Internet DRAFT - draft-sjkoh-requirements-iot-vlc
draft-sjkoh-requirements-iot-vlc
Network Working Group Seok J. Koh
Internet-Draft Cheol M. Kim
Intended status: Informational Kyungpook National University
Expires: 21 May 2021 17 November 2020
Requirements for IoT Services based on Visible Light Communications
draft-sjkoh-requirements-iot-vlc-01
Abstract
This document describes the requirements for IoT Services based on
Visible Light Communication (VLC) to effectively provide IoT services
in the VLC-based networks. This document includes the overview of
VLC technology and the concepts of VLC-based IoT services, and the
requirements for IoT services in the VLC-based networks.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology and Requirements Language . . . . . . . . . . 2
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Visible Light Communication . . . . . . . . . . . . . . . 3
2.2. IoT services based on VLC . . . . . . . . . . . . . . . . 4
2.3. Network nodes . . . . . . . . . . . . . . . . . . . . . . 6
2.3.1. IoT Server (IS) . . . . . . . . . . . . . . . . . . . 6
2.3.2. VLC Agent (VA) . . . . . . . . . . . . . . . . . . . 6
2.3.3. VLC Light (VL) . . . . . . . . . . . . . . . . . . . 6
2.3.4. User Terminal (UT) . . . . . . . . . . . . . . . . . 6
3. Requirements for IoT services based on VLC . . . . . . . . . 7
3.1. Device initialization . . . . . . . . . . . . . . . . . . 7
3.2. Device monitoring . . . . . . . . . . . . . . . . . . . . 7
3.3. Uplink channel for UT in the uni-directional VLC . . . . 7
3.4. Data transport . . . . . . . . . . . . . . . . . . . . . 8
3.5. Light control . . . . . . . . . . . . . . . . . . . . . . 8
3.6. Device roaming . . . . . . . . . . . . . . . . . . . . . 8
4. Security consideration . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. Normative References . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The VLC has been developed as a wireless communication technology
which uses visible lights, infrared (IR), and ultra-violet (UV)
spectrum instead of conventional RF band. In particular, the VLC
provides the following distinctive features: 1) non-interference to
existing RF bands, 2) free license to use the spectrum of visible
light, IR, and UV, and 3) VLC can be easily deployed with the
existing LED lights. Since the VLC is non-RF based wireless
communication technology, it can be complementary wireless
communication technology among the RF-based wireless communication
technologies (mobile network, WPAN, WLAN). These distinctive
features of VLC will be helpful to overcome the shortcomings of the
existing RF technologies.
1.1. Terminology and Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14. [RFC2119], [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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2. Overview
2.1. Visible Light Communication
The Visible Light Communication (VLC) technology has been developed
to transmit data through the license-free spectrum of visible light,
IR, and UV. [ITU-T_G.9991] [IEEE_802.15.7-2018] Data is encapsulated
into VLC frames, and it is coded using digital-based modulation
technology, such as Pulse Width Modulation (PWM), Orthogonal
Frequency Division Multiplexing (OFDM), and so on. Those coded VLC
frames are transmitted by LED or Laser Diode (LD). A Photo Diode
(PD) or an image sensor can receive the VLC frames.
The [ITU-T_G.9991] specifies the system architecture, PHY and data
link layer of high-speed indoor VLC transceiver, especially for home
network. The [ITU-T_G.9991] network comprises on or more domains.
Each domain has one domain master and one or more nodes which are
registered to the domain master. Global Master (GM) is responsible
to coordinate the resources among domains.
For each domain, the [ITU-T_G.9991] specifies the five topologies for
indoor VLC: peer to peer (or point to point) topology (P2P), point to
multipoint topology (P2MP), multipoint to multipoint (MP2MP), relayed
mode, and centralized topology. In addition to network topology, the
.[ITU-T_G.9991] specifies the modes of operation in a domain, which
includes centralized mode (CM) and unified mode (UM). In centralized
mode, the direct communication between domain master (DM) and end-
point node (EP) is allowed, while direct communication among end-
point nodes are note allowed. The CM supports 3 types of operation
mode: a) bi-directional communication, b) broadcast only, and c)
hybrid communication. In the unified mode, the direct or indirect
communication among nodes is allowed.
The [IEEE_802.15.7-2018] specifies PHY and MAC sublayer for VLC. In
[IEEE_802.15.7-2018], it uses the term Optical Wireless
Communications (OWC) rather than VLC because the standard explicitly
considers the wavelength from 10,000nm to 190nm, which includes
visible light, IR, and UV. Also, the standard introduces the term
Optical Wireless Personal Area Network (OWPAN) with specifying
network topology, addressing, collision avoidance, acknowledgement,
performance quality indication, dimming support, visibility support,
colored status indication, and color stabilization.
