Prepare ofdm files for demod function

git-svn-id: https://svn.code.sf.net/p/freetel/code@3190 01035d8c-6547-0410-b346-abe4f91aad63

diff --git a/codec2-dev/src/codec2_ofdm.h b/codec2-dev/src/codec2_ofdm.h
index 3da37355eccf3bb720e26f19d495edcd3750489d..8484cd88f029f547055db6186ccd7f857c97898c 100644 (file)
--- a/codec2-dev/src/codec2_ofdm.h
+++ b/codec2-dev/src/codec2_ofdm.h
@@ -1,11 +1,29 @@
+/*---------------------------------------------------------------------------*\
+
+  FILE........: codec2_ofdm.h
+  AUTHORS.....: David Rowe & Steve Sampson
+  DATE CREATED: June 2017
+
+ External user references to the modem library.
+
+\*---------------------------------------------------------------------------*/
+
 /*
- * Copyright (C) 2017 David Rowe
- *
- * All rights reserved
- * 
- * Licensed under GNU LGPL V2.1
- * See LICENSE file for information
- */
+  Copyright (C) 2017 David Rowe
+
+  All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License version 2, as
+  published by the Free Software Foundation.  This program 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 Lesser General Public License
+  along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
 
 #ifndef CODEC2_OFDM_H
 #define CODEC2_OFDM_H
@@ -29,8 +47,8 @@ struct OFDM;
 
 struct OFDM *ofdm_create(void);
 void ofdm_destroy(struct OFDM *);
-void ofdm_mod(struct OFDM *ofdm, COMP [OFDM_SAMPLESPERFRAME], const int *);
-int *ofdm_demod(struct OFDM *ofdm, COMP *);
+void ofdm_mod(struct OFDM *, COMP *, const int *);
+void ofdm_demod(struct OFDM *, int *, COMP *);
 
 /* option setters */
 

diff --git a/codec2-dev/src/ofdm.c b/codec2-dev/src/ofdm.c
index a77491cee50f7d0106649dff2b9f858b5a6282c8..420cb942d460367df5460f0a137efc4da5c5130d 100644 (file)
--- a/codec2-dev/src/ofdm.c
+++ b/codec2-dev/src/ofdm.c
@@ -1,11 +1,29 @@
+/*---------------------------------------------------------------------------*\
+
+  FILE........: ofdm.c
+  AUTHORS.....: David Rowe & Steve Sampson
+  DATE CREATED: June 2017
+
+  A Library of functions that implement a BPSK/QPSK OFDM modem
+
+\*---------------------------------------------------------------------------*/
+
 /*
- * Copyright (C) 2017 David Rowe
- *
- * All rights reserved
- *
- * Licensed under GNU LGPL V2.1
- * See LICENSE file for information
- */
+  Copyright (C) 2017 David Rowe
+
+  All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License version 2, as
+  published by the Free Software Foundation.  This program 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 Lesser General Public License
+  along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -20,15 +38,12 @@
 #include "ofdm_internal.h"
 #include "codec2_ofdm.h"
 
-/*
- * Library of functions that implement a BPSK/QPSK OFDM modem
- *
- * Translated from Octave by Steve Sampson
- */
-
 /* Static Prototypes */
 
 static void matrix_vector_multiply(struct OFDM *, complex float *, complex float *);
+static void matrix_vector_conjugate_multiply(struct OFDM *, complex float *, complex float *);
+static complex float vector_sum(complex float *, int, int);
+static complex float vector_conjugate_sum(complex float *, int, int);
 static complex float qpsk_mod(int *);
 static void qpsk_demod(complex float, int *);
 static void ofdm_txframe(struct OFDM *, complex float [OFDM_SAMPLESPERFRAME], complex float *);
@@ -71,10 +86,12 @@ static complex float qpsk_mod(int *bits) {
 
 static void qpsk_demod(complex float symbol, int *bits) {
     complex float rotate = symbol * cexpf(I * (M_PI / 4.0f));
-    bits[0] = crealf(rotate) < 0.0f;
-    bits[1] = cimagf(rotate) < 0.0f;
+    bits[1] = crealf(rotate) < 0.0f;
+    bits[0] = cimagf(rotate) < 0.0f;
 }
 
