digital fitsum mergia 1096

7/28/2019 Digital Fitsum Mergia 1096

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Prepared by Fitsum Mergia

April 6 2013

Addis Ababa

Ethiopia


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Introduction

Conceptual Frame work

Design Case Presentation

Outline


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IntroductionThe objective of RF planning is to build a cellular system that providessufficient coverage and capacity, meets the quality requirementsand allows for future system growth. All this must be accomplishedusing a limited number of network elements and radio frequencies.

What is RF planning ?

Coverage

Capacity

Quality of service

Cost


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IntroductionWhat are the major activities involved in the RF-planning process?


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IntroductionSTEP 1: TRAFFIC AND COVERAGE ANALYSIS (SYSTEM REQUIREMENTS)

The cell planning process starts with traffic and coverage analysis.

The analysis should produce information about the geographical

area and the expected need of capacity. The types of data

collected are:Cost

Capacity

Coverage

Grade of Service (GoS)

Available frequencies

Bit Error Rate (BER)

System growth capacity

Bit Error Rate (BER)

System growth capability


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IntroductionSTEP 2: NOMINAL CELL PLAN

Upon compilation of the data received from the traffic and

coverage analysis, a nominal cell plan is produced. The nominal

cell plan is a graphical representation of the network and simply

looks like a cell pattern on a map.

However, a lot of work lies behind it .Nominal cell plans are the first cell plans and form the basis for further planning.At this stage, coverage and interference predictions are usually started.

Such planning needs computer-aided analysistools for radio propagation studies.


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IntroductionSTEP 3: SURVEYS (AND RADIO MEASUREMENTS)

It is necessary to assess the real environment to determine whetherit is a suitable site location when planning a cellular network, since

even better predictions can be obtained by using field

measurements of the signal strengths in the actual terrain where

the mobile station will be located.

Radio measurements are performed at the sites where the radioequipment will be placed.


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IntroductionSTEP 4: (FINAL CELL PLAN) SYSTEM DESIGN

Once we optimize and can trust the predictions generated by the

planning tool, the dimensioning of the BTS equipment, BSC, and

MSC is performed. The final cell plan is then produced.

STEP 5: IMPLEMENTATION

System installation, commissioning, and testing are performed

following final cell planning and system design.


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IntroductionSTEP 6: NETWORK OPTIMIZATION

After the system has been installed, it is continually evaluated to

determine how well it meets the demand. This is called network

Optimization.

Optimization involves:

Checking that the final cell plan was implemented successfully

Evaluating customer complaints

Checking that the network performance is acceptable

Changing parameters and performing other measures (if needed)


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Introduction



Outline


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Coverage planning principles

Capacity planning principles

Frequency planning principles

Radio Network Parameters planning principle

Radio Network Optimization Principle


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The target for coverage planning is to find optimal location for

base stations to build continuous coverage according to the

planning requirements .Especially in the case of a coverage

limited network the BTS location is critical.

Coverage planning principles

Link budgetTo guarantee a good radio link quality in both directions (uplink and

downlink) the power of BTS and MS should be in balance at the edge of

the cell. The main idea behind the power budget calculations is to

receive the maximum output power level of BTS transmitter as a function

of BTS and MS sensitivity levels, MS output power, antenna gain (Rx & TX),

diversity reception, cable loss, combiner loss, etc.


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Propagation model

The propagation model is the basis for planning the mobile

communication cells. The propagation model can ensure precision and

save manpower, cost, and time. A good mobile radio propagation

model can perform adjustment according to different landforms, such

as plain, hill, and valley or according to different habitation

environment, such as open area, suburb, and city.

Examples of propagation Model . Long-distance Longley-Rice

Okumara Hata Cost 231-Hata Wolfish-Ikegami

cost 231

Wolfish-Xia JTC XLOS (Motorola

proprietary model) Bullington Universal Model Etc..


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Capacity planning principlesThe objective of capacity estimation is to estimate site number

based on Traffic model and service volume required.In CDMA system, capacity is restricted by interference in the

uplink and transmission power in downlink. Whereas in FDMA/TDMA system the number of traffic channel will be a restrictive

factor in capacity planning.


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Frequency planning principles

The main goal of the frequency-planning task is to increasethe efficiency of the spectrum usage, keeping the interferencein the network below some predefined level. Therefore it isalways related to interference predictions.


