ran slicing as enabler for low latency services ran slicing as enabler for low latency services ......

2016 Nokia1

RAN slicing as enabler for low latency servicesPresented by A. Maeder, NOKIA Bell LabsContributions by Z. Li, P. Rost, C. Sartori, A. Prasad, C. Mannweiler

ITG 5.2.4 Fachgruppentreffen

Dresden, June 10th, 2016

2016 Nokia2

Outline

Low latency-services

Which services are we talking of?

Requirements

What is RAN slicing and why do we need it?

Principles of RAN slicing

Architecture enablers

Enabling low latency services in a common infrastructure

Outlook

RAN slicing as enabler for low latency service

2016 Nokia3

Low-latency use cases


3

Real-time remote diagnosis

Real-time remote avatar

Augmentedreality

Hazard

Automotive

4x more cars

possibleSafer and faster individual transport

cooperation

Coordination

Industry 4.0

Computation

Control0.5ms 10ms

2016 Nokia4

Diversity of use cases

10 yearson battery

10-100 10 000

2016 Nokia5

Mobile Network TopologyLarger European operator

macro

macro

pre-aggregationsmall cells

small cellsmacro

x10.000 macro sites

x100.000 small cells

x1.000 pre-aggregation

sites

centralgateways

CN functions

x100 aggregation sites

x10 central

gateways

aggregation

site

Internet

Operator services

edgecloud

edgecloud

star

chain

tree

Internetring

= potential site for data center/aggregation/local breakout point

RRHs

Diverse x-haul, network topologies, aggregation scenarios

macro

Distance and latency to radio access increases

Local breakout

and functions

2016 Nokia6

Network and RAN slicingFlexibility to support different use cases in the same physical network

UE Edge Aggregation Core

Inte

rne

t/Se

rvice

do

ma

in

Access

Enhanced Mobile Broad Band Slice

IoT Slice

Low Latency Slice

Radio front end RAN higher layers (eMBB)

Gateway

Radio front endRAN higher layers (IoT)

Gateway

Radio front end RAN higher layers (URLLC)

Gateway

2016 Nokia7

Isolation of radio resources:

in order to fulfil slice-specific service level agreements (SLAs).

Function of the QoS framework and can be enforced by resource scheduling on MAC or on higher layers.

Isolation of processing resources for network functions, e.g. if network functions are operating in a virtualized environment.

Cryptographic isolation between slices, by providing cryptographic keys to the corresponding encryption function in RAN.

Isolation requirements

2016 Nokia8

RAN slicing basic concept

RAN slicing as enabler for low latency serviceS

lice

MN

O1

, cM

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ork D

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PHY-L

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RLC

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RLC

RRC RRC

Ne

two

rk M

an

ag

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nd

Orc

he

stra

tio

n (N

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)

MNO specific

scheduling

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ltip

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ult

iple

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iple

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PDCPRRC

Air Interface

Se

rvic

e

Se

rvic

e

MNO specific

scheduling

MUX

MUX

MAC MAC

RRC RRC

MNO specific

scheduling

MNO specific

scheduling

MAC 3

PDCP 3 RRC 3

PHY 3

MUX

Se

rvic

e

Se

rvic

e

Se

rvic

e

Se

rvic

e

Se

rvic

e

Se

rvic

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rvic

e

Se

rvic

e

Se

rvic

e

PHY 3PHY 1 PHY 2

MAC 1 MAC 2

RLC 1 RLC 2RLC 3

IF* IF* IF* IF* IF* IF*

PHY PHY

Example A:RAN Slicing down to PHY

Example B:RRC Slicing and PDPC based MC

Example C:No RAN Slicing, MAC based MC

2016 Nokia9

Basic architecture concept in 5G


RAN

MC-Anchor

RRC

Slice

A

Radioaccess point 1

Radio access point 2

User device

Service traffic flow A

Slice

B

Service traffic flow B

Policy/Key

MC-Anchor

Radio flow A

Radio

flow B

Control signaling

Control signaling

CP

UP

NS

SF

NSSF: Network Slice Selection Function

2016 Nokia10

+

Exploiting air interface flexibilityMapping to lower layers

Use

r 1

Use

r 1

User 2

User 3 User 5

User 4

User 2

Use

r 5 U

ser

1

Use

r 1

User 3

Use

r 1

User 4

However, trade-offwith cell capacity (multi-user diversity gains) need to be considered

Different TTI length per tile as enabler for slices with low-latency requirements

time

fre

qu

en

cy

t

f

Short TTI Long TTI


2016 Nokia11

On all nodes:- Processing delay- Packet buffering- Multiplexing (e.g., TDM)

Where does delay come from?


ServerUE BS switches Router

Air interface:

- Frame alignment/TTI- Resource request (UL)

- RACH (UL)

- HARQ

Buffering

On all links:- Transmission delay- Duplex (e.g., TDD)

2016 Nokia12

Air interface latency in 5GFDD, 0.125ms subframe length, 0.1ms processing in DL, 0.15ms in UL

Downlink Uplink~ 0.45ms

~ 0.9 ms

~ 1.2 ms

Source: NOKIA Networks, R1-165028; URLLC U-Plane Latency Analysis

Target: 0.5ms in UL and DL

2016 Nokia13

What to do in 5G?


Air interface:

- Shorter TTI/subframe (0.125 ms)

- Bi-directional subframes

- Shorter processing times (10x reduction)

- Robust coding/no or low #HARQ

retransmissions

- Resource pre-allocation (e.g., semi-persistent scheduling avoid resource request)

- Enhanced random access (e.g. 1 or 3

step instead of 5 step)

- Service-aware RRM

- Enhanced mobility mechanisms

- Device-to-device communication

- Multi-connectivity schemes

On all nodes:- Reduced processing delay

(10x reduction)- Priority queuing very small

buffers- Low number of hops to

reduce instances of processing and buffering

- Path switching instead of packet switching

E2E architecture view- Functions close at

network edge- Mobile edge computing

optimized for low-latency

- Local area routing- End-to-end QoS

enforcement - Resource isolation

and/or dedicated infrastructure for low-latency

- Centralized resource coordination

2016 Nokia14

Support for low-latency in unified architectureScenario: support of mobile broadband and ultra low latency

uGW

NG

1-C

NG

1-U

anchor

MSM

5G-NB

X2*

NG

1-C

NG

1-U

anchor

X2*

uGW

NG

1-U

Uu* Uu*

Service Flow 2

V2X

Low-latency, high reliablility

service cloud

Internet

Service Flow 1:

Mobile Broad

Band

NG1-C

Split bearer at secondary nodeMay be located

in RAN cloud

2016 Nokia15

Summary and Outlook


Network and RAN slicing are key concepts for 5G

Enables flexibility for different use cases in the same network

Reduces management and maintenance efforts

Low latency services enabled by function optimization and deployment flexibility

Configuration and optimization across all RAN functions

New resource management schemes needed

Flexible architecture concepts to support different use cases

16 Nokia 2016

System of systems

Practicalities PotentialsVersatileradio

Possibilities

Key to the programmable world

People & Things


2016 Nokia17

References


[1] NGMN Alliance, Description of Network Slicing Concept, January 2016

[2] NOKIA Networks, R1-165028; URLLC U-Plane Latency Analysis, 3GPP RAN1#85, May 2016

[3] 3GPP, TR 38.913 V.0.3.0; Study on Scenarios and Requirements for Next Generation Access Technologies, May 2016

2016 Nokia18

Definitions


Source: NGMN

ran slicing as enabler for low latency services ran slicing as enabler for low latency services ......

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