hence it is critical to develop new standards and channel models to assist engineers in system design. Channel characterizati on t mmWave frequencies has been conducted by prior researchers . Violette et al. studied wideband non-line-of-sight (NLOS) channels at 9.6, 28.8, and 57.6 GHz in downtown Denver [4]; Outdoor propagation measurements and modeling at the 60 GHz band were carried out in various city streets [5], [6]; Samsung has been active in measuring and modeling mmWave channels for future mobile communications [7], [8]; Channel measurements at 81 GHz to 86 GHz of the E-band were performed by Aalto University for point-topoint communications in a street canyon scenario in Helsink i, Finland [9]; Extensive propagation measurements have been performed at 28 GHz, 38 GHz, and 73 GHz in urban microcellular (UMi), urban macro-cellular (UMa), and/or indoor scenarios [1], [10], [11], from which spatial and temporal statistics were extracted in combination with the ray-trac ing technique. Omnidirectional path loss models in dense urban environments at 28 GHz and 73 GHz were investigated in [12]. There are numerous other measurement campaigns throughout the world at mmWave frequencies that are being or have just been performed and have not yet been published, such as the measurement data provided in this paper. This paper presents the alpha-beta-gamma (ABG) and close-in (CI) free space reference distance path loss model s [13]–[15] at mmWave frequencies, and provides a head-tohead comparison between the parameters and shadow fading (SF) standard deviations in these two models in both UMi and UMa scenarios, using 20 sets of measurement or ray-tracing data contributed by New York University (NYU), Nokia, Aalborg University (AAU), Qualcomm, and Aalto University. II. CLOSE-IN REFERENCEDISTANCE AND ALPHA-BETA-GAMMA PATH LOSSMODELS Both ABG and CI path loss models are generic allfrequency models that describe large-scale propagation pa th loss at all relevant frequencies in a certain scenario. The C I model is easily implemented in existing 3GPP models by making a very subtle modification — by replacing a floating non-physically based constant with a frequency-dependent constant that represents free space path loss in the first met er of propagation. The equation for the ABG model is given by (1): PL(f, d)[dB] =10αlog10 (

For the development of new 5G systems to operate in bands up to 100 GHz, there is a need for accurate radio propagation models at these bands that currently are not add ressed by existing channel models developed for bands below 6 GHz. T his document presents a preliminary overview of 5G channel mode ls for bands up to 100 GHz. These have been derived based on extensive measurement and ray tracing results across a mult itude of frequencies from 6 GHz to 100 GHz, and this document describe s an initial 3D channel model which includes: 1) typical deployment scenarios for urban microcells (UMi) and urban macrocells ( UMa), and 2) a baseline model for incorporating path loss, shadow f ading, line of sight probability, penetration and blockage models for the typical scenarios. Various processing methodologies s uch as clustering and antenna decoupling algorithms are also pres ented.

This paper compares three candidate large-scale propagation path loss models for use over the entire microwave and millimeter-wave (mmWave) radio spectrum: the alpha-betagamma (ABG) model, the close-in (CI) free-space reference distance model, and the CI model with a frequency-weighted path loss exponent (CIF). Each of these models has been recently studied for use in standards bodies such as 3rd Generation Partnership Project (3GPP) and for use in the design of fifth-generation wireless systems in urban macrocell, urban microcell, and indoor office and shopping mall scenarios. Here, we compare the accuracy and sensitivity of these models using measured data from 30 propagation measurement data sets from 2 to 73 GHz over distances ranging from 4 to 1238 m. A series of sensitivity analyses of the three models shows that the four-parameter ABG model underpredicts path loss when relatively close to the transmitter, and overpredicts path loss far from the transmitter, and that the physically based two-parameter CI model and three-parameter CIF model offer computational simplicity, have very similar goodness of fit (i. e., the shadow fading standard deviation), exhibit more stable model parameter behavior across frequencies and distances, and yield smaller prediction error in sensitivity tests across distances and frequencies, when compared to the four-parameter ABG model. Results show the CI model with a 1-m reference distance is suitable for outdoor environments, while the CIF model is more appropriate for indoor modeling. The CI and CIF models are easily implemented in existing 3GPP models by making a very subtle modification-by replacing a floating non-physically based constant with a frequency-dependent constant that represents free-space path loss in the first meter of propagation. This paper shows this subtle change does not change the mathematical form of existing ITU/3GPP models and offers much easier analysis, intuitive appeal, better model parameter stability, and better accuracy in sensitivity tests over a vast range of microwave and mmWave frequencies, scenarios, and distances, while using a simpler model with fewer parameters.

