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
Conceptual Frame work
Design Case Presentation
Outline
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Conceptual Frame work
Coverage planning principles
Capacity planning principles
Frequency planning principles
Radio Network Parameters planning principle
Radio Network Optimization Principle
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Conceptual Frame work
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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Conceptual Frame work
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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Conceptual Frame work
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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Conceptual Frame work
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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Conceptual Frame work
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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Conceptual Frame work
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
Conceptual Frame work
Design Case Presentation
Outline
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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
Capacity Target
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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
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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Design Case Presentation
Figure RSCP simulation
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Design Case Presentation
Figure EcIo simulation
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Thank you
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