LTE ASIA 2013 Examining new backhaul requirements for LTE

Date : 19 September 2012

Confidential

3G/2G and TDM transport

RNC

BSC MGW

SGSN

MSC

GGSN NodeB

BTS

3G/2G traffic only require point to point connection towards respective controllers

Use of TDM transport equipment in the backhaul are still feasible provided with sufficient capacity

IP/packet technologies offers easier provisioning of backhaul and better QoS

< FastEth / E1 > < GE/EoS > < N X 10 GE >

IuB

A

Key requirements for LTE backhaul

Bandwidth

Latency

Efficiency

Packet Synchronization

LTE and its backhaul

eNB requires more logical connectivity compared to 3G/2G

X2 logical interfaces are required for session and payload handover between eNBs

A flexible and robust backhaul design is required to support LTEs dynamic traffic behaviour

Additional bandwidth will be required for eNB connected to different

backhaul access node

S-GW

MME

P-GW

eNodeB

eNodeB

eNodeB

S1-U

S1-MME

X2

Access Aggregation Core

X2

< 100 GE > < N x 10GE > < 10GE >

LTE-A Coordinated Multi Point

CoMP requires multiple copies of session and payload to be replicated across adjacent eNB

Inter eNB CoMP connected to separate backhaul access nodes will generate more traffic towards the backhaul aggregation and access

Require PTP 1588 phase synchronization to achieve sync accuracy across eNB

eNodeB

Access

Aggregation

eNodeB

eNodeB

Backhaul Evolution

TDM transport typically are built in rings

PTN technology offers packet based transport systems however limited to Layer 2 only

IP/MPLS based backhaul equipments require tiered fiber architecture to optimize cost for capex and efficient traffic.

SDH SDH

SDH SDH

SDH SDH

SDH SDH

SDH SDH

Packet Synchronization PTP 1588v2

Frequency sync is used across 2G/3G/LTE

GPS is widely used as an alternative to phase sync as there is no finalized user profile by IETF

Phase sync is also required by LTE-FDD for

LTE-A CoMP

Hetnet

Location based services

eNBMS services

Potential issues with PTP 1588v2

Asymmetric fiber introduces transport delay variance

No finalized standardization of transparent clock for phase sync implementation for bandwidth wholesale provider

Risk of bad accuracy if backhaul topology is not optimized

THANK YOU

Email: tiloong@digi.com.my