Chapter 2 Radio Access Technologies

analog signaldigital signal modulatoinchannel codinginterleaving

Section 2.1Introduction

2-1

Section 2.2Analog and Digital Signal

(1/2) Digitalize 0 1 23

0000

0

0001

0010

0011

0100

0101

0110

0111

1000

1001

1010

1011

1100

1101

1110

1111

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

0000

0

0001

0010

0011

0100

0101

0110

0111

1000

1001

1010

1011

1100

1101

1110

1111

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

oe

1000 1010 K

He

(2/2) 0 1 0 1 samplingquantizationcoding

22

1 4 4 3

1 1 1 2

5 6 7 5

0

sX

00010100KK01010000

q

discrete signalsampling rate80008000Hz

Sampling TheoremNyquist Theorem 23003400HzPSTN8000

0 1 level4 bit16quantizationquantization error

coding 0 1 PSTNPulse Code ModulationPCM82568KHz64,00064,000bps

Section 2.3Radio Transmission and Modeling

reflection diffraction scattering

Propagation Loss

24

path lossslow fadingshadowingfast fading

25 multi-path fading

Propagation Model

Okumura-Hata Model urban

L c150MHz1500MHzhte35250hre110da

(1/2)

(2/2)

Section 2.4Modulation

26

modulation(1/3)carriermodulating signalmodulated signal

modulation(2/3)demodulation

modulation(3/3)analog modulation & demodulation digital modulation & demodulation

Amplitude ModulationAM Frequency ModulationFMPhase ModulationPM

27

H

lH

iH

eH

H

lH

iH

eH

(1/2) 0 1 pulsePulse Code ModulationPCM01

28

T i

T

Wv

iTBWvP

1

0

1

0

0

1

0

1

0

0

1

0

1

0

0

(2/2) bit error rate

linear modulationconstant envelope modulationcombined linear and constant envelop modulationspread spectrum modulation

0 1 Binary Phase Shift KeyingBPSKDifferential Phase Shift KeyingDPSKQuadriPhase Shift KeyingQPSK

BPSK01180

fccEbTb

29 DPSK

0 1

0

0

0

1

1

1

0

210 QPSK 4 2 000110 11

EbTbi 1 4 4

0 1 Binary Frequency Shift KeyingBFSKBFSKDiscontinuous Binary Frequency Shift KeyingD-BFSKBFSKContinuous Binary Frequency Shift KeyingC-BFSK

BFSK01

fcf EbTb

D-BFSKD-BFSK 0 1

BFSKC-BFSKC-BFSK

M-aryM-ary Phase Shift KeyingMPSKM-aryM-ary Quadrature Amplitude ModulationQAMM-aryM-ary Frequency Shift KeyingMFSK

211 MPSK2/M M=8

EMBED Equation.3

EMBED Equation.3

_1120983427.unknown

_1120984158.unknown

212 16-QAM

M-ary MFSK orthogonal

Section 2.5Spreading Spectrum

Frequency Hopping Spread SpectrumFHSSDirect Sequence Spread SpectrumDSSS

FHSS

213

6

5

4

3

2

1

1

2

DSSS1280101...0101chip01chip

214

lH

Spreading code

1

0

iW

1

1

-

1

1

-

1

iW

1

-

1

Spreading code

8

-

8

1

-

1

Nq[`

oe

1

-

1

WH

iWH

0

Section 2.6Channel Coding and Interleaving

channel codinginterleaving

error detectionerror correction block codingconvolution coding

GSM 260501327850 5313243787845620ms456bits/20 ms=22.8kbps

GSM GSM456857

Section 2.7Summary

Homework (1)- (8) 1, 3, 5, 7

After reading this chapter, the reader should be able to:Personal Communications ServicesPCSwireless communicationanytimeanywhereany terminalPCS networktelecommunication industrycomputer industry

Source coding , sampling, quantization, coding.Analog data: , ; discrete, . Audio analog data, , digital data , :0. Filter , .1. Sampling : . Ex: 4kHz , 8kHz ( 0.125 ms). samples, .2. Quantization : sampling , , . 6 bits , 0-63 , 29.2, 29 .3. Coding : ( code) binary pattern , 25 binary number 011001. 4. .Telephone voice is sampled: 8 bits, 8K times/secFor a HIFI orchestra recording, use more bits per sample, and more frequent samples.

sampling, (periodically) , . , sampling rate. Nyquist sampling theorem . 300-3800 Hz , 8kHz . () . 4kHz , 8kHz , , full voice (), , . sampling , ., ., input. 3 bits , (-4,4) ., zero , midrise (=0, 1 -1) . step size , uniform quantization. (), 1.3, 2 (=101) . 0.7 quantization noise granular error (). 5.3, 4 (=111) . 1.3 overload error (). sample bit , . quantization .Quantization noise : Quantization noise , . Ex: 1.8 error 0.2 3.8 .Quantization noise (or Signal-to-noise ratio) talker .

unique .fcGSMfc900MHzDPSK IS-95CDMA2000UMTSIS-951.2288MHz