Uu Based Soft Synchronization (ERAN12.1 - 03)

eRAN
Uu based Soft Synchronization

Feature Parameter Description
Issue 03
Date 2018-01-22
HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2018. All rights reserved.
No part of this document may be reproduced or transmitted in any form or by any means without prior written
consent of Huawei Technologies Co., Ltd.
Trademarks and Permissions
and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.
All other trademarks and trade names mentioned in this document are the property of their respective
holders.
Notice
The purchased products, services and features are stipulated by the contract made between Huawei and the
customer. All or part of the products, services and features described in this document may not be within the
purchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information,
and recommendations in this document are provided "AS IS" without warranties, guarantees or
representations of any kind, either express or implied.
The information in this document is subject to change without notice. Every effort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute a warranty of any kind, express or implied.
Huawei Technologies Co., Ltd.

Address: Huawei Industrial Base
Bantian, Longgang
Shenzhen 518129
People's Republic of China
Website: http://www.huawei.com
Email: support@huawei.com
Issue 03 (2018-01-22) Huawei Proprietary and Confidential i

Copyright © Huawei Technologies Co., Ltd.
eRAN
Uu based Soft Synchronization Feature Parameter
Description Contents
Contents
1 About This Document.................................................................................................................. 1

1.1 Scope.............................................................................................................................................................................. 1
1.2 Intended Audience.......................................................................................................................................................... 1
1.3 Change History............................................................................................................................................................... 1
1.4 Differences Between eNodeB Types.............................................................................................................................. 3
2 Overview......................................................................................................................................... 4
2.1 Background.....................................................................................................................................................................4
2.2 Introduction.................................................................................................................................................................... 5
2.3 Benefits........................................................................................................................................................................... 5
2.4 Architecture.................................................................................................................................................................... 5
3 Technical Description...................................................................................................................7
3.1 Overview........................................................................................................................................................................ 7
3.2 Initial Synchronization................................................................................................................................................... 8
3.2.1 Determining the Synchronization Zone and eNodeB Pairs....................................................................................... 11
3.2.2 Collecting Time Differences Between Paired eNodeBs............................................................................................13
3.2.3 Adjusting the Time on Non-reference eNodeBs Based on the Time on the Reference eNodeB.............................. 16
3.3 Synchronization Tracing...............................................................................................................................................17
3.4 Synchronization Maintenance...................................................................................................................................... 17
3.5 Absolute Time Synchronization................................................................................................................................... 19
3.6 Restrictions of Uu-based Soft Synchronization on Multimode Base Stations............................................................. 19
4 Related Features...........................................................................................................................21
5 Network Impact........................................................................................................................... 23
6 Engineering Guidelines............................................................................................................. 24
6.1 When to Use................................................................................................................................................................. 24
6.2 Required Information................................................................................................................................................... 24
6.3 Planning........................................................................................................................................................................ 25
6.3.1 RF Planning............................................................................................................................................................... 25
6.3.2 Networking Planning................................................................................................................................................. 25
6.3.3 Hardware Planning.................................................................................................................................................... 25
6.4 Feature Deployment..................................................................................................................................................... 26
6.4.1 Process....................................................................................................................................................................... 26
Issue 03 (2018-01-22) Huawei Proprietary and Confidential ii

eRAN
Description Contents
6.4.2 Requirements............................................................................................................................................................. 26
6.4.3 Precautions.................................................................................................................................................................27
6.4.4 Data Preparation and Feature Activation...................................................................................................................27
6.4.4.1 Data Preparation..................................................................................................................................................... 28
6.4.4.2 Using the CME....................................................................................................................................................... 38
6.4.4.3 Using MML Commands......................................................................................................................................... 39
6.4.4.4 MML Command Examples.................................................................................................................................... 40
6.4.5 Activation Observation..............................................................................................................................................41
6.4.6 Deactivation...............................................................................................................................................................43
6.4.6.1 Using the CME....................................................................................................................................................... 43
6.4.6.2 Using MML Commands......................................................................................................................................... 43
6.4.6.3 MML Command Examples.................................................................................................................................... 43
6.4.7 Reconfiguration......................................................................................................................................................... 43
6.5 Performance Monitoring...............................................................................................................................................43
6.5.1 Time Difference Measurements Between eNodeBs in eNodeB Pairs.......................................................................44
6.5.2 Absolute Values of Average Time Difference Changes Between eNodeBs..............................................................44
6.5.3 Absolute Values of Average Time Differences Between eNodeBs........................................................................... 45
6.6 Parameter Optimization................................................................................................................................................ 45
6.7 Possible Issues.............................................................................................................................................................. 46
6.7.1 Related Alarms.......................................................................................................................................................... 46
6.7.2 Handling Exceptions on Message Reporting.............................................................................................................47
7 Parameters..................................................................................................................................... 49
8 Counters........................................................................................................................................ 58
9 Glossary......................................................................................................................................... 60
10 Reference Documents............................................................................................................... 61
Issue 03 (2018-01-22) Huawei Proprietary and Confidential iii

eRAN
Description 1 About This Document
1 About This Document
1.1 Scope
This document describes LOFD-080216 Uu based Soft Synchronization, including its
technical principles, related features, network impact, and engineering guidelines.
Feature compatibility with specific terminal models is not presented in this document. For
compatibility information, contact Huawei engineers.
Any parameters, alarms, counters, or managed objects (MOs) described herein apply only to
the corresponding software release. For future software releases, refer to the corresponding
updated product documentation.
This document applies only to LTE FDD. Any "LTE" in this document refers to LTE FDD,
and "eNodeB" refers to LTE FDD eNodeB.
1.2 Intended Audience

This document is intended for personnel who:
l Need to understand the features described herein

l Work with Huawei products
1.3 Change History

This section provides information about the changes in different document versions. There are
two types of changes:
l Feature change
Changes in features and parameters of a specified version as well as the affected entities
l Editorial change
Changes in wording or addition of information and any related parameters affected by
editorial changes. Editorial change does not specify the affected entities.
Issue 03 (2018-01-22) Huawei Proprietary and Confidential 1

eRAN
eRAN12.1 03 (2018-01-22)
This issue includes the following changes.
Change Change Description Parameter Affected

Type Change Entity
Feature None None N/A

change
Editorial Moved LOFD-001031 Extended None N/A

change CP from mutually exclusive
features to impacted features. For
details, see 4 Related Features.
eRAN12.1 02 (2017-04-26)
This issue includes the following changes.

Type Change Entity

change
Editorial Revised descriptions in Mutually None N/A

change Exclusive Features in 4 Related
Features.
eRAN12.1 01 (2017-03-08)
This issue does not include any changes.
eRAN12.1 Draft A (2016-12-30)

Draft A (2016-12-30) of eRAN12.1 introduces the following changes to Issue 01
(2016-03-07) of eRAN11.1.

Type Change Entity

change
Editorial Revised descriptions in this None N/A

change document.

eRAN
1.4 Differences Between eNodeB Types

Both macro and LampSite base stations support this feature.

eRAN
Description 2 Overview
2 Overview
2.1 Background
Many LTE features pose high requirements on time synchronization.
l LOFD-070208 Coordinated Scheduling based Power Control
In most cases, neighboring evolved universal terrestrial radio access network (E-
UTRAN) cells on the same frequency interfere with one another. To reduce the
interference, the transmit power for downlink (DL) channels can be coordinated to
increase the signal to interference plus noise ratio (SINR) of cell edge user equipment
(UEs) and therefore improve network performance. LOFD-070208 Coordinated
Scheduling based Power Control is introduced to coordinate TTI-specific transmit power
configurations in individual cells. It reduces inter-cell interference based on
collaboration between scheduling and power control. (TTI is short for transmission time
interval.) This feature requires time synchronization between eNodeBs.
l TDM eICIC
In an intra-frequency heterogeneous network (HetNet), micro eNodeBs supplement
network coverage and increase network capacity. Macro cells and micro cells cause
interference on each other. TDM eICIC decreases interference between macro cells and
micro cells by coordinating available time-domain resources of neighboring cells,
thereby increasing downlink performance and throughput of CEUs in an intra-frequency
HetNet. TDM and eICIC are short for time division multiplexing and enhanced inter-cell
interference coordination, respectively. TDM eICIC requires time synchronization
between macro cells and micro cells involved in interference coordination.
l LOFD-070220 eMBMS Phase 1 based on Centralized MCE Architecture
This feature enables one data source to transmit data to multiple UEs based on network
resource sharing. eMBMS is short for evolved multimedia broadcast/multicast service.
eMBMS improves the resource utilization rate and enables multimedia services to be
broadcast in high data rates. eMBMS requires time synchronization between eNodeBs.
To support eMBMS in eNodeBs within 3 km from each other in the Multimedia
Broadcast multicast service Single Frequency Network (MBSFN) area, the time
difference between eNodeBs must be less than 3 microseconds (µs).
l LAOFD-080201 Inter-eNodeB CA based on Relaxed backhaul
According to 3GPP specifications, LTE-Advanced intends to provide a service data rate
as high as 1 Gbit/s in the downlink. Because frequency spectrums are in shortage and

eRAN
spectrum resources granted to operators are non-contiguous, a single frequency band can
hardly provide the bandwidths required by LTE-Advanced. Therefore, 3GPP TR 36.913
Release 10 introduced carrier aggregation (CA) to provide a maximum of 100 MHz
bandwidth by aggregating multiple contiguous or non-contiguous carriers. In addition,
CA improves the usage of scattered frequency spectrums, especially in refarming
scenarios. LAOFD-080201 Inter-eNodeB CA based on Relaxed backhaul requires time
synchronization between eNodeBs with CA implemented. Specifically, downlink CA
requires the time synchronization accuracy of ± 1.5 μs.
Currently, eNodeBs support features related to time synchronization such as LBFD-00300503

GPS Synchronization and LOFD-00301302 IEEE1588 V2 Clock Synchronization.
LBFD-00300503 GPS Synchronization requires GPS, which increases hardware deployment
costs. LOFD-00301302 IEEE1588 V2 Clock Synchronization requires transport devices to
support the IEEE1588 V2 protocol, which may require transmission network reconstruction.
Compared with the preceding two features, LOFD-080216 Uu based Soft Synchronization
supports time synchronization at lower cost without the need for transmission network
reconstruction.
2.2 Introduction
Uu-based soft synchronization achieves time synchronization between eNodeBs by adjusting
time differences between the eNodeBs based on software measurement results. In Uu-based
soft synchronization, the time difference between two neighboring eNodeBs can be obtained
during physical random access channel (PRACH) measurements initiated by CEUs or UEs in
inter-eNodeB handovers. A centralized control node collects all time differences reported by
eNodeBs within the area where the coordination feature is applied. This area is known as the
Uu-based soft synchronization zone and is also referred to as synchronization zone in this
document. The centralized control node calculates the time adjustment quantity of each
eNodeB against the reference eNodeB and adjusts the time of all eNodeBs. In this way, all
eNodeBs within the synchronization zone achieve time synchronization with the reference
eNodeB. Before Uu-based soft synchronization, eNodeBs need to achieve frequency
synchronization based on synchronous Ethernet. Time synchronization must be performed on
the basis of frequency synchronization. Frequency synchronization provides a basis for time
holdover of eNodeBs.
2.3 Benefits
l The Uu based Soft Synchronization feature provides time synchronization accuracy of
less than or equal to 3 µs, which satisfies the demanding time synchronization
requirements of coordination features such as TDM eICIC and CSPC.
l In scenarios with synchronous Ethernet deployed, compared with LBFD-00300503 GPS
Synchronization and LOFD-00301302 IEEE1588 V2 Clock Synchronization, the Uu
based Soft Synchronization feature supports time synchronization at lower cost without
the need for transmission network reconstruction.
2.4 Architecture
Figure 2-1 shows the network architecture for deploying LOFD-080216 Uu based Soft
Synchronization. The architecture includes the following network elements (NEs): eNodeBs
(one eNodeB functions as the reference eNodeB), a centralized control node (the

eRAN
eCoordinator, which is abbreviated as eCo in the figure), and UEs in inter-eNodeB handovers
or CEUs under the neighboring eNodeBs.
Figure 2-1 Network architecture for deploying the Uu based Software Synchronization
feature
l Reference eNodeB
The reference eNodeB works as the time synchronization source in a synchronization
zone. Other eNodeBs maintain time synchronization with the reference eNodeB.
Generally, an eNodeB located at the center of the synchronization zone and equipped
with the GPS is selected as the reference eNodeB.
l Centralized control node
A centralized control node is the control center for deploying this feature. A centralized
control node delivers configuration commands to eNodeBs, collects time differences
between eNodeBs, and calculates time adjustment quantity for each eNodeB. Currently,
the eCoordinator works as the centralized control node.
l UEs in inter-eNodeB handovers or CEUs under neighboring eNodeBs
A UE in an inter-eNodeB handover: The UE assists the serving eNodeB in collecting the
time difference between the eNodeB and its neighboring eNodeB.
A CEU under a neighboring eNodeB: The UE assists the serving eNodeB in collecting
the time difference between the eNodeB and its neighboring eNodeB based on random
access requests to the neighboring eNodeB.

