Trellis-based algorithms for GNU Radio

Achilleas Anastasopoulos

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Trellis-based algorithms for GNU Radio

Achilleas Anastasopoulos

<anastas@umich.edu>

Revision History
Revision v0.0	2006-08-03
First cut. @@ -47,9 +47,9 @@ in how the outside world interprets these input and output integer symbols. Here is an example of an FSM describing the (2,1) CC with constraint length 3 and generator polynomial matrix -(1+D+D² 1+D²) +(1+D+D² , 1+D²) from Proakis-Salehi pg. 779. - Example 1. (2,1) CC with generator polynomials (1+D+D² 1+D²) + Example 1. (2,1) CC with generator polynomials (1+D+D² , 1+D²) This CC accepts 1 bit at a time, and outputs 2 bits at a time. It has a shift register storing the last two input bits. In particular, @@ -77,7 +77,7 @@ s_k x_k s_k+1 The "output-symbol" function OS(,) can be given by -s_k x_k y_k +s_k x_k y_k 0 0 0 0 1 3 1 0 3 @@ -131,7 +131,9 @@ ways to construct an FSM. fsm(const int I, const int S, const int O, const std::vector<int> &NS, const std::vector<int> &OS); Giving a filename containing all the FSM information: fsm(const char name); - This information has to be in the following format + +This information has to be in the following format: + I S O NS(0,0) NS(0,1) ... NS(0,I-1) @@ -143,7 +145,10 @@ OS(0,0) OS(0,1) ... OS(0,I-1) OS(1,0) OS(1,1) ... OS(1,I-1) ... OS(S-1,0) OS(S-1,1) ... OS(S-1,I-1) - For instance, the file containing the information for the example mentioned above is of the form + + +For instance, the file containing the information for the example mentioned above is of the form: + 2 4 4 0 2 @@ -155,7 +160,8 @@ OS(S-1,0) OS(S-1,1) ... OS(S-1,I-1) 3 0 1 2 2 1 - 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..... + + 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..... fsm(const int mod_size, const int ch_length); @@ -198,112 +204,103 @@ an additive white Gaussian noise (AWGN) channel, and the VA performing MLSD. The program source is as follows. -#!/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 random -import fsm_utils - -def run_test (f,Kb,bitspersymbol,K,dimensionality,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 - mod = gr.chunks_to_symbols_sf(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,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() - - # A bit of cheating: run the program once and print the - # final encoder state.. - # Then put it as the last argument in the viterbi block - #print "final state = " , enc.ST() - - ntotal = dst.ntotal () - nright = dst.nright () - runlength = dst.runlength () - return (ntotal,ntotal-nright) - - - - -def main(args): - nargs = len (args) - if nargs == 3: - fname=args[0] - esn0_db=float(args[1]) # Es/No in dB - rep=int(args[2]) # number of times the experiment is run to collect enough errors - else: - sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db repetitions\n') - sys.exit (1) - - # system parameters - f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) - Kb=102416 # packet size in bits (make it multiple of 16 so it can be packed in a short) - bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol - K=Kb/bitspersymbol # packet size in trellis steps - modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations - dimensionality = modulation[0] - constellation = modulation[1] - if len(constellation)/dimensionality != f.O(): - sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') - sys.exit (1) - # calculate average symbol energy - Es = 0 - for i in range(len(constellation)): - Es = Es + constellation[i]*2 - Es = Es / (len(constellation)/dimensionality) - N0=Es/pow(10.0,esn0_db/10.0); # noise variance - - - - tot_s=0 - terr_s=0 - for i in range(rep): - (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,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 - if (i%100==0): - print i,s,e,tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) - # estimate of the (short) error rate - print tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) - - -if __name__ == '__main__': - main (sys.argv[1:]) + 1 #!/usr/bin/env python + 2 + 3 from gnuradio import gr + 4 from gnuradio import audio + 5 from gnuradio import trellis + 6 from gnuradio import eng_notation + 7 import math + 8 import sys + 9 import random + 10 import fsm_utils + 11 + 12 def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed): + 13 fg = gr.flow_graph () + 14 + 15 # TX + 16 src = gr.lfsr_32k_source_s() + 17 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts + 18 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality + 19 enc = trellis.encoder_ss(f,0) # initial state = 0 + 20 mod = gr.chunks_to_symbols_sf(constellation,dimensionality) + 21 + 22 # CHANNEL + 23 add = gr.add_ff() + 24 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) + 25 + 26 # RX + 27 metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi + 28 va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set. + 29 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts + 30 dst = gr.check_lfsr_32k_s(); + 31 + 32 fg.connect (src,src_head,s2fsmi,enc,mod) + 33 fg.connect (mod,(add,0)) + 34 fg.connect (noise,(add,1)) + 35 fg.connect (add,metrics) + 36 fg.connect (metrics,va,fsmi2s,dst) + 37 + 38 fg.run() + 39 + 40 # A bit of cheating: run the program once and print the + 41 # final encoder state. + 42 # Then put it as the last argument in the viterbi block + 43 #print "final state = " , enc.ST() + 44 + 45 ntotal = dst.ntotal () + 46 nright = dst.nright () + 47 runlength = dst.runlength () + 48 return (ntotal,ntotal-nright) + 49 + 50 + 51 def main(args): + 52 nargs = len (args) + 53 if nargs == 3: + 54 fname=args[0] + 55 esn0_db=float(args[1]) # Es/No in dB + 56 rep=int(args[2]) # number of times the experiment is run to collect enough errors + 57 else: + 58 sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db repetitions\n') + 59 sys.exit (1) + 60 + 61 # system parameters + 62 f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) + 63 Kb=102416 # packet size in bits (make it multiple of 16 so it can be packed in a short) + 64 bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol + 65 K=Kb/bitspersymbol # packet size in trellis steps + 66 modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations + 67 dimensionality = modulation[0] + 68 constellation = modulation[1] + 69 if len(constellation)/dimensionality != f.O(): + 70 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') + 71 sys.exit (1) + 72 # calculate average symbol energy + 73 Es = 0 + 74 for i in range(len(constellation)): + 75 Es = Es + constellation[i]*2 + 76 Es = Es / (len(constellation)/dimensionality) + 77 N0=Es/pow(10.0,esn0_db/10.0); # noise variance + 78 + 79 tot_s=0 + 80 terr_s=0 + 81 for i in range(rep): + 82 (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations + 83 