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TRANSCRIPT
2014. 05.28
윤 주 상 (동의대학교)
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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4
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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