INTAREA C. Sarathchandra Internet-Draft M. Kheirkhah Intended status: Informational M. Ghassemian Expires: January 13, 2022 InterDigital Europe, Ltd. July 12, 2021 Tactile Internet Service Requirements draft-sarathchandra-tactile-internet-01 Abstract The Tactile Internet refers to a new communication paradigm, which can provide low-latency, reliable and secure transmission for real- time information such as control, touch, and sensing/actuation in emerging tactile internet applications like teleoperation, immersive virtual reality, and haptics communications. The main goal of this document is: 1) to briefly introduce tactile internet background and use cases; 2) to identify potential service requirements that can be addressed at the IETF or researched at the IRTF. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 13, 2022. Copyright Notice Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect Sarathchandra, et al. Expires January 13, 2022 [Page 1] Internet-Draft Tactile Internet Service Requirements July 2021 to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Abbreviations List . . . . . . . . . . . . . . . . . . . . . 3 4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4.1. Industry . . . . . . . . . . . . . . . . . . . . . . . . 4 4.2. Healthcare . . . . . . . . . . . . . . . . . . . . . . . 4 4.3. Entertainment . . . . . . . . . . . . . . . . . . . . . . 4 4.4. Training . . . . . . . . . . . . . . . . . . . . . . . . 5 5. User Equipment Capabilities . . . . . . . . . . . . . . . . . 5 6. TI Service Requirements . . . . . . . . . . . . . . . . . . . 6 6.1. Haptic Media Type . . . . . . . . . . . . . . . . . . . . 6 6.2. Ultra-Low Latency . . . . . . . . . . . . . . . . . . . . 6 6.3. Ultra-High Reliability . . . . . . . . . . . . . . . . . 7 6.4. Synchronization . . . . . . . . . . . . . . . . . . . . . 7 6.5. Application-Network Interaction . . . . . . . . . . . . . 7 6.6. Multi-Modal Coordinated Parallel Transmission . . . . . . 8 6.7. Personalised Multi-Modal Experiences . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 9. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 9 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 11.1. Normative References . . . . . . . . . . . . . . . . . . 10 11.2. Informative References . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 1. Introduction Tactile Internet (TI) was defined as a new wave of innovation after the successful Internet of Things (IoT) [ITU-T2014]. In fact, Tactile Internet (TI) can be regarded as a new ICT paradigm with extreme emphasises and service requirements on multiple performance metrics such as latency, availability, reliability, and security.TI finds its application in many emerging application scenarios, including, but not limited to, Industry, Robotics and Telepresence, eXtended Reality (e.g., Augmented Reality, Virtual Reality and Mixed Reality), Healthcare, Gaming, and Teleoperation. These extreme service requirements from TI applications pose new challenges to both communication and computing. Although existing networking architecture and protocols can support some of these Sarathchandra, et al. Expires January 13, 2022 [Page 2] Internet-Draft Tactile Internet Service Requirements July 2021 service requirements partially (e.g., 5G URLLC [URLLC-3GPP]), a still pending question is whether and how a holistic and systematic approach should be developed in order to efficiently support TI applications. Moreover, IEEE 1918.1 standards working group [IEEE19181] on TI is formed to investigate aspects related to TI applications, architecture and haptic encoding. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 3. Abbreviations List o TI - Tactile Internet o TD - Tactile Devices o UE - User Equipment o URLLC - Ultra-Reliable Low-Latency Communications o AR - Augmented Reality o VR - Virtual Reality o PPE - Personal Protective Equipment o ISOBMFF - ISO Base Media File Format o QoE - Quality of Experience o QoS - Quality of Service o AES - Advanced Encryption Standard o WEP - Wired Equivalent Privacy o WPA - Wi-Fi Protected Access 4. Use Cases This section aims to introduce the reader to distinct, although not exhaustive, TI applications which are widely being discussed in the TI research community. Sarathchandra, et al. Expires January 13, 2022 [Page 3] Internet-Draft Tactile Internet Service Requirements July 2021 4.1. Industry Automation, smart factories and remote operation are some of key industry use cases that are enabled by TI [IndustryTI]. Moreover, repair and maintenance in remote areas, in high-risk scenarios requiring high precision requires multi-modal [TactileMultimodal-3GPP] and low latency communication provided by TI. For example, in such