Page 149 - ITU Journal, Future and evolving technologies - Volume 1 (2020), Issue 1, Inaugural issue

ITU Journal on Future and Evolving Technologies, Volume 1 (2020), Issue 1

vironment from sensed data. A lexible communications It is also possible to bene it from Wireless Power Trans-
system needs to bene it from the advantages of popular fer (WPT) while designing zero-energy IoT systems [139].
ML approaches such as reinforcement learning, deep Under the WPT concept, Simultaneous Wireless Informa-
learning, and edge computing [37, 48, 69, 73]. Especially tion and Power Transfer (SWIPT) is the most popular
distributed intelligence (edge AI) with edge computing technology that may be a candidate for 6G networks [60,
is a promising paradigm for 6G communications [36]. 140]. SWIPT designs are also used for interference ex-
The management of multi-band utilization, MAC layer ploitation purposes [141] since interference can be use-
control, heterogeneous and cell-less networks, and the ful for energy harvesting. Transformation of interference
ISAC systems cannot be done in an all centralized man- into an energy source introduces another lexibility per-
ner. Edge computing will play an important role at that spective.
point with the help of distributed intelligence so 6G big
data can be processed at the edge nodes without being
collected at a centralized network.
3.7 Secure Communications
Intelligent networks are not limited to AI-aided concepts.
For example, RIS technology is one of the most popular
research topics nowadays [133,134]. Intelligent surfaces With applications such as eHealth, online banking, and
bring a new lexibility on the control of channel parame- autonomous driving etc., wireless communications
ters [57]. In the past, a wireless channel was just an ob- promises to be an enabler of innumerable sensitive ap-
servable medium. However, it can be controlled at some plications utilizing private data. However, the broadcast
level with new generation wireless systems. Interference nature of wireless communications makes it vulnerable
management lexibility is increased by controlling capa- to several security threats such as eavesdropping, imper-
bilities of the wireless channel. These lexibility aspects sonation, and jamming. In order to ensure security of
also affect the technology designs in different communi- such applications, PHY Layer Security (PLS) is an emerg-
cations layers [66, 71]. To exemplify, having a control ca- ing solution that has the capability to complement the
pability in multipath propagation, such as controlling de- conventional cryptography-based security techniques. In
lay spread, Doppler spread and the number of multipath fact, PLS is more suited for the increased heterogeneity
alleviates the constraints related to waveform design. RIS and power/processing restrictions of future wireless
technology can also be considered as passive holographic networks since it exploits the characteristics of the wire-
MIMO surfaces if it is located closer to the transmitter and less channel and PHY properties associated with the link
receiver antennas [53]. Additionally, it is possible to em- such as noise, fading, interference, and diversity [142].
ploy holographic MIMO surfaces as active elements. The It is also possible to increase this lexibility by designing
active holographic MIMO surfaces work similar to mas- cross-layer security algorithms with the PHY and MAC
sive MIMO but their softwarization lexibility is higher layer [143]. In several 6G papers, secure communications
than the conventional MIMO systems [53]. is discussed as one of the main topics [8,35,44,81]. PHY
and cross-layer security concepts are expected to play a
3.6 Green Communications critical role in 6G networks because of their capability
to support joint design of security, reliability, and latency.
While candidate 6G key enablers are increasing the lex-
ibility in different domains, new architectural changes
of 6G should support energy ef iciency and green com-
munications [43, 64, 70]. Zero-energy Internet of Things As discussed in the previous subsections, ISAC and REM
(IoT) is one of the most important concepts since ultra concepts will be important enablers in 6G communica-
low-power wireless communications is necessary for 6G tions. However, a new security problem arises since there
connectivity [51]. In this context, Radio Frequency (RF) may be a large amount of con idential data for ISAC and
energy harvesting is studied with ambient backscatter REM concepts. In the literature, this problem is treated
technology for 6G communications [135, 136]. Thus, in [144] for ISAC security, and in [145] for REM security.
low-power wireless systems can obtain their energy from Thus, there is a need for more secure communications op-
the available high-power radio waves. Backscatter com- tions in 6G networks to meet new types of security re-
munications enables energy harvesting, simplifying the quirements, especially for ISAC and REM concepts. More-
implementation of zero-energy IoT designs. Provision over, in order to tackle spoo ing attacks, authentication at
of rich options for energy-ef iciency promises ful ilment the physical layer by using features of channel and hard-
of energy requirement variations belonging to different ware impairments can also provide a fast, lightweight,
applications. Within this direction, the Symbiotic Ra- and ef icient alternative for crypto-security for authen-
dio (SR) concept offers highly reliable backscattering tication in future wireless networks. Furthermore, the
communications together with mutualism spectrum physical layer solution will also provide ef icient robust-
sharing [137,138]. ness against jamming attacks using terrestrial and lying
relay and other new multi-antenna-based solution.

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