diff --git a/grc/gsm_block_tree.xml b/grc/gsm_block_tree.xml
index 1773df3..026d00b 100644
--- a/grc/gsm_block_tree.xml
+++ b/grc/gsm_block_tree.xml
@@ -32,7 +32,8 @@
     <cat>
       <name>Transceiver</name>
       <block>gsm_trx_burst_if</block>
-      <block>gsm_freq_hopping</block>
+      <block>gsm_freq_hopper_tag</block>
+      <block>gsm_freq_hopper_msg</block>
     </cat>
     <cat>
       <name>Logical channels demapping</name>
diff --git a/grc/trx/CMakeLists.txt b/grc/trx/CMakeLists.txt
index 0c7a636..81ef6ed 100644
--- a/grc/trx/CMakeLists.txt
+++ b/grc/trx/CMakeLists.txt
@@ -19,6 +19,7 @@
 
 install(FILES
     gsm_trx_burst_if.xml
-    gsm_freq_hopping.xml
+    gsm_freq_hopper_tag.xml
+    gsm_freq_hopper_msg.xml
     DESTINATION share/gnuradio/grc/blocks
 )
diff --git a/grc/trx/gsm_freq_hopper_msg.xml b/grc/trx/gsm_freq_hopper_msg.xml
new file mode 100644
index 0000000..0175816
--- /dev/null
+++ b/grc/trx/gsm_freq_hopper_msg.xml
@@ -0,0 +1,81 @@
+<?xml version="1.0"?>
+<block>
+  <name>freq_hopper_msg</name>
+  <key>gsm_freq_hopper_msg</key>
+  <import>import grgsm</import>
+  <make>grgsm.freq_hopper_msg($samp_rate, $start_fc_rx, $start_fc_tx, $rx_hopping, $tx_hopping, $freq_change_period)</make>
+<!--  $hopping_cmd-->
+<!--  <callback>set_fn_time_reference($init_fn, $init_time_secs, $init_time_fracs)</callback>-->
+<!--  <param>-->
+<!--    <name>Initial hopping command</name>-->
+<!--    <key>hopping_cmd</key>-->
+<!--    <value>pmt.to_pmt({'cmd': 'start', 'hopping_params': {'hsn': 1, 'maio': 0, 'ma': [1,2,3,4]} })</value>-->
+<!--    <type>raw</type>-->
+<!--    <hide>part</hide>-->
+<!--  </param>-->
+
+  <param>
+    <name>Sample rate</name>
+    <key>samp_rate</key>
+    <value>samp_rate</value>
+    <type>float</type>
+    <hide>part</hide>
+  </param>
+
+  <param>
+    <name>start_fc_rx</name>
+    <key>start_fc_rx</key>
+    <value>fc</value>
+    <type>float</type>
+    <hide>part</hide>
+  </param>
+
+  <param>
+    <name>start_fc_tx</name>
+    <key>start_fc_tx</key>
+    <value>fc</value>
+    <type>float</type>
+    <hide>part</hide>
+  </param>
+
+  <param>
+    <name>rx_hopping</name>
+    <key>rx_hopping</key>
+    <value>True</value>
+    <type>float</type>
+    <hide>part</hide>
+  </param>
+
+  <param>
+    <name>tx_hopping</name>
+    <key>tx_hopping</key>
+    <value>True</value>
+    <type>float</type>
+    <hide>part</hide>
+  </param>
+
+  <param>
+    <name>freq_change_period</name>
+    <key>freq_change_period</key>
+    <value>0.0046</value>
+    <type>float</type>
+    <hide>part</hide>
+  </param>
+
+  <sink>
+    <name>in</name>
+    <type>complex</type>
+  </sink>
+
+<!--  <sink>-->
+<!--    <name>hopping_cmd</name>-->
+<!--    <type>message</type>-->
+<!--    <optional>1</optional>-->
+<!--  </sink>-->
+
+  <source>
+    <name>control</name>
+    <type>message</type>
+    <optional>1</optional>
+  </source>
+</block>
diff --git a/grc/trx/gsm_freq_hopping.xml b/grc/trx/gsm_freq_hopper_tag.xml
similarity index 85%
rename from grc/trx/gsm_freq_hopping.xml
rename to grc/trx/gsm_freq_hopper_tag.xml
index 9e71e53..b9d1372 100644
--- a/grc/trx/gsm_freq_hopping.xml
+++ b/grc/trx/gsm_freq_hopper_tag.xml
@@ -1,9 +1,9 @@
 <?xml version="1.0"?>
 <block>
-  <name>freq_hopping</name>
-  <key>gsm_freq_hopping</key>
+  <name>freq_hopper_tag</name>
+  <key>gsm_freq_hopper_tag</key>
   <import>import grgsm</import>
-  <make>grgsm.freq_hopping($hopping_cmd)</make>
+  <make>grgsm.freq_hopper_tag($hopping_cmd)</make>
 <!--  <callback>set_fn_time_reference($init_fn, $init_time_secs, $init_time_fracs)</callback>-->
   <param>
     <name>Initial hopping command</name>
diff --git a/include/grgsm/trx/CMakeLists.txt b/include/grgsm/trx/CMakeLists.txt
index 0addc79..346a807 100644
--- a/include/grgsm/trx/CMakeLists.txt
+++ b/include/grgsm/trx/CMakeLists.txt
@@ -21,7 +21,8 @@
 # Install public header files
 ########################################################################
 install(FILES
-    freq_hopping.h
+    freq_hopper_tag.h
+    freq_hopper_msg.h
     trx_burst_if.h
     DESTINATION include/grgsm/trx
 )
diff --git a/include/grgsm/trx/freq_hopping.h b/include/grgsm/trx/freq_hopper_msg.h
similarity index 77%
copy from include/grgsm/trx/freq_hopping.h
copy to include/grgsm/trx/freq_hopper_msg.h
index eeb3a53..12a9fe0 100644
--- a/include/grgsm/trx/freq_hopping.h
+++ b/include/grgsm/trx/freq_hopper_msg.h
@@ -21,11 +21,11 @@
  */
 