+/* convert frequency domain into time domain */
+
 static void matrix_vector_multiply(struct OFDM *ofdm, complex float *result, complex float *vector) {
     int row, col;
 
@@ -87,6 +104,44 @@ static void matrix_vector_multiply(struct OFDM *ofdm, complex float *result, com
     }
 }
 
+/* convert time domain into frequency domain */
+
+static void matrix_vector_conjugate_multiply(struct OFDM *ofdm, complex float *result, complex float *vector) {
+    int row, col;
+
+    for (col = 0; col < (OFDM_NC + 2); col++) {
+        result[col] = 0.0f + 0.0f * I;
+
+        for (row = 0; row < OFDM_M; row++) {
+            result[col] += (vector[row] * conjf(ofdm->W[col][row])); /* complex result */
+        }
+    }
+}
+
+static complex float vector_sum(complex float *a, int index, int num_elements) {
+    int i;
+    
+    complex float sum = 0.0f + 0.0f * I;
+
+    for (i = index; i < (index + num_elements); i++) {
+        sum += a[i];
+    }
+
+    return sum;
+}
+
+static complex float vector_conjugate_sum(complex float *a, int index, int num_elements) {
+    int i;
+    
+    complex float sum = 0.0f + 0.0f * I;
+
+    for (i = index; i < (index + num_elements); i++) {
+        sum += conjf(a[i]);
+    }
+
+    return sum;
+}
+
 /*
  * Correlates the OFDM pilot symbol samples with a window of received
  * samples to determine the most likely timing offset.  Combines two
@@ -224,7 +279,7 @@ struct OFDM *ofdm_create() {
        return NULL;
     }
 
-    /* store complex pilot symbols */
+    /* store complex BPSK pilot symbols */
 
     for (i = 0; i < (OFDM_NC + 2); i++) {
         ofdm->pilots[i] = ((float) pilotvalues[i]) + 0.0f * I;
@@ -265,7 +320,6 @@ struct OFDM *ofdm_create() {
 
     /*
      * rate_fs_pilot_samples is 160 samples, as we take the last 16 and copy to the front
-     * Thus resulting in 16 + 128 + 16 = 160
      */
 
     /* first copy the last Cyclic Prefix (CP) values */
@@ -349,7 +403,6 @@ void ofdm_mod(struct OFDM *ofdm, COMP result[OFDM_SAMPLESPERFRAME], const int *t
     }
 }
 
-//function [rx_bits states aphase_est_pilot_log rx_np rx_amp] =
 int *ofdm_demod(struct OFDM *ofdm, COMP *rxbuf_in) {
 /* TODO */
 }

diff --git a/codec2-dev/src/ofdm_internal.h b/codec2-dev/src/ofdm_internal.h
index b01241f56a18539c5bd161749eb8826c8b5f2fb4..5809951f2a117b55d000373d60324f5b7de86131 100644 (file)
--- a/codec2-dev/src/ofdm_internal.h
+++ b/codec2-dev/src/ofdm_internal.h
@@ -1,11 +1,29 @@
+/*---------------------------------------------------------------------------*\
+
+  FILE........: ofdm_internal.h
+  AUTHORS.....: David Rowe & Steve Sampson
+  DATE CREATED: June 2017
+
+  OFDM Internal definitions.
+
+\*---------------------------------------------------------------------------*/
+
 /*
- * Copyright (C) 2017 David Rowe
- *
- * All rights reserved
- * 
- * Licensed under GNU LGPL V2.1
- * See LICENSE file for information
- */
+  Copyright (C) 2017 David Rowe
+
+  All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License version 2, as
+  published by the Free Software Foundation.  This program 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 Lesser General Public License
+  along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
 
 #ifndef OFDM_INTERNAL_H
 #define OFDM_INTERNAL_H
@@ -68,6 +86,12 @@ struct OFDM {
     complex float rxbuf[OFDM_RXBUF];
     complex float pilots[OFDM_NC + 2];
     float w[OFDM_NC + 2];
+    
+    /* Demodulator data */
+
+    float aphase_est_pilot_log[OFDM_NC + 2];
+    float rx_np[OFDM_NC];
+    float rx_amp[OFDM_NC];
 };
 
 #ifdef __cplusplus