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Radio Network Parameters planning principle

Defining the radio network parameters is the final step in the design of a

radio network. There are a number of parameters that has to be

specified for each cell. The parameters could be divided into four

different categories, namely:Common cell data

Example: Cell Identity, Power setting, Channel numbersNeighboring cell relation data

Example: Neighboring Cell relation, Hysteresis, Offset Locating and idle mode behavior

Example: Paging properties, Signal strength criteria, Quality

thresholds Feature control parameters

Example: Frequency Hopping and Dynamic Power Control


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Radio Network Optimization Principle

Radio Optimization is a process involving analysis of traffic data

collected by the system to better adjust the system to the actual traffic

demand distribution.

Adjustments that can be made include: Changing handover parameters to move traffic from a congested

cell to a neighboring cell with a low traffic load

Changing switch parameters to optimize the traffic handling

capacity of the system

Adding cells or adding radio channels to congested cells and/or

reducing the number of radio channels in cells with lower traffic than

expected


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Introduction



Outline


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Overview of WCDMA network planning principlesCapacity Estimation Principle

Coverage Planning EstimationThe goal of coverage estimation is to obtain the quantity and

configuration of the sites using link budget, and to fulfill the

coverage requirements, such as coverage area, coverage rate,

indoor coverage, cell load, and etc.

According to the traffic model and available channels per cell,

the subscribers supported by one cell can be calculated;

therefore the number and configuration of these sites can be

obtained on the basis of total subscribers.


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Capacity Estimation Principle

The WCDMA network supports many services at the same time. As aresult, the evaluation of cell capacity in the WCDMA networkcannot simply follow the evaluation method used for the networkonly supporting the voice service,

For this reason, capacity evaluation is based on the mixed servicecapacity evaluation method of the Campell theory.


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Campell theory.

The fundamental principle of Campbells Theorem is that all services

are equivalent to a virtual service by certain rules, and calculatetotal traffic (Erl) of this virtual service, then calculate the number ofvirtual channel satisfying required traffic, calculate the number ofactual channel satisfying network dimensions.


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Campbells equivalency model principle:

Where C capacity factorVariance variance of mixed services

Mean mean of mixed servicesamplitudeservice amplitude of service i

Cservice number of required channel of service iVirtual_erlang traffic of virtual services

Virtual_channel Number of required virtual channel satisfying virtualtraffics.


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Coverage Planning Estimation:

Among all the communication propagation environments, the wirelesscommunication environment is the worst and most complex one, whichis affected by slow fading and multi-path propagation in addition to thepath loss of free space, thus resulting in space selective fading, timeselective fading, frequency selective fading and other symptoms, and

greatly degrading the uplink/downlink received signal quality.selection of a propagation model close to the actual environment in

the radio network design is the basis for coverage planning and

prediction emulation.


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Radio propagation modelThe propagation model describes the average signal propagation in

certain environment. It often denotes the path loss as a function of

distance of separation between a transmitter and receiver.

Cost231-Hata Propagation model formula:Path loss = k1 + K2 log d + k3 (Hms) + k4 log Hms + k5 log Heff + k6 log Heff log d +

k7*Diffn + C_loss


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Path loss = k1 + K2 log d + k3 (Hms

) + k4 log Hms + k5 log Heff + k6 log Heff log d +

k7*Diffn + C_lossWhere

d Distance from the base station to the mobile station (km).Hms Height of the mobile station above ground (m).Heff Effective base station antenna height (m).Diffn Diffraction loss calculated using Epstein,K1 Interceptk2 Slopek3 Mobile antenna height factor. Correction factor used to

take into account the effective mobile antenna height.k4 Okumura-Hata multiplying factor for Hms.k5 Effective Antenna Height Gain. This is the multiplying

factor for the log of the effective antenna height.k6 This is the Okumura-Hata type multiplying factor for

log(Heff)log(d)k7 Multiplying factor for diffraction calculations

C_loss Clutter specifications such that heights and separation arealso taken into account in the calculation process


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Case Background

In year 2010 ZTE Cooperation on the interest of Ethio telecom built a

UMTS network that cover the whole Addis with a network capacity

of 300,000 users.

In this section the planning approach that ZTE cooperation followed

to deploy the UMTS network is briefly described.


