MIMO Channel Estimation

gr-digital/CMakeLists.txt

@@ -52,6 +52,17 @@ SET(GR_PKG_DIGITAL_EXAMPLES_DIR ${GR_PKG_DATA_DIR}/examples/digital)
 ########################################################################
 if(ENABLE_GR_DIGITAL)
 
+########################################################################
+# Find package Eigen3 (for optional MIMO features)
+########################################################################
+find_package(Eigen3)
+add_definitions(-DEIGEN3_ENABLED=${Eigen3_FOUND})
+if(Eigen3_FOUND)
+    message([STATUS] "Eigen3 found.")
+else()
+    message([STATUS] "Eigen3 not found. Eigen3 is required for MxM MIMO schemes with M>2.")
+endif(Eigen3_FOUND)
+
 ########################################################################
 # Setup CPack components
 ########################################################################

gr-digital/grc/digital_mimo_channel_estimator_cc.xml

@@ -0,0 +1,32 @@
+<block>
+  <name>MIMO Channel estimator</name>
+  <key>digital_mimo_channel_estimator_cc</key>
+  <category>[MIMO]</category>
+  <import>from gnuraido import digital</import>
+  <make>digital.mimo_channel_estimator_cc($M, $N, $training_sequence)</make>
+  <param>
+    <name>M</name>
+    <key>M</key>
+    <type>int</type>
+  </param>
+  <param>
+    <name>N</name>
+    <key>N</key>
+    <type>int</type>
+  </param>
+  <param>
+    <name>Training Sequence</name>
+    <key>training_sequence</key>
+    <type>raw</type>
+  </param>
+  <sink>
+    <name>in</name>
+    <type>complex</type>
+    <nports>N</nports>
+  </sink>
+  <source>
+    <name>out</name>
+    <type>complex</type>
+    <nports>N</nports>
+  </source>
+</block>

gr-digital/grc/digital_vblast_decoder_cc.xml

@@ -0,0 +1,36 @@
+<block>
+  <name>V-BLAST Decoder</name>
+  <key>digital_vblast_decoder_cc</key>
+  <category>[MIMO]</category>
+  <import>from gnuradio import digital</import>
+  <make>digital.vblast_decoder_cc($num_inputs, $equalizer_type)</make>
+  <param>
+    <name>Number of Inputs</name>
+    <key>num_inputs</key>
+    <value>2</value>
+    <type>int</type>
+  </param>
+  <param>
+    <name>Equalizer Type</name>
+    <key>equalizer_type</key>
+    <value>"ZF"</value>
+    <type>string</type>
+    <option>
+      <name>Zero Forcing</name>
+      <key>"ZF"</key>
+    </option>
+    <option>
+      <name>Minimum Mean Squared Error</name>
+      <key>"MMSE"</key>
+    </option>
+  </param>
+  <sink>
+    <name>in</name>
+    <type>complex</type>
+    <nports>$num_inputs</nports>
+  </sink>
+  <source>
+    <name>out</name>
+    <type>complex</type>
+  </source>
+</block>

gr-digital/grc/digital_vblast_encoder_cc.xml

@@ -0,0 +1,22 @@
+<block>
+  <name>V-BLAST Encoder</name>
+  <key>digital_vblast_encoder_cc</key>
+  <category>[MIMO]</category>
+  <import>from gnuradio import digital</import>
+  <make>digital.vblast_encoder_cc($num_outputs)</make>
+  <param>
+    <name>Number of Outputs</name>
+    <key>num_outputs</key>
+    <value>2</value>
+    <type>int</type>
+  </param>
+  <sink>
+    <name>in</name>
+    <type>complex</type>
+  </sink>
+  <source>
+    <name>out</name>
+    <type>complex</type>
+    <nports>$num_outputs</nports>
+  </source>
+</block>

gr-digital/include/gnuradio/digital/CMakeLists.txt

@@ -121,6 +121,9 @@ install(FILES
     header_payload_demux.h
     alamouti_encoder_cc.h
     alamouti_decoder_cc.h
-    diversity_combiner_cc.h DESTINATION ${GR_INCLUDE_DIR}/gnuradio/digital
+    diversity_combiner_cc.h
+    vblast_encoder_cc.h
+    vblast_decoder_cc.h
+    mimo_channel_estimator_cc.h DESTINATION ${GR_INCLUDE_DIR}/gnuradio/digital
     COMPONENT "digital_devel"
 )

