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TR 38.807RAN
Study on Requirements for NR beyond 52.6 GHz

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WI Acronym:  FS_NR_beyond_52GHz
Rapporteur:  Dr. Kwon, EddyIntel Corporation (UK) Ltd

This document provides uses cases and deployment scenarios for NR system operation in carriers between 52.6 GHz and 100 GHz and also provide operational and system design requirements, which can facilitate 3GPP's future enhancements to NR beyond 52.6GHz. NR physical layer channels in Release 15 were designed to be optimized for uses under 52.6 GHz and with the potential to be used for above 52.6 GHz.
However, frequencies above 52.6 GHz are faced with more difficult challenges, such as higher phase noise, extreme propagation loss due to high atmospheric absorption, lower power amplifier efficiency, and strong power spectral density regulatory requirements, compared to lower frequency bands. Additionally, the frequency ranges above 52.6 GHz potentially contain larger spectrum allocations and larger bandwidths that are not available for bands lower than 52.6 GHz and should support widely ranging use cases, such as V2X, IAB, NR licensed and unlicensed, and non-terrestrial operations.
With the aim of enabling and optimizing 3GPP NR systems for operation in above 52.6 GHz, as originally planned during the NR SI (TR 38.913), 3GPP should further work on physical layer channels including potential introduction of new waveform, procedures, and requirements, etc., where the operation is applicable for operations in licensed and unlicensed spectrum, to WAN operation, private networks, Integrated Access Backhaul (IAB), ITS application using vehicular communications (V2X), etc.
The objective of the TD RP-181435 study item are the following:
  • identify target spectrum ranges, including survey on global spectrum availability, regulatory requirements, channelization, and licensing regimes,
  • identify potential use cases and deployment scenarios,
  • identify NR design requirements and considerations on top of regulatory requirements.

full Table of Contents for  TR 38.807  Word version:   16.0.0

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1  ScopeWord-p. 6
2  References
3  Definitions, symbols and abbreviationsWord-p. 9
4  Operational RequirementsWord-p. 11
4.1  Overview of Global Spectrum Availability
Within the range 52.6 to 116 GHz, the frequency bands 66-76 GHz (including 66-71 and 71-76 GHz) and 81-86 GHz are being studied under WRC-19 Agenda Item 1.13 for potential IMT identification. Results of sharing and compatibility studies, potential technical and regulatory conditions are included in Draft CPM Report [6], and the final decisions are to be made in WRC-19 with respect to IMT identification or no IMT identification, along with the corresponding technical and regulatory conditions.
For 66-71 GHz, Studies were carried out for the ISS, MSS (Earth-to-space) indicating that sharing is feasible, with a need for separation distance in the order of few kilometers for the case of MSS (space-to-Earth). The need for studies addressing interference from IMT towards RNS is still under debate. Thus, final conclusions in the regulatory and technical conditions for this band cannot be drawn.
For 71-76 GHz, studies were carried out for the FS, RLS and FSS (space-to-Earth) indicating that sharing with FS and FSS is feasible. However, additional limits of the IMT BS and UE unwanted emissions is needed to protect RLS in the adjacent frequency band 76-81 GHz.
For 81-86 GHz, studies were carried out for the FS, FSS (Earth-to-space), RAS (in band and adjacent band), EESS (passive) and RLS. Studies are not needed for the SRS (passive), as this service is dealing with sensors around other planets and no interference issue is expected. Studies were also not carried out for the MSS. The results of those studies indicate that sharing with FS, FSS and RAS (in band and adjacent band) is feasible. Notice that additional limits of the IMT BS and UE unwanted emissions would be needed to ensure protection of EESS (passive) in the adjacent frequency band 76-81 GHz and RLS in the adjacent frequency band 86-82 GHz.
4.2  Country Specific Spectrum Availability and Spectrum Regulatory RequirementsWord-p. 13
5  Use Cases and Deployment ScenariosWord-p. 52
5.1  Use Cases
The relatively underutilized millimeter-wave (mmWave) spectrum offers excellent opportunities to provide high speed data rate, low latency, and high capacity due to the enormous amount of available contiguous bandwidth. However, operation on bands in frequencies above 52.6GHz will be limited by the performance of devices, for example, poor power amplifier (PA) efficiency and larger phase noise impairment, the increased front-end insertion loss together with the low noise amplifier (LNA) and analog-to-digital converter (ADC) noise. In addition, bands in frequencies above 52.6GHz have high propagation and penetration losses challenge. Even so, various use cases are envisioned for NR operating in frequencies between 52.6GHz and 114.25GHz.
