F eb 2 01 6 Propagation Path Loss Models for 5 G Urban Micro-and Macro-Cellular Scenarios

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 (