Merge branch 'dsssframe64-dev'

examples/dsssframe64sync_example.c

@@ -0,0 +1,97 @@
+// This example demonstrates the basic interface to the dsssframe64gen and
+// dsssframe64sync objects.
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <time.h>
+#include <getopt.h>
+#include <assert.h>
+
+#include "liquid.h"
+
+// static callback function
+static int callback(unsigned char *  _header,
+                    int              _header_valid,
+                    unsigned char *  _payload,
+                    unsigned int     _payload_len,
+                    int              _payload_valid,
+                    framesyncstats_s _stats,
+                    void *           _context)
+{
+    printf("*** callback invoked (%s) ***\n", _payload_valid ? "pass" : "FAIL");
+    framesyncstats_print(&_stats);
+
+    // save recovered symbols to file
+    unsigned int i;
+    FILE * fid = (FILE*)_context;
+    for (i=0; i<_stats.num_framesyms; i++) {
+        fprintf(fid,"s(%3u) = %12.8f + %12.8fj;\n", i+1,
+            crealf(_stats.framesyms[i]), cimagf(_stats.framesyms[i]));
+    }
+    return 0;
+}
+
+int main(int argc, char *argv[])
+{
+    // options
+    unsigned int nfft  = 2400;
+    float        SNRdB =   -10.0f;
+    const char * filename = "dsssframe64sync_example.m";
+
+    // create dsssframe64gen object
+    dsssframe64gen fg = dsssframe64gen_create();
+
+    // generate the frame in blocks
+    unsigned int  buf_len = dsssframe64gen_get_frame_len(fg);
+    float complex * buf_tx = (float complex *)malloc(buf_len*sizeof(float complex));
+    float complex * buf_rx = (float complex *)malloc(buf_len*sizeof(float complex));
+
+    // export results to file
+    FILE * fid = fopen(filename,"w");
+    fprintf(fid,"%% %s : auto-generated file\n", filename);
+    fprintf(fid,"clear all; close all;\n");
+    fprintf(fid,"s=[];\n");
+
+    // generate in one step (for now)
+    dsssframe64gen_execute(fg, NULL, NULL, buf_tx);
+
+    // apply channel (AWGN)
+    float nstd = powf(10.0f,-SNRdB/20.0f);
+    unsigned int i;
+    for (i=0; i<buf_len; i++)
+        buf_rx[i] = buf_tx[i]*M_SQRT1_2 + nstd*(randnf() + _Complex_I*randnf())/M_SQRT2;
+
+    // run through sync
+    dsssframe64sync fs = dsssframe64sync_create(callback, (void*)fid);
+    dsssframe64sync_execute(fs, buf_rx, buf_len);
+    dsssframe64sync_destroy(fs);
+
+    // push resulting sample through periodogram
+    spgramcf periodogram = spgramcf_create_default(nfft);
+    spgramcf_write(periodogram, buf_rx, buf_len);
+    float psd[nfft];
+    spgramcf_get_psd(periodogram, psd);
+    spgramcf_destroy(periodogram);
+
+    // plot results
+    fprintf(fid,"nfft=%u; Y=zeros(1,nfft);\n", nfft);
+    for (i=0; i<nfft; i++)
+        fprintf(fid,"Y(%4u) = %12.8f;\n", i+1, psd[i]);
+    fprintf(fid,"figure('position',[100 100 1200 400]);\n");
+    fprintf(fid,"subplot(1,5,1:3);\n");
+    fprintf(fid,"  f=[0:(nfft-1)]/nfft-0.5; plot(f,Y); xlim([-0.5 0.5]); grid on;\n");
+    fprintf(fid,"  xlabel('Normalized Frequency [f/Fs]'); ylabel('PSD [dB]');\n");
+    fprintf(fid,"subplot(1,5,4:5);\n");
+    fprintf(fid,"  plot(real(s),imag(s),'.','MarkerSize',6); grid on; axis([-1 1 -1 1]*1.5)\n");
+    fprintf(fid,"  axis('square'); xlabel('I'); ylabel('Q');\n");
+    fclose(fid);
+    printf("results written to %s\n", filename);
+
+    // destroy allocated objects and free memory
+    dsssframe64gen_destroy(fg);
+    free(buf_tx);
+    free(buf_rx);
+    return 0;
+}
+

