front-haul networking for 5g: an analysis of ... -...

HUAWEI TECHNOLOGIES CO., LTD.

Front-haul networking for 5G:

An analysis of technologies and

standardization

Hassan Halabian

[email protected]

Canada Research Center

November 2017

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 2

Cloud-RAN

Advantages:

Simplify the RRH site – Full outdoor, low cost

Better RAN network performance - Facilitates cooperative radio schemes, e.g., ICIC, CoMP, Massive MIMO

Future oriented – RAN virtualization

Fronthaul


CPRI widely Deployed For 4G

CPRI is - TDM based synchronous

interface/ Symmetrical serial data

link/Steady data stream, ”Always on”

Embedded Ethernet or HDLC streams

(C&M plane data)

I/Q data is the time samples of the wireless

analog signal (Data plane)

Front-haul capacity linearly scales with

Number of antenna ports/Number of sectors

Sampling rate (Radio spectrum BW)/I/Q bit-

width

Transmission overhead (coding and headers,

etc.)/compression factor etc

BER=10-12


Facing high bandwidth challenge

Big challenge for Massive MIMO (64T/64R) – Beyond

100Gbps requirement

But the real fronthaul bandwidth depends on configuration

– air spectrum bandwidth, Massive MIMO types etc

If Use 4G RAN Architecture for 5G

5

160

0

50

100

4G 5G

(Gbps)

x32with 4:1 compression

20 4

160

64

bandwidth（MHz）

Antenna num

4G

5G

x8 x16

CPRI Split Point

50~130 usBandwidth Boosting Sharply


eCPRI Protocol Stack

eCPRI Laye1: eCPRI over electrical cable

eCPRI over electrical backplane

eCPRI over optical fiber

eCPRI over Ethernet:

eCPRI messages shall be transmitted in

standard Ethernet frames

eCPRI over IP:

eCPRI messages shall be transmitted in

UDP/IP packets

Ethernet, VLAN (priority tag), MACsec

IP, IPsec

UDP

eCPRI specific protocol layer

User DataReal Time

C&M

eCPRI Services

IP,

IPsec

UDP, TCP,

SCTP, etc.

e.g.

SNMPPTP

C&M Synchronizationother eCPRI

services

SyncE

IP

UDP

Connection OAM

Ethernet

OAM

IP,

IPsec

UDP, TCP

ICMP

Transport Network Layer

Physical Layer

eCPRI Layer

User Sync Control

& Mgmnt

eRadio Equipment Control (eREC)

Transport Network Layer

Physical Layer

eCPRI Layer

User Sync Control

& Mgmnt

eRadio Equipment (eRE)

Transport Network

Fronthaul Network


When compare CPRI with eCPRI, we found more

challenges

If Use New RAN Architecture for 5G

1: 5G AAU weight increasing

Compared with CPRI part Phy function

embedded in 5G AAU

2: 5G AAU upgrade when add new

features

With Low Phy High Phy

3: Do not forget 4G: CPRI + eCPRI

•Ignore RAN challenges

•eCPRI used for fronthaul

10~25 Gbps

50~130 useCPRI Split Point


Possible 5G Fronthaul Solutions

Increasing 5G site number faces fiber limitation

Possible transport solutions:

CPRI&eCPRI CPRI&eCPRI

Scenario2: WDM

CPRI&eCPRI

CPRI&eCPRI

Scenario1: Eth based

Scenario3: PON

Limited fiber resource Site number increasing due to 4.5GHz/28GHz

Scenario4: MicrowaveE-band

4G BBU

5G CU/DU


Eth based Fronthaul Research Introduction

RAN Requirements

Define RRH/BBU Interface Implementation

Fronthaul Requirements Side

•Current focus: Profile(s) for current (CPRI 7.0)

•Next step is eCPRI

• Joint effort with CPRI Cooperation

• Joint effort with IETF DetNet WG

Last PAR 2018/07, SA Revcom approval: 2019/05

802.3br and 802.1Qbu : Frame preemption

802.1Qbv – Traffic Scheduling (time-gated queues)

Ethernet Based Fronthaul Network

• Another Team for Fronthaul based on Eth

• Already demo for CPRI over Eth

• Define new Eth Type for Fronthaul


IEEE 1914.3 – CPRI over Ethernet

Standard for Radio Over Ethernet (RoE) Encapsulations and Mappings, defines

The encapsulation of digitized radio

mapper/demapper functions to transfer CPRI streams over Ethernet.

The header format for encapsulation of existing digitized radio transport formats.