tot_s=tot_s+s + 84 terr_s=terr_s+e + 85 if (i%100==0): + 86 print i,s,e,tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) + 87 # estimate of the (short) error rate + 88 print tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) + 89 + 90 + 91 if __name__ == '__main__': + 92 main (sys.argv[1:]) The program is called by - -./test_tcm.py fsm_fname Es/No_db repetitions - + +./test_tcm.py fsm_fname Es/No_db repetitions + where "fsm_fname" is the file containing the FSM specification of the tested TCM code, "Es/No_db" is the SNR in dB, and "repetitions" are the number of packets to be transmitted and received in order to @@ -312,7 +309,7 @@ error rate. The FSM is first intantiated in "main" by - f=trellis.fsm(fname) + 62 f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) Each packet has size Kb bits (we choose Kb to be a multiple of 16 so that all bits fit nicely into shorts and can be generated by the lfsr GNU Radio). @@ -321,9 +318,9 @@ of bitspersymbol=log₂( I ). The Kb/16 shorts are now unpacked to K=Kb/bitspersymbol input symbols that will drive the FSM encoder. - Kb=102416 # packet size in bits (make it multiple of 16 so it can be packed in a short) - bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol - K=Kb/bitspersymbol # packet size in trellis steps + 63 Kb=102416 # packet size in bits (make it multiple of 16 so it can be packed in a short) + 64 bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol + 65 K=Kb/bitspersymbol # packet size in trellis steps The FSM will produce K output symbols (remeber the FSM produces always one output symbol for each input symbol). Each of these symbols needs to be modulated. Since we are simulating the communication system, we need not simulate the actual waveforms. An M-ary, N-dimensional modulation is completely specified by a set of M, N-dimensional real vectors. In "fsm_utils.py" file we give a number of useful modulations with the following format: modulation = (N,constellation), where @@ -336,23 +333,23 @@ For instance, 4-ary PAM is represented as Clearly, M should be equal to the cardinality of the FSM output, O. Finally the average symbol energy and noise variance are calculated. - modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations - dimensionality = modulation[0] - constellation = modulation[1] - if len(constellation)/dimensionality != f.O(): - sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') - sys.exit (1) - # calculate average symbol energy - Es = 0 - for i in range(len(constellation)): - Es = Es + constellation[i]2 - Es = Es / (len(constellation)/dimensionality) - N0=Es/pow(10.0,esn0_db/10.0); # noise variance + 66 modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations + 67 dimensionality = modulation[0] + 68 constellation = modulation[1] + 69 if len(constellation)/dimensionality != f.O(): + 70 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') + 71 sys.exit (1) + 72 # calculate average symbol energy + 73 Es = 0 + 74 for i in range(len(constellation)): + 75 Es = Es + constellation[i]2 + 76 Es = Es / (len(constellation)/dimensionality) + 77 N0=Es/pow(10.0,esn0_db/10.0); # noise variance Then, "run_test" is called with a different "seed" so that we get different noise realizations. - (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations + 82 (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations Let us examine now the "run_test" function. First we set up the transmitter blocks. @@ -361,25 +358,27 @@ symbols consistent with the FSM input alphabet. The FSm encoder requires the FSM specification, and an initial state (which is set to 0 in this example). - # 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 + 15 # TX + 16 src = gr.lfsr_32k_source_s() + 17 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts + 18 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality + 19 enc = trellis.encoder_ss(f,0) # initial state = 0 +We now need to modulate the FSM output symbols. The "chunks_to_symbols_sf" is essentially a memoryless mapper which for each input symbol y_k outputs a sequence of N numbers ci1,ci2,...,ciN representing the coordianates of the constellation symbol c_i with i=y_k. - mod = gr.chunks_to_symbols_sf(constellation,dimensionality) + 20 mod = gr.chunks_to_symbols_sf(constellation,dimensionality) The channel is AWGN with appropriate noise variance. For each transmitted symbol c_k=(ck1,ck2,...,ckN) we receive a noisy version r_k=(rk1,rk2,...,rkN). - add = gr.add_ff() - noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) + 22 # CHANNEL + 23 add = gr.add_ff() + 24 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) Part of the design methodology was to decouple the FSM and VA from the details of the modulation, channel, receiver front-end etc. @@ -408,8 +407,8 @@ do hard decision demodulation and feed the VA with symbol Hamming distances, or even bit Hamming distances, etc. These are all implemented in "metrics_f". - # RX - metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi + 26 # RX + 27 metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi Now the VA can run once it is supplied by the initial and final states. The initial state is known to be 0; the final state is usually @@ -418,14 +417,14 @@ In this example, we always send the the same info sequence (we only randomize no or final state). The VA outputs the estimates of the symbols x_k which are then packed to shorts and compared with the transmitted sequence. - 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(); + 28 va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set. + 29 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts + 30 dst = gr.check_lfsr_32k_s(); The function returns the number of shorts and the number of shorts in error. Observe that this way the estimated error rate refers to 16-bit-symbol error rate. -return (ntotal,ntotal-nright) + 48 return (ntotal,ntotal-nright) Future Work Improve the documentation :-) @@ -437,10 +436,11 @@ Optimize the VA code. Provide implementation of soft-input soft-output (SISO) decoders for potential use in concatenated systems. Also a host of suboptimal decoders, eg, sphere decoding, M- and T- algorithms, sequential decoding, etc. +can be implemented. Although turbo decoding is rediculously slow in software, -we can design it in pronciple. The question is, should -we use the FSM and SISO abstractions and cnnect them -through GNU radio or should we implement turbo-decoding +we can design it in principle. One question is, whether we should +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). diff --git a/gr-trellis/doc/gr-trellis.xml b/gr-trellis/doc/gr-trellis.xml index f34ba78e3..dd4e4c81d 100644 --- a/gr-trellis/doc/gr-trellis.xml +++ b/gr-trellis/doc/gr-trellis.xml @@ -1,7 +1,7 @@ + ]> @@ -311,110 +311,13 @@ the VA performing MLSD. The program source is as follows. - - - -#!