5G Ultra-Reliable and Low Latency Communicationctw2016.ieee-ctw.org/slides/ctw16_Sachs.pdf ·...

5G Ultra-Reliable and Low Latency Communication | IEEE Communications Theory Workshop | © Ericsson AB 2016 | 2016-05-17 |

5G Ultra-Reliable and Low Latency Communications

Dr. Joachim Sachs, Principal Researcher, Ericsson Research


wireless access generations

The foundation of

mobile telephony

The foundation of mobile broadband

Mobile telephony

for everyone

The evolution of mobile broadband

Non-limiting access anywhere, anytime, anyone, anything

~1980 ~1990 ~2000 ~2010 ~2020

5G Ultra-Reliable and Low Latency Communication | IEEE Communications Theory Workshop | © Ericsson AB 2016 | 2916-05-17


Transformed Industries Traditional Industries

Devices Applications

Network

Digitize & Mobilize

Cloud

Transformation



5G – classes of use cases

LOW COST, LOW ENERGY SMALL DATA VOLUMES MASSIVE NUMBERS

ULTRA RELIABLE VERY LOW LATENCY

VERY HIGH AVAILABILITY

Critical MTC

TRAFFIC SAFETY & CONTROL

INDUSTRIAL APPLICATION & CONTROL

REMOTE MANUFACTURING,

TRAINING, SURGERY

Massive MTC

CAPILLARY NETWORKS

LOGISTICS, TRACKING AND FLEET MANAGEMENT

SMART AGRICULTURE

SMART BUILDING

SMART METER

Enhanced Broadband

Smartphones

4k/8k UHD, Broadcasting, VR/AR,

Home, Enterprise, Venues, Mobile/Wireless/Fixed

Non-SIM devices



Critical Machine-Type Communication UlTra-reliable low latency communication

Factory Automation ≤ 1 ms

Motion Control ≤ 1 ms

Smart Grid 3-5 ms

Process Automation 100 ms

Intelligent Transportation Systems 5 ms

Tactile Internet 1 ms

Automated Guided Vehicle 15-20 ms

Numbers are examples, requirements vary within one application area

Remote Control 5-100 ms



5G Radio Access

Evolution of existing technology + New radio-access technology

NR

“Existing” spectrum

Below 6 GHz

Tight interworking

“New” spectrum

Above 6 GHz New spectrum below 6 GHz

Evolution of LTE

1 GHz 3 GHz 10 GHz 30 GHz 100 GHz 1 GHz 3 GHz 10 GHz 30 GHz 100 GHz

No compatibility constraints

Backwards compatible

16 5G Ultra-Reliable and Low Latency Communication | IEEE Communications Theory Workshop | © Ericsson AB 2016 | 2916-05-17


5G Radio Access

Evolution of existing technology + New radio-access technology

NR

“Existing” spectrum

Below 6 GHz

Tight interworking

“New” spectrum

Above 6 GHz New spectrum below 6 GHz

Evolution of LTE

1 GHz 3 GHz 10 GHz 30 GHz 100 GHz 1 GHz 3 GHz 10 GHz 30 GHz 100 GHz

No compatibility constraints

Backwards compatible

16

Spectrum flexibility: licensed, licensed shared, unlicensed FDD, (dynamic) TDD, Full duplex



5g timeplan

Rel-15 Rel-14 Rel-16

5G Study Item NR Phase 1 NR Phase 2

LTE evo LTE evo LTE evo

Requirements Proposals ITU

3GPP

Specifications

2015 2016 2017 2018 2019 2020

IMT-2020



NR – Key technology features

Access/backhaul integration

Integrated D2D connectivity

Massive beam-forming

System control

Separate system-access

functionality

Ultra-lean design

User data

Flexible, scalable and future-proof design

Deployment

Multi-site coordination/connectivity

OFDM-based physical layer

Use cases

Spectrum Minimize network transmissions not directly related to user data delivery

