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The OSI model extended including the Deep Physical Layer; the Deep Physical Layer (DPL) is a further layer placed under the Physical Layer; while the Physical Layer is focused on the 'bits' level, the Deep Physical Layer is focused on the 'electromagnetic field' configurations.
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In this paper a series of concepts concerning the relationships between electromagnetic theory and information transmitted in communication systems using electromagnetic waves are organized in a systematic framework through the introduction of the "Deep Physical Layer" (DPL), a layer placed under the Physical Layer (PL) of the OSI model. While the...
Contexts in source publication
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... consider the OSI (Open Systems Interconnection) model (Fig. 1). The layer closest to the physical characteristics of the communication system is the Physical Layer. This layer is focused on the ability of the system to transmit information in terms of bits in a reliable and effective ...
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... Fixed bemforming antennas, phased arrays, adaptive antennas, SU-MIMO, MU-MIMO, Massive MIMO, as well as Holographica antennas and Intelligent surface antennas are basically radiating systems that optimize the use of the available NDF at the DPL level to reach different goals at the PL level [12]. Now, let us consider the geometry shown in Fig. 11, in which a reflective surface (drawn as a black line and indicated as B) is present. An electromagnetic opaque object, drawn as a grey rectangle, is placed between the source and the receiver, preventing a LOS ...
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... to λ/2 as a transmitting antenna. Each symbol is associated to a (complex) radiation pattern. Consequently, the TX antenna radiates a field that is the interference of three different radiated field configurations (one for each subscriber). As first step, let us consider the standard Zero-Forcing solution adopted in Massive MIMO synthesis. In Fig. 14 the (total) radiated pattern is drawn for all the possible combinations of the QPSK symbols transmitted toward the three subscribers. We can note that the sidelobe level does not meet the requirement outside the (−45 • , 45 • ) angular region. Now, let us consider the synthesis process proposed in [6], based on the theory summarized in ...
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... • , 45 • ) angular region. Now, let us consider the synthesis process proposed in [6], based on the theory summarized in this paper, and slightly modified to handle Massive MIMO (see also Appendix III). The (total) radiated pattern drawn for all the possible combinations of the QPSK symbols transmitted toward the three subscribers is shown in Fig. 15. In terms of communication parameters, the solution causes a loss in the power received by the three users equal to 0.01 dB, 0.01 dB and 0.05 dB compared to the Zero Forcing, while the SIR is respectively 36.5 dB 48.0 dB and 38.2 dB, confirming the underuse of the available spatial degrees of freedom in standard mMIMO ...
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... the problem discussed is the following. Suppose an "innocent" antenna transmits a stream of bits using BPSK constellation. We want to replace the "innocent" antenna with a different antenna that can transmit secret messages to an authorized receiver without anyone outside the direction of the authorized receiver noticing anything suspicious (see Fig. 16). The problem is conceptually close to the grille cipher, in which a pierced sheet, placed on an "innocent" cover text, is used to select the letters of the message hidden by the cover ...
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... strategy adopted in this paper to obtain a steganographic system is based on the identification of a set of four field configurations that are distinguishable on Ω a but collapse into only two distinguishable field configurations on Ω h . (see Fig. 17). Accordingly, communication at the DPL involves four different field ...
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... Fig. 18 the amplitude (upper figure) and the phase (lower figure) of the y 1 pattern is plotted. In the same figure the two vertical green bars show the φ = 18 o angular range ouside which the Ω h domain is positioned. The y 2 pattern (amplitude upper figure and phase lower figure) is plotted in Fig. 19. The two patterns y 1 and y 2 are ...
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... Fig. 18 the amplitude (upper figure) and the phase (lower figure) of the y 1 pattern is plotted. In the same figure the two vertical green bars show the φ = 18 o angular range ouside which the Ω h domain is positioned. The y 2 pattern (amplitude upper figure and phase lower figure) is plotted in Fig. 19. The two patterns y 1 and y 2 are indistinguishable for a receiver placed in Ω h . We can use the two solutions y 1 and y 2 to obtain the four field configurations required at the DPL. In particular, at the VOLUME 4, 2016 DPL the four cases are encoded in the following four field configurations: 1) case 1: y 1 ; 2) case 2: −y 1 ; 3) ...
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... the above definition, we have that a set of points are distinguishable in presence of an level of uncertainty if they belong to a 2 distinguishable set. Consequently, the maximum amount of information identifiable reliably in a set A at an level of uncertainty is equal to C 2 (see Fig. ...
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... example shown in Fig. 14 considers an equispaced linear array of 31 λ/2 long elements with an inter element distance equal to λ/2 as a transmitting antenna, and three users each of them modelled as a λ/2 long wire antenna as the receiving antenna. Two scattering point objects are placed at (x = 40λ; y = −30λ) and (x = 70λ; y = 50λ) respectively. The far-field ...