/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 random -import fsm_utils - -def run_test (f,Kb,bitspersymbol,K,dimensionality,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 - mod = gr.chunks_to_symbols_sf(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,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() - - # A bit of cheating: run the program once and print the - # final encoder state.. - # Then put it as the last argument in the viterbi block - #print "final state = " , enc.ST() - - ntotal = dst.ntotal () - nright = dst.nright () - runlength = dst.runlength () - return (ntotal,ntotal-nright) - - -def main(args): - nargs = len (args) - if nargs == 3: - fname=args[0] - esn0_db=float(args[1]) # Es/No in dB - rep=int(args[2]) # number of times the experiment is run to collect enough errors - else: - sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db repetitions\n') - sys.exit (1) - - # system parameters - f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) - Kb=102416 # packet size in bits (make it multiple of 16 so it can be packed in a short) - bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol - K=Kb/bitspersymbol # packet size in trellis steps - modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations - dimensionality = modulation[0] - constellation = modulation[1] - if len(constellation)/dimensionality != f.O(): - sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') - sys.exit (1) - # calculate average symbol energy - Es = 0 - for i in range(len(constellation)): - Es = Es + constellation[i]*2 - Es = Es / (len(constellation)/dimensionality) - N0=Es/pow(10.0,esn0_db/10.0); # noise variance - - tot_s=0 - terr_s=0 - for i in range(rep): - (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,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 - if (i%100==0): - print i,s,e,tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) - # estimate of the (short) error rate - print tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) - - -if __name__ == '__main__': - main (sys.argv[1:]) - +&test_tcm_listing; The program is called by - - + ./test_tcm.py fsm_fname Es/No_db repetitions - - + where "fsm_fname" is the file containing the FSM specification of the tested TCM code, "Es/No_db" is the SNR in dB, and "repetitions" are the number of packets to be transmitted and received in order to @@ -426,7 +329,7 @@ error rate. The FSM is first intantiated in "main" by - f=trellis.fsm(fname) + 62 f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) @@ -444,9 +347,9 @@ unpacked to K=Kb/bitspersymbol input symbols that will drive the FSM encoder. - Kb=102416 # packet size in bits (make it multiple of 16 so it can be packed in a short) - bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol - K=Kb/bitspersymbol # packet size in trellis steps + 63 Kb=102416 # packet size in bits (make it multiple of 16 so it can be packed in a short) + 64 bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol + 65 K=Kb/bitspersymbol # packet size in trellis steps @@ -464,18 +367,18 @@ Clearly, M should be equal to the cardinality of the FSM output, O. Finally the average symbol energy and noise variance are calculated. - modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations - dimensionality = modulation[0] - constellation = modulation[1] - if len(constellation)/dimensionality != f.O(): - sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') - sys.exit (1) - # calculate average symbol energy - Es = 0 - for i in range(len(constellation)): - Es = Es + constellation[i]2 - Es = Es / (len(constellation)/dimensionality) - N0=Es/pow(10.0,esn0_db/10.0); # noise variance + 66 modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations + 67 dimensionality = modulation[0] + 68 constellation = modulation[1] + 69 if len(constellation)/dimensionality != f.O(): + 70 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') + 71 sys.exit (1) + 72 # calculate average symbol energy + 73 Es = 0 + 74 for i in range(len(constellation)): + 75 Es = Es + constellation[i]2 + 76 Es = Es / (len(constellation)/dimensionality) + 77 N0=Es/pow(10.0,esn0_db/10.0); # noise variance @@ -485,7 +388,7 @@ Then, "run_test" is called with a different "seed" so that we get different noise realizations. - (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations + 82 (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations @@ -499,25 +402,25 @@ The FSm encoder requires the FSM specification, and an initial state (which is set to 0 in this example). - # 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 + 15 # TX + 16 src = gr.lfsr_32k_source_s() + 17 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts + 18 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality + 19 enc = trellis.encoder_ss(f,0) # initial state = 0 - +We now need to modulate the FSM output symbols. The "chunks_to_symbols_sf" is essentially a memoryless mapper which for each input symbol y_k outputs a sequence of N numbers ci1,ci2,...,ciN representing the coordianates of the constellation symbol c_i with i=y_k. - mod = gr.chunks_to_symbols_sf(constellation,dimensionality) + 20 mod = gr.chunks_to_symbols_sf(constellation,dimensionality) @@ -526,9 +429,9 @@ For each transmitted symbol c_k=(ck1,ck2,...,ckN) we receive a noisy version r_k=(rk1,rk2,...,rkN). - # CHANNEL - add = gr.add_ff() - noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) + 22 # CHANNEL + 23 add = gr.add_ff() + 24 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) @@ -562,8 +465,8 @@ symbol Hamming distances, or even bit Hamming distances, etc. These are all implemented in "metrics_f". - # RX - metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi + 26 # RX + 27 metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi @@ -575,9 +478,9 @@ or final state). The VA outputs the estimates of the symbols x_k which are then packed to shorts and compared with the transmitted sequence. - 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(); + 28 va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set. + 29 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts + 30 dst = gr.check_lfsr_32k_s(); @@ -588,7 +491,7 @@ The function returns the number of shorts and the number of shorts in error. Obs 16-bit-symbol error rate. - return (ntotal,ntotal-nright) + 48 return (ntotal,ntotal-nright) @@ -596,7 +499,7 @@ The function returns the number of shorts and the number of shorts in error. Obs - + Future Work @@ -637,7 +540,7 @@ can be implemented. Although turbo decoding is rediculously slow in software, we can design it in principle. One question is, whether we should use the encoder, and SISO blocks and connect them -through GNU radio or should we implement turbo-decoding +through GNU radio or we should implement turbo-decoding as a single block (issues with buffering between blocks). diff --git a/gr-trellis/doc/make_numbered_listing.py b/gr-trellis/doc/make_numbered_listing.py new file mode 100755 index 000000000..889c2d78d --- /dev/null +++ b/gr-trellis/doc/make_numbered_listing.py @@ -0,0 +1,45 @@ +#!