Presentation 210 antoinette verdone mobile devices-access and use for pals_handouts
Shaping mobile networks for the IoT - Roberto Verdone direction Bi-directional Mainly uplink ... •...
-
Upload
nguyenkhue -
Category
Documents
-
view
215 -
download
1
Transcript of Shaping mobile networks for the IoT - Roberto Verdone direction Bi-directional Mainly uplink ... •...
Slide subtitle
Massimo CondoluciResearch Associate
Department of InformaticsCentre for Telecommunications Research
King’s College London
Shaping mobile networks for the IoT
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 20172
CTR @KCL
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 20173
CTR @KCL
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 20174
• Introduction to IoT and LPWA technologies
• Introduction to mobile networks
• Cellular IoT
• The IoT in the mobile core network
Outline
Slide subtitle
Massimo CondoluciResearch Associate
Department of InformaticsCentre for Telecommunications Research
King’s College London
Shaping mobile networks for the IoT
Introduction to IoT andLow Power Wide Area
(LPWA) Networks
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 20176
Internet of Things
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 20177
Internet of Things
https://www.ericsson.com/en/networks/topics/iot-connectivity/iot-use-cases-and-requirements-on-technology
Orange and Ericsson, “Traffic Model for legacy GPRS MTC; document GP 160060.” 3GPP GERAN meeting #69, Feb 2016.
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 20178
Machine-type communications
https://www.ericsson.com/en/networks/topics/iot-connectivity/iot-use-cases-and-requirements-on-technology
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 20179
Internet of Things
ZonePop. Density per
SqKm
Pop. Density per
Household
Household
density per sqKm
Cell Radius
Km
Household per
cell
MTC Devices
Per Household
Central 1E4 1.58 6329 0.54968
(4114)40
Urban 7.5E3 2.64 2840 235670
(29508)40
ZoneMTC Devices Per
Cell
Smartphones
per Cell
Central198720
(164560)6500
Urban1426800
(1180320)77925
Zone
MTC
Devices Per
Cell
(no Mob.)
Device Triggered Network Triggered
Reporting Time T
(Sync – Unif. Over T)
(Async – Beta Over T)
Packet Size
(UL)
Reporting Time T
(Sync – Unif. Over T)
(Async – Beta Over T)
Packet Size
(DL/UL)
Central 164560 1m, 5m, 1h, 12h, 24h 1000, 10000 1m, 5m, 1h, 12h, 24h 1000,10000/400
Urban 1180320 1m, 5m, 1h, 12h, 24h 1000, 10000 1m, 5m, 1h, 12h, 24h 1000,10000/400
3GPP TR 37.868 Annex B and TR 45.820 Annex E
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201710
Internet of Things
https://www.ericsson.com/en/networks/topics/iot-connectivity/iot-use-cases-and-requirements-on-technology
Orange and Ericsson, “Traffic Model for legacy GPRS MTC; document GP 160060.” 3GPP GERAN meeting #69, Feb 2016.