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Capacity TargetThe capital Addis Ababa is guaranteed continuous coverage for all

services with 300,000 WCDMA subscribers over dense area and urban

area according to GSM network coverage boundary. The dense area is

56 km2 with 126,800 users, and the urban area is 275.6 km2 with 173,200

users.


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Capacity Target


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Coverage target

In order to ensure the network quality, the following KPI requirements has

been set:

Coverage KPI Requirements:

Dense Urban & Urban: RSCP: >=95% > -85dBm (outdoor on street)

Dense Urban & Urban: Ec/Io >=95% >-10db

Traffic Model

Traffic model is a tool through which the statistical traffic characteristic of

the network being designed is understood .The modeling is done based on

past experience and also future requirement.


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Traffic Model

Items ProportionData throughput

per user (bps)

Circuit Switch Voice penetration ratio 100%

Circuit Switch data penetration ratio 20%

Voice Traffic per CS voice sub per BH(Erl) 0.025

CS data traffic per Circuit Switch (CS) data sub(Erl) 0.002

Packet switch Penetration Ratio 100%

Total PS throughput (HSDPA+, HSUPA and R99 UL+DL)per PS Sub (bps) 3000 3000

Proportion of Uplink PS throughput 13.60% 408

Proportion of downlink PS throughput 86.40% 2592

R99 share of Downlink PS throughput per sub 16% 408

HSDPA+ share of Downlink PS throughput per sub 84% 2184

R99 share of UL PS throughput per sub 40% 163

HSUPA share of UL Packet (PS) throughput per sub 60% 245

Service Model Type Erl Per user GOS Penetration Rate

Voice 0.025 2% 100%

CS 64 0.002 2% 20%

UL Throughput Per

user

DL Throughput Per

user

[kbps] [kbps]

PS 64/64 0.102 0.102 100%

PS 64/128 0.0436 0.17 100%

PS 64/384 0.0176 0.136 100%

Allocated Power [w]Data Throughput

Per User [kbps]Penetration Rate

HSDPA+ 0 2.184 100%

Data Throughput Per

User [kbps]Allocated UL Load Penetration Rate

HSUPA 0.2448 0% 100%

Carrier Number

Penetration Rate

1


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Different services throughput distribution calculationTotal PS throughput= Uplink + Downlink throughput

3000bps= 3kbps=0.102+0.102+0.0436+0.17+0.0176+0.136+2.184+0.2448o HSDPA+ Throughput Per User [kbps]= 3.0*86.4%*84%=2.184kbpso HSUPA Throughput Per User [kbps]=3.0*13.6%*60%=0.2448kbpsR99 PS service throughput Ratio is obtained to the best of ZTEs experience.o Totally R99 PS throughput Downlink=3.0*86.4%*16%=0.408kbps Downlink Ratio for [PS64/64: PS 64/128: PS 64/384] =[0.250.4166667

0.3333333] 0.408*DL Ratio=[0.1020.170.136]


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o Totally R99 PS throughput Uplink=3.0*13.6%*40%=0.1632 Uplink Ratio for PS64/64: PS 64/128: PS 64/384 =[0.6250.2671569

0.1078431] 0.2448*UL Ratio=[0.1020.04360.0176.]


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Network planning outputsBased on the combination of the coverage scale estimation and

capacity scale estimation result the number of sites are different from

one scale to another. From the coverage aspect, the numbers of sites

are 220 S111. But, from the capacity aspect, the numbers of sites are

284 S111. According to the network scale estimation theory, it isnormal practice to choose the larger one as the final result. Therefore,

the capital city needs 220 S111 and 32 S222 sites in total including

existing 50 sites.


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Addis Ababa Coverage result

Dense urban 82 (S1/1/1) 59 (S1/1/1) 32 (S2/2/2)

urban 138(S1/1/1)

total

Capacity result

161(S1/1/1)

220 (S1/1/1) + 32 (S2/2/2)

And the average downlink throughput per sector will be around 4-

4.5Mbps for S111 and 8-9Mbps for S222 based on ZTEs HSDPA+

commercial network experience. The average subscriber per site in

DU is 1030 for S111 and 2060 for S222,


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Figure RSCP simulation


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Figure EcIo simulation


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Thank you

digital fitsum mergia 1096

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