TelePresence

Description

TelePresence (TP) in the 3GPP context is not a single protocol but a comprehensive service concept and framework for immersive, real-time multimedia communication. It is defined across multiple specifications covering service requirements, architecture, charging, and management. TP services go beyond traditional video conferencing by aiming to provide a psychologically convincing sense of "being there" and "being together" with remote participants. This involves a multi-sensory experience integrating ultra-high-definition (e.g., 4K, 8K, or 360-degree) video, high-fidelity spatial or binaural audio that conveys direction and distance, and potentially haptic or other interactive media streams.

Architecturally, TP services leverage the IP Multimedia Subsystem (IMS) as the core control and signaling framework for session establishment, management, and tear-down. The media flows for TP, however, place extreme demands on the transport network. These flows may be routed through Media Resource Function (MRF) entities for processing (e.g., video composition, audio mixing) or may use point-to-point or multi-point real-time transport protocols. Key architectural components involved include the UE (which must support high-end cameras, displays, and codecs), the policy and charging control (PCC) framework to ensure appropriate QoS, and the 5G Core Network's support for network slicing and edge computing.

From a technical operation perspective, a TP session begins with IMS-based signaling (SIP) to negotiate session parameters, including supported media types, codecs, bitrates, and QoS requirements. The PCC framework is invoked to establish dedicated QoS flows in the 5G system, guaranteeing the necessary bandwidth, priority, and packet delay budget. The media streams are then transported using protocols like RTP/RTCP over UDP/IP. Advanced codecs such as HEVC/H.265 or VVC/H.266 are essential for compressing the massive video data. A critical aspect is end-to-end latency, which must be kept extremely low (ideally below a few tens of milliseconds) to maintain natural interaction and avoid the feeling of lag. This often necessitates the use of Mobile Edge Computing (MEC) to host TP application servers closer to the users, minimizing transport delay. Furthermore, TP may utilize network slicing to create a virtual network instance with guaranteed resources isolated from other traffic, ensuring consistent performance.

Purpose & Motivation

TelePresence was created to address the limitations of existing video communication tools, which often suffer from low resolution, poor audio quality, noticeable latency, and a flat, non-immersive experience that fails to foster genuine collaboration. The business and social motivation was to enable remote interactions that are as effective as face-to-face meetings, thereby reducing travel, improving productivity, and enabling new forms of remote collaboration, education, and telemedicine.

Historically, as broadband internet and mobile networks evolved, simple video calling became possible, but it remained a poor substitute for physical presence. The rise of high-definition displays and advanced codecs created the technological foundation for something more immersive. 3GPP began standardizing TP to ensure interoperability across networks and devices, and to define the network capabilities required to support it. This was particularly important as 5G was being designed, as TP became a key driver for 5G's enhanced Mobile Broadband (eMBB) and Ultra-Reliable Low-Latency Communication (URLLC) service categories.

The problems TP aims to solve are multifaceted: technical (requiring networks to support unprecedented throughput and latency), experiential (creating a natural sense of presence), and commercial (defining charging models and interoperability standards). It addresses the limitation of previous "video conferencing" by treating immersion as a first-class service requirement, pushing the entire system—from UE capabilities to core network QoS mechanisms—to evolve. Its standardization ensures that a TP service from one vendor can work seamlessly with UEs and networks from other vendors, fostering a competitive ecosystem and widespread adoption.