eRAN
Description 3 Technical Description
3 Technical Description
3.1 Overview
The overall procedure of Uu-based soft synchronization includes initial synchronization and
synchronization tracing.
Initial synchronization includes the following three steps:
1. Determining the synchronization zone and neighboring eNodeB pairs
2. Collecting time differences between each pair of eNodeBs
3. Adjusting the time on non-reference eNodeBs based on the time on the reference
eNodeB
Synchronization tracing includes the following two steps:
1. Collecting time differences between each pair of eNodeBs
2. Adjusting the time on non-reference eNodeBs based on the time on the reference
eNodeB
After initial synchronization and synchronization tracing are complete, the eNodeBs enter the
synchronization maintenance state to maintain time synchronization accuracy.

eRAN
Figure 3-1 Procedure for Uu-based soft synchronization
3.2 Initial Synchronization

After LOFD-080216 Uu based Soft Synchronization is enabled, a non-reference eNodeB
performs initial synchronization to generally adjust the time difference between the eNodeB
and the reference eNodeB. General adjustment is performed once only.
The methods for measuring time differences between eNodeBs in eNodeB pairs differ
depending on whether a UE is a CEU or a UE involved in inter-eNodeB handovers.
l Figure 3-2 shows the procedure that UEs involved in inter-eNodeB handovers measure
time differences between eNodeBs in eNodeB pairs.

eRAN
Figure 3-2 Time difference measurement performed by UEs involved in inter-eNodeB

handovers
a. The source eNodeB sends a Handover Request message to the target eNodeB.
Then, the source eNodeB sends a Random Access Command to a UE. The UE
sends a random access preamble to the source eNodeB, based on which the source
eNodeB obtains the delay in transmitting the preamble from the UE to the source
eNodeB. The delay is recorded as Tpa1.
b. After receiving the Handover Request message, the target eNodeB sends the source
eNodeB a Handover Request Acknowledgement message. The source eNodeB
enables the preamble blind detection and receive function and sends a handover
command to the UE.
c. The UE sends a random access preamble to the target eNodeB. The source eNodeB
blindly detects the preamble sent by the UE and obtains the delay in transmitting
the preamble from the UE to the target eNodeB. The delay is recorded as Tneigh.

eRAN
NOTE
If the source cell for an inter-eNodeB handover is an SFN cell whose physical cells are
served by a single eNodeB, the physical cell where the handover is initiated on the source
eNodeB must be the physical cell where the blind detection is initiated. Otherwise, the
measurement fails.
d. The target eNodeB detects the preamble sent by the UE and obtains the delay in
transmitting the preamble from the UE to the target eNodeB. The delay is recorded
as Taccess. The target eNodeB sends a Random Access Command message to the
UE. The UE initiates a random access preamble to the target eNodeB. The target
eNodeB obtains the delay in transmitting the preamble from the UE to the target
eNodeB. The delay is recorded as Tpa2.
NOTE
If the target cell for an inter-eNodeB handover is an SFN cell whose physical cells are served
by a single eNodeB, the target physical cell served by the target eNodeB must be the blindly
detected physical cell. Otherwise, the measurement fails.
e. The target eNodeB sends the UE Context Release message to the source eNodeB.
After receiving the message, the source eNodeB stops preamble blind detection.
f. The source eNodeB calculates the time difference based on the following formula:
Tdif = (Taccess – Tneigh) - (Tpa1 - Tpa2). In the formula, "(Tpa1 - Tpa2)"
indicates the difference between the delays in transmitting UE's signals to the two
eNodeBs.
l Figure 3-3 shows the procedures that CEUs measure time differences between eNodeBs
in eNodeB pairs.
Figure 3-3 Time differences measured by CEUs performing random accesses
a. The source eNodeB sends a Blind Detect Request message to the neighboring
eNodeB. The neighboring eNodeB enables the preamble blind detection and receive
function for preambles sent by a CEU and sends a Blind Detect Response message
to the source eNodeB.

eRAN
NOTE
If physical cells of an SFN cell are served by a single eNodeB, this SFN cell supports blind
detection only when the serving eNodeB serves the SFN cell and the neighboring eNodeB
serves non-SFN cells.
b. The serving eNodeB sends a Random Access Request message to the UE. The UE
sends random access signals to the serving eNodeB. The neighboring eNodeB
blindly detects the preambles sent by the UE and obtains Tneigh, and then stops
blind detection. The neighboring eNodeB sends the serving eNodeB the Blind
Detect Result message, including the obtained Tneigh.
c. The serving eNodeB detects the preamble and obtains the Taccess. The time
difference between the serving eNodeB and the neighboring eNodeB (Tdif) is the
difference between Taccess and Tneigh. The time difference is measured in the unit
of Ts.
NOTE
Compared with time differences measured by UEs involved in inter-eNodeB handovers, time differences
measured by CEUs initiating random accesses may induce errors because the transmission delay
differences between the CEU to the two eNodeBs cannot be obtained. Therefore, if time differences
measured by both types of UEs are available, you are advised to preferentially use the time difference
measured by UEs involved in inter-eNodeB handovers.
3.2.1 Determining the Synchronization Zone and eNodeB Pairs

Before enabling coordination features requiring inter-eNodeB time synchronization, such as
eMBMS and CSPC, ensure that the area to be enabled with coordinated features is the Uu-
based soft synchronization zone (also referred to as synchronization zone in this document).
Then, select an eNodeB as the reference eNodeB in the synchronization zone. Configure two
neighboring eNodeBs as an eNodeB pair. To increase reliability, a primary and a secondary
reference eNodeBs can be selected.
Figure 3-4 shows a Uu-based soft synchronization zone. In the figure, one hexagon refers to
one eNodeB (a cell in live networks). eNodeB 1 is the reference eNodeB. Two neighboring
eNodeBs in different colors form a pair. The eNodeBs in amber that are neighboring eNodeBs
of the reference eNodeB belong to synchronization level-1. The eNodeBs in purple that are
neighboring eNodeBs of the eNodeBs in synchronization level-1 belong to the
synchronization level-2, and so forth. Synchronization level-1 eNodeB pairs include 1-2, 1-3,
1-4, …, and 1-7. Synchronization level-2 eNodeB pairs include 2-8, 2-9, 2-10, 3-11, 4-12,
4-13, …, and 7-19. Synchronization level-3 eNodeB pairs include 8-20.

eRAN
Figure 3-4 Uu-based soft synchronization zone
NOTE
l One eCoordinator supports a maximum of 256 synchronization zones and a maximum of 5000
eNodeBs for Uu-based soft synchronization.
l eNodeB pairs are automatically added and then can be manually changed.
The eCoordinator adds synchronization zones based on the execution of the ADD
AISSZONE command. Parameters AISSZONE.FrequencyBand,
AISSZONE.DLFrequency, and AISSZONE.DLBandWidth are used to verify whether an
eNodeB to be added belongs to the synchronization zone. If all of the parameters
CELL.FreqBand, CELL.DlEarfcn, and CELL.DlBandwidth of any cell under the eNodeB
have values different from the parameters AISSZONE.FrequencyBand,
AISSZONE.DLFrequency, and AISSZONE.DLBandWidth, the eNodeB cannot be added to
the synchronization zone.
The eCoordinator adds eNodeBs to the synchronization zone based on the execution of the
ADD ENBAISS command. You can specify a primary reference eNodeB and a secondary
reference eNodeB by running the ADD ENBAISS command twice with the
ENBAISS.BaseStationType parameter set to PRIBASE and BAKBASE, respectively. You
can also specify common eNodeBs by running the ADD ENBAISS command with the
ENBAISS.BaseStationType parameter set to NORMALBASE. If the primary reference
eNodeB experiences exceptions (such as the synchronous Ethernet is faulty or the eNodeB is
powered off), the secondary reference eNodeB functions as the reference clock source.
The eCoordinator activates the automatic eNodeB pairing calculation function based on the
execution of the ACT AISSNENBCALC command. After the automatic calculation, you can
manually change some eNodeB pairs by running the RMV AISSNENB or ADD AISSNENB
command.
Collecting information about eNodeB pairs

eRAN
The eCoordinator starts to collect information about eNodeB pairs after the synchronization
zone is activated and the automatic eNodeB pairing calculation function is enabled (or the
eNodeB pairs are manually added). As shown in Figure 3-5, the eCoordinator sends an
AISS_INFO_REQ message to an eNodeB. The eNodeB sends the eCoordinator an
AISS_INFO_RSP message. This message includes IEs AISS eNB Info and Neighber eNB
List, which carry the basic information about the eNodeB and intra-frequency neighboring
eNodeB list, respectively.
Figure 3-5 Collecting information about eNodeB pairs
3.2.2 Collecting Time Differences Between Paired eNodeBs

When a UE is handed over between two paired eNodeBs, both eNodeBs detect the random
access preamble sent by the UE simultaneously. Each eNodeB records the time when the
random access preamble is detected, and the source eNodeB then calculates the time
differences based on the delays in transmitting the UE's preambles to the two eNodeBs.
The ADD AISSZONE command can be executed on the eCoordinator to specify parameters
related to Uu-based soft synchronization. The AISSZONE.MeasureTime parameter specifies
the start time for measuring time differences between each two paired eNodeBs in a
synchronization zone. The AISSZONE.MeasureLast parameter specifies the duration during
which time differences between each two paired eNodeBs in a synchronization zone are
measured. The AISSZONE.DetectAvoidSwitch parameter specifies whether preamble blind
detection can be performed during data transmission over PRACH frequency resources. If this
parameter is set to OFF(Off), preamble blind detection cannot be performed during data
transmission over PRACH frequency resources. In this case, uplink throughput is not affected,
but the preamble blind detection success rate may decrease. If this parameter is set to
ON(On), preamble blind detection can be performed during data transmission over PRACH
frequency resources. In this case, uplink throughput decreases slightly, and the preamble blind
detection success rate increases. This parameter is set to OFF(Off) by default. You are
advised to set this parameter to ON(On) if the preamble blind detection success rate is low.
However, do not set this parameter to ON(On) if the system bandwidth is less than or equal to
5 MHz.
The time differences between paired eNodeBs are measured based on eNodeB pairs in
ascending order of synchronization levels. The message flow between the eCoordinator and
eNodeBs during time difference measurement is as follows:
1. Starting time difference measurements

eRAN
As shown in Figure 3-6, time difference measurement starts if either of the following
conditions is met:
l The time on the eCoordinator approaches the time specified by the
AISSZONE.MeasureTime parameter.
l The synchronization state of the synchronous Ethernet of the eNodeB restores to normal.
The eCoordinator delivers AISS_MEAS_START_REQ messages to the eNodeBs, instructing
each eNodeB to measure the time difference with its neighboring eNodeB in each eNodeB
pair. An AISS_MEAS_START_REQ message includes IEs AISS Measure Type, AISS Cell
Para, and AISS Measure Para. The IE AISS Measure Type indicates the UE types in intra-
frequency neighboring eNodeBs involved in time difference measurements, including CEUs
in inter-eNodeB handovers, CEUs, and UEs in inter-eNodeB handovers.
l If both a local eNodeB and its neighboring eNodeB transmit power at average strength,
the IE AISS Measure Type is automatically set to the value indicating CEUs in inter-
eNodeB handovers.
l If a local eNodeB transmits power at average strength and its neighboring eNodeB
transmits power in low strength, the IE AISS Measure Type is automatically set to the
value indicating CEUs.
l If a local eNodeB transmits power at low strength and its neighboring eNodeB transmits
power at average strength, the IE AISS Measure Type is automatically set to the value
indicating UEs in inter-eNodeB handovers.
The IE AISS Measure Para includes parameters Mea Last Time and Rsrp Shreshold, which
indicate the time difference measurement duration and RSRP threshold, respectively. After
starting time difference measurements, the eNodeBs send the eCoordinator the
AISS_MEAS_START_RSP messages, indicating whether the time difference measurements
are successful.
NOTE
Only CEUs that newly access cells trigger time difference measurements.
Figure 3-6 Starting time difference measurements
2. Updating parameters related to time difference measurements

