StochasticChannelModel Class Reference¶

The full PHY link model: everything between a transmitted air frame and the decision on whether it was received.

The impairments are modeled statistically – drawn from the distributions of a 3GPP propagation study, rather than computed from the geometry of an actual environment – which is what the name refers to, and what sets this model apart from IdealChannelModel, its impairment-free sibling. It is far more than propagation, and covers:

• path loss per deployment scenario, LOS/NLOS state, and log-normal shadowing;
• multipath fading, Jakes or Rayleigh;
• the antenna pattern attenuation and the link budget (antenna gains, cable loss, noise figures, thermal noise);
• interference from other cells – downlink, uplink, external cells and background cells;
• the assembly of all of the above into a per-band SINR, and the mapping of that SINR onto a block error probability (with HARQ reduction) that decides reception;
• the per-node mobility state the correlated quantities need: position history, speed, and the point at which shadowing and LOS were last drawn;
• the SINR statistics.

The propagation formulas proper live in a PathLossModel strategy (pathLoss_) that this class owns and delegates to from computePathLoss, computeLosProbability, computeShadowing and computeAngularAttenuation. Which 3GPP propagation study the strategy implements is chosen by the pathLossType parameter ("Tr36814", "Tr36873" or "Tr38901"); createPathLossModel() instantiates the matching strategy class. Tr36873ChannelModel and Tr38901ChannelModel are NED-level presets of this class (no C++ class of their own) that only override the pathLossType default, to Tr36873 and Tr38901 respectively. All the rest – fading, interference, SINR assembly, the reception decision – is shared by every pathLossType.

Supported propagation studies:

• 3GPP TR 36.814, "Further advancements for E-UTRA physical layer aspects", v9.2.0, March 2017
• 3GPP TR 36.873, "Study on 3D channel model for LTE", v12.7.0, December 2017
• 3GPP TR 38.901, "Study on channel model for frequencies from 0.5 to 100 GHz", v16.1.0, December 2019
• 3GPP TS 36.211, "LTE; Physical channels and modulation", v13.2.0, June 2016

covering the Indoor Hotspot (InH), Urban Microcell (UMi), Urban Macrocell (UMa), Rural Macrocell (RMa) and Suburban Macrocell (SMa) deployment scenarios (not every study covers every scenario; see the PathLossModel subclasses).

D2D links are not evaluated here. The D2dChannelModel subclass layers them on top of this class.