diff --git a/lib/flow_control/burst_sdcch_subslot_filter_impl.cc b/lib/flow_control/burst_sdcch_subslot_filter_impl.cc
new file mode 100644
index 0000000..9f27fcd
--- /dev/null
+++ b/lib/flow_control/burst_sdcch_subslot_filter_impl.cc
@@ -0,0 +1,95 @@
+/* -*- c++ -*- */
+/* @file
+ * @author Roman Khassraf <rkhassraf@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 "burst_sdcch_subslot_filter_impl.h"
+#include <stdio.h>
+#include <grgsm/endian.h>
+#include <grgsm/gsmtap.h>
+
+
+namespace gr {
+  namespace gsm {
+
+    burst_sdcch_subslot_filter::sptr
+    burst_sdcch_subslot_filter::make(subslot_filter_mode mode, unsigned int subslot)
+    {
+      return gnuradio::get_initial_sptr
+        (new burst_sdcch_subslot_filter_impl(mode, subslot));
+    }
+
+    /*
+     * The private constructor
+     */
+    burst_sdcch_subslot_filter_impl::burst_sdcch_subslot_filter_impl(subslot_filter_mode mode, unsigned int subslot)
+      : gr::block("burst_sdcch_subslot_filter",
+              gr::io_signature::make(0, 0, 0),
+              gr::io_signature::make(0, 0, 0)),
+      d_mode(mode),
+      d_subslot(subslot)
+    {     
+        message_port_register_in(pmt::mp("in"));
+        message_port_register_out(pmt::mp("out"));
+        
+        set_msg_handler(pmt::mp("in"), boost::bind(&burst_sdcch_subslot_filter_impl::process_burst, this, _1));
+    }
+
+    /*
+     * Our virtual destructor.
+     */
+    burst_sdcch_subslot_filter_impl::~burst_sdcch_subslot_filter_impl() {}
+
+    void burst_sdcch_subslot_filter_impl::process_burst(pmt::pmt_t msg)
+    {
+        pmt::pmt_t header_plus_burst = pmt::cdr(msg);
+        gsmtap_hdr * header = (gsmtap_hdr *)pmt::blob_data(header_plus_burst);
+        
+        uint32_t frame_nr = be32toh(header->frame_number);
+        uint32_t fn_mod102 = frame_nr % 102;
+        
+        int8_t subslot;
+        
+        if (d_mode == SS_FILTER_SDCCH8)
+        {
+            subslot = d_subslots_sdcch8[fn_mod102];
+        }
+        else if (d_mode == SS_FILTER_SDCCH4)
+        {
+            subslot = d_subslots_sdcch4[fn_mod102];
+        }
+        
+        if ((subslot == -1) || (d_mode == SS_FILTER_SDCCH4 && subslot > 3))
+        {
+            return;
+        }
+        
+        if (subslot == d_subslot)
+        {
+            message_port_pub(pmt::mp("out"), msg);
+        }
+    }
+  } /* namespace gsm */
+} /* namespace gr */
diff --git a/lib/flow_control/burst_sdcch_subslot_filter_impl.h b/lib/flow_control/burst_sdcch_subslot_filter_impl.h
new file mode 100644
index 0000000..05038d7
--- /dev/null
+++ b/lib/flow_control/burst_sdcch_subslot_filter_impl.h
@@ -0,0 +1,55 @@
+/* -*- c++ -*- */
+/* @file
+ * @author Roman Khassraf <rkhassraf@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_BURST_SDCCH_SUBSLOT_FILTER_IMPL_H
+#define INCLUDED_GSM_BURST_SDCCH_SUBSLOT_FILTER_IMPL_H
+
+#include <grgsm/flow_control/burst_sdcch_subslot_filter.h>
+
+namespace gr {
+  namespace gsm {
+
+    class burst_sdcch_subslot_filter_impl : public burst_sdcch_subslot_filter
+    {
+     private:
+      // hardcoded subslots of the channels, both SDCCH and the associated SACCH
+      // -1 means that the particular position in the frame is not SDCCH
+      const int8_t d_subslots_sdcch4[102] = {
+          -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, 0, 0, 0, 0, 1, 1, 1, 1,-1,-1, 2, 2, 2, 2, 3, 3, 3, 3,-1,-1, 0, 0, 0, 0, 1, 1, 1, 1,-1,
+          -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, 0, 0, 0, 0, 1, 1, 1, 1,-1,-1, 2, 2, 2, 2, 3, 3, 3, 3,-1,-1, 2, 2, 2, 2, 3, 3, 3, 3,-1
+      };
+      const int8_t d_subslots_sdcch8[102] = {
+          0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3,-1,-1,-1,
+          0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7,-1,-1,-1
+      };
+      subslot_filter_mode d_mode;
+      unsigned int d_subslot;
+     public:
+      burst_sdcch_subslot_filter_impl(subslot_filter_mode mode, unsigned int subslot);
+      ~burst_sdcch_subslot_filter_impl();
+      void process_burst(pmt::pmt_t msg);
+    };
+
+  } // namespace gsm
+} // namespace gr
+
+#endif /* INCLUDED_GSM_BURST_SDCCH_SUBSLOT_FILTER_IMPL_H */