Product Type Technical ProposalVI2011
TD-LTE Engineering Optimization Workflow
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Revision History
Product VersionDocument VersionSerial NumberRemarks
The first release
Author
Document VersionWritten onWritten byReviewed byApproved by
R1.02011-02-09Kang KaiYuan Haijun
Applicable to: LTE network optimization engineersSuggestion:
Before reading this document, you had better have the following
knowledge and skills:SNKnowledge and skillsReference material
1LTE theoriesTD-LTE Theories and Key Technologies V2.0
2
3
Follow-up document: After reading this document, you may need
the following information:SNReference materialRemarks
1TD-LTE Network Coverage Optimization Guide V1.7It describes how
to optimize the LTE network coverage effect.
2TD-LTE Signaling Flow V1.1It describes the whole workflow which
the signaling goes through.
3TD-LTE ZXPOS CNT Guide V1.0It introduces how to use the ZXPOS
CNT, a kind of drive test tool.
About This DocumentAbstractThis document is written to guide the
network optimization after the completion of eNodeB construction.
It focuses on the network optimization workflow, including the
prerequisites, the preparations, the plan and the implementation of
the network optimization. ChapterDescription
1 OverviewIt gives you an overview of this workflow.
2 PrerequisitesIt describes two prerequisites for the
engineering optimization.
3 ImplementationIt describes the whole optimization workflow in
details.
TABLE OF CONTENTS61Overview
62Prerequisites
72.1Network Planning
72.2eNodeB Commissioning
83Implementation
83.1Work Plan
93.2Workflow
93.2.1Preparations
103.2.2Parameter Review
103.2.3Cluster Optimization
103.2.4Coverage Optimization
103.2.5Service Optimization
113.2.6Area Optimization
113.2.7Border Optimization
113.2.8Whole Network Optimization
113.2.9Acceptance Test
123.3Tasks
123.3.1Data Acquisition
123.3.2Problem Analysis and Formulation of Optimization
Scheme
133.3.3Implementation of Optimization Scheme
143.3.4Optimization Verification
143.3.5Writing and Reviewing Optimization Report
1 OverviewThe network optimization functions to improve the
network performance by means of optimizing the coverage indicator,
the switchover indicator and the access indicator.
The network performance optimization can be evaluated by the
following aspects:
Coverage: The coverage related indicators include the RSRP,
CINR, RSRQ, coverage rate, receiving power, transmit power and
coverage mileage ratio. The RSRP/CINR/RSRQ indicates the network
coverage quality. The coverage mileage ratio indicates the coverage
status of the whole network. The coverage problems, including
coverage absence, weak coverage, coverage overshooting and pilot
pollution, may cause call drops and access failure. Therefore, the
coverage problem is the focus of the network optimization.
Quality: The quality related indicators include the throughput
efficiency, delay and block error rate (BLER).
Access: It is indicated by the access success rate. The access
is considered to be unsuccessful if the UE fails to set up the
service connection within the given time after it sends out the
access request message. In most cases, the unsuccessful access is
caused by the poor coverage, coverage overshooting, improper
neighboring cell settings, and interference.
Call-hold: It is indicated by the call-drop rate. In most cases,
the call drop is caused by the poor coverage, main cell absence,
improper neighboring cell settings, and interference.
Handover: It is indicated by the handover success rate.
Generally speaking, a detailed network optimization solution
should be worked out for the purpose of increasing the value of the
above indicators to desired level.
2 Prerequisites
The network optimization is performed upon the completion of
network planning and commissioning. Additionally, the network
optimization is launched only when a certain scale of eNodeBs are
commissioned. In this regard, tools designed for the network
planning, commissioning and optimization are to be used in the
stage of network optimization for the sake of time efficiency.
2.1 Network Planning
In the stage of network planning, the engineer leverages a
well-organized workflow to obtain the network construction scale
and the network construction parameters, which may guide the actual
network construction. The outcome of network planning exerts great
influence over the workload of future network optimization and the
network performance.
Therefore, the engineer needs to make a good plan for the
networking. He should provide the follow materials:
the eNodeB Information table;
the neighboring cells relationship table (providing the
information about the eNodeB altitude, eNodeB longitude, the
antenna azimuth, the antenna down tilt, the equipment height, PCI,
frequency, and RS power); and the simulation report.
2.2 eNodeB Commissioning
The network optimization launches only when:
the eNodeB is working properly and no alarm is reported;
all equipment is working properly and all reported alarms are
cleared;
all necessary tests are performed to prove that the service is
in normal status; the commissioning test records are provided for
the network optimization engineer.
the radio network planning parameters and the antenna &
feeder parameters are configured based on the network planning
result;
all radio planning parameters (including PCI, frequency and
power) are configured based on the network planning result;
the antenna is installed at the height, azimuth and down tilt
specified in the network planning result;
the actual height, azimuth and down tilt of the installed
antenna are provided for the network optimization engineer;
a certain scale of eNodeBs are commissioned;
eNodeBs are constructed in groups so as to save more time for
the network optimization;
the eNodeB construction plan is provided for the network
optimization engineer so that he can work out the optimization plan
with more information;
the eNodeB information table is provided for the network
optimization engineer;
all necessary information about the eNodeB (including the eNodeB
ID, the cell ID, the cell description, the eNodeB altitude, the
eNodeB longitude, the antenna height, the antenna down tilt, and
the antenna type) is provided after the completion of eNodeB
construction.
