IEEE Systems, Man and Cybernetics Magazine - October 2021 - 19

occurrence, modeling, and distribution is observed and
answered at the data link layer [8]. Channel error models are
dynamical systems: they have a time evolution and outputs in
the form of discrete time series, but are they chaotic? Can a
model based on chaotic systems encompass the dynamics of
channel errors?
The subtle problem of modeling is bringing in all of
the existing elements of the real system into the model
while keeping out all of the nonexisting ones. A certain
dynamical system model that happens to be chaotic may
represent certain statistical properties of the real system
well. However, if the original system is not chaotic, the
model is bringing a lot of rich, but unwanted, properties
of its own.
The channel errors are an example of a discrete time
system, but the processes we describe at this layer
could be inherently a combination of both continuous
and discrete time modes. This is the case of a discrete
system interacting with a continuous one, one being
embedded within the other. Medium access control
(MAC) for wireless networks can be modeled as such a
system [9] (Table 1).
Self-Similar Traffic Across the Layers
The characteristics of the traffic in (wireless) networks
have been investigated for years from the perspective of
signal processing, statistics, and linear as well as nonlinear
signal theory. The identification of statistical properties
and nonlinear model parameters of both wireless local
area network (LAN) and IP traffic would enable better
models and, therefore, better control, prediction, caching,
and routing.
An elementary question is that of memory: is the time
series of the wireless LAN traffic showing any long-range
dependence over time, or it is just coin tossing at every
time instant? The same question was raised at the network
layer for the IP traffic, observing the TCP congestion
control. The rise and fall of the Nile, a celebrated
example of complex patterns in nature, is an example of
a system's memory.
In the study of the Nile, Hurst introduced the notion of
the Hurst exponent as a measure of long-term dependence
in data. It was not too surprising when the Hurst exponents
were found to be directly related the fractal dimension
of self-similar data, as the memory of the system
described by the Hurst exponent affects the smoothness of
a signal and fractal scale.
The wireless LAN traffic was expected to be self-similar:
in the mid 1990s, self-similarity in Ethernet traffic was
detected, and the research community had a field day in
wireless traffic. The packets, bursts, round-trip time, and
errors-self-similarity appeared to be everywhere. A contributing

IEEE Systems, Man and Cybernetics Magazine - October 2021

Table of Contents for the Digital Edition of IEEE Systems, Man and Cybernetics Magazine - October 2021

Contents
IEEE Systems, Man and Cybernetics Magazine - October 2021 - Cover1
IEEE Systems, Man and Cybernetics Magazine - October 2021 - Cover2
IEEE Systems, Man and Cybernetics Magazine - October 2021 - Contents
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 2
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 3
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 4
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 5
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 6
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 7
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 8
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 9
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 10
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 11
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 12
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 13
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 14
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 15
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 16
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 17
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 18
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 19
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 20
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 21
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 22
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 23
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 24
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 25
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 26
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 27
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 28
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 29
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 30
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 31
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 32
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 33
IEEE Systems, Man and Cybernetics Magazine - October 2021 - 34
IEEE Systems, Man and Cybernetics Magazine - October 2021 - Cover3
IEEE Systems, Man and Cybernetics Magazine - October 2021 - Cover4
https://www.nxtbook.com/nxtbooks/ieee/smc_202110
https://www.nxtbook.com/nxtbooks/ieee/smc_202107
https://www.nxtbook.com/nxtbooks/ieee/smc_202104
https://www.nxtbook.com/nxtbooks/ieee/smc_202101
https://www.nxtbook.com/nxtbooks/ieee/smc_202010
https://www.nxtbook.com/nxtbooks/ieee/smc_202007
https://www.nxtbook.com/nxtbooks/ieee/smc_202004
https://www.nxtbook.com/nxtbooks/ieee/smc_202001
https://www.nxtbook.com/nxtbooks/ieee/smc_201910
https://www.nxtbook.com/nxtbooks/ieee/smc_201907
https://www.nxtbook.com/nxtbooks/ieee/smc_201904
https://www.nxtbook.com/nxtbooks/ieee/smc_201901
https://www.nxtbook.com/nxtbooks/ieee/smc_201810
https://www.nxtbook.com/nxtbooks/ieee/smc_201807
https://www.nxtbook.com/nxtbooks/ieee/smc_201804
https://www.nxtbook.com/nxtbooks/ieee/smc_201801
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_1017
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0717
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0417
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0117
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_1016
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0716
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0416
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0116
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_1015
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0715
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0415
https://www.nxtbook.com/nxtbooks/ieee/systems_man_cybernetics_0115
https://www.nxtbookmedia.com