• Total density: 32600 device/sqkm
• Total traffic: ~35000 device/hour = ~10 pkts/s
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201711
Machine-type communications
Human-type traffic Machine-type traffic
Traffic direction Bi-directional Mainly uplink
Message size Large/Very Large Small
Traffic duration From 10s of seconds to minutes Very short (one transmission)
Delay Variable Usually delay-tolerant
Transmission periodicity No period, frequent sessions From 10s of minutes to hours
Mobility From static to high-mobility Static, very low
Information priority Usually low From low to high
Amount of devices 100s per cell 1000s per cell (target ~35000)
Battery lifetimeRe-charge whenever a socket is
available!In the order of years
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201712
• Objectives
• Battery duration ~10 years
• Optimized for the transmission of brief messages
• Low module cost (<5$)
• Coverage in the order of 10s of km for a cell
• Outdoor, indoor, deep-indoor, underground coverage
• High link budget with narrowband modulation
• “Short” time-to-market
• Support very huge number of devices (massive MTC - mMTC)
• End-to-end secure connectivity (application authentication)
Low Power Wide Area (LPWA)
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201713
LPWA vs Other Techonologies
https://ioncomm.blogspot.com/2016/10/lpwa-low-power-wide-area-core-of-iot.html
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201714
Low Power Wide Area (LPWA)
LPWA
Technologies
ISM Band Licensed spectrum
3GPP LTE Cat.0
3GPP: Rel. 12
LTE-M
NB-IOT
LoRa
SigFox
RPMA
IngenuWeightless
EC-GSM-IoT
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201715
LPWA vs other technologies
http://www.theiet.org/sectors/information-communications/topics/ubiquitous-computing/articles/lpwan.cfm
Billion global connection covered by different wireless networks 2015-2025 (Machina Research, May 2015)
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201716
• Ultra Narrowband Modulation (200 kHz)
• Each message is 100 Hz, and transferred at
100/600 bps
• UL message
• Up to 12-bytes payload and takes an average
2s
• For a 12-byte data payload, a Sigfox frame will
use 26 bytes in total
• Max 140 msg/day per device
• DL message
• The payload allowance in downlink messages is
8 bytes
• Max 4 msg/day per device
• Star network architecture
• The broadcasted message is received by any
base station in the range, (3 on average)
SigFox
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201717
• Based on Chirp Spreading Spectrum (CSS)
• Exploitation of multiple gateway
• The network replies through the best gateway
• Three classes of devices
• Class A
• The device has two DL windows after a UL transmission
• Class B
• The device gets extra DL windows in addition to those of class A
• Class C
• The device can always receive in DL
LoRA
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201718
• The idea is to provide connectivity to IoT devices via cellular networks
• Ad-hoc radio interfaces tailored for IoT requirements
• Exploitation of the same physical layer technique as current cellular
technologies, to guarantee a deployment via a software update of currently
deployed base stations
• Re-utilization of the core network
• Take advantage of the already available cellular coverage
• EC-GSM-IoT
• Enhancement of EGPRS
• LTE-M
• Enhancement of LTE with extended power saving modes
• NB-IoT
• New radio added tailored for low-end market
Cellular IoT
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201719
LPWA scenario
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201720
LPWA comparison
U. Raza, P. Kulkarni and M. Sooriyabandara, "Low Power Wide Area Networks: An Overview," in IEEE Communications Surveys & Tutorials, vol.
19, no. 2, pp. 855-873, Secondquarter 2017.
H. Wang and A. O. Fapojuwo, "A Survey of Enabling Technologies of Low Power and Long Range Machine-to-Machine Communications," in IEEE
Communications Surveys & Tutorials, vol. PP, no. 99, pp. 1-1.
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201721
LPWA comparison
https://www.slideshare.net/RobertVivancoSalcedo/understand-lpwa-tetchnologies-sigfox-and-lora
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201722
LPWA comparison
U. Raza, P. Kulkarni and M. Sooriyabandara, "Low Power Wide Area Networks: An Overview," in IEEE Communications Surveys & Tutorials, vol.
19, no. 2, pp. 855-873, Secondquarter 2017.
H. Wang and A. O. Fapojuwo, "A Survey of Enabling Technologies of Low Power and Long Range Machine-to-Machine Communications," in IEEE
Communications Surveys & Tutorials, vol. PP, no. 99, pp. 1-1.
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201723
LPWA comparison
U. Raza, P. Kulkarni and M. Sooriyabandara, "Low Power Wide Area Networks: An Overview," in IEEE Communications Surveys & Tutorials, vol.
19, no. 2, pp. 855-873, Secondquarter 2017.
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201724
• Cost of cellular IoT
• LTE-M and NB-IoT are software-updates of existing LTE cells
• “In theory” the cost should be low(er than LoRA)
• In practice, the cost of deploying cellular IoT is not clear yet
• Cost of the SLA
• SLA means somehow radio/core networks reservation/guarantee
• Currently, business models are mainly based on amount or speed
• Pay-as-you-go, periodic allowance, up to 20Mbps, etc.
• Amount/speed charging might mean high cost for cellular IoT
• Huge number of devices generating very small data traffic means many resources
(control-plane traffic) to be used to control such devices
• Control-plane traffic does not generate revenue for the operator
Change of business model (?)