The eCoordinator sends eNodeBs AISS_MEAS_PARA_UPT messages including the IE AISS
Measure Para UPT, instructing eNodeBs to update parameters related to time difference

eRAN
measurements. The IE AISS Measure Para UPT is used to update parameters Neighber eNB
ID (indicating ID of a neighboring eNodeB), Ho Rsrp Shreshold (indicating RSRP threshold
for inter-eNodeB handovers), and Ce Rsrp Shreshold (indicating RSRP threshold received
by CEUs).
Figure 3-7 Updating parameters related to time difference measurements
3. Sending time difference measurement reports

After time difference measurements, eNodeBs send the eCoordinator the AISS_
MEASURE_RPT messages including the IE AISS Measure Report. The IE AISS Measure
Report includes the time difference (TimeDif) and transmission delay (Tp Dif) between a
local eNodeB and its neighboring eNodeB. TimeDif is calculated by (Taccess - Tneigh), and
Tp Dif is calculated by (Tpa1 - Tpa2).
Figure 3-8 Sending time difference measurement reports
4. Stopping time difference measurements

After the time on some eNodeBs approaches the time specified by the
AISSZONE.MeasureLast parameter, the eCoordinator delivers AISS_MEAS_STOP_REQ
messages, including the IE AISS Measure Stop Type, to these eNodeBs, instructing these
eNodeBs to stop time difference measurements. The IE AISS Measure Stop Type includes the
list of neighboring eNodeBs (specified by the Neighber eNB List parameter) that are required
to stop time difference measurements.

eRAN
Figure 3-9 Stopping time difference measurements
3.2.3 Adjusting the Time on Non-reference eNodeBs Based on the

Time on the Reference eNodeB
After collecting time differences between paired eNodeBs in a synchronization zone, the
eCoordinator calculates the time differences between each eNodeB and the reference eNodeB,
and instructs all eNodeBs to adjust the time at the same time.
When the time on the eCoordinator approaches the time specified by the
AISSZONE.AdjustTime parameter set in the ADD AISSZONE command, the eCoordinator
delivers eNodeBs AISS_TIME_ADJUST_REQ messages including the IE AISS Time Adjust,
instructing each eNodeB to adjust the time and maintain time synchronization with the
reference eNodeB, as shown in Figure 3-10.
NOTE
If the clock state becomes abnormal during time difference measurements, time difference
measurements stop even if the clock state restores to normal, and subsequent time difference adjustment
cannot be performed. A time difference adjustment can be performed only if the previous time
difference measurement is successful and the clock state is normal after the time difference
measurement.
Figure 3-10 Adjusting time differences

eRAN
3.3 Synchronization Tracing

To maintain the time synchronization accuracy of Uu-based soft synchronization, eNodeBs
perform periodic fine-tuning on time differences between eNodeBs after initial
synchronization. Procedures for synchronization tracing are the same as those for initial
synchronization, except for synchronization zone determination and eNodeB pair
determination.
3.4 Synchronization Maintenance

The synchronous Ethernet clock must be configured before Uu-based soft synchronization is
enabled, so that frequency synchronization provided by the synchronous Ethernet clock serves
as the basis for time synchronization. The eNodeB enters the synchronization tracing state
after initial synchronization. Highly reliable and high-precision frequency synchronization
provided by synchronous Ethernet maintains time synchronization accuracy during
synchronization tracing.
The AISS.FLAG parameter set in the SET AISS command specifies whether to enable Uu-
based soft synchronization on an eNodeB. The synchronous Ethernet clock can be configured
on an eNodeB by running the ADD SYNCETH command. The working mode of the
reference clock source and the clock synchronization mode of an eNodeB can be set by
running commands SET CLKMODE and SET CLKSYNCMODE, respectively.
eNodeBs report synchronization status to the eCoordinator, and the eCoordinator performs
different operations based on different synchronization status. Synchronization status
reporting involves starting, sending, and stopping Uu-based soft synchronization status
reports.
1. During the starting of AISS synchronization status reporting shown in Figure 3-11, the
eCoordinator sends eNodeBs the AISS_STATE_START_REQ messages, and then each
eNodeB sends the eCoordinator an AISS_STATE_START_RSP message.
Figure 3-11 Starting Uu-based soft synchronization status reporting
2. During the sending of AISS synchronization status reporting shown in Figure 3-12, each
eNodeB sends the eCoordinator an AISS_ STATE_RTP message including the IE

eRAN
AissState that indicates the synchronization status. This message indicates whether the
frequency synchronization or time synchronization of the eNodeB is in the normal state.
Figure 3-12 Sending AISS synchronization status reporting
3. During the stopping of AISS synchronization status reports shown in Figure 3-13, the
eCoordinator sends an AISS_STATE_STOP_REQ message to the eNodeB that has sent
synchronization status reports, and then the eNodeB sends an AISS_STATE_STOP_RSP
message to the eCoordinator.
Figure 3-13 Stopping AISS synchronization status reports
When the synchronization status changes, the current synchronization status will be reported
to the following features depending on time synchronization provided by Uu-based soft
synchronization:
l LAOFD-080201 Inter-eNodeB CA based on Relaxed backhaul
l LOFD-070208 Coordinated Scheduling based Power Control
l LOFD-081219 Inter-eNodeB VoLTE CoMP
l LBFD-002022 Static Inter-Cell Interference Coordination

eRAN
3.5 Absolute Time Synchronization

Uu-based soft synchronization supports only the synchronization between frame phases and
frame numbers delivered by eNodeBs over the Uu interfaces. To achieve absolute time
synchronization between eNodeBs and the Universal Time Coordinate (UTC) time, the GPS
and Network Time Protocol (NTP) must be used together with Uu-based soft synchronization.
NTP supports timing between eNodeBs and the U2000 in network operation and maintenance
(O&M). For details, see Time Management Feature Parameter Description. Both GPS and
NTP support synchronization with the UTC time. However, the NTP time is of lower
precision and differs from the GPS time, which requires time calibration.
The procedure for absolute time synchronization is as follows:
1. An eNodeB within the synchronization zone with the GPS (or IEEE1588 V2 clock)
installed is termed as the GPS eNodeB. The GPS eNodeB achieves time synchronization
with the UTC time obtained by the GPS.
2. eNodeBs within the synchronization zone with the NTP clients installed is termed as the
NTP eNodeBs. The NTP eNodeBs achieve time synchronization with the NTP-obtained
UTC time. Compared with the GPS-obtained UTC time, the NTP-obtained UTC time
has the time difference T1.
3. Uu-based soft synchronization is enabled on eNodeBs within the synchronization zone.
Frame phases and frame numbers delivered by the GPS eNodeB and frame phases and
frame numbers delivered by the NTP eNodeBs are synchronized, respectively.
4. The GPS eNodeB calculates the time difference T1 and calibrates the time difference,
maintaining time synchronization between the NTP-obtained UTC time and the GPS-
obtained UTC time.
The methods for configuring the GPS and NTP are as follows:
l GPS: Configure the GPS on an eNodeB by running the ADD GPS command. Set the
working mode of the reference clock source and the clock synchronization mode of the
eNodeB by running commands SET CLKMODE and SET CLKSYNCMODE,
respectively.
l NTP: Set the reference clock source to NTP by running the SET TIMESRC command.
Set the IP address, port number, timing period, and encryption mode of the NTP server
by running the ADD NTPC command. Set parameters related to the primary NTP server
by running the SET MASTERNTPS command.
NOTE
l Set the SYNCCYCLE parameter in the ADD NTPC command to a value less than 60 minutes
to decrease the time differences between eNodeBs.
l The difference between the NTP time and the UTC time must be less than 4 seconds, and the
NTP server must connect to the GPS.
l The reference clock source of the synchronous Ethernet must be GPS.
3.6 Restrictions of Uu-based Soft Synchronization on

Multimode Base Stations
The Uu-based Soft Synchronization feature supports Uu-based soft synchronization between
multimode base stations:

eRAN
l If an RRU supports both UMTS and LTE or supports both GSM and LTE, only the major
RAT for clock mutual lock (GSM or LTE) can perform Uu-based soft synchronization,
and GSM and LTE cannot simultaneously perform Uu-based soft synchronization. The
major RAT for clock mutual lock can be queried by running the DSP
CLKMUTUALLOCK command. If the multimode base station is equipped with a
GTMU, only GSM can perform Uu-based soft synchronization and LTE cannot.
l If an RRU does not support both UMTS and LTE or both GSM and LTE, both GSM and
LTE can simultaneously perform Uu-based soft synchronization.
l In co-MPT multimode base stations, only GSM or LTE can perform Uu-based soft
synchronization separately, and GSM and LTE cannot simultaneously perform Uu-based
soft synchronization. After LTE performs Uu-based soft synchronization, GSM supports
automatic time synchronization. After GSM performs Uu-based soft synchronization,
LTE does not support automatic time synchronization.
l In co-MPT LTE FDD/LTE TDD dual-mode base stations, LTE FDD does not support
Uu-based soft synchronization.
Based on the preceding restrictions, whether a RAT on a multimode base station can perform
Uu-based soft synchronization can be controlled based on the AISS.STANDARD parameter
value.
Table 3-1 Uu-based soft synchronization supported by multimode base stations

Mult Multimod Main Main Control Main Control Supported
imo e Scenario Control Board Used by Board Used by LTE
de Board UMTS by LTE
Base Used by
Stati GSM
ons
GL Separate- GTMU N/A LMPT/UMPT No

MPT
UMPT N/A LMPT/UMPT Yes
Co-MPT UMPT N/A UMPT Yes
GUL Separate- GTMU WMPT/UMPT LMPT/UMPT No

MPT
UMPT WMPT/UMPT LMPT/UMPT Yes
Co-MPT UMPT UMPT UMPT Yes
UL Separate- N/A WMPT LMPT/UMPT Yes

MPT
N/A UMPT LMPT/UMPT Yes
Co-MPT N/A UMPT UMPT Yes

eRAN
Description 4 Related Features
4 Related Features
Prerequisite Features
Feature ID Feature Name Description
LOFD-00301301 Synchronization with The Uu-based soft synchronization

Ethernet (ITU-T G.8261) accuracy is dependent on
synchronization reliability of the
synchronous Ethernet.
Mutually Exclusive Features

LBFD-00300504 Synchronization with BITS LOFD-080216 Uu based Soft

Synchronization cannot be enabled
LBFD-00300505 Synchronization with 1PPS together with any of these features.
LBFD-00300506 Synchronization with
E1/T1
LOFD-00301302 IEEE1588 V2 Clock

