Mostly minor editing. I think it's mostly done now, except for Section 7.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6368 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/ftrsd/ftrsd_paper/ftrsd.lyx

@@ -117,7 +117,7 @@ A major reason for the success and popularity of JT65 is its use of a strong
  error-correction code: a short block-length, low-rate Reed-Solomon code
  based on a 64-symbol alphabet.
  Until now, nearly all programs implementing JT65 have used the patented
- Koetter-Vardy (KV) algebraic soft-decision decoder 
+ Kötter-Vardy (KV) algebraic soft-decision decoder 
 \begin_inset CommandInset citation
 LatexCommand cite
 key "kv2001"
@@ -155,9 +155,8 @@ The JT65 protocol specifies transmissions that normally start one second
  into a UTC minute and last for 46.8 seconds.
  Receiving software therefore has up to several seconds to decode a message
  before the start of the next minute, when the operator sends a reply.
- With today's personal computers, this relatively long time available for
+ With today's personal computers, this relatively long available time encourages
- decoding a short message encourages experimentation with decoders of high
+ experimentation with decoders of high computational complexity.
- computational complexity.
  As a result, on a typical fading channel the FT algorithm can extend the
  decoding threshold by many dB over the hard-decision Berlekamp-Massey decoder,
  and by a meaningful amount over the KV decoder.
@@ -247,7 +246,7 @@ The minimum Hamming distance of the JT65 code is
 \end_inset
 
 , which means that any particular codeword differs from all other codewords
- in at least 52 symbol positions.
+ in at least 52 or the 63 symbol positions.
  
 \end_layout
 
@@ -1326,10 +1325,10 @@ If
 \end_inset
 
  and 
-\begin_inset Formula $X_{1}=X.$
+\begin_inset Formula $X_{1}=X,$
 \end_inset
 
-
+ and save the codeword.
 \end_layout
 
 \begin_layout Enumerate
@@ -1375,7 +1374,7 @@ Otherwise, declare decoding failure and exit.
 
 \begin_layout Enumerate
 An acceptable codeword has been found.
- Declare a successful decode and return this codeword.
+ Declare a successful decode and return the saved codeword.
 \end_layout
 
 \end_inset
@@ -1416,7 +1415,7 @@ stochastic erasures-only list decoding algorithm
 \begin_inset Quotes erd
 \end_inset
 
-, described in reference 
+ described in reference 
 \begin_inset CommandInset citation
 LatexCommand cite
 key "ls2009"
@@ -1462,14 +1461,14 @@ much
 \emph default
  smaller list of messages (say, a few thousand messages or less) that we
  might suppose would be among the most likely ones to be received.
- One such situation exists when making short ham-radio contacts that exchange
+ One such favorable situation exists when making short ham-radio contacts
- minimal information including callsigns, signal reports, perhaps Maidenhead
+ that exchange minimal information including callsigns, signal reports,
- locators, and acknowledgments.
+ perhaps Maidenhead locators, and acknowledgments.
  On the EME path or a VHF or UHF band with limited geographical coverage,
  the most common received messages often originate from callsigns that have
  been decoded before.
  Saving a list of previously decoded callsigns and associated locators makes
- it easy to generate lists of hypothetical messages and their corresponding
+ it easy to generate a list of hypothetical messages and their corresponding
  codewords at very little computational expense.
  The resulting candidate codewords can be tested in almost the same way
  as those generated by the probabilistic method described in Section 
@@ -1507,7 +1506,12 @@ For hinted decoding we again invoke a ratio threshold test, but in this
  case we use it to answer a more limited question.
  Over the full list of messages considered likely, we want to know whether
  a suitable metric can distinguish with confidence between the one correct
- codeword and all others in the generated list.
+ codeword and all others in the generated list --- or, alternatively, to
+ determine that the correct codeword is 
+\emph on
+not
+\emph default
+ contained in the list.
  We again find that the most effective metric involves a comparison of 
 \begin_inset Formula $u_{1}$
 \end_inset
@@ -1521,12 +1525,12 @@ For hinted decoding we again invoke a ratio threshold test, but in this
  The criterion for comparison is chosen empirically to maximize the number
  of correct decodes while ensuring that false decodes are rare.
  Because tested candidate codewords are drawn from a list typically no longer
- than a few thousand, rather than 
+ than a few thousand entries, rather than 
 \begin_inset Formula $2^{72},$
 \end_inset
 
  the limit can can be more relaxed than that used in the FT algorithm.
- THus, for the limited subset of messages suggested by operator experience
+ Thus, for the limited subset of messages suggested by previous experience
  to be likely, hinted decodes can be obtained at lower signal levels than
  required for the full universe of 
 \begin_inset Formula $2^{72}$
@@ -1535,6 +1539,18 @@ For hinted decoding we again invoke a ratio threshold test, but in this
  possible messages.
 \end_layout
 