examples/dsssframe64sync_performance_example.c

@@ -0,0 +1,101 @@
+// This example tests the performance for detecting and decoding frames
+// with the dsssframe64gen and dsssframe64sync objects.
+// SEE ALSO: dsssframe64sync_example.c
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include "liquid.h"
+#define OUTPUT_FILENAME  "dsssframe64sync_performance_example.m"
+
+// add noise to channel
+void frame64_add_noise(float complex * _buf,
+        unsigned int _buf_len, float _SNRdB)
+{
+    float nstd = powf(10.0f, -_SNRdB/20.0f);
+    nstd *= M_SQRT2; // scale noise to account for signal being over-sampled by 2
+    unsigned int i;
+    for (i=0; i<_buf_len; i++)
+        _buf[i] += nstd*( randnf() + _Complex_I*randnf() ) * M_SQRT1_2;
+}
+
+int main(int argc, char*argv[])
+{
+    // create frame generator, synchronizer objects
+    dsssframe64gen  fg = dsssframe64gen_create();
+    dsssframe64sync fs = dsssframe64sync_create(NULL,NULL);
+    unsigned int min_errors =    5;
+    unsigned int min_trials =   80;
+    unsigned int max_trials = 1000;
+
+    // create buffer for the frame samples
+    unsigned int  frame_len = dsssframe64gen_get_frame_len(fg);
+    float complex * frame = (float complex *)malloc(frame_len*sizeof(float complex));
+    float SNRdB = -25.0f;
+    FILE* fid = fopen(OUTPUT_FILENAME, "w");
+    fprintf(fid,"%% %s: auto-generated file\n", OUTPUT_FILENAME);
+    fprintf(fid,"clear all; close all;\n");
+    fprintf(fid,"SNR=[]; pdetect=[]; pvalid=[];\n");
+    printf("# %8s %6s (%7s) %6s (%7s) %6s\n", "SNR", "missed", "percent", "errors", "percent", "trials");
+    fclose(fid);
+    while (SNRdB <  -5.0f) {
+        dsssframe64sync_reset_framedatastats(fs);
+        unsigned int num_trials = 0, num_errors = 0;
+        while (1) {
+            unsigned int i;
+            for (i=0; i<min_trials; i++) {
+                // reset frame synchronizer
+                dsssframe64sync_reset(fs);
+
+                // generate the frame with random header and payload
+                dsssframe64gen_execute(fg, NULL, NULL, frame);
+
+                // add channel effects
+                frame64_add_noise(frame, frame_len, SNRdB);
+
+                // synchronize/receive the frame
+                dsssframe64sync_execute(fs, frame, frame_len);
+            }
+            num_trials += min_trials;
+            num_errors = num_trials - dsssframe64sync_get_framedatastats(fs).num_payloads_valid;
+            if (num_errors >= min_errors)
+                break;
+            if (num_trials >= max_trials)
+                break;
+        }
+        // print results
+        framedatastats_s stats = dsssframe64sync_get_framedatastats(fs);
+        unsigned int num_misses = num_trials - stats.num_frames_detected;
+        float pmd = (float) num_misses / (float) num_trials;
+        float per = (float) num_errors / (float) num_trials;
+        printf("  %8.3f %6u (%6.2f%%) %6u (%6.2f%%) %6u\n",
+            SNRdB,num_misses,pmd*100,num_errors,per*100,num_trials);
+        fid = fopen(OUTPUT_FILENAME,"a");
+        fprintf(fid,"SNR(end+1)=%g; pdetect(end+1)=%12g; pvalid(end+1)=%12g;\n",
+                SNRdB,
+                (float)stats.num_frames_detected / (float)num_trials,
+                (float)stats.num_payloads_valid  / (float)num_trials);
+        fclose(fid);
+        if (num_errors < min_errors)
+            break;
+        SNRdB += 1.0f;
+    }
+    fid = fopen(OUTPUT_FILENAME,"a");
+    fprintf(fid,"figure;\n");
+    fprintf(fid,"hold on;\n");
+    fprintf(fid,"  semilogy(SNR, 1-pdetect+eps,'-o', 'LineWidth',2, 'MarkerSize',2);\n");
+    fprintf(fid,"  semilogy(SNR, 1-pvalid +eps,'-o', 'LineWidth',2, 'MarkerSize',2);\n");
+    fprintf(fid,"hold off;\n");
+    fprintf(fid,"xlabel('SNR [dB]');\n");
+    fprintf(fid,"ylabel('Prob. of Error');\n");
+    fprintf(fid,"legend('detect','decoding','location','northeast');\n");
+    fprintf(fid,"axis([-30 10 1e-3 1]);\n");
+    fprintf(fid,"grid on;\n");
+    fclose(fid);
+    printf("results written to %s\n", OUTPUT_FILENAME);
+
+    // clean up allocated objects and memory blocks
+    dsssframe64gen_destroy(fg);
+    dsssframe64sync_destroy(fs);
+    free(frame);
+    return 0;
+}

include/liquid.h

@@ -5993,6 +5993,83 @@ int dsssframesync_debug_disable       (dsssframesync _q);
 int dsssframesync_debug_print         (dsssframesync _q, const char * _filename);
 framedatastats_s dsssframesync_get_framedatastats  (dsssframesync _q);
 
