# A Survey of the Real-Time Metaverse: Challenges and Opportunities +
## 1 Introduction  
The metaverse is a complex, multi-component, hierarchical construct integrating various technologies and systems to create an immersive, three-dimensional (3D) interconnected virtual universe [1]. Figure 1 illustrates a seven-layer architecture of the metaverse. At its foundation, the _Infrastructure Layer_ is the technical backbone that ensures the metaverse operates smoothly and efficiently [2]. It includes the physical hardware like servers and data centers and the cloud computing resources that provide the necessary computational power. A robust infrastructure is essential for scalability, enabling the metaverse to grow and accommodate increasing users and experiences. The _Interface layer_ determines how users interact with the metaverse [3], which includes the devices they use, such as VR headsets, AR glasses, and smartphones, as well as the software interfaces that make the metaverse accessible and user-friendly [1]. A well-designed interface is key to ensuring that the metaverse is easy to navigate and engaging, making it accessible to a wide range of users, regardless of their technical expertise. The core of the metaverse is the _Decentralization layer_, which ensures that the metaverse operates without being controlled by a single entity. The decentralization layer is crucial for maintaining user autonomy, privacy, and security, often achieved through blockchain technology [4]. By distributing power and data across a network of users, decentralization enables true ownership of digital assets, allowing participants to engage in transactions and interactions with confidence that their data and property are secure [5]. _Spatial computing_ plays an essential role in a metaverse, which merges the physical and digital worlds to create immersive experiences. The computing layer utilizes technologies like virtual reality (VR) [6], augmented reality (AR) [7], mixed reality (MR) [8], and haptic feedback systems [9], allowing users to interact with digital objects as if they were part of the physical world. Spatial computing makes the metaverse more tangible and real, enabling users to experience and manipulate 3D environments in ways that go beyond the limitations of traditional computing interfaces [10]. _The Creator Economy_ layer is the engine that drives innovation and content within the metaverse [11]. This layer supports the tools and platforms that allow users to create, distribute, and monetize digital content and experiences [12]. The creator economy fosters a vibrant, self-sustaining ecosystem where creativity is rewarded by empowering individuals to produce and profit from their creations [13]. The creator's content fuels the diversity of experiences available and encourages continual growth and expansion of the metaverse. _The Discovery layer_ helps users navigate the vast expanse of the metaverse [14]. It includes search engines, social networks, and recommendation systems that guide users toward content, experiences, and services that match their interests [15]. Effective discovery mechanisms are essential for helping users find and engage with what they are looking for, ensuring that the metaverse remains a dynamic and accessible space. Finally, the _Experiences layer_ is where the real value of the metaverse is realized [3]. It encompasses all the activities users can participate in, from socializing and gaming to education and commerce. The quality and variety of these experiences make the metaverse  
Figure 1: An illustration of the 7-layer metaverse architecture. an engaging and appealing place for users to spend their time. The experience layer is constantly evolving, driven by the creativity of the community and the opportunities enabled by the other layers. The metaverse is driven by several key technologies that collectively create an immersive, interactive, and interconnected nature [16], as conceptually shown in Figure 2. Blockchain technology underpins the decentralization and security aspects of the metaverse [17].