LoS, Non-LoS and Quasi-LoS Signal Propagation: A Three State Channel Model

Jonathan W. Browning, Simon L. Cotton, Paschalis C. Sofotasios, David Morales-Jimenez, Michel D. Yacoub

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)
66 Downloads (Pure)


The modeling of wireless communications channels is often broken down into two distinct states, defined according to the optical viewpoints of the transmitter (TX) and receiver (RX) antennas, namely line-of-sight (LoS) and non-LoS (NLoS). Movement by the TX, RX, both and/or objects in the surrounding environment means that channel conditions may transition between LoS and NLoS leading to a third state of signal propagation, namely quasi-LoS (QLoS). Unfortunately, this state is largely ignored in the analysis of signal propagation in wireless channels. We therefore propose a new statistical framework that unifies signal propagation for LoS, NLoS, and QLoS channel conditions, leading to the creation of the Three State Model (TSM). The TSM has a strong physical motivation, whereby the signal propagation mechanisms underlying each state are considered to be similar to those responsible for Rician fading. However, in the TSM, the dominant signal component, if present, can be subject to shadowing. To support the use of the TSM, we develop novel formulations for the probability density functions of the in-phase and quadrature components of the complex received signal as well of the received signal envelope. The offered results are corroborated with results from respective computer simulations, whilst it is shown that the proposed model is more versatile than existing conventional models.
Original languageEnglish
Title of host publicationIEEE 95th Vehicular Technology Conference: (VTC2022-Spring): Proceedings
Subtitle of host publicationHelsinki, Finland, June 19-22, 2022.
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages5
Publication statusPublished - 25 Aug 2022

Publication series

Name2022 IEEE 95th Vehicular Technology Conference: Proceedings
ISSN (Print)1090-3038
ISSN (Electronic)2577-2465


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