SionnaRT Channel¶

The SionnaRTChannel is an adapter for Sionna Ray Tracing module.

It is deterministic, defined by the given sionna.rt.Scene. Meaning, given same devices and positions, different channel samples (SionnaRTChannelSample) and realizations (SionnaRTChannelRealization) would not introduce any random changes and would produce equal state and propagation results.

This channel model requires sionna.rt.Scene to operate. It should be loaded with sionna.rt.load_scene and provided to the SionnaRTChannel __init__ method.

Current assumptions in the adapter implementation are:

All the transmitting and receiving antennas utilize isometric pattern (“iso”) and a single vertical polarization (“V”).
The antenna arrays are synthetic.
The delays are not normalized.
If not a single ray hit was cought, then a zeroed signal or state are returned.

It should be noted that sionna.rt.Scene is a singleton class. So when a new scene is loaded, a conflict with the previous existing instance will occure. Thus usage of several scenes at once must be avoided.

        classDiagram

   direction LR

   class SionnaRTChannel {

      _realize() : SionnaRTChannelRealization
   }

   class SionnaRTChannelRealization {

      _sample() : SionnaRTChannelSample
   }

   class SionnaRTChannelSample {

      propagate(Signal) : Signal
   }

   SionnaRTChannel --o SionnaRTChannelRealization : realize()
   SionnaRTChannelRealization --o SionnaRTChannelSample : sample()

   click SionnaRTChannel href "#hermespy.channel.sionna_rt_channel.SionnaRTChannel"
   click SionnaRTChannelRealization href "#hermespy.channel.sionna_rt_channel.SionnaRTChannelRealization"
   click SionnaRTChannelSample href "#hermespy.channel.sionna_rt_channel.SionnaRTChannelSample"

The following minimal example outlines how to configure the channel model within the context of a Simulation:

# Initialize two devices to be linked by a channel
simulation = Simulation()
alpha_device = simulation.new_device(
    carrier_frequency=24e9, pose=Transformation.From_Translation(np.array([8.5, 21., 27.])))
beta_device = simulation.new_device(
    carrier_frequency=24e9, pose=Transformation.From_Translation(np.array([45., 90., 1.5])))

# Load the desired scene
scene = rt.load_scene(rt.scene.munich)

# Create a channel between the two devices
channel = SionnaRTChannel(scene=scene, gain=1., seed=42)
simulation.set_channel(alpha_device, beta_device, channel)

# Configure communication link between the two devices
link = SimplexLink()
alpha_device.transmitters.add(link)
beta_device.receivers.add(link)

# Specify the waveform and postprocessing to be used by the link
link.waveform = RRCWaveform(
    symbol_rate=1e8, oversampling_factor=2, num_data_symbols=1000,
    num_preamble_symbols=10, pilot_rate=10)
link.waveform.channel_estimation = SCLeastSquaresChannelEstimation()
link.waveform.channel_equalization = SCZeroForcingChannelEqualization()

class SionnaRTChannel(scene, gain=1.0, seed=None)[source]¶

Bases: Channel[SionnaRTChannelRealization, SionnaRTChannelSample]

Sionna ray-tracing channel.

Refer to SionnaRT Channel for further information.

Parameters:

scene (str) – Path to the scene file.
gain (float) – Linear channel power gain factor. Defaults to 1.0.
seed (int | None) – Seed used to initialize the pseudo-random number generator.

classmethod Deserialize(process)[source]¶

Deserialize an object’s state.

Objects cannot be deserialized directly, instead a Factory must be instructed to carry out the deserialization process.

Parameters:: process (DeserializationProcess) – The current stage of the deserialization process. This object is generated by the Factory and provides an interface to deserialization methods supporting multiple backends.
Return type:: SionnaRTChannel
Returns:: The deserialized object.

_realize()[source]¶

Generate a new channel realzation.

Abstract subroutine of realize. Each Channel is required to implement their own _realize() method.

Returns: A new channel realization.

Return type:: SionnaRTChannelRealization

serialize(process)[source]¶

Serialize this object’s state.

Objects cannot be serialized directly, instead a Factory must be instructed to carry out the serialization process.

Parameters:: process (SerializationProcess) – The current stage of the serialization process. This object is generated by the Factory and provides an interface to serialization methods supporting multiple backends.
Return type:: None

property scene: Scene¶: Scene object used to generate realizations.

class SionnaRTChannelRealization(scene, scene_file, sample_hooks=None, gain=1.0)[source]¶

Bases: ChannelRealization[SionnaRTChannelSample]

Realization of a Sionna RT channel.

Generated by the _realize() routine of SionnaRTChannels.

Parameters:

scene (Scene) – The loaded scene object.
scene_file (str) – Path to the scene file. Required for simple serialization.
sample_hooks (Optional[Set[ChannelSampleHook]]) – Hooks to be called when a new sample is generated.
gain (float) – Linear channel power gain factor. Defaults to 1.0.

classmethod Deserialize(process)[source]¶

Deserialize an object’s state.

Objects cannot be deserialized directly, instead a Factory must be instructed to carry out the deserialization process.

Parameters:: process (DeserializationProcess) – The current stage of the deserialization process. This object is generated by the Factory and provides an interface to deserialization methods supporting multiple backends.
Return type:: SionnaRTChannelRealization
Returns:: The deserialized object.

_sample(state)[source]¶

Sample the channel realization at a given point in time and space.

Abstract subroutine of sample.

Parameters:: state (LinkState) – State of the channel at the time of sampling.
Return type:: SionnaRTChannelSample

Returns: The channel sample at the given point in time.

serialize(process)[source]¶

Serialize this object’s state.

Objects cannot be serialized directly, instead a Factory must be instructed to carry out the serialization process.

Parameters:: process (SerializationProcess) – The current stage of the serialization process. This object is generated by the Factory and provides an interface to serialization methods supporting multiple backends.
Return type:: None

property scene: Scene¶: Sionna scene object used to generate samples.

class SionnaRTChannelSample(paths, gain, state)[source]¶

Bases: ChannelSample

Sample of a Sionna RT channel realization.

Generated by sampling a SionnaRTChannelRealization.

Parameters:

paths (Paths) – Ray-Tracing paths in this sample. Should be generated with _realize of Realization.
gain (float) – Linear channel power factor.
state (LinkState) – State of the channel at the time of sampling.

state(num_samples, max_num_taps, interpolation_mode=InterpolationMode.NEAREST)[source]¶

Generate the discrete channel state information from this channel realization.

Denoted by

\[\mathbf{H}^{(m, \tau)} \in \mathbb{C}^{N_{\mathrm{Rx}} \times N_{\mathrm{Tx}}}\]

within the respective equations.

Parameters:

num_samples (int) – Number of discrete time-domain samples of the chanel state information.
max_num_taps (int) – Maximum number of delay taps considered per discrete time-domain sample.
interpolation_mode (InterpolationMode) – Interpolation behaviour of the channel realization’s delay components with respect to the proagated signal’s sampling rate. If not specified, an integer rounding to the nearest sampling instance will be assumed.

Return type:

ChannelStateInformation

Returns: The channel state information representing this channel realization.

property expected_energy_scale: float¶

Expected linear scaling of a propagated signal’s energy at each receiving antenna.

Required to compute the expected energy of a signal after propagation, and therfore signal-to-noise ratios (SNRs) and signal-to-interference-plus-noise ratios (SINRs).

TODO Current implementation is technically incorrect.

paths: Paths¶