Duplex Modem

Duplex modems represent the signal processing chain of a communication device simulatenously transmitting and receiving information, implementing the digital signal processing before digital-to-analog conversion and after analog-to-digital conversion, respectively. They are a combination of a Transmitting Modem and a Receiving Modem.

After a DuplexModem is added as a type of Transmitter to a Device, a call to Device.transmit will be delegated to TransmittingModem._transmit(). Similarly, after a DuplexModem is added as a type of Receiver to a Device, a call to Device.receive will be delegated to ReceivingModem._receive()

# Initialize a new simulation considering a single device
simulation = Simulation()
device = simulation.new_device(carrier_frequency=1e10)

# Configure the link modeling the devices' transmit DSP
modem = DuplexModem(device=device)

# Configure the links's waveform
waveform = RootRaisedCosineWaveform(
    oversampling_factor=4,
    symbol_rate=1e6,
    num_preamble_symbols=16,
    num_data_symbols=32,
    modulation_order=64,
)
modem.waveform = waveform

For a detailed description of the transmit and receive routines, refer to the Transmitting Modem and a Receiving Modem of the base classes.

The barebone configuration can be extend by additional components such as Custom Bit Sources, Synchronization, Stream Precoding, Channel Estimation, Symbol Precoding, Channel Equalization and Bit Encoders:

# Configure the links's waveform
waveform = RootRaisedCosineWaveform(
    oversampling_factor=4,
    symbol_rate=1e6,
    num_preamble_symbols=16,
    num_data_symbols=32,
    modulation_order=64,
)
modem.waveform = waveform

# Configure a custom bits source for the modem
modem.bits_source = RandomBitsSource(seed=42)

# Configure the waveform's synchronization routine
modem.waveform.synchronization = SingleCarrierCorrelationSynchronization()

# Add a custom stream precoding to the modem
modem.transmit_stream_coding[0] = ConventionalBeamformer()
modem.receive_stream_coding[0] = ConventionalBeamformer()

# Add a custom symbol precoding to the modem
modem.precoding[0] = DFT()

# Configure the waveform's channel estimation routine
modem.waveform.channel_estimation = SingleCarrierLeastSquaresChannelEstimation()

# Configure the waveform's channel equalization routine
modem.waveform.channel_equalization = SingleCarrierZeroForcingChannelEqualization()

# Add forward error correction encodings to the transmitted bit stream
modem.encoder_manager.add_encoder(RepetitionEncoder(32, 3))
modem.encoder_manager.add_encoder(BlockInterleaver(192, 32))

class DuplexModem(*args, bits_source=None, selected_transmit_ports=None, selected_receive_ports=None, **kwargs)

Bases: TransmittingModem, ReceivingModem

Representation of a wireless modem simultaneously transmitting and receiving.

Parameters:

• bits_source (BitsSource, optional) – Source configuration of communication bits transmitted by this modem. Bits are randomly generated by default.

• selected_transmit_ports (Sequence[int] | None) – Indices of antenna ports selected for transmission from the operated Device's antenna array. If not specified, all available ports will be considered.

• selected_receive_ports (Sequence[int] | None) – Indices of antenna ports selected for reception from the operated Device's antenna array. If not specified, all available ports will be considered.

• *args – Modem initialization parameters. Refer to TransmittingModem and ReceivingModem for further details.

• **kwargs – Modem initialization parameters. Refer to TransmittingModem and ReceivingModem for further details.

property device: Device | None

Device this object is assigned to.

None if this object is currently considered floating / unassigned.

property receiving_device: Device | None

Receiving device operated by the modem.

None if the device is unspecified.

property transmitting_device: Device | None

Tranmsitting device operated by the modem.

None if the device is unspecified.

yaml_tag: Optional[str] = 'Modem'

YAML serialization tag