/usr/bin/env python + +import sys +import os, os.path +from optparse import OptionParser + +def quote_line (line): + line = line.replace ('&', '&') + line = line.replace ('<', '<') + line = line.replace ('>', '>') + line = line.replace ("'", ''') + line = line.replace ('"', '"') + return line + +def generate_listing (input_filename, title=None): + inf = open (input_filename, "r") + output_filename = os.path.basename (input_filename) + '.xml' + outf = open (output_filename, "w") + outf.write ('\n') + # outf.write ('\n' % (input_filename,)) + # if not title: + # title = input_filename + # outf.write ('') + # outf.write (title) + # outf.write ('\n') + outf.write ('\n'); + + lineno = 0 + for line in inf: + line = line.expandtabs (8) + line = quote_line (line) + lineno = lineno + 1 + outf.write ('%3d %s' % (lineno, line)) + + outf.write ('\n') + # outf.write ('\n') + + +def main (): + for file in sys.argv[1:]: + generate_listing (file) + +if __name__ == '__main__': + main () + diff --git a/gr-trellis/doc/test_tcm.py b/gr-trellis/doc/test_tcm.py index 02d1e6c5c..bf93a421f 100644 --- a/gr-trellis/doc/test_tcm.py +++ b/gr-trellis/doc/test_tcm.py @@ -12,67 +12,42 @@ import fsm_utils def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed): fg = gr.flow_graph () - # TX - #packet = [0]Kb - #for i in range(Kb-116): # last 16 bits = 0 to drive the final state to 0 - #packet[i] = random.randint(0, 1) # random 0s and 1s - #src = gr.vector_source_s(packet,False) src = gr.lfsr_32k_source_s() src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts - #b2s = gr.unpacked_to_packed_ss(1,gr.GR_MSB_FIRST) # pack bits 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 mod = gr.chunks_to_symbols_sf(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,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 - #s2b = gr.packed_to_unpacked_ss(1,gr.GR_MSB_FIRST) # unpack shorts to bits - #dst = gr.vector_sink_s(); dst = gr.check_lfsr_32k_s(); - fg.connect (src,src_head,s2fsmi,enc,mod) - #fg.connect (src,b2s,s2fsmi,enc,mod) fg.connect (mod,(add,0)) fg.connect (noise,(add,1)) fg.connect (add,metrics) fg.connect (metrics,va,fsmi2s,dst) - #fg.connect (metrics,va,fsmi2s,s2b,dst) - fg.run() # A bit of cheating: run the program once and print the - # final encoder state.. + # final encoder state. # Then put it as the last argument in the viterbi block #print "final state = " , enc.ST() ntotal = dst.ntotal () nright = dst.nright () runlength = dst.runlength () - #ntotal = len(packet) - #if len(dst.data()) != ntotal: - #print "Error: not enough data\n" - #nright = 0; - #for i in range(ntotal): - #if packet[i]==dst.data()[i]: - #nright=nright+1 - #else: - #print "Error in ", i return (ntotal,ntotal-nright) - - def main(args): nargs = len (args) if nargs == 3: @@ -101,8 +76,6 @@ def main(args): Es = Es / (len(constellation)/dimensionality) N0=Es/pow(10.0,esn0_db/10.0); # noise variance - - tot_s=0 terr_s=0 for i in range(rep): @@ -111,10 +84,9 @@ def main(args): terr_s=terr_s+e if (i%100==0): print i,s,e,tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) - # estimate of the (short or bit) error rate + # estimate of the (short) error rate print tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) if __name__ == '__main__': main (sys.argv[1:]) - diff --git a/gr-trellis/doc/test_tcm.py.xml b/gr-trellis/doc/test_tcm.py.xml new file mode 100644 index 000000000..ff15f4476 --- /dev/null +++ b/gr-trellis/doc/test_tcm.py.xml @@ -0,0 +1,95 @@ + + + 1 #!/usr/bin/env python + 2 + 3 from gnuradio import gr + 4 from gnuradio import audio + 5 from gnuradio import trellis + 6 from gnuradio import eng_notation + 7 import math + 8 import sys + 9 import random + 10 import fsm_utils + 11 + 12 def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed): + 13 fg = gr.flow_graph () + 14 + 15 # TX + 16 src = gr.lfsr_32k_source_s() + 17 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts + 18 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality + 19 enc = trellis.encoder_ss(f,0) # initial state = 0 + 20 mod = gr.chunks_to_symbols_sf(constellation,dimensionality) + 21 + 22 # CHANNEL + 23 add = gr.add_ff() + 24 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) + 25 + 26 # RX + 27 metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi + 28 va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set. + 29 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts + 30 dst = gr.check_lfsr_32k_s(); + 31 + 32 fg.connect (src,src_head,s2fsmi,enc,mod) + 33 fg.connect (mod,(add,0)) + 34 fg.connect (noise,(add,1)) + 35 fg.connect (add,metrics) + 36 fg.connect (metrics,va,fsmi2s,dst) + 37 + 38 fg.run() + 39 + 40 # A bit of cheating: run the program once and print the + 41 # final encoder state. + 42 # Then put it as the last argument in the viterbi block + 43 #print "final state = " , enc.ST() + 44 + 45 ntotal = dst.ntotal () + 46 nright = dst.nright () + 47 runlength = dst.runlength () + 48 return (ntotal,ntotal-nright) + 49 + 50 + 51 def main(args): + 52 nargs = len (args) + 53 if nargs == 3: + 54 fname=args[0] + 55 esn0_db=float(args[1]) # Es/No in dB + 56 rep=int(args[2]) # number of times the experiment is run to collect enough errors + 57 else: + 58 sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db repetitions\n') + 59 sys.exit (1) + 60 + 61 # system parameters + 62 f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) + 63 Kb=102416 # packet size in bits (make it multiple of 16 so it can be packed in a short) + 64 bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol + 65 K=Kb/bitspersymbol # packet size in trellis steps + 66 modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations + 67 dimensionality = modulation[0] + 68 constellation = modulation[1] + 69 if len(constellation)/dimensionality != f.O(): + 70 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') + 71 sys.exit (1) + 72 # calculate average symbol energy + 73 Es = 0 + 74 for i in range(len(constellation)): + 75 Es = Es + constellation[i]*2 + 76 Es = Es / (len(constellation)/dimensionality) + 77 N0=Es/pow(10.0,esn0_db/10.0); # noise variance + 78 + 79 tot_s=0 + 80 terr_s=0 + 81 for i in range(rep): + 82 (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations + 83 tot_s=tot_s+s + 84 terr_s=terr_s+e + 85 if (i%100==0): + 86 print i,s,e,tot_s,terr_s, '%e' % ((1.0terr_s)/tot_s) + 87 # estimate of the (short) error rate + 88 print tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s) + 89 + 90 + 91 if __name__ == '__main__': + 92 main (sys.argv[1:]) + -- cgit

