Examining the Fronthaul Network Segment on the 5G Road Why...

Examining the Fronthaul

Network Segment on the 5G

Road

Why Hybrid Optical WDM

Access and Wireless

Technologies are required?

Philippe Chanclou, Sebastien Randazzo, 18th Annual Next Generation Optical Networking Congress 29th June – 1st July 2016 Day Three, Friday 1st July Nice Acropolis France

The current mobile architecture with distributed RAN equipment.

Antenna

Radio unit

Base band units

Backhaul cell site

Ethernet / Fiber

Central office

CPRI

Backhaul

aggregation

The Radio Access Network architecture : state of art

Radio

BBU

BS

Co

-Ax

Site

Backhaul

Copper

M-Wave

Fibre

Traditional

Site

Standard BS

Backhaul

access

The backhaul cell site is an aggregator of BBUs for data traffic based on

1Gbit/s Ethernet interface with synchronization (SyncE, IEEE 1588).

European benchmark of Ethernet leased line:

Optical Ethernet backhaul

Considering the market for the provision of

‘high quality’ services for business use

(Mobile), this benchmark analysis describes

the availability, standard prices for Ethernet

leased lines supplied by former incumbent

operators in the EU.

A wide variation in charges can be seen

especially at speeds of 100M and above,

which are typically provided via a fibre

connection.

Incumbent reference Offer Ethernet leased line charges

for a local access – 5km – 24 months

source: November 2014, Wik-consult repport

The current mobile architecture with centralized RAN equipment: – Phase1 : BBU centralisation (BBU-RU link based on CPRI/OBSAI)

– Phase 2 : BBU pooling

Optimal architecture for CoMP RAN features (intra and inter-cell sites).

Down sizing the form factor of equipement at the cell site

Antenna

Radio unit

Base band units

Central office

CPRI/OBSAI

over Fiber

The Radio Access Network architecture :

state of art « Cloud RAN »

Phase 1 CRAN

BBU1

Fib

re

BBU2

Fib

re

Backhaul

Copper

M-Wave

Fibre

Backhaul

Copper

M-Wave

Fibre

Central Office

Radio

Site 1

BS

Radio

Site 2

BS

3 cells (1

site) per

BBU

3 cells (1

site) per

BBU

X2

Radio

BBU

BS

Fib

re

Site

Backhaul

Copper

M-Wave

Fibre

Remote Head

Site (RRU)

BBU Remoted BBU Centralised

Backhaul

aggregation

Fronthaul

access

Reach between cell sites and Central office: – For urban area (high &middle density) :

– 75% links have length < 4km



The existing network infrastructure is “compatible” with the fronthaul timing

limitation (RTT < 150µs)

Central office

The Radio Access Network architecture :

state of art « Cloud RAN »

Backhaul

aggregation

Fronthaul access

Cell site to Central office reach

km

Hits

Optical fronthaul (CPRI, OBSAI, ORI)

Passive Active & Semi Active

Fiber-rich

network

to

shared

fiber

Wireless fronthaul (CPRI, OBSAI, ORI)

Native wireless with spectral efficiency

With wireless fronthaul, turn existing macro site into local C-RAN

Easier and faster deployment, same network architecture than short reach fiber

network

From

Small cell

or 4th sector

to

Macro cell

Radio evolutions from 4G Adv to 5G+

Time

300Mbps

1Gbps

2Gbps

25Gbps

100Gbps

Mm Waves

High bandwidth

Full Massive MIMO

More Carrier Aggregation

256 QAM

MIMO 4*4

4G Adv

First 5G

5G+

The ultimate 5G

Exp

ecte

d p

ea

k c

ell

site

th

rou

gh

pu

t

700MHz (wide range of coverage)

3.5GHz with Massive MIMO

Ultra Low latency

The target step of RAN architecture is the virtual RAN where a reconfigurable hardware is used. This architecture facilitates the dynamic adaptation of processing resources to the traffic request of available Radio Access Technology.

Open functional splits with L2 or L1interfaces

The Radio Access Network architecture : the coming « 5G »

L2

L1

F

F

T

ressource

mapping

Q

A

M

F

E

C

R

L

C

M

A

C

P

D

C

P

L3

S

1

R

R

C

X

2

O

A

M

CPRI

OBSAI

CPU & real time constants

Fronthaul bandwidth

Service PDCP

RLC

RLC

MAC

MAC MAC

PHY

Low High

Split

PHY

CPRI

OBSAI

CoMP capability

DPS, CS, CB, … … JT/JR

CoMP: Coordinated Multi-Point

DPS: Dynamic Point Selection

CS: Coordinated Scheduling

CB: Coordinated Beamforming

JT: Joint Transmission

JR: Joint Reception

R

F

BBU L3 & L2… …L2 & L1 RRH BBU & RRH partitioning

vBBU

vBBU L3&L2

Master

central

office

(Data center)