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201725
• The IoT is becoming… real!
• The IoT has a wide set of use cases
• Precise information about density of devices, location of devices (indoor, deep
indoor, underground), traffic models, etc. still not available
• The IoT has unique features in terms of traffic and device requirements, thus
requiring ad-hoc technologies
• As well as it is not efficient to support human-type and machine-type traffic
types with the same technology, it is not efficient to support different use cases
of the IoT with the same technology
• Supporting the IoT via mobile networks is definitely interesting for operators, it
may be interesting for customers depending to the business models adopted by
the operators
• Cellular IoT technologies are more flexible compared to others, and their
integration within 3GPP standards means efforts in guaranteeing future
backward-compatible evolutions
Remarks
Slide subtitle
Massimo CondoluciResearch Associate
Department of InformaticsCentre for Telecommunications Research
King’s College London
Shaping mobile networks for the IoT
Introduction to mobile networks
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201727
IoT via cellular networks
E-UTRAN
Evolved Packet
Core (EPC)
MTC Server
Evolved Packet
System (EPS)
User
Equipments
(UEs)
BS/eNB
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201728
• The Radio Access Network (RAN) has the role of:
• Connecting the UE to the CN
• Offering wireless resources to the UE to transfer/receive UP traffic
• Managing the spectrum
• Providing the UE with network information (e.g., broadcast information) to allow a UE
to trigger a connection request
Radio Access Network (RAN)
• Connection means:
• The UE is authenticated and authorized
• The UE will have “resources” for its data transfer
eNB
System Information
CNUE
Attachment: Authentication & Authorization
Connection request
Connection establishment
Data transfer
~200 ms
in case of
auth.
~35ms
without
auth.
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201729
States
https://https://www.slideshare.net/HussienMahmoud2/lte-epc-technology-essentials
• (EMM) EPS Mobility Management
• (ECM) EPS Connection Management
• (TRAU) Tracking Area Update
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201730
• Based on OFDM
• OFDMA for downlink and SC-FDMA for uplink
• Flexible bandwidth from 1.4 to 20 MHz (i.e., from 6 to 100 resource blocks -
RBs)
• High efficiency in terms of spectrum management
Long Term Evolution
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201731
• (PRACH) Physical Random Access Channel
• (PUSCH) Physical Uplink Shared Channel
• (PUCCH) Physical Uplink Control Channel
UL channels in LTE
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201732
• (PUSCH) Physical Uplink Shared Channel
• Carry UP data
• RBs of the PUSCH are assigned by the BS to the UE
• The UE performs a scheduling request procedure transmitting the buffet state
report (BSR)
• The BS allocates the RBs (UL grant)
• Support power control
• (PRACH) Physical Random Access Channel
• Composed of 6RBs
• Preambles (pseudo-orthogonal resources) are sent on the PRACH
• PRACH is a periodic channel (PRACH periodicity can be varied, usually 5ms)
• Used to perform the random access (RA) procedure
• Performed by a UE if it is in idle state to switch in connected mode
• MTC devices are usually in idle, thus need to switch to connected mode
before transmitting
• The RA is the key procedure in the RAN for MTC traffic
UL channels in LTE
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201733
Random access (RA) procedure
4-way handshake procedure
1. Preamble transmission. Synchronization
acquisition to inform the base station (BS)
on the incoming request.
2. Random Access Response (RAR). The BS
sends the uplink (UL) grant for the
connection request.
3. Connection Request. The UE sends the
effective connection request.
