def send_pkt(self, payload='', eof=False):
"""
Send the payload.
@param payload: data to send
@type payload: string
"""
if eof:
msg = gr.message(1) # tell self._pkt_input we're not sending any more packets
else:
info = ofdm_packet_utils.get_info(payload, self._regime, self._symbol_time)
N_cbps = info["N_cbps"]
N_bpsc = info["N_bpsc"]
N_rate = info["rate"]
N_sym = info["N_sym"]
(pkt,Length) = ofdm_packet_utils.ieee802_11_make(payload,self._regime, self._symbol_time)
#print ofdm_packet_utils.asciistr_to_bin(pkt)
#print "Length ", Length
(pkt_scrambled,Length) = ofdm_packet_utils.scrambler(pkt,Length)
#print ofdm_packet_utils.asciistr_to_bin(pkt_scrambled)
#print "Length after scrambling ", Length
pkt_coded = ofdm_packet_utils.conv_encoder(pkt_scrambled, Length, self._regime, N_cbps, N_bpsc, N_sym, N_rate)
#print ofdm_packet_utils.asciistr_to_bin(pkt_coded)
pkt_interleaved = ofdm_packet_utils.interleaver(pkt_coded , self._regime, N_cbps, N_bpsc)
#print ofdm_packet_utils.asciistr_to_bin(pkt_interleaved)
msg = gr.message_from_string(pkt_interleaved)
#if self._pkt_input.msgq().full_p():
# print "Queue full, are u sure you want to insert stuff in it?"
#if self._pkt_input.msgq().empty_p():
# print "Queue empty, feel free to insert stuff in it!"
self._pkt_input.msgq().insert_tail(msg)
def __init__(self, count, options, payload='', msgq_limit=2, pad_for_usrp=False):
"""
Hierarchical block for sending packets
Packets to be sent are enqueued by calling send_pkt.
The output is the complex modulated signal at baseband.
@param options: pass modulation options from higher layers (fft length, occupied tones, etc.)
@param msgq_limit: maximum number of messages in message queue
@type msgq_limit: int
@param pad_for_usrp: If true, packets are padded such that they end up a multiple of 128 samples
"""
gr.hier_block2.__init__(self, "ofdm_mod",
gr.io_signature(0, 0, 0), # Input signature
gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
self._fft_length = 64
self._total_sub_carriers = 53
self._data_subcarriers = 48
self._cp_length = 16
self._regime = options.regime
self._symbol_length = self._fft_length + self._cp_length
# assuming we have 100Ms/s going to the USRP2 and 80 samples per symbol
# we can calculate the OFDM symboltime (in microseconds)
# depending on the interpolation factor
self._symbol_time = 100000000*(self._symbol_length )/(100*options.bandwidth)
#print self._symbol_time
win = []
if(self._regime == "1" or self._regime == "2"):
rotated_const = ofdm_packet_utils.bpsk(self)
elif (self._regime == "3" or self._regime == "4"):
rotated_const = ofdm_packet_utils.qpsk(self)
elif(self._regime == "5" or self._regime == "6"):
rotated_const = ofdm_packet_utils.qam16(self)
elif(self._regime == "7" or self._regime == "8"):
rotated_const = ofdm_packet_utils.qam64(self)
# map groups of bits to complex symbols
self._pkt_input = gr_ieee802_11.ofdm_symbol_mapper(rotated_const, msgq_limit, self._data_subcarriers, self._fft_length,False)
#self._pkt_input = digital_swig.ofdm_mapper_bcv(rotated_const,
# msgq_limit,
# self._data_subcarriers,
# self._fft_length)
# insert pilot symbols
self.pilot = gr_ieee802_11.ofdm_pilot_insert(self._data_subcarriers)
