diff options
Diffstat (limited to 'gr-digital/python/digital/ofdm_txrx.py')
| -rw-r--r-- | gr-digital/python/digital/ofdm_txrx.py | 116 |
1 files changed, 70 insertions, 46 deletions
diff --git a/gr-digital/python/digital/ofdm_txrx.py b/gr-digital/python/digital/ofdm_txrx.py index 76bf337b8d..b1ebc9e9c2 100644 --- a/gr-digital/python/digital/ofdm_txrx.py +++ b/gr-digital/python/digital/ofdm_txrx.py @@ -63,6 +63,7 @@ _seq_seed = 42 def _get_active_carriers(fft_len, occupied_carriers, pilot_carriers): + """ Returns a list of all carriers that at some point carry data or pilots. """ active_carriers = list() for carrier in list(occupied_carriers[0]) + list(pilot_carriers[0]): if carrier < 0: @@ -134,6 +135,8 @@ class ofdm_tx(gr.hier_block2): sync_word2: The second sync preamble symbol. This has to be filled entirely. Also used for coarse frequency offset and channel estimation. rolloff: The rolloff length in samples. Must be smaller than the CP. + debug_log: Write output into log files (Warning: creates lots of data!) + 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, @@ -160,7 +163,6 @@ class ofdm_tx(gr.hier_block2): self.pilot_symbols = pilot_symbols self.bps_header = bps_header self.bps_payload = bps_payload - n_sync_words = 1 self.sync_word1 = sync_word1 if sync_word1 is None: self.sync_word1 = _make_sync_word1(fft_len, occupied_carriers, pilot_carriers) @@ -175,8 +177,11 @@ class ofdm_tx(gr.hier_block2): if len(self.sync_word2) != fft_len: raise ValueError("Length of sync sequence(s) must be FFT length.") self.sync_word2 = list(self.sync_word2) - n_sync_words = 2 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 ### Header modulation ################################################ crc = digital.crc32_bb(False, self.packet_length_tag_key) header_constellation = _get_constellation(bps_header) @@ -184,42 +189,39 @@ class ofdm_tx(gr.hier_block2): 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 + 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_payload_mux = blocks.tagged_stream_mux(gr.sizeof_gr_complex*1, self.packet_length_tag_key) - self.connect(self, crc, header_gen, header_mod, (header_payload_mux, 0)) + self.connect( + 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()) - if scramble_bits: - self.connect( - crc, - digital.additive_scrambler_bb( - 0x8a, 0x7f, 7, - bits_per_byte=bps_payload, - reset_tag_key=self.packet_length_tag_key - ), - blocks.repack_bits_bb( - 8, # Unpack 8 bits per byte - bps_payload, - self.packet_length_tag_key - ), - payload_mod - ) - else: - self.connect( - crc, - blocks.repack_bits_bb( - 8, # Unpack 8 bits per byte - bps_payload, - self.packet_length_tag_key - ), - payload_mod - ) + 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=bps_payload, + reset_tag_key=self.packet_length_tag_key + ) self.connect( + crc, + payload_scrambler, + blocks.repack_bits_bb( + 8, # Unpack 8 bits per byte + bps_payload, + self.packet_length_tag_key + ), payload_mod, (header_payload_mux, 1) ) @@ -246,8 +248,8 @@ class ofdm_tx(gr.hier_block2): ) self.connect(header_payload_mux, allocator, ffter, cyclic_prefixer, self) if debug_log: - self.connect(allocator, blocks.file_sink(8*64, 'tx-post-allocator.dat')) - self.connect(cyclic_prefixer, blocks.file_sink(8, '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): @@ -312,6 +314,10 @@ class ofdm_rx(gr.hier_block2): 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 ### Sync ############################################################ sync_detect = digital.ofdm_sync_sc_cfb(fft_len, cp_len) delay = blocks.delay(gr.sizeof_gr_complex, fft_len+cp_len) @@ -357,10 +363,19 @@ class ofdm_rx(gr.hier_block2): frame_length_tag_key, packet_num_tag_key, bps_header, - bps_payload + bps_payload, + scramble_header=scramble_bits ) header_parser = digital.packet_headerparser_b(header_formatter.formatter()) - self.connect((hpd, 0), header_fft, chanest, header_eq, header_serializer, header_demod, header_parser) + self.connect( + (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')) @@ -368,7 +383,7 @@ class ofdm_rx(gr.hier_block2): 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(header_demod, blocks.file_sink(1, 'post-hdr-demod.dat')) + self.connect(header_descrambler, blocks.file_sink(1, 'post-hdr-demod.dat')) ### Payload demod #################################################### payload_fft = fft.fft_vcc(self.fft_len, True, (), True) payload_constellation = _get_constellation(bps_payload) @@ -391,20 +406,29 @@ class ofdm_rx(gr.hier_block2): 1 # Skip 1 symbol (that was already in the header) ) 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=bps_payload, + reset_tag_key=self.packet_length_tag_key + ) repack = blocks.repack_bits_bb(bps_payload, 8, self.packet_length_tag_key, True) - crc = digital.crc32_bb(True, self.packet_length_tag_key) - self.connect((hpd, 1), payload_fft, payload_eq, payload_serializer, payload_demod, repack) - if scramble_bits: - descrambler = digital.additive_scrambler_bb( - 0x8a, 0x7f, 7, - bits_per_byte=bps_payload, - reset_tag_key=self.packet_length_tag_key - ) - self.connect(repack, descrambler, crc, self) - else: - self.connect(repack, crc, self) + self.crc = digital.crc32_bb(True, self.packet_length_tag_key) + self.connect( + (hpd, 1), + payload_fft, + payload_eq, + payload_serializer, + payload_demod, + repack, + 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((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')) |