5.1.1  High data rate eMBBWord-p. 53
The use case serves high-definition multimedia and high user density by cellular network, which will increase in many indoor and outdoor open areas, such as stadium, main event for entertainment, sport and so on; and media delivery will be both to individuals and to groups of users. Moreover, user devices will get enhanced media consumption capabilities, such as Ultra-High Definition display, multi-view High Definition display, mobile 3D projections, immersive video conferencing, and augmented reality and mixed reality display and interface. This will all lead to a demand for significantly higher data rates and wide bandwidth from 52.6GHz to 114.25 GHz.
5.1.2  Mobile data offloadingWord-p. 54
The use of complementary network technologies, such as NR-U, with much wider spectrum for delivering data originally targeted for cellular networks, which has met heavily traffic load, in both indoor and outdoor open area eMBB usage scenario. Operators may leverage bands to offload data from macro cell at hot spots. In such scenarios, high band may be dual connectivity (DC) or carrier aggregation (CA) with low band for mobility purposes. Coverage for this scenario may not be chosen as optimization target.
Given that more than 10GHz of bandwidth is available for short range communications in unlicensed spectrum above 52.6GHz, UEs could significantly mitigate eMBB data congestion with use of these spectrum. Users requiring enhanced media reception in hotspot areas or utilizing other high bandwidth applications in hotspot areas could be serviced with available licensed or unlicensed spectrum without impacting network load in lower frequencies.
5.1.3  Short-range high-data rate D2D communicationsUp
Wireless docking at office has attracted much interest for future wireless office environment. For wireless application at smart home and office meeting, data transmission from UE to large screen or projector also needs energy efficient transmission mechanisms. Bands above 52.6GHz provide great potential for such low latency and high data rate transmission.
Productivity docking, such as Monitor 8K UHD docking, is one of the typical short-range high-data rate D2D use case. The directional transmission, which results in highly local beam characteristics, and high capacity from wide bandwidths can satisfy the requirement of this use case. Additionally, due to high pathloss, NFC-like use cases including personal identification, digital key, wireless USB, and cable-free are suitable. This service requires high capacity and low latency to exchange security data or encrypted data between devices.
Wireless display transfer to smart TVs, augmented reality (AR), virtual reality (VR) headsets, monitors, and video distribution screens (e.g. screens/monitors at in-flight entertainment, classrooms, high-speed rail, exhibitions, etc) can be performed using licensed/unlicensed spectrum.
In today's home, office and factory, there are lots of cables between devices (e.g., the HDMI cables between the monitors and set-top boxes, cables to connect racks and cabinets in data centers) to provide very high data rate connection. Due to the capability of providing high speed data transmission, frequency band above 52.6GHz can also be used for this kind of high speed D2D connection, and this cable-less high speed connection is promising to enable new smart home/office/factory applications.
5.1.4  Vertical industry factory applicationWord-p. 55
There is not only a single class of services, but there are various services of different requirement need to support in this use case: such as motor control, mobile control, motor robot, Augmented Reality (AR), and etc, thus resulting in the need for a high adaptability and scalability of the system. Some services of industrial-grade quality have stringent requirements in terms of end-to-end latency, communication service availability and jitter, and some services, such as AR, requires high data rate transmission, high reliability, and low latency, and some applications have stringent requirements on safety, security, and privacy. The millimeter wave technique is quite suited for vertical industry application networks or other private/security networks due to its highly local characteristic and wide bandwidth.
5.1.5  Broadband distribution network
Today, wireless Ethernet networks (a.k.a. 802.11 based) offer broadband connectivity to confined outdoor venues such as university campuses, stadiums, malls etc. When operating in carrier frequency above 52.6GHz NR should offer feature parity (if not exceed) to such wireless Ethernet based networks to serve either as replacement or complimentary network. Here, the expectation is for a single node (e.g. gNB) to offer broadband service (in order of roughly above 20Gbps) to a few fixed (non-mobile) devices (e.g. UE) over a distance of approximately 300m to 500m. The resulting network could either be public or non-public. Both point to point, and point-to-multipoint transmissions should be supported.