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... an inter element distance equal to λ/2 as a transmitting antenna, and three users each of them modelled as a λ/2 long wire antenna as the receiving antenna. Two scattering point objects are placed at (x = 40λ; y = −30λ) and (x = 70λ; y = 50λ) respectively. The far-field sidelobes of the transmitting antenna outside the angular range (−α, α) ( Fig. 13) with α = 45 o are required to be lower than −40 dB as per design specification. The method is a straightforward modification of the procedure introduced in [6] in case of SU-MIMO synthesis with pattern ...
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Citations
... The physically-consistent EM information theory should be established by considering the general spatial-temporal-domain signals. Even though the slight asymmetry between information in the temporal-domain and in the spatial-domain is retained [357]. Specifically, the capacity of communications could be improved with an increase of the observation time, which is similar in the spatialdomain by enlarging the size of HMIMO surfaces. ...
p>Future wireless systems are envisioned to create an endogenously holography-capable, intelligent, and programmable radio propagation environment, that will offer unprecedented capabilities for high spectral and energy efficiency, low latency, and massive connectivity. A potential and promising technology for supporting the expected extreme requirements of the sixth-generation (6G) communication systems is the concept of the holographic multiple-input multiple-output (HMIMO), which will actualize holographic radios with reasonable power consumption and fabrication cost. The HMIMO is facilitated by ultra-thin, extremely large, and nearly continuous surfaces that incorporate reconfigurable and sub-wavelength-spaced antennas and/or metamaterials. Such surfaces comprising dense electromagnetic (EM) excited elements are capable of recording and manipulating impinging fields with utmost flexibility and precision, as well as with reduced cost and power consumption, thereby shaping arbitrary-intended EM waves with high energy efficiency. The powerful EM processing capability of HMIMO opens up the possibility of wireless communications of holographic imaging level, paving the way for signal processing techniques realized in the EM-domain, possibly in conjunction with their digital-domain counterparts. However, in spite of the significant potential, the studies on HMIMO communications are still at an initial stage, its fundamental limits remain to be unveiled, and a certain number of critical technical challenges need to be addressed. In this survey, we present a comprehensive overview of the latest advances in the HMIMO communications paradigm, with a special focus on their physical aspects, their theoretical foundations, as well as the enabling technologies for HMIMO systems. We also compare the HMIMO with existing multi-antenna technologies, especially the massive MIMO, present various promising synergies of HMIMO with current and future candidate technologies, and provide an extensive list of research challenges and open directions for future HMIMO-empowered wireless applications.</p
... More recently, it has been noticed that it could be possible to code independent information into the "spatial" variation of the fields by means of Multiple Input Multiple Output (MIMO) systems and related techniques. In particular, Multi-User MIMO (MU-MIMO) systems have opened new perspectives in the communications industry [2,3], since these kinds of systems have transformed the multipath property of a complex propagation environment into a resource that could be exploited to transfer a huge amount of information effectively. ...
The capability of controlling and modifying wireless propagation channels is one of the prerogatives of beyond-5G systems. In this paper, we propose the use of a controllable local propagation environment surrounding the terminals, and analyze its positive effect on the multiplexing capability of massive MIMO systems. In particular, we focus on using a few switched passive elements surrounding each terminal. In this way, the modification of the propagation environment is not realized by means of a single structure, as in reconfigurable intelligent surfaces (RIS), but is achieved by the cooperative work of all the terminals. By employing numerical simulations, we show that the proposed system outperforms its non-reconfigurable counterpart in terms of the number of contemporary connected users. Moreover, the optimized system enables a substantial increase in the minimum received power by the terminals, thus guaranteeing superior channel fairness.
... In order to address these limitations, it is useful to introduce an additional layer below the Physical Layer (PL) in the OSI model. This new layer, called the Deep Physical Layer (DPL, see Fig. 2), is discussed in detail in [22]. Unlike the PL, where information is a "mathematical" quantity based on the Shannon information entropy, the DPL considers information in relation to the physics of the medium carrying the information. ...
... In this context, antennas serve as information transmission systems, whose synthesis should take into account not only conventional objectives like controlling the power density distribution but also communication-specific objectives such as channel capacity maximization. While antenna synthesis in the context of DPL has been addressed in other works [16], [22], [23], this article will not delve into this topic. ...
... This paper does not offer any specific technological solutions for EPDs, but instead provides a high-level analysis of electromagnetic field processing. Therefore, similar to [22], this paper presents a framework for examining and comprehending electromagnetic field processing at a fundamental level, prior to introducing the specific details of the EPD used in the elaboration. This enables a "bird's eye view" of the field elaboration process. ...
