Synchronization Requirements for RAN & Backhaul Update

draft-zhou-tictoc-ran-sync-req-01.txt

Xiaodong Duan, Lan WangChina Mobile

Version Update

• New version submits– draft-zhou-tictoc-ran-sync-req-01.txt

• Update– Phase sync accuracy of RAN system in TD-SCDMA reaches agr

eement• Accuracy among NodeBs: 3us• Accuracy between NodeB and reference clock: 1.5us

– Phase sync accuracy of RAN system in TD-LTE is under discussion

• Accuracy among NodeBs: 1~3us

– Requirements for 1588v2 backhaul

Requirements UpdateBase station

Base station controller

Base station

UE

UE

RadioInterface

SYNC

Ref. Clock

Network SYNCNode SYNC

Layer Sub Items Frequency Accuracy Phase Accuracy

Network Sync E1 50ppm -

STM-N 4.6ppm -

PTN Not so strict -

Node Sync Controller-Base station

If provide location service, TBD If provide location service, TBD

50ppb(Time alignment over Iu) 1.5us(Time alignment over Iu)

Inter-Base station 50ppb 3us(TD-SCDMA&TDD LTE)

BS-Reference clock 50ppb 1.5us(TD-SCDMA&TDD LTE)

Radio interface GSM 50ppb -

TD-SCDMA 50ppb 3us

TDD LTE 50ppb 1-3us

Urgent requirements for RAN Sync

• Most operators have choice LTE as their evolution of 2/3G network– TDD based LTE has just been introduced– TDD LTE has higher sync requirement than FDD

• The requirements for RAN is clear and urgent– Radio Access Network is on the early stage of moving to IP

transport– GPS is the only solution so far

• The total technologies/solutions should be deployed within one year----Urgent!!– TICTOC should accelerate its work

Example:Current 3G/TD-SCDMA Networks

RNC

NodeB

NodeB SDH

ATM

ATM

• Currently, each nodeB has a GPS antenna--Not so good!– COST: you can imagine 10000 BSs in one city– Uneasy deployment: affect the flexible deployment of BS– Other

• Security/Reliability

Mobile backhaul

IP/MPLScore

RNC

PBT802.1ad

DLS

PON

RNC

IP/MPLScore

RNC

TMPLSTMPLS

RNC

TMPLS

RNC

IP/MPLScore

RNC

MPLS AGGVLL/VPLS

MPLS Access

802.1ad

CoreAggrAccess

NodeB

NodeB

NodeB

NodeB

NodeB

NodeB

NodeB

802.1ad/ PON / M

PLS

PBT/ TMPLS/ MPLS/ VPL

S/ IP

IP/MPLS Core

Backhual sync transmission• Two sync transmission mode should be considered

– Core network sync distribute—sync are distributed to local clock• 1588v2 over IP/MPLS core

– Core to edge- local clock are distributed to Edge Node (such as BS)• IEEE1588 or other must be extend to used within different backhaul technology, such

as– MPLS/IP– PON– 802.1– PBT– TMPLS

• The protocols designed by TICTOC should considered– Reliable transmission– Security– Retransmission/Verification– Suit for different kinds of backhaul

• How to Work with Multicast Technologies to reduce overhead

Summary• RAN requirements for sync are more clearly now and TD

based LTE has high sync requirements

• It better for us to provide solutions with 1years, so that the industry can used it ASAP

• Most operators are replanning their Mobile Backhaul to meet the high bandwidth, the sync protocol should be considered

• Telecom profiles of sync protocol– network scale/ network load/ local clock accuracy– Reliable transport/ security/ efficiency/ Retransmission/Verificatio

n– Multicast

Thank you&Any questions?