 
-#ifndef INCLUDED_GSM_FREQ_HOPPING_H
-#define INCLUDED_GSM_FREQ_HOPPING_H
+#ifndef INCLUDED_GSM_FREQ_HOPPER_MSG_H
+#define INCLUDED_GSM_FREQ_HOPPER_MSG_H
 
 #include <grgsm/api.h>
-#include <gnuradio/block.h>
+#include <gnuradio/sync_block.h>
 
 namespace gr {
   namespace gsm {
@@ -35,10 +35,18 @@
      * \ingroup gsm
      *
      */
-    class GRGSM_API freq_hopping : virtual public gr::block
+    class GRGSM_API freq_hopper_msg : virtual public sync_block
     {
      public:
-      typedef boost::shared_ptr<freq_hopping> sptr;
+      typedef boost::shared_ptr<freq_hopper_msg> sptr;
+
+      static sptr make(
+        double samp_rate = 1e6,
+        double start_fc_rx = 1e9,
+        double start_fc_tx = 1e9,
+        bool rx_hopping=true,
+        bool tx_hopping=true,
+        double freq_change_period=0.0046);
 
       /*!
        * hopping_cmd is a pmt dictionary with following fields:
@@ -58,11 +66,9 @@
        *      "n_arfcn": number_of_arfcns_in_ma}
        *  "fn": frame number when to start or stop hopping
        */
-      static sptr make(pmt::pmt_t hopping_cmd);
-      virtual void add_hopping_cmd(pmt::pmt_t hopping_cmd=pmt::PMT_NIL) = 0;
+//      virtual void add_hopping_cmd(pmt::pmt_t hopping_cmd=pmt::PMT_NIL) = 0;
     };
   } // namespace gsm
 } // namespace gr
 
-#endif /* INCLUDED_GSM_FREQ_HOPPING_H */
-
+#endif /* INCLUDED_GSM_FREQ_HOPPER_MSG_H */
diff --git a/include/grgsm/trx/freq_hopping.h b/include/grgsm/trx/freq_hopper_tag.h
similarity index 89%
rename from include/grgsm/trx/freq_hopping.h
rename to include/grgsm/trx/freq_hopper_tag.h
index eeb3a53..fc4f8c3 100644
--- a/include/grgsm/trx/freq_hopping.h
+++ b/include/grgsm/trx/freq_hopper_tag.h
@@ -21,8 +21,8 @@
  */
 