Load balancer

& switch Cell site

aggregator

L1&L2

The low part of the BBU (L1 and potentially a part of L2) cannot be virtualized

due to CPU and real time constraints

The high part can be virtualized (L3 and a part of L2)

The virtualization is explicitly assumed to be part of the 5G architecture and

design principles

vRAN is a prerequisite of the network slicing


Antenna

Radio unit

Ring

Aggregation

Network

Ethernet / Fiber

Access

Network

vBBU L3&L2

Master

central

office

(Data center)

L2 & L3 virtualisation

The optimal architecture for CoMP inter cell sites should request: – L1 & L2 Centralisation

– Pool of cell site aggregators : still CPRI/OBSAI network segments


Antenna

Radio unit

Ring

Aggregation

Network

Ethernet / Fiber

CPRIs over Fiber

Pool of cell

site aggregators

L1&L2

Access

Network

Backhaul & Fronthaul architecture evolution:


Additional data rate:

- minimum +20% of backhaul

- maximum x3 of backhaul

Cell site Access Network Aggregation Network

Ethernet Backhaul

300 Mbit/s (1GEth)

3 sectors

20 MHz – MIMO4x4

BBU

Ethernet New Functional Split

360 Mbit/s < ? < 900 Mbit/s

≈ 2ms / 400 km

vBBU

Cell site

gateway

CPRI : 3 x 5Gbit/s (3 )

≈ 100µs / 20 km

BBU pool

1

2

5

10

25

Gbit/s

3G

2G

CPRI/OBSAI rate per RRH

Compressed CPRI rate per RRH

0.1

Mobile Backhaul and Fronthaul line rate

100

4G to 4G++ 5G to 5G+

Tra

nsm

issio

n li

ne r

ate

Radio Access Technologies

Eth. Backhaul per cell site

Eth. cell site gateway

(new functional split)

Eth. Backhaul

per BBU pool

Mobile backhaul and fronthaul optical technologies

for last miles

Cell site Access Network

(last mile network segment)

Aggregation Network


for last miles

BBU



Aggregation Network

Ethernet backhaul

Switch

FTTH ONT

PtP switch (1G10G 40G 100G)

PtP router

G/XGS-PON (synergy with FTTH roll out)

Ethernet Backhaul

300 Mbit/s (1GEth)

3 sectors

20 MHz – MIMO4x4


for last miles

BBU pool



Aggregation Network

BBU

CPRI/OBSAI/ORI fronthaul

WDM technology : CWDM, DWDM, PtP WDM

Potential synergy with FTTH roll out

(supernumenary fiber, sharing

infrastructure with wavelength overlay)

Transceivers

Mux/DeMUX

CPRI : 3 x 5Gbit/s (3 )

≈ 100µs / 20 km

3 sectors

20 MHz – MIMO4x4


for last miles

BBU

BBU pool

vBBU

Cell site

gateway



Aggregation Network

New backhaul

for new functional split

Transceivers

PtP router (1G40G 100G)

XGS-PON, NG-PON2 TWDM or PtP WDM

(synergy with FTTH roll out)

Switch

FTTH ONT Ethernet New Functional Split

360 Mbit/s < ? < 900 Mbit/s

≈ 2ms / 400 km

3 sectors

20 MHz – MIMO4x4

Optical access trends for Mobile application

Last-mile mobile backhaul context-synthesis: Mobile backhaul is done by DSL or fiber PtP with Switch/Router.

Fiber will the enabler medium of backhauling

Mobile backhaul is already supported by G-PON (with synchronisation feature)

Tomorrow, more antenna sites & more data rate (5G) require:

synergy with FTTx roll out

new PON generation : XGS-PON, NG-PON2 (TWDM & WDM-PON)

FTTH context-synthesis: What G-PON offers in term of bit rate, is enough for the backhaul 2G/3G/4G.

XGS-PON will be soon available to support 5G

WDM in access is in progress by NG-PON2 to support PtP WDM or TWDM (100G)

Data rate capacity of FTTx - PON system

(Down-/Up-stream)

Timeline

2006 2010 2015

2,5/1,25 Gbit/s

XGS-PON

XG-PON 1

G-PON

10/2,5 Gbit/s

10/10 Gbit/s

the potential

25G-PON 25/10 Gbit/s

25/25 Gbit/s

40/10 Gbit/s

80/80 Gbit/s TWDM-PON

&

PtP WDM PON

grey optics

WDM optics

ITU-T G.984

ITU-T G.987

ITU-T G.9807

ITU-T G.989

2018 – 2020 ?

the potential

100G-PON 100 Gbit/s

Optical access trends for Mobile application

4 keys points

1 CPRI fronthaul

experimentations in

France in opportunist

mode

3

Conclusion

2 New functional split based

on Ethernet is coming

for 5G 4 Heterogeneous last-mile:

-PtP Ethernet

(switch/router),

-PON for FTTx synergy,

-WDM for efficient sharing

Fibber has the

preferred medium of

“X”-hauling

Thank You.

Acknowledgment:

Examining the Fronthaul Network Segment on the 5G Road Why...

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