The content of this section is derived from the first of two deliverables under Work Package 4 (WP4), D4.1., a key component of the broader research and development effort aimed at enhancing the XR (Extended Reality) and spatial computing ecosystem.
The overarching goal of WP4 is to co-create an Interoperability Guidance Document that will serve as a foundational reference for various stakeholders in the XR and spatial computing domain. This document is intended to inform policy-makers, developers, platform providers, researchers, and others working at the intersection of immersive technology and spatial computing systems.

One of the primary objectives of WP4 is to map existing and emerging requirements for interoperability within the XR and spatial computing domains. These technologies are rapidly evolving, and interoperability—the ability of different systems, devices, applications, and platforms to communicate, exchange, and use information effectively—has become a critical concern. As XR experiences become increasingly integrated into our daily lives, spanning areas such as education, healthcare, manufacturing, public services, and entertainment, the absence of robust interoperability standards can limit accessibility, innovation, and user inclusion.

The report, referred to as Deliverable 4.1 (D4.1), provides a comprehensive overview of the current state of interoperability in XR and spatial computing. Specifically, it examines infrastructure, platforms, content formats, development tools, and system-level requirements that underpin the XR ecosystem. The deliverable places particular emphasis on the effects of interoperability (or lack thereof) on accessibility—a critical issue when designing XR experiences that must be inclusive and usable by individuals with varying abilities and needs.

To conduct this analysis, the WP4 team employed a Systematic Literature Review (SLR) methodology. The SLR was used to gather, analyze, and synthesize existing knowledge from a wide range of sources, including academic publications, technical reports, white papers, industry guidelines, policy briefs, and surveys. This rigorous method allows for a well-structured, repeatable assessment of the current landscape, ensuring that the findings presented in D4.1 are both reliable and comprehensive.

A key focus of this report is to identify existing, emerging, and new standards relevant to XR and spatial computing. These include interoperability standards across different layers of the technology stack—from data formats and communication protocols to identity management, content rendering, spatial anchoring, and environmental understanding. The analysis also maps ongoing standardisation efforts by various organisations, such as the Open Geospatial Consortium (OGC), IEEE, W3C, and Khronos Group, to name a few.

Beyond technical interoperability, the report also addresses semantic and organisational interoperability, examining how data meaning and institutional practices affect the sharing and integration of spatial information. This broader perspective is vital for ensuring that XR systems are not only technically aligned but also able to interoperate in terms of data semantics, governance, privacy, and user expectations.

D4.1 also explores the challenges and gaps that continue to hinder progress in this area. These include a lack of unified frameworks, fragmented standards adoption across regions and sectors, proprietary platforms that restrict open integration, and the absence of legal and ethical guidelines to support equitable access to XR technologies. These barriers have downstream effects on accessibility, with specific user groups—such as people with disabilities or those in low-connectivity regions—often excluded from the full benefits of immersive experiences due to incompatible systems or insufficient design considerations.

This deliverable is intended to support the work of other WPs in the larger project, including but not limited to WP3, WP5, and WP6. By synthesising and evaluating existing interoperability knowledge and practices, D4.1 provides a crucial input into future research activities, development goals, and policy recommendations. The insights from this report will be instrumental in the formulation of the Interoperability Guidance Document in D4.2, which will translate technical findings into actionable guidance for stakeholders.

In summary, Deliverable 4.1 lays the groundwork for advancing interoperability in XR and spatial computing by presenting a clear and comprehensive picture of the current state, challenges, and future directions. It emphasises the interconnectedness between interoperability and accessibility,< aiming to foster a more inclusive, standards-based XR ecosystem. Through systematic research and critical analysis, this report informs future developments and serves as a strategic resource for shaping a more interoperable and accessible future for XR technologies