Module 3 Radio mobile propagation system

7/24/2019 Module 3 Radio mobile propagation system

1/96

Module 3Radio Propagation in Mobile

System

Presented By

Megha Das K


2/96

Summary

Antenna basics Cellular & PCS Antennas

MIMO

Mobile Radio Propagation

1. Free space Propagation Model

2. Two Ra Model

!. Outdoor Indoor Propagation Model

". Fading C#annels

". Raleig# & Ricean $istribution


3/96

Antenna basics

An antenna is a device used to transform an RF signal, traveling on

a conductor, into an electromagnetic wave in free space.

The antenna is the interface between the transmission line and

space

Antennas are passive devices; the power radiated cannot be greater

than the power entering from the transmitter


4/96

Antenna basics

When speaking ofgainin an antenna, gain refers to the idea thatcertain directions are radiated better than others

Antennas are reciprocal - the same design works for receiving

sstems as for transmitting sstems

Simple Antennas ! The "sotropic Radiator would radiate all the

power delivered to it and e#uall in all directions.The isotropic

radiator would also be apoint source


5/96

Antenna basics

Major Difference Between Antennas And Transmission Lines

transmission lineuses conductor to carr voltage $ current

radio signaltravels through air %insulator&

antennasare transducers

- convert voltage$currentinto electric$ magnetic field

- bridges transmission line $ air

- similar to speaker'microphone with acoustic energ


6/96

Antenna basicsTypes of antennas

simple antennas! dipole, long wire

comple( antennas! additional components to

shape radiated field

provide high gain for long distances or weak signal reception

si)e fre#uenc of operation

combinations of identical antennasphased arras electricall shape and steer antenna

Transmit antenna! radiate ma(imum energ into surroundings

Receive antenna! capture ma(imum energ from surrounding radiating transmission line is technicall an antenna good transmission line * poor antenna


7/96

Antenna basics

Transmit & Receive antennastheoreticallyare the same %e.g. radiation fields, antenna gain&

practicalimplementation issue!

transmit antenna handles high powersignal %W-MW&

- large conductors $ high power connectors,

receive antenna handleslow powersignal %mW-uW&

Antenna Performancedepends heavil on

+hannel +haracteristics! obstacles, distances temperature,

ignal Fre#uenc

Antenna imensions


8/96

Antenna basics

Propagation Modes five types

!"# $ro%nd or S%rface wave!follow earths contour affected b natural and man-made terrain salt water forms low loss path several hundred mile range -/ 01) signal


9/96

Antenna basics

!# Space 'ave 2ine of ight %23& wave 4round iffraction allows for greater distance Appro(imate 0a(imum istance,Din miles is

%antenna height in ft&

5o trict ignal Fre#uenc 2imitations

rxtx hh +D*

hrxhtx


10/96

Antenna basics

!(# S)y 'aves

ionosphere

transmittedwave

reflected

wave

refractedwave

skip distance

reflected off ionosphere%6-76 miles high& large ranges possible with single hop or multi-hop transmit angle affects distance, coverage, refracted energ


11/96

Antenna basics

(4) Satellite Waves$esigned to pass t#roug# ionosp#ere into space

uplin% ground to space'

down lin% space to ground'

Fre(uencies )) critical *re(uenc

penetrates ionosp#ere wit#out re*lection

+eosnc#ronous orbit 2!% ,iles snc#roni-ed wit# eart#sorbit'

long distancesresult in #ig# pat# loss

/M energ disperses o0er distances

intensel *ocused bea, i,pro0es e**icienc


12/96

Antenna basics

!*# radar+

re#uires high gain antenna

sensitive low noise receiver

re#uires reflected signal from ob8ect 9 distances are doubled

onl small fraction of transmitted signal reflects back


13/96

Antenna basics

Dipole Antennas!,ert-#+ simple, old, widel used

- root of man advance antennas

consists of spread conductors of wire transmission lines each conductor is : in length total span * < small center gap

gap

: :

Transmission

2ine

Antenna Types


14/96

Antenna basics

M%lti.Band Dipole Antennas

Transmission2ine

='>+

2

+

2

='>

'>'>

use = antennasupport several widel separated fre#uenc bands

e.g.HAM Radio - 3!"MH#-$%MH#

Traps+&,' elements inserted into dipole arms

arms appear to have different lengths at different fre#uencies traps must be suitable for outdoor use ndraffects of trap impact effective dipole arm length-ad8ustable not useful over /601)


