This document defines the "mobile metaverse" as the user experience enabled by the 5G system of interactive and/or immersive XR media, including haptic media. For clarity and unambiguity with respect to many divergent technical and commercial developments, this document avoids the use of the term "metaverse" without qualification with the term "mobile". This annex provides background information for the present document and further explanation of the term mobile metaverse, and the services that it enables. The term mobile metaverse implies the combination of various technologies to fuse physical and digital worlds, widely impacting society and the economy. Users will access these mobile metaverse services with devices for interaction with XR media and sensors, enabled by mobile telecommunication standards. Mobile metaverse services are expected to be provided via many and diverse service providers, each catering to different customers, companies and communities. An entertainment company might provide one mobile metaverse service for consumers such as a virtual theme park, while offering a separate mobile metaverse service to its employees. Some providers may specialize in interactive tools to create content, while others present that content. In general, mobile metaverse services can be divided into three general categories: industrial, enterprise and consumer mobile metaverse services. There are commonalities among these categories. These mobile metaverse services will apply across these domains to varying degrees, sharing technologies, devices and interfaces, and functionalities described in this document. Ultimately, mobile metaverse services will be defined by the applications they enable and the business models they adopt. Besides "experiencing" virtual world and/or augmented real world media as a passive consumer (where the media is read-only), mobile metaverse services also can enable interaction, the user can "create" and even "control" elements of the media. Depending on the mobile metaverse service, the consequence of user interaction could be experienced by other users. As discussed below, in some cases, user interaction may result even in changes to the real world, through 'actuation' (remote control mechanisms) as discussed in clause A.4. Mobile metaverse services face technical challenges specific to the media and interactions they offer to users, in the context of mobile networks. Some of these technical challenges are addressed by mobile telecommunications standards, of which this document is a contribution. Another set of challenges are not technical in nature, such as regulatory and safety implications, only some of which are discussed in the present document. Other technical and non-technical challenges are expected to be addressed separately depending on the target environment/vertical.

There has been some initial development of commercial consumer-oriented mobile metaverse services, specifically in metaverse gaming and VR social media 'virtual worlds'. Mobile metaverse consumer services considered during the study of mobile metaverse services relate to the following use cases:

• Attending (live) VR events (sports, gaming, concerts, etc.) either as spectator or performer, including while moving / commuting;
• Virtual shopping or visit experience (tourism, real estate, etc.);
• Presentation of AR content on a virtual screen, e.g., a feature length movie;
• Interaction with AR content in a location-aware manner, offering spatial localization and mapping to support applications generating AR content for enhanced localized experiences (e.g., in museums, shopping malls);
• Situation awareness about the user's physical surroundings, while walking or driving;
• Experience immersive communications with other entities - digital representations of users or application-generated content, including customer support services, by leveraging avatars, digital assets and wallets.

Remote working has driven demand for better collaboration and communication tools, and thanks to extended reality (XR) and virtual reality (VR) technologies, many of those tools contribute to the enterprise metaverse. The enterprise mobile metaverse will eventually envelop the core productivity applications that make business function, e.g., as a digital drafting tool for architecture and engineering, and training sessions via AR and/or VR. Eventually, the enterprise and industrial mobile metaverses will interlink, merging the IT systems in office branches with the Operational Technology (OT) systems of the shop floor. Main mobile metaverse enterprise services considered during the study of mobile metaverse services relate to the following use cases:

• XR-enabled collaborative and concurrent engineering based on geospatial digital twins (and avatars), for research & prototyping, visual testing & simulation, planning & optimisation, which can further be used for training
• Virtual showrooms, products or stores;
• Interaction with AR content in a location-aware manner, e.g., creating spatial anchors and discovery of them for AR content enhanced in-store shopping experiences;

Industrial mobile metaverse services are expected to provide cost, productivity, safety and flexibility gains. In particular, industrial OT systems begin to support mobile services that include XR media for monitoring and analysis, and also for control of operations through the digital orchestration of robot fleets or user-guided remote operations. Industrial users will gain the ability to visualize and reconfigure their operations, e.g., in response to changing supply and demand or disruptions. By fusing digital and physical realities, the digital twin has begun to transform many industries. Seaports have begun using digital twins to track every container on their docks. Aerospace companies design and build engines and fuselages virtually to simulate how an aircraft will fly and perform. Many new factories exist just as much digitally, as data and virtual representation, as they do in the physical world. This kind of mobile metaverse service aims at control and awareness of operations down to the smallest detail. Some of the mobile metaverse service enabler requirements support digital twin applications. Main mobile metaverse industrial services considered during the study of mobile metaverse services relate to the following use cases:

• Remote critical health care, including surgery and treatment;
• AR/VR based tele-operation of a remote device or vehicle (e.g., driving).

Common enablers associated with mobile metaverse services are virtual, augmented, mixed and other media (expressed collectively as extended reality, XR.) Whilst these are essential to the realization of the immersive experience of mobile metaverse services, they are not the only enabling functionalities. This document does not focus on XR media and media services per se, but rather identifies requirements for complementary enablers common to all mobile metaverses services, including:

• Enabling localized (i.e., location-aware) mobile metaverse services by considering the essential mobility aspect of 5G connectivity, and collection and exposure of sensor data or 'results of processed sensor data' as needed by mobile metaverse services to integrate media into an immersive user's experience and expectations;
• Enhancing real-time communications, including over IMS, with avatar-based capabilities, thus allowing more immersiveness in virtual reality, augmented reality, etc. user experiences;
• Enhancing XR media delivery to make it possible to support user experience of multiple services simultaneously;
• Securely storing, exposing and managing digital assets.

Other key enablers of the metaverse implied by some immersive experiences relate to digital twins, defined in this document as "a real-time representation of physical assets in a digital world". With respect to the metaverse, "geospatial" digital twins relate to the concept of adding geospatial information to a digital twin, such as 3D models, precise location and temporal information - enabling for example holographic-type of object animation. The value proposition of geospatial Digital twins is about enabling immersive user experience, collaboration and simulations that are very close to what to expect in the real world by all 3 categories of mobile metaverse services. It is foreseen that additional functionalities will be defined in the future to provide capabilities to better offer and operate mobile metaverse services.