2014. 05.28

윤 주 상 (동의대학교)

jsyoun@deu.ac.kr

IoT를 위한 Connectivity 기술 동향

“IoT - Beyond Connectivity” 워크샵

Contents

• IoT Connectivity 소개

• Machine Type Communication(MTC) in 3GPP

• D2D 직접 통신 기술

- 3GPP Proximity Service(ProSe)

- WiFi P2P

• Conclusion

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IoT World

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Source: http://advisoranalyst.com/glablog/wp-content/uploads/2013/11/ISF_Infographic_1600x944.jpg

IoT Connectivity

• IoT 환경

- RFID/USN/NFC/M2M 기술로 IoT physical thing(device, machine) & virtual thing(information)을 인터넷 통해 또는 thing 간 연결

- RFID/USN/NFC와 IoT/M2M 비교

- IoT connectivity

• Infra/Infra-less based D2D communication

• M2M, D2D in mobile network(3GPP), D2D by WiFi

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RFID/USN/NFC M2M IoT

통신방식 (connectivity)

근거리망 기반 근거리통신망, 이동통신망을 통한 인터넷 연

결

인터넷중심,

디바이스 중심

디바이스 형태

센서중심 장치중심 센서, 액츄에이터, 가

상 Thing(IoT)

디바이스 역활

/서비스 단순 정보 수집

정보 수집 & 서비스 제공

지능적 판단

규모 수천만개의 사물 수백억이상 사물

Internet based IoT Connectivity

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D2D 직접 통신 기반 서비스 소개

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Machine Type Communication(MTC) in 3GPP

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MTC in 3GPP

• Architecture enhancements to facilitate communications with packet data networks and applications (3GPP SA2 TR 23.682v12.1.0)

- Scope

• The network elements, interfaces and procedures as per the use cases and service requirements defined in TS 22.368

• Study on Machine-Type Communications (MTC) and other mobile data applications communications enhancements(3GPP TR 23.887V12.0.0)

- Scope

• Architectural enhancements for Machine-Type and other mobile data applications Communications

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Architectural Reference Model

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Reference Point Requirements

• Reference Point

- Tsp, T4, T5a/b/c, S6m/n

• High Level Function

- Device Triggering Function

- PS-only Service Provision

- Core Network assisted RAN parameters tuning

- UE Power Saving Mode

• Identifier

- External Identifier = <Local-Identifier> <MNO-Identifier>

• The 2-tuple (local-identifier, MNO-Identifier) becomes globally unique

• Example Formats:

- As NAI: local-identifier@mno-domain-name

• Addressing

- IPv6 for MTC

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Network Elements

• Network Elements

- MTC-IWF

• Ability to authorize the SCS before communication establishment with the 3GPP network

• Ability to authorize control plane requests from an SCS

• Support device trigger functionality

- Request, acceptance, report

- Map E.164 MSISDN or External Identifier to IMS

• Selection of the most efficient and effective device trigger delivery mechanism

- MTC AAA

• Return the external identifier(s) corresponding to an IMSI

• Replace IMSI with an External Identifier for messages to an external AAA server

• Identifying the destination external AAA server

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In TR 23.887

• Solutions for Key Issue in TS 22.368

- Small Data transmission

• Small Data transmission scheme

• Efficient handling of frequent small data transmission

- Device Triggering Enhancements

• Device triggering enhancements including T5 based device trigger and other triggering efficiency optimizations

- Monitoring Enhancements

- Power Consumption Optimizations

• Optimizations to prevent battery drain (that may come from e.g. frequent changes between Idle and Connected mode or too long periods in connected mode);

- Group Based Feature (GROUP)

• The group based policing requirements/addressing requirements/charging requirements

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D2D 직접 통신 기술

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D2D Communication

• Device to Device Direct Communication

- 기지국(Base Station, AP)과 같은 infrastructure 없이 인접한 장치 사이에 모바일 트래픽을 직접 전달하는 분산형 통신 기술

• 현재 D2D 기술은 IoT 서비스 관점에서 IoT 서비스 제공을 위한 기술로 진화 중

• D2D Communication Procedure

- Device discovery

• D2D 통신 환경에서 각 노드는 스스로 물리적으로 인접한 장치을 탐색

- D2D communication session

• 인접한 장치와 트래픽 전송을 위한 직접 통신 세션을 설정

- Data transmission over communication session

• 현재는 D2D 통신 기반의 Service Discovery 에 초점을 맞추고 있음

- Service Discovery

• Discover available higher-layer services = IoT connectivity

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ProSe(Proximity Service) in 3GPP

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Proximity Services Scenario

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Disaster Scenarios

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ProSe in 3GPP

• Feasibility Study for Proximity Services (ProSe)

- 3GPP SA1 TR 22.803v12.2

- Scope

• Use Cases and Scenarios

• Requirements

• Study on architecture enhancements to support Proximity-based Services (ProSe)

- 3GPP SA2 TR 22.703v12.0.0

- Scope

• Assumptions and architectural requirements

• Key Issues/Solutions

• Proximity criteria can be different for discovery and communication

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Definitions

• Proximity Service/Discovery

- A process that identifies that a UE is in proximity of another, using E-UTRA or EPC

• ProSe Communication

- A communication between two UEs in proximity

- The communication path could be established directly between the UEs or routed via local eNB(s)

- The ProSe Communication path

• Direct communication between the UEs

• Or routed via the local eNB

• Service model

- Commercial model

- Public Safety model

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Use Cases

• Diverse service requirement

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Topology Scenarios - Pure D2D Architecture

• Localized data Service

- M2M (V2V)

- Content sharing

- Multi-user gaming

- Mobile advertising

- Local voice service

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Data flow

Control flow

Topology Scenarios - D2D Multicast Architecture

• Localized data Service

- Content sharing

- Multi-user gaming

- Mobile advertising

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Data flow

Control flow

Topology Scenarios - D2D Relaying Architecture

• Localized data Service

- Relay-functionality

- Sensor networks

• UE as gateway to sensors

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Data flow

Control flow

Case A: UE-to-Network relay or UE-to-UE relay

Case B: UE-to-UE relay

Ran Support & Frequency Bands

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D2D Discovery & Communication(1/2)

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D2D Discovery & Communication(2/2)

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Direct Discovery Model

• Model A ("I am here”)

- This model defines two roles for the UEs that are participating in direct discovery

• Announcing UE

- The UE announces certain information that could be used from UEs in proximity that have permission to discover.

