Ch1_Introduction to RF Planning

CP15 RF Planning Fundamentals

Chapter 1 Introduction to RF Planning

Objectives

•

Describe basic GSM RF Planning and optimisation.

•

List the important characteristics of a good RF plan.

•

List the basic steps involved in Cell/RF planning.

•

Prepare a single Power Budget for both uplink and downlink

Basic Planning Process

Optimisation Process

Subscriber Distribution

Table 1-1 Subscriber Distribution Area Type

Traffic % Erlangs Subscribers

1/1/1 Sites

2/2/2 Sites

Urban  High density

20

50

2000

6

2

Urban

30

75

3000

9

3

Industrial

15

37.5

1500

5

2

Suburban

25

62.5

2500

8

3

Highways

5

12.5

500

2

1

Quasi-open

5

12.5

500

2

1

100

250

10000

32

12

 –

Totals CP15_ch1_03

Link Budget Table 1-2 RF Link Budget UPLINK

DOWNLINK

MS

BTS

33dBm

43dBm

Body Loss

3dB

0dB

Combiner Loss

0dB

0dB

Feeder Loss

0dB

1.5dB

Connector Loss

0dB

2dB

Tx Antenna Gain

0dB

17.5dB

30dBm (A)

57dBm (C)

TRANSMITTING ENTITY Tx RF Output Power

EIRP

CP15_ch1_04

Link Budget Table 1-2 RF Link Budget (cont’d) UPLINK

DOWNLINK

BTS

MS

-107dBm

-102dBm

17.5dB

0dB

Diversity Gain

3dB

0dB

Connector Loss

2dB

0dB

1.5dB

0dB

Interference Degradation Margin

3dB

3dB

Body Loss

0dB

3dB

Duplexer Loss

0dB

0dB

-121dBm

-96dBm

4dB

4dB

Required Isotropic Power

-117dBm (B)

-92dBm (D)

Maximum Permissible Path Loss (MPL)

147dB (B-A)

149dB (D-C)

RECEIVING ENTITY Rx Sensitivity Rx Antenna Gain

Feeder Loss

Rx Power Fade Margin

CP15_ch1_05