diff options
Diffstat (limited to 'gr-digital/python/digital/ofdm_txrx.py')
| -rw-r--r-- | gr-digital/python/digital/ofdm_txrx.py | 319 |
1 files changed, 184 insertions, 135 deletions
diff --git a/gr-digital/python/digital/ofdm_txrx.py b/gr-digital/python/digital/ofdm_txrx.py index 9d083c5fe2..60109ceaaa 100644 --- a/gr-digital/python/digital/ofdm_txrx.py +++ b/gr-digital/python/digital/ofdm_txrx.py @@ -31,15 +31,20 @@ _def_frame_length_tag_key = "frame_length" _def_packet_length_tag_key = "packet_length" _def_packet_num_tag_key = "packet_num" # Data and pilot carriers are same as in 802.11a -_def_occupied_carriers = (list(range(-26, -21)) + list(range(-20, -7)) + list(range(-6, 0)) + list(range(1, 7)) + list(range(8, 21)) + list(range(22, 27)),) -_def_pilot_carriers=((-21, -7, 7, 21,),) +_def_occupied_carriers = (list(range(-26, -21)) + list(range(-20, -7)) + list( + range(-6, 0)) + list(range(1, 7)) + list(range(8, 21)) + list(range(22, 27)),) +_def_pilot_carriers = ((-21, -7, 7, 21,),) _pilot_sym_scramble_seq = ( - 1,1,1,1, -1,-1,-1,1, -1,-1,-1,-1, 1,1,-1,1, -1,-1,1,1, -1,1,1,-1, 1,1,1,1, 1,1,-1,1, - 1,1,-1,1, 1,-1,-1,1, 1,1,-1,1, -1,-1,-1,1, -1,1,-1,-1, 1,-1,-1,1, 1,1,1,1, -1,-1,1,1, - -1,-1,1,-1, 1,-1,1,1, -1,-1,-1,1, 1,-1,-1,-1, -1,1,-1,-1, 1,-1,1,1, 1,1,-1,1, -1,1,-1,1, - -1,-1,-1,-1, -1,1,-1,1, 1,-1,1,-1, 1,1,1,-1, -1,1,-1,-1, -1,1,1,1, -1,-1,-1,-1, -1,-1,-1 + 1, 1, 1, 1, -1, -1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1, - + 1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, 1, 1, -1, 1, + 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, 1, - + 1, 1, -1, -1, 1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, 1, + -1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, - + 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, 1, + -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, 1, -1, - + 1, 1, -1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1 ) -_def_pilot_symbols= tuple([(x, x, x, -x) for x in _pilot_sym_scramble_seq]) +_def_pilot_symbols = tuple([(x, x, x, -x) for x in _pilot_sym_scramble_seq]) _seq_seed = 42 @@ -52,6 +57,7 @@ def _get_active_carriers(fft_len, occupied_carriers, pilot_carriers): active_carriers.append(carrier) return active_carriers + def _make_sync_word1(fft_len, occupied_carriers, pilot_carriers): """ Creates a random sync sequence for fine frequency offset and timing estimation. This is the first of typically two sync preamble symbols @@ -64,31 +70,37 @@ def _make_sync_word1(fft_len, occupied_carriers, pilot_carriers): Carrier 0 (DC carrier) is always zero. If used, carrier 1 is non-zero. This means the sync algorithm has to check on odd carriers! """ - active_carriers = _get_active_carriers(fft_len, occupied_carriers, pilot_carriers) + active_carriers = _get_active_carriers( + fft_len, occupied_carriers, pilot_carriers) numpy.random.seed(_seq_seed) bpsk = {0: numpy.sqrt(2), 1: -numpy.sqrt(2)} - sw1 = [bpsk[numpy.random.randint(2)] if x in active_carriers and x % 2 else 0 for x in range(fft_len)] + sw1 = [bpsk[numpy.random.randint( + 2)] if x in active_carriers and x % 2 else 0 for x in range(fft_len)] return numpy.fft.fftshift(sw1) + def _make_sync_word2(fft_len, occupied_carriers, pilot_carriers): """ Creates a random sync sequence for coarse frequency offset and channel estimation. This is the