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HƯỚNG ĐẾN MÔ HÌNH TOÁN HỌC
ĐÁNH GIÁ HIỆU NĂNG CỦA KỸ THUẬT
MÃ HÓA STTC
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CHƯƠNG 1
KỸ THUẬT MÃ HÓA KHÔNG GIAN-THỜI GIAN LƯỚI STTC
1.1 Phương pháp mã hóa không gian - thời gian
1.1.1 Giới thiệu
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1.1.2 Các hệ thống mã hóa không gian thời gian
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1.3 Nguyên lý giải mã mã lưới
1.3.1 Giải mã sử dụng giản đồ lưới
ILh?BKB?SJ"*($a(@"l&&$Cxm($'C11 01 01 00 10 11 QA(!$#
!>(Ut=0 *t=6 eILhQs(!$FH$]sAS
0
=00f2$@TX*@^CXAJ11
$RKB!I?SL€!I?SX&$AQ>output = 18L_@E&$CGt(L>(!Qs(!$F1
:
s
t=1. 1>C@T8X*input = 01$RKB!I?SL€~CG[@4($&$Aoutput = 18&O($"
XaG@$[!I(@EJ"*$R&$CxK($a(@"l&L€J1 1 0 1 0 0
R($:2-$[!I(@EJ"*$R&$CxK($a(@"l&J::,:,,
1.3.2 Khoảng cách Hamming trong giải mã lưới
$">@SK[8H$AI(!&F&$>??(!hJLcHg%H$F&($>C!•>9Lc($4
+$v(2“MXm/ZQY(8!ILh=IGQ>JxK@_(@cX*iK@^CY(8&$CxK($a(
@"l&J1111e$>GXR1101f2
UL_@E/"*8>$NG&T9&F&$@U1
,
8?B&$Ainput = 11 (h=0)X?B&$A
input = 00 (h=2).
R($:2o$AI(!&F&$>??(!$&D>9($F($Qs1
,

ˆQ(!QŽ(!8>L€&$y(@"#(!+$m>/"*8@"#(!?&TH$AI(!&F&$>??(!
$($|$_(2
 [+$dA8st=18@^CXA&T:KmJx8X&I$>@"#(!@Q#U1
:
@C&T
H$AI(!&F&$>??(!!c(!($>C h=12.A@T8KB!I?SL€=d?=M&I$>
@"#(!(GQA(!&F&K"*&[+$dA2
st=2, input=018$R@"#(!@U1
;
L€&Th=0. ’(@"#(!@U1
9
L€&Th=1
e&T$>@"#(!f2.AH$AI(!&F&$>??(!@SH$F&($>C(Y(>&T$t&$y(@"#(!
/"*@t=F&@4($/•J'CQ>2
R($:2:,$AI(!&F&$>??(!QA(!U(!@As(2
CG($Y(8@t(v(!&>A@B(&aG&$A$CaAF(8QA(!$%&[8>L€m($‰(!
H$AI(!&F&$>??(!QY((@As(?(T@~C>
H = h
0
+ h
1
+ … + h
n
R($:2::‰(!H$AI(!&F&$>??(!
UL_@EQY(8>$NGH$AI(!&F&$>??(!L€@"l&m&$J‘G~C>U(!@As(8
XL>CH$~C>?BLc@_(X4$#!>((A@TeQA(!Q"#(!$l+(GJt=5f$RKB
!I?SL€~CG[@4($&$y(@"#(!?&T‰(!H$AI(!&F&$>??(!J($|($N2
$dAL_@EQY($R@"#(!&TH=1

