gsm radio coverage & capacity planning

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GSM Radio Coverage and Capacity

Planning

V 2.1

HUAWEI TECHNOLOGIES CO., LTD. HUAWEI Confidential

The planning for the radio network mainly involve

s coverage and capacity. The coverage planning i

nvolves radio propagation and hardware model. T

he capacity planning involves channel configurati

on and location area planning. This course descri

bes the preceding contents.

Foreword


• Planning for coverage and capacity

• Principles of selecting combiner-divider

• Technology of improving coverage

• Estimation of capacity

After learning this course, you should be

familiar with:

Purpose


Contents

Chapter 1 Radio Network Planning

Chapter 2 Radio Coverage Planning

Chapter 3 Radio Capacity Planning


Radio Network Planning

The radio network planning consists of coverage planning and

capacity planning that are interactional.

OutputSingle-BTS

capacity

OutputSingle-BTS

configuration

InputSubscriber

number/traffic model

Input Coverage

acreage/communication probability

Capacity planning

Coverage planning

OutputNetwork

capacity

OutputBTS quantity


Radio Network Planning

New-constructed

network

Reconstruction network

expanded network

Swapped network

Category of radio network:

Different networks require different input information and focuses.


Contents





Basic Knowledge of Radio Coverage

Basic knowledge of radio coverage:

• Balance of uplink and downlink

• Communication probability

• Propagation model

• Forecast for coverage distance


Balance of Uplink and Downlink

• Why the balance of uplink

and downlink is required?

• What are the factors that

may affect the balance of

uplink and downlink?


Communication Probability Concept of communication probability: Success call rate of MS on the

radio coverage border or in the cell

Category of communication probability: location probability and time

probability

In general, the time change has little impact on the communication probability,

so it can be neglected.


Propagation Model

Propagation model of free space (Lp=32.4+20logf+20logd)

Okumura-Hata model (Applying to forecast of 900M macro cell)

COST231-Hata model (Applying to forecast of 1800M macro cell)

COST231 Walfish Ikegami model (Applying to forecast of 900M and 18

00M micro cells)

Indoor propagation model (Keenan-Motley, applying to 900M and 1800

M cells)

Common propagation model


Forecast of Coverage DistancePrinciples

1. According to the communication

probability, obtain the receiving

level median.

2. According to the balance of

uplink and downlink, estimate the

maximum path loss.

3. According to the features of

environment, confirm the

propagation model.

4. Forecast the coverage distance

of cell.


Forecast of Coverage Distance


Forecast of Coverage DistanceCase

To construct a 900MHz Network in the suburb that requires about

100 square kilometer coverage acreage, -94dBm minimum

receiving level, and 91% border coverage probability, forecast the

coverage distance and calculate the required quantity of BTSs.

Useful input information• Band: 900MHz• Network environment: suburb • Coverage acreage: 100km2

• Efficient receiving level: -94dBm• Border coverage probability: 91 ％


Forecast of Coverage DistanceFrequency

Environment

Probability

Level

Required BTS quantity

Coverage acreage

Coverage radius


Question

What parameters are required in the coverage planning?

How to select coverage scheme according to coverage requirements?


Contents





Contents

Section 1 Basic Knowledge of Capacity Planning

Section 2 Capacity Planning

Section 3 Location Area Planning

Section 4 Expanding Network Capacity


Basic Knowledge of Capacity PlanningFor the capacity planning, you need to know about the following basic concepts:

Traffic

Call exchange volume of a subscriber in a particular ti

me

Another name: traffic load ; Unit: Erlang;

Busy-hour traffic per subscriber: A=α•ｔ

Call loss rate (service grade)

When all the channels of a system are occupied, use t

he following formula to calculate call loss rate:


Basic Knowledge of Capacity PlanningErlang-B


Capacity Planning

According to the number of subscribers, traffic model, and local economic

situations, forecast network traffic.

According to the number of BTSs, obtain the average traffic load of a single BTS

and channel configuration data.

Description about Capacity Planning


Capacity PlanningCase about Traffic Model

A B C

0.018 0.018 0.018 0.015 0.015

48 48 48 40 40

39 39 39 33 33

57 57 57 47 47

1.35 1.35 1.35 1.35 1.35

80% 80% 80% 80% 80%

1.21 2.61 1.91 1.01 1.71

20% 20% 20% 20% 20%

1 1.7 1.7 1 1.7

0 0 0 0 0

0 0 0 0 0

10% 10% 10% 10% 10%

10% 10% 10% 10% 10%

100% 100% 100% 100% 100%

Mobile-Mobile 40% 40% 40% 30% 30%

Fixed-Mobile 36% 36% 36% 38% 38%

Mobile-Fixed 24% 24% 24% 32% 32%

Rate of incoming roaming

Rate of outgoing roaming

Call put-through rate

Number of location update in busy hours

Traffic model

Others

Number of sending messages in busy hoursNumber of receiving messages in busy hours

Items

Busy-hour traffic per subscriber

Call rate

Rate of secondary paging

Number of handover per call

Average call duration

Calling quantity Called quantity

Number of calls in busy hours

Rate of activation


Capacity Planning

A local network will be constructed. After two years, the

number of subscribers may attain 100,000. Provide that the

traffic per subscriber is 0.02Erl, 120 BTSs are required, and

the call loss rate is 2%.

Case about Capacity Forecast

Useful information• Subscriber quantity: 100,000• Call loss rate: 2%• Traffic model: 0.02Erl• Number of BTSs: 120


Capacity PlanningCase about Capacity Forecast

① Roaming factor (traffic and developing trend): 10%; dynamic factor (burst traffi

c): 15%

Network capacity: 10×(1+10%+15%)=125000

① In terms of congestion, use 85% to calculate the bearer capability for traffic. T

hus, the design capacity of network is: 12.5/(85%)=147100, that is 150000.

② According to the provided traffic model, that is average 0.02Erl traffic, forecast

the busy-hour traffic of the whole network: 150000 ×0.02=3000Erl.

③ The average traffic per BTS is: 3000/120=15Erl, average traffic per cell: 15/3=

5Erl.

④ Based on 2% call loss rate, query the Erlang-B to find the number of voice ch

annels: 10 channels/every cell

⑤ The number of control channels: 12 channels/every cell, 2TRX/every cell


Questions

• What data are required for capacity planning?

• For a new network, how to plan coverage and capacity and how to obtain number of BTSs and that of carriers?

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gsm radio coverage & capacity planning

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