19 5G Ultra-Reliable and Low Latency Communication | IEEE Communications Theory Workshop | © Ericsson AB 2016 | 2916-05-17


LTE › Conventional OFDM › Fixed numerology › Uplink DFT precoding for low PAR (enhanced PA efficiency / extended range)

Waveform – LTE to NR

NR › Conventional OFDM is baseline › Flexible/scalable numerology (sub-carrier spacing, CP, TTI) › Windowing for enhanced spectral confinement for uplink and downlink › Means for low-PAR transmission (e.g. DFT precoding) for uplink and downlink

LTE downlink LTE uplink

NX downlink and uplink

Scalable numerology



Scalable numerology

Frequency domain

Time domain

Lower-frequency/wide-area deployments

Higher-frequency deployments with less time dispersion

Millimeter wave

› Larger sub-carrier spacing at higher frequencies Robust to higher phase noise

› Larger CP for lower frequencies To handle larger time dispersion in wide-area deployments on lower frequencies

› Shorter symbol time at higher frequencies Potential for even lower latency


NR – Scalable numerology

Sub-carrier spacing 15 kHz 30 kHz 60 kHz 120 kHz

Cyclic prefix (µs) 4.7 µs 2.4 µs 1.2 µs 0.6 µs

Subframe [ms] 500 µs 250 µs 125 µs 67.5 µs

Symbols per subframe

7 7 7 7



› Post-IFFT windowing reduces sub-carrier sidelobes Enhanced spectrum confinement

Windowed OFDM

-4 -3 -2 -1 0 1 2 3 4-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

MHz

dB

› Enables mix of numerologies within one carrier – For services with different requirements – Windowing on TX and RX side

Without windowing With windowing

› Similar to “Filtered OFDM” but less complex and higher flexibility



Subframe duration Scheduling Option Optimistic processing

Pessimistic Processing

500 us Dynamic 1.5 ms 2 ms

500 us Instant Uplink Access 1 ms 1 ms


250 us Instant Uplink Access 0.5 ms 0.5 ms

125 us Dynamic 0.375 ms 0.5 ms


62.5 us Dynamic 0.188 ms 0.25 ms

62.5 us Instant Uplink Access 0.125 ms 0.125 ms



500 us n/a 1 ms 1 ms

250 us n/a 0.5 ms 0.5 ms

125 us n/a 0.25 ms 0.25 ms

62.5 us n/a 0.125 ms 0.125 ms

Fdd latency summary FDD Uplink

FDD Downlink

SR

SG

Data

UE BS

New data

SG

Data

Data Available

IUA grant

Data

UE BS

New data

SG

Data

Data Available





500 us Instant Uplink Access 1 ms 1 ms



125 us Dynamic 0.375 ms 0.5 ms


62.5 us Dynamic 0.188 ms 0.25 ms

62.5 us Instant Uplink Access 0.125 ms 0.125 ms



500 us n/a 1 ms 1 ms

250 us n/a 0.5 ms 0.5 ms

125 us n/a 0.25 ms 0.25 ms

62.5 us n/a 0.125 ms 0.125 ms

Fdd latency summary FDD Uplink

FDD Downlink

SR

SG

Data

UE BS

New data

SG

Data

Data Available

IUA grant

Data

UE BS

New data

SG

Data

Data Available

Ultra-reliable and low latency communication

But latency is not sufficient!

It is also about reliability.