With the standardization of 5G cellular systems now underway, new frequency bands are being considered for 5G deployments, namely, cmWave bands (3-30 GHz) and mmWave bands (30-100 GHz). An early use case for 5G in these non-traditional cellular bands is to provide fixed access wireless services to residential users in suburban neighborhoods. In this paper, we present a massive MIMO system concept for providing high data rate fixed wireless services in the suburban microcellular environment in the 28 GHz band. The MIMO system concept leverages relatively simple methodologies that can be deployed relatively quickly to enable fast introduction of 5G-like services. We investigate the impact on performance of several key system design aspects and various environmental effects. We leverage a recently-developed channel model for suburban microcellular deployments operating in the cmWave and mmWave bands. The purpose is demonstrate the performance of these relatively simple solutions, provide answers to some key design questions, and show the viability of providing high data rate broadband services in residential suburban environments in the cmWave and mmWave bands.

The use of high-frequency millimeter wave (mmWave) bands for 5G communication systems has received much attention over the last few years. Analog-to-digital converters (ADCs) contribute significantly to the implementation cost and power consumption of wireless receivers. The use of large antenna arrays in mmWave communications causes these costs to rise even further. Using low precision quantizers in ADCs can reduce these costs significantly. In this paper, we propose a novel receiver design using low precision quantizers drawing ideas from the parallel ADC design literature. Utilizing structural similarities between multi-antenna receivers and parallel ADCs, we show that the signal-to-noise ratio and achievable rate, respectively, scale linearly and logarithmically with the number of antennas. We also extend the idea to the scenario where multiple streams can be transmitted simultaneously. Our simulations of the receiver show promising bit error rate performance under different scenarios and also show how error control coding can be incorporated to improve performance. All our designs depend only on symbol rate sampling, which eliminates costly oversampling of high bandwidth signals.

One important deployment case for 5G will be as an alternative to fiber to the home. The result is that a significant number of 5G deployments will be in a suburban setting, referred to as the suburban micro (SMi) environment in this paper. This SMi environment will be characterized by access points (APs) located on lamp or utility poles at heights no greater than around 8 m and user equipment (UE) being located inside or outside of a home. The suburban setting is quite different from the urban micro (UMi) or urban macro (UMa) environments in that foliage will play a very significant role and buildings are dominated by one to two story homes instead of multi-story apartment and office buildings. Unfortunately existing channel models, particularly the new 3GPP channel model from 6 to 100 GHz, are designed for environments other than SMi. In this paper we propose a preliminary channel model for the SMi environment, targeted for frequencies from 1-100 GHz, derived from a ray tracing study in Arlington Heights, IL. As part of the proposed model, three different foliage conditions are studied so that users of the model can choose a foliage condition that best matches the environment they would like to study.

It is becoming clear that 5G wireless systems will encompass frequencies from around 500 MHz all the way to around 100 GHz. To adequately assess the performance of 5G systems in these different bands, path loss (PL) models will need to be developed across this wide frequency range. The PL models can roughly be broken into two categories, ones that have some anchor in physics, and ones that curve- match only over the data set without any physical anchor. In this paper we use both real-world measurements from 2 to 28 GHz and ray-tracing studies from 2 to 73.5 GHz, both in an urban-macro environment, to assess the prediction performance of the two PL modeling techniques. In other words, we look at how the two different PL modeling techniques perform when the PL model is applied to a prediction set which is different in distance, frequency, or environment from a measurement set where the parameters of the respective models are determined. We show that a PL model with a physical anchor point can be a better predictor of PL performance in the prediction sets while also providing a parameterization which is more stable over a substantial number of different measurement sets.

