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
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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",
"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.
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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
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.
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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
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
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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
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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
[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,
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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,
<https://www.rfc-editor.org/info/rfc2119>.
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,
<https://ieeexplore.ieee.org/document/8605315>.
[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,
<https://www.itu.int/pub/T-FG-NET2030-2020-1>.
[Independent]
Independent News Article, "SURGEON PERFORMS WORLD'S FIRST
REMOTE OPERATION USING '5G SURGERY' ON ANIMAL IN CHINA",
2019, <https://www.independent.co.uk/life-style/gadgets-
and-tech/news/5g-surgery-china-robotic-operation-
a8732861.html>.
[IndustryRobot]
ABmann, U. and et. al., "Human-robot cohabitation in
industry", In Tactile Internet, Academic Press pp. 41-73,
2021.
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[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,
<https://www.itu.int/pub/T-FG-NET2030-2020-1>.
[ITU-T2014]
ITU-T Technology Watch Report, "The Tactile Internet",
2014, <https://www.itu.int/dms_pub/itu-t/oth/23/01/
T23010000230001PDFE.pdf>.
[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,
<https://ieeexplore.ieee.org/document/8542940>.
[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,
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3848>.
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[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,
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3453>.
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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