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
RAN slicing as enabler for low latency service
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
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ork D
om
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rk D
om
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PHY-L
PDCP
RLC
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RLC
RRC RRC
Ne
two
rk M
an
ag
em
en
t a
nd
Orc
he
stra
tio
n (N
MO
)
MNO specific
scheduling
Mu
ltip
lexi
ng
Po
licy
Fu
nct
ion
(MN
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pe
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ult
iple
xin
g P
olic
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ctio
n(a
cro
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ult
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
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Se
rvic
e
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Se
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Se
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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 slicing as enabler for low latency service
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
RAN slicing as enabler for low latency service
2016 Nokia11
On all nodes:- Processing delay- Packet buffering- Multiplexing (e.g., TDM)
Where does delay come from?
RAN slicing as enabler for low latency service
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?
RAN slicing as enabler for low latency service
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
RAN slicing as enabler for low latency service
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
RAN slicing as enabler for low latency service
2016 Nokia17
References
RAN slicing as enabler for low latency service
[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
RAN slicing as enabler for low latency service
Source: NGMN
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