1、 Extended Reality and 3GPP Evolution 1ContentsExecutive Summary.31.Introduction.42.Evolution of XR.53.XR Key Facilitators and Use Cases .63.1 XR Key Facilitators.63.2 VR Use Cases.73.3 AR Use Cases.84.XR Service Characteristics and Delivery Requirements.114.1 VR Wireless Requirements .114.2 AR Wirel

2、ess Requirements .134.3 MR and Beyond Wireless Requirements .135.XR Key Enablers.155.1 Split Computing/Rendering Architecture.155.2 Edge Computing.165.3 Spectrum Considerations.166.XR in 3GPP Standards .176.1 XR in Rel-15/Rel-16.176.2 XR in Rel-17.186.3 XR in Rel-18.226.4 XR in Rel-19.23Conclusion .

3、24Acronyms.25Acknowledgments.27Endnotes.28 Extended Reality and 3GPP Evolution 3Executive SummaryExtended Reality(XR)enhances our lived experiences with Augmented Reality(AR),Virtual Reality(VR)and Mixed Reality(MR).It creates either fully virtual,immersive environments or blends those virtual lands

4、capes and features with the“real”world.Its use cases are not limited to consumer applications like gaming,but also include enterprise,institutions,and manufacturing.XR will influence the way people play,work,learn,and interact with each another.VR,but particularly AR,requires significant development

5、 in multiple areas including but not limited to multi-media,artificial intelligence,computing,display systems,and communication to provide experiences that incorporate XR into our daily lives.Low latency,high reliability,lower power consumption and high capacity are key service requirements for the

6、success of XR.5G New Radio(NR)developed by 3rd Generation Partnership Project(3GPP)is designed to support emerging XR uses cases that require such Key Performance Indicators(KPI).While 5G NR benefits XR,potential enhancements for 5G and balanced KPIs require further end-to-end optimizations.This whi

7、te paper describes potential use cases with service delivery requirements.It also details how 5G can enable an end-to-end XR system,including how split computation architecture across various system components provides benefits for lower latency,higher reliability,higher rates,and less device comput

8、ation.Rel-15/Rel-16 offers a decent foundation for XR but has not been specifically designed or optimized for XR support.The paper examines the evolution of 5G systems from Rel-15 and 16 that can be leveraged for XR,before describing potential enhancements recognized by 3GPP in Rel-17 through Rel-18

9、 that are expected to optimize XR support including XR awareness,power optimizations,and capacity enhancements.The paper concludes by describing anticipated studies of localized mobile metaverse services in Rel-19.Extended Reality and 3GPP Evolution 41.IntroductionExtended Reality(XR)is an umbrella

10、term for Virtual Reality(VR),Augmented Reality(AR),and Mixed Reality(MR),as shown in Figure 1.XR will be the next-generation computing platform dictating our future relationship with the digital world by creating virtual experiences that are indistinguishable from reality.XR will majorly influence t

11、he way people play,work,learn,and connect.Figure 1:Different types of XR services1VR is a digital render designed to mimic visual and audio sensory stimuli of the real world as naturally as possible to an observer or user as they move within the limits defined by the application.With VR,a user usual

12、ly wears a head-mounted display(HMD)which completely replaces the users Field of View(FoV)with a simulated visual component.The VR user may also wear headphones for accompanying audio.In addition,head and motion tracking of the user in VR allows the simulated visual and audio components to be update

13、d to ensure that items and sound sources remain synced with the users movements.2VR is gathering momentum,but much research is still needed to enhance the users immersive experience.Advances include but are not limited to higher resolution,wider FoV,depth,haptic gloves,and audio propagation.With AR,

14、artificially generated visual and audio content are overlaid on the users current environment.Their observation of their current environment may be direct with no intermediate sensing,processing,rendering,or indirect,where their perception of their environment is relayed using sensors.With MR,virtua

15、l elements are inserted into the physical environment to provide the illusion that these elements exist in the real scene.VR,and especially AR,remains in its early stages and needs immense research,innovation,and development before they are implemented practically in daily lives.These technologies i

16、nclude optics,projectors,display systems,graphics,audio,hand tracking,eye tracking,face tracking,body tracking,world mapping and reconstruction,and Artificial Intelligence(AI).VR headsets provide visual input contained to the HMD,whereas AR glasses allow users to observe and use virtual objects over

17、layed in reality to annotate our world and interact with others.AR glasses and VR headsets operate within tight power and thermal budgets.AR glasses generally have small form factors and must operate within narrow budgets(lightweight,low power)to enable long sessions or all-day usage.Cloud gaming(CG

18、)is a closely related XR application that utilizes the edge server to render graphics on mobile devices.Game controller information is transmitted on the uplink,and the graphics rendered do not change on user movement and are generally with lower resolution compared to other XR systems.XR and CG3 ar

19、e currently one of the industrys most important 5G media applications under consideration.Extended Reality and 3GPP Evolution 52.Evolution of XRXR application enhancements need greater consideration as we move toward 6G.5G technology improved access to high-quality video,but 5G-Advanced will offer m

20、ore immersive user experiences,and 6G development is working to provide more holographic experiences.Digital twins,localization,and sensing are also being enhanced as these technologies move towards 6G.Factors like ecosystem support and strong communication between device and network manufacturers c

21、annot be overlooked.Communication and collaboration are necessary to enhance variables such as battery life,optics,power savings,and congestion control.Immersive media,3D mapping,sensing,and content development drive the development of XR which needs lower latency and higher bandwidths.The journey t

22、o 6G is steadily progressing.Between now and 2030,consumers will continue to see optical improvements,more vivid images,and enhanced VR headset features like tracking for hands,full body,and facial expressions(see Figures 2 and 3).Figure 2:XR is a long journey,consumer XR Devices Timeline4Figure 3:X

23、R evolution on the networks level Extended Reality and 3GPP Evolution 63.XR Key Facilitators and Use Cases XR services are complex and mandate many novel functionalities.While complex,XR services will transform the way we communicate,learn,and play.XR services will be the cornerstone of enterprise a

24、pplications,consumer applications,and everything in between.The metaverse and digital twins can successfully enable the deployment of future multi-sensory XR.3.1 XR Key FacilitatorsThe Metaverse blends physical and digital worlds into one where XR users,content,and digital entities interact.The meta

25、verse will bring XR to consumer homes,enterprise,and industrial realms.Users can see their physical actions reflected in the digital world and their virtual actions reflected in the physical world56.In essence,the metaverse can be a fictious world(e.g.,video game realm)that mimics day-to-day life in

26、 a virtual and digital domain(e.g.,a virtual replica of a power plant area).Figure 4:Metaverse landscapeThe metaverse could potentially usher in some form of blockchain technologies,crypto currencies or Non-Fungible Token(NFT)over a new iteration of the world wide web,i.e.,decentralized web.This cou

27、ld be a fundamental pillar enabling the world of distributed applications(dApps)as it reinvents how data moves through the overall network backbone.Essentially,it is an infrastructure layer that can transform the flexibility of dynamic data.This new modus-operandi presents challenges with operationa

28、l and energy efficiencies,but also provides new opportunities to make users a central part of this new internet and economy.Digital Twins:Digital twins constitute the fundamental link between the real world and the metaverse,and have been made possible largely by the Industrial Internet of Things(II

