diff options
| -rw-r--r-- | gr-trellis/doc/gr-trellis.xml | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/gr-trellis/doc/gr-trellis.xml b/gr-trellis/doc/gr-trellis.xml index 4f117ec38..5f1921343 100644 --- a/gr-trellis/doc/gr-trellis.xml +++ b/gr-trellis/doc/gr-trellis.xml @@ -822,7 +822,7 @@ The modulated symbols are filtered by the ISI channel and AWGN with appropriate <para> Since the output alphabet of the equivalent FSM is quite large (1024) we chose to utilize the combined metrics calculator and Viterbi algorithm block. -also note that the first L observations are irrelevant and tus can be skipped. +Also note that the first L observations are irrelevant and thus can be skipped. </para> <programlisting> 33 # RX @@ -873,7 +873,17 @@ The function returns the number of symbols and the number of symbols in error. O <para> Soft versions of the algorithms have been implemented. -Also examples of turbo equalization/decoding and of sccc can be found in the examples directory. +Also examples of turbo equalization/decoding and of sccc can +be found in the examples directory. + +Recently we added gnuradio blocks for sccc and pccc encoders and +turbo decoders. +Although these can be generated by existing gr-trellis blocks (in particular, +the SISO blocks, as done in some of the python examples) there is an advantage +in having this functionality as a single block. To see why, think of a turbo decoder with 10 iterations. Previously we needed to concatenate 10 x 2 SISO blocks +(for a sccc decoder) to emulate the passing of soft information between SISOs over 10 iterartions. With the new block however, only a single such block is needed that internally loops through 10 iterations; this results in space savings +and possibly time saving as well (since queueing at the input/ouput of the gr-blocks is avoided). + Still need to document them... </para> |