The last mile distribution of wideband internet access (e.g. fiber) using fixed wireless licensed/unlicensed spectrum available for above 52.6 GHz could be useful. Backhauling of wireless to the home/building/curb/neighborhood (WTTx) distribution networks would require high data rates to be supported in both downlink and uplink. The access nodes could be specialized UE that enables home/building networking via Wi-Fi or Ethernet networks, or could be an Integrated Access Backhaul (IAB) that enables NR using either licensed or unlicensed spectrum within the home/building area.
5.1.6  Integrated access backhaul (IAB)Word-p. 56
The use case mainly is applied for backhauling deployment when optical or dedicated wireless backhaul is unavailable or inconvenient. Such backhauling can take advantage from the currently developed NR Integrated Access Backhaul (IAB), where some nodes serve both backhaul and access. In this use case, devices operate with LOS under most conditions, though obstruction of the LOS may occur occasionally, so directional transmission can extend the distance between the gNBs.
There are already lots of commercial deployments of backhaul applications using the bands above 52.6GHz. Compared with the lower frequency bands, the abundance of available spectrum can support higher capacity for both wireless access link and backhaul link. Low latency requirement can also be satisfied by NR flexible frame structure.
Where a wired connection is not a feasible option, various wireless technologies e.g. point to point (PTP) microwave links are used to offer backhaul / relay service. 3GPP Rel-16 offers backhaul / relay service under the IAB umbrella. However, this service is presently limited to carrier frequency below 52.6GHz. NR operating in carrier frequency above 52.6GHz NR should extend such capabilities to this higher frequency range. Here, the expectation is for a single node (e.g. gNB) to offer broadband services to a few devices (e.g. UE) or to offer relay services (up to certain hops) to a few devices (e.g. other nodes) or a combination thereof. The expected coverage range is approximately 300m to 500m.
5.1.7  Factory automation/Industrial IoT (IIoT)Word-p. 57
This set of use-cases is expected to target indoor industrial automation applications over a distance of approximately 50 to 100m, with speed below 5km/hr, and other characteristics such as latency, and packet error rate in accordance with performance requirements mentioned in Clause 7 of TS 22.261.
Industrial IoT is one of the key enablers of cost-efficient industrial mass production with high quality in factory automation. In the factories of the future, static sequential production systems will be more and more replaced by novel modular production systems offering a high flexibility and versatility. This involves a large number of increasingly mobile production assets, for which powerful wireless communication and localization services are required. The corresponding applications are often characterized by very high requirements on the underlying connectivity of the infrastructure, especially in terms of latency and reliability. High resolution time synchronization, low delay jitter, guaranteed delay constraints are important characteristics of industrial IoT operations.
The challenge with indoor-to-outdoor dampening in millimeter wave bands will, in these scenarios, become a benefit as the band offers good isolation from/to outside world. In such scenarios, controlled interference and the wide spectrum can be utilized to meet high reliability and low latency in a factory.
5.1.8  Augmented reality/virtual reality headsets and other high-end wearablesWord-p. 58
For high-end augmented reality or virtual reality wearables like glasses, they typically demand large data rate and low transmission power. For AR/VR application, due to small latency requirement, those video may not be compressed and thus require larger than 10Gbps data rate. They may also have low transmission power since high transmission power would require large battery and increase weight of the wearable. Additionally, augmented reality relies on substantial sensor information to process and resolve the environment. The higher bandwidths may improve both sensor resolution and reduce latency.
5.1.9  Intelligent Transport Systems (ITS) and V2X
ITS supports transportation of good and humans in order to efficiently and safely use transport infrastructure and transport means. Wireless connectivity for inter-vehicle and vehicle to roadside communication applications was deemed suitable to be operated in frequencies above 52.6GHz. These networks operate over a short range with very wideband communications using a variety of directional medium and high gain antennas to enable a high degree of spectrum reuse, and may use a flexible bandwidth scheme under which they normally operate in a wideband mode, and periodically reduce their bandwidth (e.g. for antenna training and other activities). The wide millimeter wave spectrum can be exploited for providing low latency, high reliability, and often high data requirements in various short range ITS and V2X scenarios.