29、oT).Digital twins guarantee end-to-end digitization of complex physical assets,and consist of a physical and cyber twin.Tuneable,corresponding XR content for complex physical assets necessitates a digital twin.Artificial Intelligence(AI),Machine Learning(ML),and Autonomy:AI and ML have influenced al

30、most every industry by reshaping the limits of high-tech.Service and operational intelligence are necessary to guaranteeing the successful and efficient performance of XR services and for providing XR via wireless access.Service intelligence is used within the application itself like ML pertaining t

31、o rendering,actions related to the VR scene,and coordination of multiple holograms.Operational intelligence provides the network with intelligent mechanisms to perform optimization and self-sustainability in Extended Reality and 3GPP Evolution 7complex services like XR7.Ensuring end-to-end digitizat

32、ion of complex physical assets necessitates utilizing Internet of Things(IoT)devices and sensors.IoT devices with limited compute power are seeing developments that promise to unleash their true potential with edge compute capabilities that enable decision making,pre-emptive maintenance,and more.Ent

33、erprises can also benefit from smarter IoT ecosystems with advanced building management systems that encourage sustainability.Ultimately,successful deployment of the metaverse and digital twins guarantees successful emergence of XR services that are expected to penetrate versatile sectors and vertic

34、als,as shown in Table 1.Table 1:XR Use Case TypesUse Case Types Industry VerticalsCloud Gaming/SportsVirtual Events/CollaborationEducationPublic Safety/HealthcareAI/IOTConsumerXXXXPublic InstitutionsXXXEnterpriseXXManufacturingXFMCGXSimulationsX3.2 VR Use CasesVR was first renowned for the way it tr

35、ansforms screen-limited video games into fully immersive experiences.As a result,VR has catalysed significant evolution in the gaming industry leading to a paradigm shift in various industry verticals.3.2.1 Online Immersive GamingUsers can teleport from their living room to places like sporting stad

36、iums,fantasy realms,or simulated battlefields to experience seamless multi-player gaming experiences.Cloud-native applications and cloud gaming have opened the door for this new avenue of game engagement.While this concept is still developing,VR gaming will propel a novel gaming metaverse and online

37、 ecosystems.For instance,games like Roblox and Minecraft have 10 x in-app usage vs.Twitter and Facebook;its influence is undeniable8.3.2.2 Virtual Event ParticipationIt was not so long ago that the idea of instantly teleporting to another place seemed like science fiction.However,with the available

38、VR technology,maturity of the metaverse,and robust network,participating in highly immersive virtual events in near real-time is becoming a reality.Virtual events are vastly inclusive,encompassing a wide spectrum from concerts and fashion shows to team collaboration.Users can attend virtual concerts

39、 or host their own virtual events for customers,friends and family across states and countries,e.g.,a virtual open house.Enterprises also have opportunities to collaborate globally.For instance,a user could attend an immersive,virtual town hall meeting and after,“walk out”and order a pizza within th

40、e same virtual environment and pay with cryptocurrency.The user could consume the pizza virtually,but also once delivered to their physical location.Extended Reality and 3GPP Evolution 8Figure 5:Virtual open house use case3.2.3 Educational ExperiencesThe COVID-19 pandemic made it evident that educat

41、ional resources and mediums backbone should not be limited to classrooms and in-person settings.Education must be accessible remotely from anywhere,at anytime.Throughout the pandemic,many users were inhibited by connectivity constraints and the inability to solicit their physical senses to understan

42、d learning modules and seamlessly engage in classroom discussions.A VR classroom experience enables users to erase the boundaries between in-person and remote boundaries.The“360 camera”allows remote students to experience the classroom setting in a more immersive manner9.In addition,the virtual worl

43、d can usher in access to remote areas that go beyond online classes through virtual museum visits,virtual lab or company visits,and more hands-on approaches to learning.Research by Stanford University suggests that XR-enabled methods can lead to a 76%increase in learning efficiencies10.Access to cus

44、tomized study plans and learning material significantly benefits not only students,but also teachers.Figure 6:Mixed physical and virtual classes use caseWhile mission-critical services have a larger reach with AR services(described in Section 3.3.2),VR can further revolutionize public safety respons

45、e education through voice-driven training,and re-imagined,low-cost,remote Advanced Cardiac Life Support(ACLS)training for first responders.It also allows for early testing and calibration in simulated scenarios that can reduce the possibilities of error in actual emergencies.11 123.3 AR Use CasesVR

46、and AR share common denominators and use cases,but with varying methods of delivery.AR supplements our day-to-day life with virtual components rather than immersing the user in a virtual world.3.3.1 Mobile AR Video GamingLike immersive gaming experiences in VR,AR can leverage mobile phones,wearables

47、,and AR glasses to supplement AR content in our daily lives(e.g.,Pokmon Go).Ensuring the smooth flow of AR contents and their synchronization with the real world is ensured with the advancement of wireless networks that deliver reliable low latency while guaranteeing an extremely high rate.One facil

48、itating approach is the migration of cloudification of versatile interfaces and edge-enabled access13.Extended Reality and 3GPP Evolution 93.3.2 Mission Critical ServicesAR services are expected to exert major influence over multiple mission-critical services,from public safety applications to healt

49、hcare and industrial manufacturing.AR is a portal to a new avenue of tunability,engineering,and intervention.A medical doctor can perform remote surgery on teleported patients,and engineers can fine-tune machinery cyber-twins.The navy can execute missions with overlaid AR content.XR enables transcen

50、ding mission-critical tasks to be operated in the metaverse.That said,it is necessary to ensure that the goal of each service is attained within adequate safety measures.To do so,the end-to-end latency needs to be minimal to mitigate any risks and ensure a seamless execution of the task.Ultimately,t

51、his kind of feature promises access to healthcare from remote places without needing emergency transport.Figure 7:Remote healthcare3.3.3 Online ShoppingThe COVID-19 pandemic impacted many businesses and owners,leading to the closure of many shops,particularly small businesses.During that time,stores

52、 with online shopping venues faced less economic backlash,but the online shopping sphere still lacks some crucial features,like feeling the material,trying clothing on,and examining the size of the objects.AR can provide users with an immersive browsing experience in their favourite stores,and exami

53、ne the texture,size,and real color of their purchase from the comfort of their home.3.3.4 Spatial-Audio Multiparty Calls/ConferencesConference and multiparty calls have always lacked the human-centric component when relying solely on a screen,camera,and microphone.However,AR can remedy users device

54、limitations with holograms that solicit their senses to communicate and converse with each other.Here,the role of body language,gestures,and facial expressions will ensure a smoother human interaction that mimics real-time face-to-face experiences.Figure 8:Avatar virtual collaboration spaces Extende

55、d Reality and 3GPP Evolution 103.3.5 Digital Co-designCo-design systems are designed to aid in creating innovative products and incorporating them into a virtual-real environment.This process allows designers to focus on the practical design and its relationship with the external environment by inte

56、grating context awareness.Spatial computing may be emphasized by capturing data using spatial mapping and imaging technology.Capturing movement,emotions,and facial expressions are vital with co-design,so using new forms of man-machine interactions is just as vital to measurements of the human body.C