3 Implementation
3.1 Work Plan
Before the network optimization work is launched, a detailed
network optimization scheme concerning aspects such as the network
scale, network coverage area, eNodeB construction plan and network
acceptance data need to be worked out. Additionally, information
such as tools, human resources, vehicles and targets of the network
optimization are also included.
The outcome of network optimization includes:
1Completion time of network optimization in every cluster and
district and all necessary reports
2Arrangement of manpower, test tools and vehicles;
The manpower, test tools and vehicles are prepared based on the
resource configuration model, the completion time of network
optimization and the eNodeB construction plan.
3Layout of eNodeBs
Divide all eNodeBs into groups based on the eNodeB construction
plan. Thirty eNodeBs make up a cluster and several clusters make up
a district. The eNodeBs in the same cluster should be constructed
nearly at the same period so as to save more time for the network
optimization.
4) Content of daily/weekly network optimization report and the
recipients of the report
3.2 Workflow
3.2.1 PreparationsPrepare the following materials before the
launch of network optimization:
eNodeB information table: It provides the information about the
eNodeB name, eNodeB ID, MCC, TAC, eNodeB altitude, eNodeB
longitude, antenna height, antenna azimuth, antenna down tilt,
transmit power, frequency, PCI, ICIC and PRACH.
eNodeB commissioning information table and alarm information
table
map: It is the mapinfo map for the area where the network
covers
drive test software: Its license is also needed.
test UE: It is compatible with the drive test software.
test vehicle: prepare the test vehicles based on the network
optimization plan
power supply: vehicle power supply or UPS
working staff who take charge of antenna & feeder
adjustment
network optimization engineers
3.2.2 Parameter ReviewBefore the network optimization, the
engineer should review the key parameters of the eNodeBs in the
district to be optimized in order to confirm that the cell
configuration parameters are consistent with the planning results.
Otherwise, modify inconsistent parameters accordingly.
The key parameters include: frequency, neighbor cell, PCI,
power, handover/re-selection parameters, and PRACH parameters.
3.2.3 Cluster Optimization
The cluster optimization is performed based on the eNodeB
commissioning status. As for the dense urban, the cluster
optimization starts when more than 80% eNodeBs have been
commissioned in this area. As for suburban and rural areas, the
cluster optimization launches as long as the eNodeB begins to work
properly.
Make sure that the eNodeBs have been commissioned before the
cluster optimization. Besides, check that there are no alarms
reported and the eNodeBs to be optimized are working properly.
3.2.4 Coverage Optimization
The coverage optimization, which focuses on the RSRP, RSRQ and
CINR, is the most important part and the first step in the
engineering optimization. It involves the adjustment of the
engineering parameters, the power and the neighbor cell
relationship. After the adjustment of engineering parameters and RS
power, the engineering parameter list needs to be updated
immediately.3.2.5 Service Optimization
The service optimization should be done according to the plan
after the coverage optimization meets the requirement. Firstly,
test the long-time service holding capability. Later, check that
the handover success rate and the data service rate meet the
requirement. Next, test the short call of the basic services. Check
the access success rate and the call drop rate. If the service
cannot meet the requirement, the engineer needs to analyze causes
and then perform the optimization accordingly. The engineering
parameter list and the parameter modification tracking list should
be updated in time afterwards.3.2.6 Area Optimization
The coverage and service optimization of the whole area should
be done after the completion of cluster optimization. The area
optimization focuses on the cluster border and blind spots. Similar
to the workflow of cluster optimization, the coverage optimization
is performed ahead of the service optimization in the stage of area
optimization. It is suggested that the border optimization is done
by the group composed of optimization engineers in neighboring
clusters. In the process of area optimization, the engineering
parameter list and the parameter modification tracking list should
be updated in time. Moreover, the comparison report for the
original parameters and modified parameters is also needed.3.2.7
Border Optimization
The optimization of area border begins after the completion of
inner area optimization. The border coverage and service
optimization are done by a group composed of optimization engineers
from neighboring districts. When eNodeBs at both sides of the
border are provided by different manufacturers, the coverage
optimization and service optimization need to be done by group
composed of engineers from these two manufacturers. The coverage
and service optimization flows are exactly the same as the cluster
optimization flow. In the process of border optimization, the
engineering parameter list and the parameter modification tracking
list should be updated in time. Moreover, the comparison report for
the original parameters and modified parameters is also
needed.3.2.8 Whole Network OptimizationDuring the whole network
optimization, the optimization engineer needs to perform the DT
test for the whole network so as to get a clear idea of the network
coverage and the service status. He then needs to optimize the
coverage and service of roads and areas required by the customer.