4. Connection resolution. The BS informs the
UE about the accomplishment of the
connection establishment
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201734
Random access (RA) procedure
An eye into the RA:
• 64 preambles are defined by the network
• 54 preambles are reserved for contention-based RA
• When UEs wake up (i.e., the MTC application generates a packet to be transmitted),
they wait for the first available RA opportunity to send a randomly chosen preamble
• If two or more UEs select the same preamble, a collision may occur
• Collision means that the colliding UEs have to perform a new RA attempt
• 54 preambles every 5ms means that the maximum PRACH has 10800 preamble/s
• In a ideal scenario without collisions, the PRACH can support 10800 UE/s
• Practically, collisions limit the capacity of PRACH
• A collision occurs if two or more devices select the same preamble in the same RA
opportunity
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201735
Random access (RA) procedure
Idle Transmission Reception
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201736
Random access (RA) procedure
• A collision occurs if two or more devices select the same preamble in the same
RA opportunity
• 1000 UEs transmitting in 1s brings to 5 device per RA opportunity (RA
periodicity 5ms) with a collision probability lower than 10%
• Capacity is an issue for the RA procedure only when considering scenarios
with event-correlated transmissions
• A fire alarm has been reported and 1000s of devices perform the RA
simultaneously (or in a very short period of time)
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201737
• Pros
• High data rates (reaching 100s Mbps with LTE-Advanced)
• “Low” latency (8ms to complete a HARQ process)
• Somehow future-proof (“easy” process to switch from LTE to LTE-A)
• “Enough capacity” on the PRACH to support most (but not all!) of MTC use cases
• Cons
• High data rates does not necessarily mean high capacity (in terms of UEs
simultaneously active)
• An LTE cell supporting 10 Mbps as a channel data rate might mean:
• YES: one device downloading a file with ~10Mbps throughput
• NO: 1000s UE simultaneously transmitting at 10 kbps!
• High energy consumption
• Cost
LTE: pros and cons
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201738
LTE vs LPWA
https://www.slideshare.net/DavidBe1/future-wireless-for-iot-by-david-lake-architect-cisco
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201739
• The physical layer of LTE has some interesting characteristics
• OFDM is very flexible, as it allows a variable “composition” of symbols and sub-
carriers
• Symbol duration and sub-carrier spacing can be adapted
• LTE has some built-in mechanisms to reduce energy consumption
• UEs switch to idle mode to reduce the energy consumption
• The energy consumption in idle mode is still high for IoT devices
• The integration of IoT within LTE/EPC networks allows to re-utilize the high-level
procedures already defined
• Authentication, authorization, security
• Reachability of devices
• Mapping to QoS (please note, this doesn’t necessarily mean that IoT traffic has strict
QoS, it means that the operator will know the amount of traffic in the network and will
be then able to perform adequate reservation of resources)
Remarks
Slide subtitle
Massimo CondoluciResearch Associate
Department of InformaticsCentre for Telecommunications Research
King’s College London
Shaping mobile networks for the IoT
Cellular IoT
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201741
• What do we need?
• Lower cost of modules and installation
• This will allow the economy to scale
• Re-using available spectrum and “technologies”
• Simplified transmission/reception hardware
• “Reducing” UE capabilities (e.g., no need for 16/64-QAM)
• Extended coverage
• IoT devices can be deployed outdoor, indoor, deep indoor, underground
• Reducing the sub-carrier spacing (operating with smaller bandwidth
increases robustness of the signal)
• Repetitions
• Lower energy consumption
• Difficulties (i.e., high-cost) in replacing the battery of 1000s of devices, especially
for those in challenging location
• Please note, a duration of 10 years means that.. Once deployed, the technology
needs to be available (without any change!) for.. at least 10 years!
• Introducing new classes of UEs with lower transmission power
• Allowing devices to sleep by improving the idle/connected management
From LTE to.. Cellular IoT
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201742
LTE-M
https://partner.orange.com/open-iot-lab/
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201743
Narrowband-IoT (NB-IoT)
https://www.u-blox.com/en/blog/iot-and-four-reasons-why-licensed-spectrum-technologies-have-been-worth-wait
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201744
Lower cost
https://www.u-blox.com/en/blog/iot-and-four-reasons-why-licensed-spectrum-technologies-have-been-worth-wait
• LTE-M has a
bandwidth of 1.4 MHz
(6 RBs)
• NB-IoT has a
bandwidth of 200 kHz
(1 RB)
LTE
LTE LTE
6 RBs or 1 RB
GSM (200 kHz each)
200 kHz
200 kHz
LTE has a bandwidth from 6 to 100
RBs (typically, 5 MHZ, i.e., 25 RBs)
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201745
Deployment scenarios
http://www.newelectronics.co.uk/electronics-technology/lte-for-the-iot-not-one-standard-but-many/146360/
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201746
Extended coverage
• Lower bandwidth
• Repetitions
Noise FloorWide Band Na
rro
wB
an
d
Same
Power
Better SNR
0 1 2 3
http://www.vodafone.com/content/index/what/technology-blog/nbiot-commercial-launch-spain.html
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201747
Extended coverage
https://ofinno.com/technology/iot/
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201748
Lower energy consumption
• What does it happen during the idle period?