Revision History

Revision v0.0

2006-08-03

First cut. @@ -47,9 +47,9 @@ in how the outside world interprets these input and output integer symbols. Here is an example of an FSM describing the (2,1) CC with constraint length 3 and generator polynomial matrix -(1+D+D² 1+D²) +(1+D+D² , 1+D²) from Proakis-Salehi pg. 779. -

Example 1. (2,1) CC with generator polynomials (1+D+D² 1+D²)

Example 1. (2,1) CC with generator polynomials (1+D+D² , 1+D²)

This CC accepts 1 bit at a time, and outputs 2 bits at a time. It has a shift register storing the last two input bits. In particular, @@ -77,7 +77,7 @@ s_k x_k s_k+1

The "output-symbol" function OS(,) can be given by

-s_k       x_k       y_k
+s_k	x_k	y_k
 0	0	0
 0	1	3
 1	0	3
@@ -131,7 +131,9 @@ ways to construct an FSM.
   fsm(const int I, const int S, const int O, const std::vector<int> &NS, const std::vector<int> &OS);

Giving a filename containing all the FSM information:

   fsm(const char *name);
-

This information has to be in the following format

+This information has to be in the following format: +

 I S O
 
 NS(0,0)   NS(0,1)   ...  NS(0,I-1)
@@ -143,7 +145,10 @@ OS(0,0)   OS(0,1)   ...  OS(0,I-1)
 OS(1,0)   OS(1,1)   ...  OS(1,I-1)
 ...
 OS(S-1,0) OS(S-1,1) ... OS(S-1,I-1)
-

For instance, the file containing the information for the example mentioned above is of the form

+For instance, the file containing the information for the example mentioned above is of the form: +

 2 4 4
 
 0 2
@@ -155,7 +160,8 @@ OS(S-1,0) OS(S-1,1) ... OS(S-1,I-1)
 3 0
 1 2
 2 1
-

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..... +

   fsm(const int mod_size, const int ch_length);

@@ -198,112 +204,103 @@ an additive white Gaussian noise (AWGN) channel, and the VA performing MLSD. The program source is as follows.

-#!/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 random
-import fsm_utils
-
-def run_test (f,Kb,bitspersymbol,K,dimensionality,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
-    mod = gr.chunks_to_symbols_sf(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,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()
-    
-    # A bit of cheating: run the program once and print the 
-    # final encoder state..
-    # Then put it as the last argument in the viterbi block
-    #print "final state = " , enc.ST()
-
-    ntotal = dst.ntotal ()
-    nright = dst.nright ()
-    runlength = dst.runlength ()
-    return (ntotal,ntotal-nright)
-
-
-
-
-def main(args):
-    nargs = len (args)
-    if nargs == 3:
-        fname=args[0]
-        esn0_db=float(args[1]) # Es/No in dB
-        rep=int(args[2]) # number of times the experiment is run to collect enough errors
-    else:
-        sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db  repetitions\n')
-        sys.exit (1)
-
-    # system parameters
-    f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...)
-    Kb=1024*16  # packet size in bits (make it multiple of 16 so it can be packed in a short)
-    bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol
-    K=Kb/bitspersymbol # packet size in trellis steps
-    modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations
-    dimensionality = modulation[0]
-    constellation = modulation[1] 
-    if len(constellation)/dimensionality != f.O():
-        sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n')
-        sys.exit (1)
-    # calculate average symbol energy
-    Es = 0
-    for i in range(len(constellation)):
-        Es = Es + constellation[i]**2
-    Es = Es / (len(constellation)/dimensionality)
-    N0=Es/pow(10.0,esn0_db/10.0); # noise variance
-    
-
-
-    tot_s=0
-    terr_s=0
-    for i in range(rep):
-        (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,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
-        if (i%100==0):
-            print i,s,e,tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s)
-    # estimate of the (short) error rate
-    print tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s)
-
-
-if __name__ == '__main__':
-    main (sys.argv[1:])
+  1  #!/usr/bin/env python
+  2  
+  3  from gnuradio import gr
+  4  from gnuradio import audio
+  5  from gnuradio import trellis
+  6  from gnuradio import eng_notation
+  7  import math
+  8  import sys
+  9  import random
+ 10  import fsm_utils
+ 11  
+ 12  def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed):
+ 13      fg = gr.flow_graph ()
+ 14  
+ 15      # TX
+ 16      src = gr.lfsr_32k_source_s()
+ 17      src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts
+ 18      s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality
+ 19      enc = trellis.encoder_ss(f,0) # initial state = 0
+ 20      mod = gr.chunks_to_symbols_sf(constellation,dimensionality)
+ 21  
+ 22      # CHANNEL
+ 23      add = gr.add_ff()
+ 24      noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)
+ 25  
+ 26      # RX
+ 27      metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi
+ 28      va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set.
+ 29      fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
+ 30      dst = gr.check_lfsr_32k_s(); 
+ 31  
+ 32      fg.connect (src,src_head,s2fsmi,enc,mod)
+ 33      fg.connect (mod,(add,0))
+ 34      fg.connect (noise,(add,1))
+ 35      fg.connect (add,metrics)
+ 36      fg.connect (metrics,va,fsmi2s,dst)
+ 37      
+ 38      fg.run()
+ 39      
+ 40      # A bit of cheating: run the program once and print the 
+ 41      # final encoder state.
+ 42      # Then put it as the last argument in the viterbi block
+ 43      #print "final state = " , enc.ST()
+ 44  
+ 45      ntotal = dst.ntotal ()
+ 46      nright = dst.nright ()
+ 47      runlength = dst.runlength ()
+ 48      return (ntotal,ntotal-nright)
+ 49  
+ 50  
+ 51  def main(args):
+ 52      nargs = len (args)
+ 53      if nargs == 3:
+ 54          fname=args[0]
+ 55          esn0_db=float(args[1]) # Es/No in dB
+ 56          rep=int(args[2]) # number of times the experiment is run to collect enough errors
+ 57      else:
+ 58          sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db  repetitions\n')
+ 59          sys.exit (1)
+ 60  
+ 61      # system parameters
+ 62      f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...)
+ 63      Kb=1024*16  # packet size in bits (make it multiple of 16 so it can be packed in a short)
+ 64      bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol
+ 65      K=Kb/bitspersymbol # packet size in trellis steps
+ 66      modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations
+ 67      dimensionality = modulation[0]
+ 68      constellation = modulation[1] 
+ 69      if len(constellation)/dimensionality != f.O():
+ 70          sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n')
+ 71          sys.exit (1)
+ 72      # calculate average symbol energy
+ 73      Es = 0
+ 74      for i in range(len(constellation)):
+ 75          Es = Es + constellation[i]**2
+ 76      Es = Es / (len(constellation)/dimensionality)
+ 77      N0=Es/pow(10.0,esn0_db/10.0); # noise variance
+ 78      
+ 79      tot_s=0
+ 80      terr_s=0
+ 81      for i in range(rep):
+ 82          (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations
+ 83          tot_s=tot_s+s
+ 84          terr_s=terr_s+e
+ 85          if (i%100==0):
+ 86              print i,s,e,tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s)
+ 87      # estimate of the (short) error rate
+ 88      print tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s)
+ 89  
+ 90  
+ 91  if __name__ == '__main__':
+ 92      main (sys.argv[1:])

The program is called by -

-./test_tcm.py fsm_fname Es/No_db repetitions
-

+./test_tcm.py fsm_fname Es/No_db repetitions
+

where "fsm_fname" is the file containing the FSM specification of the tested TCM code, "Es/No_db" is the SNR in dB, and "repetitions" are the number of packets to be transmitted and received in order to @@ -312,7 +309,7 @@ error rate.

