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Success Story

By Zou Yizhi, Qu Chengfu, Shi Jianqiang

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By optimizing the GSM network,

Guiyang Mobile (a branch of China

Mobile) improved the networkquality, balances network load,

realized E2E optimization, realized fast

subscriber growth and user perception

improvement, and successfully built a

network based on customer perception.

With the implementation of Western China

Development, the city of Guiyang sees a

rapid development in economy, culture,

science & education, transportation, and

telecommunications elds. As the spearhead

of communication in Guizhou province,

Guiyang Mobile has also continuously

accelerated the construction of mobile

telecommunications networks and is

committed to improving services and

boosting corporate image.

Guiyang city is located at Karst hilly

areas featuring complex landforms and

the relative altitude difference in city

areas reaches 100 meters. Due to the

concentration of users in down town areas,

densely distributed sites, large number of

narrow alleys, multi-layer in-building service

(IBS) distributions, and dense residential

areas in urban areas, users raise increasingly

higher requirements for coverage. In

addition, the single coverage type cannot

satisfy the complex and changing urban

environment. Tariff policy adjustment

drives the rapid development of diversied

services, causing a sharp increase in trafcvolume in some areas. In this way, network

bearer capacity is facing great challenges

and network structure in some areas needs

to be optimized. The requirements for

network quality, capacity, and coverage are

increasingly higher. Therefore, forging a

top-quality GSM network is top priority for

Guiyang Mobile.

To quickly improve the current network

status in Guiyang, Guiyang Mobile, together

with the SmartCare solution of Huawei,

proposed a principle of "Determining

Network Landscape, Eliminating Network

Quality Problems, and Improving User

Perception" to comprehensively improve

network quality after in-depth analysis

of networking, trafc, and geographical

conditions. In addition, Guiyang Mobile

adopted the following methods to realize

coordinated multi-product optimization,

FEB 2012 ISSUE 31

29 <



Success Story

(Idea of the stereoscopic network integrating GSM900 with DCS1800)

900M sites in the two metropolitan areas are of high density. The frequencies have high reuse rate and high

frequency interferences, which brings tremendous challenges to the effective utilization of existing wireless

network resources. To reduce the inter-frequency interferences, balance traffic load, and optimize network

coverage, it is required to optimize the structure of the existing network. By building a dual-plane and

tridimensional IBS system, we can make full use of the 1800M resources and resolve the problems facing the

existing network once and for all by optimizing the two networks.

Cover older uptown and dense street by Street site

IBS1800M

Plane1: 900M

Plane2: 1800M

Tridimensional IBS

Tridimensional coverage (over 15F)Larger capacityHigher speed

Continuous coverage

of double plane

Continuous coverageLarger capacityHigher speed

(After the idea of the stereoscopic network is implemented, KPIs such as trafc

proportion, coverage of backbone roads, and speech quality are fully improved.)

By the end of July 2011, the project team successfully implemented thephase-1 & phase-2 frequency E network retirement project. By then, 1281800M macro sites totaling 1752 carrier frequencies and 42 1800M IBSsites totaling 158 carrier frequencies have been added to the network.The proportion of 1800M sites was increased from 33.48% to 40.95%on a year-on-year basis.

Continuously balance the load on 900M/1800M sites in the twometropolitan areas and customize the scenario switchover and parameterre-selection solution according to the actual situation in Guiyang to ensurethat the 1800M sites can effectively share the traffic. The proportion oftraffic absorbed by 1800M sites was increased from 28.81% to 43.70 ona year-on-year basis.

80.00%

60.00%

40.00%

20.00%

0.00%1800M Carrier Accounting 900M Carrier Accounting

2010.6 2011.6

40.95%33.48%

66.52%59.05%

80.00%

60.00%

40.00%

20.00%

0.00%1800M Voice Traffic Accounting 900M Voice Traffic Accounting

2010.6 2011.6

43.70%

28.81%

71.19%

56.30%

With the increase of 1800M sites, number of sites with high traffics isreduced, as well as the frequency interference. As a result, the voiceservice quality increased from 95.69% to 98.21% on a year-on-year basis.

Continuously improve the network coverage on roads. Because 1800Mfrequency has abundant resources and high voice service quality, 1800Mresources are generally used for improving the drive test result. Thecoverage of 1800M network was increased from 27% to 54.70% on ayear-on-year basis.