Synchronization
LOFD-00301303 Clock over IP (Huawei

proprietary)
LOFD-121212 eNodeB Supporting

1588v2 ATR
LOFD-001007 High Speed Mobility These features do not support the frame
format on the PRACH. LOFD-080216
LOFD-001008 Ultra High Speed Mobility Uu based Soft Synchronization cannot
LOFD-001009 Extended Cell Access be enabled together with any of these
Radius features.

eRAN
Description 4 Related Features
Impacted Features
LOFD-001031 Extended CP The time synchronization accuracy of

Uu-based soft synchronization
decreases in the extended CP case.

eRAN
Description 5 Network Impact
5 Network Impact
System Capacity
No impact.
Network Performance
If the time differences between eNodeBs in eNodeB pairs are large during initial
synchronization, the time adjustment step is also large. As a result, services are interrupted for
several seconds during initial synchronization. Because initial synchronization is performed
once only after LOFD-080216 Uu based Soft Synchronization is enabled and performed when
traffic is light (for example, 02:00 during the night), initial synchronization generally has little
impact on services. Synchronization tracing has no impact on services.
Consider that Uu-based soft synchronization is enabled in the LTE RAT in a co-SDR or CPRI
MUX networking multimode base station. If the time differences between eNodeBs in
eNodeB pairs are large during initial synchronization, the time adjustment step is also large,
and services served by other RATs are interrupted for several seconds.

eRAN
Description 6 Engineering Guidelines
6 Engineering Guidelines
6.1 When to Use

Enable LOFD-080216 Uu based Soft Synchronization when all of the following conditions
are met:
l Related coordination features (listed in 4 Related Features) need to be deployed and
these features require eNodeBs to support time synchronization.
l Transmission devices support the synchronous Ethernet clock.
l Compared with LBFD-00300503 GPS Synchronization and LOFD-00301302 IEEE1588
V2 Clock Synchronization, operators want to deploy time synchronization at low cost
without the need for transmission network reconstruction.
6.2 Required Information

1. Determine the synchronization zone: Determine an area for deploying coordination
features (such as eMBMS and TDM eICIC) before enabling these features. This area is
called the synchronization zone.
2. Analyze traffic volume in the synchronization zone: Analyze the distribution of average
traffic volume in a week in different time spans within the synchronization zone.
Determine the time to collect time differences between eNodeBs in eNodeB pairs and
the time to adjust eNodeB time. Set the time to collect time differences to the time when
the traffic volume is neither too large nor too small. Because event A3 measurements are
required in time difference measurements and it takes 100 ms to perform preamble blind
detection in each event A3 measurement, the time to collect time differences cannot be
set to the peak traffic volume time to decrease impacts on services. In addition, time
difference measurements cannot be performed if the number of UEs in inter-eNodeB
handovers is too small. Therefore, the time to collect time differences cannot be set to
the time when the traffic volume is too small. You are advised to enable the eNodeB to
perform time difference adjustment when traffic volume is light (for example, 02:00 in
the early morning) in order to decrease impacts on services.
3. Analyze the stability of synchronization maintenance in synchronous Ethernet: Only
time difference collection is activated in the synchronization zone, and time difference
adjustment is not activated. Set the AISSZONE.MeasurePeriod parameter to 10 in the
unit of day to check the stability of synchronization maintenance between eNodeBs and

eRAN
the fluctuation of time differences between eNodeBs in a week. More than 99% changes
in time differences between eNodeBs must be less than 3 µs.
4. Collect alarms reported by eNodeBs. First clear the following alarms if any is reported:
– ALM-25880 Ethernet Link Fault: This alarm indicates the frequency of
transmission link interruption in a single eNodeB and can be cleared by
troubleshooting transmission link faults.
– ALM-26262 External Clock Reference Problem: This alarm indicates how frequent
the reference clock source of a single eNodeB is unlocked and can be cleared by
troubleshooting clock link faults.
– ALM-25621 Power Supply DC Output Out of Range, ALM-25622 Mains Input Out
of Range, and ALM-25626 Power Module Abnormal: These alarms indicate how
frequent a single eNodeB is powered off and can be cleared by troubleshooting
power module faults.
– (Optional) ALM-26266 Time Synchronization Failure: This alarm indicates that a
single eNodeB fails NTP timing and can be cleared by troubleshooting NTP clock
link faults.
6.3 Planning
6.3.1 RF Planning
This feature supports the deployment of Huawei eNodeBs providing continuous intra-
frequency coverage and does not support mixed deployment of Huawei eNodeBs and non-
Huawei eNodeBs.
6.3.2 Networking Planning

l The eCoordinator is functioning normally. The Se interfaces between the eCoordinator
and eNodeBs are correctly configured and the Se links are in the normal state.
NOTE
For details about the Se interface, see IP Transmission Feature Parameter Description. For details
about how to configure the Se interface, see IP eRAN Engineering Guide Feature Parameter
Description.
l All eNodeBs within a synchronization zone must be configured with the same
synchronous Ethernet clock source and all transport devices within the synchronization
zone support synchronous Ethernet.
l Transmission devices must support the synchronization status message (SSM) protocol
defined by ITU-T G.8264.
l The synchronization accuracy of the clock in the upper level of the synchronous Ethernet
installed on eNodeBs must be better than 16 ppb.
l Distances between eNodeBs within a synchronization zone must be less than 15 km.
6.3.3 Hardware Planning

l ECO6910 is required.
l eNodeBs must meet the following requirement:
3900 or 5900 series macro eNodeBs with the baseband processing unit being LBBPd or
UBBP and the main control board being LMPT or UMPT

eRAN
NOTE
If a 3900 or 5900 series macro eNodeB is equipped with the LBBPd or UBBPd and serves 4R and
8R cells, the PRACH configurations of one cell cannot overlap the PRACH configurations of
another cell in the time domain. This requires that the eNodeB-level parameter
PrachTimeStagSwitch be set to ON and cell-level parameter PrachConfigIndexCfgInd be set to
NOT_CFG.
l An NTP server and GPS must be installed when eMBMS is required. In this case, the
GPS clock must be selected as the reference clock for synchronous Ethernet.
6.4 Feature Deployment
6.4.1 Process
Step 1 Deploy the eCoordinator. The Se interfaces between the eCoordinator and eNodeBs are
correctly configured and the Se links are in the normal state.
NOTE
For details about the Se interface, see IP Transmission Feature Parameter Description. For details about
how to configure the Se interface, see IP eRAN Engineering Guide Feature Parameter Description.
Step 2 Enable Uu-based soft synchronization on eNodeBs, configure the synchronous Ethernet clock
for the eNodeBs, and configure information about longitudes and latitudes of the eNodeBs.
Step 3 Configure X2 interfaces between eNodeBs.
Step 4 On the eCoordinator, configure a synchronization zone, add eNodeBs to the synchronization
zone, and configure a reference eNodeB.
Step 5 Install GPS on one of the eNodeBs in the synchronization zone where absolute time
synchronization is required, and then install NTP clients on all eNodeBs in the
synchronization zone. Synchronize the NTP time on all eNodeBs with the time on the
eNodeB with GPS installed.
Step 6 Activate the synchronization zone on the eCoordinator and activate the automatic eNodeB
pairing calculation function.
----End
6.4.2 Requirements
Other Features
The prerequisite features of LOFD-080216 Uu based Soft Synchronization must be enabled
before this feature is enabled. For details, see 4 Related Features.
Hardware
For details, see 6.3.3 Hardware Planning.

eRAN
License
Feature ID Feature Model License NE Sales Unit
Name Control Item
LOFD-080216 Uu based LEC2AI Uu based Soft eCoordi per eNodeB

Soft SS01 Synchronizatio nator
Synchronizat n(LTE FDD)
ion (per eNodeB)
6.4.3 Precautions
l During manual configuration of LOFD-080216 Uu based Soft Synchronization in
scenarios with LOFD-001037 RAN Sharing with Dedicated Carrier or LOFD-070206
Hybrid RAN Sharing deployed, one eNodeB has several IDs specified by the
ENBAISS.BaseStationId parameter. Only the ID of the primary operator is added when
the eNodeB is added to the synchronization zone.
l The longitudes and latitudes of eNodeBs must be configured first before the
eCoordinator automatically calculates eNodeB pairs after the ACT AISSNENBCALC
command is executed. If the attributes of an eNodeB pair are changed, run this command
again to activate an automatic eNodeB pairing calculation. The attribute changes include
changes of longitude and latitude of eNodeBs in the pair, addition and removal of
eNodeBs, X2 interfaces between eNodeBs, or cells under eNodeBs, and neighbor
relationship changes.
l In Uu-based soft synchronization, the signal strength is determined based on the
reference signal received power (RSRP) contained in event A3 reports. However, if the
TriggerQuantity parameter is set to RSRQ and the ReportQuantity parameter is set to
SAME_AS_TRIG_QUAN during the execution of the MOD CELLMCPARA
command, the eNodeB does not report RSRP. Therefore, do not set the TriggerQuantity
parameter to RSRQ or set the ReportQuantity parameter to SAME_AS_TRIG_QUAN
when Uu-based soft synchronization is required.
l Preamble blind detection cannot distinguish which preamble is used in Uu-based soft
synchronization. Therefore, the preambles on the same root sequence are not
recommended as the preamble for blind detection. Otherwise, exceptions will occur
during preamble blind detection. The following conditions must be met before enabling
Uu-based soft synchronization:
– The radius of all cells must be greater than 5 km to ensure normal preamble
allocation.
– The RachAdjSwitch(RachAdjSwitch) option of the
CellAlgoSwitch.RachAlgoSwitch parameter must be deselected.
l The time difference adjustment time must be later than the time difference measurement
time. If Uu-based soft synchronization is deployed for the first time and the time
difference adjustment time is earlier than the time difference measurement time, the time
difference cannot be adjusted until the second time difference adjustment time is reached
after the first time difference measurement. You are advised to enable Uu-based soft
synchronization at least one day earlier than the time specified by parameter settings.
6.4.4 Data Preparation and Feature Activation

eRAN
6.4.4.1 Data Preparation

The following tables list parameters that must be configured on the eNodeB side related to
Uu-based soft synchronization configuration, synchronous Ethernet configuration, longitude
and latitude configuration, and GPS and NTP configuration.
The following table lists parameters used to specify whether to enable Uu-based soft
synchronization.
Parameter Name Parameter ID Setting Notes Data Source
Air Interface Soft AISS.FLAG Set this parameter to Radio network plan
Synchronization ON(On). (internal planning)
Switch
Soft-synchronized AISS.NETMODE This parameter Radio network plan

Network Adaptive specifies the (internal planning)
Mode adaptive mode of the
soft synchronous
transport network. If
the network jitter is
large, set this
parameter to
ENH(Enhanced
Mode). Otherwise,
set this parameter to
GEN(General
Mode). This
parameter does not
apply to eGBTS.
Air Soft Syn Phase AISS.FREQUENC This parameter This parameter is

Adjustment Period E specifies the negotiated with the
adjustment period of peer end.
the frame clock
phase when the Uu
interface soft
synchronization
Phase Lock function
is enabled on the
eNodeB.

eRAN
Air Interface Soft AISS.STANDARD This parameter This parameter is

Synchronization specifies the RAT in negotiated with the
standard a multimode base peer end.
station to perform
Uu-based soft
synchronization.
l In a GL dual-
mode base
station:
If the base
station is
equipped with a
GTMU, the RAT
to perform Uu-
based soft
synchronization
must be set to
GSM.
If the base
station is not
equipped with a
GTMU, the RAT
to perform Uu-
based soft
synchronization
can be set to
GSM or LTE.
l In a GUL
multimode base
station:
If the base
station is
equipped with a
GTMU, the RAT
to perform Uu-
based soft
synchronization
must be set to
GSM.
If the base
station is not
equipped with a
GTMU, the RAT
to perform Uu-
based soft
synchronization
can be set to
GSM or LTE.

eRAN
l In an LTE-only
base station or a
UL dual-mode
base station, the
RAT to perform
Uu-based soft
synchronization
must be set to
LTE.
The following table lists parameters related to synchronous Ethernet configuration.
Link No. SYNCETH.LN Set this parameter to Network plan

