LTE Optimization

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HUAWEI TECHNOLOGIES CO., LTD. www.huawei.com Huawei Confidential Security Level: 22/6/8 LTE Optimization

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LTE Optimization

Transcript of LTE Optimization

Page 1: 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

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Contents

Network Optimization Processes

LTE Optimization Identity

KPI Formula

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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

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Network Optimization Flowchart

New site on air

Single siteverification

RF optimization

Service test and parameter optimization

Are KPI requirements met?

Yes

No

End

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Contents

Network Optimization Processes

LTE Optimization Identity

KPI Formula

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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.

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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

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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

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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.

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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

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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.

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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.

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Contents

Network Optimization Processes

LTE Optimization Identity

KPI Formula

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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

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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

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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

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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”

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