Bristol 5G city testbed with 5G-XHaul extensions

IMPACT OF 5G RAN ARCHITECTURE IN TRANSPORTNETWORKSDaniel Camps (i2CAT)ONDM 2018 – Optical Technologies in the 5G era (Workshop)

OUTLINE

¢ From 4G to 5G architecture¢ The F1 interface and new RRC states¢ The F2 interface (3GPP and eCPRI)¢ 5G deployment options¢ 5GXHAUL/5GPICTURE’s view on a converged 5G

transport¢ Thoughts on transport support for 5G QoS¢ Conclusions

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FROM 4G TO 5G ARCHITECTURE

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E-UTRAN (LTE)

eNB(RRH-BBU)UE

X2S1-MME

S1-U

Serving Gateway

PDN Gateway

S5

S10HSSS6a

PCRF

Gx

PDNs

APNs

SGiU-PlaneC-Plane

EPC

MME

S11

S1-C

5GNR

gNB-CUUE

Xn N2

N3

UPF UPFN9

N14AUSF

PCF

DNNs

APNs

N6U-PlaneC-Plane

5GCore

gNB-DU

F1

RRH

F2

SMF

N4AMF

N11

NSSF

N7

N1 (S-NSSAI)

N12

N22

F1 INTERFACE AND NEW RRC STATES

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¢ F1 functions:� Mgmt CU-DU (discovery, reset, etc) � SIB delivery from CU to DU� UE context mgmt: F1 sessions

maintained per UE

Radio Network Layer

UDP

IP

Data link layer

Physical layer

TransportNetworkLayer

GTP-U

User Plane

SCTP

IP

Data link layer

F1AP

Physical layer

Radio Network Layer

TransportNetworkLayer

Control Plane

gNB-CU

gNB-DU

SDAPPDCP

RLCMACPHY

F1

Non-Real time

Real time

RRC

WT802.11

Non-3GPP

XwRLCMACPHY

Real time

F1

IP flow anchoring

F1 INTERFACE AND NEW RRC STATES

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gNB-CU

gNB-DU gNB-DU gNB-DU

gNB-CUXn

F1 F1 F1

UE

AMF

N2 N2

intra-CU F1 handover inter-CU F1 handover

RRC ConnectedN3:

ESTABLISHEDF1:

ESTABLISHED

RRC IdleN3: RELEASEDF1: RELEASED

RRC InnactiveN3:

ESTABLISHEDF1: RELEASED

UE RRC STATES

Location kept by gNB-CU in terms of RNA (RAN Notification Areas)

F2 INTERFACE (3GPP AND ECPRI)

¢ Not much progress inside 3GPP à Work in parallel carried out by eCPRI¢ A variety of potential splits considered

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eCPRIsplit E

eCPRIsplit D

eCPRIsplit C

eCPRIsplit B

eCPRISplit A

eCPRIsplit ID

eCPRIsplit IIDsplit IU

I/Q Time Domain

I/Q Freq. Domain

5GPICTURE D4.1 - http://www.5g-picture-project.eu/

F2 REQUIREMENTS SUMMARY

¢ From eCPRI spec� 3/1.5 Gbps user throughput� 500 PRBs� 8/4 DL/UL MIMO layers

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� 64 Antennas� Digital BF in eREC� 256QAM� IQ 30 bits/sample

F2 INTERFACE SCALABILITY [1]

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10G Ethernet, ~CPRI rate 8àcan support only 4G, low load/split C, no support of 5G split E’/full centralization

400G Ethernet (IEEE P802.3bs)àsupports all splits/RATs

àfor 5G split E’/full centralization only a few cells can be aggregated in one link

4G4G

Split E’Split IID

Split B

Split E’Split IID

Split B

[1] Bartelt, Jens, et al. "5G transport network requirements for the next generation fronthaul interface." EURASIP Journal on Wireless Communications and Networking 2017.1 (2017): 89.

5G DEPLOYMENT OPTIONS

9(*) 5G-RAN target OWD delays: 4 ms eMBB, 0.5 ms URLLC[1] Andy Sutton, BT, 5G Network Architecture, available at: https://www.youtube.com/watch?v=aGEAQJ7U1tA

DU

CU

DU

CU

DU

DU

Small Cell - CU

DU

DU

RRH

Macro-CU UPF

App server

App server App

server

UPFUPF

MECMEC 5GCore

App serverMEC

Internet

mmWave – 60GHz

Aggregation CoreAccess

mmWave26/28GHz(reqs. > 10 GBps)

100 MHz – 3.5 GHz(reqs.~ 10Gbps (F1))

Macro-DU

UPF location [1] Access Aggregation Core

Num. Sites 1200 106 10

Transportlatency

0.6 ms 1.2 ms 4.2 ms

Estimated 5G latency (*)

9.2/2.2 ms (eMBB/URLLC)

10.4/3.4 ms(eMBB/URLLC)

16.4/9.4 ms(eMBB/URLLC)

Access fibre, e.g. WDM-PON

NFVI NFVI NFVI

5GXHAUL/5GPICTURE’S VIEW ON A MULTI-TENANT 5G TRANSPORT

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Data Plane

Control Plane

Data plane- ETN (interface PNF/VNF) – IATNs

(stich transport domains)- Per-tenant state at the edge- MACinMAC transport

(pathID+sliceID)

Control plane- Hierarchical- L0 – tech domain aware- L1 – tech domain agnostic- RAN – Transport interface- Synch Harmonizer

THOUGHTS ON TRANSPORT SUPPORT TO 5G QOS

¢ F1, N3, Xn, Xw interfaces are all based on GTP

� GTP TEID identifies per-UE sessions

� GTP extension header will carry the 5G QoS Flow ID (QFI)

¢ Can we directly map 5G QoS to transport flows (at least at the edge)?

� i.e. establish transport flows according to UE’s RRC transitions

¢ Analysis performed based on an operational LTE network in Greece (33

cells)

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State maintained at each transport node Signalling load with transport controller

SUMMARY AND CONCLUSIONS

¢ 5G RAN base station decomposed into RRH – DU – CU

¢ “Backhaul-like” F1 interface below PDCP between CU and DU

¢ Multiplicity of options (functional splits) between DU and RRH

¢ 5G’s flexibility provides built-in support for low latencyapplications within the network

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Thanks for your attention!

Questions?