function?vHat?=?decodeLogDomain（rx?H?N0?iteration）
%?Log-domain?sum?product?algorithm?LDPC?decoder
%
%??rx????????:?Received?signal?vector?（column?vector）
%??H?????????:?LDPC?matrix
%??N0????????:?Noise?variance
%??iteration?:?Number?of?iteration
%
%??vHat??????:?Decoded?vector?（0/1）?
%
%
%?Copyright?Bagawan?S.?Nugroho?2007?
%?http://bsnugroho.googlepages.com

[M?N]?=?size（H）;

%?Prior?log-likelihood.?Minus?sign?is?used?for?0/1?to?-1/1?mapping
Lci?=?（-4*rx./N0）‘;

%?Initialization
Lrji?=?zeros（M?N）;
Pibetaij?=?zeros（M?N）;

%?Asscociate?the?L（ci）?matrix?with?non-zero?elements?of?H
Lqij?=?H.*repmat（Lci?M?1）;
?
%?Get?non-zero?elements
[r?c]?=?find（H）;

%?Iteration
for?n?=?1:iteration
???
???fprintf（‘Iteration?:?%d\n‘?n）;
???
???%?Get?the?sign?and?magnitude?of?L（qij）???
???alphaij?=?sign（Lqij）;???
???betaij?=?abs（Lqij）;

???for?l?=?1:length（r）
??????Pibetaij（r（l）?c（l））?=?log（（exp（betaij（r（l）?c（l）））?+?1）/...
?????????????????????????????（exp（betaij（r（l）?c（l）））?-?1））;
???end
???
???%?-----?Horizontal?step?-----
???for?i?=?1:M
??????
??????%?Find?non-zeros?in?the?column
??????c1?=?find（H（i?:））;
??????
??????%?Get?the?summation?of?Pi（betaij））????????
??????for?k?=?1:length（c1）

?????????sumOfPibetaij?=?0;
?????????prodOfalphaij?=?1;
?????????
?????????%?Summation?of?Pi（betaij）\c1（k）
?????????sumOfPibetaij?=?sum（Pibetaij（i?c1））?-?Pibetaij（i?c1（k））;
?????????
?????????%?Avoid?division?by?zero/very?small?number?get?Pi（sum（Pi（betaij）））
?????????if?sumOfPibetaij?????????????sumOfPibetaij?=?1e-10;
?????????end?????????
?????????PiSumOfPibetaij?=?log（（exp（sumOfPibetaij）?+?1）/（exp（sumOfPibetaij）?-?1））;
??????
?????????%?Multiplication?of?alphaij\c1（k）?（use?‘*‘?since?alphaij?are?-1/1s）
?????????prodOfalphaij?=?prod（alphaij（i?c1））*alphaij（i?c1（k））;
?????????
?????????%?Update?L（rji）
?????????Lrji（i?c1（k））?=?prodOfalphaij*PiSumOfPibetaij;
?????????
??????end?%?for?k
??????
???end?%?for?i

???%?------?Vertical?step?------
???for?j?=?1:N

??????%?Find?non-zero?in?the?row
??????r1?=?find（H（:?j））;
??????
??????for?k?=?1:length（r1）????????
????????
?????????%?Update?L（qij）?by?summation?of?L（rij）\r1（k）
?????????Lqij（r1（k）?j）?=?Lci（j）?+?sum（Lrji（r1?j））?-?Lrji（r1（k）?j）;
??????
??????end?%?for?k
??????
??????%?Get?L（Qi）
??????LQi?=?Lci（j）?+?sum（Lrji（r1?j））;
??????
??????%?Decode?L（Qi）
??????if?LQi??????????vHat（j）?=?1;
??????else
?????????vHat（j）?=?0;
??????end
???????????????????????
???end?%?for?j
???
end?%?for?n

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????2568??2007-05-04?15:09??01吞吐量—不同碼長-可變碼率LDPC\decodeLogDomain.m

?????文件???????2096??2008-12-10?10:15??01吞吐量—不同碼長-可變碼率LDPC\decodeLogDomainSimple.m

?????文件???????6550??2008-07-23?10:08??01吞吐量—不同碼長-可變碼率LDPC\genP.m

?????文件???????5724??2008-12-10?10:20??01吞吐量—不同碼長-可變碼率LDPC\ldpcBER.m

?????文件???????3426??2008-12-10?10:14??01吞吐量—不同碼長-可變碼率LDPC\makeLdpc.m

?????文件???????3849??2008-11-18?10:23??01吞吐量—不同碼長-可變碼率LDPC\makeParityChk.m

?????目錄??????????0??2013-05-17?20:32??01吞吐量—不同碼長-可變碼率LDPC

-----------?---------??----------?-----??----

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