Future mobile communications systems are likely to be very different to those of today with new service innovations driven by increasing data traffic demand, increasing processing power of smart devices and new innovative applications. To meet these service demands the telecommunications industry is converging on a common set of 5G requirements which includes network speeds as high as 10 Gbps, cell edge rate greater than 100 Mbps, and latency of less than 1 msec. To reach these 5G requirements the industry is looking at new spectrum bands in the range up to 100 GHz where there is spectrum availability for wide bandwidth channels. For the development of new 5G systems to operate in bands up to 100 GHz there is a need for accurate radio propagation models which are not addressed by existing channel models developed for bands below 6 GHz. This paper presents a preliminary overview of the 5G channel models for bands up to 100 GHz in indoor offices and shopping malls, derived from extensive measurements across a multitude of bands. These studies have found some extensibility of the existing 3GPP models (e.g. 3GPP TR36.873) to the higher frequency bands up to 100 GHz. The measurements indicate that the smaller wavelengths introduce an increased sensitivity of the propagation models to the scale of the environment and show some frequency dependence of the path loss as well as increased occurrence of blockage. Further, the penetration loss is highly dependent on the material and tends to increase with frequency. The small-scale characteristics of the channel such as delay spread and angular spread and the multipath richness is somewhat similar over the frequency range, which is encouraging for extending the existing 3GPP models to the wider frequency range. Further work will be carried out to complete these models, but this paper presents the first steps for an initial basis for the model development.

This paper presents and compares two candidate large-scale propagation path loss models, the alpha-beta-gamma (ABG) model and the close-in (CI) free space reference distance model, for the design of fifth generation (5G) wireless communication systems in urban micro- and macro-cellular scenarios. Comparisons are made using the data obtained from 20 propagation measurement campaigns or ray-tracing studies from 2 GHz to 73.5 GHz over distances ranging from 5 m to 1429 m. The results show that the one-parameter CI model has a very similar goodness of fit (i.e., the shadow fading standard deviation) in both line-of-sight and non-line-of-sight environments, while offering substantial simplicity and more stable behavior across frequencies and distances, as compared to the three-parameter ABG model. Additionally, the CI model needs only one very subtle and simple modification to the existing 3GPP floating-intercept path loss model (replacing a constant with a close-in free space reference value) in order to provide greater simulation accuracy, more simplicity, better repeatability across experiments, and higher stability across a vast range of frequencies.

For the development of new 5G systems to operate in bands up to 100 GHz, there is a need for accurate radio propagation models at these bands that currently are not addressed by existing channel models developed for bands below 6 GHz. This document presents a preliminary overview of 5G channel models for bands up to 100 GHz. These have been derived based on extensive measurement and ray tracing results across a multitude of frequencies from 6 GHz to 100 GHz, and this document describes an initial 3D channel model which includes: 1) typical deployment scenarios for urban microcells (UMi) and urban macrocells (UMa), and 2) a baseline model for incorporating path loss, shadow fading, line of sight probability, penetration and blockage models for the typical scenarios. Various processing methodologies such as clustering and antenna decoupling algorithms are also presented.