Extended sensors: this service enables the exchange of raw/processed data gathered through local sensors or live video data among vehicles, pedestrians, and V2X application servers. This service helps vehicles to enhance the perception of their environment beyond what their own sensors can detect. This leads to a more holistic view of their local situation.
Precise positioning for automated driving: automated driving systems require highly resolved and dynamic maps to maneuver the vehicles safely, in particular as a means of providing decimeter localization which is not achieved by typical consumer-grade satellite navigation equipment. Exchanging high definition (HD) dynamic map information between vehicles is required to widen the visibility area of HD maps to enhance positioning accuracy. The V2V/V2X communication targeting automated driving requires high data rate, low latency, and high reliability within a communication range of 150m to 300m, which can be done in millimeter wave.
5.1.10  Data Center Inter-rack ConnectivityWord-p. 59
Wireless connectivity may be used as a secondary interface in lieu of fiber optic failure for links between racks within a data center. A backup network relying on wireless technology can be used to increase maximum communication service availability. Some inter-rack links could be replaced with high bandwidth and high reliable NR communications. Although use of unlicensed spectrum could be possible, due to high bandwidth and reliability required for inter-rack communications use of licensed spectrum, which typically has higher EIRP allowance, could be useful. The use of wireless communications for some links within the data center, could potentially reduce cabling complexity and allow flexible on-demand re-organization of equipment within the facility.
5.1.11  Smart grid automation
Electricity distribution possesses high requirements on service availability. In power distribution system, while lower frequencies are more suitable for long distance wireless inter-substation communication, short range intra-substation wireless communication can be performed in millimeter wave.
5.1.12  Radar/Positioning
High positioning accuracy (e.g., error standard deviations of 0.5m or lower) in both outdoor and indoor deployments services are critical. Unlike lower carrier frequencies, where transmission is position agnostic, in millimeter wave carrier frequencies, positioning information is required to avoid blocking. In addition, positioning information can also enhance the process of beam alignment. Beam-related information can be used to localize a user within a beam or within the intersection of multiple beams, or to enhance positioning accuracy of existing position systems. In addition, applications that require high positioning accuracy can benefit from a wide bandwidth, which facilitates accurate estimation of the time of arrival (ToA) of signals. Also, the multipath sparsity characteristic of millimeter wave channels, together with narrow beam antenna systems, contribute to improve angle of arrival (AoA) estimation, which can in turn be used to enhance the positioning accuracy.
Radar-like operations (motion detection, positioning, and tracking) integrated together with access point can provide wide range of services including security, medical care, and automation.
In automated factories, powerful wireless localization services are often required for low speed moving objects (including indoor and outdoor), which can be performed in millimeter wave systems. For example, on the factory floor, it is desirable to be able to locate moving objects such as forklifts, or parts to be assembled. This could be achieved with positioning and/or environmental sensing. Environmental sensing is support for radar applications identifying objects in the environment and their respective motion. Use of millimeter wave carrier frequency may allow radar operations that may be useful for various network operations. Indoor spaces and dense deployments will benefit from greater spatial resolution allowing operators and private networks to offer new targeted services and solutions.
5.1.13  Private NetworksWord-p. 60
Enable easy and cost-effective deployment of industrial private networks including non-public and closed group access, allowing regional deployment of closed or semi-closed access such as industrial IoT, in-building network, and factory areas.
5.1.14  Critical medical communication
As described in TR 22.826, various critical medical use cases require very high data rates and very low latencies. The huge bandwidths offered by 5G NR above 52.6 GHz could prove to be essential in order to meet the required KPIs. One of the primary examples includes a wirelessly connected operating room that enables real-time streaming of lossless compressed Ultra High Definition video (from devices, such as an endoscope), and real-time streaming of uncompressed medical imaging data (from devices, such as 3D UltraSound). These streams need to be displayed on 4K/8K displays, and possibly be combined into augmented reality video streams to help a surgeon perform precise procedures. This typically requires datarates ranging from 4 Gbit/s up to 48 Gbit/s and very low latencies of preferably less than 1ms. Compression is often not allowed by medical regulations, in order to not generate any artifacts and enable the most accurate representation to be available to a surgeon.
