simthlib::TrellisDecoder Class Reference

#include <decoder.h>

Inheritance diagram for simthlib::TrellisDecoder:

[legend]List of all members.

Public Member Functions
	TrellisDecoder (int deviceID, simth::DeviceSystemIntf *system, const simth::PropertyList &pl, std::auto_ptr< TrellisDecodingAlgorithm > algorithm_ptr, simth::SequenceType inType)
virtual	~TrellisDecoder ()
virtual void	decode (const simth::BitSeq &bsin, simth::BitSeq &bsout)
virtual void	decode (const simth::LlvSeq &llv, simth::BitSeq &bsout)
virtual void	decode (const simth::LlrSeq &llr, simth::BitSeq &bsout)
virtual int	getDataLength (int codedLength) const
virtual int	getCodeLength (int rawLength) const
virtual int	dataBitsPerStep () const
virtual int	codedBitsPerStep () const
virtual void	print (std::ostream &os) const

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Detailed Description

This abstract class is a base class of all decoders using a trellis for en/decoding. A special trellis decoder (e.g. a convolutional decoder) just passes a pointer to an appropriate TrellisDecodingAlgorithm (e.g. Viterbi) as argument of the constructor of this class. With this algorithm also a distinct trellis structure is passed to this class.

See also:

TrellisDecodingAlgorithm

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Constructor & Destructor Documentation

simthlib::TrellisDecoder::TrellisDecoder (  int  deviceID, simth::DeviceSystemIntf *  system, const simth::PropertyList &  pl, std::auto_ptr< TrellisDecodingAlgorithm >  algorithm_ptr, simth::SequenceType  inType )

Class constructor: the parameter type std::auto_ptr<Trellis> enables a 'destructive copy semantic' (see B. Stroustrup 'The C++ programming language', Ch. 14.4.2). It is important that the DecodingAlgorithm object pointed to by usedAlgorithm is constructed on the heap. Due to the auto_ptr this class takes the ownership of these objects and the object will be deleted automatically when this class is destructed itself.

virtual simthlib::TrellisDecoder::~TrellisDecoder (   )  [virtual]

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Member Function Documentation

virtual int simthlib::TrellisDecoder::codedBitsPerStep (   )  const [inline, virtual]

Returns the coded output bits per step of the associated encoder, i.e. the number of input bits per step of this decoder. Implements simthlib::StreamDecoder.

virtual int simthlib::TrellisDecoder::dataBitsPerStep (   )  const [inline, virtual]

Returns the number of uncoded data input bits per step of the associated encoder, i.e. the number of data output bits per step of this decoder. Implements simthlib::StreamDecoder.

virtual void simthlib::TrellisDecoder::decode (  const simth::LlrSeq &  llr, simth::BitSeq &  bsout )  [virtual]

Performs a maximum likelihood sequence estimation based on the log-likelihood ratios given by the demodulator (the received modulation symbols) (soft decision decoding). Implements simthlib::Decoder. Reimplemented in simthlib::PunctConvDecoder.

virtual void simthlib::TrellisDecoder::decode (  const simth::LlvSeq &  llv, simth::BitSeq &  bsout )  [virtual]

Performs a maximum likelihood sequence estimation of the data sequence based on the log-likelihood values of the given (the received) modulation symbols (soft decision decoding) Implements simthlib::Decoder. Reimplemented in simthlib::PunctConvDecoder.

virtual void simthlib::TrellisDecoder::decode (  const simth::BitSeq &  bsin, simth::BitSeq &  bsout )  [virtual]

Decodes a bit sequence (hard decision decoding). Implements simthlib::Decoder. Reimplemented in simthlib::PunctConvDecoder.

int simthlib::TrellisDecoder::getCodeLength (  int  rawLength  )  const [inline, virtual]

Returns the length of a coded bit sequence which is generated by the coder from a raw data sequence of the given length. Parameters: rawLength  length of the data sequence Returns: allocated length of the coded sequence Implements simthlib::Decoder. Reimplemented in simthlib::PunctConvDecoder.

int simthlib::TrellisDecoder::getDataLength (  int  codedLength  )  const [inline, virtual]

Returns the length of a data bit sequence which is encoded by the coder from a coded bit sequence of the given length Parameters: codedLength  length of the coded sequence Returns: allocated length of the encoded data sequence Implements simthlib::Decoder. Reimplemented in simthlib::PunctConvDecoder.

virtual void simthlib::TrellisDecoder::print (  std::ostream &  os  )  const [virtual]

Reimplemented from simthlib::Decoder.

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