gr-digital/include/gnuradio/digital/mimo_channel_estimator_cc.h

@@ -0,0 +1,73 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2018 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio 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.
+ * 
+ * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#ifndef INCLUDED_DIGITAL_MIMO_CHANNEL_ESTIMATOR_CC_H
+#define INCLUDED_DIGITAL_MIMO_CHANNEL_ESTIMATOR_CC_H
+
+#include <gnuradio/digital/api.h>
+#include <gnuradio/block.h>
+
+namespace gr {
+  namespace digital {
+
+    /*! \brief Estimates a MIMO channel matrix.
+     *
+     * The block estimates the channel matrix of a MIMO scheme with the help of
+     * training sequences. The training sequence for each transmitting antenna
+     * equals one subvector/row of the 2-dimensional vector training_sequence.
+     * The training sequence should be appended as a pilot to the data at the transmitter.
+     * The beginning of the pilot must be tagged at the receiver with the key 'pilot'.
+     * This tag can be set from a preceding sync block, for example.
+     *
+     * This block has N inports and N outports. It estimates the channel matrix which each incoming
+     * 'pilot' tag, dumps the pilot symbol of each stream and passes the rest of the data through without
+     * changing anything. A tag is set at the beginning of each symbol (= a data sequence between to training sequences)
+     * with the key 'csi' that contains the estimated MxN channel matrix.
+     *
+     * For 1xN and 2xN MIMO schemes, the equalizer is calculated internally. For MxN schemes with M > 2,
+     * the C++ template library Eigen is used for the linear algebra operations
+     * and is a requirement in this case.
+     * The training_length is not bounded above, but the minimum length is M
+     * (to avoid an underdetermined equation system).
+     */
+    class DIGITAL_API mimo_channel_estimator_cc : virtual public gr::block
+    {
+     public:
+      typedef boost::shared_ptr<mimo_channel_estimator_cc> sptr;
+
+      /*!
+       * \brief Return a shared_ptr to a new instance of digital::mimo_channel_estimator_cc.
+       *
+       * To avoid accidental use of raw pointers, digital::mimo_channel_estimator_cc's
+       * constructor is in a private implementation
+       * class. digital::mimo_channel_estimator_cc::make is the public interface for
+       * creating new instances.
+       */
+      static sptr make(uint16_t M, uint16_t N, std::vector<std::vector<gr_complex> > training_sequence);
+    };
+
+  } // namespace digital
+} // namespace gr
+
+#endif /* INCLUDED_DIGITAL_MIMO_CHANNEL_ESTIMATOR_CC_H */
+

gr-digital/include/gnuradio/digital/vblast_decoder_cc.h

@@ -0,0 +1,68 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2018 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio 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.
+ * 
+ * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#ifndef INCLUDED_DIGITAL_VBLAST_DECODER_CC_H
+#define INCLUDED_DIGITAL_VBLAST_DECODER_CC_H
+
+#include <gnuradio/digital/api.h>
+#include <gnuradio/sync_interpolator.h>
+
+namespace gr {
+  namespace digital {
+
+/*! \brief VBLAST decoder.
+ * Decodes incoming MxM MIMO data by equalizing the received signals in order to extract the
+ * M different transmission signals. For the equalization, you can choose between a
+ * zero forcing (key='ZF') and a minimum mean squared error (key='MMSE') scheme. Both schemes require
+ * channel state information and MMSE additionally needs SNR information.
+ *
+ * The CSI and SNR information is transported via stream tags with key='csi' or 'snr', respectively.
+ * Initially the CSI is set to 1.0 + 0j for both branches and are updated
+ * with each incoming CSI. The SNR is initially set to 1.0e6; in this case is the MMSE equalizer equal
+ * to the ZF equalizer. The CSI and SNR tags are processed separately and they can therefore arrive
+ * at different positions of the stream and occur in different frequencies.
+ *
+ * For 1x1 and 2x2 MIMO schemes, the equalizer is calculated internally. For MxM schemes with M > 2,
+ * the C++ template library Eigen is used for the linear algebra operations.
+ */
+    class DIGITAL_API vblast_decoder_cc : virtual public gr::sync_interpolator
+    {
+     public:
+      typedef boost::shared_ptr<vblast_decoder_cc> sptr;
+
+      /*!
+       * \brief Return a shared_ptr to a new instance of digital::vblast_decoder_cc.
+       *
+       * To avoid accidental use of raw pointers, digital::vblast_decoder_cc's
+       * constructor is in a private implementation
+       * class. digital::vblast_decoder_cc::make is the public interface for
+       * creating new instances.
+       */
+      static sptr make(uint16_t num_inputs, std::string equalizer_type);
+    };
+
+  } // namespace digital
+} // namespace gr
+
+#endif /* INCLUDED_DIGITAL_VBLAST_DECODER_CC_H */
+

gr-digital/include/gnuradio/digital/vblast_encoder_cc.h

@@ -0,0 +1,58 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2018 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio 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.
+ * 
+ * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#ifndef INCLUDED_DIGITAL_VBLAST_ENCODER_CC_H
+#define INCLUDED_DIGITAL_VBLAST_ENCODER_CC_H
+
+#include <gnuradio/digital/api.h>
+#include <gnuradio/sync_decimator.h>
+
+namespace gr {
+  namespace digital {
+
+/*! \brief VBLAST encoder.
+ * Encodes a serial input data stream into a vertical transmission vector
+ * which is transmitted at once over multiple antennas.
+ * The functionality equals a multiplexing of the data.
+ */
+    class DIGITAL_API vblast_encoder_cc : virtual public gr::sync_decimator
+    {
+     public:
+      typedef boost::shared_ptr<vblast_encoder_cc> sptr;
+
+      /*!
+       * \brief Return a shared_ptr to a new instance of digital::vblast_encoder_cc.
+       *
+       * To avoid accidental use of raw pointers, digital::vblast_encoder_cc's
+       * constructor is in a private implementation
+       * class. digital::vblast_encoder_cc::make is the public interface for
+       * creating new instances.
+       */
+      static sptr make(uint16_t num_outputs);
+    };
+
+  } // namespace digital
+} // namespace gr
+
+#endif /* INCLUDED_DIGITAL_VBLAST_ENCODER_CC_H */
+

gr-digital/lib/CMakeLists.txt

@@ -135,6 +135,9 @@ list(APPEND digital_sources
     alamouti_encoder_cc_impl.cc
     alamouti_decoder_cc_impl.cc
     diversity_combiner_cc_impl.cc
+    vblast_encoder_cc_impl.cc
+    vblast_decoder_cc_impl.cc
+    mimo_channel_estimator_cc_impl.cc
 )
 
 #Add Windows DLL resource file if using MSVC