OG101 Planning for Radio Coverage Capacity

8/13/2019 OG101 Planning for Radio Coverage Capacity

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HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

HUAWEI Confidential

Security Level:

Planning for Radio

Coverage Capacity

Wireless Case & Training DepartmentISSUE 2.1


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HUAWEI TECHNOLOGIES CO., LTD. HUAWEI Confidential Page 2

The planning for the radio network mainly involves

coverage and capacity. The coverage planning

involves radio propagation and hardware model.

The capacity planning involves channel

configuration and location area planning. This

course describes the preceding contents.

Foreword


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Planning for coverage and capacity

Principles of selecting combiner-divider

Technology of improving coverage

Estimation of capacity

Planning for location area

After learning this course, you should be

familiar with:

Purpose


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Contents

Chapter 1 Radio Network Planning

Chapter 2 Radio Coverage Planning

Chapter 3 Radio Capacity Planning


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Radio Network Planning

The radio network planning consists of coverage planning and

capacity planning that are interactional.

Output

Single-BTS

capacity

Output

Single-BTS

configuration

Input

Subscriber

number/traffic

model

Input

Coverage

acreage/communica

tion probability

Capacity

planning

Coverageplanning

Output

Network

capacityOutput

BTS quantity


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Contents





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Contents

Section 1 Basic Knowledge of Radio

Coverage

Section 2 Solution of Radio Coverage


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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?


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HUAWEI TECHNOLOGIES CO., LTD. HUAWEI Confidential

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

1800M micro cells)

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

1800M cells)

Common propagation model


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Forecast of Coverage Distance


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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


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Solution of Radio Coverage

Product solution

Carrier power of macro

cell

Combiner-divider model

Micro cell

Antenna model

Technology of improving

coverage

Concentric cell

Extended cell

Diversity technology

Based on the product and technology, the radio coverage

solution contains:


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Product SolutionBased on environment and requirements of coverage target, the radio

coverage solution is used to choose combiner-divider units and BTSs.

For the specific selection principles and product features, refer to the

GSM BTS3.X Systemand GSM BTS3001/2C.


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Technology of Improving Coverage

Concentric-cell Technology

Timeslot extension technology

Diversity Technology


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Timeslot Extension Technology

Land

Ocean

Limited distance

specified in the

GSM protocol

Timeslot

extension

coverage

range


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Diversity Technology

Concept of diversity: Receiving several synthetic signals, and then combining the

signals

Function of diversity: Resisting the fast fading of channel efficiently

Category of diversity:

Combining modes of diversity signals:

Space diversity

Frequency diversity

Angle diversity

Polarization diversity

Selection combiner

Equal-Gain Combiner

Maximal-Ratio Combiner


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Concentric TechnologyAccording to the Timing Advance Index and receiver level threshold,

define the service area of OverLaid Subcell and UnderLaid Subcell.

The UnderLaid Subcell determines the coverage radius.

Use low-loss combiner in the UnderLaid Subcell to improve coverage.


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Question

What parameters are required in the

coverage planning?

How to select coverage schemeaccording to coverage requirements?


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Contents





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Contents

Section 1 Basic Knowledge of Capacity

Planning Section 2 Capacity Planning

Section 3 Location Area Planning

Section 4 Expanding Network Capacity


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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 asingle BTS and channel configuration data.

Description about Capacity Planning


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Capacity PlanningCase about Traffic Model

A B C

0.018 0.018 0.018 0.015 0.01548 48 48 40 4039 39 39 33 3357 57 57 47 471.35 1.35 1.35 1.35 1.3580% 80% 80% 80% 80%1.21 2.61 1.91 1.01 1.7120% 20% 20% 20% 20%1 1.7 1.7 1 1.70 0 0 0 00 0 0 0 010% 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 roamingRate of outgoing roaming

Call put-through rateNumber of location update in busy hours

Traffic model

Others

Number of sending messages in busy hours

Number 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


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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


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Capacity PlanningCase about Capacity Forecast

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

traffic): 15%

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

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

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

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.