In [IEEE_802.15.7-2018], it classifies three types of devices in OWC:
infrastructure, mobile, and vehicle. Table 1 shows the
classification of devices.
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+-------------------+----------------+-------------+---------------+
| Features | Infrastructure | Mobile | Vehicle |
+===================+================+=============+===============+
| Fixed coordinator | Yes | No | No |
+-------------------+----------------+-------------+---------------+
| Power supply | Ample | Limited | Moderate |
+-------------------+----------------+-------------+---------------+
| Form factor | Unconstrained | Constrained | Unconstrained |
+-------------------+----------------+-------------+---------------+
| Light Source | Intense | Weak | Intense |
+-------------------+----------------+-------------+---------------+
| Physical mobility | No | Yes | Yes |
+-------------------+----------------+-------------+---------------+
| Range | Short/long | Short | Long |
+-------------------+----------------+-------------+---------------+
| Data rates | High/low | High | Low |
+-------------------+----------------+-------------+---------------+
Table 1: Device classification in [IEEE_802.15.7-2018]
The [IEEE_802.15.7-2018] specifies three network topologies: peer-to-
peer, star, and broadcast. A one device gets a role of coordinator,
which is determined by applications. The standard specifies the
visibility support across all topologies with flicker mitigation.
2.2. IoT services based on VLC
This document describes the concept of IoT services based on VLC.
The goal of VLC-based IoT services is the functionality as follows:
* Device initialization, including device discovery and device
registration.
* Data transport using VLC for downlink channel from lighting device
to user terminal.
* Data transport using VLC for uplink from user terminal to lighting
devices or using other RFs for uplink channel from user terminal
to the VLC agent device.
* Light control, such as the configuration of dimming, color,
modulation of visible lights.
* Device monitoring.
* Roaming support for mobile user terminal.
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Figure 2 and 3 shows the network model for VLC-based IoT services,
which uses bi-directional VLC environment and uni-directional VLC
environment. Also, those figures describe the network nodes in the
VLC-based IoT network: IoT server (IS), VLC Agent (VA), VLC Light
(VL), and User Terminal (UT).
+----+ Ethernet +----+ Ethernet/WLAN/WPAN +-----------+
| IS |<========>| VA |<==================>| VTs |
+----+ +----+ |(LED Light)|
+-----------+
* *
* Data *
* through VLC *
* (Visible light, *
* IR, UV) *
* *
^
+------------+ bi-directional VLC *
| UT | (VT <-> UT) *
|(IoT Device)|<*********************
+------------+
Figure 1: VLC-based IoT services in bi-directional VLC environment
+----+ Ethernet +----+ Ethernet/WLAN/WPAN +-----------+
| IS |<========>| VA |<==================>| VTs |
+----+ +----+ |(LED Light)|
## +-----------+
## * *
## Uplink channel * Data *
## for UT * through VLC *
## (WLAN/WPAN) * (Visible light, *
## * IR, UV) *
## * *
## *
+------------+ uni-directional VLC *
| UT | (downlink channel, VT -> UT) *
|(IoT Device)|<******************************
+------------+
Figure 2: VLC-based IoT services in uni-directional VLC environment
As shown in Figure 2 and 3, it is noted that there two kinds of VLC
between UT and VL/VA: uni-directional VLC and bi-directional VLC. In
the bi-directional VLC case, VLC is performed between UL and VL.
That is, both the downlink from VL to UT and the uplink from UT to VL
use the VLC. However, in the uni-directional VLC case, only the
downlink uses the VLC, whereas the uplink may use the other OF
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technologies, such as WLAN or WPAN. In the viewpoint of VLC
deployment in real-world networks, the bi-directional VLC is
suggested, but the uni-directional VLC may ne used in a certain
network.
For VLC-based IoT networks, we consider the following four types of
network nodes: Platform Server (PS), Aggregation Agent (AA), VLC
Transmitter (VT), and VLC Receiver (VR). Figure 1 shows uni-
directional VLC from VT to VR, in which only downlink VLC
transmission is allowed from VT to VR, and the uplink or backward
transmission will be made between VR and AA by using another network
link, such as WLAN or WPAN.
2.3. Network nodes
2.3.1. IoT Server (IS)
IS is responsible for overall management for all devices in VLC-based
IoT network. IS performs IP-based protocol operations including the
device initialization, device registration, device monitoring, light
control, and device roaming. In addition, IS transmits data to VL
and UT in the data transport operation. IS is connected to the
Internet.