The coverage and service optimization flows are exactly the same as
the cluster optimization flow. In the process of whole network
optimization, the engineering parameter list and the parameter
modification tracking list should be updated in time. Moreover, the
comparison report for the original parameters and modified
parameters is also needed.3.2.9 Acceptance TestThe acceptance test
for the network performance is done based on the acceptance
standard. The test routes, test points and call modes are chosen
according to the contract or the principles determined in the
requirement analysis stage. In most cases, the customer should
attend the acceptance test.The acceptance test is carried out for
the purpose of finding out the optimization effect. In this regard,
great importance should be attached to it because its result exerts
great impact on the project. During the acceptance test, the
optimization engineers should do as follows:
(1) participate into the discussion and confirmation of test
items;(2) work out the acceptance criteria according to test items
and expected optimization effect;(3) skip step 1 and 2 if the test
items and acceptance criteria are determined by the customer;(4)
work out the DT routes and conduct the pre-test before the formal
test.3.3 Tasks3.3.1 Data Acquisition3.3.1.1 Task
DescriptionPurpose: Collect the network performance data and give
it to the optimization engineers for analysis.
Principal: test engineers
Input: digital map, eNodeB datasheet, test plan
Output: DT\CQT\background data
Contents: Work out the test plan and collect required data based
on the specific network optimization project. Give the test data to
the optimization engineers so that they can analyze and locate
problems.3.3.2 Problem Analysis and Formulation of Optimization
Scheme3.3.2.1 Task Description
Purpose: Work out an optimization scheme by means of network
performance evaluation, problem analysis and problem locating.
Conduct the scheme.Principal: optimization engineers
Input: test data
Output: scheme of Optimization and adjustment Contents: Analyze
data, locate problem and then work out the network optimization
scheme. All members in the project or the designated personnel
review the scheme in order to avoid or modify improper
operations.3.3.3 Implementation of Optimization Scheme3.3.3.1 Task
Description
Purpose: Conduct the network optimization according to the
scheme.Principal: equipment engineers
Input: scheme of optimization and adjustment Output:
optimization and adjustment recordContents: Conduct all items in
the network optimization scheme; record the results and necessary
processes based on the actual situation.3.3.3.2 PrecautionsPay
attention to the following items when implementing the optimization
scheme:
(1) Email the adjustment table to the equipment engineers
involved in the optimization scheme according to the optimization
adjustment scheme. The email should also be sent to the project
manager, the email sender and relevant personnel. Make sure that
all adjustment items are clearly described in the table attached to
the email, e.g. adding neighbor cell to the cell 1011 or the ID of
the new neighbor cell is 1042.
(2) Record all information accurately when the DT engineer calls
the engineer in the equipment room to modify parameters at the
backend.
(3) Send a formal adjustment table to the third party involved
in the optimization scheme (e.g. adjusting the antenna) in
triplicate. The copies of adjustment table should be sent to the
engineering team, the project manager and the sender.
(4) Make an appointment with the engineering team in
advance.
(5) Verify the optimization effect after the scheme is
implemented.
(6) Restore all modified parameters to their original status if
necessary.3.3.4 Optimization Verification3.3.4.1 Task
Description
Purpose: Verify the optimization effect by means of various
tests after the completion of the scheme.
Principal: Test engineers
Input: optimization and adjustment record; original network
performance dataOutput: Comparison of the network performance
before and after the adjustmentContents: after the implementation
of the optimization scheme, collect data as required. Compare and
analyze the data collected before and after the adjustment. Collect
data in the same network environment if possible so to work out
accurate verification result.
Make sure that the network problem is solved and the network
performance meets the requirement. Otherwise, go back to the step
of data acquisition and repeat the whole process.3.3.4.2
Precautions(1) Use the same test tool before and after the
optimization if possible.
(2) Choose the same test route before and after the
optimization.
(3) Check whether the loading test is being performed in the
test area or not.
(4) Conduct the test at the same time of the day in order to
ensure the data is obtained in the same radio network
environment.
(5) The UE should move at the same speed.3.3.5 Writing and
Reviewing Optimization Report
Purpose: Work out the network optimization report. Record the
measures used in the network optimization and the optimization
effect in the report.
Principal: optimization engineers
Input: all data of the optimization process
Output: network optimization report (including the optimization
& adjustment scheme, and the comparison of engineering
parameters before and after the optimization)
Contents: Work out the network optimization report. Record the
measures used in the network optimization and the optimization
effect in the report. Assist members in the project or the
designated personnel in reviewing the Network Optimization Report.
Modify the report based on their comments.VI2011
ZTE Confidential Proprietary 2011 ZTE Corporation. All rights
reserved.5
_1360682364.vsd
Network optimization
Review optimization parameters
Optimize clusters
Optimize borders
Optimize edges
Optimize whole network
Optimize covergae
Optimize service
Acceptance Test
Go to next workflow
Work out optimization report for every stage
Prepare for network optimization
