Page 34 - 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

nologies bring advantages to all kinds of communications Nano-bio-communications can fall into five categories ac-
in ixed networks, cellular mobile communications, and cording to the channel characteristics: Diffusion-based,
even satellites. Quantum communications will realise molecules are immersed in a luid and they freely diffuse;
communication networks quite more secure against hos‐ wired active, molecules move in prede ined microtubules;
tile attacks from the outside. The combination of quan‐ wireless active, using bacteria carrying messages in their
tum computing and quantum communications, towards DNA or using nanorods (e.g. platinum or gold) exploiting
the so‐called quantum Internet, will be an exciting ield of the chemical energy of the environment; physical contact‐
research in this regard but it will be ready for beyond 6G based, communication happens via contacts; Förster res‐
networks. In fact, the pillar of quantum communication onance energy transfer (FRET)‐based employing speci ic
networks is the distribution of entangled systems among molecules called luorophores, which can be excited by
the communicating nodes. However, the distribution is either optical or chemical stimuli. Side by side, another
strongly limited by the attenuation and the coupling, im‐ classi ication of nano‐bio communications is possible ac‐
plying the reduction of quality according to the distance. cording to the way molecules propagate [114]. First,
That is why signi icant effort is devoted to the design and walkway‐based communications follow prede ined paths,
realisation of the so‐called quantum repeaters. Neverthe‐ next low‐based communications release molecules in a
less, quantum repeaters need the theoretical and practi‐ luid and guide them using currents or lows, and inally
cal realisation of reliable quantum memories and error‐ diffusion‐based communications. Even if icant re‐
correcting schemes. These technologies will hardly be search is ongoing to design and develop the irst molec‐
ready for massive deployment and integration into 6G. ular communication to empower eHealth and realising
Because of that, the quantum communication networks intra‐body networks, the paradigm of the Internet of Bio‐
that will be realisable in 6G will be quantum LANs and Nano‐Things [115] is still far from being reality. Fig. 14
quantum campus networks. Fig. 13 depicts a conceptual depicts the combination of molecular and classic commu‐
schematic of a quantum campus network. Classic LANs nication technologies, for example, in industrial scenar‐
(and also classic‐quantum LANs) are equipped with quan‐ ios and agriculture. Various nano‐nodes emit molecular‐
tum routers, responsible for creating and distributing en‐ based signals via diffusion to a nano‐router, which can for‐
tanglement among the quantum nodes. If these routers ward the information. As an example, this can be a pos‐
communicate wirelessly, they require telescopes to reveal sible use case of monitoring speci ic conditions in chem‐
the photons. ical industry. Next, nano‐routers can also be gateways
and aggregation points for then being able to convert the
Side by side, another important emerging communica‐ molecular signals into classic ones. By equipping these
tion paradigm refers to nano‐scale and molecular com‐ gateways with classic wireless interfaces, the information
munications [113]. Instead of using electromagnetic sent by molecules can be transmitted through longer dis‐
waves, in molecular communications, the information is tances, for example in industrial campus networks or via
mainly sent via the diffusion of molecules through a spe‐ the Internet. As it has just been said for quantum com‐
ic channel. Additionally, ic molecules can be munications, we believe that the technical issues, and the
employed to carry chemo‐signals or instead molecular ethics problems involved within biomolecular communi‐
structures containing information. In this way, molec‐ cations, will make molecular communications available
ular carriers can set up multiple independent channels for networks beyond 6G.
using the same medium. If molecules are biological,
these communications are labelled ’nano‐bio’. Nano‐bio‐
communications are the main technology to realise intra‐ 6. CONCLUSION
body networks.
This article started describing the main characteristics of
L TE wireless cellular networks in parallel to the emerging
softwarization and computing paradigms, that were caus‐
Nano Nano ing the inherent change of wireless networks towards the
Router/ Router/ advent of 5G. Next, the critical presentation of 5G archi‐
Gateway Gateway
Molecules Molecules tectural characteristics, KPI, use cases, and standardised
technologies was important to show and to motivate in
detail what applications and services will lead to 6G com‐
Nano Nano munication networks. For this purpose, the article sur‐
node Nano node Nano veyed the research trends in the literature about 6G, in or‐
node node
der to understand what the 6G system requirements, KPI,
innovative architectures and applications will be. The i‐
Fig. 14 – Hybrid scenario, in which molecular communications via dif‐ nal part of this work critically discussed the main aspects
fusion are combined with usual wireless communication technologies. of 6G in the authors’ vision, in respect of what the litera‐
ture has been proposing and what 5G has become in the
current standardization phase.

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