scenarios, human operators can control machinery (e.g., robots) remotely and perform complex operations [IndustryRobot], where either it is too dangerous for humans to be present, or it's not possible for the experts to be physically present at the environment where the operations are conducted. The controlled machinery may be equipped with various sensors for providing information about the environment to the operator, while it may also be equipped with required actuators for performing corresponding tasks as instructed by the constructor over the TI. TI may also enable the transmission of critical information (e.g., alerts) to human users (e.g., through connected PPE as AR and haptic data) who perform operations in high-risk environments. Alerts may be automatically generated based on information gathered from sensors, or sent by human users, over the TI. 4.2. Healthcare Key health applications of TI include, tele-surgery [Independent], tele-mentoring, tele-rehabilitation and tele-diagnosis [TIAijaz2019]. Specifically, minimising the invasive nature of surgery has been a focus of the heath technology industry and has currently been widely used due to the small tissue damage and fast recovery it incurs.Today, surgeons use surgical robots for performing highly precise operations. Providing tactile feedback is specifically critical for performing operations which require high precision manipulation. Although, it is not always possible to get specialist surgeons on site for performing operations on patients, TI enables surgeons to perform such critical operations remotely, where it requires only the machinery (high precision robots) to be co-located alongside the patient. 4.3. Entertainment The advancements in Augmented Reality (AR) & Virtual Reality (VR) technology as well as the increased number of applications developed for user entertainment (e.g., VR gaming, VR tourism, VR art) have significantly increased the interest for further improving the immersive experiences those application provide. VR applications enable human users, or a collection of human users to interact with a virtual environment where the provided immersive experience is similar to that of a real physical interaction. Haptic feedback is a Sarathchandra, et al. Expires January 13, 2022 [Page 4] Internet-Draft Tactile Internet Service Requirements July 2021 key element in such interactions, allowing the user to experience the sense of touch along with audio and visual(e.g., users perceiving the effect of each other's actions in collaborative scenarios). 4.4. Training TI enables learning experiences where tactile feedback plays a crucial role. This may substantially improve both the learning as well as the teaching experiences in remote learning scenarios. The teacher will be able to experience (see, hear, feel) actions performed by the learner and correct any errors as if they are in a real physical (face-to-face) learning environment. Such applications include, remote military and sports training [na2020simulation] which requires problem solving by collaborating with remote team members, while incorporating feedback provided by the remote trainer in real- time. Furthermore, Internet of Skills [InternetofSkills]application aims at training people in remote and diverse locations to improve their skills and capabilities. It combines advances in motor training and Tactile Internet with Human-in-the-loop to achieve the goal of transferring high quality skills to populations that otherwise do not have access to such training. Moreover, the goal of Surgical Assistance and training [SurgicalTraining] application is to develop a system that provides assistance to an expert surgeon during a surgery or to provide surgery training to students. Such a system is envisaged to be continuously learning and acquiring expert knowledge. To do this, the system interprets sensor data as it observes an expert surgeon performing their procedure. 5. User Equipment Capabilities Various sensors, actuators, display devices are used to provide a realistic haptic and multimodal interaction with the remote devices over a uni-directional or bi-directional communication. The sensor components capture the tele-manipulation instructions (e.g., kinaesthetic), and the resulting changes (e.g., haptic feedback). Actuators execute the user's tele-manipulation instructions. The number of independent coordinates used for providing the end user experiences (using Human System Interfaces), and for controlling the velocity, position, and the orientation of the controlled devices is defined by their degree of freedom (DoF). Capabilities of UEs in collecting biometrics can enhance security solutions (such as user identification