js8::SoftCombiner< N > Class Template Reference

Cache and combine repeated LLR frames for the same decode candidate. More...

#include <soft_combiner.h>

Classes
struct	Key
	Lookup key describing a decode candidate. More...
struct	Combined
	Result returned by combine() describing combined LLRs. More...

Public Member Functions
	SoftCombiner ()
	Construct a SoftCombiner with defaults.
	SoftCombiner (bool enabled, bool runSelfTest=true)
	Construct a SoftCombiner with explicit enable flag.
Key	makeKey (int mode, float f1, float dt, std::array< float, N > const &llr0, std::array< float, N > const &llr1) const
	Create a Key for a candidate from its parameters and LLRs.
Combined	combine (Key const &key, std::array< float, N > const &llr0, std::array< float, N > const &llr1, std::chrono::seconds ttl)
	Attempt to combine incoming LLRs with cached repeats.
void	markDecoded (Key const &key)
	Remove cached repeats for a candidate that has been decoded.
void	flush (std::chrono::seconds ttl)
	Remove cached entries older than ttl.

Detailed Description

template<std::size_t N>
class js8::SoftCombiner< N >

Cache and combine repeated LLR frames for the same decode candidate.

Uses a coarse freq/dt bin and a small LLR signature as the key; repeated receptions accumulate LLRs to improve decode probability without changing over-the-air behavior. The combiner is templated on the LLR length N so the caller binds it to the decoder's bit count. Typical usage:

• Call makeKey() to construct a lookup key for a candidate.
• Call combine() with the candidate's LLRs to accumulate and retrieve combined LLRs and repeat count.

Constructor & Destructor Documentation

SoftCombiner() [1/2]

template<std::size_t N>

js8::SoftCombiner< N >::SoftCombiner ( )

inline

Construct a SoftCombiner with defaults.

The default constructor queries the environment to decide whether soft-combining is enabled.

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SoftCombiner() [2/2]

template<std::size_t N>

js8::SoftCombiner< N >::SoftCombiner ( bool enabled, bool runSelfTest = true )

inlineexplicit

Construct a SoftCombiner with explicit enable flag.

Parameters

enabled	Whether combining is active.
runSelfTest	If true, run a self-test when constructing.

Member Function Documentation

combine()

template<std::size_t N>

Combined js8::SoftCombiner< N >::combine ( Key const & key, std::array< float, N > const & llr0, std::array< float, N > const & llr1, std::chrono::seconds ttl )

inline

Attempt to combine incoming LLRs with cached repeats.

Parameters

key	Candidate key constructed by makeKey().
llr0	LLR0 values for this reception.
llr1	LLR1 values for this reception.
ttl	Time-to-live for cached repeats; older entries are flushed.

Returns

Combined describing the output LLRs and repeat count.

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flush()

template<std::size_t N>

void js8::SoftCombiner< N >::flush ( std::chrono::seconds ttl )

inline

Remove cached entries older than ttl.

Parameters

ttl	Time-to-live; entries not seen within ttl are purged.

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makeKey()

template<std::size_t N>

Key js8::SoftCombiner< N >::makeKey ( int mode, float f1, float dt, std::array< float, N > const & llr0, std::array< float, N > const & llr1 ) const

inline

Create a Key for a candidate from its parameters and LLRs.

Parameters

mode	Submode/mode index.
f1	Frequency estimate (Hz) used to compute a coarse bin.
dt	Timing offset (s) used to compute a coarse bin.
llr0	LLR0 array for the candidate.
llr1	LLR1 array for the candidate.

Returns

Constructed Key with computed signature.

markDecoded()

template<std::size_t N>

void js8::SoftCombiner< N >::markDecoded ( Key const & key )

inline

Remove cached repeats for a candidate that has been decoded.

Parameters

key	Candidate key whose cached entries should be removed.

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The documentation for this class was generated from the following file:

• JS8_Mode/soft_combiner.h