Holographic-type communication: A new challenge for the next decade

Holographic-Type Communication (HTC) is an important technology that will be supported by 6G and beyond wireless systems. It provides truly immersive experiences for a large number of novel applications, such as holographic telepresence, healthcare, retail, education, training, entertainment, sports, and gaming, by displaying multi-view high resolution 3D holograms of humans or objects/items and creating multi-sensory media (mulsemedia), including audio, haptic, smell, and taste. HTC faces great challenges in transmitting high volume data with guaranteed end-to-end latency which cannot be addressed by existing communication and networking technologies. The contribution of this paper is two-fold. First, it introduces the basics and generic architectures of HTC systems. The encoding and decoding of hologram and mulsemedia are discussed, and the envisioned use cases and technical requirements are introduced. Second, this paper identifies limitations of existing wireless and wired networks in realizing HTC and points out the promising 6G and beyond networking technologies. Particularly, for HTC sources, the point cloud encoding and mulsemedia creation and synchronization are introduced. For HTC networking, new directions and associated research challenges, such as semantic communications, deterministic networks, time sensitive networks, distributed encoding and decoding, and predictive networks, are discussed as they may enable high data rate communications with guaranteed end-to-end latency. For HTC destinations, the heterogeneity of HTC devices, synchronization, and user motion prediction are explored and associated research challenges are pointed out. Video communication with 2D content has profoundly changed our daily life and workin style. HTC is an advanced technology that provides 3D immersive experiences, which will become the next research frontier.