15/96

Antenna basics

/lementary Antennas low cost 9 fle(ible solutions

Long 'ire Antenna effective wideband antenna

length l * several wavelengths

- used for signals with 6.=l? ? 6.7l

- fre#uenc span * 7!=

drawback for band limited sstems - unavoidable interference

near end driven b ungrounded transmitter output

far end terminated b resistor

- tpicall several hundred $ impedance matched to antenna @

transmitter electrical circuit ground connected to earth


16/96

Antenna basics

0olded Dipole Antenna- basic dipole folded to form complete circuit

- core to man advanced antennas

- mechanicall more rugged than dipole

- =6 more bandwidth than dipole

- input impedance B

- close match to std /66twin lead wire transmission line

- use of different diameter upper $ lower arms

allowsvariable impedance

'


17/96

Antenna basics

Loop & Patch Antenna9 wire bent into loops

Patch Antenna! rectangular conducting area with CC ground plane

Area A

5-turns

(* ma(imum voltage induced in receiver b D0 field

E* magnetic field strength flu( of D0 field

A* area of loop

5* number of turns

f* signal fre#uenc

k* phsical proportionalit factor

(* k%f&)A5Antenna

lane


18/96

Antenna basicsAntenna Types


19/96

Antenna basics

**1"2 dBDipole

(344 dB

5sotropic

Beamwidth

.( dB

$ain !over

isotropic#

Shape6ame Radiation Pattern

4

(4

*4

44

*

"217 dB

"41" dB

.4183 dB

(1"2 dB

71"2 dB

Para9olic

Dipole

,elical

T%rnstile

0%ll 'ave

Loop

:agi

Biconical

,orn

"*"* dB,orn

(34;44"2 dB


20/96

Cellular &

PCS Antennas

Analog cellular on the G76 01) band ince =BHB %e(perimental&, =BG= commercial; analog F0 now mostl phased

out

igital +ellular'+ on G76 and =B66 01) bands

ince I=BB= with immense growth rate stems on the =.B 41) %=B66 01)& band

Jsuall called ersonal +ommunications stems even when technologicall identical to G76 01) sstems %such as "-B7 +0A

or "-=/K T0A&

B66 01) and =.G 41) bands used in Durope and other continents,mainl for 40 %4lobal stem for 0obile communication&


21/96

Cellular & PCS Antennas

Technicall, a cellular sstem has properties! +ellular fre#uenc re-use

1andover %also called handoff&

o do most personal communications sstems %+s& onl e(ception is +T- public cordless %current implementations& without handover

Toda the 5orth American business distinction is sometimesbased on fre#uenc band... G76'B66 01) is described as cellular

including digital cellular such as 40, "-7>, "-=/K

=.B 41) is described as*'+


22/96


0anual operator-handled mobile radio %=B>7L&

Automatic 0obile Radio, e.g. ecode, "0T %=BK6L&

Trunked radio %=BK6L& cellular-like fre#uenc re-use

but no handoverM

+ellular radio %=BHGL& re#uired new technolog! control of mobile radio operation via messages from base

0obile transmit %T(& fre#uenc and power

+an be changed duringa conversation to select best base station orcompensate for distance

Handovercontinues conversation as mobile station moves from cell tocell


23/96

Cellular & PCS AntennasCellular Frequency Re-use

+ertain tpes of radio modulation e(hibit the Ncapture effectO

When ratio of desired signal power to undesired %interference $noise& power is greater than the Ncapture ratio,O onl the strongerdesired signal is apparent in the output

+apture phenomenon works for +ertain tpes of modulation! F0, hase 0odulation -- but.A0

Eandwidth of signal is tpicall large compared to data rate for auseful capture ratio!

Analog cellular /6 k1)! c.r. is K/'= or =G dE

5arrow band 5A0 =6 k1)! c.r. is 66'= or / dE


24/96

Cellular & PCS AntennasCellular Frequency Plan

Fre#uenc plan depends on capture ratio resulting from RF technolog

Radio signal strength, path loss or distance-related attenuation

Appro(imatel! received power *='distance>in cit /mpirical approximation< not 9ased on theory

D(ponent in range %open space& to > %cluttered urban

environment&


25/96

A fre#uenc plan is characteri)ed b a cell cluster count in

which each fre#uenc is used in one cell

2ow capture ratio, high path loss re#uires small cell cluster %/

or >&

1igh capture ratio, low path loss re#uires large cluster %H or =

or more&

Cellular & PCS AntennasCellular Frequency Plan


26/96


Frequency Clusters


27/96

Cellular & PCS AntennasCell Splitting

"ncrease of capacit b H in center cell %for n*H plan&

Eut there is a lower limit on cell si)e %due to appro(. min. 7 mWhandset T( power& so ou canPt split again and again withoutlimitation

+ell splitting is the most costl choice, used onl after first usingmethods which add capacit to an e(isting cell site


28/96

Cellular & PCS AntennasGeneral PCS System Structure

O**icial bloc% diagra, *ro, +SM' s#owing ,a3or de*ined inter*aces4.

