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Subblock : 1, 2 or 4 sliding windows
Frame or subframe (length < 5114)
First subblock
Middle subblock
Middle subblock
Middle subblock
Last subblock
Beta
Prolog
portion
Alpla
Prolog
portion
Reliability
portion
Prolog
Only used in SP mode.
in SA mode, start from
known state 0
Prolog
Only used in SP mode
Sliding Window
Sliding Window
Sliding Window
Sliding Window
subframes (not last).
in SA mode and SP
mode last subframe,
use tail symbols
8.2SubframeSegmentation(SPmodeonly)
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Architecture
Figure96.SlidingWindowsandSub-blocksSegmentation(Examplewith5Sub-blocks,framelength
≤20730)
Figure96showdiagramsfortheslidingwindowsforbothalphaandbeta.Eachslidingwindowconsistsof
areliabilitysectionandaprologsection.Thesizeofthereliabilitysectioncanrangefrom40to128and
thesizeoftheprologsectioncanrangefrom4to48intheTCP2.Thealphaslidingwindowstartsatthe
leftandgoesright(forwardorder)andthebetaslidingwindowstartsattherightandgoesleft(reverse
order).SeeTable40forthenumberofsub-blocksandslidingwindows.
Table40.ExamplesforNUM_BLOCK,NUM_SUBBLOCK,NUM_SW,andWIN_REL
NUM_BLOCKNUM_SUBBLOCKNUM_SWWIN_REL
401040
12810128
1291165
25611128
2572165
51221128
3840151128
16122631128
20730811128
Aframeneedstobesegmentedintosubframeswhenworkinginsharedprocessing(SP)mode;therefore,
theminimumnumberofsubframesis2.Thesubframelengthshouldbechosensothatithasareliable
portionthatisbothlessthan20480andalsoamultipleof256.Figure97showsthesegmentation.
Eachsubframeisthenfurtherdividedintosub-blocksandslidingwindowsasdescribedinSection8.1.All
subframesexceptthelastonemusthavethesamelengthandbeamultipleof256.
SPRUGK1–March2009TMS320C6457Turbo-DecoderCoprocessor261
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