57、oupling the creativity of co-design with advanced user equipment and wearables will transform the next generation of Industrial IoT,because designers and practitioners require real-time shared platforms to work on projects simultaneously and make progress.Many enterprises,not limited to manufacturin

58、g,are experimenting with this concept.While the benefits of Co-design vary by project and vertical,early indications show substantial benefits.Extended Reality and 3GPP Evolution 114.XR Service Characteristics and Delivery Requirements5G services consists of three main thrusts:enhanced mobile broadb

59、and(eMBB),massive machine-type communications(mMTC),and ultra-reliable and low latency communications(URLLC).eMBB is designed to cater to the additional capacity needed to accommodate higher peak data rates for big crowds and mobile user equipment.Examples include high resolution multi-media service

60、s and 3D content.mMTC services are characterized by a massive number of sensors or connected devices,typically necessitating a considerably low volume of non-delay sensitive data(e.g.,smart grids,smart cities,etc.).URLLC services refer to services that are expected to have exceptionally low latency

61、and extreme high reliability.Such services are predominantly seen in mission-critical services like IoT devices used in surgeries or traffic safety.Figure 9:5G services thrustsXR traffic characteristics include quasi-periodic traffic in large chunks,irregular intervals and variable size,high data ra

62、te including uplink(UL)for ARservices,simultaneous transmission of 3Dvideo stream,and control data overthe same e2e connection.In addition,other key characteristics include low power consumption to extend battery life and minimize heat dissipation for user comfort,and tight delay and reliability con

63、straints to meet user Quality of Experience(QoE).XR services do not easily fall exclusively under any of the three main thrusts of 5G because they simultaneously necessitate the delivery requirements of eMBB and URLLC.The next sections delve into details of wireless delivery requirements of VR,AR,MR

64、,and beyond XR,delivery limitations of current 5G systems,and network aspects that require a major overhaul to fulfill the requirements of future XR services.5G-Advanced is set to evolve 5G Systems to its fullest capabilities from 3GPP Rel-18 onwards.The innovations from a large number of 3GPP 5G-Ad

65、vanced items will offer improvements to:daily experiences for people and machines,extensions for new services,and expansions to offer new functionalities.In addition,these technological innovations will provide operational excellence.Among others,it will continue to improve coverage and capacity,enh

66、ance end-user experience,and expand 5G capabilities beyond connectivity.144.1 VR Wireless Requirements VRs ultimate goal is metaverse immersion:a state of deep involvement,absorption or engagement.Simulating an experience of“actually being there”can be achieved if the network satisfies the applicati

67、on-level metrics such as display(or content)resolution,FoV angles,and application“lag”.Consequently,VR services must first immerse the user in a high-fidelity visual component.Guaranteeing the successful delivery of this visual component requires the wireless network to deliver extremely high data r

68、ates.Second,VR services must immerse the user in a multi-sensory experience predominantly through the haptic component.Guaranteeing the successful transmission of the haptic component requires taming the reliability and the latency of the end-to-end system.Here,it is important to note that for early

69、 generations of VR,a multi-sensory experience was not necessary.Additionally,the fidelity of the visual component was not as significant as in current and future XR generations.Wireless service requirements are therefore dependent on the current VR generation.Early deployments of VR only consisted o

70、f 360 videos or 360 videos with simple haptic feedback.This simple generation of VR services,categorized as“Advanced VR”15,requires a video resolution of full-view 12K video,and transmission data in the range of 796 Mb/s-11.94 Gb/s.The data rate range varies based on the compression technique perfor

71、med on VR content.A lossy compression would require a less stringent data rate but would lead to a generation loss.Meanwhile,lossless data compression is more efficient but would impede the wireless network with a more stringent data rate.Here,given that 5G downlink and uplink targets could possibly

72、 be more than 50 Mb/s almost everywhere,it will be hard to implement this on a large scale(wide area network)via a 5G network.The maximum downlink data rates can be Extended Reality and 3GPP Evolution 12up to 1 Gb/s,and one can roughly use 5G to satisfy advanced VR requirements.However,such VR exper

73、iences would not be multi-sensory and would suffer from a lossy data compression process.Here,such VR services would benefit from eMBBs high data rate capability.Figure 10:Quality of Service(QoS)requirements for VR phasesThe captured data curve inFigure 11depicts the rising data rate at the acquisit

74、ion side for various established and emerging video formats on a logarithmic scale.The human perceived data curve inFigure 11shows the amount of data for various video formats that is perceived by a viewer at a particular moment in time,taking into account the natural limitations of the human eye.16

75、Figure 11:Human perceived data rate while streaming video versus captured data rate.Current 5G systems fall short in supporting tactile intensive VR experience.In essence,multi-sensory VR services require high data rates,high reliability,and low latency simultaneously.Here,this experience mandates w

76、hat eMBB and URLLC can deliver simultaneously.Pertaining to the latency requirements,VR poses an instantaneous requirement on the wireless network compared to the traditional average latency KPI.17 This showcases that 5G falls short in delivering an“Ultimate VR”experience where data rates in the ran

77、ge of 6.37-95.5 Gb/s(the range varies based on the compression technique)need to be attained and a maximum end-to-end latency of 5 ms needs to be achieved.The end-to-end latency KPI stems from motion-to-photon(MTP)latency.In essence,reducing the motion-to-photon latency is a key metric for reducing

78、motion sickness when immersed in a VR experience.It is the delay between the action and reaction of a VR user depicted by the movement of the users head and the changes in the VR content observed.Another key metric regarding motion sickness that needs maintenance is jitter,or the difference in the l

79、atency perceived by the user over time.Extended Reality and 3GPP Evolution 13Enabling high data rates,high-reliability,and low latency simultaneously for VR can be achieved by resorting to versatile avenues,but the tradeoff between diversity and multiplexing is inevitable.For instance,the data rate

80、issue can be resolved by resorting to more abundant bandwidth at higher millimeter wave(mmWave)bands.The sub-THz range can indeed fulfill the rate needs,but such bands are highly susceptible to factors like blockage and molecular absorption,and lack robusticity for mobility,significant communication

81、 range,and beam misalignment.Relying on ultra-massive multiple-input-multiple-output(MIMO)base stations can enhance data rates,and Reconfigurable Intelligent Surfaces(RIS)can improve the reliability of line-of-sight(LoS)links.However,such bands and techniques are inherently unreliable and cannot gua

82、rantee consistent dependability.Tiling scheme-based streaming strategies exist for the generations older than entry-level VR that limit the size of transmitted content and reduce data rates and delay requirements imposed on the wireless network.Such tiling schemes implement a useful trade-off betwee

83、n bandwidth consumption and coding efficiency and can be utilized in settings where bandwidth is limited to more evolved VR generations.However,such tiling-based streaming strategies limit the 360 quality of VR video perceived.While such streaming schemes are useful,they are limited in their applica

84、bility to more evolved VR generations.AI and ML mechanisms that can enable enhanced real-time network optimization must be considered to tame high reliability an achieve low end-to-end latency.18 Processes occurring at multiple layers,ranging from beam-tracking to resource block allocation and VR fi

85、eld-of-view optimization,need to be governed by low-latency aware AI mechanisms.Nonetheless,current ML and AI mechanisms face multiple challenges with delivering stringent wireless requirements.Their predictive capability provides the network with more awareness and robustness towards processes occu