 
-#ifndef INCLUDED_GSM_FREQ_HOPPING_H
-#define INCLUDED_GSM_FREQ_HOPPING_H
+#ifndef INCLUDED_GSM_FREQ_HOPPER_TAG_H
+#define INCLUDED_GSM_FREQ_HOPPER_TAG_H
 
 #include <grgsm/api.h>
 #include <gnuradio/block.h>
@@ -35,10 +35,10 @@
      * \ingroup gsm
      *
      */
-    class GRGSM_API freq_hopping : virtual public gr::block
+    class GRGSM_API freq_hopper_tag : virtual public gr::block
     {
      public:
-      typedef boost::shared_ptr<freq_hopping> sptr;
+      typedef boost::shared_ptr<freq_hopper_tag> sptr;
 
       /*!
        * hopping_cmd is a pmt dictionary with following fields:
@@ -64,5 +64,4 @@
   } // namespace gsm
 } // namespace gr
 
-#endif /* INCLUDED_GSM_FREQ_HOPPING_H */
-
+#endif /* INCLUDED_GSM_FREQ_HOPPER_TAG_H */
diff --git a/lib/trx/CMakeLists.txt b/lib/trx/CMakeLists.txt
index 0bfbe34..cd8f556 100644
--- a/lib/trx/CMakeLists.txt
+++ b/lib/trx/CMakeLists.txt
@@ -19,6 +19,7 @@
 
 add_sources(
     trx_burst_if_impl.cc
-    freq_hopping_impl.cc
+    freq_hopper_tag_impl.cc
+    freq_hopper_msg_impl.cc
 )
 