second of typically two sync preamble symbols for the Schmidl & Cox sync algorithm. Symbols are always BPSK symbols. """ - active_carriers = _get_active_carriers(fft_len, occupied_carriers, pilot_carriers) + active_carriers = _get_active_carriers( + fft_len, occupied_carriers, pilot_carriers) numpy.random.seed(_seq_seed) bpsk = {0: 1, 1: -1} - sw2 = [bpsk[numpy.random.randint(2)] if x in active_carriers else 0 for x in range(fft_len)] + sw2 = [bpsk[numpy.random.randint( + 2)] if x in active_carriers else 0 for x in range(fft_len)] sw2[0] = 0j return numpy.fft.fftshift(sw2) + def _get_constellation(bps): """ Returns a modulator block for a given number of bits per symbol """ constellation = { - 1: digital.constellation_bpsk(), - 2: digital.constellation_qpsk(), - 3: digital.constellation_8psk() + 1: digital.constellation_bpsk(), + 2: digital.constellation_qpsk(), + 3: digital.constellation_8psk() } try: return constellation[bps] @@ -96,6 +108,7 @@ def _get_constellation(bps): print('Modulation not supported.') exit(1) + class ofdm_tx(gr.hier_block2): """Hierarchical block for OFDM modulation. @@ -122,6 +135,7 @@ class ofdm_tx(gr.hier_block2): scramble_bits: Activates the scramblers (set this to True unless debugging) """ + def __init__(self, fft_len=_def_fft_len, cp_len=_def_cp_len, packet_length_tag_key=_def_packet_length_tag_key, occupied_carriers=_def_occupied_carriers, @@ -136,75 +150,82 @@ class ofdm_tx(gr.hier_block2): scramble_bits=False ): gr.hier_block2.__init__(self, "ofdm_tx", - gr.io_signature(1, 1, gr.sizeof_char), - gr.io_signature(1, 1, gr.sizeof_gr_complex)) + gr.io_signature(1, 1, gr.sizeof_char), + gr.io_signature(1, 1, gr.sizeof_gr_complex)) ### Param init / sanity check ######################################## - self.fft_len = fft_len - self.cp_len = cp_len + self.fft_len = fft_len + self.cp_len = cp_len self.packet_length_tag_key = packet_length_tag_key self.occupied_carriers = occupied_carriers - self.pilot_carriers = pilot_carriers - self.pilot_symbols = pilot_symbols - self.bps_header = bps_header - self.bps_payload = bps_payload + self.pilot_carriers = pilot_carriers + self.pilot_symbols = pilot_symbols + self.bps_header = bps_header + self.bps_payload = bps_payload self.sync_word1 = sync_word1 if sync_word1 is None: - self.sync_word1 = _make_sync_word1(fft_len, occupied_carriers, pilot_carriers) + self.sync_word1 = _make_sync_word1( + fft_len, occupied_carriers, pilot_carriers) else: if len(sync_word1) != self.fft_len: - raise ValueError("Length of sync sequence(s) must be FFT length.") - self.sync_words = [self.sync_word1,] + raise ValueError( + "Length of sync sequence(s) must be FFT length.") + self.sync_words = [self.sync_word1, ] if sync_word2 is None: - self.sync_word2 = _make_sync_word2(fft_len, occupied_carriers, pilot_carriers) + self.sync_word2 = _make_sync_word2( + fft_len, occupied_carriers, pilot_carriers) else: self.sync_word2 = sync_word2 if len(self.sync_word2): if len(self.sync_word2) != fft_len: - raise ValueError("Length of sync sequence(s) must be FFT length.") + raise ValueError( + "Length of sync sequence(s) must be FFT length.") self.sync_word2 = list(self.sync_word2) self.sync_words.append(self.sync_word2) if scramble_bits: self.scramble_seed = 0x7f else: - self.scramble_seed = 0x00 # We deactivate the scrambler by init'ing it