The FSM is first intantiated in "main" by

-    f=trellis.fsm(fname)
+ 62      f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...)

Each packet has size Kb bits (we choose Kb to be a multiple of 16 so that all bits fit nicely into shorts and can be generated by the lfsr GNU Radio). @@ -321,9 +318,9 @@ of bitspersymbol=log₂( I ). The Kb/16 shorts are now unpacked to K=Kb/bitspersymbol input symbols that will drive the FSM encoder.

-    Kb=1024*16  # packet size in bits (make it multiple of 16 so it can be packed in a short)
-    bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol
-    K=Kb/bitspersymbol # packet size in trellis steps
+ 63      Kb=1024*16  # packet size in bits (make it multiple of 16 so it can be packed in a short)
+ 64      bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol
+ 65      K=Kb/bitspersymbol # packet size in trellis steps

The FSM will produce K output symbols (remeber the FSM produces always one output symbol for each input symbol). Each of these symbols needs to be modulated. Since we are simulating the communication system, we need not simulate the actual waveforms. An M-ary, N-dimensional modulation is completely specified by a set of M, N-dimensional real vectors. In "fsm_utils.py" file we give a number of useful modulations with the following format: modulation = (N,constellation), where @@ -336,23 +333,23 @@ For instance, 4-ary PAM is represented as Clearly, M should be equal to the cardinality of the FSM output, O. Finally the average symbol energy and noise variance are calculated.

-    modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations
-    dimensionality = modulation[0]
-    constellation = modulation[1]
-    if len(constellation)/dimensionality != f.O():
-        sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n')
-        sys.exit (1)
-    # calculate average symbol energy
-    Es = 0
-    for i in range(len(constellation)):
-        Es = Es + constellation[i]**2
-    Es = Es / (len(constellation)/dimensionality)
-    N0=Es/pow(10.0,esn0_db/10.0); # noise variance
+ 66      modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations
+ 67      dimensionality = modulation[0]
+ 68      constellation = modulation[1]
+ 69      if len(constellation)/dimensionality != f.O():
+ 70          sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n')
+ 71          sys.exit (1)
+ 72      # calculate average symbol energy
+ 73      Es = 0
+ 74      for i in range(len(constellation)):
+ 75          Es = Es + constellation[i]**2
+ 76      Es = Es / (len(constellation)/dimensionality)
+ 77      N0=Es/pow(10.0,esn0_db/10.0); # noise variance

Then, "run_test" is called with a different "seed" so that we get different noise realizations.

-        (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations
+ 82          (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations

Let us examine now the "run_test" function. First we set up the transmitter blocks. @@ -361,25 +358,27 @@ symbols consistent with the FSM input alphabet. The FSm encoder requires the FSM specification, and an initial state (which is set to 0 in this example).

-    # 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
+ 15      # TX
+ 16      src = gr.lfsr_32k_source_s()
+ 17      src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts
+ 18      s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality
+ 19      enc = trellis.encoder_ss(f,0) # initial state = 0

+We now need to modulate the FSM output symbols. The "chunks_to_symbols_sf" is essentially a memoryless mapper which for each input symbol y_k outputs a sequence of N numbers ci1,ci2,...,ciN representing the coordianates of the constellation symbol c_i with i=y_k.

-    mod = gr.chunks_to_symbols_sf(constellation,dimensionality)
+ 20      mod = gr.chunks_to_symbols_sf(constellation,dimensionality)

The channel is AWGN with appropriate noise variance. For each transmitted symbol c_k=(ck1,ck2,...,ckN) we receive a noisy version r_k=(rk1,rk2,...,rkN).

-    add = gr.add_ff()
-    noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)
+ 22      # CHANNEL
+ 23      add = gr.add_ff()
+ 24      noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)

Part of the design methodology was to decouple the FSM and VA from the details of the modulation, channel, receiver front-end etc. @@ -408,8 +407,8 @@ do hard decision demodulation and feed the VA with symbol Hamming distances, or even bit Hamming distances, etc. These are all implemented in "metrics_f".

-    # RX
-    metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi           
+ 26      # RX
+ 27      metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi

Now the VA can run once it is supplied by the initial and final states. The initial state is known to be 0; the final state is usually @@ -418,14 +417,14 @@ In this example, we always send the the same info sequence (we only randomize no or final state). The VA outputs the estimates of the symbols x_k which are then packed to shorts and compared with the transmitted sequence.

-    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();
+ 28      va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set.
+ 29      fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
+ 30      dst = gr.check_lfsr_32k_s();

The function returns the number of shorts and the number of shorts in error. Observe that this way the estimated error rate refers to 16-bit-symbol error rate.

-return (ntotal,ntotal-nright)
+ 48      return (ntotal,ntotal-nright)

Future Work

Improve the documentation :-)
@@ -437,10 +436,11 @@ Optimize the VA code. Provide implementation of soft-input soft-output (SISO) decoders for potential use in concatenated systems. Also a host of suboptimal decoders, eg, sphere decoding, M- and T- algorithms, sequential decoding, etc. +can be implemented.
Although turbo decoding is rediculously slow in software, -we can design it in pronciple. The question is, should -we use the FSM and SISO abstractions and cnnect them -through GNU radio or should we implement turbo-decoding +we can design it in principle. One question is, whether we should +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).

diff --git a/gr-trellis/doc/gr-trellis.xml b/gr-trellis/doc/gr-trellis.xml index f34ba78e3..dd4e4c81d 100644 --- a/gr-trellis/doc/gr-trellis.xml +++ b/gr-trellis/doc/gr-trellis.xml @@ -1,7 +1,7 @@ + ]>