diff --git a/lib/trx/freq_hopper_msg_impl.cc b/lib/trx/freq_hopper_msg_impl.cc
new file mode 100644
index 0000000..678b577
--- /dev/null
+++ b/lib/trx/freq_hopper_msg_impl.cc
@@ -0,0 +1,273 @@
+/* -*- c++ -*- */
+/* @file
+ * @author Piotr Krysik <ptrkrysik@gmail.com>
+ * @section LICENSE
+ * 
+ * Gr-gsm is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * Gr-gsm 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 General Public License
+ * along with gr-gsm; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ * 
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gnuradio/io_signature.h>
+#include <grgsm/gsmtap.h>
+
+#include "freq_hopper_msg_impl.h"
+#include "../misc_utils/freq_hopping_utils.h"
+extern "C" {
+#include <osmocom/gsm/gsm_utils.h>
+}
+
+namespace gr {
+  namespace gsm {
+    using namespace pmt;
+
+    freq_hopper_msg::sptr
+    freq_hopper_msg::make(
+      double samp_rate,
+      double start_fc_rx,
+      double start_fc_tx,
+      bool rx_hopping,
+      bool tx_hopping,
+      double freq_change_period)
+    {
+      return gnuradio::get_initial_sptr
+        (new freq_hopper_msg_impl(samp_rate, start_fc_rx, start_fc_tx,
+          rx_hopping, tx_hopping, freq_change_period));
+    }
+
+    /*
+     * The private constructor
+     */
+    freq_hopper_msg_impl::freq_hopper_msg_impl(
+      double samp_rate,
+      double start_fc_rx,
+      double start_fc_tx,
+      bool rx_hopping,
+      bool tx_hopping,
+      double freq_change_period) :
+        sync_block("freq_hopper_msg",
+          gr::io_signature::make(1, 1, sizeof(gr_complex)),
+          gr::io_signature::make(0, 0, 0)),
+        d_samp_rate(samp_rate),
+        d_fc_rx(start_fc_rx),
+        d_fc_tx(start_fc_tx),
+        d_rx_hopping(rx_hopping),
+        d_tx_hopping(tx_hopping),
+        d_freq_change_period(freq_change_period),
+        d_rx_time_received(false),
+        d_last_rx_time(0.0),
+        d_current_time(0.0),
+        d_current_start_offset(0.0),
+        d_i(0),
+        d_start_time(1.0),
+        d_next_change_time(time_spec_t(2.0)),
+        d_change_advance(0.15),
+        d_rx_time_key(string_to_symbol("rx_time"))
+//          d_hopping_cmd(PMT_NIL),
+//          d_hopping_enable(false),
+//          d_base_freq(890e6)
+    {
+        // Register I/O ports
+//        message_port_register_in(mp("hopping_cmd"));
+        message_port_register_out(mp("control"));
+//      d_f.push_back(-0.3e6);
+//      d_f.push_back(-0.2e6);
+//      d_f.push_back(-0.1e6);
+//      d_f.push_back(0);
+//      d_f.push_back(0.1e6);
+//      d_f.push_back(0.2e6);
+//      d_f.push_back(0.3e6);
+
+      d_ma.push_back(51);
+      d_ma.push_back(2);
+      d_ma.push_back(37);
+      d_ma.push_back(45);
+      d_hsn = 0;
+      d_maio = 0;
+      d_current_fn = 0;
+//        // Bind message handlers
+//        set_msg_handler(mp("hopping_cmd"),
+//          boost::bind(&freq_hopper_msg_impl::add_hopping_cmd,
+//            this, _1));
+
+//        add_hopping_cmd(hopping_cmd);
+    }
+
+    /*
+     * Our virtual destructor.
+     */
+    freq_hopper_msg_impl::~freq_hopper_msg_impl()
+    {
+    }
+
+    int freq_hopper_msg_impl::work(
+      int noutput_items,
+      gr_vector_const_void_star &input_items,
+      gr_vector_void_star &output_items)
+    {
+      std::vector<tag_t> rx_time_tags;
+      get_tags_in_window(rx_time_tags, 0, 0, noutput_items, d_rx_time_key);
+      if(rx_time_tags.size() > 0){
+        tag_t rx_time_tag = rx_time_tags[0];
+        uint64_t rx_time_full_part = to_uint64(tuple_ref(rx_time_tag.value,0));
+        double rx_time_frac_part = to_double(tuple_ref(rx_time_tag.value,1));
+        d_last_rx_time = time_spec_t(rx_time_full_part, rx_time_frac_part);
+        d_current_start_offset = rx_time_tag.offset;
+        d_rx_time_received = true;
+      }
+      if(d_rx_time_received){
+        uint64_t buffer_end_offset = nitems_read(0) + noutput_items;
+        d_current_time = time_spec_t::from_ticks(buffer_end_offset - d_current_start_offset, d_samp_rate) + d_last_rx_time;
+      }
+
+//    Freq. control messages generation
+      if ((d_current_time.get_real_secs() > d_start_time) &&
+          ((d_next_change_time-d_current_time).get_real_secs() < d_change_advance)){
+        pmt_t freq_change_time_pmt = cons(
+          from_uint64(d_next_change_time.get_full_secs()),
+          from_double(d_next_change_time.get_frac_secs())
+        );