(Ultra-) reliability › Providing with high level of certainty

that a message is correctly delivered to the receiver within a latency bound

› Failure if – Message is lost – Message is too late – Message has residual errors

reliability

latency [ms] Guaranteed

CD

F [%

]

100-ε

Focus on the 99.99..9 percentile

95

50

ε can be 10-4 – 10-6

or even 10-9 (e.g. factory automation)


› Manufacturing cell with central controller communicating with sensors and actuators

Wireless communication enables more flexible configuration of manufacturing cells and communication with moving parts

Reliable Real-Time : Example Factory automation

Combination of high reliability and low latency not achievable with current wireless standards

Characteristics Motion control Alarms

Maximum end-to-end latency [ms] 0.5 to 1 1

Jitter [us] <1 –

Packet size [bytes] 10 to 16 2 to 10

Packet loss rate 10-9 10-9

Application availability 99,999 % based on fixed links

› Small message sizes › Periodic traffic

– Time-triggered data generation (e.g. real time motion control)

› Sporadic traffic and alarms – Event-triggered data generation


Transmitter

Latency Budget

Sensor

Actuator

Controller 100 µs

transmission time

• 100 µs transmission time (i.e. 10th of the end-to-end delay budget) • Guarantee for successful in-time delivery (reliability)

1 ms total latency

Device processing Base station & controller processing

Receiver

Base Station


Cost of Guaranteeing high Reliability

High reliability (e.g. 10-5 – 10-9)

-100 -80 -60 -40 -20 0 10 -10

10 -8

10 -6

10 -4

10 -2

10 0

Fading Gain (dB)

CD

F

Rayleigh fading channel

90 dB

50-90 dB fading marging


-100 -80 -60 -40 -20 0 10 -10

10 -8

10 -6

10 -4

10 -2

10 0

Fading Gain (dB)

CD

F

› Diversity may be obtained through – spatial diversity, and – frequency diversity

› Time diversity difficult due to latency constraint

› Coding needed to fully exploit frequency and transmit diversity

Redundancy through diversity

Diversity is key for ultra-reliable communications

-100 -80 -60 -40 -20 0 10 -10

10 -8

10 -6

10 -4

10 -2

10 0

Fading Gain (dB)

CD

F

Div Order = 1 Div Order = 2 Div Order = 4 Div Order = 8 Div Order = 16

18 dB 90 dB

Rayleigh fading channel


› Coding scheme – Block code for packets < 10 bits – Convolutional code for packets up to a few hundred bits

› Code rate – Rate 1/2 – 1/3 good for performance-bandwidth tradeoff – Minimum distance needs to be greater than diversity

order › Higher order modulation

– For devices with good SNR for bandwidth efficiency – To keep code rate low for reliability – Maximum order limited by transmitter and receiver

impairments (EVM)

Coding & Modulation

0 1 2 3 4 5 -105

-100

-95

-90

-85

-80

-75

Minimum bandwidth (MHz)

Req

uire

d re

ceiv

ed s

igna

l pow

er (d

Bm

)

100 bit packet in 0.1 ms, 1x8 antennas

BPSK QPSK 16QAM 64QAM 256QAM rate 1 rate 1/2 rate 1/3


› Latency: access slots ≤0.1 ms – Frame structure enabling low scheduling latency – Slot formatting enabling low processing delay

and on-the-fly decoding – No computationally intensive receiver operation

› Traffic handling: support both periodic and sporadic traffic types – Persistent scheduling for periodic traffic – Dynamic scheduling or contention-based access for sporadic traffic – All with high reliability and low latency

Frame Structure

access slot access slot access slot access slot

data arrival access delay

Ctrl

Data RS


› Robust connectivity via coordinated multipoint communication – via multiple sites – across multiple frequency layers

› Fallback to other RATs (e.g. LTE)

Multi-Connectivity for high Reliability


Software Defined Networking (SDN)

VirtualizationVNF VNF

VNF VNF

Central Data Center

VNF VNF

Distributed Data Center

Network Slicing Distributed Cloud

Flexible Network Architecture

› Network layout for optimized service performance – E.g. local functionality for delay optimization

C-MTC device

C-MTC appl.

C-MTC appl.


