wireless engineers in the radio world

7/27/2019 Wireless Engineers in the Radio World

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February 23, 2006

THE Wireless ENGINEER

IN THE RADIO WORLD

HUAWEI TECHNOLOGIES CO., LTD.

PREPARED BY :

Efosa Aigbe


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Part I - Content

Basics

Basic Building Blocks of an RF System

RF Parameters and RF MeasurementEquipment

Support / getting started


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dBm to Watt

About dBm and W Voltage Ratio aV = 20 log (P2/P1) [aV] = dB Power Ratio aP = 10 log (P2/P1) [aP] = dB Voltage Level V = 20 log (V/1V) [V] = dBV Power Level P = 10 log (P/1mW) [P] = dBm e.g. 25mW max. allowed radiated power in the

EU SRD band>> P = 10 log (25mW/1mW) = 10 * 1,39794dBm >> 14 dBm


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See http://www.ncc.gov.ng/index.php?option=com_content&view=article&id=84&Itemid=98For Nigerias Spectrum allocation.
http://www.ncc.gov.ng/index.php?option=com_content&view=article&id=84&Itemid=98http://www.ncc.gov.ng/index.php?option=com_content&view=article&id=84&Itemid=98http://www.ncc.gov.ng/index.php?option=com_content&view=article&id=84&Itemid=98http://www.ncc.gov.ng/index.php?option=com_content&view=article&id=84&Itemid=98


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RF Communication Systems

Simplex RF System

* A radio technology that allows only one-way communication from a

transmitter to a receiver

* Examples: FM radio, Pagers, TV, One-way AMR systems

Half-duplex RF Systems

Operation mode of a radio

communication system in which each

end cantransmit and receive, but not

simultaneously.

Note: The communication is

bidirectional over the same frequency,

but

unidirectional for the duration of amessage. The devices need to be

transceivers. Applies to most TDD and

TDMA systems.

Examples: Walkie-talkie, wireless

keyboard mouse


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Full-duplex RF SystemsRadio systems in which each end can transmit and receive simultaneously

Typically two frequencies are used to set up the communicationchannel.

Each frequency is used solely for either transmitting or receiving.

Applies to Frequency Division Duplex (FDD) systems.

Example: Cellular phones, satellite communication


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Wireless Communication Systems


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Modulation and Demodulation


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Modulation Methods

Starting point:

we have a low frequency signal and wantto send it at a high frequency

Modulation: The process ofsuperimposing a low frequencysignal onto a high frequency signal

Three modulation schemes available:

1. Amplitude Modulation (AM): theamplitude of the carrier varies inaccordance to the informationsignal

2. Frequency Modulation (FM): thefrequency of the carrier varies inaccordance to the information signal

3. Phase Modulation (PM): the phase ofthe carrier varies in accordance tothe information signal.

Digital Modulation

Modulation of digital signals isknown as Shift Keying

Amplitude Shift Keying (ASK):

Pros: simple

Cons: susceptible to noise

Example: Many legacy wireless

systems, e.g. AMR


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Frequency Shift Keying (FSK):

Pros: less susceptible to noise

Cons: theoretically requires larger

bandwidth/bit than ASK

Popular in modern systems

Gaussian FSK (GFSK), e.g. used in

Bluetooth, has better spectral density

than 2-FSK modulation, i.e. more

bandwidth efficient

Digital Modulation

Phase Shift Keying (PSK):

Pros: Less susceptible to noise

Bandwidth efficient

Cons:

Require synchronization in frequency

and phase: complicates

receivers and transmitter Example: IEEE 802.15.4 / ZigBee


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Extending the Range of an RF System


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RF Parameters and RF MeasurementEquipment


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Part 2

RF Planning and Optimization


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Radio network optimization indicates the activities that you

collect and analyze the data of the running network or thenetwork to be put in to operation, and to check the causes

for affecting the network operation quality.

Radio network optimization pursues

Cost-effective use of network resources

Improves the quality of service (QoS) to an utmost

extent

Accumulates the basis and experience for the future

network expansion.

Radio Network Optimization


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Points to Note in RNO

Start Conditions of Network Optimization

Input and Output of Network Optimization

Process of Network Optimization

Process of Radio Network Optimization


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Start Conditions of Network Optimization

Radio network optimization can be started in

the following conditions:

After the network is put into operation or after the network is

expanded.- monitor the overall performance of the network

-Supplement and modify the aspects necessary to improve

network.

When the radio network quality is deteriorated.


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Input and Output of Network

Optimization

Before starting radio network optimization, make the

following documents ready:

Radio network planning report

Engineering parameter table Cell parameter table

Other information about the existing network (traffic

statistics, alarms, subscriberbcomplaints, andhistorical optimization records)


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Input and Output of Network

Optimization

After radio network optimization, write out the

following documents.

Radio network acceptance report

Radio network optimization report Engineering parameter table and engineering

parameter optimization record

Cell parameter table and cell parameteroptimization record


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The overall network optimization process

consists

Preparations for network optimization

Single site verification RF optimization

Service optimization

Network acceptance


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Process of Radio Network

Optimization

Network optimization is performed based on

A clear objective

In the guideline of specific process to collect

and analyze current network data

And to give corresponding optimizationsolutions.


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Optimization


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Optimization

The following data is collected as the basis for radio

network optimization

System parameters

Traffic statistics data Network simulation result

Alarms on the maintenance console

Subscriber complaint records

Signaling data

DT data


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What do we do?

Modify the parameters and use other physical

methods, to ensure that the network

performance and resources are optimized and

we provide appropriate suggestions for future

network maintenance and planning.


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What is our Focus?

We focus on these Key Performance Index (KPIs)

Accessibility

Retainability

Mobility

Traffic


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Credits

Texas Instruments


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Thank You !

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