@@ -311,110 +311,13 @@ the VA performing MLSD. The program source is as follows. - - - -#!/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 random -import fsm_utils - -def run_test (f,Kb,bitspersymbol,K,dimensionality,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 - mod = gr.chunks_to_symbols_sf(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,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() - - # A bit of cheating: run the program once and print the - # final encoder state.. - # Then put it as the last argument in the viterbi block - #print "final state = " , enc.ST() - - ntotal = dst.ntotal () - nright = dst.nright () - runlength = dst.runlength () - return (ntotal,ntotal-nright) - - -def main(args): - nargs = len (args) - if nargs == 3: - fname=args[0] - esn0_db=float(args[1]) # Es/No in dB - rep=int(args[2]) # number of times the experiment is run to collect enough errors - else: - sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db repetitions\n') - sys.exit (1) - - # system parameters - f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) - Kb=1024*16 # packet size in bits (make it multiple of 16 so it can be packed in a short) - bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol - K=Kb/bitspersymbol # packet size in trellis steps - modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations - dimensionality = modulation[0] - constellation = modulation[1] - if len(constellation)/dimensionality != f.O(): - sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') - sys.exit (1) - # calculate average symbol energy - Es = 0 - for i in range(len(constellation)): - Es = Es + constellation[i]**2 - Es = Es / (len(constellation)/dimensionality) - N0=Es/pow(10.0,esn0_db/10.0); # noise variance - - tot_s=0 - terr_s=0 - for i in range(rep): - (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,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 - if (i%100==0): - print i,s,e,tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s) - # estimate of the (short) error rate - print tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s) - - -if __name__ == '__main__': - main (sys.argv[1:]) - +&test_tcm_listing; The program is called by - - + ./test_tcm.py fsm_fname Es/No_db repetitions - - + where "fsm_fname" is the file containing the FSM specification of the tested TCM code, "Es/No_db" is the SNR in dB, and "repetitions" are the number of packets to be transmitted and received in order to @@ -426,7 +329,7 @@ error rate. The FSM is first intantiated in "main" by - f=trellis.fsm(fname) + 62 f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) @@ -444,9 +347,9 @@ unpacked to K=Kb/bitspersymbol input symbols that will drive the FSM encoder. - Kb=1024*16 # packet size in bits (make it multiple of 16 so it can be packed in a short) - bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol - K=Kb/bitspersymbol # packet size in trellis steps + 63 Kb=1024*16 # packet size in bits (make it multiple of 16 so it can be packed in a short) + 64 bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol + 65 K=Kb/bitspersymbol # packet size in trellis steps @@ -464,18 +367,18 @@ Clearly, M should be equal to the cardinality of the FSM output, O. Finally the average symbol energy and noise variance are calculated. - modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations - dimensionality = modulation[0] - constellation = modulation[1] - if len(constellation)/dimensionality != f.O(): - sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') - sys.exit (1) - # calculate average symbol energy - Es = 0 - for i in range(len(constellation)): - Es = Es + constellation[i]**2 - Es = Es / (len(constellation)/dimensionality) - N0=Es/pow(10.0,esn0_db/10.0); # noise variance + 66 modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations + 67 dimensionality = modulation[0] + 68 constellation = modulation[1] + 69 if len(constellation)/dimensionality != f.O(): + 70 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') + 71 sys.exit (1) + 72 # calculate average symbol energy + 73 Es = 0 + 74 for i in range(len(constellation)): + 75 Es = Es + constellation[i]**2 + 76 Es = Es / (len(constellation)/dimensionality) + 77 N0=Es/pow(10.0,esn0_db/10.0); # noise variance @@ -485,7 +388,7 @@ Then, "run_test" is called with a different "seed" so that we get different noise realizations. - (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations + 82 (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations @@ -499,25 +402,25 @@ The FSm encoder requires the FSM specification, and an initial state (which is set to 0 in this example). - # 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 + 15 # TX + 16 src = gr.lfsr_32k_source_s() + 17 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts + 18 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality + 19 enc = trellis.encoder_ss(f,0) # initial state = 0 - +We now need to modulate the FSM output symbols. The "chunks_to_symbols_sf" is essentially a memoryless mapper which for each input symbol y_k outputs a sequence of N numbers ci1,ci2,...,ciN representing the coordianates of the constellation symbol c_i with i=y_k. - mod = gr.chunks_to_symbols_sf(constellation,dimensionality) + 20 mod = gr.chunks_to_symbols_sf(constellation,dimensionality) @@ -526,9 +429,9 @@ For each transmitted symbol c_k=(ck1,ck2,...,ckN) we receive a noisy version r_k=(rk1,rk2,...,rkN). - # CHANNEL - add = gr.add_ff() - noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) + 22 # CHANNEL + 23 add = gr.add_ff() + 24 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) @@ -562,8 +465,8 @@ symbol Hamming distances, or even bit Hamming distances, etc. These are all implemented in "metrics_f". - # RX - metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi + 26 # RX + 27 metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi @@ -575,9 +478,9 @@ or final state). The VA outputs the estimates of the symbols x_k which are then packed to shorts and compared with the transmitted sequence. - 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(); + 28 va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set. + 29 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts + 30 dst = gr.check_lfsr_32k_s(); @@ -588,7 +491,7 @@ The function returns the number of shorts and the number of shorts in error. Obs 16-bit-symbol error rate. - return (ntotal,ntotal-nright) + 48 return (ntotal,ntotal-nright) @@ -596,7 +499,7 @@ The function returns the number of shorts and the number of shorts in error. Obs - + Future Work @@ -637,7 +540,7 @@ can be implemented. Although turbo decoding is rediculously slow in software, we can design it in principle. One question is, whether we should use the encoder, and SISO blocks and connect them -through GNU radio or should we implement turbo-decoding +through GNU radio or we should implement turbo-decoding as a single block (issues with buffering between blocks). diff --git a/gr-trellis/doc/make_numbered_listing.py b/gr-trellis/doc/make_numbered_listing.py new file mode 100755 index 000000000..889c2d78d --- /dev/null +++ b/gr-trellis/doc/make_numbered_listing.py @@ -0,0 +1,45 @@ +#!