+        d_next_change_time = d_next_change_time + d_freq_change_period;
+        double dsp_freq = get_dsp_freq(d_current_fn);
+        if(d_tx_hopping){
+          pmt_t tx_tune_msg = dict_add(make_dict(), mp("lo_freq"), from_double(d_fc_tx));
+//          tx_tune_msg = dict_add(tx_tune_msg, mp("dsp_freq"), from_double(d_f[d_i % d_f.size()]));
+          tx_tune_msg = dict_add(tx_tune_msg, mp("dsp_freq"), from_double(dsp_freq));
+          tx_tune_msg = dict_add(tx_tune_msg, mp("time"), freq_change_time_pmt);
+          tx_tune_msg = dict_add(tx_tune_msg, mp("direction"), mp("TX"));
+          message_port_pub(mp("control"), tx_tune_msg);
+//          std::cout << "tx: " << tx_tune_msg << std::endl;
+        }
+        if(d_rx_hopping){
+          pmt_t rx_tune_msg = dict_add(make_dict(), mp("lo_freq"), from_double(d_fc_rx));
+//          rx_tune_msg = dict_add(rx_tune_msg, mp("dsp_freq"), from_double(-d_f[d_i % d_f.size()]));
+          rx_tune_msg = dict_add(rx_tune_msg, mp("dsp_freq"), from_double(-dsp_freq));
+          rx_tune_msg = dict_add(rx_tune_msg, mp("time"), freq_change_time_pmt);
+          rx_tune_msg = dict_add(rx_tune_msg, mp("direction"), mp("RX"));
+          message_port_pub(mp("control"), rx_tune_msg);
+//          std::cout << "rx: " << rx_tune_msg << std::endl;
+        }
+        d_i++;
+        d_current_fn++;
+      }
+      return noutput_items;
+    }
+
+    double freq_hopper_msg_impl::get_dsp_freq(uint64_t fn){ //TODO: jak otrzymac fn
+      int mai = calculate_ma_sfh(d_maio, d_hsn, d_ma.size(), fn);
+      uint16_t arfcn = d_ma[mai];
+      double dsp_freq = static_cast<double>(gsm_arfcn2freq10(arfcn, 0)) * 1.0e5 - d_fc_rx;
+    }
+/*
+    void freq_hopper_msg_impl::add_hopping_cmd(pmt_t cmd) //TODO: fn and discard not supported at the moment
+    {
+      if(dict_ref(cmd,intern("cmd"), PMT_NIL) == intern("start")) {
+        if(dict_ref(cmd,intern("fn"), PMT_NIL)  != PMT_NIL){
+          //TODO add the command to the map<int,pmt_t>
+        } else {
+          pmt_t hopping_params = dict_ref(cmd, intern("hopping_params"), PMT_NIL);
+          d_hopping_enable = set_hopping_params(hopping_params);
+        } 
+      } else if(dict_ref(cmd,intern("cmd"), PMT_NIL) == intern("stop")) {
+        if(dict_ref(cmd,intern("fn"),PMT_NIL)  != PMT_NIL){
+          //TODO add the command to the map<int,pmt_t>
+          
+        } else {
+          d_hopping_enable = false;
+        }
+      }
+    }
+
+    void freq_hopper_msg_impl::set_freq_metadata(pmt_t burst)
+    {
+
+      if(d_hopping_enable) {
+        pmt_t pdu_header = car(burst);
+        pmt_t tx_time = dict_ref(pdu_header, intern("tx_time"),PMT_NIL);
+        if(tx_time != PMT_NIL){
+          pmt_t tx_command_time = cons(tuple_ref(tx_time,0),tuple_ref(tx_time,1));
+          pmt_t header_plus_burst = cdr(burst);
+          uint32_t frame_nr = 0;
+          
+          pmt_t fn = dict_ref(pdu_header,intern("fn"),PMT_NIL);
+          if(fn == PMT_NIL){
+            gsmtap_hdr *header = (gsmtap_hdr *)blob_data(header_plus_burst);
+            uint32_t frame_nr = be32toh(header->frame_number);
+          } else {
+            frame_nr = to_uint64(fn);
+          }
+          
+          int mai = calculate_ma_sfh(d_maio, d_hsn, d_ma.size(), frame_nr);
+          uint16_t arfcn = d_ma[mai];
+          
+  //        if(fn == PMT_NIL){
+  //          header->arfcn = htobe16(arfcn);
+  //          header->arfcn = header->arfcn | 0x8000; // set uplink flag
+  //        }
+          
+          //compute the frequences to be set in the burst header
+          double freq_uplink   = static_cast<double>(gsm_arfcn2freq10(arfcn, 1)) * 1.0e5;
+          double freq_downlink = static_cast<double>(gsm_arfcn2freq10(arfcn, 0)) * 1.0e5;
+          
+          pmt_t tx_command = dict_add(make_dict(),intern("lo_freq"),from_double(d_base_freq));
+          tx_command = dict_add(tx_command,intern("dsp_freq"),from_double(freq_uplink-d_base_freq));
+          tx_command = dict_add(tx_command,intern("time"),tx_command_time);
+
+          pmt_t rx_command = dict_add(make_dict(),intern("lo_freq"),from_double(d_base_freq));
+          rx_command = dict_add(rx_command,intern("dsp_freq"),from_double(freq_uplink-d_base_freq));
+          rx_command = dict_add(rx_command,intern("time"),tx_command_time);
+          rx_command = dict_add(rx_command,intern("direction"),intern("RX"));
+          
+          pdu_header = dict_add(pdu_header, intern("tx_command"),tx_command);
