FDD-LTE Single Site Verification Course Objectives: 1. Know and master the SSV workflow 2. Know and master SSV back-end preparations 3. Know and master SSV front-end tests 4. Know and master SSV acceptance criteria 5. Know and master SSV typical cases
Contents 1
Overview ........................................................................................................................... 1
2
SSV Workflow ................................................................................................................... 2
3
Back-End Preparations ................................................................................................... 3 3.1
Basic Data Acquisition ............................................................................................. 3
3.2
System Health Checks ............................................................................................. 4 3.2.1 Hardware ........................................................................................................ 4 3.2.2 Back-End Parameters .................................................................................... 6 3.2.3 Transmission Configuration Checks .............................................................. 6 3.2.4 RSSI KPI Checks ........................................................................................... 7
4
Front-End Verification ..................................................................................................... 8 4.1
Antenna Feeder Parameter Verification .................................................................. 9
4.2
Function and Service Tests ................................................................................... 10 4.2.1 Precautions .................................................................................................. 10 4.2.2 CQT Tests .................................................................................................... 11 4.2.3 Drive Tests ................................................................................................... 14
5
SSV Acceptance Criteria ............................................................................................... 15 5.1
6
Indoor Distribution SSV KPI Criteria ...................................................................... 16
Typical Problems in Single Site Optimization ............................................................ 17 6.1
Site Signals ............................................................................................................ 17 6.1.1 Signals Are Not Stable Because R8862A RRUs Are Not Compatible With the System.......................................................................................................... 17 6.1.2 Uplink and Downlink Frequency Bands Are Not Supported by RRUs ........ 18
6.2
A UE Cannot Attach to the Network or Initiate a Call ............................................ 19 6.2.1 The UE Authentication Fails Because the UE Account Is Delinquent ......... 19 6.2.2 The UE Cannot Attach to the Network Because the TAC Is Not Configured Properly ........................................................................................................ 20
6.3
Service Exception .................................................................................................. 22 6.3.1 Uplink and Downlink Rates Are Improper Because the Optical Fiber of the RRU is Loose ........................................................................................................ 22 6.3.2 The Rate Is Abnormal Because IPRAN Transport Data Is Wrongly Configured 23
Figures Figure 2-1 SSV Workflow ................................................................................................................ 2 Figure 3-1 Alarm Monitor Window .................................................................................................. 5 Figure 3-2 Checking the Transport Bandwidth ............................................................................... 6 Figure 3-3 Transport Link Diagnosis Test....................................................................................... 7 Figure 3-4 Checking RSSI .............................................................................................................. 7 Figure 4-1 Antenna Installation Position ......................................................................................... 9 Figure 4-2 Installation Environment ................................................................................................ 9 Figure 4-3 Controlling the UE Connection State .......................................................................... 11 Figure 4-4 Cell Configurations in Unipos CNT ............................................................................. 11 Figure 4-5 Rate Test Screenshot .................................................................................................. 13 Figure 4-6 Average RTT Delay ..................................................................................................... 14
Tables Figure 3-1 SSV Hardware Check Record ....................................................................................... 5 Table 4-1 SSV Test Tools ............................................................................................................... 8 Table 4-2 Test Points and Coverage Ranges .............................................................................. 10 Table 5-1 Outdoor SSV KPI Criteria (Recommended) ................................................................. 15 Table 5-2 Indoor Distribution SSV KPI Criteria (Recommended) ................................................ 16
1
Overview Single Site Verification (SSV) is fundamental to network optimization. A site SSV can be performed after the site is constructed and commissioned. SSV checks whether cells of a site can provide basic functions and be covered by signals properly, checks whether engineering installations and parameter settings are the same as planned, verifies site locations and radio environment in the areas to be optimized, and obtains authentic basic data for cluster optimization and network optimization. The following tasks need to be finished during SSV: Verify engineering survey data, including the longitude and latitude of a site. Verify that the antenna feeder system complies with the design based on the aspects of azimuth, downtilt, height, and antenna model, and use drive tests to verify that no antenna feeder is inversely connected. Verify that site parameters (TAC and PCI parameters) are configured as the network optimization plan. Verify that an eNodeB can enter the network based on the KPIs of the eNodeB, such as hardware alarms, output power, transmission delay and bandwidth, and noise floor. Check pilot RSRP and SINR in drive tests to verify that the coverage of an eNodeB is proper. Verify that service KPIs of a site meet criteria, including attach or access performance, uplink or downlink rate, ping delay, and voice services. It is recommended that the SSV flow in this guide can be complied with during actual operations. Results and reports shall be submitted after each eNodeB is verified. If a customer has additional requirements, a special negotiation can be organized.