J@"#(!@c($N8/A@T8/•J'C@^CQ>L€J

110102
1.3.3 Giải mã sử dụng thuật toán Viterbi
m/ZQY($t$'(V@"#(!@QA(!L_@EJ"*8L>C@T/%>QY(‰(!H$AI(!
&F&$>??(!?*~CG[@4($&$y(@"#(!&THJ($|($N2
CG($Y(8@cX*&F&KB?SJ"*J*($_(8($"QA(!?s(!/@B(!8@B/
!*$s(k&T$tJY(*j$AP&o$RLc@"#(!&^(=M&T$tJY(*;9$AP&9Vj
@"#(!2
$CaAF(dQKe@"l&+$FQt(XA({?:ojrf&$A+$M+JAsQUQN($C
@"#(!QA(!‰(!Lc&F&@"#(!2
$CaAF(&$‚Q>QŽ(!8([C&T9@"#(!@"l&!>A($>C$($:Qs(!$F$R>
&$‚&^(~C>(v?*@"#(!&TH$AI(!&F&$>??(!($|$_(2T&F&$H$F&8
([CHJ@B/!*$s($R>&$‚&^(~C>(v?*2
k-1
@"#(!$>GXR 2
k
@"#(!8X
@B/@"#(!@e$dA@_(X4$#!>(f!N+i$AP&VJ^(@B/!*$s(H$R&T
$t($a(@"l&$<(!(&$m($=F&QA(!$^C$[&F&Q"#(!$l+2
1_@E/"*$t$'(&F&$?KB?S$T>=F&@4($@"#(!@c($N(!>G&IH$
&TJx=IGQ>2
s t=0 8K\@^CUQs(!$F1
,
8&T9@"#(!@[+J@*1
,
X* h=2$AP&
@*1
:
X* h=02
st=18&TJxK@_(=IGQ>X&TN&Ii@"#(!@U$>Qs(!$F1
,

X1
:
8
/A&TJx=IGQ>(Y(H$<(!&T@"#(!(A&T‰(!>??(!H=02
R($:2:9$CaAF(dQKQA(!!I?SJ"*
st=38/As?xQs(!$F&T9@"#(!(Y(L€&T-@"#(!&^(+$I=MX*
&F&‰(!H$AI(!&F&$>??(!H$F&($>C2
R($:2:;T-@"#(!@*$#@t?…;
$dAdQK8&F&@"#(!&TJ*($_(L€H$<(!$tJ@"#(!&$m($=F&(Y(KB
!I?SL€JAsK|&F&@"#(!(G@t=hJm@"l&($>($$_(2QA(!Q"#(!$l+(G8
>L€JAsK|i@"#(!&TJ*(($N2
R($:2:iJAsK|&F&@"#(!&TJ*(
st=48!ILh&T[+JxK@_(=IGQ>8&‘(!L€&T-@"#(!@*Qs(!$F
t=4($"(!KB?S$T>L€K|@i@"#(!&T&>A($N2
R($:2:V)x$O9=IGQ>QA(!~CFQR($QCG(
st=58[+Z&&T-@"#(!@"l&sAQ>8KB!I?SL€X0(&$‚=Mi@"#(!&T
J($|($N2CG($Y(8]@vG=IGQ>Q"#(!$l+J&Ti@"#(!&T&3(!‰(!
H$AI(!&F&$>??(!8XRH$<(!&T&F&$(A@tJ%>&$y((Y(KB!I?SL€J%>
&$y((!0C($Y(9QA(!i@"#(!(G@t@">XA($T?i@"#(!&T‰(!H$AI(!
&F&$>??(!($|($N2
R($:2:j$y((!0C($Y(9QA(!Lci@"#(!&T&3(!‰(!H$AI(!&F&$
>??(!
st=68&$6(!>&T$t&$y(@"l&@"#(!@&TJ?(8U@TLCGQ>@"l&/•
J'C!c&2[$6&~CFQR($!I?S2
R($:2:r$y(@"l&@"#(!&T
?(
UX'&=F&@4($@"l&H
min8
@(!"l&Q]Js8>@"l&@"#(!($"L>C
S

0
<= S
1
<= S
2
<= S
3
<= S
4
<= S
5
<= S
6
*~C"*&(M@O&$AK:8&’((MJ(&$AK,8/•J'C!c&($a(@"l&L€J
1-1-0-1-0-02
QY(@vGJA(KB~CFQR($!I?S&D>?SJ"*Lh/Z(!$CaAF(dQK8
X*!I$[J&T9JxQY(@"#(!QCG(8KB!I?SL€&$y(@"l&@"#(!@c
($N/%>QY(‰(!H$AI(!&F&$>??(!8U@TLCG(!"l&Q>/•J'C!c&2”&F&
$#@t?[+$dA8~CFQR($!I?S&‘(!=IGQ>"_(!%2
1.3.5 Bộ mã hóa STTC
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