0

0+

E+ ET

E+ ET

E+

ET

ET

A

A-bis

Jm

12R Q2R

Au+

D"R

30+

to T5

to other 0+s

Q2R

4

E

D

+

F

econd Q2R is optional

E


29/96

VR !ata "ase

0isleading name- NQisitedO 2ocation Register

ata needed to communicate with a 0 D#uipment identit and authentication-related data

2ast known 2ocation Area %2A& group of cellsS

ower +lass, other phsical attributes of 0

2ist of special services available to this subscriber e.g. circuit-switched FA, etc.S

0ore data entered while engaged in a +all +urrent cell

Dncrption kes

etc.



30/96

#R !ata "ase

1ome 2ocation Register 5eed not be part of the 0+

3ne 12R can be shared b several 0+s ome operators plan a single regional 12R for shared use b several 0+s

+ontains NeverthingO permanent about the customer

"0", "0D", irector 5umber, classes of service, etc. +urrent cit and 2A

particularl when not in home sstem %when NroamingO&

Authentication related information

"n some implementations 12R and Q2R are thesamephsical

data base Q2R records distinguished logicall via Nactive in Q2RO bits



31/96

"ase Station Assembly

Antennas Transmit +ombiner rocessing

Receive 0ulti-coupler'2ow 5oise istribution Amplifier

Ease Transceiver

Transmitter ection Receiver ection

Antenna iversit rocessing in Receiver

Ease tation +ontroller

upport e#uipment! power, air conditioning,



32/96

"ase Station $quipment

5ot shown! band pass or band re8ect filters in antenna lines, power e#uipment, air-

conditioning, test transceiver, alarm e#uipment, etc.

T(

ant.

E+

ET

A-bis

ET6

ET=

ETn

111

A

first

R(

ant.second

R(

ant.

T(

+ombiner

R(

multi-

coupler

R(

multi-

coupler

E+F

ETwo standardi-ed interfaces !A and A9is in $SM# permit competitive s%ppliers for 9ase e=%ipment



33/96

%nside te "o'es

Transmit +ombiner contains Tunable resonant cavit filters irectional couplers

"ts purpose! feed mostT( power to T( antenna, notto other

transmitters %where the signal power does no good and maeven cause overheating or damage&

Receive multi-coupler is RF low-noise pre-amplifier similar to TQ communit antenna distribution sstem

distributes R( signal to all receivers at same level the would get froman unshared R( antenna


C ll l & PCS A t


34/96

(y ) "ase R' Antennas*

ual antennas diversit improves base reception sensitivit b asmuch as to 7 dE vis-U-vis a single antenna

pacing of antennas should be oddmultiple of l'>, preferabl

VGl apart

everal methods for diversit combining! witching'selection

D#ual gain

0a(imal ratio

vendor design choice, not standardi)ed



35/96

(y +#F "ands*

NEecause the are availableO is a legal'historical reason onl,although ver significant... Q1F and below, absolutel no available bandsM

Former point-point microwave and militar bands were made available around 41)band

till some incumbent microwave sstems

4overnment auctioned bands to highest bidder in =BB6s trong financial motive to move #uickl

Technological reasons! J1F follows Nline of sightO propagation

2ittle'no over-hori)on or NskipO radio propagation

0F, 1F short-wave bands would be impractical for cellular 1F bands re#uire much more costl components, and some bands are used for

e(tensive installed microwave or have strong atmospheric attenuation




36/96

,ort American ./ M#0 "and Cellular

Spectrum

3riginal /6 k1) carriers =-KKK assigned =BG= Additional carriers assigned =BGH 5o more carriers likel until after ear 666 3perator optional additional "-=/K setup carriers in middle of AP and EP sub-

bands. 3rdinaril used for voice "-=/K allows an fre#uenc to be used for T0A setup carrier "-B7 uses =6 NchunksO each =.7 01) bandwidth

Paired Bands

ownlink- Forward ub-bandJplink-Reverse sub-band 0R band

G>

01)

G>B

01)

GKB

01)GB>

01)

G7

01)

G/7

01)G>7

01)

G>K.7

01)

GB6

01)GB=.7

01)

GG6

01)

GH6

01)

A>> A A> B>B

".(((??".

