5G 3GPP-like Channel Models for Outdoor Urban Microcellular and Macrocellular Environments

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.Comment: To be published in 2016 IEEE 83rd Vehicular Technology Conference Spring (VTC 2016-Spring), Nanjing, China, May 201

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

Above-100 GHz wave propagation studies in the European project Hexa-X for 6G channel modelling

Abstract We describe capabilities and plans to characterize above 100 GHz radio channel and propagation effects as part of a 6G research project Hexa-X. The starting point is the existing knowledge of radio propagation gathered by prior measurement and theoretical studies. Then we define measurement equipment, planned or performed campaigns, and discuss some challenges related to measurements at upper mm-wave frequencies. For several reasons the channel measurements are more time consuming on higher frequencies and it is not easy to collect enough data for statistical analysis. Hence we briefly introduce a stored channel model that will be developed based on the gathered channel measurement data. This initial channel model can be used as it is for physical layer studies through simulations and also as a basis for future channel models

Analyses of beamspace MIMO channels at 142GHz

Abstract This paper presents the analyses of a single-user beamspace MIMO on measured indoor and outdoor channels at 142 GHz. The rank is evaluated under different antenna sizes, number of beams, and thresholds. We assume a total power constraint at the transmitter which results in a decrease in signal-to-noise ratio as the link distance increases. When using spatial multiplexing, the indoor and outdoor sites demonstrate an average capacity gain of 2x and 1.5x at link distances below 60 m. Also, the rank for our measured 142 GHz channels is comparable to that at 60 GHz channels but significantly lower than the rank at 5 GHz channels reported in the literature. We also found that at 142 GHz, the indoor and outdoor sites have median ranks of 3.0 and 1.7 for the small antenna case, and 4.9 and 2.4 for the large antenna case assuming a rank threshold of 20 dB. The indoor site has a rank higher by 1.8 than the outdoor site, regardless of antenna size. The rank decreases by only 20% and 15% for indoor and outdoor scenarios when beam density is halved, allowing a significant reduction in implementation complexity of the beamspace MIMO without remarkably reducing the rank

Out-of-band information aided mmWave/THz beam search:a spatial channel similarity perspective

Abstract The transition to higher frequency bands, e.g., millimeter-wave (mmWave) and terahertz (THz), will be capitalized on the long term for future wireless communications. One of challenges relates to rapid establishment of mmWave/THz links with low beam training overhead due to highly directional transmission. A promising solution is to take advantage of the coexistence of sub-6 GHz, mmWave, and THz wireless networks and to use out-of-band spatial information for enabling fast beam search. The success depends on the spatial similarity of radio channels across different frequency bands. In this article we promote a feasibility study of low-frequency spatial channel information assisted high-frequency beam search from a radio channel point of view. We develop multi-band channel similarity measure of desired beam directions extracted from radio channels, which are obtained via filtering propagation paths by different beampatterns at different frequencies. Measurementand ray-tracing-based evaluations across multiple frequencies and environments are performed, which prove the usability of out-of-band information aided beam search strategy in line-ofsight (LOS) dominated scenario and even in non-LOS scenario. Finally, we discuss the challenges associated with exploiting spatial channel similarity

On the feasibility of out-of-band spatial channel information for millimeter-wave beam search

Abstract Prolonged beam alignment is the main source of overhead in mobile wireless communications at millimeter-wave (mm-wave) frequencies due to narrow beams following the requirement of high antenna gains. Out-of-band spatial information may be used in initial beam search when lower frequency band radios are operating in conjunction with mm-wave radios. The feasibility of using low-band channel information for coarse estimation of high-band beam directions strongly depends on the spatial congruence between the two frequency bands. In this work, we try to answer two related questions. First, how similar is the power angular spectrum (PAS) of propagation channels between two widely separated frequency bands? Then, what is the impact of practical antenna configurations on spatial channel similarity? We propose a beam directions based metric to assess the power loss and number of false directions if out-of-band spatial information is used instead of in-band information. This metric is more practical and useful than comparing the PASs directly. Point cloud ray tracing and propagation measurement results across multiple frequency bands and environments are used to show that the degree of spatial similarity of beamformed channels is related to antenna beam widths, frequency gap, and radio link conditions

On the field emulation techniques in over-the-air testing:experimental throughput comparison

Abstract In this letter, we compare two field emulation techniques, namely plane-wave synthesis (PWS) and prefading signal synthesis (PFS) for multiple-input-multiple-output over-the-air (MIMO OTA) testing of mobile terminals in an anechoic chamber equipped with multiple probes. The comparison is performed in terms of measured throughput. The measurements were performed under urban microcellular scenario of the spatial channel model extended and at Long Term Evolution lower band 20. A practical mobile terminal is used as a test device. The throughput of four different browsing positions of the mobile terminal utilizing both emulation techniques has been measured. Results shows that at a fixed median throughput, the differences of the downlink channel power between the PFS and PWS techniques are small and are in the range of 0.2–1.0 dB for different browsing positions of the mobile terminal. The PWS and PFS techniques are equally capable of emulating the target field inside the test zone and are suitable for the MIMO OTA antenna testing based on anechoic chambers equipped with multiple probes

6G radio requirements to support integrated communication, localization, and sensing

Abstract 6G will be characterized by extreme use cases, not only for communication, but also for localization, and sensing. The use cases can be directly mapped to requirements in terms of standard key performance indicators (KPIs), such as data rate, latency, or localization accuracy. The goal of this paper is to go one step further and map these standard KPIs to requirements on signals, on hardware architectures, and on deployments. Based on this, system solutions can be identified that can support several use cases simultaneously. Since there are several ways to meet the KPIs, there is no unique solution and preferable configurations will be discussed