Tactile Internet Service Requirements

Document Type Active Internet-Draft (individual)
Authors Chathura Sarathchandra  , Morteza Kheirkhah  , Mona Ghassemian 
Last updated 2021-07-12
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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


   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

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   to this document.  Code Components extracted from this document must
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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

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   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",
   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.

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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

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   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

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   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

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.

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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

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

   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

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   their behaviour as the underlying network condition changes rapidly,
   mainly because the end-to-end measurements are implicit and thus

   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

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   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

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,

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   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,

              Muthusamy, Y. K. and C. Ullrich, "The 'haptics' Top-level
              Media Type", draft-muthusamy-dispatch-haptics-01 (work in
              progress), November 2020.

              ITU Network 2030 Technical Report, "Network 2030 - Gap
              analysis of Network 2030 new services, capabilities and
              use cases", 2020,

              Independent News Article, "SURGEON PERFORMS WORLD'S FIRST
              2019, <https://www.independent.co.uk/life-style/gadgets-

              ABmann, U. and et. al., "Human-robot cohabitation in
              industry", In  Tactile Internet, Academic Press pp. 41-73,

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              Aijaz, A. and et. al., "The Tactile Internet for
              Industries: A Review", In  Proceedings of the IEEE, 2019.

              Oppici, L. and et. al., "Internet of Skills", In  Tactile
              Internet, Academic Press pp. 75-99, 2021.

              ITU Network 2030 Technical Report, "Network 2030 - Gap
              analysis of Network 2030 new services, capabilities and
              use cases", 2020,

              ITU-T Technology Watch Report, "The Tactile Internet",
              2014, <https://www.itu.int/dms_pub/itu-t/oth/23/01/

              Ghassemian, M. and et. al., "Secure Non-Public Health
              Enterprise Networks", In  2020 IEEE International
              Conference on Communications Workshops (ICC Workshops),

              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, 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,

              Spiedel, S. and et. al., "Surgical Assistance and
              Training", In  Tactile Internet, Academic Press pp. 23-39,

              3GPP TR 22.847, "Study on supporting tactile and multi-
              modality communication services", 2021,

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              Aijaz, A. and et. al., "The Tactile Internet for
              Industries: A Review", In  Proceedings of the IEEE, 2019.

              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

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