Sabtu, 05 Oktober 2013

LTE KPI test procedure : Latency

1.1    Latency

1.1.1      Round Trip Time

Name:  Maximum round trip latency
Purpose: To verify that Round Trip Time  remains within acceptable range
Measurement method
 Time stamp of “PING Response received by the UE" - Time stamp of “PING Request sent by the UE
Acceptable range
Average time less than 40 ms

 

1.1.1.1      Test conditions and requirements

This test is to measure round trip time (RTT) in given test network in stationary conditions
Specifically the procedure starts at transmission of PING Request by the UE and ends at the reception of PING Response at the UE.
Radio latency is round trip time between PDCP layer of UE and PDCP layer of eNB. Single user per cell scenario is to be considered.
Radio latency will be measured using ordinary ping.
As shown in the figure below, end-to-end latency is the sum of radio latency and core latency.
But there can be some uncertainties in core latency because the backhaul delay and delay induced in PDN are variable.
Core latency shall be separately measured and radio latency is calculated by end-to-end latency minus core latency.




Ÿ A vehicle for moving, a test UE, and a test laptop computer connected with GPS and the UE are required.
Ÿ 2ms backhaul delay between eNB and EPC is assumed.
Ÿ Assumes UE processing time = 1ms. (one way)
Ÿ The network stability is certainly guaranteed.

1.1.1.2       Test description

1.     Locate the test UE at a predefined place with good link condition.
2.     The test point should be over the cell edge RF conditions. (RSRP: higher than -100dBm, SNR: higher than 5)
3.      Connect the UE to eNB. (Initial attachment)
4.      Generate 32-bytes ping packet 100 times using DOS windows.
5.      Calculate the min, average and max value of Round trip time.
6.      Average Round trip time is calculated using measured data between 5th percentile and 95th percentile.

1.1.1.3      Pass/Fail Criteria

Ÿ The average round trip time shall be less than 40ms. (median of 95% tile)


Appendix A – Acronyms


DM                   Diagnostic Monitor
eNB                  E-UTRAN NodeB
EPC                 Evolved Packet Core
FTP                  File Transfer Protocol
GBR                  Guaranteed Bit Rate
KPI                   Key Performance Indicators
LTE                  Long Term Evolution
MIMO               Multiple Input Multiple Output
MME                Mobility Management Entity
OCNS               Other Cell Noise Simulator
PCRF               Policy and Charging Rules Function
PDN                 Packet Data Network
P-GW               PDN Gateway
QCI                    QoS Class Identifier
RRC                 Radio Resource Control
RSRP               Reference Signal Received Power
S-GW               Serving Gateway
SIMO                Single Input Multiple Output
SINR                 Signal to Interference and Noise power Ratio
TCP                  Transmission Control Protocol
UE                    User Equipment
UDP                 User Datagram Protocol


LTE KPI test procedure : DL User Throughput

1.1.1      DL User Throughput (Ave.)

NameDL User Throughput (Ave.)
Purpose:  To verify that a UE is supported average download throughput
Measurement method
During driving the Cell coverage, Measure Download Traffic rate using FTP
Acceptable range
More than 15Mbps.

1.1.1.1      Test conditions and requirements


Ÿ A laptop computer to monitor the UE and DM tool for UE.
Ÿ Test route shall be predetermined in the test network.
Ÿ Network shall be designed to support minimum data rates of 1 Mbps DL and 256 kbps UL.
Ÿ There is no throughput limit on the FTP server.
Ÿ System configuration is set to #2 UL - DL Configuration and #7 Special_subframe_configuration.
Ÿ UE and PC are supported maximum throughput. (no limit)

1.1.1.2      Test procedure

1.     Locate the UE at a predefined place.
2.     The test point should be over the cell edge RF conditions. (RSRP: higher than -100dBm)
3.     Connect the UE to eNB. (Initial attachment)
4.     Run FTP client at the laptop and Connect to the FTP server.
5.     Start to download traffic.
6.     Drive the vehicle to the predefined route within the cell.
7.     Measure the average data rate during the test by DM or other tool.
8.     Report the results.

1.1.1.3      Pass/Fail criteria

Ÿ The DL average UE throughput shall be higher than acceptable range.


