From 54d6b9281dc233e0b2acf26884073d973b7663de Mon Sep 17 00:00:00 2001
From: jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5>
Date: Tue, 4 Sep 2007 02:43:56 +0000
Subject: Merged r6271:6278 from jcorgan/t182 into trunk. Implements
ticket:182.
Created new top-level component, gr-utils, to hold commonly used utility
scripts (originally in gnuradio-examples). These now install into the
system path, allowing their use from wherever.
Reorganization of gnuradio-examples component:
* Commonly used utility scripts moved from python/usrp into gr-utils.
* Examples now install into $(prefix)/share/gnuradio/examples/...
* Channel coding examples moved into gr-trellis/src/examples, now install
from there, only if gr-atsc itself is going to built and installed.
* ATSC example scripts now install into example hierarchy
* Cruft has been moved into 'limbo' in repository, do not get installed
Trunk passes 'make distcheck'.
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@6279 221aa14e-8319-0410-a670-987f0aec2ac5
---
.../src/examples/test_viterbi_equalization.py | 94 ++++++++++++++++++++++
1 file changed, 94 insertions(+)
create mode 100755 gr-trellis/src/examples/test_viterbi_equalization.py
(limited to 'gr-trellis/src/examples/test_viterbi_equalization.py')
diff --git a/gr-trellis/src/examples/test_viterbi_equalization.py b/gr-trellis/src/examples/test_viterbi_equalization.py
new file mode 100755
index 0000000000..24545e3b0d
--- /dev/null
+++ b/gr-trellis/src/examples/test_viterbi_equalization.py
@@ -0,0 +1,94 @@
+#!/usr/bin/env python
+
+from gnuradio import gr
+from gnuradio import audio
+from gnuradio import trellis
+from gnuradio import eng_notation
+import math
+import sys
+import fsm_utils
+
+def run_test (f,Kb,bitspersymbol,K,dimensionality,tot_constellation,N0,seed):
+ fg = gr.flow_graph ()
+
+ # TX
+ src = gr.lfsr_32k_source_s()
+ src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts
+ s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality
+ enc = trellis.encoder_ss(f,0) # initial state = 0
+ # essentially here we implement the combination of modulation and channel as a memoryless modulation (the memory induced by the channel is hidden in the FSM)
+ mod = gr.chunks_to_symbols_sf(tot_constellation,dimensionality)
+
+ # CHANNEL
+ add = gr.add_ff()
+ noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)
+
+ # RX
+ metrics = trellis.metrics_f(f.O(),dimensionality,tot_constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi
+ va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set.
+ fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
+ dst = gr.check_lfsr_32k_s();
+
+ fg.connect (src,src_head,s2fsmi,enc,mod)
+ fg.connect (mod,(add,0))
+ fg.connect (noise,(add,1))
+ fg.connect (add,metrics)
+ fg.connect (metrics,va,fsmi2s,dst)
+
+ fg.run()
+
+ ntotal = dst.ntotal ()
+ nright = dst.nright ()
+ runlength = dst.runlength ()
+ #print ntotal,nright,runlength
+
+ return (ntotal,ntotal-nright)
+
+
+
+
+def main(args):
+ nargs = len (args)
+ if nargs == 2:
+ esn0_db=float(args[0])
+ rep=int(args[1])
+ else:
+ sys.stderr.write ('usage: test_viterbi_equalization.py Es/No_db repetitions\n')
+ sys.exit (1)
+
+ # system parameters
+ Kb=128*16 # packet size in bits (multiple of 16)
+ modulation = fsm_utils.pam4 # see fsm_utlis.py for available predefined modulations
+ channel = fsm_utils.c_channel # see fsm_utlis.py for available predefined test channels
+ f=trellis.fsm(len(modulation[1]),len(channel)) # generate the FSM automatically
+ bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol
+ K=Kb/bitspersymbol # packet size in trellis steps
+
+ tot_channel = fsm_utils.make_isi_lookup(modulation,channel,True) # generate the lookup table (normalize energy to 1)
+ dimensionality = tot_channel[0]
+ tot_constellation = tot_channel[1]
+ N0=pow(10.0,-esn0_db/10.0); # noise variance
+ if len(tot_constellation)/dimensionality != f.O():
+ sys.stderr.write ('Incompatible FSM output cardinality and lookup table size.\n')
+ sys.exit (1)
+
+
+ tot_s=0 # total number of transmitted shorts
+ terr_s=0 # total number of shorts in error
+ terr_p=0 # total number of packets in error
+
+ for i in range(rep):
+ (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,tot_constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations
+ tot_s=tot_s+s
+ terr_s=terr_s+e
+ terr_p=terr_p+(terr_s!=0)
+ if ((i+1)%100==0) : # display progress
+ print i+1,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
+ # estimate of the (short or bit) error rate
+ print rep,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
+
+
+
+if __name__ == '__main__':
+ main (sys.argv[1:])
+
--
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