¢ Continuity property ( see TV properties, properly
1 in
page59 )
Ee[ Etpldlsn, FD]{Eefeadcsisttdmaxllfolku ]
= E.dk ,54 tdmt Eellfflkr
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'° % Hmmmm
. !=*.us ,s ):here Ogn|µ is a look
of(determinist ' 4
choosea pjys st
.
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Gelfand - Pinker ( 1980)Tuesday
m-tffyapyf.sn#nkdei-
f S" iid B
This is the moot general bk you may
replace Pylx ,s← Py
,s1×,sthis
gives
t.es#*EFtfEatmD*tarinxfgsEfFBttEpIBnp;xIixin
m-tffxifphgnyn.gl#kDF-m.xICxiHs)
It Pxls
S" iid B
m_yfzxnfch.me#dji~PWps → the answer is not the same as above !www.gniidPSExample 1 : Write twice to optical disc
.
in send time you use you can change
the Os to 1 's but not ow.
around
in here encoder gets non . causal info (you can read the whole disk) but decoder has no info .
Example 2 : Gaussian channel w/ known noise (eg . stray interference)
→ EX 1 and 2 are equiv . in [f_p and I Versions.
That :
c= max Ilu ;y ) - I( uis )Puns
Again uses synthetic channel at encoder
↳block dig.
of Thm : (Not the problem )
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µrministic actually
,
doesn'tMhaapfaty
n→HoIIuI÷thExfEt"sn~Ps
Let's see Thm in action first
In Example 1 : Channel : Y=XvS s~Ber(p)
Let U=×={ 1 if st
2- if so where
[email protected] )Pu=Hs=o=Y2 =Uvs
Therefore,
Y=U ( see' KUVS when so # st
,at aid
' H 4
Il Yiukhlu )
I ( y ;u ) - I( U;sl= Hall - Ilu ;s )
=H( uls )
=lP[ so ] .= I→ This actolly maximises ICUIY ) - Il Uis )
, just consider that
decoder also has 59,
then it is tp becauseyou can ignore ended part
Example 2 :
"
Writing on Dirty Paper"
( cost ) :(channel : Y - XTSTN,
SIN )both Gaussian
Choose U,
X,
S to be Jointly Gaussian. and XIS and HIUIX ,s)=O
Optimize Ui WLOG U=s+XX+No¥%
c=tlgkPN#
noneiowwithout state
Nforhen)
Gelled I Pink
G- P Achievability proof
Start by choosingFux
,sst
. RLIPTU ; Y) - Iplu ; s )
LetF-Bxuy-BFuxsYPyisxFgnxnunyn-lTFsxuyEn@TransmitmessgeandpaddigmatrofRmgotroleRglMessagelpaddiypchoosecarefHguoepbo.d
digto make transmission
undated with state
choose Rgt ( Ilu ,s ),
Iluiy - R )
RTRG( IHIY ) ( so that we can decode it by channel ady)
-
total rate
Random Codebook ~PI : E{ unlm.my) }
ProofusingJointtypicolilyenadefwearesuppressiyXintkegljne.mbd.wEncoderipun1p@GimnmandSYfindmgs.t
. @" (m.my , g) e Jdn'
bwrt F
Decode: Find unique m sit .
Fmgsit
.( Mm
, mgl,
Y" ) € To
"
whey,
.
→E=ranalysis :
EdigerSmall because Rg
> Iluis )
g) IY"
small era because Rtihg( IIU
:
[email protected])Punlmsn
a- look -
up
Un =un( m.mg)
e-
Induced distribution
[email protected];Idaho
,
deaden(Payne"°%areµ, .go.m.oh.ge that part)f¥tainmLet
Qsnmgµ=m=Qmg*%mmg
unit. induced ↳look
up a" (Ming)
of M
pjnµ(snlunlmmgl)
Efllpsnmghnmtssnaylmnttr ]→0 htanase
as Icu ;D
( soft
coveyKuen
.)now Ute property of TV same channel
different input
output of channel is
4o⇐