86、rring at various layers;however,their performance relies on large datasets and requires lengthy training times or exploration periods.Evidently,this nascent,open problem is fundamentally important to guarantee a robust network performance when delivering XR services.VR services predominantly occur i

87、n indoor areas,and this key advantage can benefit from fixed wireless access using higher frequency bands.Here,the reliability and low latency of the overall performance can be better controlled in an indoor environment.4.2 AR Wireless Requirements ARs goal seeks to overlay the users reality with vi

88、rtual components that are up and running in the metaverse,or with cyber twins of a physically complex asset in real-time.Like VR,AR mandates a high data rate,reliability,and low latency simultaneously when granted in a multi-sensory setting.AR requires less immersion for a supplementation of objects

89、 in users daily lives compared to full immersion into the metaverse,so rate requirements can be slightly lower than VR.AR mainly depends on the users interaction with the AR components in real time,so such components must actively update and accompany the correct spatial-temporal constraints of the

90、users daily life.In addition to minimizing the end-to-end latency,outdated information in an AR network can potentially lead to tremendous risks when deployed in mission-critical services.The freshness of information can be quantified by the concept of Age of Information(AoI).19 AoI depends on gener

91、ating and transmitting AR content while capturing the freshness of receiver information.Given that AR depends on the users input more than VR,AR necessitates a high-rate bidirectional(downlink and uplink).Therefore,it is important to propose novel,AI-oriented network optimization frameworks that can

92、 guarantee a wireless AR service with high-rate,reliable,and low-latency bidirectional links.4.3 MR and Beyond Wireless Requirements The concept of MR is not concretely defined by academia or industry.Nevertheless,MRs main objective is to combine the capabilities of AR and VR in the same device.MR u

93、ses Figure 12:Example of view-port dependent virtual reality streaming Extended Reality and 3GPP Evolution 14pose information with up to six degrees of freedom(6DoF)20(position x,y,z,and rotation yaw,pitch,roll)to minimize data rates by only sending the visible field of view,known as“view-port depen

94、dent VR streaming”.MR is evolving alongside 3D imaging technology to create the highly coveted holographic teleportation application domain.Holographic teleportation is the evolution of ultimate extended reality,whereby the user needs to solicit their senses.In addition to stringent XR wireless requ

95、irements,holographic teleportation requires massive data rates in the range of 5 Tbps.19 Immersing the user in the metaverse requires tight synchronization between the holographic flows when considering user sense solicitation.Therefore,the risk of putting the user in a motion-sickness state grows s

96、ubstantially as the requirements for delivering this service are more stringent than in previous XR generations.On top of connectivity requirements,different types of sensing modalities are necessary to deploy multi-sensory XR over wireless networks.Effectively,high-precision and high-resolution tra

97、cking feedback are necessary to provide information about the 6DoF of each users head and body with a cognizant situational awareness of the XR users surroundings.Empowering a wireless network with such capabilities can also be done by leveraging higher frequency bands(similarly to the high data rat

98、e requirement).19 These bands can provide a high-resolution sensing capability with their large bandwidth if properly deployed.Fully multi-sensory XR and holographic teleportation has not been realized yet and requires a lot of technological advancements on the device,network,and technology level.Ex

99、tended Reality and 3GPP Evolution 155.XR Key Enablers5.1 Split Computing/Rendering ArchitectureWhile the long-term vision to the metaverse is 5G powered AR glasses(Figure 13.1)that connect directly to the cloud,a near-time solution are Wi-Fi-powered AR glasses that communicate to the cloud via a 5G

100、enabled phone or laptop(Figure 13.2).In the future,a 5G AR glass may utilize either 5G or Wi-Fi as available(Figure 13.3),and a seamless experience between Radio Access Technologies(RATs)is preferred for the best user experience.One option to realize low power consumption modem is through the Releas

101、e 17 Reduced Capability(RedCap)features by limiting the bandwidth to 20MHz and the number of antennas to two,again,as an option.Figure 13.1:Direct ConnectFigure 13.2:Phone-to-GlassFigure 13.3:5G AR glass utilizing 5G or Wi-FiIn the Edge-to-Phone-to-Glass AR system of Figure 13.2,the glasses communic

102、ate with the phone over Wi-Fi,and the phone communicates with the server over 5G.In split XR architecture the users pose and video information flow from the glasses to the phone to the server.The server processes the data and sends the encoded graphics back via the phone to be displayed onto the gla

103、sses.The split XR system leverages computing power from the edge compute server for graphics rendering.The Round-Trip Time(RTT)for this entire process is called Motion to Render to Photon latency(M2R2P),as illustrated in Figure 14.The Wi-Fi and 5G RTT are key components of this M2R2P.This 5G round-t

104、rip includes the time required to transport a complete video frame and the pose information between the server to the device along with scheduling,queuing delay,and propagation delay in core networks.Different XR devices may differ in tethering between the device carrying the 5G Uu modem and the XR

105、device,the placement of the 5G Uu modem,the XR engine and localization support,the power supply,and the typical maximum available power.Sensors are placed on all device types.The XR engine can be broadly divided into:21 External:The device only supports display.Any scene recognition,if applicable,is

106、 not on the device.Split:The device performs viewport pre-rendering and post-rendering.With split rendering,the computation between the server and the device may deliver truly immersive and enhanced experiences.Varying types of architectural splits differ by the functional split of main tasks betwee

107、n the XR servers and XR devices.With split compute/rendering,network functions run an XR engine to support processing and pre-rendering of immersive scenes,and the delivery is split into more than one connection,e.g.,Split rendering,Edge Computing,etc.The latency and interaction requirements depend

108、on the use case and the architecture implementation.XR device:A device that does full rendering of the viewport in the device.Figure 14:Split XR architecture with M2R2P latency=5G RTT+Device processing+Server Processing Extended Reality and 3GPP Evolution 165.2 Edge Computing5G NR multi-access edge

109、computing(MEC)brings applications,storage,switching,and control functions closer to the location where they are needed,which improves data processing and reduces latency.Moving on-device processing to the cloud allows for faster response times and lower battery usage,potentially transforming industr

110、ies such as manufacturing,transportation,entertainment,and more.With edge computing,User Equipment(UE)can access services hosted close to the serving Base Station(BS).Lower latencies can improve end-user experience,while reduced backhaul transport requirements can improve network efficiency.Hosting

111、services close to the serving BS means that there is User Plane Function(UPF)and DN(Data Network)of Local Area Data Network(LADN)at a location which is geographically close to the serving BS.The UPF and the DN/LADN could be co-located with the base station,or they could be co-located with a router w

112、ithin the transport network.Figure 15:Cloud and edge processing22The role of edge computing as a network architecture is an important consideration for enablement of XR and CG.For example,a museum could use AR to provide visitors with additional information as they tour the venue.The edge computing

113、application could run on a local server which recognizes and tracks the visitors location and provides relevant location information.As such,edge computing may provide several benefits,such as lower latency,higher bandwidth,and reduced backhaul traffic.The SA6 Study on application architecture enabl

114、ing Edge Applications23 defines the necessary modifications to 5G System architecture to enhance edge computing.XR edge applications are expected to take advantage of the low latencies enabled by 5G and the Edge network architecture to reduce the end-to-end Application-level latencies.In addition,3G