Over the last two decades, multiple-input, multiple-output (MIMO) technology has been successfully deployed on a wide scale in cellular communication systems. MIMO technology involves the use of multiple antennas at one or both ends of a communication link to boost the performance and reliability through strategies such as beamforming, diversity transmission, spatial multiplexing, and interference suppression. The currently-deployed 4G/LTE cellular standards (LTE Rel-8/9/10) support a comprehensive suite of MIMO techniques for up to eight antenna ports in a single sector on the downlink and up to four transmit antennas at a mobile station. For 5G cellular communications, massive MIMO, sometimes called full dimension MIMO, is a promising technology for enhancing system performance for frequency bands ranging from under 6 GHz to 100 GHz. Also, for 5G systems deployed in higher frequency bands such as cmWaves (6–30 GHz) and mmWaves (30–100GHz), large-scale antenna arrays will be a prerequisite for overcoming the poor propagation characteristics in those bands. This chapter will describe the basics of massive MIMO and how it will satisfy the high-data-rate demands of 5G cellular systems for frequency bands up to 100 GHz. The current state of the art of MIMO technology are reviewed, and the application of large-scale antenna arrays to 5G are described. The chapter also surveys current trends in massive MIMO technology and system concepts, with a focus on methodologies for significantly enhancing cellular system performance. Various trends and promising concepts are identified, and various practical issues highlighted.

This paper presents key parameters including the line-of-sight (LOS) probability, large-scale path loss, and shadow fading models for the design of future fifth generation (5G) wireless communication systems in urban macro- cellular (UMa) scenarios, using the data obtained from propagation measurements at 38 GHz in Austin, US, and at 2, 10, 18, and 28 GHz in Aalborg, Denmark. A comparison of different LOS probability models is performed for the Aalborg environment. Alpha-beta-gamma and close-in reference distance path loss models are studied in depth to show their value in channel modeling. Additionally, both single-slope and dual-slope omnidirectional path loss models are investigated to analyze and contrast their root-mean-square (RMS) errors on measured path loss values. While the results show that the dual-slope large-scale path loss model can slightly reduce RMS errors compared to its single-slope counterpart in non-line-of-sight (NLOS) conditions, the improvement is not significant enough to warrant adopting the dual- slope path loss model. Furthermore, the shadow fading magnitude versus distance is explored, showing a slight increasing trend in LOS and a decreasing trend in NLOS based on the Aalborg data, but more measurements are necessary to gain a better knowledge of the UMa channels at centimeter- and millimeter-wave frequency bands.

Fifth-generation wireless systems are expected to employ multiple-antenna communication at millimeter wave (mm Wave) frequencies using small cells within heterogeneous cellular networks. The high path loss of mm Wave and the physical obstructions make communication challenging. To compensate for the severe path loss, mm Wave systems may employ a beam alignment algorithm that facilitates highly directional transmission by aligning the beam direction of multiple antenna arrays. This paper discusses a mm Wave system employing dual-polarized antennas. First, we propose a practical soft-decision beam alignment (soft-alignment) algorithm that exploits orthogonal polarizations. By sounding the orthogonal polarizations in parallel, the equality criterion of the Welch bound for training sequences is relaxed. Second, the analog beamforming system is adapted to the directional characteristics of the mm Wave link, assuming a high Ricean K-factor and poor scattering environment. A soft-alignment algorithm enables the mm Wave system to align a large number of narrow beams to the channel subspace in an attempt to effectively scan the mm Wave channel. Third, we propose a method to efficiently adapt the number of channel sounding observations to the specific channel environment based on an approximate probability of beam misalignment. Simulation results show that the proposed soft-alignment algorithm with adaptive sounding time effectively scans the channel subspace of a mobile user by exploiting polarization diversity.

Operating at higher frequencies, and in particular the millimeter wave (mmWave) frequency of 72 GHz poses various challenges to the RF hardware. One of these particular RF challenges is the phase noise (PN) created by the local oscillators (LOs) which is made worse by upbanding (i.e., multiplication by some factor) the LO to reach the desired frequency. The result of this relatively large PN is that in block-processing systems such as frequency-domain equalization for single carrier, there will be an unknown phase value which changes from block to block. Thus even if the channel itself does not change from one block to another, there would be one unknown phase value which needs to be tracked. In this paper we explore existing and propose new blind methods for tracking the PN in a null cyclic prefix single-carrier communication system. The methods are designed for BPSK and QAM constellations and are seen in simulations to have better performance than pilot-assisted tracking.