Despite the low latency and high datarates required, medical data in general needs to be transported in a highly secure manner, including being fully integrity protected as required by medical data protection and privacy regulations. And of course, the connection has to be highly reliable and very robust.
5.2  Deployment Scenarios
5.2.1  Indoor hotspotWord-p. 61
The indoor hotspot deployment scenario focuses on small coverage per site/TRxP (transmission and reception point) and high user throughput or user density in buildings. The key characteristics of this deployment scenario are high capacity, high user density and consistent user experience indoor.
5.2.2  Dense urban
The dense urban microcellular deployment scenario focuses on macro TRxPs with or without micro TRxPs and high user densities and traffic loads in city centres and dense urban areas. The key characteristics of this deployment scenario are high traffic loads, high user density, small coverage, and outdoor and outdoor-to-indoor coverage for mobile UEs, where UE is provided with continuous cellular connectivity using a lower frequency while being served with high traffic loads using frequencies above 52.6 GHz. Additionally, this deployment scenario can serve outdoor fixed wireless UEs or IABs with high traffic loads to mimic the last mile distribution networks. This scenario will be interference-limited, using macro TRxPs with or without micro TRxPs. A continuous cellular layout and the associated interference shall be assumed.
5.2.3  Urban micro
In the Urban micro deployment scenario, the sparse environment with no closely spaced high buildings are described, such as park areas, university campuses, stadiums, outdoor festivals, city squares or even rural areas, as transmitted with mostly LOS is mainly typical in the deployment scenario.
5.2.4  Urban macroWord-p. 62
The urban macro deployment scenario focuses on large cells for fixed wireless UE/IABs. The key characteristics of this scenario are supporting fixed nodes in urban areas. This scenario will be interference-limited, using macro TRxPs (i.e. radio access points above rooftop level).
5.2.5  Rural
The rural deployment scenario focuses on larger coverage for fixed wireless UE/IABs. Although the bands above 52.6GHz have higher propagation loss, relatively long coverage can still be achieved with line-of-sight transmission condition and high gain antenna. Therefore, Rural could also be a deployment scenario for the fixed wireless access and backhaul applications, which have LOS transmission conditions. The key characteristics of this scenario are wide area coverage supporting fixed nodes. This scenario will be noise-limited and/or interference-limited, using macro TRxPs.
5.2.6  Factory Hall
Similar to the indoor hotspot deployment scenario, factory hall deployment scenario focuses on medium coverage per site/TRxP and high user throughput and high user density inside the buildings. The key characteristics of this deployment scenario are high capacity, high user density and reliable communications.
5.2.7  Indoor D2DWord-p. 63
In this deployment scenario, usually the low cost device is involved, so the transmit power is lower and the antenna elements is much smaller compared with regular UE. The distance between the communicating devices is likely less than 5m and the typical device is pedestrian in this deployment. The system bandwidth varies depending on the particular services/application.
6  System Design RequirementsWord-p. 64
This section describe some of the system design considerations and requirements that are important for NR system operating in frequencies between 52.6 GHz and 114.25 GHz.
  1. Waveform
    • Power efficiency of power amplifier (PA): PA efficiency at higher frequency is expected to degrade and low PAPR waveforms designed to minimize PA backoff and maximize efficiency should be considered. At higher frequencies and especially in millimetre wave frequencies, output power per transistor as well as power added efficiency decrease. Waveform with high power back-off to support EVM and out-of-band emission requirements could dramatically reduce PA efficiency even further.
    • Dynamic range of ADC and DAC: The increase in PA back-off also affects the other device requirements, for example, the dynamic range of the ADC and DAC. A higher Tx DAC effective number of bits (ENOB) is required to accommodate higher PAPR, and extra oversampling in the baseband DSP, and Tx DAC may be needed to accommodate wider channel bandwidth. All of these are impacted by waveform, and therefore should be carefully evaluated.