115、PP TR 23.758 and 3GPP TS 23.558 identify a new set of application layer interfaces for edge computing that are potentially useful for the integration of edge computing.Specifically,the interfaces will enable application-layer discovery of Edge Application Servers,capability exposure towards the Edge

116、 Application Server,and procedures for onboarding,registration,and lifecycle management of Edge Applications.5.3 Spectrum ConsiderationsA good XR user experience requires high data rates,high-reliability,and low/ultra-low latency simultaneously.Although reliable and ideal for mobility,FR1 has capaci

117、ty restrictions due to limited bandwidth.The mmWave and sub-THz bands can fulfill data rates and latency requirements but have limited range and mobility.Overcoming the spectrum challenges utilizing AI and ML technology to bring in high reliability and data rates will be crucial to the overall consu

118、mer experience 24.Figure 16:Showcasing spectrum capacity vs.coverage considerations Extended Reality and 3GPP Evolution 176.XR in 3GPP Standards XR is a service between URLLC and eMBB requiring a balance among KPIs which include high reliability,low latency,low power consumption and high capacity.3G

119、PP introduced 5G NR in Rel-15,which is mainly for eMBB with some support for URLLC.XR can leverage 5G NR as a basis with further XR specific enhancements.The following sections outline XR in 3GPP releases.6.1 XR in Rel-15/Rel-16Rel-15/Rel-16 introduced features for URLLC and power savings that provi

120、de higher reliability,lower latency,and larger power savings,but these features have not been specifically designed and optimized for XR.For example,these features do not account for XRs periodic traffic that comes in larger burst sizes.Moreover,some features may trade reliability and latency for th

121、roughput.Consequently,this decreases network capacity and the number of XR users that can be reliably served.Rel-17 XR Study Item(SI)and current Rel-18 targets XR-specific enhancements,but some Rel-15 and Rel-16 features that support low latency and/or power savings could be baseline features for XR

122、.Rel-15 enhancements such as mini-slot transmissions,downlink preemption,grant-free transmissions,and frontloaded DMRS(Demodulation Reference Signals)enable low latency and are useful for XR applications.At the physical layer,enhancements for providing higher reliability and lower latency included t

123、he support of new Downlink Control Information(DCI)formats:DCI format 0_2,DCI format 1_2,and DCI format 2_4.Additionally,the legacy DCI formats include new fields.Priority Indicator is a one-bit indicator that signals High Priority or Low Priority to facilitate the intra-UE prioritization to resolve

124、 traffic conflicts.XR applications can potentially benefit from these features given the tight latency requirement and the need to prioritize low latency XR traffic to meet delay budgets.With dynamic power boosting introduced in Rel-16,a UE with enhanced power control may be boosted over eMBB,i.e.,t

125、ransmitting a low latency traffic transmission power.Rel-16 also introduced uplink cancellation that allows a UE to get uplink resources for latency-sensitive services which may be previously assigned to another UE.All these features benefit XR services requiring low latency.XR devices have a small

126、form factor and may benefit from lower power consumption to save battery life.Rel-16 introduced enhancements to save UE power that may be considered baseline schemes for XR devices.The key features include a Physical Downlink Control Channel(PDCCH)wakeup signal(PDCCH-WUS),which indicates to the UE w

127、hether PDCCH is to be transmitted in the Connected Mode Discontinuous Reception(CDRX)OnDuration.If no indication is present,the UE can continue to sleep through CDRX OnDuration and save battery power.Some features that are useful for XR scheduling could be the use of uplink configured grant(ULCG)for

128、 the UL XR video data transmission.When compared to a dynamic grant(DG),ULCG reduces the overhead of a scheduling DCI.Moreover,the UE does not need to transmit Scheduling Request(SR),monitor PDCCH for UL grant,transmit a Buffer Status Report(BSR)and then finally transmit UL data.This reduces latency

129、 and allows UL packet transmission to meet the PDB.However,the configuration of resource allocation of ULCG is semi-static,and enhancements might need to be adapted to the variable packet size.The UE may use the UE Assistance Information(UAI)to indicate its preferred power savings parameters,such as

130、 providing preference on the parameters of the CDRX configuration.This allows a UE to adapt to different applications and bandwidth,thus saving more power.Furthermore,the maximum number of multiple input multiple output(MIMO)layers,maximum aggregate bandwidth,and the maximum number of component carr

131、iers may also be adapted based on UAI.Specific work for XR was initiated in Rel-1625,where the SA4 Work Group(WG)introduced XR by providing definitions,core technology enablers,and a summary of device form factors.It further identified the relevant client and network architectures,application progra

132、mming interface(API)s,and media processing functions that support XR use cases.In addition,the media formats,including audio and video,accessibility features,and interfaces between client and network are required to offer such an experience were identified.Also considered were key performance indica

133、tors and QoE metrics for relevant XR services.While XR services can build on 5G NR,there are key issues that have been recognized in 3GPP as part of the“Study on XR enhancements for NR”in Rel-17,and the 5G system is expected to evolve to address the issue through Rel-18 and beyond.The next sections

134、provide a system level overview of the 5G evolution to better support XR.Extended Reality and 3GPP Evolution 186.2 XR in Rel-17This section provides an overview of the XR Study in Rel-17,“Study on XR enhancements for NR”.Table 2 summarizes relevant 3GPP Rel-17 efforts in the context of XR.The Rel-17

135、 SI in RAN1 was coordinated with SA4,and the adopted statistical traffic model for CG/AR/VR traffic for downlink and uplink is shown in Table 3 and Table 4.The video frame size is assumed to be generated from Truncated Gaussian Distribution with standard deviation,min,max of 10.5%,50%,150%of mean da

136、ta rate.Jitter for frame arrivals into 5G systems is also assumed to be Truncated Gaussian with standard deviation,min,max of 2,-4,4 msec.On the uplink,all XR services contain the uplink flow that carries frequent small control packets such as from UL pose/control of the HMD.The delay bound for this

137、 type of flow is small(10 msec).The SI considered the evaluation methodology for capacity,power,coverage,and mobility.Performance evaluations were presented,as such,for these aspects.The study resulted in the Technical Report(TR)38.838.The SI TR 38.838 includes the potential enhancements with the ev

138、aluation results for increasing XR capacity and decreasing power consumption.The evaluations were based on multi-cell system level simulation.The evaluation methodology includes the XR traffic model,deployment scenarios,UE configurations,BS configurations,TDD UL-DL slot format pattern,etc.In additio

139、n,it was agreed that UE power and capacity are jointly evaluated to avoid adopting any power enhancement that can cause a decrease.The most major issues and design challenges for XR are discussed in the following sections.Power Savings Enhancement:The power study aims to understand the NR UE power c

140、onsumption performance for XR applications,and identify any issues and performance gaps which could be useful for understanding the limitation of current NR systems in supporting XR applications,and the potential directions for necessary future enhancements to improve power efficiency.The main power

141、 savings issues are:Mismatch between the CDRX cycle and XR traffic periodicity:A tempo mismatch exists between the Rel-15 and Rel-16 CDRX cycle values and the XR DL frame arrival periodicity.The typical XR DL frame rates are 60,120 frames per seconds(fps),of which frame periodicities are 16.67ms,8.3

