From 18276a5d2eac39b08caa2ce44e196e7a98f1a108 Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Sat, 30 Dec 2017 09:55:45 +0100 Subject: Calculate PAPR in the OfdmGenerator --- Makefile.am | 2 ++ doc/example.ini | 4 ++-- src/OfdmGenerator.cpp | 30 +++++++++++++++++++++++------- src/OfdmGenerator.h | 8 ++++++-- src/PAPRStats.cpp | 2 +- src/PAPRStats.h | 2 +- 6 files changed, 35 insertions(+), 13 deletions(-) diff --git a/Makefile.am b/Makefile.am index 54ae62e..1880acd 100644 --- a/Makefile.am +++ b/Makefile.am @@ -136,6 +136,8 @@ odr_dabmod_SOURCES = src/DabMod.cpp \ src/Utils.h \ src/TII.cpp \ src/TII.h \ + src/PAPRStats.cpp \ + src/PAPRStats.h \ src/zmq.hpp \ lib/crc.h \ lib/crc.c \ diff --git a/doc/example.ini b/doc/example.ini index ec0525c..b3faffd 100644 --- a/doc/example.ini +++ b/doc/example.ini @@ -141,11 +141,11 @@ rate=2048000 enable=0 ; At what amplitude the signal should be clipped -clip=70.0 +clip=50.0 ; How much to clip the error signal used to compensate the effect ; of clipping -error_clip=0.05 +error_clip=0.1 [firfilter] ; The FIR Filter can be used to create a better spectral quality. diff --git a/src/OfdmGenerator.cpp b/src/OfdmGenerator.cpp index 915d568..1a819ee 100644 --- a/src/OfdmGenerator.cpp +++ b/src/OfdmGenerator.cpp @@ -27,11 +27,8 @@ #include "OfdmGenerator.h" #include "PcDebug.h" -#include -#include "fftw3.h" #define FFT_TYPE fftwf_complex -#include #include #include #include @@ -56,7 +53,10 @@ OfdmGenerator::OfdmGenerator(size_t nbSymbols, myCfr(enableCfr), myCfrClip(cfrClip), myCfrErrorClip(cfrErrorClip), - myCfrFft(nullptr) + myCfrFft(nullptr), + // Initialise the PAPRStats to a few seconds worth of samples + myPaprBeforeCFR(nbSymbols * 50), + myPaprAfterCFR(nbSymbols * 50) { PDEBUG("OfdmGenerator::OfdmGenerator(%zu, %zu, %zu, %s) @ %p\n", nbSymbols, nbCarriers, spacing, inverse ? "true" : "false", this); @@ -71,6 +71,7 @@ OfdmGenerator::OfdmGenerator(size_t nbSymbols, RC_ADD_PARAMETER(clip, "CFR: Clip to amplitude"); RC_ADD_PARAMETER(errorclip, "CFR: Limit error"); RC_ADD_PARAMETER(clip_stats, "CFR: statistics (clip ratio, errorclip ratio)"); + RC_ADD_PARAMETER(papr, "PAPR measurements (before CFR, after CFR)"); if (inverse) { myPosDst = (nbCarriers & 1 ? 0 : 1); @@ -203,19 +204,25 @@ int OfdmGenerator::process(Buffer* const dataIn, Buffer* dataOut) fftwf_execute(myFftPlan); // IFFT from myFftIn to myFftOut + complexf *symbol = reinterpret_cast(myFftOut); + myPaprBeforeCFR.process_block(symbol, mySpacing); + if (myCfr) { if (myMERCalcIndex == i) { before_cfr.resize(mySpacing); memcpy(before_cfr.data(), myFftOut, mySpacing * sizeof(FFT_TYPE)); } - complexf *symbol = reinterpret_cast(myFftOut); /* cfr_one_iteration runs the myFftPlan again at the end, and * therefore writes the output data to myFftOut. */ const auto stat = cfr_one_iteration(symbol, reference.data()); // i == 0 always zero power, so the MER ends up being NaN + if (i > 0) { + myPaprAfterCFR.process_block(symbol, mySpacing); + } + if (i > 0 and myMERCalcIndex == i) { /* MER definition, ETSI ETR 290, Annex C * @@ -358,8 +365,8 @@ void OfdmGenerator::set_parameter(const std::string& parameter, else if (parameter == "errorclip") { ss >> myCfrErrorClip; } - else if (parameter == "clip_stats") { - throw ParameterError("Parameter 'clip_stats' is read-only"); + else if (parameter == "clip_stats" or parameter == "papr") { + throw ParameterError("Parameter '" + parameter + "' is read-only"); } else { stringstream ss_err; @@ -406,6 +413,15 @@ const std::string OfdmGenerator::get_parameter(const std::string& parameter) con "MER after CFR: " << avg_mer << " dB"; } } + else if (parameter == "papr") { + const double papr_before = myPaprBeforeCFR.calculate_papr(); + const double papr_after = myPaprAfterCFR.calculate_papr(); + + ss << "PAPR [dB]: " << std::fixed << + (papr_before == 0 ? string("N/A") : to_string(papr_before)) << + ", " << + (papr_after == 0 ? string("N/A") : to_string(papr_after)); + } else { ss << "Parameter '" << parameter << "' is not exported by controllable " << get_rc_name(); diff --git a/src/OfdmGenerator.h b/src/OfdmGenerator.h index 008d84e..8374cf9 100644 --- a/src/OfdmGenerator.h +++ b/src/OfdmGenerator.h @@ -30,11 +30,11 @@ # include "config.h" #endif -#include "porting.h" #include "ModPlugin.h" #include "RemoteControl.h" +#include "PAPRStats.h" #include "fftw3.h" -#include +#include #include #include @@ -102,6 +102,10 @@ class OfdmGenerator : public ModCodec, public RemoteControllable std::deque myClipRatios; std::deque myErrorClipRatios; + // Measure PAPR before and after CFR + PAPRStats myPaprBeforeCFR; + PAPRStats myPaprAfterCFR; + size_t myMERCalcIndex = 0; std::deque myMERs; }; diff --git a/src/PAPRStats.cpp b/src/PAPRStats.cpp index bf6acc4..2e8bca9 100644 --- a/src/PAPRStats.cpp +++ b/src/PAPRStats.cpp @@ -69,7 +69,7 @@ void PAPRStats::process_block(const complexf* data, size_t data_len) } } -double PAPRStats::calculate_papr() +double PAPRStats::calculate_papr() const { if (m_squared_mean.size() < m_num_blocks_to_accumulate) { return 0; diff --git a/src/PAPRStats.h b/src/PAPRStats.h index 9463a3d..92e5231 100644 --- a/src/PAPRStats.h +++ b/src/PAPRStats.h @@ -64,7 +64,7 @@ class PAPRStats /* Returns PAPR in dB if enough blocks were processed, or * 0 otherwise. */ - double calculate_papr(void); + double calculate_papr(void) const; private: size_t m_num_blocks_to_accumulate; -- cgit v1.2.3