0. (negotiation not
required)
Port No. SYNCETH.PN This parameter Network plan

specifies the number (negotiation not
of the port where the required)
synchronous-
Ethernet clock link
is configured. Set
this port and the
synchronous
Ethernet clock
source in the same
network.
SSM Selection SYNCETH.SSM Set this parameter to Network plan

the same value as (negotiation not
the setting on the required)
Ethernet clock
server.
Priority SYNCETH.PRI When two or more Network plan

clock sources are (negotiation not
used, a smaller value required)
of this parameter
specifies a higher
priority.
Set this parameter to
its default value
when the
synchronous
Ethernet is the only
clock source.

eRAN
Clock Working CLKMODE.MOD It is recommended Network plan

Mode E that this parameter (negotiation not
be set to required)
MANUAL(Manual
).
Selected Clock CLKMODE.CLKS Set this parameter to Network plan

Source RC SYNCETH(SyncEt (negotiation not
h Clock). required)
Clock Source No. CLKMODE.SRCN Set this parameter to Network plan

O the same value as (negotiation not
the established clock required)
link number.
Clock CLKSYNCMODE. The clock source Network plan

Synchronization CLKSYNCMODE supports only (negotiation not
Mode frequency required)
synchronization.
Therefore, set this
parameter to
FREQ(FREQ).
The following table lists parameters related to the configuration of longitudes and latitudes of
eNodeBs.
Location Name LOCATION.LOCA This parameter Network plan

TIONNAME specifies the (negotiation not
location name of the required)
eNodeB.
Geo-coordinate Data LOCATION.GCDF This parameter Network plan

Format specifies the format (negotiation not
of geographical required)
coordinates.
Latitude With LOCATION.LATI This parameter Network plan

Degree Format TUDEDEGFORM specifies the altitude (negotiation not
AT of the eNodeB. A required)
negative value
indicates the south
latitude and a
positive value
indicates the north
latitude.

eRAN
Longitude With LOCATION.LONG This parameter Network plan

Degree Format ITUDEDEGFORM specifies the (negotiation not
AT longitude of the base required)
station. A negative
value indicates the
west longitude and a
positive value
indicates the east
longitude.
(Optional) The following table lists parameters related to the configuration of GPS and the
NTP server.
GPS Clock No. GPS.GN This parameter Radio network plan

specifies the number (internal planning)
of the GPS clock
link.
GPS Work Mode GPS.MODE This parameter Radio network plan

specifies the (internal planning)
working mode of the
satellite card. Set
this parameter to
GPS(GPS). If the
eMBMS feature is
required, the
reference eNodeB
must have GPS
installed.
Time Source TIMESRC.TIMES This parameter Radio network plan

RC specifies the (internal planning)
external reference
time source of the
NE.
IPv4 Address of NTPC.IP This parameter Radio network plan

NTP Server specifies the IPv4 (internal planning)
address of the NTP
server.

eRAN
Port Number NTPC.PORT This parameter Radio network plan

specifies the port (internal planning)
number of the NTP
server. An NTP
client performs time
calibration with the
NTP server through
the port specified by
this parameter.
Authentication NTPC.AUTHMOD This parameter Radio network plan

Mode E specifies the (internal planning)
encryption mode. If
this parameter is set
to PLAIN, data is
transmitted in
plaintext.
The following tables list parameters that must be configured on the eCoordinator side related
to synchronization zone configuration, eNodeB addition, and eNodeB pair configuration.
The following table lists parameters related to synchronization zone configuration.
Synchronization AISSZONE.AISSZ This parameter Network plan

Zone ID oneId specifies the unique (negotiation not
ID of a Uu-based required)
soft synchronization
zone.
Time Adjust Period AISSZONE.Adjust This parameter Network plan

Period specifies the cycle in (negotiation not
which the eNodeB required)
time is adjusted.
Time Measure AISSZONE.Measu This parameter Network plan

Period rePeriod specifies the cycle in (negotiation not
which the eNodeB required)
time is measured.
The time is
measured per cycle.

eRAN
Adjust Threshold AISSZONE.Adjust This parameter Network plan

Threshold specifies the (negotiation not
threshold for required)
adjusting the
eNodeB time. The
eNodeB time is not
adjusted when the
time difference is
less than this
threshold.
Start Time for AISSZONE.Measu This parameter Network plan

Measurement reTime specifies the start (negotiation not
time for measuring required)
time difference
between eNodeBs in
a Uu-based soft
synchronization
zone.
Adjust Time AISSZONE.Adjust This parameter Network plan

Time specifies the (negotiation not
scheduled timing for required)
adjusting the time of
an eNodeB in the
Uu-based soft
synchronization
zone.
Frequency Band AISSZONE.Freque This parameter Network plan

ncyBand specifies the (negotiation not
frequency band on required)
which a cell in the
Uu-based soft
synchronization
zone works. For
details about this
parameter, see 3GPP
TS 36.104. For cells
in the Uu-based soft
synchronization
zone, the frequency
band and downlink
EARFCN
configuration must
meet the relationship
specified in 3GPP
TS 36.104.

eRAN
Downlink EARFCN AISSZONE.DLFre This parameter Network plan

quency specifies the (negotiation not
downlink EARFCN required)
for a cell in the Uu-
based soft
synchronization
zone. For details
about this parameter,
see 3GPP TS
36.104.
Downlink AISSZONE.DLBan The parameter Network plan

Bandwidth dWidth specifies the (negotiation not
downlink bandwidth required)
of a cell. The
downlink bandwidth
is denoted by
number of RBs. If
to CELL_BW_N25,
25 RBs are allocated
in the downlink. If
to CELL_BW_N50,
50 RBs are allocated
in the downlink. For
details about this
parameter, see 3GPP
TS 36.104.
RSRP Threshold AISSZONE.RSRPT This parameter Network plan

hreshold specifies the (negotiation not
minimum RSRP of a required)
cell that a UE
measures. A larger
value of this
parameter results in
better signal quality
of the area in the cell
in which the UE is
located and better
random access
performance.

eRAN
A3 Offset for Soft AISSZONE.A3Off This parameter Network plan

Synchronization specifies the offset (negotiation not
used to trigger event required)
A3. The event A3
itself is reported by
UEs which measure
the time difference
on the edge of
neighboring cells.
For details about this
parameter, see 3GPP
TS 36.331.
A larger value of
this parameter
results in fewer UEs
reporting event A3
and a lower
probability of CEUs
being selected for
time difference
measurements. A
smaller value of this
parameter results in
a longer distance
between the UE and
the neighboring cell,
and a lower
probability that
preambles sent by
the UE are being
blindly detected by
the neighboring cell.
CEU Punish Time AISSZONE.Punish This parameter Network plan

Time specifies the interval (negotiation not
at which a CEU required)
cannot perform a
time difference
measurement after
the previous
measurement ends.
A parameter either
too large or too
small in value has
negative impacts on
the time difference
measurements of
CEUs.

eRAN
Blind Detection AISSZONE.Detect This parameter Network plan

Duration LastTime specifies the (negotiation not
duration for required)
preamble blind
detection on a
neighboring
eNodeB. A larger
value of this
parameter requires
higher baseband
processing
capability. A smaller
value of this
parameter decreases
the success rate of
blind detection.
Leap Second AISSZONE.LEAPS This parameter Radio network plan

Adjustment Value ECOND specifies the leap (internal planning)
second value of the
Coordinated
Universal Time
(UTC). The NTP
time is derived from
UTC, which
deviates from the
GPS time in the
level of leap
seconds. Therefore,
the eNodeB must
consider the leap
second deviation
when converting the
NTP time to the
GPS time.
The following table lists parameters used to add eNodeBs into the synchronization zone.
Base Station MCC ENBAISS.BaseStati This parameter Network plan

onMCC specifies the MCC (negotiation not
of a base station in a required)
Uu-based soft
synchronization
zone.

eRAN
Base Station MNC ENBAISS.BaseStati This parameter Network plan

onMNC specifies the MNC (negotiation not
of a base station in a required)
Uu-based soft
synchronization
zone.
Base Station ID ENBAISS.BaseStati This parameter Network plan

onId specifies the ID of a (negotiation not
base station in a Uu- required)
based soft
synchronization
zone.
LPN Or Not ENBAISS.IsLPN This parameter Network plan

specifies whether an (negotiation not
eNodeB is a lower required)
power node (LPN).
The following table lists parameters related to the configuration of eNodeB pairs.
MCC of Base AISSNENB.BaseSt This parameter Network plan

Station 1 ation1MCC specifies the mobile (negotiation not
country code (MCC) required)
of base station 1.
MNC of Base AISSNENB.BaseSt This parameter Network plan

Station 1 ation1MNC specifies the mobile (negotiation not
network code required)
(MNC) of base
station 1.
MCC of Base AISSNENB.BaseSt This parameter Network plan

Station 2 ation2MCC specifies the MCC (negotiation not
of base station 2. required)
MNC of Base AISSNENB.BaseSt This parameter Network plan

Station 2 ation2MNC specifies the MNC (negotiation not
of base station 2. required)
6.4.4.2 Using the CME

For detailed operations, see CME-based Feature Configuration.

eRAN
6.4.4.3 Using MML Commands

Step 1 Enable Uu-based soft synchronization on eNodeBs.
Run the SET AISS command to set the FLAG parameter to ON(On) and set the
STANDARD parameter to LTE(LTE).
Step 2 Configure synchronous Ethernet on eNodeBs.
Run the ADD SYNCETH command to add synchronous Ethernet links.
Run the SET CLKMODE command to set the reference clock source to the synchronous
Ethernet clock.
Run the SET CLKSYNCMODE command to set the clock synchronization mode to
frequency synchronization.
Step 3 Configure eNodeBs' longitudes and latitudes on eNodeBs.
Run the ADD LOCATION command on eNodeBs to configure longitudes and latitudes of
eNodeBs.
Step 4 Configure a synchronization zone using the eCoordinator.
Run the ADD AISSZONE command to configure a synchronization zone.
Step 5 Add eNodeBs to the synchronization zone using the eCoordinator.
Run the ADD ENBAISS command to add eNodeBs to the synchronization zone.
Step 6 (Optional) Configure GPS on one eNodeB (This eNodeB does not require synchronous
Ethernet.)
Run the ADD GPS command to add GPS, or run the ADD IPCLKLINK command to add
the IP clock link.
Run the SET CLKMODE command to set the reference clock source to GPS.
Run the SET CLKSYNCMODE command on eNodeBs to set the clock synchronization
mode to time synchronization.
Step 7 (Optional) Configure NTP on all eNodeBs in the synchronization zone.
Run the SET TIMESRC command to set the reference clock source to NTP.
Run the ADD NTPC command to configure the IP address, port number, timing period, and
encryption mode of the NTP server. Run the SET MASTERNTPS command to configure
parameters related to the master NTP server.
Step 8 Add eNodeB pairs on the eCoordinator. eNodeB pairs can be added either automatically or
manually. eNodeB pairs are automatically added by default and can be manually adjusted.
l Adding eNodeB pairs automatically for Uu-based soft synchronization
Run the ACT AISSZONE command to activate the synchronization zone.
Run the ACT AISSNENBCALC command to activate automatic eNodeB pairing
calculation.
l Adding eNodeB pairs manually for Uu-based soft synchronization
Run the ADD AISSNENB command to add eNodeBs into eNodeB pairs for
synchronization.

eRAN
Run the ACT AISSZONE command to activate the synchronization zone.
----End
6.4.4.4 MML Command Examples

//1. Enabling Uu-based soft synchronization on eNodeBs
SET AISS:FLAG=ON, STANDARD=LTE, NETMODE=ENH, FREQUENCE=480SEC;
//2. Configuring synchronous Ethernet on eNodeBs

ADD ETHPORT:SN=7, SBT=BASE_BOARD, PA=COPPER, SPEED=AUTO, DUPLEX=AUTO;
ADD SYNCETH:LN=0, SN=7, PN=0;
SET CLKMODE:MODE=MANUAL, CLKSRC=SYNCETH;
SET CLKSYNCMODE:CLKSYNCMODE=FREQ;
//3. Configuring eNodeBs' longitudes and latitudes on eNodeBs