http://www.rfwireless-world.com/Tutorials/LTE-paging-procedure.html
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201749
Lower energy consumption
• What does it happen during the idle period?
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201750
Lower energy consumption
https://www.slideshare.net/qualcommwirelessevolution/paving-the-path-to-narrowband-5g-with-lte-iot
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201751
Lower energy consumption
http://www.mdpi.com/1424-8220/17/9/2008/htm
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201752
Lower energy consumption
http://wireless.electronicspecifier.com/iot-1/making-4g-networks-iot-ready
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201753
LTE-M vs NB-IoT
Coverage measure as Maximum Coupling Loss
Dino Flore, “3GPP standards for Internet of Things,” Feb. 2016
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201754
• Repetitions in NB-IoT are introduced to have different coverage classes
• Variable number of repetitions: 1, 2, 4, 8, ….
• Up to 128 (UL) and 2048 (DL)
• NB-IoT defines three coverage classes
• Normal (outdoor, MCL 144db), Robust (outdoor, MCL 154db), Extreme (deep
indoor/underground, MCL 164db)
• Each channel is repeated a number of times equal to the number of repetitions of the
coverage class the channel is associated to
• Transmission parameters
• MTU Size: 1500B
• Maximum Transport Block Size: 680 DL, 1000 UL (Rel. 13)
• New narrowband channels (limited set compared to LTE)
• NPBCH, NPDCCH, NPDSCH, NPUSCH, NPRACH
• 48 sub-carries reserved for the NPRACH
• Each coverage class has its sub-carrier set and each NPRACH periodicity
Into NB-IoT
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201755
Into NB-IoT
L. Feltrin, A. Marri, M. Paffetti, R. Verdone, “Preliminary evaluation of Nb-IoT technology and its capacity” - Dependable Wireless Communications
and Localization for the IoT, Graz, Austria, Sep. 2017
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201756
• 3GPP has been actively working to meet the requirements of the IoT over
mobile networks
• New features have been added to improve energy efficiency and to guarantee
higher degrees of freedom in terms of reconfiguration
• New features have been added to improve the coverage
• Performance achieved by NB-IoT strongly depends on the deployment scenario
and configuration parameters
• The higher the number of repetitions, the more reliable the communication but the
lower the spectral efficiency
• Optimization between thresholds for the different coverage classes, number of
repetitions, number of assigned sub-carriers and NPRACH periodicity is needed
Remarks
Slide subtitle
Massimo CondoluciResearch Associate
Department of InformaticsCentre for Telecommunications Research
King’s College London
Shaping mobile networks for the IoT
The IoT in the mobile core network
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201758
The core network in 4G
• The CN has the role of:
• Providing connectivity from/to the UE to/from external
Packet Data Networks (PDNs)
• Allocation of IP addresses
• Managing the traffic of the UE according to the
subscription policies
• Authentication and authorization of the UEs
• UE reachability
• Mobility management
Radio Access
Network (RAN)
Core Network
(CN)
MTC Server
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201759
The core network in 4G
Control plane (CP)
User plane (UP)
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201760
The core network in 4G
• Serving/Packet Gateway (S-GW/P-
GW)
• User plane entities, i.e., transport data
packets
• The S-GW is the local anchor point
• The P-GW interconnects to external
networks
• Mobility Management Entity (MME)
• key control plane element
• Security functions (authentication,
authorization, and NAS signaling)
• Device mode (idle, active)
management
• Connection/bearer management
• Handover
• Selection of the S-GW/P-GW
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201761
An eye into the 4G stack
http://hyderabad.locanto.net/ID_1336935306/Wireless-Protocol-Stack-Development-Training.html
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201762
An eye into the 4G stack
• Medium Access Control (MAC)
• Multiplexing/Demultiplexing of MAC SDUs from one or different logical channels onto
transport blocks (TBs)
• Scheduling, LTE channel management
• HARQ
• Radio Link Control (RLC)
• Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM)
• Packet Data Convergence Control (PDCP)
• IP header compression/decompression
• In-sequence delivery
• Cipherying, integrity protection/verification
• Radio Resource Control (RRC)
• Manage the CP between the UE and the RAN (broadcast system information, paging,
security, management of radio bearer)
• Non-access stratum (NAS)
• Manage the CP between the RAN and the CN
• Mobility management, session management, CN bearer management
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201763
An eye into the 4G stack
https://www.tutorialspoint.com/lte/lte_radio_protocol_architecture.htm
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201764
Bearers in 4G
http://www.sharetechnote.com/html/Handbook_LTE_EPS_Bearer.html
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201765
(Simplified) bearerestablishment procedure in 4G
UE1 UE2 UE3 eNB MME S/PGW
Connection Request
Msg1: Preamble
Msg2: RAR
Msg3: Connection
Request
Bearer establishment (UE1)Bearer timer
for UE1Connection Request Request Forward
Bearer establishment (UE2)
Connection Request Request Forward
Connection Request Request Forward
Bearer re-setup (UE1)
Request Forward
Request Ack
Request Ack
Request Ack
Request Ack Bearer establishment (UE3)
Connection Request Request Forward
Bearer re-setup (UE2)Request Ack
Assumption: there is a UP packet sent by the UE after the Request Ack
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201766
(real!) bearerestablishment procedure in 4G
https://www.researchgate.net/publication/264167953_Distributed_Mobility_Management_Scheme_in_LTESAE_Networks/figures?lo=1
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201767
4G connectivity modelapplied to the IoT
• The 4G connectivity model is an always-ON paradigm tailored for MBB
• The UP connectivity is needed to be always “active”
• UP traffic lasts from seconds to minutes (to hours in a boring day/seminar..)
• The long duration of UP traffic reduces the impact of CP signalling
• Example
• Let’s assume there are 7 CP messages among the entities in the CN for the
procedure of connection establishment
• On average, a HTC/MBB session has at least 10s of packets
• MTC has only two packets for each report
• One report from the UE towards the MTC server
• One feedback sent from the server towards the UE after the reception of the
repot (optional)
• We need to take into account the difference between the two scenarios in
the CN as we did in the radio access
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201768
5G use cases
Huawei, “5G Network Architecture – A high-level perspective,” 2016
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201769
Network slicing in 5G
Huawei, “5G Network Architecture – A high-level perspective,” 2016
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201770
The core network in 5G
User plane (UP)
Control plane (CP)
(Radio) Access
Network
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201771
The core network in 5G
• Access and Mobility Function (AMF)
• Termination of RAN CP interface (N2), NAS (N1), NAS ciphering and integrity
protection
• Registration, connection. reachability, mobility management
• Support of authentication, N2, NAS signalling and mobility management for non-
3GPP access
• Session Management Function (SMF)
• Session Management e.g. Session establishment, modify and release, including
tunnel maintain between UPF and AN node
• Selection and control of UP function
• Configures traffic steering at UPF to route traffic to proper destination
• Control part of policy enforcement and QoS
• User Plan Function (UPF)
• External PDU session point of interconnect to Data Network
• Packet routing & forwarding, packet inspection and UP part of Policy rule enforcement
• Traffic usage reporting
• QoS handling for user plane, e.g. packet filtering, gating, UL/DL rate enforcement
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201772
The core network in 5G
• Policy and Charge Function (PCF)
• Supports unified policy framework to govern network behaviour
• Provides policy rules to Control Plane function(s) to enforce them
• Implements a Front End to access subscription information relevant for policy
decisions in a User Data Repository (UDR)
• Unified Data Management (UDM)
• User Data Repository (UDR) - User subscription data, subscription identifiers, etc.