2
SSV Workflow Figure 2-1
SSV Workflow
Start
Acquire basic data and formulate the eNodeB inforamtion table
Back-end preparations
Check system health and formulate the system health report
Verify antenna feeder parameters and formulate a verification report
Upload antenna feeder parameters? Initial access
Front-end verifications
Yes
Update the eNodeB information table
No
UL/DL rate Ping delay Sector coverage
Verify services and functions
Analyze and solve faults
Handover in the eNodeB VoIP
Meet KPI requirements? Yes
Formulate reports
No
Note: Basic data acquisition and system health checks can be performed simultaneously. Front-end verifications can start only after back-end preparations are finished without any faults. The work scope of antenna feeder verification must be confirmed by the customer in the project initiation phase. It is recommended that the customer organizes an installation team or tower workers to verify antenna feeders. Any problem in basic data acquisition, system health checks, and antenna feeder parameter verifications needs to be fixed immediately. If a problem cannot be solved, it can be left unsolved temporarily with the approval of the customer. All problems should be recorded in the problem tracking table. The KPIs are references for function and service tests only.
3
Back-End Preparations Back-end preparations include: 1.
Obtaining basic information about a site, including the location, environment, address, contact, and keys.
— Ensure that the test team can locate the site and enter the work site quickly. 2.
System health checks, including the checks on site hardware, transport, standing wave ratio alarms, cell lock-out status, and configuration parameters.
— Ensure that the eNodeB operates properly before any tests.
3.1
3.
Planning drive test routes in advance to save the time to be used in drive tests.
4.
Test tools and maps.
Basic Data Acquisition Obtain basic data of the sites from the customer and engineering commissioning team, including site location, environment, address, contact, and keys. Build up and update the eNodeB database.
3.2
System Health Checks System health checks can be performed on the following aspects.
3.2.1
Hardware Hardware installations and alarms can be checked. 1.
Hardware: The hardware engineering team can set up a daily-updated specific record and transfer the record to the network optimization team, therefore the network optimization team can determine whether hardware is completely installed at an eNodeB.
Verify that the BBUs, RRUs, transport network, antenna feeders, and cables between units are properly installed, and that the board indicators operate properly. If the engineering team has the test tools, for example, a portable Tphone or PC, the engineering team can implement basic tests on the eNodeB after the eNodeB is constructed. The key work is to verify that the uplink and downlink rates are proper, and that the antenna feeders are connected properly. 2.
Alarm: Check whether there is any alarm in the Alarm Monitor window of the OMMB. If there are alarms, the SSV needs to be arranged after the engineering team clears the alarms.
Figure 3-1
Alarm Monitor Window
The hardware check record and eNodeB health check record must be filled in after the system health checks are finished.
Figure 3-1 Unit BBU
SSV Hardware Check Record Result OK
Problem None 1.
RRU
The power indicator on the RRU of cell 3 is off.
1. No electronic tunable Antenna
antenna is connected in cell 1.
link
OK
Other
None 1.
Alarms
Cell 1 standing wave ratio
OK
Remarks
None
Power cables need
to
replaced.
be
3.2.2
Back-End Parameters Check whether back-end parameters are configured in accordance with the network plan. The following parameters need to be paid attention to:
3.2.3
(1)
TAC
(2)
PCI
(3)
Upstream and downlink frequency points, and bandwidth
(4)
Prach parameters
(5)
Encryption algorithms and security algorithms
(6)
Downlink transmit power/reference signal power settings
(7)
UE transport mode
(8)
Neighboring cells
Transmission Configuration Checks You need to verify that the transmission bandwidth and link quality are proper. Transport bandwidth: Select OMMB > Configuration Management > Bandwidth Assignment, and verify that the bandwidth is sufficient. The Maximum Bandwidth of Egress (Mbps) parameter is set to 1000.
