M2M communication over cellular networks - VDE ITG

How to deal with a thousand nodes:

M2M communication over cellular networks

A. Maeder

NEC Laboratories Europe

[email protected]

ITG Zukunft der Netze 2011

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


The M2M use case landscape


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 (talk-

listen, download-reading, etc.)

But: M2M communication is different


Example: Smart Grid/Smart Metering

▐ Control and reading of metering/infrastructure

Smart Elec. Smart

Water

Appliances

Temperature

Light

Wind Turbine

Solar Panel

Smart

Gas

Meters Coms

Home displays

TV, Computer

In-Home

Energy

Display

Breaker Valves

Gateway

Data

Center

Wan

Communication

Image source: ETSI

Small message sizes

Low to medium frequent communication

Relaxed delay requirements

High requirements on energy efficiency?

Large number of devices

“Alarm” scenarios


Example scenario: smart meters per single cell

Estimation based on census data

One smart meter assumed per household


Example: Intelligent Transport Systems

Image source: ETSI

Very high

mobility/latency

requirements

High speed

mobility

Car-to-X:

High mobility

High speed

Very low latency

Security


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 Very high (up to

ten thousands

per cell)

Medium High low

Latency

requirements

low (up to hours) Medium

(seconds)

Very high (few

milliseconds)

Medium

(< 200ms)

Power

efficiency

requirements

High (battery

powered meters)

High (battery

power devices)

Low low

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!


Cellular M2M architecture

MME

HSS

P-GW

eNB

eNB

eNB

femto/small

cell

small cell

femto/small

cell

M2M platform

S-GW

Radio Access Network (RAN)

Mobile operator

core network

M2M operator

domain

Mobile operator

domain

management

operation

control

UE

UE

MTC

device

MTC

device MTC

device

M2M device

application M2M device

application

local

breakout

MTC server

abstraction

layer

M2M server

applications

data transport

addressing

locating

How to integrate?


Challenges for radio access

▐ Many devices

▐ Long idle intervals

▐ Small message transmission

▐ Uplink is bottleneck

▐ Energy efficiency

▐ Human communication must not be

affected!

eNB

UE eNB

Random Access Preamble1

Random Access Response 2

Scheduled Transmission3

Contention Resolution 4

Random access procedure in LTE for

attachment, uplink bandwidth requests RACH Congestion

▐ Proposed solutions:

▐ Dedicated RACH

▐ Time backoff classes

▐ Slotted access

▐ Group coordination

▐ Access barring

▐ Randomization


Challenges for non-access stratum

▐ 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

▐ Proposed solutions:

Signaling aggregation

Signaling rejection/differentiation

Signaling reduction for MTC device

classes

eNB

MME S/P-GW

HSS

S1-U S1-MME

S11

S6a

Signaling

congestion


Trade-off between control and scalability

Control Scalability

Security

Charging

QoS

Management

Monitoring

Scheduled access

Large device numbers

Low latency

Low power consumption

Small burst transmission

Low cost

Low overhead

Is it sufficient to modify existing technologies?

Diverse and partially contradicting requirements

Balancing mobile and M2M operator needs


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

▐ Interaction with MNO core

network functions (but not access)

M2M Area Network

M2M Applications

M2M Management

Functions M2M Service Capabilities

Core Network (CN)

Network Management

Functions

Access Network

Network Domain

M2M

Applications

M2MService

Capabilities

M2M Gateway

M2M Area

Network

M2M Device

M2M

Applications

M2M Service Capabilities

M2M Device

Device and Gateway

Domain


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 23.888

▐ Study on RAN improvements finished in Sept.

TR 37.868, section on RAN overload control

Extended Access Barring (EAB) selected as solution

3GPP bearer services / SMS / IMS

MTC Server

MTC Server

MTCi

MTCsms

3GPP PLMN - MTC Server IWK Function

MTCu MTC

Device

3GPP MTC architecture

Focus on

architecture/services

/signaling

Generic Service Layer API

MTC

Device

Service Logic

Components

HSSSM-

SCPGW

3GPP MTC

MTCshMTCiMTCsms

3GPP HPLMN

eNB, RNC or BSC

MTC

Device

MTCu

Service Abstraction Layer

MTC

Device

MTC User

MTC Server

. . .

3GPP VPLMN

PDN

3GPP MTC service abstraction


Activities in standards: IEEE 802.16p

▐ IEEE 802.16p: started in Sept. 2009

▐ Extension of 802.16e (WiMAX) and 802.16m (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

M2M

SubscriberM2M

Server

Connectivity

Service Network

Access Service

Network

IEEE 802.16

M2M device

IEEE 802.16

BS

MNO (Mobile Network Operator)

R1

IEEE 802.16

Non M2M

device

R1

IEEE 802.16

M2M device

Non IEEE

802.16

M2M device

R1

802.16p M2M service reference system architecture

Focus on air

interface/MAC


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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M2M communication over cellular networks - VDE ITG