• Front End (FE) - Acess subscription information stored in a UDR
• Application Function (AF)
• Interact with the 3GPP Core Network in order to provide services, e.g.
• Application influence on traffic routing
• Accessing Network Capability Exposure
• Authentication Server Function (AUSF)
• Store/provide authentication information of the UE
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201773
Access independent core
• Non-3GPP InterWorking Function (N3IWF)
• Support of IPsec tunnel establishment with the UE
• Termination of the IKEv2/IPsec protocols with the UE
• Termination and relying of N2 and N3 interfaces to 5G CN for CP and UP, respectively
• Relaying uplink/downlink control-plane NAS (N1) signalling between the UE and AMF
Untrusted Non-
3GPP AccessUE
N3IWF
3GPP
Access
Data Network
HPLMN
Non-3GPP
Networks
UPF
N3 N6
Y1
Y2
AMF SMF
N2
N2N4
N3
NWu
N11
N1
N1
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201774
Access independent core
• N3IWF could allow LoRA, SigFox, etc. to be integrated within the 5G CN
• An operator can manage multiple radio access technologies (RATs)
• Operators could offer the “IoT service” via different RATs
• The chosen RAT can depend on:
• Coverage/planning (NB-IoT is urban areas, LoRA in sub-urban), use case, price/SLA
• The integration of multi-RAT increases the load in the core
• All traffic from all RATs will be managed by the same core
• Load issues, especially for the CP due to the procedures for connection
establishment
NB-IoT
LTE-M
LoRA
SigFoxFixed
5G CN
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201775
URLLC and mMTC slices
George Mayer, 3GPP CT Chairman, “5G Infrastructure Work in 3GPP,” ETSI Summit on 5G Network Infrastructure
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201776
Design drivers for mMTC slice
• Features of IoT traffic to be considered/exploited
• Infrequent transmissions of small packets
• Need for a low CP signalling to improve efficiency in the network
• Very high device density
• Need for a reduction in the UP establishment/management to avoid
congestion issues (a UP node can manage a few milions of bearers
simultaneously)
• This aspect is exhacerbated when considering multi-RAT scenarios
• Static/low mobility
• Some procedures in the CN can be relaxed (e.g., mobility)
• Features of IoT use cases
• Devices belonging to the same use case (e.g., gas metering) have similar traffic
features (e.g., report period, message size)
• Generally speaking, devices can be split into groups, each one gathering
devices requiring the same traffic treatment
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201777
Grouping UEs to reduce the CP signalling
eNB
UE1
UE2
UE3
UE4
UE5
PGW
Bearer UE1
Bearer UE2
Bearer UE3
Bearer UE4
Bearer UE5
4G connectivity
model
AN
UE1
UE2
UE3
UE4
UE5
UPF
Bearer G1
Bearer G2
Bearer G3
5G connectivity
model
G1
G2
G3
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201778
• The mobile core network needs some re-design to efficiently support IoT
• 5G comes in handy allowing flexibility in the core
• A proper management of IoT traffic in the core can have multiple benefits
• Improving efficiency of UP resources
• Reducing CP signalling
• Supporting SLA
• The CN already provides support for “enhanced” services (e.g., multicasting)
which may become of interest for the future of the IoT
• LoRA + NB-IoT + LTE-M + 5G CN = future-proof IoT?
Remarks
Shaping mobile networks for the IoT
Massimo Condoluci ([email protected]) – Bologna, 3 November 201779
Final remarks
• The IoT is evolving, with new use cases being enabled by the availability of
IoT-oriented technologies
• The IoT requires operators to develop new business models/strategies
• (SigFox) LoRA, NB-IoT, LTE-M, etc are complementary technologies tailored
for different markets
• NB-IoT looks to be more flexible and tunable compared to LoRA
• The IoT needs to be properly integrated in the CN, with ad-hoc solutions to
avoid congestion
• What we know: We are currently designing the 5G mMTC slice taking into
consideration the requirements of past/current IoT use cases
• Question: IoT in 2025 - Disruptively different or just «enhanced»?