+//          pdu_header = dict_add(pdu_header, intern("tx_command"),rx_command);
+//          std::cout << "arfcn " << arfcn << " mai " << mai << " d_ma.size() " << d_ma.size() << " d_hsn " << d_hsn << std::endl;
+          std::cout << "arfcn_uplink " << arfcn << std::endl;
+//          std::cout << "freq_downlink " << freq_downlink << std::endl;
+//          std::cout << "pdu_header " << pdu_header << std::endl;
+//          std::cout << "size_header_plus_burst " << length(header_plus_burst) << std::endl;
+          message_port_pub(mp("bursts_out"), cons(pdu_header,header_plus_burst));
+        }
+      } else {
+        message_port_pub(mp("bursts_out"), burst);
+      }
+    }
+    
+    bool freq_hopper_msg_impl::set_hopping_params(pmt_t hopping_params){
+      bool retval = false;
+      if(hopping_params != PMT_NIL){
+        //set hopping parameters immediately
+        pmt_t hsn = dict_ref(hopping_params, intern("hsn"), PMT_NIL);
+        pmt_t maio = dict_ref(hopping_params, intern("maio"), PMT_NIL);;
+        pmt_t ma = dict_ref(hopping_params, intern("ma"), PMT_NIL);
+        
+        if(is_vector(ma) && is_integer(hsn) && is_integer(maio)){  //TODO: checking the values
+          d_hsn = to_uint64(hsn);
+          d_maio = to_uint64(maio);
+          d_ma.resize(length(ma));
+          for(int i=0; i<length(ma); i++){
+            d_ma[i] = to_uint64(vector_ref(ma,i));
+          }
+          retval = true;
+        }
+      }
+      return retval;
+    }*/
+
+  } /* namespace gsm */
+} /* namespace gr */
diff --git a/lib/trx/freq_hopper_msg_impl.h b/lib/trx/freq_hopper_msg_impl.h
new file mode 100644
index 0000000..2286012
--- /dev/null
+++ b/lib/trx/freq_hopper_msg_impl.h
@@ -0,0 +1,84 @@
+/* -*- c++ -*- */
+/* @file
+ * @author Piotr Krysik <ptrkrysik@gmail.com>
+ * @section LICENSE
+ * 
+ * Gr-gsm is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * Gr-gsm 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 General Public License
+ * along with gr-gsm; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ * 
+ */
+
+#ifndef INCLUDED_GSM_FREQ_HOPPER_MSG_IMPL_H
+#define INCLUDED_GSM_FREQ_HOPPER_MSG_IMPL_H
+
+#include <grgsm/trx/freq_hopper_msg.h>
+#include <grgsm/misc_utils/time_spec.h>
+#include <grgsm/misc_utils/fn_time.h>
+#include <pmt/pmt.h>
+
+
+namespace gr {
+  namespace gsm {
+
+    class freq_hopper_msg_impl : public freq_hopper_msg
+    {
+     private:
+      double d_samp_rate;
+      double d_fc_rx;
+      double d_fc_tx;
+      bool d_rx_hopping;
+      bool d_tx_hopping;
+      double d_freq_change_period;
+      bool d_rx_time_received;
+      time_spec_t d_last_rx_time;
+      time_spec_t d_current_time;
+      uint64_t d_current_start_offset; //!!zmienic nazwe - ta zmienna okresla pozycje ostatniego rx_time
+      uint64_t d_i;
+      std::vector<double> d_f;
+      double d_start_time;
+      time_spec_t d_next_change_time;
+      double d_change_advance;
+      pmt::pmt_t d_rx_time_key;
+
+//      bool d_hopping_enable; //if true block do the hopping, if not block just passes the bursts
+      uint64_t d_hsn; //hopping sequence number
+      uint64_t d_maio; //mobile allocation index offset
+      std::vector<uint64_t> d_ma; //mobile allocation
+
+      uint64_t d_current_fn;//!!
+
+//      pmt::pmt_t d_hopping_cmd; //TODO: change this a std::map
+//      void set_freq_metadata(pmt::pmt_t cmd);
+//      bool set_hopping_params(pmt::pmt_t hopping_params);
+      double get_dsp_freq(uint64_t fn);
+     public:
+      freq_hopper_msg_impl(
+        double samp_rate,
+        double start_fc_rx,
+        double start_fc_tx,
+        bool rx_hopping,
+        bool tx_hopping,
+        double freq_change_period);
+      ~freq_hopper_msg_impl();
+
+      int work(int noutput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items);
+
+//      void add_hopping_cmd(pmt::pmt_t hopping_cmd);
+    };
+
+  } // namespace gsm
+} // namespace gr
+
+#endif /* INCLUDED_GSM_FREQ_HOPPER_MSG_IMPL_H */
diff --git a/lib/trx/freq_hopping_impl.cc b/lib/trx/freq_hopper_tag_impl.cc
similarity index 89%
rename from lib/trx/freq_hopping_impl.cc
rename to lib/trx/freq_hopper_tag_impl.cc
index d6a2fb5..aeed88a 100644
--- a/lib/trx/freq_hopping_impl.cc
+++ b/lib/trx/freq_hopper_tag_impl.cc
@@ -1,4 +1,3 @@
-
 /* -*- c++ -*- */
 /* @file
  * @author Piotr Krysik <ptrkrysik@gmail.com>
@@ -28,7 +27,7 @@
 #include <gnuradio/io_signature.h>
 #include <grgsm/gsmtap.h>
 
