6G Vision, Value, Use Cases and Technologies from European 6G Flagship Project Hexa-X

While 5G is being deployed and the economy and society begin to reap the associated benefits, the research and development community starts to focus on the next, 6th Generation (6G) of wireless communications. Although there are papers available in the literature on visions, requirements and technical enablers for 6G from various academic perspectives, there is a lack of joint industry and academic work towards 6G. In this paper a consolidated view on vision, values, use cases and key enabling technologies from leading industry stakeholders and academia is presented. The authors represent the mobile communications ecosystem with competences spanning hardware, link layer and networking aspects, as well as standardization and regulation. The second contribution of the paper is revisiting and analyzing the key concurrent initiatives on 6G. A third contribution of the paper is the identification and justification of six key 6G research challenges: (i) “connecting”, in the sense of empowering, exploiting and governing, intelligence; (ii) realizing a network of networks, i.e., leveraging on existing networks and investments, while reinventing roles and protocols where needed; (iii) delivering extreme experiences, when/where needed; (iv) (environmental, economic, social) sustainability to address the major challenges of current societies; (v) trustworthiness as an ingrained fundamental design principle; (vi) supporting cost-effective global service coverage. A fourth contribution is a comprehensive specification of a concrete first-set of industry and academia jointly defined use cases for 6G, e.g., massive twinning, cooperative robots, immersive telepresence, and others. Finally, the anticipated evolutions in the radio, network and management/orchestration domains are discussed

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

How many beams does sub-THz channel support

| openaire: EC/H2020/101015956/EU//Hexa-XAntenna, radio frequency (RF) circuit, algorithm, and system researchers on sub-THz RF are interested in knowing characteristics of corresponding radio channels. Among other things, a relevant question is the number of beams supported by the channel. From wideband directional propagation measurements one can estimate how many significant paths are present in a measurement location, but interpreting that to separable beams is not trivial. In this letter, we introduce three methods to approximate the number of beams that a measured power angular delay profile can support. We show also example evaluations and distribution functions of beam numbers, estimated from indoor D-band measurement data.Peer reviewe

How many beams does sub-THz channel support

| openaire: EC/H2020/101015956/EU//Hexa-XAntenna, radio frequency (RF) circuit, algorithm, and system researchers on sub-THz RF are interested in knowing characteristics of corresponding radio channels. Among other things, a relevant question is the number of beams supported by the channel. From wideband directional propagation measurements one can estimate how many significant paths are present in a measurement location, but interpreting that to separable beams is not trivial. In this letter, we introduce three methods to approximate the number of beams that a measured power angular delay profile can support. We show also example evaluations and distribution functions of beam numbers, estimated from indoor D-band measurement data.Peer reviewe

On the Feasibility of Out-of-Band Spatial Channel Information for Millimeter-Wave Beam Search

| openaire: EC/H2020/101015956/EU//Hexa-XProlonged 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 the 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.Peer reviewe

A 38.5-to-60.5 GHz LNA with Wideband Combiner Supporting Cartesian Beamforming Architecture

Funding Information: ACKNOWLEDGMENT This research has been financially supported by Academy of Finland Ex5GRx (grant 2430226211) and also in part 6Genesis Flagship (grant 318927). Publisher Copyright: © 2021 IEEE.Current millimetre-wave (mmW) 5G NR standard supports multiple bands at 24.5/28/37/39/43/47GHz for communications. To cover several bands of the 5G NR and reaching lower end of unlicensed 60GHz band for 802.11ad, this work presents a wideband phased array front-end with LNA and two VGAs for scalar-only weighting function, and a wideband combining network of each signal weight in mmW domain for beamforming. In this work, two array elements are combined in two cascaded stages for extremely wideband operation. Combined load resonances are distributed and adjusted appropriately in each of the combining stages to achieve a flat response over the band of 38.5-60.5GHz. A single array path achieves rms gain of 8.5-12.5dB, noise figure of 6.2-8.1dB, and IP1dB of -33 to - 26dBm. The measurements show ≈ 6dB of array gain when the two phased array elements are combined in phase with +0.6dB to -0.4dB maximum gain error in the mmW VGAs. The prototype is implemented using 28nm CMOS.Peer reviewe

A Wideband IF Receiver Chip for Flexibly Scalable mmWave Subarray Combining and Interference Rejection

Large-scale multi-beam phased array systems suffer from inter-beam interference that should be canceled either in the analog or digital domain. In wideband systems such as fifth generation (5G), interference rejection over a wide bandwidth is challenging to achieve, not only due to non-idealities of the receiver chain but also due to the properties of the radio channel. This article presents a scalable inter-beam interference cancellation (IBIC) scheme at intermediate frequency (IF) using an IF receiver (IF-RX) chip. The IF-RX provides the flexibility of not just interference rejection between the subarrays but also wideband signal combining over multiple subarrays. It also provides wideband filtering before the analog-to-digital converter (ADC) to support 5G channel bandwidths of up to 800 MHz, high linearity and low noise figure. A calibration method is proposed to find the cancellation coefficients for the IF receiver in measurements. Furthermore, a simplified over-the-air (OTA) IBIC model for analyzing rejection bandwidth limitations is presented. Interference rejection performance is demonstrated through the OTA measurements using 5G new radio (5G NR) signals. In the OTA measurements, 34–37-dB of rejection was achieved for 50–100-MHz signals, while error vector magnitude (EVM) requirements of the 5G standards were met with good margins. Finally, the interference rejection over 4ˆ100 MHz carrier aggregated 5G NR waveform was demonstrated

Innovation Management in 6G research: the case of Hexa-X project

International audienceVery often in the past, innovations from research communities have been disconnected from industry adoption, leading to a lack of exploitation of research projects. Toovercome this issue, in the view of future 6G systems, the HexaX project is putting in place an Innovation Management (IM) process, aiming to facilitate and promote innovation opportunities based on project outcomes and ensure that all the ideas emerging from the project are captured and tracked, not "lost". Focus of IM is on supporting the project to promptlyidentify innovations and engage with emerging innovation needs in the sector, for identifying gaps and potentials with strategic value. This paper presents the IM approach in Hexa-X and the main innovations (awarded by the EC Innovation Radar), with particular emphasis on the technical aspects of these findings coupled with their identified strategic value for future 6G market exploitation

6G Radio Requirements to Support Integrated Communication, Localization, and Sensing

| openaire: EC/H2020/101015956/EU//Hexa-X Funding Information: ACKNOWLEDGMENT This work was supported, in part, by the European Commission through the H2020 project Hexa-X (Grant Agreement no. 101015956) and the MSCA-IF grant 888913 (OTFS-RADCOM).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.Peer reviewe