Internet-Draft Seok J. Koh Intended status: Informational Cheol M. Kim Expires: 7 May 2020 Kyungpook National University 4 November 2019 Requirements for IoT Services based on Visible Light Communications draft-sjkoh-requirements-iot-vlc-00 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 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 7 May 2020. Copyright Notice Copyright (c) 2019 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 to this document. Koh & Kim Expires 7 May 2020 [Page 1] Internet-Draft Requirements for IoT Services based on VLC November 2019 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. Koh & Kim Expires 7 May 2020 [Page 2] Internet-Draft Requirements for IoT Services based on VLC November 2019 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. Koh & Kim Expires 7 May 2020 [Page 3] Internet-Draft Requirements for IoT Services based on VLC November 2019 +-------------------+----------------+-------------+---------------+ | 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. Koh & Kim Expires 7 May 2020 [Page 4] Internet-Draft Requirements for IoT Services based on VLC November 2019 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 Koh & Kim Expires 7 May 2020 [Page 5] Internet-Draft Requirements for IoT Services based on VLC November 2019 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. Koh & Kim Expires 7 May 2020 [Page 6] Internet-Draft Requirements for IoT Services based on VLC November 2019 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 Koh & Kim Expires 7 May 2020 [Page 7] Internet-Draft Requirements for IoT Services based on VLC November 2019 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. Koh & Kim Expires 7 May 2020 [Page 8] Internet-Draft Requirements for IoT Services based on VLC November 2019 4. Security consideration TBD 5. IANA Considerations TBD 6. 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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [ITU-T_G.9991] International Telecommunications Union, "High-speed indoor visible light communication transceiver - System architecture, physical layer and data link layer specification", March 2019. [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", 23 April 2019, . 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 Koh & Kim Expires 7 May 2020 [Page 9]