From 8a4f546b85d0887d1d5af0a428753c7d31304b72 Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Sat, 17 May 2014 17:48:22 +0200 Subject: add non-working PFT layer --- src/dabOutput/edi/PFT.cpp | 91 +++++++++++++++++++++++++++++++++++++++++++++++ src/dabOutput/edi/PFT.h | 77 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 168 insertions(+) create mode 100644 src/dabOutput/edi/PFT.cpp create mode 100644 src/dabOutput/edi/PFT.h (limited to 'src/dabOutput/edi') diff --git a/src/dabOutput/edi/PFT.cpp b/src/dabOutput/edi/PFT.cpp new file mode 100644 index 0000000..e14a008 --- /dev/null +++ b/src/dabOutput/edi/PFT.cpp @@ -0,0 +1,91 @@ +/* + Copyright (C) 2013 Matthias P. Braendli + http://mpb.li + + EDI output, + Protection, Fragmentation and Transport. (PFT) + + Are supported: + Reed-Solomon and Fragmentation + + This implements part of PFT as defined ETSI TS 102 821. + + */ +/* + This file is part of CRC-DabMux. + + CRC-DabMux is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as + published by the Free Software Foundation, either version 3 of the + License, or (at your option) any later version. + + CRC-DabMux is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with CRC-DabMux. If not, see . + */ + +#include "config.h" +#include +#include +#include +#include "PFT.h" +#include "ReedSolomon.h" + +using namespace std; + +typedef vector Chunk; + + +RSPacket PFT::Protect(AFPacket af_packet) +{ + RSPacket rs_packet; + + m_num_chunks = af_packet.size() / 207 + 1; + const size_t zero_pad = m_num_chunks * m_k - af_packet.size(); + + // add zero padding to last chunk + for (size_t i = 0; i < zero_pad; i++) { + af_packet.push_back(0); + } + + for (size_t i = 1; i < af_packet.size(); i+= m_k) { + // add new chunk to the list + Chunk c(m_k + ParityBytes); + + for (size_t j = 0; j < m_k; j++) { + c[j] = af_packet[i+j]; + } + + // calculate RS for chunk + m_encoder.encode(&c.front(), c.size()); + + rs_packet.insert(rs_packet.end(), c.begin(), c.end()); + } + + return rs_packet; +} + +vector< vector > PFT::ProtectAndFragment(AFPacket af_packet) +{ + RSPacket rs_packet = Protect(af_packet); + + const size_t max_payload_size = ( m_num_chunks * ParityBytes ) / (m_m + 1); + + const size_t fragment_size = m_num_chunks * (m_k + ParityBytes) / max_payload_size; + const size_t num_fragments = m_num_chunks * (m_k + ParityBytes) / fragment_size; + + vector< vector > fragments(num_fragments); + + for (size_t i = 0; i < num_fragments; i++) { + for (size_t j = 0; j < fragment_size; j++) { + fragments[i][j] = rs_packet[j*num_fragments + i]; //TODO that's wrong. fix it. + } + } + + return fragments; +} + diff --git a/src/dabOutput/edi/PFT.h b/src/dabOutput/edi/PFT.h new file mode 100644 index 0000000..713170f --- /dev/null +++ b/src/dabOutput/edi/PFT.h @@ -0,0 +1,77 @@ +/* + Copyright (C) 2013 Matthias P. Braendli + http://mpb.li + + EDI output, + Protection, Fragmentation and Transport. (PFT) + + Are supported: + Reed-Solomon and Fragmentation + + This implements part of PFT as defined ETSI TS 102 821. + + */ +/* + This file is part of CRC-DabMux. + + CRC-DabMux is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as + published by the Free Software Foundation, either version 3 of the + License, or (at your option) any later version. + + CRC-DabMux is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with CRC-DabMux. If not, see . + */ + +#ifndef _PFT_H_ +#define _PFT_H_ + +#include "config.h" +#include +#include +#include +#include "AFPacket.h" +#include "Log.h" +#include "ReedSolomon.h" + +typedef std::vector RSPacket; + +class PFT +{ + public: + static const int ParityBytes = 255 - 207; + + PFT(unsigned int RSDataWordLength, unsigned int NumRecoverableFragments) : + m_k(RSDataWordLength), m_m(NumRecoverableFragments), m_encoder(255, 207) + { + if (m_m > 5) { + etiLog.level(warn) << + "EDI PFT: high number of recoverable fragments" + " may lead to large overhead"; + // See TS 102 821, 7.2.1 Known values, list entry for 'm' + } + } + + // Apply Reed-Solomon FEC to the AF Packet + RSPacket Protect(AFPacket af_packet); + + // Cut a RSPacket into several fragments that can be transmitted + std::vector< std::vector > ProtectAndFragment(AFPacket af_packet); + + private: + unsigned int m_k; // length of RS data word + unsigned int m_m; // number of fragments that can be recovered if lost + + size_t m_num_chunks; + + ReedSolomon m_encoder; + +}; + +#endif + -- cgit v1.2.3