with zeros + self.scramble_seed = 0x00 # We deactivate the scrambler by init'ing it with zeros ### Header modulation ################################################ crc = digital.crc32_bb(False, self.packet_length_tag_key) - header_constellation = _get_constellation(bps_header) - header_mod = digital.chunks_to_symbols_bc(header_constellation.points()) + header_constellation = _get_constellation(bps_header) + header_mod = digital.chunks_to_symbols_bc( + header_constellation.points()) formatter_object = digital.packet_header_ofdm( occupied_carriers=occupied_carriers, n_syms=1, bits_per_header_sym=self.bps_header, bits_per_payload_sym=self.bps_payload, scramble_header=scramble_bits ) - header_gen = digital.packet_headergenerator_bb(formatter_object.base(), self.packet_length_tag_key) + header_gen = digital.packet_headergenerator_bb( + formatter_object.base(), self.packet_length_tag_key) header_payload_mux = blocks.tagged_stream_mux( - itemsize=gr.sizeof_gr_complex*1, - lengthtagname=self.packet_length_tag_key, - tag_preserve_head_pos=1 # Head tags on the payload stream stay on the head + itemsize=gr.sizeof_gr_complex * 1, + lengthtagname=self.packet_length_tag_key, + tag_preserve_head_pos=1 # Head tags on the payload stream stay on the head ) self.connect( - self, - crc, - header_gen, - header_mod, - (header_payload_mux, 0) + self, + crc, + header_gen, + header_mod, + (header_payload_mux, 0) ) if debug_log: self.connect(header_gen, blocks.file_sink(1, 'tx-hdr.dat')) ### Payload modulation ############################################### payload_constellation = _get_constellation(bps_payload) - payload_mod = digital.chunks_to_symbols_bc(payload_constellation.points()) + payload_mod = digital.chunks_to_symbols_bc( + payload_constellation.points()) payload_scrambler = digital.additive_scrambler_bb( 0x8a, self.scramble_seed, 7, - 0, # Don't reset after fixed length (let the reset tag do that) - bits_per_byte=8, # This is before unpacking + 0, # Don't reset after fixed length (let the reset tag do that) + bits_per_byte=8, # This is before unpacking reset_tag_key=self.packet_length_tag_key ) payload_unpack = blocks.repack_bits_bb( - 8, # Unpack 8 bits per byte + 8, # Unpack 8 bits per byte bps_payload, self.packet_length_tag_key ) @@ -225,21 +246,24 @@ class ofdm_tx(gr.hier_block2): len_tag_key=self.packet_length_tag_key ) ffter = fft.fft_vcc( - self.fft_len, - False, # Inverse FFT - (), # No window - True # Shift + self.fft_len, + False, # Inverse FFT + (), # No window + True # Shift ) cyclic_prefixer = digital.ofdm_cyclic_prefixer( self.fft_len, - self.fft_len+self.cp_len, + self.fft_len + self.cp_len, rolloff, self.packet_length_tag_key ) - self.connect(header_payload_mux, allocator, ffter, cyclic_prefixer, self) + self.connect(header_payload_mux, allocator, + ffter, cyclic_prefixer, self) if debug_log: - self.connect(allocator, blocks.file_sink(gr.sizeof_gr_complex * fft_len, 'tx-post-allocator.dat')) - self.connect(cyclic_prefixer, blocks.file_sink(gr.sizeof_gr_complex, 'tx-signal.dat')) + self.connect(allocator, blocks.file_sink( + gr.sizeof_gr_complex * fft_len, 'tx-post-allocator.dat')) + self.connect(cyclic_prefixer, blocks.file_sink( + gr.sizeof_gr_complex, 'tx-signal.dat')) class ofdm_rx(gr.hier_block2): @@ -265,6 +289,7 @@ class ofdm_rx(gr.hier_block2): | entirely. Also used for coarse frequency offset and | channel estimation. """ + def __init__(self, fft_len=_def_fft_len, cp_len=_def_cp_len, frame_length_tag_key=_def_frame_length_tag_key, packet_length_tag_key=_def_packet_length_tag_key, @@ -280,60 +305,69 @@ class ofdm_rx(gr.hier_block2): scramble_bits=False ): gr.hier_block2.