+\begin_layout Standard
+Pseudo-code for the hinted decode or 
+\begin_inset Quotes eld
+\end_inset
+
+Deep Search
+\begin_inset Quotes erd
+\end_inset
+
+ algorithm is presented in an accompanying text box.
+\end_layout
+
 \begin_layout Standard
 \begin_inset Float algorithm
 wide false
@@ -1584,14 +1600,14 @@ If
 \end_inset
 
  by setting 
-\begin_inset Formula $u_{2}=u_{1},$
+\begin_inset Formula $u_{2}=u_{1}.$
 \end_inset
 
- then set 
+ Then set 
-\begin_inset Formula $u_{1}=u.$
+\begin_inset Formula $u_{1}=u$
 \end_inset
 
-
+ and save the codeword.
 \end_layout
 
 \begin_layout Enumerate
@@ -1611,12 +1627,22 @@ If
 \end_layout
 
 \begin_layout Enumerate
-Otherwise, declare hinted-decoding failure and exit.
+Otherwise, declare decoding failure and exit.
 \end_layout
 
 \begin_layout Enumerate
 An acceptable hinted decode has been found.
- Declare a successful result and return this codeword.
+ Declare a successful result and return the saved codeword and the value
+ 
+\begin_inset Formula $q=100*(u_{1}-bu_{2})$
+\end_inset
+
+ as a confidence indicator.
+ By default we use 
+\begin_inset Formula $b=1.12$
+\end_inset
+
+.
 \end_layout
 
 \end_inset
@@ -1667,7 +1693,7 @@ reference "sec:Appendix:SNR"
 .
  Examples of both types of plot are included in the following discussion,
  where we describe simulations carried out to compare performance of FT
- with other algorithms and with theoretical expectations.
+ and hinted decoding with other algorithms and with theoretical expectations.
  We have also used simulations to establish suitable default values for
  the acceptance parameters 
 \begin_inset Formula $X_{0},$
@@ -1723,11 +1749,11 @@ reference "fig:bodide"
 
 \end_inset
 
- also shows results calculated from theory for comparison with the BM results.
+ also shows results calculated from theoretical probability distributions
+ for comparison with the BM results.
  The simulated BM results agree with theory to within about 0.1 dB.
- This difference between simulated BM results and theory is caused by small
+ This differences are caused by small errors in the estimates of time and
- errors in the estimates of time- and frequency-offset of the received signal
+ frequency offset of the received signal in the simulated data.
- in the simulated data.
  Such 
 \begin_inset Quotes eld
 \end_inset
@@ -1741,7 +1767,7 @@ sync losses
 \end_layout
 
 \begin_layout Standard
-As expected, the soft-decision algorithms, FT and KV, are about 2 dB better
+As expected, the soft-decision algorithms FT and KV are about 2 dB better
  than the hard-decision BM algorithm.
  In addition, FT has an edge over KV that increases from 
 \begin_inset Formula $\sim0.2$
@@ -1928,7 +1954,11 @@ name "fig:WER2"
 
 \end_inset
 
-Percent of JT65 messages copied as a function of SNR in 2500 Hz bandwidth.
+Percent of JT65 messages copied as a function of 
+\begin_inset Formula $\mathrm{SNR}{}_{2500},$
+\end_inset
+
+ assuming additive white gaussian noise and no fading.
  Numbers adjacent to curves specify values of timeout parameter 
 \begin_inset Formula $T$
 \end_inset
@@ -1976,11 +2006,11 @@ reference "fig:N_vs_X"
 
  the number of hard-decision errors in the received word.
  This run used 1000 simulated transmissions at 
-\begin_inset Formula $\mathrm{SNR}=-24$
+\begin_inset Formula $\mathrm{SNR_{2500}}=-24$
 \end_inset
 
- dB, just slightly above the decoding threshold, and the timeout parameter
+ dB, just slightly above the decoding threshold, with timeout parameter
- was 
+ 
 \begin_inset Formula $T=10^{5}.$
 \end_inset
 