ADD LOCATION: LOCATIONNAME="hangzhou_NODE_ONE", GCDF=Degree, LATITUDEDEGFORMAT=0,
LONGITUDEDEGFORMAT=0;
//4. Configuring a synchronization zone on the eCoordinator

To configure a synchronization zone with the following parameter settings: The
synchronization zone ID is 0, the time difference adjustment interval is one day, the time
difference measurement interval is one day, the start time for time difference measurement is
10:00:00, the time difference measurement duration is 60 minutes, the time difference
adjustment time is 02:00:00, the number of required time difference measurement reports is
10, the threshold for adjusting eNodeB time is 5 µs, the immediate adjustment switch is off,
the frequency band is band 30, the downlink EARFCN is 9770, the downlink bandwidth is 3
MHz, the blind detection avoidance switch is on, the RSRP threshold is -45, the A3 offset for
soft synchronization is -8, the blind detection duration is 100s, and the blind detection
window size is 10. Run the following command:
ADD AISSZONE: AISSZoneId=0, AdjustPeriod=1, MeasurePeriod=1, AdjustThreshold=10,
MeasureTime=10&00&00, MeasureLast=60, AdjustTime=02&00&00, MeasureReportNUM=10,
AlarmThreshold=50, ImmediateAdjustSwitch=OFF, FrequencyBand=30, DLFrequency=
9770, DLBandWidth=CELL_BW_N15, DetectAvoidSwitch=ON, RSRPThreshold=-45, A3Off=-8,
PunishTime=100, DetectLastTime=100, DetectWindowSize=10;
//5. Adding eNodeBs to the synchronization zone on the eCoordinator

To add eNodeBs to the synchronization zone with the following parameter settings: The
synchronization zone ID is 0, the mobile country code (MCC) of the eNodeBs is 460, the
mobile network code (MNC) of the eNodeBs is 60, the IDs of the eNodeBs are 1 and 2,
eNodeB 1 is a non-reference eNodeB, and eNodeB 2 is a reference eNodeB, neither eNodeB
is a low power node. Run the following commands:
ADD ENBAISS:AISSZoneId=0, BaseStationMCC="460", BaseStationMNC="60",
BaseStationId=1, IsLPN=NO, BaseStationType= NORMALBASE;
ADD ENBAISS:AISSZoneId=0, BaseStationMCC="460", BaseStationMNC="60",
BaseStationId=2, IsLPN=0, BaseStationType= PRIBASE;
//Adding eNodeBs into eNodeB pairs on the eCoordinator

To add eNodeBs into eNodeB pairs with the following parameter settings: The
synchronization zone ID is 0, the MCC, MNC, and ID of eNodeB 1 are 460, 60, and 1,
respectively, and the MCC, MNC, and ID of eNodeB 2 are 460, 60, and 2, respectively. Run
the following command:
ADD AISSNENB: AISSZoneId=0, BaseStation1MCC="460", BaseStation1MNC="60",
BaseStation1Id =1, BaseStation2MCC="460", BaseStation2MNC="60", BaseStation2Id =2;
//6. (Optional) Configuring GPS on one eNodeB

eRAN
ADD GPS: GN=0, CN=0, SN=7, CABLETYPE=COAXIAL, CABLE_LEN=1000, MODE=GPS, PRI=4;

SET CLKMODE: MODE=MANUAL, CLKSRC=GPS;
SET CLKSYNCMODE: CLKSYNCMODE=TIME;
//7. (Optional) Configuring NTP on all eNodeBs in the synchronization zone

SET TIMESRC: TIMESRC=NTP;
To add NTP clients with the following parameter settings: IP mode is set to IPv4, IP address
of the NTP server is 192.168.88.168, port number of the NTP server is 123, timing period is
10, and encryption mode in plain text. Run the following command:
ADD NTPC: MODE=IPV4, IP="192.168.88.168", PORT=123, SYNCCYCLE=10, AUTHMODE=PLAIN;
To set the master NTP server with the IP protocol set to IPv4 and the IP address set to
192.168.88.168, run the following command:
SET MASTERNTPS:MODE=IPV4, IP="192.168.88.168";
//8.1 Adding eNodeB pairs automatically for Uu-based soft synchronization

ACT AISSZONE: AISSZoneId=0;
ACT AISSNENBCALC: AISSZoneId=0;
//8.2 Adding eNodeB pairs manually for Uu-based soft synchronization

ADD AISSNENB: AISSZoneId=0, BaseStation1MCC="460", BaseStation1MNC="60",
BaseStation1Id=0, BaseStation2MCC="460", BaseStation2MNC="60", BaseStation2Id=2;
ACT AISSZONE: AISSZoneId=0;
6.4.5 Activation Observation

Observe Whether Uu-based Soft Synchronization Takes Effect
Step 1 After timing adjustment on eNodeBs and new time differences are measured, run the DSP
AISSZONEINFO command on the eCoordinator to query values of parameters Clock
Synchronization State and Uu based Soft Synchronization State of eNodeBs within the
synchronization zone.
Step 2 Verify that the Clock Synchronization State parameter value is Phase Synchronization or
Frequency Synchronization, and the Uu based Soft Synchronization State parameter value
is Normal, indicating that Uu-based soft synchronization takes effect.
----End
Observe Whether NTP Takes Effect

l Query the NTP status on the U2000.
Step 1 Check the NTP operating status on the U2000 by running the following LINUX/UNIX
command:
$ /usr/sbin/ntpq -p
remote refid st t when poll reach delay offset jitter
============================================================
*192.168.8.12 .LCL. 1 u 29 64 177 0.240 0.093 1.222
l Information displayed in the remote column indicates the IP address of the NTP server.
l In the command output, 192.168.8.12 is the IP address of the NTP server. The symbol
"*" indicates the clock source is in the normal state. The symbol "*" is displayed five
minutes after the IP address is displayed.

eRAN
l Information in the st column indicates the level of the NTP server.

l The preceding command output indicates that 192.168.8.12 is in the first level.
If the displayed information is inconsistent with the preceding command output, the NTP
service is not in the normal state. When this occurs, contact Huawei technical support.
Step 2 Query the synchronization directory of the NTP server by running the following LINUX/
UNIX command:
$ /usr/sbin/ntptrace
localhost: stratum 6, offset 0.000000, synch distance 0.950193
192.168.8.12: stratum 1, offset 0.000000, synch distance 0.010010, refid 'LCL
l Information right behind localhost indicates the synchronization directory of the clock
source. The system traces all NTP synchronization links from the current NTP server to
its highest level.
l In the preceding command output, information "localhost: stratum 6" indicates the
current NTP server is at the sixth level, and information "192.168.8.12: stratum 1"
indicates the NTP server with the IP address 192.168.8.12 is at the first level.
Step 3 Query the system date and time of the NTP servers by running the following LINUX/UNIX
command:
$ date-R
If the system date and time of the NTP servers are incorrect, contact Huawei technical
support.
----End
l Query the NTP status on the eNodeB.
Step 1 Run the SET TIME command to change the eNodeB time to 00:00 in December 12, 2012.
Step 2 After the specified time synchronization period elapses, run the DSP TIME command and
check the Time parameter value. If the displayed Time parameter value is the same as the
NTP server time, the eNodeB time is correct.
Step 3 Run the DSP TIMESRC command to check the Clock Source parameter value. If the
displayed Clock Source parameter value is the same as the actual clock source, the NTP
configurations have taken effect.
----End
l Query the NTP state of all eNodeBs on the eCoordinator.
Step 1 Run the DSP AISSZONEINFO command to query whether the NTP Synchronization State
parameter value of all eNodeBs in the synchronization zone is Successful, and check the
eNodeB whose Clock Synchronization State parameter value is Phase Synchronization in
the command output shown in Step 2.
l If the NTP Time Precision State parameter value is Normal of an eNodeB, the NTP
server works properly.
l If the NTP Time Precision State parameter value is Abnormal of an eNodeB, the NTP
server may be not connected to the GPS.
----End

eRAN
Observe Whether Time Synchronization Between eNodeBs Has Completed

Step 1 On the eCoordinator, run the DSP AISSZONEINFO command to check that the Clock
Synchronization State parameter value is Phase Synchronization or Frequency
Synchronization, and the Uu based Soft Synchronization State parameter value is Normal
on all eNodeBs within a synchronization zone.
Step 2 If absolute time synchronization between eNodeBs is required, observe whether NTP takes
effect by performing operation described in Observe Whether NTP Takes Effect.
----End
6.4.6 Deactivation
Table 6-1 lists the parameter required for deactivating the Uu based Soft Synchronization
feature.
Table 6-1 Parameter required for deactivating the Uu based Soft Synchronization feature
MO Parameter Group Remarks
AISSZONE AISSZoneId N/A
The Uu based Soft Synchronization feature can be deactivated using the CME or MML
commands.
6.4.6.1 Using the CME

For detailed operations, see CME-based Feature Configuration.
6.4.6.2 Using MML Commands

Deactivating a synchronization zone on the eCoordinator
Run the DEA AISSZONE command to deactivate a synchronization zone.
6.4.6.3 MML Command Examples

Deactivating a synchronization zone on the eCoordinator
DEA AISSZONE: AISSZoneId=0;
6.4.7 Reconfiguration
None.
6.5 Performance Monitoring

eRAN
6.5.1 Time Difference Measurements Between eNodeBs in

eNodeB Pairs
Time difference measurement failures may be caused by unsuccessful preamble allocation,
unsuccessful preamble blind detection enabling, or unsuccessful preamble blind detection. In
most cases, time difference measurement failures are caused by unsuccessful preamble blind
detection.
l Time difference measurements based on UEs in inter-eNodeB handovers

The source eNodeB maintains performance counters L.AISS.IntereNodeB.HoMeas.Att
and L.AISS.IntereNodeB.HoMeas.Succ. If the source eNodeB instructs a UE in inter-
eNodeB handovers to measure the time difference between the two eNodeBs, the
L.AISS.IntereNodeB.HoMeas.Att counter value increases by 1. If the source eNodeB
successfully calculates the time difference, the L.AISS.IntereNodeB.HoMeas.Succ
counter value increases by 1.
l Time difference measurements based on CEUs
The serving eNodeB maintains performance counters
L.AISS.IntereNodeB.CeMeas.Att and L.AISS.IntereNodeB.CeMeas.Succ. If the
serving eNodeB instructs a CEU to measure the time difference between the two
eNodeBs, the L.AISS.IntereNodeB.CeMeas.Att counter value increases by 1. If the
serving eNodeB successfully calculates the time difference, the
L.AISS.IntereNodeB.CeMeas.Succ counter value increases by 1.
6.5.2 Absolute Values of Average Time Difference Changes

Between eNodeBs
If a time adjustment is not performed based on the measured time differences, the absolute
values of the time differences between eNodeBs in eNodeB pairs indicate the synchronization
maintenance performance of synchronous Ethernet. The synchronization maintenance
performance is monitored based on the counters listed in the following table.
The following table lists counters measuring the distributions of absolute values of average
time difference changes between eNodeBs.
Counter Name NE
VS.eCoordinator.AISS.AbsAvgTdifVarCnt0 eCoordinator
_15
5_30
0_45
5_60
0_75
5_92

eRAN
Counter Name NE
2
NOTE
The preceding counters measure the number of time difference changes fallen into different ranges of
absolute values of average time difference changes between eNodeBs in eNodeB pairs.
6.5.3 Absolute Values of Average Time Differences Between

eNodeBs
During synchronization tracing, the absolute values of average time differences between
eNodeBs indicate the time synchronization performance of Uu-based soft synchronization.
The time synchronization performance is monitored based on counters listed in the following
table.
The following table lists counters measuring the distributions of absolute values of average
time differences between eNodeBs.
Counter Name NE
VS.eCoordinator.AISS.AbsAvgTdifCnt0_15 eCoordinator
0
0_45
0
5
2
VS.eCoordinator.AISS.AbsAvgTdifCnt92 eCoordinator
NOTE
The preceding counters measure the number of time differences fallen into different ranges of absolute
values of average time differences between eNodeBs in eNodeB pairs.
The absolute value of average time difference is in the unit of TS, which equals (1/30.72) µs.
6.6 Parameter Optimization