and authentication). While existing authentication mechanisms relay on SIM (subscriber identity module or subscriber identification module) cards in mobile devices, unique biometrics collected from the users can be used to enhance the security. Considering a scenario where the SIM card token is stolen, an alternative/complementary method of ensuring network connectivity Sarathchandra, et al. Expires January 13, 2022 [Page 5] Internet-Draft Tactile Internet Service Requirements July 2021 for the genuine user would involve the use of biometrics as these cannot easily be stolen. Biometrics offers a solution to the weaknesses of knowledge and token-based systems. Examples of continuous biometrics are face, iris, keystroke dynamics, touchscreen gestures, behavioural profiling (e.g. Bluetooth/Wifi/GPS), gait, mood and one-shot biometrics are face, iris, and fingerprint that can be collected by the new UE. 6. TI Service Requirements As a result of the research and developments in TI, this section presents service requirements to be addressed by the networking community. 6.1. Haptic Media Type Unlike audio and video, there has not been any haptic media types in standards, until a very recent development in standards to register haptics as a top-level media type. A proposal to introduce haptics as a first-order media type in ISO Base Media File Format (ISOBMFF) was accepted by MPEG Systems File Format sub-group. This standardization process is expected to conclude in October 2021, making haptics a part of the ISO/IEC 14496-12 (ISOBMFF) standard. Providing this recent development, the authors [I-D.muthusamy-dispatch-haptics] make a case for haptics to be added to the list of top-level media types recognised by the IETF. The authors further argue that 'application' top-level type not suitable for haptics as, like audio/video haptics is related to a separate sensory system. Moreover, 'application' is historically used for application code, and haptics is not code but a property of a media stream (like audio and video). Therefore, we believe that the adoption of a top-level haptics media type in IETF is an important step towards further development of haptic communication. 6.2. Ultra-Low Latency Most Haptic applications demands stringent latency requirements from the underlying communication. Specifically, ultra-low latency, 1ms for haptic interaction [ITU-T2014], is demanded for providing timely delivery of messages between communicating devices by TI applications. The timely delivery of control messages is crucial for critical TI applications such as TI remote surgery. Moreover, timely delivery of messages also assists in playback of multi modal [TactileMultimodal-3GPP] streams (audio, video, haptic) in a synchronous manner, providing a consistent experience that is devoid of cybersickness. Sarathchandra, et al. Expires January 13, 2022 [Page 6] Internet-Draft Tactile Internet Service Requirements July 2021 6.3. Ultra-High Reliability Ultra-high reliability is required by several TI applications. For example, it is not acceptable for communication reliability to be hindered during critical TI applications such as alert transmission for connected PPE (described Section Section 4.1). Thus, it is crucial that ultra-reliable communication is a key enabler of TI applications. 6.4. Synchronization The tactile applications often consist of several streams, e.g., audio, video, haptic, each stream with varying service requirements (bitrates, latency, level of reliability). Moreover, depending on the use case and the deployment scenario, streams of an application may be distributed among multiple tactile/terminal devices, e.g., video stream to display, audio stream to sound system, haptic stream to haptic suit. However, all such streams must be played back to the user in a synchronous manner when providing multi-sensory immersive experiences. Especially, in scenarios where a user uses multiple UEs/terminals for consuming the same user experience, media streams (haptic, audio, video) must be delivered and played to the user in a synchronous manner (e.g., avoiding Cybersickness [Promwongsa]). Due to network conditions and the insufficient support/assistance for synchronization, related streams may arrive at different UEs/ terminals out of synchronization (e.g., the lack of information related to inter-dependency among network flows [ITU-NET2030]). Therefore, mechanisms for the coordination (see section Section 6.6 for detailed discussion) and synchronization of multiple flows, for both the same destination/UE, and for multiple destinations/UEs must be introduced. 