@@ -2004,8 +2034,8 @@ reference "fig:N_vs_X"
  symbol errors.
  The results also show that, on average, the number of trials increases
  with the number of errors in the received word.
- The variability of the decoding time also increases dramatically with the
+ The variability of decoding time also increases dramatically with the number
- number of errors in the received word.
+ of errors in the received word.
  These results provide insight into the mean and variance of the execution
  time for the FT algorithm, since execution time is roughly proportional
  to the number of required trials.
@@ -2044,9 +2074,8 @@ Number of trials needed to decode a received word versus Hamming distance
 \end_inset
 
  between the received word and the decoded codeword, for 1000 simulated
- frames on an AWGN channel with no fading.
+ transmissions on an AWGN channel with no fading and
- The SNR in 2500 Hz bandwidth is 
+\begin_inset Formula $\mathrm{SNR}{}_{2500}=-24$
-\begin_inset Formula $-24$
 \end_inset
 
  dB, which corresponds to 
@@ -2101,18 +2130,21 @@ reference "fig:Psuccess"
 \begin_layout Standard
 It is interesting to note that while Rayleigh fading severely degrades the
  success rate of the BM decoder, the penalties are much smaller with both
- FT and hinted decoding.
+ FT and 
+\begin_inset Quotes eld
+\end_inset
+
+Deep Search
+\begin_inset Quotes erd
+\end_inset
+
+ decoding.
  Simulated Doppler spreads of 0.2 Hz actually increased the FT and DS decoding
  rates slightly at SNRs close to the decoding threshold, presumably because
  with the low-rate JT65 code signal peaks can be enough to produce good
  copy.
 \end_layout
 
-\begin_layout Standard
-(*** New data will be used for the DS curves.
- ***)
-\end_layout
-
 \begin_layout Standard
 \begin_inset Float figure
 wide false
@@ -2140,11 +2172,14 @@ name "fig:Psuccess"
 
 \end_inset
 
-Percentage of JT65 messages successfully decoded as a function of SNR in
+Percentage of JT65 messages successfully decoded as a function of 
- 2500 Hz bandwidth.
+\begin_inset Formula $\mathrm{SNR}{}_{2500}$
+\end_inset
+
+.
  Results are shown for the hard-decision Berlekamp-Massey (BM) and soft-decision
  Franke-Taylor (FT) decoding algorithms.
- Curves labeled DS correspond to the hinted-decode (
+ Curves labeled DS correspond to the hinted-decode or 
 \begin_inset Quotes eld
 \end_inset
 
@@ -2152,8 +2187,8 @@ Deep Search
 \begin_inset Quotes erd
 \end_inset
 
-) algorithm.
+ algorithm.
- Numbers adjacent to the curves are the simulated Doppler spreads in Hz.
+ Numbers adjacent to the curves are simulated Doppler spreads in Hz.
  The curve labeled 
 \begin_inset Quotes eld
 \end_inset
@@ -2162,8 +2197,8 @@ Sync
 \begin_inset Quotes erd
 \end_inset
 
- illustrates the rate of correct time and frequency synchronization in the
+ illustrates the success rate of correct time and frequency synchronization
- decoder presently implemented in program 
+ in the decoder presently implemented in program 
 \emph on
 WSJT-X
 \emph default
@@ -2247,7 +2282,7 @@ key "kv2001"
 \end_inset
 
 “Algebraic soft-decision decoding of Reed-Solomon codes,” R.
- Köetter and A.
+ Kötter and A.
  Vardy, 
 \emph on
 IEEE Transactions on Information Theory
@@ -2276,6 +2311,22 @@ WSJT Home Page
 \begin_inset CommandInset bibitem
 LatexCommand bibitem
 label "3"
+key "lc2004"
+
+\end_inset
+
+
+\emph on
+Error Control Coding, 2nd Edition
+\emph default
+, Shu Lin and Daniel J.
+ Costello, Pearson-Prentice Hall, 2004.
+\end_layout
+
+\begin_layout Bibliography
+\begin_inset CommandInset bibitem
+LatexCommand bibitem
+label "4"
 key "lhmg2010"
 
 \end_inset
@@ -2294,7 +2345,7 @@ IEEE Communications Letters
 \begin_layout Bibliography
 \begin_inset CommandInset bibitem
 LatexCommand bibitem
-label "4"
+label "5"
 key "lk2008"
 
 \end_inset
@@ -2313,25 +2364,7 @@ GLOBECOM
 \begin_inset Quotes erd
 \end_inset
 
- 2008 proceedings
+ 2008 proceedings.
-\emph default
-.
-\end_layout
-
-\begin_layout Bibliography
-\begin_inset CommandInset bibitem
-LatexCommand bibitem
-label "5"
-key "lc2004"
-
-\end_inset
-
-
-\emph on
-Error Control Coding, 2nd Edition
-\emph default
-, Shu Lin and Daniel J.
- Costello, Pearson-Prentice Hall, 2004.
 \end_layout
 
 \begin_layout Bibliography