142、3ms while the configurable Rel-15/Rel-16 CDRX long cycle values are 10,20,32,40ms,etc.and short cycle values are 2,3,5,6,7,8,10,14,16,20,30,32,35ms,etc.Since CDRX cycle values support only integer multiples of 1ms,no matter which cycle periodicity is chosen from currently available values from 38.33

143、1,it cannot be exactly aligned with DL frame arrival timing.The following figure illustrates the mismatch between 60fps and CDRX cycles of 16ms and 17ms.This mismatch would lead to XR capacity loss due to larger latency and/or larger UE power consumption to keep the same latency performance.Figure 1

144、7:Mismatch between XR DL traffic(60fps)and R15/16 CDRX periodicityWGSI/WI TRSA1XR(and Cloud Gaming)use cases are outlined in SA1 study item on Network Controlled Interactive Services(TR 22.842)SA2Work item on 5G System Enhancement for Advanced Interactive Services(SP-190564)proposes to introduce new

145、 5Q1s to identify the requirements on traffic from SA1 NCISSA4Feability Study on Traffic Models and Quality Evaluation Method for Media and XR Services in 5G Systems(TR 26.926)SA6Edge Computing is a network architecture to enable XR and Cloud Gaming and is under study in the SA6 Study on application

146、 architecture for enabling Edge Application(TR 23.758)RAN1Study on XR Enhancements for NR(TR 38.838)Table 2:XR Rel-17 Study Items and Work Items Extended Reality and 3GPP Evolution 19Table 3:Traffic models and QoS constraints used to evaluate XR applications in DL directionTable 4:Traffic models and

147、 QoS constraints used to evaluate XR applications in UL directionApplicationCGVRARTraffic modelVideo single-streamVideo single-streamVideo single-streamBitrate30 Mbps30 Mbps30 MbpsPacket rate60 fps60 fps60 fpsPacket Delay Budget(PDB)15 ms10 ms10 msPacket Error Rate(PER)1%1%1%Number of streams111Para

148、metersVR/AR/CG(UL pose or controller)AR(scene+video)Audio+Data(all use cases)Periodicity (ms)41/60*1000 (=60fps)10Success%99 (90,95 optional)9999Packet size(bytes)100Derived from data rate&distributionDerived from data rate&distributionDelay Bound(ms)1030 (10,15,60 optional)30Data rate (Mbps)Derived

149、 from packet size&periodicity10(20 optional)1 Extended Reality and 3GPP Evolution 20Handling the mismatch is currently being discussed in Rel-18.Possible solutions may include allowing multiple CDRX configurations,non-integer periodicity,configuring cycle pattern,and dynamic indication for adjusting

150、 the start offset.Mismatch between the PDCCH monitoring periodicity and XR traffic periodicity:Similar to the CDRX issue above,the misalignment in time causes capacity loss or consumes additional power due to frequent PDCCH monitoring.Jitter handling:The XR DL traffic arrival has jitter,which makes

151、exact frame arrival timing random even after the tempo mismatch problem is solved.For example,if the DL burst arrives later than the expected time of arrival(where potentially CDRX On duration start is configured),as shown in Figure 18,the UE should wait for the DL burst arrival while performing unn

152、ecessary PDCCH monitoring.This unnecessary PDCCH monitoring increases UE power consumption.The variable XR frame size also results in high power consumption since the configuration is inefficient and usually based on the maximum packet size.Capacity Savings Enhancements:Similar to power savings enha

153、ncements,the purpose of the capacity study is to understand the performance of NR systems for XR applications and identify any issues and performance gaps that limit the current NR systems in supporting XR applications.In addition,such a study provides potential directions for necessary future enhan

154、cements to better support XR.Enhancement to semi-persistent scheduling:As the traffic generated by the XR application is quasi-periodic,it is suitable to use ULCG for the UL XR video data transmission.Compared to dynamic grant(DG),ULCG reduces the overhead of a scheduling DCI.Moreover,the UE does no

155、t need to transmit SR,monitor PDCCH for UL grant,transmit a BSR and then finally transmit UL data.This reduces latency and allows UL packet transmission to meet the PDB.The configuration of resource allocation of CG is semi-static.Therefore,the ULCG configuration cannot adapt to the XR traffic packe

156、t sizes.Moreover,A tempo mismatch exists between the Rel-16/Rel-17 Semi-Persistent Scheduling(SPS)/ULCG cycle values and the XR UL/DL frame arrival periodicity.The typical XR traffic periodicities are 60,120 frames per second(fps)or Hz;frame periodicities are 16.67ms and 8.33ms.Since ULCG/SPS period

157、icity values support only integer multiples of slot,no matter which periodicity is chosen from currently available values from TS 38.331,it cannot be exactly aligned with UL/DL traffic arrival timing.Figure 19 illustrates the XR periodicity mismatch between 60fps XR traffic and ULCG/SPS periodicity

158、of 16 slots and 17 slots in 15kHz SCS.This would lead to XR capacity loss due to the packet delay caused by the timing difference between ULCG/SPS resources and actual XR traffic.Current discussions in Rel-18 include considerations for SPS/ULCG enhancements using either semi-static or dynamic approa

159、ches.Figure 19:Mismatch between XR UL/DL traffic(60fps)and Rel-16/Rel-17 ULCG/SPS periodicity(16 slots or 17 slots)Figure 18:Late DL packet(burst)arrival with positive jitter with respect to the expected arrival time Extended Reality and 3GPP Evolution 21Other enhancements useful for XR capacity inc

160、lude(and are not limited to):delay-aware scheduling,enhancements to multi-PDSCH/PUSCHs scheduling using single DCI,WUS,Hybrid Automatic Repeat Request(HARQ-ACK)enhancements,and enhancements to measurement gaps.Moreover,given the large transport block sizes and the PDB that allows for a couple of HAR

161、Q retransmissions,Code Block Group(CBG)-based HARQ can be beneficial for XR use cases as current link adaptation mechanisms and the corresponding UE CQI feedback designs are suboptimal for CBG-based transmissions.XR Awareness at RAN:The latency and reliability QoS parameters in 5G systems are specif

162、ied for traffic in terms of“packets”(e.g.,PDB,PER).On the downlink,the packets correspond to the packet data unit on the N6 interface inbound towards the UPF.These packet data units are typically(Internet Protocol)IP packets,so the packets correspond to the IP payload.XR(and CG)application traffic,h

163、owever,on the downlink typically consists of encoded video or scene information.Typically,the applications require a certain minimum granularity of application data to be available on the client side before the next level of processing can start.For example,in certain configurations,application clie

164、nt processing can start only if all bits or a certain percentage of bits of a video frame are available.Although this information is packetized into IP payloads,the minimum granularity of traffic consumption on the application client side will require a certain minimum set of IP packets available be

165、fore the next level of processing can start.We refer to this minimum granularity of information that a given application requires as a Packet Data Unit Set“PDU Set”.XR(and CG)traffic consists of bursts of traffic that can carry one or more PDU Sets,where the PDU set is composed of one or more PDUs c

166、arrying the payload of one unit of information generated at the application level(e.g.,a frame or video slice)26.The QoS parameters specified in packets do not adequately capture the application requirements,typically in terms of PDU Sets.First,applications can have a certain PDU Set error rate PS-E