Figure 3-2
Checking the Transport Bandwidth
Transport link quality: select Diagnosis Test > IP Channel Test.
Figure 3-3
Transport Link Diagnosis Test
The link quality diagnosis tests the KPIs of the S1 link such as the packet loss rate, delay, and jitter. In most cases, the delay of the S1 link is 2 ms.
3.2.4
RSSI KPI Checks You can use the diagnosis test function or back-end KPI data to check whether RSSI is proper.
Figure 3-4
Checking RSSI
If RSSI is not proper, the SSV can be performed only after the faults are fixed.
4
Front-End Verifications Front-end verification needs the following tools:
Table 4-1
SSV Test Tools
No.
Test Tools
Quantity
Front-end data collection 1
software
Back-end 2
1
Description CXT or other software that supports LTE network tests
data
processing and analysis
1
CXA or other software
software 3
UE or other terminal for tests
1 The handheld GPS device collects precise
Handheld GPS device 4
and GPS antenna with a
longitude and latitude of the site or antenna. 1+1
suction cup
The antenna with a suction cup provides GPS information during data collection. The antenna must have a USB interface.
5
Vehicle-mounted inverter
1
Supplies power to the testers.
6
Compass
1
Tests antenna azimuth.
7
Goniometer
1
Tests the antenna downtilt.
8
USB hub (optional)
1
Provides more USB interfaces.
9
Camera
1
10
SIM card
1
11
Laptop
1
12
Electronic map
1
13
Vehicle
1
Takes photos on the devices, antennas, buildings, and environment. Used for testing services. Used for testing services. A quad-core CPU and 4 GB memory is recommended. Provides geographic information for drive tests. Has enough space or a platform for tests, and installed with a lighter or batteries. FTP server residing in the subnet. The
14
FTP server
1
hardware, software, and egress bandwidth meets test requirements.
4.1
Antenna Feeder Parameter Verifications Data of an antenna feeder must be collected on the top of a building. Photos of the antenna and the environment must be taken. It is recommended that the photos of the environment should be taken every 45°, meaning that eight photos of the environment are required.
Figure 4-1
Antenna Installation Position
Figure 4-2
Installation Environment
Verify that the longitude, latitude, height, azimuth, downtilt, model of the antenna are configured as planned, there is no obstacle around the antenna, and the antenna is far enough away from other systems.
4.2
Function and Service Tests
4.2.1
Precautions The precautions for testing the functions and services are briefly described as follows: The following information describes how to define the coverage requirements of test points and how to control the connection between a UE to the network.
There is near-end, middle, and far-end test points based on the RSRP range and SINR range.
Table 4-2
Test Points and Coverage Ranges
Test Point
RSRP Range (dBm)
Near-end test point
SINR Range (dB)
>=-85
>=23
Middle test point
-85>RSRP>=-95
23>SINR>=15
Far-end test point
-95>RRSP>=-105
15>SINR>=0
A UE using a Qualcomm chip (such as MF821 and MF823) is attached to the network automatically after the UE is started. You can tap Connect on the dial screen of the UE to connect to the network and carry out the tests, but you cannot detach the UE from the network or reattach the UE to the network. You can control the connection between the UE and the network in the Test Controller
window
of
the
CNT
test
software
(Attach/Detach/Network
Connect/Network Disconnect), see the Figure 4-3. To attach the UE to the network or detach the UE from the network, you can drag an operation from the left pane to the middle pane (see 1), select the operation in the middle pane, select the UE in the right pane (see 2), and then click RIGHT ARROW (see 3).
Figure 4-3
Controlling the UE Connection State
Before the tests, verify that the tested signals belong to the corresponding sector and the parameters are configured properly.
Figure 4-4
Cell Configurations in Unipos CNT
After verifying that all parameters are configured properly, start the tests. There are CQT test and DT tests.
4.2.2
CQT Tests CQT tests verify that the performance indexes of all sectors meet network access requirements.
