INTAREA C. Sarathchandra
Internet-Draft M. Kheirkhah
Intended status: Informational M. Ghassemian
Expires: December 27, 2021 InterDigital Europe, Ltd.
Jun 25, 2021
Tactile Internet Service Requirements
draft-sarathchandra-tactile-internet-00
Abstract
The Tactile Internet refers to a new communication and networking
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 typical applications; 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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This Internet-Draft will expire on December 27, 2021.
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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. TI Service Requirements . . . . . . . . . . . . . . . . . . . 5
5.1. Haptic Media Type . . . . . . . . . . . . . . . . . . . . 5
5.2. Ultra-Low Latency . . . . . . . . . . . . . . . . . . . . 6
5.3. Ultra-High Reliability . . . . . . . . . . . . . . . . . 6
5.4. Coordination and Synchronization . . . . . . . . . . . . 6
5.5. Network-Application interaction . . . . . . . . . . . . . 7
5.6. Multi-Modal Parallel Transmission . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 8
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
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
service requirements partially (e.g., 5G URLLC [URLLC-3GPP]), a still
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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 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
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. 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.
5.1. 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
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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.
5.2. 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.
5.3. 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.
5.4. Coordination and Synchronization
The haptic applications often consist of multiple streams, e.g.,
audio, video, haptic, each co-stream with varying service
requirements (bitrates, 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 (e.g., for avoiding Cybersickness
[Promwongsa]). Therefore, mechanisms for the coordination and
synchronization of multiple flows, for both the same destination, and
for multiple destinations must be introduced.
A technical report published by ITU-T Focus Group on Technologies for
Network 2030 [ITU-NET2030] provides a gap analysis for supporting
Haptic and Tactile Communications in network 2030. Network 2030
services are defined as new network-layer services in the data plane,
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while haptic and tactile Network Services has been identified as one
of crucial services for the support of Network 2030. Moreover, in
addition to ultra-low latency, ultra-low packet loss and ultra-high
bandwidth requirements, mechanisms enabling coordination and
synchronization among co-flows has been highlighted as key service
requirements. Specifically, the authors highlight the lack of
carrying of information related to co-flow dependency and the
mechanisms for actively performing coordination by IP multicast set
of protocols. Due to the lack of information related to inter-
dependency among co-flows the data arrives at different receivers
without synchronization. Most TI applications involve interactive
bi-directional (in some cases real-time) communication. The authors
highlight that adapting to dynamic changes inside the network is
crucial and thus, having both state and co-dependency of flows
carried with the packet instead of maintaining them in the routers.
5.5. Network-Application interaction
Emerging TI applications are highly diverse in terms of their service
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 service
requirements; 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 is 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 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 needs to be realized. This way, applications and networks
can express their desired service requirements to one another,
permitting applications to adapt themselves to network constraints
and the networks to orchestrate their resource distribution according
to the applications' requirements. This is particularly essential
for TI applications which have highly diverse and often conflicting
service requirements.
5.6. Multi-Modal 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
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results in generation of multiple 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 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 parallel streams
of the same TI application. These mechanisms can significantly
benefit when there is an explicit feedback mechanism between TI
applications and networks (see Section Section 5.5 for more details).
6. IANA Considerations
This document requests no IANA actions.
7. 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].
8. 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,
for realizing the envisioned Tactile Internet, and for standardizing
relevant aspects such as protocols.
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9. Acknowledgments
The authors want to thank Renan Krishna for their very useful reviews
comments to the document.
10. References
10.1. 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>.
10.2. 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.
[IndustryTI]
Aijaz, A. and et. al., "The Tactile Internet for
Industries: A Review", In Proceedings of the IEEE, 2019.
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[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>.
[TIAijaz2019]
Aijaz, A. and et. al., "The Tactile Internet for
Industries: A Review", In Proceedings of the IEEE, 2019.
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[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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