PPGEE Doctoral Thesis Defense Session 47st - Analysis of the Effect of Epidemic Interference in Digital Communications Systems

STUDENT: JOEL EUGÊNIO CORDEIRO JUNIOR

DATE: 12/01/2023

TIME: 14:00

LOCATION: https://us02web.zoom.us/j/87392883963?pwd=Q1UzVFJGWFNnaloxVkF0M2VoZGIzZz09

 

TITLE:

 

Analysis of the Effect of Epidemic Interference on Digital Communications Systems

 

 

KEYWORDS:

 

Epidemic Interference Model; Digital Communications Systems; Gauss-Hermite quadrature

 

 

PAGES: 123

SUMMARY:

 

One of the main problems of cellular mobile communications systems is interference. The growing demand for connectivity can make this problem even more challenging, creating scenarios with a high density of devices and a massive number of connections. Therefore, it is important to investigate and understand different interference models present in wireless communication channels. The Epidemic Interference (IE) model was recently proposed to represent the situation in which many devices start transmitting simultaneously, causing rapid growth in interference levels on a shared channel. Based on this interference model, this thesis presents a study of the effect of IE in digital communications systems in terms of signal synchronization in coherent demodulation, the probability of interruption, the error rates of transmitted symbols and the theoretical capacity of the channel affected by the IE. To evaluate the effect of IE on the synchronization of the received signal, expressions for the theoretical limit of the carrier phase estimation error variance are derived. These expressions are evaluated numerically for cases where the received signal is an unmodulated carrier and a signal with digital phase modulation. The impact of IE is also analyzed using the expressions for interrupt probability and symbol (and bit) error probability, which are derived for amplitude, phase and quadrature digital modulation schemes. Finally, ergodic capacity functions of the channel in the presence of EI are presented. In addition to the numerical expression, approximate analytical expressions for the capacity are proposed. Due to the lognormal distribution of interference power, the expressions presented in this thesis are obtained by Gauss-Hermite quadrature. Computational simulations were carried out to validate the expressions obtained. In the scenarios analyzed, it is observed that the presence of IE increases the phase estimation error, the probability of interruption and the symbol (and bit) error rates. Additionally, IE reduces channel capacity. The partial results also show that the performance of the studied systems depends on both the average IE power and the spread of the interfering power distribution.

 

 

BOARD MEMBERS:

External to the Institution - FABRICIO BRAGA SOARES DE CARVALHO

External to the Institution - RAÍSSA BEZERRA ROCHA

Internal - KARCIUS DAY ROSARIO ASSIS

President - MARCELO SAMPAIO DE ALENCAR - UFPB

External to the Institution - WASLON TERLLIZZIE ARAÚJO LOPES

 

Published on 11/28/2023 

Em 03/12/2023