# A Survey of the Real-Time Metaverse: Challenges and Opportunities +
## 1 Introduction
Blockchain ensures that digital assets, including virtual currencies, property, and identities, are securely managed and owned by users without relying on centralized authorities [18]. Blockchain technology provides transparency, immutability, and trust, enabling users to engage in secure transactions and interactions within the metaverse [19]. By leveraging blockchain, the metaverse can maintain a fair and open economy where users have full control over their digital assets and data. Augmented reality (AR) and virtual reality (VR) are at the forefront of creating immersive experiences within the metaverse [20]. VR creates fully digital environments that users can explore and interact with using devices like headsets and gloves, effectively transporting them to another world. AR, on the other hand, overlays digital content in the real world, enhancing users' perceptions and interactions with their surroundings [21]. Together, AR and VR provide the sensory and spatial components that make the metaverse feel tangible and engaging, allowing users to interact with digital spaces in ways that mimic real-world experiences. 5G is essential for enabling the metaverse due to its ultra-high-speed connectivity and low latency [22]. This technology allows for seamless, real-time interactions within virtual environments. It supports high-bandwidth applications like augmented reality (AR), virtual reality (VR), and 3D reconstructions by providing faster data transfer, improving the user experience even in highly populated virtual spaces [23]. It also enables advanced features like haptic feedback in virtual reality, enhancing immersion by allowing users to \"feel\" virtual objects or textures. Artificial intelligence (AI) technologies drive the intelligence and responsiveness of the metaverse [24]. AI powers various aspects of the metaverse, including creating realistic virtual characters to interact with users and generating dynamic and adaptive  
Figure 2: Metaverse technologies. environments [25]. AI also plays a crucial role in personalization, learning from users' behaviors and preferences to tailor experiences that meet individual needs. By enabling complex decision-making and learning within the metaverse, AI ensures that the digital world is not only immersive but also intelligent and responsive. Brain-computer interfaces (BCIs) allow users to interact with virtual environments through brain signals, bypassing traditional input methods like keyboards or controllers [26]. This technology, while still in its early stages, has the potential to revolutionize the metaverse by enabling thought-based commands and avatar control. Early applications in gaming and productivity could lead to a more immersive and efficient experience. More people may use BCIs, which connect directly to the human neocortex and allow for advanced cognitive functions and interaction in virtual spaces [27]. Internet of Things (IoT) technology bridges the gap between the physical and digital worlds by connecting real-world edge devices to the metaverse [28]. IoT technology allows physical objects, from home appliances to vehicles, to communicate and interact with the digital environment. IoT integration enables real-time data exchange and interaction, making the metaverse a more seamless extension of the physical world [2; 29]. For instance, IoT can allow users to control real-world devices within a virtual environment or bring physical data into the metaverse for analysis and visualization. Similarly, 3D reconstruction technology is vital in creating detailed and accurate digital representations of real-world environments [30]. This technology captures and digitizes physical spaces, objects, and people, bringing them into the metaverse with high fidelity. Three-dimensional (3D) reconstruction allows for creating virtual replicas of real-world locations, enabling users to explore and interact with these spaces as if they were physically present [31].