Parameters related to Uu-based soft synchronization can be optimized to improve
synchronization performance.

eRAN
If the success rate of time difference measurement between eNodeBs in eNodeB pairs is low,
you are advised to set parameters AISSZONE.RSRPThreshold and AISSZONE.A3OFF to
larger values in order to increase the success rate. For details about the counters measuring the
time difference measurement success rate, see 6.5.1 Time Difference Measurements
Between eNodeBs in eNodeB Pairs. Descriptions of parameters are as follows:
l AISSZONE.RSRPThreshold: This parameter specifies the minimum RSRP of a cell
that a UE measures. A larger value of this parameter results in better signal quality of the
area in the cell in which the UE is located and better random access performance.
l AISSZONE.A3OFF: This parameter specifies the offset for triggering event A3 by UEs
measuring the time difference on the edge of neighboring cells. For details about this
parameter, see 3GPP TS 36.331. A larger value of this parameter results in fewer UEs
reporting event A3 and a lower probability of CEUs being selected for time difference
measurements. A smaller value of this parameter results in a longer distance between the
UE and the neighboring cell, and a lower probability that preambles sent by the UE are
being blindly detected by the neighboring cell.
If the eNodeB reports ALM-22702 Feature Function Disabled Abnormal with the cause value
"The peer data is missing", the time difference reports of more than 50% eNodeB pairs are not
collected. In this case, you are advised to decrease the AISSZONE.PunishTime parameter
value or increase the AISSZONE.MeasureLast parameter value to increase the probability of
the time difference report collection. Descriptions of parameters are as follows:
l AISSZONE.PunishTime: This parameter specifies the interval at which a CEU cannot
perform a time difference measurement after the previous measurement ends. A
parameter either too large or too small in value has negative impacts on the time
difference measurements of CEUs.
l AISSZONE.MeasureLast: This parameter specifies the duration of a time difference
measurement in Uu-based soft synchronization.
6.7 Possible Issues
6.7.1 Related Alarms

Alarms listed in Table 6-2 have been introduced to accommodate this feature.
Table 6-2 Alarms related to Uu-based soft synchronization

Alarm ID Alarm Name NE Description
ALM-22702 Feature Function eNodeB Related features

Disabled Abnormal cannot work
properly.

eRAN
Alarm ID Alarm Name NE Description
ALM-22709 Synchronization eCoordinator The eCoordinator

State of eNodeB cannot adjust the
Abnormal time on eNodeBs,
and the eNodeBs
have the possibility
of entering the out-
of-synchronization
state, and features
depending on time
synchronization
between eNodeBs
are affected.
NOTE
For alarms related to GPS and synchronous Ethernet, see Synchronization Feature Parameter
Description.
6.7.2 Handling Exceptions on Message Reporting

If the AISS_INFO_RSP and AISS_MEAS_START_RSP messages fail to be reported, locate
the reasons for reporting failures as follows:
Any of the following reasons will contribute to AISS_INFO_RSP reporting failures:
l Parameters LOCATION.Latitude and LOCATION.Longtitude are not configured.
l The local eNodeB does not have cells supporting time difference measurements for Uu-
based soft synchronization.
l The local eNodeB has cells supporting time difference measurements for Uu-based soft
synchronization. However, UEs in these cells cannot be handed over to cells under
neighboring eNodeBs through X2-based handovers.
Any of the following reasons will contribute to AISS_MEAS_START_RSP reporting failures:
l The local eNodeB does not have cells supporting time difference measurements for Uu-
based soft synchronization, and all neighboring eNodeBs report handover failures.
l The local eNodeB has cells supporting time difference measurements for Uu-based soft
synchronization. However, UEs in these cells cannot be handed over to cells under one
neighboring eNodeB through X2-based handovers, the eNodeB reports handover
failures.
To determine whether a local eNodeB has cells supporting time difference measurements for
Uu-based soft synchronization, perform the following operations:
1. Filter out cells whose Cell.FreqBand parameter value or Cell.DLBandWidth parameter
value does not meet setting requirements for the Uu-based soft synchronization zone.
2. Filter out cells not in the active state.
3. Filter out cells established on LBBPc boards.
4. Filter out 4R cells that are established on LBBPd boards and whose
PrachConfigTimeStagSwitch is set to OFF(Off) or PrachConfigIndexCfgInd is set to

eRAN
CFG(Configure). The BBPs serving cells can be queried by running the DSP CELL
command.
5. Filter out cells whose MultiRruCellFlag is set to BOOLEAN_TRUE(True).
6. Filter out cells whose HighSpeedFlag is not set to LOW_SPEED(Low speed cell flag).
7. Filter out cells whose cell radius is less than 5 km and that are selected in PRACH
allocation.
8. Filter out cells with RACH resource allocation enabled (The
RachAdjSwitch(RachAdjSwitch) option of the RachAlgoSwitch parameter is
selected).
NOTE
Use the U2000 as a proxy to log in to the eCoordinator to trace messages over the Se interface between
the eCoordinator and eNodeBs.

eRAN
Description 7 Parameters
7 Parameters
Table 7-1 Parameters

MO Parame MML Feature Feature Description
ter ID Comma ID Name
nd
Cell FreqBan ADD LBFD-0 Cell Meaning: Indicates the frequency band in which a cell
d CELL 0201803 Selectio operates. For details about this parameter, see 3GPP
ADD / n and TS 36.104. For details about the usage of 252 to 255,
CELLB TDLBF Re- see the following LTE-U forum document: eNodeB
AND D-00201 selection Minimum Requirements for LTE-U SDL V1.0. This
803 Broadca parameter applies only to LTE FDD and LTE TDD.
LST
CELLB LBFD-0 st of GUI Value Range: 1~256
AND 02009 / system Unit: None
TDLBF informat
MOD D-00200 ion Actual Value Range: 1~256
CELL 9 Default Value: None
Multi-
RMV LBFD-0 Band
CELLB 70103 / Compati
AND TDLBF bility
LST D-00201 Enhance
CELL 806 ment
LEOFD- License
111301 d
Assisted
Access
(LAA)
for CA

eRAN

nd
Cell DlEarfc ADD LBFD-0 Broadca Meaning: Indicates the DL EARFCN of the cell. For
n CELL 02009 / st of details about this parameter, see 3GPP TS 36.104. For
MOD TDLBF system the detailed usage of 255144 to 262143, see the
CELL D-00200 informat following LTE-U forum document: eNodeB Minimum
9 ion Requirements for LTE-U SDL V1.0. This parameter
LST applies only to LTE FDD and LTE TDD.
CELL LBFD-0 Coverag
0201801 e Based GUI Value Range:
/ Intra- 0~68485,255144~256143,260894~262143
TDLBF frequenc Unit: None
D-00201 y
801 Actual Value Range:
Handov 0~68485,255144~256143,260894~262143
LBFD-0 er
0201803 Default Value: None
License
/ d
TDLBF Assisted
D-00201 Access
803 (LAA)
LEOFD- for CA
111301
Cell DlBand ADD LOFD-0 Compac Meaning: Indicates the DL bandwidth of the cell,
Width CELL 01051 t which is based on the number of resource blocks
MOD LBFD-0 Bandwi (RBs). The value CELL_BW_N25 indicates a cell
CELL 02009 / dth bandwidth of 25 RBs. The value CELL_BW_N50
TDLBF Broadca indicates a cell bandwidth of 50 RBs. The mapping
DSP between the parameter value and the actual cell
DDCEL D-00200 st of
9 system bandwidth (that is, the number of RBs) can be
LGROU deduced similarly. For details, see 3GPP TS 36.104.
P TDLBF informat
ion This parameter applies only to LTE FDD and LTE
LST D-00100 TDD.
CELL 3 Scalable
Bandwi GUI Value Range: CELL_BW_N6(1.4M),
dth CELL_BW_N15(3M), CELL_BW_N25(5M),
CELL_BW_N50(10M), CELL_BW_N75(15M),
CELL_BW_N100(20M)
Unit: None
Actual Value Range: CELL_BW_N6,
CELL_BW_N15, CELL_BW_N25, CELL_BW_N50,
CELL_BW_N75, CELL_BW_N100
Default Value: None

eRAN

nd
TASM FLAG SET GBFD-1 Soft- Meaning: Indicates whether the Air interface Soft
AISS 18201 Synchro synchronization Phase Lock function is enabled on the
LST LOFD-0 nized NE, which can be set to ON or OFF. ON indicates that
AISS 80216 Network the switch for the Air interface soft synchronization
Uu phase lock function is set to on and OFF indicates that
based the Air interface soft synchronization phase lock
Soft function is set to off. Only GSM and LTE FDD
Synchro currently support this function.
nization GUI Value Range: ON(On), OFF(Off)
Unit: None
Actual Value Range: ON, OFF
Default Value: OFF(Off)
TASM STAND SET None None Meaning: Indicates the standard where the Air
ARD AISS interface soft synchronization function is enabled.
LST GUI Value Range: GSM(GSM), LTE(LTE)
AISS Unit: None
Actual Value Range: GSM, LTE
Default Value: GSM(GSM)
TASM NETMO SET GBFD-1 Soft- Meaning: Indicates the adaptive mode of the soft
DE AISS 18201 Synchro synchronous transport network. The value of this
LST LOFD-0 nized parameter depends on the synchronous status of the
AISS 80216 Network transport network.
Uu GUI Value Range: GEN(General Mode),
based ENH(Enhanced Mode)
Soft Unit: None
Synchro
nization Actual Value Range: GEN, ENH
Default Value: GEN(General Mode)
TASM FREQU SET GBFD-1 Soft- Meaning: Indicates the adjustment period of the frame
ENCE AISS 18201 Synchro clock phase when the Air interface soft
LST LOFD-0 nized synchronization Phase Lock function is enabled on the
AISS 80216 Network NE.
Uu GUI Value Range: 300SEC(300 Seconds),
based 480SEC(480 Seconds)
Soft Unit: None
Synchro
nization Actual Value Range: 300SEC, 480SEC
Default Value: 300SEC(300 Seconds)

eRAN

nd
SYNCE LN ADD WRFD- Clock Meaning: Indicates the number of the synchronous-
TH SYNCE 050502 Sync on Ethernet clock link. A maximum of two links can be
TH Ethernet configured currently.
DSP GUI Value Range: 0~1
SYNCE Unit: None
TH
Actual Value Range: 0~1
MOD
SYNCE Default Value: 0
TH
RMV
SYNCE
TH
LST
SYNCE
TH
SYNCE PN ADD WRFD- Clock Meaning: Indicates the number of the port where the
TH SYNCE 050502 Sync on synchronous-Ethernet clock link is configured.
TH Ethernet GUI Value Range: 0~5
LST Unit: None
SYNCE
TH Actual Value Range: 0~5
Default Value: 0
SYNCE SSM ADD WRFD- Clock Meaning:

