# A Survey of the Real-Time Metaverse: Challenges and Opportunities +
## 8 Challenges and Opportunities
### Scalability  
The scalability of immersive technologies, such as VR and AR, is a major concern for the metaverse. Immersive platforms are highly resource-intensive, requiring vast amounts of computational power, bandwidth, and storage to render detailed, interactive 3D environments in real-time [278; 279]. As the user base grows, the system's ability to support an increasing number of concurrent users without compromising performance becomes a significant challenge. For instance, social VR platforms like VRchat or Facebook's Horizon Worlds often experience server overloads, resulting in degraded user experience due to lag, buffering, or crashes when large numbers of users are interacting simultaneously. The fact that immersive experiences necessitate the transmission of high-resolution 3D content, which necessitates significant bandwidth to maintain seamless user interaction, makes this problem worse. For example, high-resolution 3D models, complex textures, and lighting effects need to be transmitted and rendered in real-time, which places a heavy burden on both the network infrastructure and the user's hardware. The need for real-time synchronization of users' actions and environmental changes within the metaverse further complicates the scalability issue [280]. In a fully immersive experience, every user's movement, interaction, and even facial expressions must be reflected in real-time for all other participants. This requires not only high bandwidth but also extremely low latency to avoid noticeable lag, which can severely disrupt immersion. The concept of \"presence\"--a core aspect of VR that makes users feel as though they are truly inside a virtual environment--depends on these real-time interactions being smooth and instantaneous. Any delay in transmitting data between users or in rendering updates to the virtual world can break the illusion, reducing the effectiveness of the immersive experience. While current network infrastructures have seen improvements with the advent of 5G, they still face limitations in supporting the data-heavy demands of immersive systems [85]. 5G promises ultra-low latency (around 1 millisecond) and higher data rates, but even this technology may struggle under the demands of a fully populated metaverse, where thousands or even millions of users interact simultaneously. For example, the bandwidth required for real-time rendering of high-definition 3D environments and live interactions can exceed what current 5G networks can handle at scale. In large virtual events, such as live concerts or digital sports games, the number of concurrent users may push network capacity beyond its limits, resulting in a laggy or interrupted experience for many participants. In addition to network constraints, processing power remains a critical bottleneck [281]. Rendering real-time 3D environments, especially at the quality expected in high-end VR applications, requires significant computational resources. Current GPUs (graphics processing units) are already strained in handling the complex tasks required for real-time ray tracing, realistic physics simulations, and AI-driven interactions. In a fully immersive metaverse, these requirements scale exponentially as the number of users increases. Real-time data fusion, which integrates inputs from multiple sensors (e.g., motion tracking, facial recognition, and environmental mapping), requires extensive computational power. This is especially true for systems aiming to provide haptic feedback or real-world physics, where even minor delays can degrade the overall experience. Additionally, the diversity of devices and platforms presents another scalability challenge. Users will access the metaverse using a wide range of devices, from high-end VR headsets to mobile phones and desktop computers [267]. Each device has different processing capacities, display resolutions, and input methods, which makes it difficult to standardize the user experience.