1.1.2      UL User Throughput (Ave.)

Name: UL User Throughput (Ave.)
Purpose: To verify that a UE is supported average upload throughput
Measurement method
During driving the Cell coverage, Measure upload Traffic rate using FTP
Acceptable range
More than 3Mbps.

1.1.2.1      Test conditions and requirements


Ÿ A laptop computer to monitor the UE and DM tool for UE.
Ÿ Test route shall be predetermined in the test network.
Ÿ Network shall be designed to support minimum data rates of 1 Mbps DL and 256 kbps UL.
Ÿ There is no throughput limit on the FTP server.
Ÿ System configuration is set to #2 UL - DL Configuration and #7 Special_subframe_configuration.
Ÿ UE and PC are supported maximum throughput. (no limit)

1.1.2.2      Test procedure

1.     Locate the UE at a predefined place.
2.     The test point should be over the cell edge RF conditions. (RSRP: higher than -100dBm)
3.     Connect the UE to eNB. (Initial attachment)
4.     Run FTP client at the laptop and Connect to the FTP server.
5.     Start to upload traffic.
6.     Drive the vehicle to the predefined route within the cell.
7.     Measure the average data rate during the test by DM or other tool.
8.     Report the results.

1.1.2.3      Pass/Fail Criteria


Ÿ The UL average UE throughput shall be higher than acceptable range.

LTE KPI test procedure(STC) v01 LABTest


1      Test ITEMS

1.1    Throughput

1.1.1      DL Cell Throughput (Max.)

NameDL Cell Throughput (Max.)
Purpose:  To verify that a cell is supported maximum download throughput   
Measurement method
FTP is used, peak sector DL data rate shall be more than 0.95 x acceptable range
Acceptable range
More than 90Mbps.

1.1.1.1      Test conditions and requirements


Ÿ Two laptop computers to monitor the two UEs and two DM tools.
Ÿ A location for test condition (Cell Near link condition) shall be predetermined in the single Cell environment.
Ÿ There is no throughput limit on the FTP server and backhaul.
Ÿ System configuration is set to #2 UL - DL Configuration and #7 Special_subframe_configuration.
Ÿ UEs and PCs are supported maximum throughput. (no limit)
Ÿ If FTP is used, peak sector DL data rate shall be higher than 0.95 x acceptable ranges.

1.1.1.2      Test procedure

1.      Locate the test UEs at a predefined place with near link condition in the single Cell environment.
2.      The test point should be over the cell RF conditions. (RSRP: higher than -70dBm, SNR: higher than 30).
3.      Connect the UEs to eNB. (Initial attachment)
4.      Run FTP client at the PC and Connect to the FTP server.
5.      Each UEs, start to download traffic with 5 FTP sessions.
6.      Measure the average data rate for 1 minute by DM or other tool and report the results.

1.1.1.3      Pass/Fail criteria

Ÿ The DL maximum cell throughput shall be higher than acceptable range.

1.1.2      UL Cell Throughput (Max.)

Name: UL Cell Throughput (Max.)
Purpose: To verify that a cell is supported maximum upload throughput
Measurement method
FTP is used, peak sector DL data rate shall be more than 0.95 x acceptable range
Acceptable range
More than 6.1Mbps.

1.1.2.1      Test conditions and requirements


Ÿ A laptop computer to monitor the UE and DM tool.
Ÿ A location for test condition (Cell Near link condition) shall be predetermined in the single Cell environment.
Ÿ There is no throughput limit on the FTP server and backhaul.
Ÿ System configuration is set to #2 UL - DL Configuration and #7 Special_subframe_configuration.
Ÿ UE and PC are supported maximum throughput. (no limit)
Ÿ If FTP is used, peak sector DL data rate shall be higher than 0.95 x acceptable ranges.

1.1.2.2      Test procedure

1.     Locate the test UE at a predefined place with near link condition in the single Cell environment.
2.      The test point should be over the cell RF conditions. (RSRP: higher than -70dBm, SNR: higher than 30).
3.      Connect the UE to eNB. (Initial attachment)
4.      Run FTP client at the PC and Connect to the FTP server.
5.      Start to upload traffic with 1 FTP session.
6.      Measure the average data rate for 1 minute by DM or other tool and report the results.

1.1.2.3      Pass/Fail criteria


Ÿ The UL maximum cell throughput shall be higher than acceptable range.

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