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

15/3=5Erl.

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

channels: 10 channels/every cell

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


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Contents


Planning

Section 2 Capacity Planning




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Location Area Planning

As shown in the GSM protocol, the whole mobile communicationnetwork is divided into several service cells according to local area

codes.

The location area is the basic unit of paging cell in the GSM system.

In other words, the paging message is used in the location area.

The paging messages of a mobile subscriber are sent in all cells of

a location area.

The capacity of paging channel in a location area should be the

same.

In a location area, more than one BSC are allowed that should beconnected with one MSC.


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The size of the location area may affect the signaling traffic of

paging and location update. The impacts are described as follows:

If the location area is too large, the load of the PCH may be

heavy, the traffic on the Abis interface may be heavy, and the

system resource may be wasted.

If the location area is too small, the frequent location update may

lead to the congestion of signaling channel, the congestion of the

Abis interface, and the congestion of the A interface.

When supposing the traffic and channel configuration, first consider

the maximum number of TRX in a location area.

Division of location area


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If the 1800MHz frequency and 900MHz frequency have respective

MSCs, the location areas should be separated. Set parameters to

make mobile stations camp on the 1800MHz cell that absorbs traffic.

Reduce the number of dual-frequency handover and reselection.

When designing signaling channel, fully estimate the load of the

system owning to location update.

If the 1800MHz frequency and the 900 MHz frequency share a MSC,

use the same location area as long as the system capacity is

adequate at the early stage of network construction.

If the paging capacity is limited, set two location areas according to

geographic location or frequency band.

Division of Dual-frequency Network


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Dual-frequency network: Dividing location area in terms of frequency band


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Dual-frequency network: Dividing location area according togeographic location


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Contents


Planning

Section 2 Capacity Planning




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Expanding Network Capacity

At the early stage of Constructing GSM network, there are

restricted subscribers, a few of small BTSs are required for

the network capacity. Thus, the network coverage is more

important.

With increase of subscribers and development of new

services, congestion of cell becomes serious and network

quality is affected. Thus, the demand for network capacity is

more urgent.


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Process of capacity design

Mini-BTS Capacity expansion & Cell splitting Hot spot micro cell

Dual-frequency network

Methods of improving network capacity

Splitting cellular

Using Aggressive Frequency Reuse Pattern

Adding microcell equipment

Extending band


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At the early stage of constructing GSM network, wide coverage is

required. It has three features: highly-placed antennas, long

distances between BTSs, and large-coverage radius of cell.

With increase of subscribers, a cell is split into several small-

coverage cells.

To split a cell into several small-coverage cells, shorten the distance

between BTSs, reduce the height of antenna, or increase the tilt

angle of antenna. Based on cellular split, the BTSs, carriers, and channels increase. At

the same time, the traffic and allowable subscribers increase.

Cellular Splitting Principles


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Establish a new BTS at the midpoint of the connection between two BTSs.

Set of radius of original cell to the radius of new cell.

Do not change the antenna directions of split sectors.

Ensure that the space between two macro cell BTSs are not shorter than 400m.

Do not install antennas too high (proper height: 25m).

Lower the height of antenna when performing cellular splitting pattern if the

height is improper.

Cellular Splitting Pattern


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The microcell is required in the following two conditions:

Improving the situation of blind area

Lowering the traffic in the hot spots

The macrocell is at the lower layer and has a large coverage

acreage, so it can absorb most of traffic. The microcell is at the

higher layer and can improve indoor coverage. It absorbs the traffic

of hot spots and improves the quality of radio network.

Adding Microcell Equipment


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Extend band to add carriers of a cell and expand system capacity.

When the 900M band is fully used for bearing the GSM system, add the

1800M band to construct a dual-frequency network for traffic absorption.

Extending Band


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Questions

What data are required for capacityplanning?

What are principles and precautionsfor dividing location area?

For a new network, how to plancoverage and capacity and how to

obtain number of BTSs and that of

carriers?


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Thank You

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OG101 Planning for Radio Coverage Capacity