m2m communication over cellular networks - vde itg
TRANSCRIPT
How to deal with a thousand nodes:
M2M communication over cellular networks
A. Maeder
NEC Laboratories Europe
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
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
Example scenario: smart meters per single cell
Estimation based on census data
One smart meter assumed per household
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
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!
ITG Zukunft der Netze 2011
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?
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
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
ITG Zukunft der Netze 2011
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.