2.3.2. VLC Agent (VA)
For effective management of VLC-based IoT services, one or more VAs
can be deployed in the network. VA is purposed to perform IP-based
protocol operations and to locally manage its associated VLs and UTs.
It keeps an association information between VL and UT, and such
information may be updated in the device monitoring and device
roaming operations. VA has a responsibility to relay data between IS
and VL/UT.
2.3.3. VLC Light (VL)
VL can be installed or embedded on an LED light. In the
initialization, VL is registered to IS. After that, VL advertises
itself to user terminals in the VLC network by using VLC. VL has a
responsibility to translate IP-based data to VLC frames and vice
versa.
2.3.4. User Terminal (UT)
UT represents a user device with the VLC functionality. All UTs can
be registered to and managed by IS via its associated VL and/or VA in
the device initialization and monitoring operations. VLC data are
also exchanged between UT and IS by way of VL and/or VA.
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3. Requirements for IoT services based on VLC
3.1. Device initialization
To enable IoT services based on VLC, all devices need to find uplink
device, join the network, and make them discoverable in the network.
The followings are the requirements for device initialization:
* All devices MUST have capabilities of device advertisement and
device discovery in VLC-based IoT network.
* Each device MUST generate its unique ID (Identifier) and make
association to its uplink device.
3.2. Device monitoring
IS manages all VA, VL, and UT in the network via monitoring
operations. The followings are the requirements for device
monitoring:
* Each device MUST generate its status information.
* Each device MUST send its status information to its uplink device
periodically.
* Each device MUST receive the request of status information from
its uplink device and MUST send its up-to-date status information
to the uplink device.
3.3. Uplink channel for UT in the uni-directional VLC
In uni-directional VLC environment, the UT, which only has capability
of downlink VLC, needs an uplink channel for enabling IoT services.
The followings are the requirements for uplink channel management:
* VA MUST create RF based uplink channel for uplink channel in the
uni-directional VLC case.
* VA MUST configure RF based uplink channel with the parameters
received from its uplink device.
* VA MUST send the information of RF based uplink channel to
downlink device.
* VA MUST forward data packets to uplink and downlink channel.
* VL MUST generate a VLC frame which includes the information of RF
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based uplink channel and to send the VLC frame to downlink device
periodically.
* UT MUST receive a VLC frame from uplink device and to extract the
information of RF based uplink channel.
* UT MUST establish the uplink channel with VA when UT has the uni-
directional VLC.
3.4. Data transport
In VLC-based IoT services, IP-based and VLC frame-based data need to
interoperate in all devices. The followings are the requirements for
data transport:
* All devices MUST handle IP-based data packets in VLC-based IoT
network.
* VL and UT MUST translate IP-based data packet to VLC frames, and
vice versa.
3.5. Light control
IS controls all VL by configuring the parameters associated with LED
lights. The followings are the requirements for light control:
* VL MUST handle the request of IS for configuration of LED light.
* VL MUST change the physical characteristics of LED light, as per
the request of IS.
3.6. Device roaming
When UT is mobile device, the IoT services need to be continued, even
though UT changes its attached VL. The followings are the
requirements for device roaming:
* UT MUST discover the neighboring VLs in the roaming case.
* UT MUST generate and exchange the roaming data with its
neighboring VL.
* VL MUST detect the roaming event from the association request with
the roaming data.
* VL MUST notify the roaming event to uplink VA device.
* IS and VL MUST handle the roaming request appropriately.
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4. Security consideration
TBD
5. IANA Considerations
TBD
6. Normative References
[IEEE_802.15.7-2018]
IEEE, "802.15.7-2018 - IEEE Standard for Local and
metropolitan area networks--Part 15.7: Short-Range Optical
Wireless Communications",
DOI 10.1109/IEEESTD.2019.8697198, 23 April 2019,
<https://ieeexplore.ieee.org/servlet/
opac?punumber=8697196>.
[ITU-T_G.9991]
International Telecommunications Union, "High-speed indoor
visible light communication transceiver - System
architecture, physical layer and data link layer
specification", ITU-T Recommendation G.9991, March 2019.
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Authors' Addresses
Seok-Joo Koh
Kyungpook National University
Daehakro 80, Bukgu, Daegu, South Korea 41566
Phone: +82 53 950 7356
Email: sjkoh@knu.ac.kr
Cheol-Min Kim
Kyungpook National University
Daehakro 80, Bukgu, Daegu, South Korea 41566
Email: cheolminkim@vanilet.pe.kr
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