LTE Optimization
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Transcript of LTE Optimization
HUAWEI TECHNOLOGIES CO., LTD.
www.huawei.com
Huawei Confidential
Security Level:
英文标题 :40-47pt
副标题 :26-30pt
字体颜色 : 反白内部使用字体 :
FrutigerNext LT Medium
外部使用字体 : Arial
中文标题 :35-47pt
字体 : 黑体 副标题 :24-28pt
字体颜色 : 反白字体 : 细黑体
23/4/17
LTE Optimization
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 2
Contents
Network Optimization Processes
LTE Optimization Identity
KPI Formula
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 3
Network Optimization Methods
Network optimization involves adjustment of azimuths, tilts, antenna height, eNodeB
transmit power, feature algorithms, and performance parameters. Optimization methods in
different standards are similar, but each standard has its own measurement definition.
Network Optimization
Azimuth AdjustmentTilt Adjustment
Feature Configuration
Reselection and Handover Parameter Adjustment
Power Adjustment
Antenna Height
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 4
Network Optimization Flowchart
New site on air
Single siteverification
RF optimization
Service test and parameter optimization
Are KPI requirements met?
Yes
No
End
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 5
Contents
Network Optimization Processes
LTE Optimization Identity
KPI Formula
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 6
Single site verification
Single site verification will focus on data server more than anything else:
throughput test
Ping delay test
General test should be done, such as handover, signal distribution and
so on.
Note: For the throughput test, UDP is more suitable than TCP; because
TCP’s send windows always change, that will affect the test result.
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 7
SSV Troubleshooting
Poor coverage; Low SINR;
RB is not enough; QoS is wrong;
Transmission is not enough;
Terminal have not ability
Poor coverage;
Low SINR;
Transmission quality is bad;
QoS is wrong
Low throughput
Ping delay
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
RF optimization
Difficulty: Share the antenna with 2/3G;
Frequency reuse 1, sensitivity for the interference
Difference: RSRP: Reference signal received power;
Power adjustment: PA/PB
Page 8
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
RF Optimization Difficulty
Share the antenna with 2/3G Use special antenna, which have separate control part
between 2G/3G and LTE, and can be remote controlled.
Sensitivity for the interference Because LTE reuse the frequency by 1, cross coverage
should be the main problem for RF optimization. Try to
control the network topology is more important than the
others.
Page 9
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 10
RSRP
Note: Different from WCDMA systems, LTE systems have multiple subcarriers multiplexed.
Therefore, the measured pilot signal strength is the RSRP of RE(resource element) not the
total bandwidth power of the frequency.
Reference signal received power (RSRP), is determined for a
considered cell as the linear average over the power
contributions (in [W]) of the resource elements that carry cell-
specific reference signals within the considered measurement
frequency bandwidth.
3GPP definition
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 11
Power Adjustment Method
Service power configuration (calculating PDSCH power based
on RS power)
RS power PA and PB are delivered using RRC signaling. For
two antennas, PA is ρA and ρB is calculated based on the right
table. PDSCH power is calculated based on PA and PB.
Currently, it is recommended that PB be set to 1 dB and PA be
set to -3 dB. That is, the pilot power for symbols including pilot
symbols accounts for 1/3. This setting optimizes network
performance and ensures that the pilot power for Type A and
Type B symbols is equivalent to the service channel power. In
scenarios with special requirements, for example, in rural
scenarios requiring low edge rates, PB can be set to 2 or 3 dB to
enhance coverage.
Subcarriers share the transmit power of an eNodeB, and therefore the transmit power
of each subcarrier depends on the configured system bandwidth (such as 5 MHz and 10
MHz). A larger bandwidth will result in lower power of each subcarrier. LTE uses PA and
PB parameters to adjust power.
ρA: indicates the ratio of the data subcarrier power of OFDM symbols excluding pilot
symbols to the pilot subcarrier power.
ρB: indicates the ratio of the data subcarrier power of OFDM symbols including pilot
symbols to the pilot subcarrier power.
Definitions in 3GPP specifications
Control channels
Power of PDCCHs, PHICHs, PCFICHs,
PBCHs, primary synchronization channels,
and secondary synchronization channels is
set using an offset from RS power.
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
Handover
No RNC/BSC, When an eNB cell is configured as neighbor cells
of other eNBs, external cells must be added first;
System send the frequency information to the terminal instead of
neighbor cells list, terminal scan the frequency quality and feed
back to eNB, the system will choose the target eNB.
Page 12
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 13
Contents
Network Optimization Processes
LTE Optimization Identity
KPI Formula
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
Network KPI
Service setup success rate =
Number of service setup success/number of service
setup attempt*100% >=98% 1) Service setup attempt: the RRCConnectionRequest for the
data service(exclude the RRC request for other reason) 2) Service setup success: UE response the
RRCConnectionReconfigurationComplete message after
receiving the RRCConnectionReconfiguration message
Page 14
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
Network KPI
Call drop rate =
number of service drop/number of total service
connection*100% 1)Number of total service connection: number of UE receives
Alerting while service request 2)Number of service drop: A: If without NAS message indicate DRB release UE receivers air
interface RRCConnectionRelease; B: UE is in service procedure and transfer status from connected
mode to idle mode without receiving RRCConnectionRelease
Page 15
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
Network KPI
Handover success rate =
Number of handover success/Number of handover
attempts* 100% 1) Number of handovers success: the UE send an
RRCConnectReconfigurationComplete message to T-eNodeB
2) Number of handover attempts: if RRCConnectionReconfiguration
messages includes “mobilityControlInfo”, plus 1 in number of HO
Page 16
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
Service KPI
Uplink throughput Observe by the test tool, e.g. Netmeter
Downlink throughput Observe by the test tool, e.g. Netmeter
Ping delay Stat. average value from sending “PING Request” to receiving
“PING Reply”
Page 17
Thank youwww.huawei.com