How to deal with a thousand nodes: M2M communication over cellular networks. A. Maeder NEC Laboratories Europe andreas.maeder@neclab.

Transcription

1 How to deal with a thousand nodes: M2M communication over cellular networks A. Maeder NEC Laboratories Europe andreas.maeder@neclab.eu

2 Outline Introduction to M2M communications The M2M use case landscape Properties and requirements Challenges for mobile cellular networks Architecture Challenges on RAN and core network Current efforts in standardization ETSI: end-to-end framework for M2M 3GPP: Keep the operators into the value chain IEEE: Optimize the radio access Conclusion and outlook

3 The M2M use case landscape

4 What is the issue? Cellular mobile networks are designed for human communication Interactive communication between humans (voice, video) Data communication involving humans (web browsing, file downloads, etc). Communication is connection-centric Cellular mobile networks are optimized for traffic characteristics of human-based communication applications Communication with a certain length (sessions) and data volume Communication with a certain interaction frequency and patterns (talklisten, download-reading, etc.) But: M2M communication is different

5 Example: Smart Grid/Smart Metering Control and reading of metering/infrastructure Wind Turbine Solar Panel Light Home displays TV, Computer In-Home Energy Display Wan Communication Data Center Appliances Meters Coms Temperature Breaker Valves Smart Water Smart Gas Smart Elec. Small message sizes Low to medium frequent communication Relaxed delay requirements High requirements on energy efficiency? Large number of devices Alarm scenarios Gateway Image source: ETSI

6 Example scenario: smart meters per single cell Estimation based on census data One smart meter assumed per household

7 Example: Intelligent Transport Systems High speed mobility Very high mobility/latency requirements Car-to-X: High mobility High speed Very low latency Security Image source: ETSI

8 Properties and requirements of M2M applications Smart meters ehealth ITS Surveillance Mobility none Pedestrian /vehicular Vehicular none Message size Small (few kb) Medium? Medium large Traffic pattern Regular Regular/irregular Regular/irregular Regular Device density Latency requirements Power efficiency requirements Very high (up to ten thousands per cell) low (up to hours) High (battery powered meters) Medium High low Medium (seconds) High (battery power devices) Very high (few milliseconds) Low Medium (< 200ms) Reliability High High High medium Security requirements High Very high Very high medium Diverse and challenging requirements for today s mobile networks Requirements and traffic patterns are not clear today! low

9 Cellular M2M architecture Mobile operator domain M2M operator domain HSS M2M server applications MME S-GW P-GW MTC server abstraction layer M2M platform Mobile operator core network Radio Access Network (RAN) local How breakout to integrate? management operation control MTC device femto/small cell enb UE UE enb femto/small cell MTC device enb small cell MTC device data transport addressing locating M2M device application M2M device application

10 Challenges for radio access Many devices Long idle intervals Small message transmission Uplink is bottleneck Energy efficiency Human communication must not be affected! 1 3 UE enb Random Access Preamble Random Access Response 2 Scheduled Transmission Contention Resolution 4 RACH Congestion Random access procedure in LTE for attachment, uplink bandwidth requests enb Proposed solutions: Dedicated RACH Time backoff classes Slotted access Group coordination Access barring Randomization

11 Challenges for non-access stratum HSS S6a MME S1-MME Signaling congestion S11 S/P-GW S1-U Each data transmission from idle mode requires a bearer setup Complex procedure with several CN entities involved Large overhead for small message sizes May lead to signaling congestion and high computational load enb Proposed solutions: Signaling aggregation Signaling rejection/differentiation Signaling reduction for MTC device classes

12 Trade-off between control and scalability Security Charging QoS Management Monitoring Scheduled access Large device numbers Low latency Low power consumption Small burst transmission Low cost Low overhead Control Scalability Diverse and partially contradicting requirements Balancing mobile and M2M operator needs Is it sufficient to modify existing technologies?

13 Activities in standards: ETSI ETSI develops an end-to-end framework for M2M Architecture highlights Generic service capabilities for M2M applications in M2M server, gateway and devices M2M identification and addressing scheme Framework for security and service bootstrap Resource management framework Independent of transport network Network Domain Device and Gateway Domain Interaction with MNO core network functions (but not access) M2M Area Network M2M Applications M2M Service Capabilities M2M Applications M2MService Capabilities M2M Gateway M2M Device Core Network (CN) Access Network M2M Applications M2M Service Capabilities M2M Device M2M Management Functions Network Management Functions

14 Activities in standards: 3GPP Two work items: network improvements for MTC (NIMTC, Rel. 10) and system improvements for MTC (SIMTC, Rel. 11) Current focus on architecture (MTC server), control plane, services, features: TR Study on RAN improvements finished in Sept. TR , section on RAN overload control Extended Access Barring (EAB) selected as solution MTC User Service Logic Components Generic Service Layer API MTC Server PDN Focus on architecture/services /signaling 3GPP MTC Service Abstraction Layer MTCsms MTCi MTCsh MTC Device MTCu 3GPP bearer services / SMS / IMS 3GPP MTC architecture MTCsms MTCi 3GPP PLMN - MTC Server IWK Function MTC Server MTC Server SM- SC PGW... 3GPP HPLMN enb, RNC or BSC MTCu MTC Device HSS 3GPP VPLMN 3GPP MTC service abstraction

15 Activities in standards: IEEE p IEEE p: started in Sept Extension of e (WiMAX) and m (WiMAX 2.0) MAC and minimal OFDMA PHY enhancements Current status: enhancements for network entry, group control, multicast, mobility, dedicated random access resources Letter ballot in Nov. 2011, publish 2012 MNO (Mobile Network Operator) Focus on air interface/mac IEEE Non M2M device R1 Access Service Network Connectivity Service Network M2M Server M2M Subscriber IEEE M2M device R1 IEEE BS Non IEEE M2M device IEEE M2M device R p M2M service reference system architecture

16 Conclusion and Outlook M2M is an enabler of the Internet of Things. M2M is challenging for today s and future cellular networks: Interworking between M2M operator and mobile operator. Diverse traffic characteristics and requirements on QoS, energy efficiency, Efforts in Standards: Fix existing systems by adding as much as necessary, as less as possible. Research needs to think beyond this approach M2M applications imply novel network performance metrics Flexible MAC, low-overhead protocols, virtualization, energy efficiency, hierarchical networks, First step: M2M traffic models for popular use cases (e.g. smart meters)! Talk to industries and users of M2M communications.

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