__init__(self, "ofdm_rx", - gr.io_signature(1, 1, gr.sizeof_gr_complex), - gr.io_signature(1, 1, gr.sizeof_char)) + gr.io_signature(1, 1, gr.sizeof_gr_complex), + gr.io_signature(1, 1, gr.sizeof_char)) ### Param init / sanity check ######################################## - self.fft_len = fft_len - self.cp_len = cp_len - self.frame_length_tag_key = frame_length_tag_key - self.packet_length_tag_key = packet_length_tag_key + self.fft_len = fft_len + self.cp_len = cp_len + self.frame_length_tag_key = frame_length_tag_key + self.packet_length_tag_key = packet_length_tag_key self.occupied_carriers = occupied_carriers - self.bps_header = bps_header - self.bps_payload = bps_payload + self.bps_header = bps_header + self.bps_payload = bps_payload n_sync_words = 1 if sync_word1 is None: - self.sync_word1 = _make_sync_word1(fft_len, occupied_carriers, pilot_carriers) + self.sync_word1 = _make_sync_word1( + fft_len, occupied_carriers, pilot_carriers) else: if len(sync_word1) != self.fft_len: - raise ValueError("Length of sync sequence(s) must be FFT length.") + raise ValueError( + "Length of sync sequence(s) must be FFT length.") self.sync_word1 = sync_word1 self.sync_word2 = () if sync_word2 is None: - self.sync_word2 = _make_sync_word2(fft_len, occupied_carriers, pilot_carriers) + self.sync_word2 = _make_sync_word2( + fft_len, occupied_carriers, pilot_carriers) n_sync_words = 2 elif len(sync_word2): if len(sync_word2) != fft_len: - raise ValueError("Length of sync sequence(s) must be FFT length.") + raise ValueError( + "Length of sync sequence(s) must be FFT length.") self.sync_word2 = sync_word2 n_sync_words = 2 if scramble_bits: self.scramble_seed = 0x7f else: - self.scramble_seed = 0x00 # We deactivate the scrambler by init'ing it with zeros + self.scramble_seed = 0x00 # We deactivate the scrambler by init'ing it with zeros ### Sync ############################################################ sync_detect = digital.ofdm_sync_sc_cfb(fft_len, cp_len) - delay = blocks.delay(gr.sizeof_gr_complex, fft_len+cp_len) + delay = blocks.delay(gr.sizeof_gr_complex, fft_len + cp_len) oscillator = analog.frequency_modulator_fc(-2.0 / fft_len) mixer = blocks.multiply_cc() hpd = digital.header_payload_demux( - n_sync_words+1, # Number of OFDM symbols before payload (sync + 1 sym header) + # Number of OFDM symbols before payload (sync + 1 sym header) + n_sync_words + 1, fft_len, cp_len, # FFT length, guard interval - frame_length_tag_key, # Frame length tag key + frame_length_tag_key, # Frame length tag key "", # We're not using trigger tags - True # One output item is one OFDM symbol (False would output complex scalars) + # One output item is one OFDM symbol (False would output complex scalars) + True ) self.connect(self, sync_detect) self.connect(self, delay, (mixer, 0), (hpd, 0)) self.connect((sync_detect, 0), oscillator, (mixer, 1)) self.connect((sync_detect, 1), (hpd, 1)) if debug_log: - self.connect((sync_detect, 0), blocks.file_sink(gr.sizeof_float, 'freq-offset.dat')) - self.connect((sync_detect, 