/usr/bin/env python + +import sys +import os, os.path +from optparse import OptionParser + +def quote_line (line): + line = line.replace ('&', '&') + line = line.replace ('<', '<') + line = line.replace ('>', '>') + line = line.replace ("'", ''') + line = line.replace ('"', '"') + return line + +def generate_listing (input_filename, title=None): + inf = open (input_filename, "r") + output_filename = os.path.basename (input_filename) + '.xml' + outf = open (output_filename, "w") + outf.write ('\n') + # outf.write ('\n' % (input_filename,)) + # if not title: + # title = input_filename + # outf.write ('') + # outf.write (title) + # outf.write ('\n') + outf.write ('\n'); + + lineno = 0 + for line in inf: + line = line.expandtabs (8) + line = quote_line (line) + lineno = lineno + 1 + outf.write ('%3d %s' % (lineno, line)) + + outf.write ('\n') + # outf.write ('\n') + + +def main (): + for file in sys.argv[1:]: + generate_listing (file) + +if __name__ == '__main__': + main () + diff --git a/gr-trellis/doc/test_tcm.py b/gr-trellis/doc/test_tcm.py index 02d1e6c5c..bf93a421f 100644 --- a/gr-trellis/doc/test_tcm.py +++ b/gr-trellis/doc/test_tcm.py @@ -12,67 +12,42 @@ import fsm_utils def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed): fg = gr.flow_graph () - # TX - #packet = [0]*Kb - #for i in range(Kb-1*16): # last 16 bits = 0 to drive the final state to 0 - #packet[i] = random.randint(0, 1) # random 0s and 1s - #src = gr.vector_source_s(packet,False) src = gr.lfsr_32k_source_s() src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts - #b2s = gr.unpacked_to_packed_ss(1,gr.GR_MSB_FIRST) # pack bits 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 mod = gr.chunks_to_symbols_sf(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,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 - #s2b = gr.packed_to_unpacked_ss(1,gr.GR_MSB_FIRST) # unpack shorts to bits - #dst = gr.vector_sink_s(); dst = gr.check_lfsr_32k_s(); - fg.connect (src,src_head,s2fsmi,enc,mod) - #fg.connect (src,b2s,s2fsmi,enc,mod) fg.connect (mod,(add,0)) fg.connect (noise,(add,1)) fg.connect (add,metrics) fg.connect (metrics,va,fsmi2s,dst) - #fg.connect (metrics,va,fsmi2s,s2b,dst) - fg.run() # A bit of cheating: run the program once and print the - # final encoder state.. + # final encoder state. # Then put it as the last argument in the viterbi block #print "final state = " , enc.ST() ntotal = dst.ntotal () nright = dst.nright () runlength = dst.runlength () - #ntotal = len(packet) - #if len(dst.data()) != ntotal: - #print "Error: not enough data\n" - #nright = 0; - #for i in range(ntotal): - #if packet[i]==dst.data()[i]: - #nright=nright+1 - #else: - #print "Error in ", i return (ntotal,ntotal-nright) - - def main(args): nargs = len (args) if nargs == 3: @@ -101,8 +76,6 @@ def main(args): Es = Es / (len(constellation)/dimensionality) N0=Es/pow(10.0,esn0_db/10.0); # noise variance - - tot_s=0 terr_s=0 for i in range(rep): @@ -111,10 +84,9 @@ def main(args): terr_s=terr_s+e if (i%100==0): print i,s,e,tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s) - # estimate of the (short or bit) error rate + # estimate of the (short) error rate print tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s) if __name__ == '__main__': main (sys.argv[1:]) - diff --git a/gr-trellis/doc/test_tcm.py.xml b/gr-trellis/doc/test_tcm.py.xml new file mode 100644 index 000000000..ff15f4476 --- /dev/null +++ b/gr-trellis/doc/test_tcm.py.xml @@ -0,0 +1,95 @@ + + + 1 #!/usr/bin/env python + 2 + 3 from gnuradio import gr + 4 from gnuradio import audio + 5 from gnuradio import trellis + 6 from gnuradio import eng_notation + 7 import math + 8 import sys + 9 import random + 10 import fsm_utils + 11 + 12 def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed): + 13 fg = gr.flow_graph () + 14 + 15 # TX + 16 src = gr.lfsr_32k_source_s() + 17 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts + 18 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality + 19 enc = trellis.encoder_ss(f,0) # initial state = 0 + 20 mod = gr.chunks_to_symbols_sf(constellation,dimensionality) + 21 + 22 # CHANNEL + 23 add = gr.add_ff() + 24 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed) + 25 + 26 # RX + 27 metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi + 28 va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set. + 29 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts + 30 dst = gr.check_lfsr_32k_s(); + 31 + 32 fg.connect (src,src_head,s2fsmi,enc,mod) + 33 fg.connect (mod,(add,0)) + 34 fg.connect (noise,(add,1)) + 35 fg.connect (add,metrics) + 36 fg.connect (metrics,va,fsmi2s,dst) + 37 + 38 fg.run() + 39 + 40 # A bit of cheating: run the program once and print the + 41 # final encoder state. + 42 # Then put it as the last argument in the viterbi block + 43 #print "final state = " , enc.ST() + 44 + 45 ntotal = dst.ntotal () + 46 nright = dst.nright () + 47 runlength = dst.runlength () + 48 return (ntotal,ntotal-nright) + 49 + 50 + 51 def main(args): + 52 nargs = len (args) + 53 if nargs == 3: + 54 fname=args[0] + 55 esn0_db=float(args[1]) # Es/No in dB + 56 rep=int(args[2]) # number of times the experiment is run to collect enough errors + 57 else: + 58 sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db repetitions\n') + 59 sys.exit (1) + 60 + 61 # system parameters + 62 f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...) + 63 Kb=1024*16 # packet size in bits (make it multiple of 16 so it can be packed in a short) + 64 bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol + 65 K=Kb/bitspersymbol # packet size in trellis steps + 66 modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations + 67 dimensionality = modulation[0] + 68 constellation = modulation[1] + 69 if len(constellation)/dimensionality != f.O(): + 70 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n') + 71 sys.exit (1) + 72 # calculate average symbol energy + 73 Es = 0 + 74 for i in range(len(constellation)): + 75 Es = Es + constellation[i]**2 + 76 Es = Es / (len(constellation)/dimensionality) + 77 N0=Es/pow(10.0,esn0_db/10.0); # noise variance + 78 + 79 tot_s=0 + 80 terr_s=0 + 81 for i in range(rep): + 82 (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations + 83 tot_s=tot_s+s + 84 terr_s=terr_s+e + 85 if (i%100==0): + 86 print i,s,e,tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s) + 87 # estimate of the (short) error rate + 88 print tot_s,terr_s, '%e' % ((1.0*terr_s)/tot_s) + 89 + 90 + 91 if __name__ == '__main__': + 92 main (sys.argv[1:]) + -- cgit