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ofdm_parse_mac: calculate error rate based on sequence numbers

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This commit is contained in:
Andre Puschmann
2015-04-13 14:16:12 +02:00
parent 77137be0c6
commit 466383137f
2 changed files with 38 additions and 2 deletions
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grc/ieee802_11_ofdm_parse_mac.xml
+6
View File
@@ -44,5 +44,11 @@
<type>message</type>
</sink>
<source>
<name>fer</name>
<type>message</type>
<optional>1</optional>
</source>
</block>
lib/ofdm_parse_mac.cc
+32 -2
View File
@@ -23,6 +23,8 @@
using namespace gr::ieee802_11;
#define FER_ALPHA 0.2f
class ofdm_parse_mac_impl : public ofdm_parse_mac {
public:
@@ -36,6 +38,10 @@ ofdm_parse_mac_impl(bool log, bool debug) :
message_port_register_in(pmt::mp("in"));
set_msg_handler(pmt::mp("in"), boost::bind(&ofdm_parse_mac_impl::parse, this, _1));
message_port_register_out(pmt::mp("fer"));
d_last_fer = 0.0f;
d_last_seq_no = 0;
}
~ofdm_parse_mac_impl() {
@@ -251,13 +257,36 @@ void parse_data(char *buf, int length) {
}
dout << std::endl;
dout << "seq nr: " << int(h->seq_nr >> 4) << std::endl;
int seq_no = int(h->seq_nr >> 4);
dout << "seq nr: " << seq_no << std::endl;
dout << "mac 1: ";
print_mac_address(h->addr1, true);
dout << "mac 2: ";
print_mac_address(h->addr2, true);
dout << "mac 3: ";
print_mac_address(h->addr3, true);
int lost_frames = seq_no - d_last_seq_no - 1;
dout << "d_last_seq_no: " << d_last_seq_no << std::endl;
dout << "lost frames: " << lost_frames << std::endl;
// calculate instantaneous error rate
float curr_fer = 0.0f;
if (lost_frames > 0)
curr_fer = 1 - (1 / (static_cast<float>(lost_frames) + 1));
dout << "instantaneous fer: " << curr_fer << std::endl;
// update FER estimate
float fer = (1.0f - FER_ALPHA) * d_last_fer + FER_ALPHA * curr_fer;
dout << "rolling fer: " << fer << std::endl;
// keep track of values
d_last_seq_no = seq_no;
d_last_fer = fer;
// publish FER estimate
pmt::pmt_t pdu = pmt::make_f32vector(1, fer * 100);
message_port_pub(pmt::mp("fer"), pmt::cons( pmt::PMT_NIL, pdu ));
}
void parse_control(char *buf, int length) {
@@ -341,7 +370,8 @@ void print_ascii(char* buf, int length) {
private:
bool d_log;
bool d_debug;
float d_last_fer;
int d_last_seq_no;
};
ofdm_parse_mac::sptr