167、R requirement,where PS-ER is the percentage of PDU Sets in error in a specified measurement window.Specifying the PER does not adequately specify the PS-ER.If multiple IP packets in a PDU Set are in error,then the system can operate at a point where PER is met,but PS-ER is not satisfied.Therefore,it

168、 is observed that specifying PS-ER to the 5G system as a QoS parameter can be beneficial.Second,applications can have a certain delay requirement on a PDU Set that cannot be adequately translated into packet delay budget requirements.For example,if the PDU Set delay budget(PSDB)is 10ms,then PDB can

169、be set to 10ms only if all packets of the PDU Set arrive at the 5G system simultaneously.If the packets are spread out,then PDU Set delay budget is measured either in terms of the arrival of the first packet of the PDU Set or the last packet of the PDU Set.In either case,a given PSDB will result in

170、different PDB requirements on different packets of the PDU Set.It is observed that specifying the PSDB to the 5G system can be beneficial.As such,signalling new 5G QoS Identifier(5QI)attributes(delay budget,error rates,etc.)based on the PDU Set on the control plane is useful.On the user plane,the ap

171、plication server may mark the IP packets to differentiate packets which belong to the same set and/or bursts.Third,not all bits within a PDU Set are equally significant.Extended Reality and 3GPP Evolution 22For example,if the application implements an application-level error correction,then the appl

172、ication client only consumes a certain fraction of the bits of a PDU Set,and the remaining bits need not be transmitted to improve capacity.If an application implements error concealment techniques,it can tolerate a certain percentage of bits of a PDU Set in error.Certain video encoder configuration

173、s can consume all bits of a PDU Set up to the first bit in error.All subsequent bits after the first bit in error can be discarded since the corresponding decoder cannot consume it.The treatment of bits within a PDU Set can be specified via a QoS parameter called PDU Set content policy.Specifying th

174、is content policy to the 5G system as a QoS parameter can be beneficial.In addition to PDU set awareness,the 5G system can benefit from an awareness of the bursts that can constitute multiple PDU Sets.For example,if the 5G system is aware of the end of the burst,then it can ensure that UE can be sen

175、t to sleep without having to implement inactivity timers,resulting in additional power savings.Other useful attributes that may be useful to the 5G system and currently being discussed as part of the Rel-18 SI may include(and may not be limited to):PDU set periodicity,priority,size,or number of PDUs

176、 in a PDU set,jitter characteristics,etc.6.3 XR in Rel-185G-Advanced standardization is currently in the early stage,with Release 18 work started in RAN in Spring 202227 and further evolving28 in 3GPP Rel-19 and Rel-20.The 3GPP related XR SI and Work Items(WI)in Rel-18 are summarized in Table 5.Tabl

177、e 5:XR Rel-17 SI/WIsWGSI/WI TRSA2Study on architecture enhancement for XR and media services(SP-211646)RAN1/RAN2Study on XR enhancements for NR(RP-213587)In December 2021,a new Study Item,“Study on XR Enhancements for NR,”was approved 29.The agreed timeline discussed in RAN1#109-e is shown in Figure

178、 20.From the RAN perspective,the two important milestones are the provision of the TR for information at RAN#97 in September 2022 and the provision of the TR for approval at RAN#98 in December 2022.The task is for RAN1 and RAN2 to complete the work in November 2022.The study in Rel-18 is to be based

179、 on Rel-17 TR 38.838,on corresponding Rel-17 work from SA430,and on Rel-18 work from SA231.The objectives are summarized into XR-awareness,XR-specific Power Saving,and XR-specific capacity improvements32.The main enhancements include the ones described in Section 5.2.Figure 20:XR TU across working g

180、roups for Rel-1833 Extended Reality and 3GPP Evolution 236.4 XR in Rel-19To support the XR KPIs requirements,prediction of,or fast adaptation to,RF conditions changes is critical.This is especially true in mmWave and higher frequencies systems which experience higher propagation losses and are more

181、susceptible to blockage.These channel conditions are exacerbated by use cases that require high speed of rotation and motion.Perception assisted beam selection is useful for such scenarios/use cases.SA1 approved a study on Localized Mobile Metaverse Services in Study Item Description(SID)34.These me

182、taverse services would involve coordinating input perception/sensing data from different user devices(such as sensors and cameras)and coordinating output data to different devices at different destinations to support the same application.This study will investigate specific use cases and service req

183、uirements for 5GS support of enhanced XR-based services.XR-based services are an essential part of“Metaverse”services considered in this study,and potentially other functionality to offer shared and interactive user experience of local content and services,accessed either by users in the proximity o

184、r remotely.In particular,the following areas will be studied:Support of interactive XR media shared among multiple users in a single location,including:Performance aspects;e.g.,latency,throughput,connection density Efficiency and scalability aspects for large numbers of users in a single location.Id

185、entification of users and other digital representations of entities interacting within the metaverse service.Acquisition,use,and exposure of local(physical and digital)information to enable metaverse services,including:Acquiring local spatial/environmental information and user/UE(s)information(inclu

186、ding viewing angle,position,and direction);Exposing local acquired spatial,environmental,and user/UE information to 3rd parties to enable metaverse services.Extended Reality and 3GPP Evolution 24Conclusion Extended Reality(XR)will be the next-generation computing platform to determine our relationsh

187、ip with the digital world today and in the coming years.XR will influence how people play,work,and connect.XR will impact all aspects of consumer life,industrial and manufacturing verticals,education,emergency response,and healthcare.Digital Twins,AI/ML,IoT,are integral to the evolution and implemen

188、tation of XR.Digital twins link reality and the metaverse by guaranteeing end-to-end digitization of complex physical assets.Artificial Intelligence and Machine Learning connect almost every industry with XR services,and provide the necessary service via wireless access.Furthermore,using IoT devices

189、 and sensors with edge computing capabilities will enable pre-emptive decision-making maintenance.Verticals can benefit from a smarter ecosystem of IoTs while encouraging sustainability.Verticals include,but are not limited to,Enterprise,Public Safety,NFTs,Consumers Verticals,and Manufacturing.VR is

190、 renowned for its capacity to transform screen-limited video games into fully immersive experiences.Even though AR and VR share common virtual components in our daily lives,AR supplements our day-to-day life with virtual components rather than immersing the user in a virtual world.XR service charact

191、eristics and delivery requirements incorporate 5G services like eMBB,mMTC,and URLLC.5G NR MEC brings applications,storage,switching,and control functions closer to where they are needed,improving data processing,and reducing latency.Increased efficiency allows for faster response times and lower bat

192、tery usage,potentially transforming industries such as manufacturing,transportation,entertainment,and more.Certain aspects of edge computing help improve the end-user experience and network efficiency.The paper also discusses the role of split rendering/architecture for the phone to glass topology.3

193、GPP is considering various enhancements for the support of XR including enhancements for power savings,capacity and XR awareness in Rel-17 and Rel-18.Finally,the paper discusses some future directions 3GPP is targeting XR-specific enhancements in Rel-19.Aside from advancements in technologies not li

194、mited to optics,projectors,display systems,graphics,audio,tracking and AI;from communications perspective,the standards enhancements and design aspects that are discussed and recommended in this paper together with the split rendering/computation architecture make it more likely to realize the promi