5G Network evolution common network for many industries

Critical communications

Massive communications

> 10 years battery lifetime > 80% cost reduction 20dB better coverage

< 5ms E2E delay 99.999% transmission reliability 500 Kmph relative velocity



› ICT is an enabler for industry transformation based on digitized processes – Cellular communications provides ubiquitous connectivity and broad capabilities – One area is ultra-reliable and low latency communication

(or critical machine-type communication)

› Technology components for ultra-reliable and low latency communication – Diversity in space and frequency and robust coding for reliability – Frame format for short delay and on-the-fly processing – Flexible network architecture for service-optimized network design and deployment – Ultra-reliable wireless transmission within 1ms latency is possible

› 5G standardization in 3GPP has started

Summary


› E. Dahlman, G. Mildh, S. Parkvall, J. Peisa, J. Sachs, Y. Selén and J. Sköld, "5G Wireless Access: Requirements and Realization," IEEE Communications Magazine, vol. 52, no. 12, Dec. 2014.

› Ericsson, “5G - key component of the Networked Society,“ RWS-150009, 3GPP RAN Workshop on 5G Phoenix, AZ, USA, September 17 – 18, 2015 http://www.3gpp.org/ftp/workshop/2015-09-17_18_RAN_5G/Docs/RWS-150009.zip

› O. N. C. Yilmaz, Y.-P. E. Wang, N. A. Johansson, N. Brahmi, S. A. Ashraf and J. Sachs, “Analysis of Ultra-Reliable and Low-Latency 5G Communication for a Factory Automation Use Case,” in IEEE ICC, London, Jun. 2015.

› N. A. Johansson, Y.-P. E. Wang, E. Eriksson and M. Hessler, “Radio Access for Ultra-Reliable and Low-Latency 5G Communications,” in IEEE ICC, London, Jun. 2015.

› J. Sachs, P. Popovski, A. Höglund, D. Gozalvez-Serrano and P. Fertl, “Machine-Type Communications,” book chapter in “5G Mobile and Wireless Communications Technology,” ISBN 9781107130098, 2016, www.cambridge.org/9781107130098

› S. A. Ashraf, F. Lindqvist, B. Lindoff, R. Baldemair, "Control Channel Design Trade-offs for Ultra-Reliable and Low-Latency Communication System", IEEE Globecom Workshop on Ultra-Low Latency and Ultra-High Reliability in Wireless Communication, San Diego, USA, December, 2015.

› N. Brahmi, O. N. C. Yilmaz, K. W. Helmersson, S. A. Ashraf, J. Torsner, "Deployment Strategies for Ultra-Reliable and Low-Latency Communication in Factory Automation", IEEE Globecom Workshop on Ultra-Low Latency and Ultra-High Reliability in Wireless Communication, San Diego, USA, December, 2015.

› A. Osseiran, J. Sachs, M. Puleri, ”Manufacturing Rengineered: robots, 5G and the industrial internet, Ericsson Business Review, no. 4, 2015, https://www.ericsson.com/res/thecompany/docs/publications/business-review/2015/ebr-issue4-2015-industrial-iot.pdf

› J. Torsner, K. Dovstam, G.Miklós, B. Skubic, G. Mildh, T. Mecklin, J. Sandberg, J. Nyqvist, J. Neander, C. Martinez, B. Zhang, J. Wan, “Industrial RemoteOperation: 5G rises to the challenge,” Ericsson Technology Review, vol. 92, http://www.ericsson.com/res/thecompany/docs/publications/ericsson_review/2015/etr-5g-remote-control.pdf

REferences


http://www.3gpp.org/ftp/workshop/2015-09-17_18_RAN_5G/Docs/RWS-150009.zip







http://www.cambridge.org/9781107130098

https://www.ericsson.com/res/thecompany/docs/publications/business-review/2015/ebr-issue4-2015-industrial-iot.pdf












http://www.ericsson.com/res/thecompany/docs/publications/ericsson_review/2015/etr-5g-remote-control.pdf









To know more about our 5G visit http://www.ericsson.com/spotlight/5G

http://www.ericsson.com/spotlight/5g

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