• Monitoring UE

- The UE that receives certain information that is interested in from other UEs in proximity

• Model B ("who is there"/"are you there")

- This model defines two roles for the UEs that are participating in direct discovery.

• Discoverer UE

- The UE transmits a request containing certain information about what is interested to discover

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Reference Architecture Model

• Reference Points

- PC1 ~ 8

- PC2: application data updates for a ProSe database

- PC3: configuration for ProSe discovery and communication

- PC4: setting up a communication path for D2D

- PC5: control and user plane for discovery and communication

• ProSe function: EPC level ProSe discovery, handling of ProSe identities, Security, charging, Authorization

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Technology Requirements for D2D

• For D2D, UE should to able to

- Discover other UEs

- Measure the channel from other UEs

• The measurement result needs be reported to other UEs or to eNB

- Receive signal via UL resource

• It is expected that D2D communication will take place in UL resource

- Maintain two different links

• One link with BS, another one with other UE(s)

• For D2D, eNB should be able to

- Control D2D links

• Scheduling individual D2D transmission (tight) or high level control (loose)

- Do interference coordination

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Challenges

• Challenges for efficient D2D Discovery

- Discovery signals might collide

- UE cannot listen to others while it is transmitting

• Challenges for D2D Communication

- if UE controlled

• Collisions problem, critical for latency-sensitive D2D service & local sub-optimal due to the lack of NW support

- If NW controlled

• Spatial re-use not possible (e.g. w/o GPS info.); high RRC signaling overhead; not applicable out of NW coverage

- D2D between devices subscribed to different operators

- How to monitor direct communication?

- Privacy, Security, Authentication

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WiFi Direct

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Wi-Fi Direct Overview

• Overview

- Connects devices directly, with or without a Wi-Fi network or hotspot available

• Applications

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Transfer files

• Connecting is easy

- Wi-Fi Direct devices discover one another and in some cases

• Connections are protected by WPA2™ security

• Connect two or more devices

Ad-hoc Mode/Wi-Fi Direct

• Wi-Fi Direct technology as described in “Wi-Fi Peer-to-Peer (P2P) Technical Specification”

- Instead of leveraging the ad-hoc mode of operation

• Wi-Fi Direct builds upon the successful IEEE 802.11 infrastructure mode

- Lets devices who will take over the AP-like functionalities

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Ad-hoc mode Wi-Fi Direct

- No central infrastructure

- Flat architecture

- Offer minimal security

- Maximum of 11 Mbps bandwidth

- Infrastructure-like network

- Negotiate the roles of AP

- Support WPS (Wi-Fi Protected Setup)

- Maximum bandwidth of Wi-Fi

P2P Architecture

• P2P components

- P2P Device: Supports both P2P Group Owner and P2P Client roles.

- P2P Group Owner(GO) role: “AP-like” entity

- P2P Client role: non-AP STA functionality

• P2P Topology

1:1 P2P Group

P2P Group Owner

P2P Client

1:n P2P Group

P2P Group Owner

P2P Client

Legacy Client

WLAN-STA

P2P Device

P2P Device

AP

WLAN BSS P2P Group

P2P Concurrent Device

P2P Specific Functions & Services

• A P2P device supports following P2P specific functions:

- P2P Discovery

• Provides a set of functions to allow a device to easily and quickly identify and connect to another P2P Device and its services in its vicinity

- P2P Group Operation

• Resembles infrastructure BSS operation as defined in IEEE Std 802.11-2007

- P2P Power Management

• Provides a set of functions to reduce power consumption of P2P Devices

- Managed P2P Device (optional)

• Describes the ability for P2P Devices to operate in an enterprise environment where P2P Devices may be managed by the Information Technology (IT) department of the enterprise

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P2P Discovery

• P2P Discovery enables P2P Devices to quickly find each other and form a connection

• Major components:

- Device Discovery

• facilitates two P2P Devices arriving on a common channel and exchanging device information (e.g. device name and device type)

- Service Discovery (optional)

• a P2P Device to discover available higher-layer services prior to forming a connection

- Group Formation

• is used to determine which device will be the P2P Group Owner and form a new P2P Group

- P2P Invitation

• is used to invoke a Persistent P2P Group or invite a 14 Device to join an existing P2P Group

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Example Device Discovery procedures for a P2P Device

Group Formation

• Group Formation procedure involves two phases

- Determination of P2P Group owner

• Negotiated - Two P2P devices negotiate for P2P group owner based on desire/capabilities to be a P2P GO

• Selected - P2P group Owner role established at formation or at an application level

- Provisioning of P2P Group

• Establishment of P2P group session using appropriate credentials

• Using Wi-Fi simple configuration to exchange credentials

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Wi-Fi Direct GO Negotiation and Group Formation Sequence

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Conclusions

• IoT Connectivity Research

- Constraint Node Network in IETF

- MTC/M2M Network/D2D Communication in 3GPP

- WiFi P2P

• IoT: 50 billion things(?) connected

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