80.00%

60.00%

40.00%

20.00%

0.00%1800M Coverage Accounting

(Main Road)900M Coverage Accounting

(Main Road)

2010.6 2011.6

54.70%

27.00%

73.00%

45.30%

99.00%

98.00%

97.00%

96.00%

95.00%

94.00%

2010.6 2011.6

98.21%

95.69%

Voice Quality

located the problem points through a

large number of routine tests, complaint

handling, trafc maps, and coverage

prediction. In this way, Guiyang Mobile sets

up sites in areas where coverage is required,

improving coverage depth. To share thetrafc load on GSM900 networks, Guiyang

Mobile accelerated the construction of

entering the phase of fully improving

network quality.

1. Integrating GSM 900 Networks with

DCS1800 Networks

In view of the development requirements

of dual-band networks, Guiyang Mobile

DCS1800 networks to achieve continuous

coverage, laying a foundation for

reducing the number of sites with higher

conguration requirements and alleviating

frequency interference. In addition,

Guiyang Mobile exibly deployed sites onstreets or used remote radio units (RRUs)

to achieve coverage in multiple scenarios

instead of the original coverage by one

macro site. General packet radio service

(GPRS) and Enhanced Data rates for GSM

Evolution (EDGE) channels were enabled

on GSM900/DCS1800 MHz bands. In this

way, mobile stations (MSs) can initiate data

services at any frequency band, therefore

balancing the network load, reducing the

number of handovers between GSM900

and DCS1800 MHz bands, and improvinguser perception.

With the continuous exploration of the

stereoscopic network, by the end of July

2011, the proportion of DCS1800 MHz

carrier frequencies increased from 33.4%

in the same period in 2010 to 40.95%, and

key performance indicators (KPIs) such as

trafc proportion, coverage of backbone

roads, and speech quality were fully

improved.

2. Integrating the IBS Network with theStereoscopic Network

The increasing special locations in

urban areas, such as high buildings and

underground parking garages have

become a huge problem for outdoor

coverage. Facing the problems of increased

complaints about indoor connectivity on

the live network and an increasing number

of complaints about poor coverage in

small areas, Guiyang Mobile and Huawei

project team actively investigated the areaswhere the problems occur frequently and

adopted the stereoscopic coverage to

resolve the problems according to actual

local conditions. For VIP sites and high-

grade ofce buildings, Huawei IBS solution

was adopted to properly allocate sufcient

radio resources, therefore achieving

optimum coverage effects and improving

VIP customer satisfaction. For areas where

the capacity of outdoor sites failed to satisfy

the heavy trafc, such as stations, shopping

malls, and schools, IBS sites were set up to

absorb as many trafc as possible. By doing

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this, outdoor sites load was reduced, and

the impacts of trafc peaks on the entire

network were alleviated, ensuring the voice

quality of outdoor sites.

After the IBS project (Phase III) was

implemented, KPIs such as network radio

access, handover success rate, TCH call

drop rate, HQI, and interference band were

improved to varying degrees. Wherein, the

improvement of HQI and interference band,

1% and 5% respectively, was the most

evident.

3. Integrating the 2G Network with the

3G Network

If the 3G network shares the same

IBS system with the 2G network, the

bandwidth of the existing 2G IBS system

needs to be transformed; otherwise, the

3G indoor coverage network needs to be

designed again. Therefore, compatibility,interference, service bearer and sharing,

and capacity need to be fully considered

during the design of the 2G IBS system.

In addition, the Wireless Local Area

Network (WLAN) and WiFi terminals are

used in hotspot areas. For areas where

point-to-point (P2P) trafc takes a higher

proportion, the WLAN is deployed

preferentially. For areas on the 3G

network where absorption of data services

is insufcient, coverage is enhanced

and price leverage is used to drive the

development of data services.

With the implementation of a series of

optimization schemes to improve connectivity

and ultimately gain better user perception,the number of exceptions on the live network

decreases signicantly from 217 in January

2011 to 80 in July 2011. In June 2011, the

number of static users exceeded 20,000,000,

which is another milestone for Guiyang Mobile

after the number of static users exceeded

10,000,000 in 2008. In addition, network

quality of Guiyang Mobile ranks higher among

peers nationwide and the user penetration

rate in Guizhou province exceeds 75%. In the

preventive maintenance inspection of China

Mobile held in December 2010, Guiyang

Mobile surpasses other competitors.

FEB 2012 ISSUE 31

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