Guest Editorial Signal Processing for Digital Twin in 6G Multi-Tier Computing Systems

Digital twin (DT) has become a game-changing tech- nology in many smart applications, including smart cities, manufacturing, automotive, gaming, entertainment and climate resilience. DTs help push the boundaries of system reliability and are used to support a wide range of func- tions such as diagnostics and fault prediction. Keeping DT up-to-date requires communication means with low latency, high reliability, and high data security protection. The digital virtual twins of physical systems are then used to optimize performance of the system in real time, and one example for such systems is the sixth-generation (6G) wireless networks. There are many challenges in representing a physical system virtually, such as true reflection of attributes, entanglement and composability. Entanglement refers to the truly complete exchange of information between physical objects and their logical twins, while composability deals with using the ex- isting twins of different entities to enable a complete twin- based service. A typical 6G service can be deployed using either a single or multiple twin objects. Multi-tier computing enables the distributed smart devices using the signal pro- cessing and wireless communication techniques to share their idle computing and storage resources, realising the efficient utilisation of multi-tier resources. The sharing of computing, communication and caching resources in multi-tier computing systems is maturing with the continuous development of signal processing and wireless communication technology to create an intelligent interconnected world for the metaverse.