蜂窝小区同频干扰的Matlab仿真Word下载.docx

蜂窝小区同频干扰的Matlab仿真Word下载.docx

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ischaracterizedbytheinterferenceataspecificposition,e.g.atthefringeofacelloratthecenterofacell.Becauseoftherandompositionofamobilesubscriber（MS）andotherrandomfactors,theco-channelinterferenceisalsoarandomvariable.Asknown,interferencecancelationtechniquecangreatlyimprovethesystemcapacityinthecellularmobilesystem,especiallyintheCDMAsystems.Itishelpfultoknowthedistributionoftheinterferencewhenadoptinginterferencecancelationtechniques.Therefore,ourexperimentdevotestofindthedistributionoftheco-channelinterferenceinthecellularmobilesystemwithclustersize

N.LetusassumethecellradiusR,eachMScouldappearatanypositioninthecellwithequalprobability.TheaveragereceivedpowerPratadistancedfromtransmitteris

𝑝

=𝑝

（𝑑

）-𝑛

approximatedas𝑟

0𝑑

,whereP0isthepowerreceivedatasmalldistanced0from

thetransmitterandnisthepathlossexponent.Theexperimentrequirementsarethefollows.

DESCRIPTIONOFTHEEXPERIMENTS

1.Writeaprogramtocalculatethesignalinterferenceratio（SIR）intheforwardlink,andrepeatsitbyrandomlychangingthepositionoftheMS.Afteranumberofsimulations,usethesimulatedresultstodrawthehistogramoftheSIR（S=I）.TrytoobtainhistogramswithdifferentpathlossexponentnandclustersizeN.Concludeyourresults.

Theco-channelinterferenceintheforwardlinkcanbecharacterizedinfigure1.AMSwillbeinterferedbytheco-channelbasestation.Inoursimulation,weconsiderthe18co-channelcell,including6cellsinthefirstloopand12cellsinthesecond,nomatterwhattheclustersizeNis.

Figure1forwardlinkco-channelinterference

（1）Firstly,weshouldrandomlychoosethepositionoftheMSinthecell.Sincethecellishexagonwhichishardtohandlewecutandpasteitintoasquare.Aswecanseeinfigure2,thecenterofthecoordinationisthecenterofthecell.ThesquarewechooseisABCD.WethenrandomlychooseapairofxandyasthecoordinateofMS.IfMSlocatesintriangle1wecutandpasteittotriangle3andifitlocatesintriangle2wemoveittotriangle4.

Weassumetherangeofthebasestationis0.1asradiusofclusteris1.FortheMSwholocatedwithinthisarea,wechangeitsdistancetobe0.1asitistooclosetothebasestaion.

Figure2randomlychoosethepositionofMSinacell

Matlabcode:

RandPOS.m

%*******************************************************************

%ThisfunctionistogettherandomlylactionoftheMSwithmtimes.

%zisam*1matrixwithcoodinatevaluex,y

%*******************************************************************function[z]=RandPOS（m）

%********getrandomvalueofx,ywithinasquare*****%x=1.5*rand（m,1）-1;

y=sqrt（3）*rand（m,1）-0.5*sqrt（3）;

%********useforlooptocutthesquareintoahexagon*****%fork=1:

m

ifx（k）>

-1&

&

x（k）<

-0.5&

y（k）>

（1+x（k））*sqrt（3）x（k）=x（k）+1.5;

y（k）=y（k）-sqrt（3）/2;

elseifx（k）>

y（k）<

-（1+x（k））*sqrt（3）x（k）=x（k）+1.5;

y（k）=y（k）+sqrt（3）/2;

end

%********iftheMSistoonearlytothebasestation ******%ifsqrt（x（k）^2+y（k）^2）<

0.1

x（k）=0.1;

y（k）=0;

z=x+j*y;

.

（2）Secondly,weshouldcalculatethecoordinateofco-channelbasestation.AsweknowtheclustersizeNwecancalculatethe（i,j）pairbytheformula𝑁

=𝑖

2+𝑖

*𝑗

+𝑗

2

ClusterN.m

%*********************************************************

%Thisfunctionistofindi&

jcorrespondtoagivenN

%asN=i^2+j^2+ij

%iiandjjistheresultofi,j

%********************************************************function[ii,jj]=ClusterN（N）

%thelargestnumberofiandjissqrt（N）

fora=0:

sqrt（N）

forb=0:

ifa^2+b^2+a*b==Nii=a;

jj=b;

end;

%endifend;

%forjj

（3）TakingN=7asexample,wecancalculatethecoordinatebyreferringtofigure3.AccordingtothevalueofIjpairandanglesinthefigurewecangetthecoordinateofthefirst loop by the formula:

𝑗

×

𝑝

𝑖

+𝑗

𝑝

𝑗

𝑙

𝑜

𝑐

𝑎

𝑡

𝑛

（𝑘

）=3×

（𝑖

𝑒

6

3×

（𝑘

‒1）