Page 33 - ITU Journal Future and evolving technologies Volume 2 (2021), Issue 6 – Wireless communication systems in beyond 5G era

ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 6

Regarding intelligence and 6G, there are some critical porting a share of knowledge and intertwining between
challenges that have to be addressed in order to realise different kinds of intelligence. Semantic communications
the vision of intelligent automation. We agree with [69] will remodel wireless communications from connected
that issues related to training, correct evaluation of per‐ things to connected intelligences.
formance and set up of a lower bound for the AI KPI are
hard goals because of both the complexity of a communi‐ 5.7 Quantum and molecular communications
cation network ecosystem like 6G and the lack of expli‐
cability of AI processes and results. Moreover, we also
Some very preliminary applications of quantum and
agree that various ML models and algorithms are hard to
molecular communications may become part of 6G infras‐
be generalised and maybe the future solution we can envi‐
tructure, considering the time‐horizon 2030‐2035 for the
sion will be an intelligent multi‐agent system, where mul‐
irst deployment. The same as it has been for ML and SON
tiple ML algorithms collaborate. On the other hand, we
in 5G, will happen to quantum and molecular communi‐
may disagree with [69] regarding the problem of inter‐ cations, which will actually and extensively be employed
operability since, if 6G will fully realise the complete soft‐
in beyond‐6G communication networks. That will be also
warization of the network and the massive deployment of due to the fact that these very different and novel commu‐
general purpose hardware (started with 5G), the coexis‐
nication paradigms will need a mature and suitable vir‐
tence of various AI modules will be effectively guaranteed tual network infrastructure, which will only come with 6G
by coexistence and ’social’ collaboration of various intel‐ (as mentioned above).
ligent network agents.
5.6 Beyond Shannon with semantic communi‐ ~200 m
cations Quantum Quantum
router router
Until the design of 5G networks, communication has been Classic Local Area Classic Local Area
the basic commodity of every wireless generation. The Network Network
key challenge has been the reduction of the uncertainty
associated to the correct reception of exchanged data,
while targeting higher capacity, reliability, and lower la‐
tency. Such legacy of Shannon’s model has pushed a
never‐stopping race for broader bandwidths, thus explor‐
ing higher frequency bands. Today, kicking‐off research Fig. 13 – Classic local area networks interconnected by quantum routers
and wireless quantum links to realise a quantum campus network.
on future 6G networks, the need for a paradigm shift from
mainstream research, which builds on Shannon’s infor‐ Quantum communications [112] have been discussed for
mation theory, starts taking shape. With 5G, the com‐ decades. While in classic communications the informa‐
munication network has evolved towardsa communicate‐ tion is encoded into bits, in quantum communications,
compute‐control system, laying the foundations for in‐ the information is encoded into the states of a quan‐
tense use of intelligent machines and the rise of new ser‐ tum system (the so‐called wavefunction). In particular,
vices, interconnecting humans and machines possessing if the information is encoded into the spin of a particle,
various degrees of intelligence (either natural or arti i‐ the quantum system is two‐dimensional, and it is called
cial). As recently explained in [88], future services will a qubit. The qubit is an object that stores information
induce to a radical change on the conventional notions of on the unit vector of a two‐dimensional complex vec‐
knowing and learning, guessing and discovering. Knowl‐ tor space. The classic values come from the two stan‐
edge and decisions will become a new commodity of the dard basis vectors. Next, by considering systems com‐
next generation networks and services. The idea is that, posed of multiple correlated qubits (entangled), it is pos‐
whenever communication occurs to convey meaning or sible to see a dependency after measurement, which is
to accomplish a goal, the substantial focus of communi‐ independent of the distance among the various qubits.
cations is on the impact that the received bits have on the The bene its of secure communications through Quan‐
interpretation of the meaning intended by the transmit‐ tum Key Distribution (QKD) and quantum entanglement
ter or on the accomplishment of a common goal. To this are now clearer. In fact, some initial applications of QKD
end, very recent research [88] is exploring the potential will eventually be able to fall into the 6G inal part of
of Semantic and Goal‑Oriented communications to help design and standardization. But, beyond that, there are
to identify the relevant information, i.e. the information other ways to use quantum entanglement for commu‐
strictly necessary to recover the meaning intended by the nication networks. Some examples are synchronisation
transmitter or to accomplish a goal. Thanks to semantic between communication participants (important for se‐
communications, 6G will be able to support new types of cure and ef icient communication protocols), latency‐free
services such as semantic services [88], seamlessly sup‐ processing of data in the communication network dur‐
ing transport or simply higher data rates. Quantum tech‐

© International Telecommunication Union, 2021 21