-#include "freq_hopping_impl.h"
+#include "freq_hopper_tag_impl.h"
 #include "../misc_utils/freq_hopping_utils.h"
 extern "C" {
 #include <osmocom/gsm/gsm_utils.h>
@@ -38,20 +37,20 @@
   namespace gsm {
     using namespace pmt;
 
-    freq_hopping::sptr
-    freq_hopping::make(
+    freq_hopper_tag::sptr
+    freq_hopper_tag::make(
       pmt_t hopping_cmd)
     {
       return gnuradio::get_initial_sptr
-        (new freq_hopping_impl(hopping_cmd));
+        (new freq_hopper_tag_impl(hopping_cmd));
     }
 
     /*
      * The private constructor
      */
-    freq_hopping_impl::freq_hopping_impl(
+    freq_hopper_tag_impl::freq_hopper_tag_impl(
       pmt_t hopping_cmd
-    ) : gr::block("freq_hopping",
+    ) : gr::block("freq_hopper_tag",
           gr::io_signature::make(0, 0, 0),
           gr::io_signature::make(0, 0, 0)),
           d_hopping_cmd(PMT_NIL),
@@ -65,11 +64,11 @@
 
         // Bind message handlers
         set_msg_handler(mp("hopping_cmd"),
-          boost::bind(&freq_hopping_impl::add_hopping_cmd,
+          boost::bind(&freq_hopper_tag_impl::add_hopping_cmd,
             this, _1));
         
         set_msg_handler(mp("bursts_in"),
-          boost::bind(&freq_hopping_impl::set_freq_metadata,
+          boost::bind(&freq_hopper_tag_impl::set_freq_metadata,
             this, _1));
         
         add_hopping_cmd(hopping_cmd);
@@ -78,11 +77,11 @@
     /*
      * Our virtual destructor.
      */
-    freq_hopping_impl::~freq_hopping_impl()
+    freq_hopper_tag_impl::~freq_hopper_tag_impl()
     {
     }
     
-    void freq_hopping_impl::add_hopping_cmd(pmt_t cmd) //TODO: fn and discard not supported at the moment
+    void freq_hopper_tag_impl::add_hopping_cmd(pmt_t cmd) //TODO: fn and discard not supported at the moment
     {
       if(dict_ref(cmd,intern("cmd"), PMT_NIL) == intern("start")) {
         if(dict_ref(cmd,intern("fn"), PMT_NIL)  != PMT_NIL){
@@ -101,7 +100,7 @@
       }
     }
     