    • Modulated signal accuracy and out-of-band emission: Power amplifier is designed and adjusted to meet RF requirements, such as spectral mask emission (SEM), adjacent channel leakage ratio (ACLR), in-band emission (IBE) and out-of-band emission (OBE) requirements, and error vector magnitude (EVM) requirements. Proper RF requirements are needed to determine appropriate in-band signal quality characteristics, minimize adjacent channel interference and impact to signals in adjacent channels. Occupied signal bandwidth and guardband for a given channel bandwidth in high carrier frequencies above 52.6 GHz require further investigation.
    • Complexity and performance of waveform: Given the high data rate and high sampling rates the system is expected to operate, the complexity and performance tradeoff for waveform generation/modulation and reception/demodulation should be considered.
    • Spectrum flexibility of waveform: Use cases and frequency allocations by various government bodies may require various bandwidth to be supported. Therefore, flexibility to support different system bandwidth should be considered in the design.
    • Robustness to frequency offset and phase noise: Carrier frequency offset and phase noise is much higher in spectrum beyond 52.6GHz because of imperfection of PA and crystal oscillator is more severe than that of lower bands. In addition, Doppler shift/spread is also larger with the carrier frequency increasing. As a result, robustness on frequency offset and phase noise is one of the key requirements for systems operating on bands above 52.6GHz. Increasing the subcarrier spacing for CP-OFDM waveform to better cope with increased phase noise could be investigated. For other potential waveforms impact from phase noise and ability to robustly handle phase noise should be investigated.
    • Feature re-usability and design commonality with existing NR specification: It would be good to be able to support features for FR1 and FR2 as defined in NR with minimal change (if possible) and support a common design structure that could support various use cases. To that extent further considerations of using an integer ratio between clock rates of NR below and NR above 52.6 GHz should be investigated. One possibility to achieve this would be to maintain the NR numerology scaling principle but extend to higher numerologies, i.e. Δf = 2μ × 15 kHz with an appropriate range of possible integer values for μ.
  2. MIMO
    • Multi-antenna technology with beamforming: Depending on deploying site and also applications, various antennas can be used in millimetre communication. Concerning implementation (e.g., cost, form factor), various type of antennas can be considered for developing NR above 52.6 GHz. There are four types of antennas can be considered in this frequency range: Parabolic, lens, waveguide array, and patch array.
    • Maximum supported layers: Up to two spatial layer could be supported using polarization diversity. Further study on maximum supported spatial layers taking into account support for even larger bandwidths and RF design challenges is needed.
    • Enhanced beam management: Larger antenna arrays is expected to support certain link budgets in high frequencies due to poorer free space pass loss, oxygen absorption, and the obstruction loss, even from people or foliage. This results in pencil-thin beams that require improvements in beam management robustness and overhead. Methods for managing narrower beams and greater number of beams should be studied. It should be noted depending on form factor and device, number of beams supported and beam codebook space could vary. Therefore, enhancement on discovery and tracking to support various beam assumptions should be investigated.
    • Enhanced path diversity: The narrow beams achieved with the larger arrays may result in a higher reliance on LOS paths. To improve coverage at these frequencies, methods for improving path diversity—increasing the probability of LOS paths—should be studied. Some examples may include collaborate MIMO techniques or same frequency multi-connectivity techniques.
    • Multi-cell/panel operation for high reliability and mobility: Considering propagation characteristics, it may be beneficial to support the near-LOS condition to UEs by position and angle tracking, and point-beamforming using massive antenna arrays.
  3. Power consumption
    • Compared to NR FR2, operation in the bands beyond 52.6 GHz may pose even more burden on UE power consumption due to potential large number of beams, low latency and high data rate transmission/reception (i.e., continuous processing of large code block, high order modulation, and security related processing [39]), and PA efficiency losses caused by RF components.
    • Power efficiency in baseband: Power consumption is one of the biggest problems in millimetre band communication. In addition to the process losses to the RF devices, the power dissipation in the ADCs is also very large. Widening the dynamic range required by the ADC when receiving high order modulation can consume high power. Therefore, power efficiency in both transmitter and receiver baseband should be considered for NR design above 52.6GHz. Improvement in uplink can be considered to reduce additional power consumption. For example, a low-power transmit scheme, advanced DTX, and a low-power beamforming scheme can be considered.