# move subcarriers to their designated place and insert DC
self.cmap = gr_ieee802_11.ofdm_carrier_mapper(self._fft_length, self._total_sub_carriers)
# inverse fast fourier transform
self.ifft = gr.fft_vcc(self._fft_length, False, win, False)
# add cyclic prefix
self.cp_adder = digital_swig.ofdm_cyclic_prefixer(self._fft_length, self._symbol_length)
# scale accordingly
self.scale = gr.multiply_const_cc(1.0 / math.sqrt(self._fft_length))
# we need to know the number of OFDM data symbols for preamble and zerogap
info = ofdm_packet_utils.get_info(payload, options.regime, self._symbol_time)
N_sym = info["N_sym"]
# add training sequence
self.preamble= ofdm_packet_utils.insert_preamble(self._symbol_length, N_sym)
# append zero samples at the end (receiver needs that to decode)
self.zerogap = ofdm_packet_utils.insert_zerogap(self._symbol_length, N_sym)
# repeat the frame a number of times
self.repeat = gr_ieee802_11.ofdm_symbol_repeater(self._symbol_length, options.repetition, N_sym)
self.s2v = gr.stream_to_vector(gr.sizeof_gr_complex , self._symbol_length)
self.v2s = gr.vector_to_stream(gr.sizeof_gr_complex , self._symbol_length)
self.gr_complex_to_imag_0 = gr.complex_to_imag(1)
self.gr_complex_to_real_0 = gr.complex_to_real(1)
self.gr_float_to_complex_0 = gr.float_to_complex(1)
self.connect((self.v2s, 0), (self.gr_complex_to_imag_0, 0))
self.connect((self.v2s, 0), (self.gr_complex_to_real_0, 0))
self.connect((self.gr_complex_to_imag_0, 0), (self.gr_float_to_complex_0, 1))
self.connect((self.gr_complex_to_real_0, 0), (self.gr_float_to_complex_0, 0))
self.connect((self.gr_float_to_complex_0, 0), (self))
# connect the blocks
self.connect((self._pkt_input, 0), (self.pilot, 0))
self.connect((self._pkt_input,1), (self.preamble, 1))
self.connect((self.preamble,1), (self.zerogap, 1))
#if options.repetition == 1:
# self.connect(self.pilot, self.cmap, self.ifft, self.cp_adder, self.scale, self.s2v, \
# self.preamble, self.zerogap, self.v2s)
#elif options.repetition > 1:
self.connect(self.pilot, self.cmap, self.ifft, self.cp_adder, self.scale, self.s2v, self.preamble, self.zerogap, self.repeat, self.v2s)
#else:
# print"Error: repetiton must be a integer number >= 1 \n"
# sys.exit(1)
if options.log:
self.connect((self._pkt_input), gr.file_sink(gr.sizeof_gr_complex * self._data_subcarriers, "ofdm_symbol_mapper"+count+".dat"))
self.connect(self.pilot, gr.file_sink(gr.sizeof_gr_complex * (5 + self._data_subcarriers), "ofdm_pilot_insert"+count+".dat"))
self.connect(self.cmap, gr.file_sink(gr.sizeof_gr_complex * self._fft_length, "ofdm_carrier_mapper"+count+".dat"))
self.connect(self.ifft, gr.file_sink(gr.sizeof_gr_complex * self._fft_length, "ofdm_ifft_er"+count+".dat"))
self.connect(self.cp_adder, gr.file_sink(gr.sizeof_gr_complex, "ofdm_cp_insert"+count+".dat"))
self.connect(self.scale, gr.file_sink(gr.sizeof_gr_complex, "ofdm_scale_er"+count+".dat"))
self.connect(self.preamble, gr.file_sink(gr.sizeof_gr_complex * self._symbol_length, "ofdm_preamble_insert"+count+".dat"))
self.connect(self.zerogap, gr.file_sink(gr.sizeof_gr_complex * self._symbol_length, "ofdm_zerogap_insert"+count+".dat"))
self.connect(self.repeat, gr.file_sink(gr.sizeof_gr_complex * self._symbol_length, "ofdm_symbol_repeater"+count+".dat"))