195、sed benefits of XR,for example,low power,low latency high reliability with a small form factor device that provides XR services in a wide area.In the future,advances in beam perception,machine learning and artificial intelligence can further bring benefits and make the XR dream a reality.3GPP and th

196、e growing 5G mobile wireless industry ecosystem are entering a new era of 5G innovation and should continue to collaborate to focus on the key areas as described in this white paper to progress XR to reach its full potential as it affects the way we live,play and work.Extended Reality and 3GPP Evolu

197、tion 25Acronyms5QI:5G QoS Identifier6DOF:Six Degrees of FreedomACLS:Advanced Cardiac Life SupportAI:Artificial IntelligenceAPI:Application Programming InterfaceAR:Augmented RealityBS:Base StationBSR:Buffer Status ReportCBG:Code Block GroupCDRX:Connected Mode Discontinuous ReceptionCG:Cloud gamingDCI

198、:Downlink Control InformationDL:DownlinkDMRS:Demodulation Reference SignalsDN:Data NetworkFoV:Field of ViewHARQ:Hybrid Automatic Repeat RequestHMD:Head-mounted displayIIoT:Industrial Internet of ThingsIoT:Internet of ThingsIP:Internet ProtocolKPI:Key Performance IndicatorLADN:Local Area Data Network

199、LoS:Line-of-sightM2R2P:Motion to Render to PhotonMEC:Multi-access edge computingMIMO:Multiple-input-multiple-outputML:Machine LearningmmWave:Millimeter wave MR:Mixed RealityMTP:Motion-to-PhotonNFT:Non-Fungible Token Extended Reality and 3GPP Evolution 26NR:New RadioPDB:Packet Delay BudgetPDCCH:Physi

200、cal Downlink Control ChannelPDU:Packet Data UnitPER:Packet Error RatePSDB:PDU Set delay budgetPUSCH:Physical Uplink Shared ChannelQoE:Quality of ExperienceQoS:Quality of ServiceRAN:Radio Access NetworkRAT:Radio Access TechnologiesRel:ReleaseRIS:Reconfigurable Intelligent SurfacesRTT:Round-Trip TimeS

201、A:System ArchitectureSCS:Sub-Carrier SpacingSI:Study ItemSID:Study Item DescriptionSPS:Semi-Persistent SchedulingSR:Scheduling RequestTR:Technical ReportUAI:UE Assistance InformationUE:User EquipmentUL:UplinkULCG:Uplink configured grantUPF:User Plane FunctionURLLC:Ultra-reliable and low latency comm

202、unicationsVR:Virtual RealityWG:Work GroupWI:Work ItemXR:Extended RealityAcronyms Extended Reality and 3GPP Evolution 27Acknowledgments5G Americas Mission Statement:5G Americas facilitates and advocates for the advancement and transformation of LTE,5G and beyond throughout the Americas.5G Americas Bo

203、ard of Governors members include Airspan Networks,Antel,AT&T,Ciena,Cisco,Crown Castle,Ericsson,Intel,Liberty Latin America,Mavenir,Nokia,Qualcomm Incorporated,Samsung,Shaw Communications Inc.,T-Mobile USA,Inc.,Telefnica,VMware and WOM.5G Americas would like to recognize the significant project leade

204、rship and important contributions of group leader Orlett Pearson,Senior Specialist Standardization at Nokia and Diana Maamari Staff Engineer at Qualcomm,along with many representatives from member companies on 5G Americas Board of Governors who participated in the development of this white paper.The

205、 contents of this document reflect the research,analysis,and conclusions of 5G Americas and may not necessarily represent the comprehensive opinions and individual viewpoints of each particular 5G Americas member company.5G Americas provides this document and the information contained herein for inf

206、ormational purposes only,for use at your sole risk.5G Americas assumes no responsibility for errors or omissions in this document.This document is subject to revision or removal at any time without notice.No representations or warranties(whether expressed or implied)are made by 5G Americas and 5G Am

207、ericas is not liable for and hereby disclaims any direct,indirect,punitive,special,incidental,consequential,or exemplary damages arising out of or in connection with the use of this document and any information contained in this document.Copyright 2022 5G Americas Extended Reality and 3GPP Evolution

208、 28Endnotes1 TR 26.928,“Extended Reality(XR)in 5G”2 M.Abrash,“Creating the future:Augmented reality,the next human machine interface,”in IEDM Tech.Dig.,San Francisco,CA,USA,Dec.2021,pp.919.3 https:/www.bell- 5G Americas Member Company5 https:/ https:/www.bell- Chaccour,C.,Saad,W.(2021).Edge Intellig

209、ence in 6G Systems.In:,et al.6G Mobile Wireless Networks.Computer Communications and Networks.Springer,Cham.https:/doi.org/10.1007/978-3-030-72777-2_128 Intro to the Metaverse,Newzoo Trend Report 20219 https:/www.bell- Accenture 2020,https:/ Education TEDxCERN-https:/ https:/www.nist.gov/ctl/pscr/au

210、gmented-reality-public-safety12 https:/ https:/ https:/ 15 F.Hu,Y.Deng,W.Saad,M.Bennis and A.H.Aghvami,“Cellular-Connected Wireless Virtual Reality:Requirements,Challenges,and Solutions,”in IEEE Communications Magazine,vol.58,no.5,pp.105-111,May 2020,doi:10.1109/MCOM.001.190051116 K.Doppler,E.Torkil

211、dson,J.Bouwen,“On wireless networks for the era of mixed reality”,EUCNC 201717 C.Chaccour,M.N.Soorki,W.Saad,M.Bennis and P.Popovski,“Can Terahertz Provide High-Rate Reliable Low-Latency Communications for Wireless VR?,”in IEEE Internet of Things Journal,vol.9,no.12,pp.9712-9729,15 June15,2022,doi:10

212、.1109/JIOT.2022.3142674.18 C.Chaccour,M.N.Soorki,W.Saad,M.Bennis,P.Popovski and M.Debbah,“Seven Defining Features of Terahertz (THz)Wireless Systems:A Fellowship of Communication and Sensing,”in IEEE Communications Surveys&Tutorials,vol.24,no.2,pp.967-993,Secondquarter 2022,doi:10.1109/COMST.2022.31

213、43454.19 Chaccour,C.,&Saad,W.(2020,December).On the ruin of age of information in augmented reality over wireless terahertz(THz)networks.In GLOBECOM 2020-2020 IEEE Global Communications Conference(pp.1-6).IEEE.20 https:/ TR 26.928,Extended Reality(XR)in 5G22 TR 26.928,Extended Reality(XR)in 5G23 TR

214、23.758 Study on application architecture for enabling Edge Applications24 VR Wireless Requirements25 TR 26.928 Extended Reality(XR)in 5G26 S2-220185127 3GPP,New SID for Release 18“Study on XR Enhancements for NR”,RP-213587,Dec.2021 Extended Reality and 3GPP Evolution 2928 Petrov,Vitaly&Gapeyenko,Margarita&Paris,Stefano&Marcano,Andrea&Pedersen,Klaus.(2022).Extended Reality(XR)over 5G and 5G-Advanced New Radio:Standardization,Applications,and Trends.29 3GPP,New SID for Release 18“Study on XR Enhancements for NR”,RP-213587,Dec.202130 SP-21004331 SP-21116632 https:/ R1-220505334 SP-220353