Phase synchronization proposal over the transport network for LTE-Advanced

1

Author: Eng. Claudia Carballo González

Transmission Planning Department, ETECSA

Introduction*

2

Evolution of mobile broadband technologies.

• Higher bandwidths

• High demands of QoS

• A rapid increase in global mobile data traffic

• Higher capacities in transmission equipment

• Tight latency and synchronism requirements

Introduction**

3

Synchronism starts to play a central role in packet networks.

• It allows reaching the required bandwidths.

• Avoid unacceptable levels of bit shifts.

• Prevents data loss and retransmission delays.

• Prevents video degradation and falls in communication systems.

Problems in synchronism have an impact on customer satisfaction andsupplier revenue.

.

5

Application Frequency/air interface

Time/phase Why you need to comply

LTE-FDD 16/50 ppb N/A Call initiation, spectral efficiency, data integrity

LTE-TDD 16/50 ppb ±1,5 µs a 5 µs Time slot alignment, spectral efficiency, data integrity

LTE MBSFN(TDD or FDD)

16/50 ppb ±500 ns a 1,5 µs Proper time alignment of a video signal decoding from multiplebase transceiver stations.

LTE CoMP/MIMO (TDD or FDD)

16/50 ppb ±500 ns a 1,5 µs Coordination of signals to/from multiple eNodeBs.

LTE-eICIC 16/50 ppb ±1,5 µs a 5 µs To mitigate the interference is required tight coordination betweeneNodeBs.

LTE CA 16/50 ppb ns (TAE --- TimeAlignment Error)

Stringent demands on the timing of frames utilized at the edge of the network to switch various air frequencies in use.

Mobiletechnology synchronization requirements

MBSFN: Multimedia Broadcast Single Frequency Network; CoMP: Coordinated Multi-Point; eICIC: Enhanced Inter-Cell Interference Coordination; CA: Carrier Aggregation , MIMO: Multiple Input Multiple Output

Current situation

7

• ETECSA advances in the process of digital transformation.

• In its development plan includes technologies such as LTE-Advanced.

• The transport network must evolve to withstand more precise requirements,

specifically in the performance of phase synchronism.

Objective: To propose a phase synchronization solution for the ETECSA transport

network, based on the requirements imposed by LTE-Advanced.

8

Adoption of synchronism

9

Transport network

11

PTP frequency profile G.8265.1

12

PTP phase profile G.8275.1

• Full on-path support.• Boundary Clocks on all transmission network elements.• SyncE through the entire transmission path for stability.

13

PTP phase profile G.8275.2

• Partial on-path support.• Compatible with the G.8265.1 profile.• No change in network hardware.• Simple and easy to deploy for all LTE architectures.

14

PTP over OTN

15

Phase Synchronization Proposal *

Use of a mixed solution to minimize investment costs and take advantage of the technology

already deployed.

• In the Backbone, the transport of the PTP synchronism will occur over the OTN network

(existing cards).

• In the aggregation network, profile G.8275.2 is proposed.

• Equipment and link redundancy should be planned as a high availability solution.

• Implement the functionalities of BC (Boundary Clock) in all the nodes that allow it.

• Careful management and compensation of network path asymmetry errors.

19

Phase Synchronization Proposal ***

Backbone DWDM/OTN

MetroNetwork

GM - A GM - B

BCBC BC

BC BC

BC

BC

BC

BC

eNodeB

eNodeB

eNodeB

eNodeB

BC

NO PTP NO PTP

PTP

NO PTP

eNodeB

BC

BC

Aggregation (Metro 1)

Antenna GPS Antenna GPS

BCBC

Aggregation(Metro 2)

Aggregation(Metro 3)

MetroNetwork

MetroNetwork

20

Conclusions

• The new functionalities of LTE-Advanced impose new requirements on the transportnetworks. Specifically, they demand high precision for the delivery of phasesynchronism to the eNodeBs.

• For ETECSA, which has transport networks where not all elements support PTP, amixed solution (PTP over OTN and G.8275.2) is the most attractive from a technicaland economic point of view.

• It is necessary to carry out the pertinent measurements (PDV, asymmetries, etc),which guarantee the correct performance of the network, according to the ITU-Trecommendations.

Phase synchronization proposal over the transport network for LTE-Advanced

21

Author: Eng. Claudia Carballo González

Transmission Planning Department, ETECSA