-    void freq_hopping_impl::set_freq_metadata(pmt_t burst)
+    void freq_hopper_tag_impl::set_freq_metadata(pmt_t burst)
     {
 
       if(d_hopping_enable) {
@@ -155,7 +154,7 @@
       }
     }
     
-    bool freq_hopping_impl::set_hopping_params(pmt_t hopping_params){
+    bool freq_hopper_tag_impl::set_hopping_params(pmt_t hopping_params){
       bool retval = false;
       if(hopping_params != PMT_NIL){
         //set hopping parameters immediately
diff --git a/lib/trx/freq_hopping_impl.h b/lib/trx/freq_hopper_tag_impl.h
similarity index 82%
rename from lib/trx/freq_hopping_impl.h
rename to lib/trx/freq_hopper_tag_impl.h
index b6c6366..d9da2e0 100644
--- a/lib/trx/freq_hopping_impl.h
+++ b/lib/trx/freq_hopper_tag_impl.h
@@ -20,17 +20,17 @@
  * 
  */
 
-#ifndef INCLUDED_GSM_FREQ_HOPPING_IMPL_H
-#define INCLUDED_GSM_FREQ_HOPPING_IMPL_H
+#ifndef INCLUDED_GSM_FREQ_HOPPER_TAG_IMPL_H
+#define INCLUDED_GSM_FREQ_HOPPER_TAG_IMPL_H
 
-#include <grgsm/trx/freq_hopping.h>
+#include <grgsm/trx/freq_hopper_tag.h>
 #include <grgsm/misc_utils/time_spec.h>
 #include <grgsm/misc_utils/fn_time.h>
 
 namespace gr {
   namespace gsm {
 
-    class freq_hopping_impl : public freq_hopping
+    class freq_hopper_tag_impl : public freq_hopper_tag
     {
      private:
       bool d_hopping_enable; //if true block do the hopping, if not block just passes the bursts
@@ -38,13 +38,13 @@
       uint64_t d_maio; //mobile allocation index offset
       double d_base_freq; //local oscillator frequency
       std::vector<uint64_t> d_ma; //mobile allocation
-     
+
       pmt::pmt_t d_hopping_cmd; //TODO: change this uint64_to a std::map
       void set_freq_metadata(pmt::pmt_t cmd);
       bool set_hopping_params(pmt::pmt_t hopping_params);
      public:
-      freq_hopping_impl(pmt::pmt_t hopping_cmd);
-      ~freq_hopping_impl();
+      freq_hopper_tag_impl(pmt::pmt_t hopping_cmd);
+      ~freq_hopper_tag_impl();
 
       void add_hopping_cmd(pmt::pmt_t hopping_cmd);
     };
@@ -52,4 +52,4 @@
   } // namespace gsm
 } // namespace gr
 
-#endif /* INCLUDED_GSM_FREQ_HOPPING_IMPL_H */
+#endif /* INCLUDED_GSM_FREQ_HOPPER_TAG_IMPL_H */
diff --git a/swig/grgsm_swig.i b/swig/grgsm_swig.i
index 8035dc5..d48e8ba 100644
--- a/swig/grgsm_swig.i
+++ b/swig/grgsm_swig.i
@@ -76,7 +76,8 @@
 #include "grgsm/transmitter/txtime_setter.h"
 #include "grgsm/transmitter/preprocess_tx_burst.h"
 #include "grgsm/transmitter/gen_test_ab.h"
-#include "grgsm/trx/freq_hopping.h"
+#include "grgsm/trx/freq_hopper_tag.h"
+#include "grgsm/trx/freq_hopper_msg.h"
 #include "grgsm/trx/trx_burst_if.h"
 %}
 
@@ -155,8 +156,10 @@
 GR_SWIG_BLOCK_MAGIC2(gsm, extract_cmc);
 %include "grgsm/misc_utils/extract_assignment_cmd.h"
 GR_SWIG_BLOCK_MAGIC2(gsm, extract_assignment_cmd);
-%include "grgsm/trx/freq_hopping.h"
-GR_SWIG_BLOCK_MAGIC2(gsm, freq_hopping);
+%include "grgsm/trx/freq_hopper_tag.h"
+GR_SWIG_BLOCK_MAGIC2(gsm, freq_hopper_tag);
+%include "grgsm/trx/freq_hopper_msg.h"
+GR_SWIG_BLOCK_MAGIC2(gsm, freq_hopper_msg);
 %include "grgsm/trx/trx_burst_if.h"
 GR_SWIG_BLOCK_MAGIC2(gsm, trx_burst_if);
 %include "grgsm/misc_utils/burst_to_fn_time.h"