CQT tests need to be carried out at the near-end point for all sectors. The near-end test point needs to be confirmed by the customer. CQT tests include the access performance test, upstream and downstream speed test, and PING delay test. Note: 1. The SINR of the near-end point must be greater than 23 dB. It is difficult to select a near-end point because the environmental is complicated. Use the dynamic management function of the OMM to block signals of neighboring cells to select the near-end point with the approval of the customer. 2. If the customer does not allow to block signals of neighboring cells, negotiate with the customer to test the middle test point instead of the near-end point. To carry tests at the middle test point, the acceptance criteria need to be lowered.
4.2.2.1
Testing Initial Access (Attach) 1. Connect the test UE and test software. 2. Make the UE camp on the near-end test point of the cell to be tested. 3. Initiate the Attach flow through the software manually or automatically to attach the UE to the cell. 4. Open the MS-DOS screen on the UE-side PC. 5. Run the ping
-l 32 –n 30> command to ping the authorized server. 6. After the ping operation ends, detach the UE. 7. Repeat steps 3 to 6 twice. 8. Record and save test data.
4.2.2.2
Testing Uplink and Downlink Rate 1. Connect the test UE and test software. 2. Make the UE camp on the near-end test point of the cell to be tested. 3. Make the UE access the network.
4. Use the FTP software (for example, FileZilla) to test uplink and downlink FTP services separately for three minutes. It is recommended to test ten threads and multiple software at the same time. 5. Use the DU meter or Net meter to record the peak rates and average rates of uplink and downlink FTP services and save related screenshots. 6. (Optional) Make the UE camp on the middle test point of the cell. 7. Repeat steps 3 to 5. 8. (Optional) Make the UE camp on the far-end test point. 9. Repeat steps 3 to 5. 10. Record and save test data.
Figure 4-5
4.2.2.3
Rate Test Screenshot
Testing the User Plane Delay 1. Connect the test UE and test software. 2. Make the UE camp on the near-end test point of the cell to be tested. 3. Make the UE access the network. 4. Open the MS-DOS screen on the UE-side PC.
5. Run the ping -l 32 –n 60> command to ping the authorized server. 6. Collect the average RTT delay (see Figure 4-6). 7. Record test data and save related screenshots.
Figure 4-6
4.2.3
Average RTT Delay
Drive Tests The drive tests in SSV only check the sector coverage performance and antenna feeder connections without requirements on KPIs.
4.2.3.1
Testing Sector Coverage and Handover 1. Connect the test UE and test software. 2. Use the UE to initiate a call to access the network. 3. Start the downlink FTP test. 4. Move the vehicle along main roads around the site to be tested. 5. Verify that the coverage is proper, and determine whether any antenna feeder is connected in inversion based on PCI distribution. 6. Verify that the UE can hand over from one sector to another properly.
7. Record and save test data.
4.2.3.2
(Optional) Testing the VoIP Service 1. If the UE does not support the VoIP service, this test can be omitted. 2. Connect the test UE and test software. 3. Start the UE to make the UE camp on the near-end test point of the cell to be tested. 4. Make the UE access the network. 5. Use the UE to initiate a three to five-minute call to another subscriber. 6. Repeat Step 3 for five times. 7. Use the UE to answer a three to five-minute call from another subscriber. 8. Repeat Step 5 for five times. 9. Record and save test data.
5
SSV Acceptance Criteria Whether the SSV can be accepted depends on KPIs.
Outdoor SSV KPI Criteria
Table 5-1 No.
1
Outdoor SSV KPI Criteria (Recommended) KPI
Ping delay
Criterion
<=30ms
Attach 2
success rate
100%
Remarks
For the middle test point: UL peak
3
rate
>= 15Mbps@15MHz
>= 30Mbps@15MHz
DL peak
4
>= 20Mbps@20MHz
>= 40Mbps@20MHz
rate
For the middle test point: >=85Mbps@20MHz
>= 50Mbps@20MHz
>= 80Mbps@15MHz
>= 40Mbps@15MHz
DT KPIs The direction and coverage of all sectors are basically the 1
Coverage
same as planned, and no antenna feeder is connected in inversion. Clockwise and counterclockwise handover at the eNodeB
2
are proper. Data services are not interrupted. The FTP
Handover
service rate does not drop off. (Optional)
3
5.1
VoIP
service
The UE can initiate or answer a quality call properly.