6.5. Application-Network Interaction Emerging TI applications are highly diverse in terms of their use case requirements and constraints. For example, a TI application may comprise multiple streams (e.g., due to multi-modal [TactileMultimodal-3GPP] nature), each of which may be required to be treated differently by the network based on their use case requirements and constraints; some streams may need high bandwidth and ultra-low latency while some others may require ultra-high reliability. The conventional interaction model between applications (end-hosts) and networks are insufficient to deliver the traffic of these emerging TI applications. In other words, applications should not consider the network as a black-box anymore and in turn they should not entirely rely on the end-to-end measurements for adapting Sarathchandra, et al. Expires January 13, 2022 [Page 7] Internet-Draft Tactile Internet Service Requirements July 2021 their behaviour as the underlying network condition changes rapidly, mainly because the end-to-end measurements are implicit and thus coarse-grained. To this end, a new collaborative paradigm between applications and networks need to be realized. This way, applications and networks can express their desired use case requirements and constraints to one another, permitting applications in particular to adapt themselves to network constraints and the networks to orchestrate their resource distribution according to the applications' requirements if desired. This is particularly essential for TI terminals which have to run highly diverse applications/services often with conflicting requirements. 6.6. Multi-Modal Coordinated Parallel Transmission Applications in TI typically follow a multi-modal communication [TactileMultimodal-3GPP] pattern in which the end-to-end communication between tactile devices (TDs) includes several modes of communication at the same time (e.g., video, audio and haptic). This results in generation of multiple coordinated streams in parallel which ultimately need to be presented to an end user in harmony. Otherwise, the quality of experience (QoE) of the user may not be satisfactory due to lack of precise synchronization across these parallel streams. For example, one stream may get delayed while others are delivered on time. Apart from the synchronization challenges (see also Section 5.4 for more detailed discussion), the instability of the underlying network condition of a stream may also impact the performance of the other coordinated parallel streams of the same TI application, which may ultimately reduce the overall QoE of users.Therefore, it is crucial to have mechanisms particularly tailored for coordination (e.g., data packet scheduling across multiple terminals and/or access networks) so that varying network condition across multiple networks can be intelligently handled. The key goal here is to distribute data packets without creating network congestion and/or increasing end-to-end delay. These type of communications can also significantly benefit when there is a feedback loop mechanism between TI applications (terminals) and networks (see Section Section 6.5 for more details). 6.7. Personalised Multi-Modal Experiences The TI use cases are highly dynamic in nature. Especially, in multi- user scenarios where user profiles, their dynamic relations and interactions are taken into consideration, e.g., virtual simulation environments used for training, where multiple users act upon the same virtual objects, the information received by individual 'trainee users' may differ due to 1) user preferences (e.g., with haptic Sarathchandra, et al. Expires January 13, 2022 [Page 8] Internet-Draft Tactile Internet Service Requirements July 2021 feedback vs without) 2) specific user's perception (e.g., audio, video haptic) of objects and actions/events within the virtual environment (e.g., based on viewpoint, distance to objects/events, and properties of virtual objects). Moreover, the trainer (human or virtual) may choose to provide corresponding feedback (using audio- visual or audio-visual-haptic mediums) to an individual or a group/ subset of trainees in real-time. Different users may receive different haptic feedback depending on the type of actions performed and therefore the experiences may differ for each user. When providing such experiences the resulting dynamicity must be considered. Therefore, the multi-modal information provided to each user, through data streams, may be personalised (e.g., based on distinct user perception and user profile). 7. IANA Considerations This document requests no IANA actions. 