TH SYNCE 050502 Sync on Indicates whether handling of SSM frames is
TH Ethernet supported. The setting of this parameter is consistent
MOD with the setting on the Ethernet clock server.
SYNCE
TH The synchronization status message(SSM)carries
clock quality information, which is specified in ITU-
DSP T.
SYNCE
TH This parameter is valid only when the synchronous-
LST Ethernet clock link is of the input type.
SYNCE GUI Value Range: DISABLE(DISABLE),
TH ENABLE(ENABLE)
Unit: None
Actual Value Range: DISABLE, ENABLE
Default Value: DISABLE(DISABLE)

eRAN

nd
SYNCE PRI ADD WRFD- Clock Meaning: Indicates the priority of the clock source.
TH SYNCE 050502 Sync on The value 1 indicates that the current clock source has
TH Ethernet the highest priority, and the value 4 indicates that the
MOD current clock source has the lowest priority.
SYNCE GUI Value Range: 1~4
TH
Unit: None
LST
SYNCE
TH Default Value: 4
TASM MODE SET MRFD- BTS Meaning: Indicates the working mode of the system
CLKM 210501 Clock clock. Manual indicates that a clock source must be
ODE specified by the user. Auto indicates that the system
DSP automatically selects a clock source based on the
CLKST priority and availability of the clock source. Free
AT indicates that the system clock works in free-running
mode, that is, the system clock does not trace any
LST reference clock source.
CLKM
ODE GUI Value Range: AUTO(Auto), MANUAL(Manual),
FREE(Free)
Unit: None
Actual Value Range: AUTO, MANUAL, FREE
Default Value: FREE(Free)
TASM CLKSR SET MRFD- BTS Meaning: Indicates the type of the user-selected clock
C CLKM 210501 Clock source.
ODE GUI Value Range: GPS(GPS Clock), BITS(BITS
LST Clock), IPCLK(IP Clock), SYNCETH(SyncEth
CLKM Clock), LINECLK(Line Clock), TOD(TOD Clock),
ODE PEERCLK(Peer Clock), SYNCETH+IPCLK(SyncEth
Clock+IP Clock), GPS+SYNCETH(GPS Clock
+SyncEth Clock), INTERCLK(Inter Clock)
Unit: None
Actual Value Range: GPS, BITS, IPCLK, SYNCETH,
LINECLK, TOD, PEERCLK, SYNCETH+IPCLK,
GPS+SYNCETH, INTERCLK
Default Value: GPS(GPS Clock)

eRAN

nd
TASM SRCNO SET MRFD- BTS Meaning: Indicates the clock link number of the
CLKM 210501 Clock reference clock source. When the Selected Clock
ODE Source parameter is set to GPS+SYNCETH, this
DSP parameter indicates the number of the GPS clock link.
CLKSR When the Selected Clock Source parameter is set to
C SYNCETH+IPCLK, this parameter indicates the
number of the IP clock link. When this parameter is
DSP set to AUTO, the system selects an available clock
PHASE link from those of the specified reference clock
DIFF source. If there is more than one clock link and the
LST selected clock link fails, another available clock link
CLKM will be used.
ODE GUI Value Range: 0(0), 1(1), 2(2), 3(3), 4(4), 5(5),
6(6), 7(7), 8(8), 9(9), 10(10), 11(11), 12(12), 13(13),
14(14), 15(15), 16(16), 17(17), AUTO(AUTO)
Unit: None
Actual Value Range: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, AUTO
Default Value: 0(0)
TASM CLKSY SET MRFD- BTS Meaning: Indicates the clock synchronization mode of
NCMO CLKSY 210501 Clock a BS, which can be frequency synchronization or time
DE NCMO synchronization.
DE GUI Value Range: FREQ(FREQ), TIME(TIME),
DSP HYBRID(HYBRID)
CLKST Unit: None
AT
Actual Value Range: FREQ, TIME, HYBRID
LST
CLKSY Default Value: FREQ(FREQ)
NCMO
DE
LOCATI LOCATI ADD None None Meaning: Indicates the location name of the base
ON ONNA LOCATI station.
ME ON GUI Value Range: 1~64 characters
LST Unit: None
LOCATI
ON Actual Value Range: 1~64 characters
MOD Default Value: None

LOCATI
ON
RMV
LOCATI
ON

eRAN

nd
LOCATI GCDF ADD None None Meaning: Indicates the format of geographical
ON LOCATI coordinates.
ON GUI Value Range: Degree(Degree), Second(Second)
MOD Unit: None
LOCATI
ON Actual Value Range: Degree, Second
LST Default Value: Degree(Degree)

LOCATI
ON
LOCATI LATITU ADD None None Meaning: Indicates the latitude of the base station. A
ON DEDEG LOCATI negative value indicates the south and a positive value
FORMA ON indicates the north.
T MOD GUI Value Range: -90000000~90000000
LOCATI Unit: 1e-6 degree
ON
Actual Value Range: -90~90
LST
LOCATI Default Value: 0
ON
LOCATI LONGI ADD None None Meaning: Indicates the longitude of the base station. A
ON TUDED LOCATI negative value indicates the west and a positive value
EGFOR ON indicates the east.
MAT MOD GUI Value Range: -180000000~180000000
LOCATI Unit: 1e-6 degree
ON
Actual Value Range: -180~180
LST
LOCATI Default Value: 0
ON
GPS GN ADD MRFD- BTS Meaning: Indicates the number of the GPS clock link.
GPS 210501 Clock GUI Value Range: 0~17
DSP Unit: None
GPS
MOD
GPS Default Value: 0
RMV
GPS
RST
SATCA
RD
LST
GPS

eRAN

nd
GPS MODE ADD MRFD- BTS Meaning: Indicates the working mode of the satellite
GPS 210501 Clock card. Satellite cards are classified into dual-mode
MOD satellite cards and single-mode satellite cards. A dual-
GPS mode satellite card supports two satellite searching
modes. For example, the working mode of a
DSP BDS/GPS satellite card can be BDS prioritized or
GPS GPS prioritized. In BDS prioritized mode, the satellite
LST card processes signals from BDS satellites only. In
GPS GPS prioritized mode, the satellite card processes
signals from GPS satellites only. A single-mode
satellite card supports only one satellite searching
mode. For example, a satellite card working in GPS
mode.
GUI Value Range: GPS(GPS),
GLONASS(GLONASS), GPS/GLONASS(GPS/
GLONASS with GPS Prioritized), BDS(BDS), BDS/
GPS(BDS/GPS with BDS Prioritized), GPS/
BDS(GPS/BDS with GPS Prioritized)
Unit: None
Actual Value Range: GPS, GLONASS, GPS/
GLONASS, BDS, BDS/GPS, GPS/BDS
Default Value: GPS(GPS)
TIMES TIMES SET None None Meaning: Indicates the external reference time source
RC RC TIMES of the NE.
RC GUI Value Range: NTP(NTP), GPS(GPS),
DSP NONE(None), SYSCLK(SYSCLK)
TIMES Unit: None
RC
Actual Value Range: NTP, GPS, NONE, SYSCLK
LST
LATES Default Value: NTP(NTP)
TSUCC
DATE
LST
TIMES
RC
NTPCP IP ADD None None Meaning: Indicates the IPv4 address of the NTP
NTPC server.
MOD GUI Value Range: Valid IP address
NTPC Unit: None
RMV Actual Value Range: Valid IP address
NTPC
Default Value: 0.0.0.0
SET
MASTE
RNTPS

eRAN

nd
NTPCP PORT ADD None None Meaning: Indicates the port number of the NTP server.
NTPC An NTP client performs time calibration with the NTP
MOD server through the port specified by this parameter.
NTPC GUI Value Range: 123~5999,6100~65534
LST Unit: None
NTPC Actual Value Range: 123~5999,6100~65534
Default Value: 123
NTPCP AUTH ADD None None Meaning: Indicates the encryption mode. If this
MODE NTPC parameter is set to PLAIN, data is transmitted in
MOD plaintext.
NTPC GUI Value Range: PLAIN(Plain), DES_S(DES_S),
LST DES_N(DES_N), DES_A(DES_A), MD5(MD5)
NTPC Unit: None
Actual Value Range: PLAIN, DES_S, DES_N,
DES_A, MD5
Default Value: PLAIN(Plain)

eRAN
Description 8 Counters
8 Counters
Table 8-1 Counters

Counter ID Counter Name Counter Feature ID Feature Name
Description
1526732913 L.AISS.IntereNode Number of times Multi-mode: None Uu based Soft

B.HoMeas.Att that an eNodeB GSM: None Synchronization
attempts to measure
the time difference UMTS: None
among eNodeBs by LTE:
using UEs LOFD-080216
performing inter-
eNodeB handovers

B.CeMeas.Att that an eNodeB GSM: None Synchronization
attempts to measure
the time difference UMTS: None
among eNodeBs by LTE:
using inter-eNodeB LOFD-080216
CEUs

B.HoMeas.Succ that an eNodeB GSM: None Synchronization
successfully
measures the time UMTS: None
difference among LTE:
eNodeBs by using LOFD-080216
UEs that are
performing inter-
eNodeB handovers

eRAN
Description 8 Counters
Counter ID Counter Name Counter Feature ID Feature Name

Description

B.CeMeas.Succ that an eNodeB GSM: None Synchronization
successfully
measures the time UMTS: None
difference among LTE:
eNodeBs by using LOFD-080216
inter-eNodeB CEUs

eRAN
Description 9 Glossary
9 Glossary
For the acronyms, abbreviations, terms, and definitions, see Glossary.

eRAN
Description 10 Reference Documents
10 Reference Documents
1. 3GPP TS 25.101, "User Equipment (UE) radio transmission and reception (FDD)"
2. 3GPP TS 25.211, "Physical channels and mapping of transport channels onto physical
channels (FDD)"
3. 3GPP TS 25.306, " UE Radio Access capabilities "
4. 3GPP TS 25.308, "UTRA High Speed Downlink Packet Access (HSPDA); Overall
description"
5. 3GPP TS 25.321, "Medium Access Control (MAC) protocol specification"
6. Common Transmission Feature Parameter Description in SingleRAN documentation
7. IP Transmission Feature Parameter Description
8. IP eRAN Engineering Guide Feature Parameter Description


Uu Based Soft Synchronization (ERAN12.1 - 03)

Uploaded by

Copyright:

Available Formats

Uu Based Soft Synchronization (ERAN12.1 - 03)

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Uu Based Soft Synchronization (ERAN12.1 - 03)

Uploaded by

Copyright:

Available Formats

eRAN

Uu based Soft Synchronization

HUAWEI TECHNOLOGIES CO., LTD.

Trademarks and Permissions

Huawei Technologies Co., Ltd.

Issue 03 (2018-01-22) Huawei Proprietary and Confidential i

1 About This Document.................................................................................................................. 1

Issue 03 (2018-01-22) Huawei Proprietary and Confidential ii

Issue 03 (2018-01-22) Huawei Proprietary and Confidential iii

1 About This Document

1.2 Intended Audience

l Need to understand the features described herein

1.3 Change History

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 1

Change Change Description Parameter Affected

Feature None None N/A

Editorial Moved LOFD-001031 Extended None N/A

Change Change Description Parameter Affected

Feature None None N/A

Editorial Revised descriptions in Mutually None N/A

eRAN12.1 Draft A (2016-12-30)

Change Change Description Parameter Affected

Feature None None N/A

Editorial Revised descriptions in this None N/A

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 2

1.4 Differences Between eNodeB Types

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 3

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 4

Currently, eNodeBs support features related to time synchronization such as LBFD-00300503

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 5

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 6

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 7

Figure 3-1 Procedure for Uu-based soft synchronization

3.2 Initial Synchronization

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 8

Figure 3-2 Time difference measurement performed by UEs involved in inter-eNodeB

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 9

Figure 3-3 Time differences measured by CEUs performing random accesses

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 10

3.2.1 Determining the Synchronization Zone and eNodeB Pairs

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 11

Figure 3-4 Uu-based soft synchronization zone

Collecting information about eNodeB pairs

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 12

Figure 3-5 Collecting information about eNodeB pairs

3.2.2 Collecting Time Differences Between Paired eNodeBs

1. Starting time difference measurements

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 13

Figure 3-6 Starting time difference measurements

2. Updating parameters related to time difference measurements

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 14

Figure 3-7 Updating parameters related to time difference measurements

3. Sending time difference measurement reports

Figure 3-8 Sending time difference measurement reports

4. Stopping time difference measurements

Issue 03 (2018-01-22) Huawei Proprietary and Confidential 15

Figure 3-9 Stopping time difference measurements

3.2.3 Adjusting the Time on Non-reference eNodeBs Based on the

Figure 3-10 Adjusting time differences