Indoor Distribution SSV KPI Criteria All test points of an indoor distribution SSV need to meet the following KPI criteria.
Table 5-2
Indoor Distribution SSV KPI Criteria (Recommended)
No.
1 2
KPI
Ping delay Attach success rate
Criterion
<=30ms 100% Dual-channel outdoor distribution Single-channel
3
UL peak rate
distribution >= 20Mbps@20MHz >= 15Mbps@15MHz
outdoor
Dual-channel outdoor distribution >=85Mbps@20MHz >= 80Mbps@15MHz 4
DL peak rate
Single-channel
outdoor
distribution >=40Mbps@20MHz >= 35Mbps@15MHz
The indoor distribution SSV does not require any drive test.
6
Typical
Problems
in
Single
Site
Optimization 6.1
Site Signals
6.1.1
Signals Are Not Stable Because R8862A RRUs Are Not Compatible With the System 1.
Symptom The signals of some sites are not stable, and services cannot be accessed through the sites.
2.
Analysis The RRUs used on the sites are 8862A in V3.10.20P02B08. The software running on the boards is not compatible with the R8862A RRUs.
3.
Solution Upload the software running on the boards in the entire network.
6.1.2
Uplink and Downlink Frequency Bands Are Not Supported by RRUs 1.
Symptom The signals of sector 3 of a site are unstable and usually drop off. The RSRP value changes greatly.
2.
Analysis The frequency bands of the site are not configured in the supportive range of the RRU. The supportive frequency bands of common RRUs are listed as follows:
R8882 S1800 B6B UL: 1710-1785
R8862A S1800 A6A
DL: 1805-1880
UL: 1735-1780
DL: 1830-1875
R8862A S1800 A4A UL: 1735-1780
DL: 1830-1875
The RRU is 9963A S1800A4A. The carrier frequency exceeds the supportive range of the RRU.
3.
Solution Modify the carrier frequency properly. Signals can be transmitted properly.
6.2
A UE Cannot Attach to the Network or Initiate a Call
6.2.1
The UE Authentication Fails Because the UE Account Is Delinquent 1.
Symptom A UE cannot initiate calls. The back end shows that the MME responds the UE authentication request with a reject message.
2.
Analysis There is no fault in the back-end parameters. The test team still cannot initiate any call after moving to another site. After tracing the problem with the CN side, the CN side indicates that the authentication fails because the SIM account is in delinquent.
3.
Solution Recharge or replace the test SIM card.
6.2.2
The UE Cannot Attach to the Network Because the TAC Is Not Configured Properly 1.
Symptom The UE cannot attach to the network during the tests on a sector. The following figure shows the signaling trace results.
2.
Analysis After checking the back-end parameters, the test engineers find that the TCA is set to 9472. The TAC is not configured as planned.
3.
Solution Use the planned TAC 9520. The problem is solved.
6.3
Service Exception
6.3.1
Uplink and Downlink Rates Are Improper Because the Optical Fiber of the RRU is Loose 1.
Symptom The downlink rate of sector 3 is low and fluctuates greatly in a site test. The other two sectors are proper.
2.
Analysis There is no faulty parameter found in the back-end check. The test UE and FTP server are proper. The product engineer finds that optical fiber is not plugged properly when checking cable connections during the test of pinging the server.
3.
Solution Reconnect the optical fiber. The problem is solved. The peak download rate reaches 104 Mbps, and the average download rate reaches 95 Mbps.
6.3.2
The Rate Is Abnormal Because IPRAN Transport Data Is Wrongly Configured 1.
Symptom The uplink rate and downlink rate of a site are improperly. The downlink rate is lower than 1 Mbps, and the uplink rate is only several Kbps. The back-end service check shows that the MME always releases the UE because of “transport resource unavailable”.
2.
Analysis The UE can initiate a call, meaning that the signaling plane is proper. The keys of problem analysis are eNodeB version, transport configurations, and service configurations. The engineers find that the transport links are low quality. The packet loss rate reaches 100%, and the delay is greater than 100 ms.
3.
Solution The transport engineers find that data configuration is improper. The service rate at the site resumes after data is reconfigured.
