Introduction

Path loss calculations are carried out between a transmitter and a receiver using propagation models and other calculations related to radio wave propagation such as shadowing and fading. Propagation models are mathematical representations of the average loss in signal strength over distance. Shadowing and fading margins are added to this average loss to get more precise path loss values.

NetSim is a packet level network simulator, for answering questions such as: application throughputs, packet latencies, probability of packet delivery, rate of packet delivery, etc. For such a simulation it is sufficient and efficient to model the power attenuation over a channel. Sufficient, because the received power determines the probability of packet reception. Efficient, because a symbol-by-symbol model would require a channel model with a complex response function, and modelling of all the propagation paths; this will make the simulation very slow, defeating the very objective of packet-level modelling. Questions such as file transfer throughput, voice and video quality, the effect of network sizing, the comparisons between different wireless access technologies can all be answered by a packet level model, along with power loss models over the communication channels.

Propagation models are used to model power loss (signal attenuation) for all wireless links. These include WLAN – 802.11, Legacy Networks, ZigBee / IOT / WSN – 802.15.4, LTE, Cognitive radio – 802.22 and VANET. The 5G NR propagation models are described in the 5G NR technology library document.

Propagation Loss

The three different and mutually independent propagation phenomena influence the power of the received signal are (a) path loss, (b) shadowing, and (c) fading. The different models available in NetSim are:

  1. Path loss Models

    1. Free Space Propagation (Default option in GUI)

    2. Log Distance

    3. HATA Suburban

    4. HATA Urban

    5. COST 231 HATA Suburban

    6. COST 231 HATA Urban

    7. Indoor Office

    8. Indoor Factory

    9. Indoor Home

    10. No Path Loss

    11. Two Ray

    12. Range Based

    13. Patloss Matrix File

    14. None

  2. Shadowing Models

    1. None

    2. Constant

    3. Lognormal

  3. Fading Models

    1. None

    2. Rayleigh

    3. Nakagami

    4. Rician