"4(

337.

7"3

7"7.

7??((2.333

A>> A A> B>B

".(((??".

"4(

337.

7"3

7"7.

7??((2.333

Set%p.control carriers !" each operator#

Speciali-ed

Mo9ile Radio

%se



37/96

,ort American 12// M#0 "and PCS Spectrum

i Elocks A $ E are for use in 0etropolitan Trading Areas %0TAs&

i Elocks +, , D $ F for use in Easic Trading Areas %ETAs& suburban or ruralS

i "n an service area, >6 01) block combinations are permitted

i +ellular operators are eligible for onl one =6 01) block in their e(isting

services areas

0@@ P@S Spectr%m Allocation . %ne ?< "??2

=GG7

01)

ata Qoice

Paired Bands

2icensed ownlink2icensed Jplink Jnlicensed

0TAE

T

A0TA

E

T

A

E

T

AETA

A E D F +

0TAE

T

A0TA

E

T

A

E

T

AETA

A E D F +

=G76

01)

=B=6

01)

=B/6

01)

=BB6

01)

=GK7

01)

=GH6

01)

=GB6

01)

=GB7

01)

=B6

01)=BK7

01)

=BH6

01)

=BH7

01)

=B76

01)=B>7

01)



38/96

M%M

"n radio, m%ltiple.inp%t and m%ltiple.o%tp%t,or M5M%pronounced as Xm-mohX or Xme-mohX&, is a method for

multipling the capacit of a radio link using multiple transmit and

receive antennas to e(ploit multipath propagation

0"03 has become an essential element of wireless communication

standards including Wi-Fi,/4$>4.

0ore recentl, 0"03 has been applied to power-linecommunication for /-wire installations as part of "TJ 4.hn standard

and 1omelug AQ specification.

M%M


39/96

Aspirations 4Matematical5 o6 a System

!esigner

5ig# data rate

Yualit

Achieve

N+hannel +apacit %+&O

0inimi)e robabilit of Drror %e&

Real-life "ssues

0inimi)e comple(it'cost of

implementation of proposed

stem

0inimi)e transmission power

re#uired %translates into 5R&

0inimi)e Eandwidth %fre#uenc

spectrum& Jsed

M%M

M%M


40/96

Antenna Con6igurations

Single6Input6Single6Output SISO' antenna sste,

Theoreticall, the =4bps barrier can be achieved using this configuration

if ou are allowed to use much power and as much EW as ou so pleaseM

D(tensive research has been done on "3 under power and EW

constraints. A combination a smart modulation, coding and multiple(ingtechni#ues have ielded good results but far from the =4bps barrier

channel

Cser data stream

Cser data stream

M%M

M%M


41/96

M%M Antenna Con6iguration

Cser data streamCser data stream

1

1

"

MT

1

1

1

"

MR

1

1

1

1

1

channel

7se ,ultiple trans,it and ,ultiple recei0e antennas *or a

single user

5ow this sstem promises enormous data ratesM

M%M

M%M


42/96

!ata +nits

Will use the following terms loosel and interchangeabl,

Eits %lowest level&!


43/96

Sannon7s Capacity 4C5

4iven a unit of EW %1)&, the ma( error-free transmission rate is+ * log%=


44/96

Spectral $66iciency

pectral efficiencies of some widel used modulation schemes

The Whole point! 4iven an acceptable e , realistic power and EWlimits, 0"03 stems using smart modulation schemes provide

much higher spectral efficiencies than traditional "3

Sc#e,e b8s85-

9PS: 1

;PS: 2

1


45/96

M%M System Model

Cser data stream

1

1

Cser data stream

1

1

1

1@hannel

Matri; ,

s=

s

s0

s

=

0

yTransmitted

vector

Received

vector

1

1

h=

= h=

M%M

M%M


46/96

M%M System Model

y* ,s< n

Where ,*

h== h= LL.. h0=

h= h LL.. h0

h=0 h0 LL.. h00. . LL.. .

0T

0R

hij is a @omple; $a%ssian random varia9le

that models fading gain 9etween the ith

transmit and jth receive antenna

M%M

M%M


47/96

Capacity o6 M%M Cannelsy ,s E n

Let the transmitted vector s 9e a random vector to 9e very general and n is normali-ed noise1 Let the totaltransmitted power availa9le per sym9ol period 9e P1 Then

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Module 3 Radio mobile propagation system