8. Security Considerations Security and trust as well as communication latency are key challenges for delivering tele-surgery. Conventional internet security protocols (namely, AES, WEP, WPA) are used to make the data transfer prone to attack. Security and reliability of the haptic data locally/remotely are key to Tactile Internet use-cases such as telesurgery use-case. Further work is required on security/privacy aware haptic data/feedback encoding techniques to improve the reliability and security of the TI use-cases. Furthermore, continuous monitoring demands low-power and reliable operation to avoid any interruption in data collection from power restricted devices and therefore the service delivery [monaICC2020]. 9. Conclusion This draft presents the emerging area of Tactile Internet, its key use cases and service requirements. The introduction of haptic communication, a new mode of communication, not only improves existing immersive experiences (e.g., AR/VR) while also facilitates new emerging Tactile immersive experiences (e.g., tele-surgery). Moreover, the resulting communication over the Tactile Internet demands for stringent service requirements on the underlying communication networks, e.g., ultra-high reliability, ultra-low latency transmission, security consideration and synchronization of multi-modal data (including haptic). Therefore, We believe IETF is a key forum for addressing some of the potential challenges described, Sarathchandra, et al. Expires January 13, 2022 [Page 9] Internet-Draft Tactile Internet Service Requirements July 2021 for realizing the envisioned Tactile Internet, and for standardizing relevant aspects such as protocols. 10. Acknowledgments The authors would like to thank Renan Krishna for reviewing and providing useful comments. 11. References 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . 11.2. Informative References [Holland] Holland, O. and el. al., "The IEEE 1918.1 "Tactile Internet" Standards Working Group and its Standards", Proceedings of IEEE , 2019, . [I-D.muthusamy-dispatch-haptics] Muthusamy, Y. K. and C. Ullrich, "The 'haptics' Top-level Media Type", draft-muthusamy-dispatch-haptics-01 (work in progress), November 2020. [IEEE19181] ITU Network 2030 Technical Report, "Network 2030 - Gap analysis of Network 2030 new services, capabilities and use cases", 2020, . [Independent] Independent News Article, "SURGEON PERFORMS WORLD'S FIRST REMOTE OPERATION USING '5G SURGERY' ON ANIMAL IN CHINA", 2019, . [IndustryRobot] ABmann, U. and et. al., "Human-robot cohabitation in industry", In Tactile Internet, Academic Press pp. 41-73, 2021. Sarathchandra, et al. Expires January 13, 2022 [Page 10] Internet-Draft Tactile Internet Service Requirements July 2021 [IndustryTI] Aijaz, A. and et. al., "The Tactile Internet for Industries: A Review", In Proceedings of the IEEE, 2019. [InternetofSkills] Oppici, L. and et. al., "Internet of Skills", In Tactile Internet, Academic Press pp. 75-99, 2021. [ITU-NET2030] ITU Network 2030 Technical Report, "Network 2030 - Gap analysis of Network 2030 new services, capabilities and use cases", 2020, . [ITU-T2014] ITU-T Technology Watch Report, "The Tactile Internet", 2014, . [monaICC2020] Ghassemian, M. and et. al., "Secure Non-Public Health Enterprise Networks", In 2020 IEEE International Conference on Communications Workshops (ICC Workshops), 2020. [na2020simulation] Na, W. and et. al., "Simulation and measurement: Feasibility study of Tactile Internet applications for mmWave virtual reality", In ETRI Journal 42.2 (2020): 163-174, 2020. [Promwongsa] Promwongsa, N. and el. al., "A Comprehensive Survey of the Tactile Internet: State-of-the-Art and Research Directions", IEEE Communications Surveys and Tutorials IEEE, 2021, . [SurgicalTraining] Spiedel, S. and et. al., "Surgical Assistance and Training", In Tactile Internet, Academic Press pp. 23-39, 2021. [TactileMultimodal-3GPP] 3GPP TR 22.847, "Study on supporting tactile and multi- modality communication services", 2021, . Sarathchandra, et al. Expires January 13, 2022 [Page 11] Internet-Draft Tactile Internet Service Requirements July 2021 [TIAijaz2019] Aijaz, A. and et. al., "The Tactile Internet for Industries: A Review", In Proceedings of the IEEE, 2019. [URLLC-3GPP] 3GPP TR 23.725, "Study on enhancement of Ultra-Reliable Low-Latency Communication (URLLC) support in the 5G Core network (5GC)", 2019, . Authors' Addresses Chathura Sarathchandra InterDigital Europe, Ltd. 64 Great Eastern Street, 1st Floor London EC2A 3QR United Kingdom Email: chathura.sarathchandra@interdigital.com Morteza Kheirkhah InterDigital Europe, Ltd. 64 Great Eastern Street, 1st Floor London EC2A 3QR United Kingdom Email: morteza.kheirkhah@interdigital.com Mona Ghassemian InterDigital Europe, Ltd. 64 Great Eastern Street, 1st Floor London EC2A 3QR United Kingdom Email: mona.ghassemian@interdigital.com Sarathchandra, et al. Expires January 13, 2022 [Page 12]