Three types of encapsulation techniques

structure–agnostic mapper: is only a container for the encapsulated digitized radio transport frames.

structure-aware mapper: has detailed knowledge of the encapsulated digitized radio transport format content

native RoE packet.

1914.3 eCPRI

Technology Only Ethernet UDP/IP/Eth and Eth. - any packet transport

Bandwidth CBR (CPRI encapsulation) and VBR (Native RoE only) User traffic related, VBR( ~10 fold reduction)

Topology P2P connection, P2P/Chain/Ring P2MP connection, flexible topology

RAN IQ time domain and freq. domain data (Native RoE only) Any functional split

Proprietary Performance

Enhancement Support

Limited Yes


IEEE 802.1 TSN Technology Overview

TSN Standards

LatencyBounded low latency:

Credit Based Shaper (802.1Qav)

Frame preemption (802.3br &

802.1Qbu)

Scheduled Traffic (802.1Qbv)

Cyclic Queuing and Forwarding

(802.1Qch) Asynchronous Traffic

Shaping (P802.1Qcr)

Reliability

Ultra reliability:

Frame Replication and Elimination

(P802.1CB)

Path Control and Reservation (802.1Qca)

Per-Stream Filtering and Policing

(802.1Qci)

Reliability for time sync (P802.1AS-Rev)

SynchronizationTime synchronization:

Timing and Synchronization

(802.1AS) includes a profile of IEEE

1588

Zero congestion loss

Resource Mgmt Dedicated resources & API

Stream Reservation Protocol (802.1Qat)

TSN configuration (P802.1Qcc)

YANG (P802.1Qcp)

Link-local Registration Protocol

(P802.1CS)

Converged network for Information Technology (IT) and Operational

Technology (OT) in LAN

Multi profiles for different applications – Video, Factory, Telecom…


Eth based Solution – Prototype Test

2016 – Lab POC, CPRI over Eth via PW(same as E1 PW), FlexEth;

No bandwidth saving, device needed when CPRI and eCPRI at the same site

3 × CPRI 7

（9.8304Gbps）encapsulation 40GE（NNI）IF

FPGA based, only lab POC

PW for CPRI

Eth

FlexEth

MAC

Shim PHY

Bonding

MAC

Subrate

EthChannelized

CPRI

Encapsulation of CPRI frame Multiplexing with FlexE


WDM Based Solution – FO/Colorless Module

15*Any Port

GE~10G

• Full Outdoor, w/o

site configuration

• Bi-Di, with 1+1

protection

• w/o optical layer

commissioning

O/E

Map/

Demap

OTN

OH oDSP

Colorful IF

E/O

2x50G

Current FO Solution

BBUOSN 1800

Centralized WDM Solution(Under R&D)

AAU

AAUCloud BB

Colorless SFP+

BiDi

Optical distribution

box

Shared laser (10 directions)passive

multiple wavelengths

Shared laserColorless SFP+(10G/25G)

…

GC Site

Compatible with CPRI/eCPRI – transparent for any traffic

Simple, low power consumption and save site fibers – without device


PON Based Solution–– Optimized DBA Algorithm

DBA logic

DBA report

Allocation

Time slot

SR T-CONT

NSR T-CONTScheduler

ONUPON Board - OLT

Control plane

Date plane

Current NG-PON DBA ：350~550us DBA Optimization for 5G：50us~100us

• Assured-DBA/Max DBA, status report before bandwidth allocation : 1-2ms.

• Fixed-DBA, no need status report, delay will be 100-200us

• Periodic windowing, add delay 200-300us

SR-DBA

NSR-

DBA

Periodic

windowing

DBA logic

SR-DBA

NSR-

DBA

Periodic

windowing

DBA logic

SR-DBA

NSR-

DBA

New Periodic

windowing

Mechanism

LL-DBA

• LL-DBA, low latency DBA in future, delay will be about 50us~100us.

• Periodic windowing should have new mechanism to eliminate latency to

0.Notes: chipset and hardware must be changed to

support 50us~100us low latency DBA


Fronthaul Solution Summary

1WDM - Colorless

2Eth – RoE

4PON

• Transparent for CPRI/eCPRI: 4G&5G Compatible

• No site device: Simple, low power consumption

• Innovation: new optical module

• CPRI mapper/demapperneeded

• Limited functional splitting available

• Utilize the L2 switch supply chain

• Only Eth transport

• Reuse the existing ODN

• Upgrade PON capacity and optimize the DBA algorithm

3IP/Eth – eCPRI

• Open for performance enhancement

• Support any packet transport

• Flexible function splitting

• No support for CPRI

Thank youwww.huawei.com

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