1), blocks.file_sink(gr.sizeof_char, 'sync-detect.dat')) + self.connect((sync_detect, 0), blocks.file_sink( + gr.sizeof_float, 'freq-offset.dat')) + self.connect((sync_detect, 1), blocks.file_sink( + gr.sizeof_char, 'sync-detect.dat')) ### Header demodulation ############################################## - header_fft = fft.fft_vcc(self.fft_len, True, (), True) - chanest = digital.ofdm_chanest_vcvc(self.sync_word1, self.sync_word2, 1) + header_fft = fft.fft_vcc(self.fft_len, True, (), True) + chanest = digital.ofdm_chanest_vcvc( + self.sync_word1, self.sync_word2, 1) header_constellation = _get_constellation(bps_header) - header_equalizer = digital.ofdm_equalizer_simpledfe( + header_equalizer = digital.ofdm_equalizer_simpledfe( fft_len, header_constellation.base(), occupied_carriers, @@ -342,93 +376,108 @@ class ofdm_rx(gr.hier_block2): symbols_skipped=0, ) header_eq = digital.ofdm_frame_equalizer_vcvc( - header_equalizer.base(), - cp_len, - self.frame_length_tag_key, - True, - 1 # Header is 1 symbol long + header_equalizer.base(), + cp_len, + self.frame_length_tag_key, + True, + 1 # Header is 1 symbol long ) header_serializer = digital.ofdm_serializer_vcc( - fft_len, occupied_carriers, - self.frame_length_tag_key + fft_len, occupied_carriers, + self.frame_length_tag_key ) - header_demod = digital.constellation_decoder_cb(header_constellation.base()) + header_demod = digital.constellation_decoder_cb( + header_constellation.base()) header_formatter = digital.packet_header_ofdm( - occupied_carriers, 1, - packet_length_tag_key, - frame_length_tag_key, - packet_num_tag_key, - bps_header, - bps_payload, - scramble_header=scramble_bits + occupied_carriers, 1, + packet_length_tag_key, + frame_length_tag_key, + packet_num_tag_key, + bps_header, + bps_payload, + scramble_header=scramble_bits ) - header_parser = digital.packet_headerparser_b(header_formatter.formatter()) + header_parser = digital.packet_headerparser_b( + header_formatter.formatter()) self.connect( - (hpd, 0), - header_fft, - chanest, - header_eq, - header_serializer, - header_demod, - header_parser + (hpd, 0), + header_fft, + chanest, + header_eq, + header_serializer, + header_demod, + header_parser ) self.msg_connect(header_parser, "header_data", hpd, "header_data") if debug_log: - self.connect((chanest, 1), blocks.file_sink(gr.sizeof_gr_complex * fft_len, 'channel-estimate.dat')) - self.connect((chanest, 0), blocks.file_sink(gr.sizeof_gr_complex * fft_len, 'post-hdr-chanest.dat')) - self.connect((chanest, 0), blocks.tag_debug(gr.sizeof_gr_complex * fft_len, 'post-hdr-chanest')) - self.connect(header_eq, blocks.file_sink(gr.sizeof_gr_complex * fft_len, 'post-hdr-eq.dat')) - self.connect(header_serializer, blocks.file_sink(gr.sizeof_gr_complex, 'post-hdr-serializer.dat')) + self.connect((chanest, 1), blocks.file_sink( + gr.sizeof_gr_complex * fft_len, 'channel-estimate.dat')) + self.connect((chanest, 0), blocks.file_sink( + gr.sizeof_gr_complex * fft_len, 'post-hdr-chanest.dat')) + self.connect((chanest, 0), blocks.tag_debug( + gr.sizeof_gr_complex * fft_len, 'post-hdr-chanest')) + self.connect(header_eq, blocks.file_sink( + gr.sizeof_gr_complex * fft_len, 'post-hdr-eq.dat')) + self.connect(header_serializer, blocks.file_sink( + gr.sizeof_gr_complex, 'post-hdr-serializer.dat')) ### Payload demod #################################################### payload_fft = fft.fft_vcc(self.fft_len, True, (), True) payload_constellation = _get_constellation(bps_payload) payload_equalizer = digital.ofdm_equalizer_simpledfe( - fft_len, - payload_constellation.base(), - occupied_carriers, - pilot_carriers, - pilot_symbols, - symbols_skipped=1, # (that was already in the header) - alpha=0.1 + fft_len, + payload_constellation.base(), + occupied_carriers, + pilot_carriers, + pilot_symbols, + symbols_skipped=1, # (that was already in the header) + alpha=0.1 ) payload_eq = digital.ofdm_frame_equalizer_vcvc( - payload_equalizer.base(), - cp_len, - self.frame_length_tag_key + payload_equalizer.base(), + cp_len, + self.frame_length_tag_key ) payload_serializer = digital.ofdm_serializer_vcc( - fft_len, occupied_carriers, - self.frame_length_tag_key, - self.packet_length_tag_key, - 1 # Skip 1 symbol (that was already in the header) + fft_len, occupied_carriers, + self.frame_length_tag_key, + self.packet_length_tag_key, + 1 # Skip 1 symbol (that was already in the header) ) - payload_demod = digital.constellation_decoder_cb(payload_constellation.base()) + payload_demod = digital.constellation_decoder_cb( + payload_constellation.base()) self.payload_descrambler = digital.additive_scrambler_bb( 0x8a, self.scramble_seed, 7, - 0, # Don't reset after fixed length - bits_per_byte=8, # This is after packing + 0, # Don't reset after fixed length + bits_per_byte=8, # This is after packing reset_tag_key=self.packet_length_tag_key ) - payload_pack = blocks.repack_bits_bb(bps_payload, 8, self.packet_length_tag_key, True) + payload_pack = blocks.repack_bits_bb( + bps_payload, 8, self.packet_length_tag_key, True) self.crc = digital.crc32_bb(True, self.packet_length_tag_key) self.connect( - (hpd, 1), - payload_fft, - payload_eq, - payload_serializer, - payload_demod, - payload_pack, - self.payload_descrambler, - self.crc, - self + (hpd, 1), + payload_fft, + payload_eq, + payload_serializer, + payload_demod, + payload_pack, + self.payload_descrambler, + self.crc, + self ) if debug_log: - self.connect((hpd, 1), blocks.tag_debug(gr.sizeof_gr_complex*fft_len, 'post-hpd')) - self.connect(payload_fft, blocks.file_sink(gr.sizeof_gr_complex*fft_len, 'post-payload-fft.dat')) - self.connect(payload_eq, blocks.file_sink(gr.sizeof_gr_complex*fft_len, 'post-payload-eq.dat')) - self.connect(payload_serializer, blocks.file_sink(gr.sizeof_gr_complex, 'post-payload-serializer.dat')) - self.connect(payload_demod, blocks.file_sink(1, 'post-payload-demod.dat')) - self.connect(payload_pack, blocks.file_sink(1, 'post-payload-pack.dat')) - self.connect(self.crc, blocks.file_sink(1, 'post-payload-crc.dat')) + self.connect((hpd, 1), blocks.tag_debug( + gr.sizeof_gr_complex * fft_len, 'post-hpd')) + self.connect(payload_fft, blocks.file_sink( + gr.sizeof_gr_complex * fft_len, 'post-payload-fft.dat')) + self.connect(payload_eq, blocks.file_sink( + gr.sizeof_gr_complex * fft_len, 'post-payload-eq.dat')) + self.connect(payload_serializer, blocks.file_sink( + gr.sizeof_gr_complex, 'post-payload-serializer.dat')) + self.connect(payload_demod, blocks.file_sink( + 1, 'post-payload-demod.dat')) + self.connect(payload_pack, blocks.file_sink( + 1, 'post-payload-pack.dat')) + self.connect(self.crc, blocks.file_sink(1, 'post-payload-crc.dat')) |