[Commit-gnuradio] r3453 - gnuradio/trunk/gr-trellis/doc

[anastas]

Author: anastas
Date: 2006-08-30 15:59:48 -0600 (Wed, 30 Aug 2006)
New Revision: 3453

Modified:
   gnuradio/trunk/gr-trellis/doc/gr-trellis.xml
Log:
updated gr-trellis documentation

Modified: gnuradio/trunk/gr-trellis/doc/gr-trellis.xml
===================================================================
--- gnuradio/trunk/gr-trellis/doc/gr-trellis.xml        2006-08-30 18:33:26 UTC 
(rev 3452)
+++ gnuradio/trunk/gr-trellis/doc/gr-trellis.xml        2006-08-30 21:59:48 UTC 
(rev 3453)
@@ -178,12 +178,18 @@
   std::vector<int> d_OS;
   std::vector<int> d_PS;
   std::vector<int> d_PI;
+  std::vector<int> d_TMi;
+  std::vector<int> d_TMl;
+  void generate_PS_PI ();
+  void generate_TM ();
+  bool find_es(int es);
 public:
   fsm();
   fsm(const fsm &FSM);
-  fsm(const int I, const int S, const int O, const std::vector<int> 
&NS, const std::vector<int> &OS);
+  fsm(int I, int S, int O, const std::vector<int> &NS, const 
std::vector<int> &OS);
   fsm(const char *name);
-  fsm(const int mod_size, const int ch_length);
+  fsm(int k, int n, const std::vector<int> &G);
+  fsm(int mod_size, int ch_length);
   int I () const { return d_I; }
   int S () const { return d_S; }
   int O () const { return d_O; }
@@ -191,6 +197,8 @@
   const std::vector<int> & OS () const { return d_OS; }
   const std::vector<int> & PS () const { return d_PS; }
   const std::vector<int> & PI () const { return d_PI; }
+  const std::vector<int> & TMi () const { return d_TMi; }
+  const std::vector<int> & TMl () const { return d_TMl; }
 };
 </programlisting>
 
@@ -247,10 +255,26 @@
 </para>
 </listitem>
 
+
 <listitem>
-<para>The third way is specific to FSMs resulting from shift registers, and 
the output symbol being the entire transition (ie, current_state and 
current_input). These FSMs are usefull when describibg ISI channels. In 
particular the state is comprised of the.....
+<para>
+The third way is specific to FSMs representing binary (n,k) conolutional 
codes. These FSMs are specified by the number of input bits k, the number of 
output bits n, and the generator matrix, which is a k x n matrix of integers 
+G = [g<subscript>i,j</subscript>]<subscript>i=1:k, j=1:n</subscript>, given as 
an one-dimensional STL vector.
+Each integer g<subscript>i,j</subscript> is the decimal representation of the 
+polynomial g<subscript>i,j</subscript>(D) (e.g., g<subscript>i,j</subscript>= 
6 = 110<subscript>2</subscript> is interpreted as 
g<subscript>i,j</subscript>(D)=1+D) describing the connections from  the 
sequence x<subscript>i</subscript> to 
+y<subscript>j</subscript> (e.g., in the above example 
y<subscript>j</subscript>(k) = x<subscript>i</subscript>(k) + 
x<subscript>i</subscript>(k-1)).
 </para>
 <programlisting>
+  fsm(int k, int n, const std::vector&lt;int&gt; &amp;G);
+</programlisting>
+</listitem>
+
+
+<listitem>
+<para>
+The fourth way is specific to FSMs resulting from shift registers, and the 
output symbol being the entire transition (ie, current_state and 
current_input). These FSMs are usefull when describibg ISI channels. In 
particular the state is comprised of the input symbols x(k-1), 
x(k-2),...,x(k-L), where L = ch_length-1 and each x(i) belongs to an alphabet 
of size mod_size. The output is taken to be x(k), x(k-1), x(k-2),...,x(k-L) (in 
decimal format)
+</para>
+<programlisting>
   fsm(const int mod_size, const int ch_length);
 </programlisting>
 </listitem>
@@ -259,7 +283,7 @@
 
 
 <para>
-Finally, as can be seen from the above description, there are
+As can be seen from the above description, there are
 two more variables included in the FSM class implementation, 
 the PS and the PI matrices. These are computed internally 
 when an FSM is instantiated and their meaning is as follows.
@@ -289,12 +313,59 @@
 </para>
 
 
+<para>
+Finally, there are
+two more variables included in the FSM class implementation,
+the TMl and the TMi matrices. These are both S x S matrices (represented as 
STL vectors) computed internally
+when an FSM is instantiated and their meaning is as follows.
+TMl(i,j) is the minimum number of trellis steps required to go from state i to 
state j.
+Similarly, TMi(i,j) is the initial input required to get you from state i to 
state j in the minimum number of steps. As an example, if TMl(1,4)=2, it means 
that you need 2 steps in the trellis to get from state 1 to state 4. Further,
+if TMi(1,4)=0 it means that the first such step will be followed if when at 
state 1 the input is 0. Furthermore, suppose that NS(1,0)=2. Then, TMl(2,4) 
should be 1 (ie, one more step is needed when starting from state 2 and having 
state 4 as the final destination). Finally, TMi(2,4) will give us the second 
input required to complete the path from 1 to 4.
+These matrices are useful when we want to implement an encoder with proper 
state termination. For instance, based on these matrices we can evaluate how 
many 
+additional input symbols (and which particular inputs) are required to be 
appended at the end of an input sequence so that the final state is always 0.
+
+</para>
+
+
 </sect1>
 
 
 
+<!--=====================================================-->
+<sect1 id="blocks"><title>Blocks Using the FSM structure</title>
 
+<para>
+In this section we give a brief description of the basic blocks implemented 
that make use of the previously described FSM structure.
+</para>
 
+
+<!-- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -->
+<sect2 id="encoder"><title>Trellis Encoder</title>
+
+<para>
+The trellis.encoder_XX(FSM, ST) block instantiates an FSM encoder 
corresponding to the fsm FSM and having initial state ST. The input and output 
is a sequence of bytes, shorts or integers. 
+</para>
+
+</sect2>
+
+<!-- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -->
+<sect2 id="decoder"><title>Viterbi Decoder</title>
+
+<para>
+The trellis.viterbi_X(FSM, K, S0, SK) block instantiates a Viterbi decoder
+for an underlying ...
+</para>
+
+</sect2>
+
+
+
+
+
+
+</sect1>
+
+
 <!--=====================================================-->
 <sect1 id="tcm"><title>TCM: A Complete Example</title>
 
@@ -514,8 +585,8 @@
 
 <listitem>
 <para>
-automate fsm generation from generator polynomials 
-(feedforward or feedback form).
+automate fsm generation from rational functions
+(feedback form).
 </para>
 </listitem>
 
@@ -527,8 +598,7 @@
 
 <listitem>
 <para>
-Provide implementation of soft-input soft-output (SISO) decoders for 
-potential use in concatenated systems. Also a host of suboptimal
+A host of suboptimal
 decoders, eg, sphere decoding, M- and T- algorithms, sequential decoding, etc.
 can be implemented.
 </para>
@@ -542,6 +612,7 @@
 use the encoder, and SISO blocks and connect them
 through GNU radio or we should implement turbo-decoding
 as a single block (issues with buffering between blocks).
+So far the former has been implemented.
 </para>
 </listitem>