+//
+// Direct sequence/spread spectrum framing with fixed 64-byte payload
+//
+
+// frame generator object type
+typedef struct dsssframe64gen_s * dsssframe64gen;
+
+// create dsssframe64gen object
+dsssframe64gen dsssframe64gen_create();
+
+// copy object
+dsssframe64gen dsssframe64gen_copy(dsssframe64gen q_orig);
+
+// destroy dsssframe64gen object
+int dsssframe64gen_destroy(dsssframe64gen _q);
+
+// print dsssframe64gen object internals
+int dsssframe64gen_print(dsssframe64gen _q);
+
+// get length of assembled frame (samples)
+unsigned int dsssframe64gen_get_frame_len(dsssframe64gen _q);
+
+// generate a frame
+//  _q          :   frame generator object
+//  _header     :   8-byte header data, NULL for random
+//  _payload    :   64-byte payload data, NULL for random
+//  _frame      :   output frame samples, [size: dsssframegen64gen_get_frame_len() x 1]
+int dsssframe64gen_execute(dsssframe64gen         _q,
+                           const unsigned char *  _header,
+                           const unsigned char *  _payload,
+                           liquid_float_complex * _buf);
+
+// get full frame length [samples]
+unsigned int dsssframe64gen_get_frame_len(dsssframe64gen _q);
+
+// frame synchronizer object type
+typedef struct dsssframe64sync_s * dsssframe64sync;
+
+dsssframe64sync dsssframe64sync_create(framesync_callback _callback, void * _userdata);
+
+// copy object
+dsssframe64sync dsssframe64sync_copy(dsssframe64sync q_orig);
+
+int dsssframe64sync_destroy             (dsssframe64sync _q);
+int dsssframe64sync_print               (dsssframe64sync _q);
+int dsssframe64sync_reset               (dsssframe64sync _q);
+int dsssframe64sync_is_frame_open       (dsssframe64sync _q);
+int dsssframe64sync_set_callback(dsssframe64sync    _q,
+                                 framesync_callback _callback);
+int dsssframe64sync_set_context(dsssframe64sync _q,
+                                void *          _context);
+// execute frame synchronizer
+//  _q       : frame synchronizer object
+//  _buf     : input sample array, shape: (_buf_len,)
+//  _buf_len : number of input samples
+int dsssframe64sync_execute(dsssframe64sync _q, liquid_float_complex * _buf, unsigned int _buf_len);
+
+// get detection threshold
+float dsssframe64sync_get_threshold(dsssframe64sync _q);
+
+// set detection threshold
+int dsssframe64sync_set_threshold(dsssframe64sync _q,
+                                  float           _threshold);
+
+// get carrier offset search range [radians/sample]
+float dsssframe64sync_get_range(dsssframe64sync _q);
+
+// set carrier offset search range
+int dsssframe64sync_set_range(dsssframe64sync _q,
+                              float           _dphi_max);
+
+// reset frame data statistics
+int dsssframe64sync_reset_framedatastats(dsssframe64sync _q);
+
+// retrieve frame data statistics
+framedatastats_s dsssframe64sync_get_framedatastats(dsssframe64sync _q);
+
 //
 // OFDM flexframe generator
 //

makefile.in

@@ -632,6 +632,8 @@ framing_objects :=						\
 	src/framing/src/bpacketgen.o				\
 	src/framing/src/bpacketsync.o				\
 	src/framing/src/detector_cccf.o				\
+	src/framing/src/dsssframe64gen.o			\
+	src/framing/src/dsssframe64sync.o			\
 	src/framing/src/dsssframegen.o				\
 	src/framing/src/dsssframesync.o				\
 	src/framing/src/framedatastats.o			\
@@ -680,6 +682,7 @@ framing_autotests :=						\
 	src/framing/tests/bpacketsync_autotest.c		\
 	src/framing/tests/bsync_autotest.c			\
 	src/framing/tests/detector_autotest.c			\
+	src/framing/tests/dsssframe64_autotest.c		\
 	src/framing/tests/dsssframesync_autotest.c		\
 	src/framing/tests/flexframesync_autotest.c		\
 	src/framing/tests/framesync64_autotest.c		\
@@ -1514,6 +1517,8 @@ example_programs :=						\
 	examples/cvsd_example					\
 	examples/detector_cccf_example				\
 	examples/dds_cccf_example				\
+	examples/dsssframe64sync_performance_example		\
+	examples/dsssframe64sync_example			\
 	examples/dsssframesync_example				\
 	examples/dotprod_rrrf_example				\
 	examples/dotprod_cccf_example				\