From f374ae415c7c94f4889535c83c65f0aa770cc221 Mon Sep 17 00:00:00 2001
From: Andre Puschmann <andre.puschmann@tu-ilmenau.de>
Date: Fri, 10 Apr 2015 11:19:21 +0200
Subject: [PATCH] add variable to define maximum number of symbols and frame
 complete indication

---
 lib/ofdm_decode_mac.cc | 30 ++++++++++++++++++++----------
 lib/ofdm_mapper.cc     |  4 ++--
 lib/utils.h            |  2 ++
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/lib/ofdm_decode_mac.cc b/lib/ofdm_decode_mac.cc
index 8f2a21a..22fb428 100644
--- a/lib/ofdm_decode_mac.cc
+++ b/lib/ofdm_decode_mac.cc
@@ -61,6 +61,7 @@ ofdm_decode_mac_impl(bool log, bool debug) : block("ofdm_decode_mac",
 		50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
 		60, 61, 62, 63};
 	qam64.set(cvec(QAM64_D, 64), ivec(qam64_bits, 64));
+	d_frame_complete = true;
 }
 
 int general_work (int noutput_items, gr_vector_int& ninput_items,
@@ -82,6 +83,12 @@ int general_work (int noutput_items, gr_vector_int& ninput_items,
 			pmt::string_to_symbol("ofdm_start"));
 
 		if(tags.size()) {
+			if (d_frame_complete == false) {
+				dout << "Warning: starting to receive new frame before old frame was complete" << std::endl;
+				dout << "Already copied " << copied << " out of " << tx.n_sym << " symbols of last frame" << std::endl;
+			}
+			d_frame_complete = false;
+
 			pmt::pmt_t tuple = tags[0].value;
 			int len_data = pmt::to_uint64(pmt::car(tuple));
 			int encoding = pmt::to_uint64(pmt::cdr(tuple));
@@ -89,19 +96,19 @@ int general_work (int noutput_items, gr_vector_int& ninput_items,
 			ofdm = ofdm_param((Encoding)encoding);
 			tx = tx_param(ofdm, len_data);
 
-			copied = 0;
-
-			// this frame is garbage
-			if(tx.n_sym > 100) {
-				// FIXME: make this nicer, this way garbage frames are skipped
-				copied = tx.n_sym + 1;
+			// sanity check, more than MAX_NUM_SYM may indicate garbage
+			if(tx.n_sym < MAX_NUM_SYM) {
+				copied = 0;
+				dout << "Decode MAC: frame start -- len " << len_data
+					<< "  symbols " << tx.n_sym << "  encoding "
+					<< encoding << std::endl;
+			} else {
+				dout << "Dropping frame with " << tx.n_sym << " symbols, maximum number of symbols is " << MAX_NUM_SYM << std::endl;
 			}
-			dout << "Decode MAC: frame start -- len " << len_data
-				<< "  symbols " << tx.n_sym << "  encoding "
-				<< encoding << std::endl;
 		}
 
 		if(copied < tx.n_sym) {
+			dout << "copy one symbol, copied " << copied << " out of " << tx.n_sym << std::endl;
 			std::memcpy(sym + (copied * 48), in, 48 * sizeof(gr_complex));
 			copied++;
 
@@ -110,6 +117,7 @@ int general_work (int noutput_items, gr_vector_int& ninput_items,
 				decode();
 				in += 48;
 				i++;
+				d_frame_complete = true;
 				break;
 			}
 		}
@@ -300,12 +308,14 @@ private:
 	double deinter[1000 * 48];
 	char out_bits[40000];
 	char out_bytes[40000];
-        bvec decoded_bits;
+	bvec decoded_bits;
 	bool   d_debug;
 	bool   d_log;
+
 	tx_param tx;
 	ofdm_param ofdm;
 	int copied;
+	bool d_frame_complete;
 
 	Modulator<std::complex<double> > bpsk;
 	Modulator<std::complex<double> > qpsk;
diff --git a/lib/ofdm_mapper.cc b/lib/ofdm_mapper.cc
index ebf0175..a721086 100644
--- a/lib/ofdm_mapper.cc
+++ b/lib/ofdm_mapper.cc
@@ -82,8 +82,8 @@ int general_work(int noutput, gr_vector_int& ninput_items,
 
 			// ############ INSERT MAC STUFF
 			tx_param tx(d_ofdm, psdu_length);
-			if(tx.n_sym > 120) {
-				std::cout << "packet too large" <<std::endl;
+			if(tx.n_sym > MAX_NUM_SYM) {
+				std::cout << "packet too large, maximum number of symbols is " << MAX_NUM_SYM << std::endl;
 				return 0;
 			}
 
diff --git a/lib/utils.h b/lib/utils.h
index 69269ae..5bd1eb7 100644
--- a/lib/utils.h
+++ b/lib/utils.h
@@ -23,6 +23,8 @@
 #include <cinttypes>
 #include <iostream>
 
+#define MAX_NUM_SYM 520 // this should be enough to transmit 1500B user payload with BPSK 1/2
+
 #define dout d_debug && std::cout
 
 #if defined(HAVE_LOG4CPP) && defined(ENABLE_GR_LOG)