  4. Channelization and Bandwidth
    • Bandwidths for the system: Different regulatory bodies are already provide licensed band allocation with certain bandwidth. For example, 250MHz blocks that can be aggregated to up to 5 GHz in Europe, South Africa, and Canada, 4.75 GHz blocks in UK, up to 5 GHz and 0.9 GHz blocks in US. Additionally, 802.11ad/ay systems currently support multiple of 2.16 GHz block in unlicensed spectrum. NR system operating in above 52.6 GHz should consider the above bandwidths in the system design. Supported bandwidth should weigh in various considerations, including channelization, and hardware complexity. Wideband implementation has various implementation challenges, such as IF conversion, I/Q mismatch, increase of noise power, flatness of filter, and ADC, DAC performance.
    • Support of configurable bandwidth: NR beyond 52.6 GHz is anticipated to operate in different bands with different maximum possible bandwidths. NR beyond 52.6 GHz should therefore - as NR does - support configurable transmission bandwidths. NR should also support relatively narrow bandwidth smaller than the configured transmission bandwidth to improve RF and baseband power consumption and potentially to improve coverage with peak power efficiency. Additionally, support of narrow bandwidth that is smaller than the configured transmission bandwidth in the UL would help benefit transmission of HARQ feedback and small payload sizes.
    • Channelization: Supported bandwidths for the system should be considered during the channelization of NR above 52.6 GHz. The channel definitions may need to factor into account co-existence with other RAT, such as IEE 802.11ad/ay systems, and various uses cases, such as ITS, IAB, and V2X.
  5. Range, availability, and connectivity
    • Use cases for NR above 52.6 GHz can be divided into three classes, a class for outdoor mid / long-distance such as backhaul or relay, a class for short / mid-distance such as indoor or outdoor small cell, and a class for adjacent, near-field device or isolated area. Long distance classes, which include backhaul, can support up to 1 to 3 km range under LOS conditions and weather conditions. The inter-cell distance for outdoor small cells is assumed to be within a few hundred meters and the size of a floor or a room is assumed to be within tens of meters. Between devices or servers, less than 5 m range would be sufficient to minimize link interference.
    • Services provided by backhaul, the reliability of the wired network should be guaranteed. For indoor scenario, can guarantee higher availability as it is not effected by weather condition but it should consider the availability depending on the application services. For example, IIoT services may require URLLC-like (e.g. low BLER of 10-5) availability.
  6. Spectrum regime considerations
    • Frequency range above 52.6 GHz covers not only unlicensed spectrum but also licensed spectrum. Additionally, ECC/CEPT has set 63- 64 GHz as harmonized implementation of ITS. The licensed spectrum in the range is often dedicated to fixed links and could be used by IAB. So spectrum for 52.6 GHz would need to support systems that enable various target use cases spanning from unlicensed operation to V2X, IAB, and eMBB. Additionally, coexistence with 802.11ad and 802.11ay on the 60GHz unlicensed spectrum may need to be considered.
    • It would be preferred if similar system framework supports wide range of uses cases without significant specification effort or at the least the initial system framework support forward compatibility that allows extension to address various and different use cases.
  7. Other design considerations
    • Latency: For some uses cases and application services, the overall latency should be small enough to facilitate nominal operation of the application services. NR above 52.6GHz should support low latency operations.
    • Mobility support: For many use cases and deployment scenarios, low mobility is common assumption. Even for ITS/V2X use cases, low relative speed between the Tx and the Rx can be expected. Support for high mobility may not need to be prioritized as high layer mobility procedures could rely on low frequency bands with CA/DC operations.
    • Standalone and Non-standalone operations: Some use cases may not require standalone operation at bands beyond 52.6 GHz. For example, high data rate eMBB and mobile data offloading scenarios where wide area coverage is provided via another frequency band (e.g. lower band in FR1/FR2). Also some uses cases are suitable for standalone operations. For example, short-range high-data rate D2D communications and/or Industrial IoT. In scenarios that require standalone operations, initial access and related procedure should be studied including study on whether existing NR features and functionality are sufficient.
7  ConclusionWord-p. 67
A  Change historyWord-p. 68

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