The objective of this paper is to examine the processing of the electromagnetic field in the physical communication channel of wireless systems using the concept of the "Deep Physical Layer" (DPL), a layer that is positioned below the Physical Layer of the OSI model. The article delves into the fundamental concept of DPL and presents several numerical findings on devices that can process the field directly in the DPL. These devices are called Electromagnetic field Processing Devices (EPDs) and consist of reflective elements that are extensively distributed in space. They can intelligently modify the spatial configuration of the electromagnetic field to achieve efficient processing. The study reveals that EPDs offer the potential to encode a massive amount of information in the spatial domain. Additionally, the results suggest that quantum computers are an indispensable technology to gain unrestricted access to the large resources that utilizing EPDs in the DPL can unlock. To fully utilize this vast resource necessitates addressing the challenge of searching an unstructured database, which poses a difficulty for classical computers. However, this problem can be efficiently solved by quantum computers using Grover’s algorithm.
... Moreover, a general EM information theory should be established by considering both time domain and spatial domain signals. Specifically, there is a slight asymmetry between information in time domain and in spatial domain [320]. In time domain, the capacity of communications could be improved with an increase of observation time. ...
p>Future wireless systems are envisioned to create an endogenously holography-capable, intelligent, and programmable radio propagation environment, that will offer unprecedented capabilities for high spectral and energy efficiency, low latency, and massive connectivity. A potential and promising technology for supporting the expected extreme requirements of the sixth-generation (6G) communication systems is the concept of the holographic multiple-input multiple-output (MIMO) surface (HMIMOS), which will actualize holographic radios with reasonable power consumption and fabrication cost. An HMIMOS is an ultra-thin and nearly continuous aperture that incorporates reconfigurable and sub-wavelength-spaced antennas and/or metamaterials. Such surfaces comprising dense electromagnetic (EM) excited elements are capable of recording and manipulating impinging fields with utmost flexibility and precision, as well as with reduced cost and power consumption, thereby shaping arbitrary-intended EM waves with high energy efficiency. The powerful EM processing capability of HMIMOS opens up the possibility of wireless communications of holographic imaging level, paving the way for signal processing techniques realized in the EM domain, possibly in conjunction with their digital-domain counterparts. However, in spite of the significant potential, the studies on HMIMOS-based wireless systems are still at an initial stage, its fundamental limits remain to be unveiled, and critical technical challenges with holographic MIMO communications need to be addressed. In this survey, we present a comprehensive overview of the latest advances in the holographic MIMO communications paradigm, with a special focus on their physical aspects, their theoretical foundations, as well as the enabling technologies for HMIMOS systems. We also compare HMIMOS systems with conventional multi-antenna technologies, especially massive MIMO systems, present various promising synergies of HMIMOS with current and future candidate technologies, and provide an extensive list of research challenges and open directions for future HMIMOS-empowered wireless applications.</p
... Moreover, a general EM information theory should be established by considering both time domain and spatial domain signals. Specifically, there is a slight asymmetry between information in time domain and in spatial domain [320]. In time domain, the capacity of communications could be improved with an increase of observation time. ...
p>Future wireless systems are envisioned to create an endogenously holography-capable, intelligent, and programmable radio propagation environment, that will offer unprecedented capabilities for high spectral and energy efficiency, low latency, and massive connectivity. A potential and promising technology for supporting the expected extreme requirements of the sixth-generation (6G) communication systems is the concept of the holographic multiple-input multiple-output (MIMO) surface (HMIMOS), which will actualize holographic radios with reasonable power consumption and fabrication cost. An HMIMOS is an ultra-thin and nearly continuous aperture that incorporates reconfigurable and sub-wavelength-spaced antennas and/or metamaterials. Such surfaces comprising dense electromagnetic (EM) excited elements are capable of recording and manipulating impinging fields with utmost flexibility and precision, as well as with reduced cost and power consumption, thereby shaping arbitrary-intended EM waves with high energy efficiency. The powerful EM processing capability of HMIMOS opens up the possibility of wireless communications of holographic imaging level, paving the way for signal processing techniques realized in the EM domain, possibly in conjunction with their digital-domain counterparts. However, in spite of the significant potential, the studies on HMIMOS-based wireless systems are still at an initial stage, its fundamental limits remain to be unveiled, and critical technical challenges with holographic MIMO communications need to be addressed. In this survey, we present a comprehensive overview of the latest advances in the holographic MIMO communications paradigm, with a special focus on their physical aspects, their theoretical foundations, as well as the enabling technologies for HMIMOS systems. We also compare HMIMOS systems with conventional multi-antenna technologies, especially massive MIMO systems, present various promising synergies of HMIMOS with current and future candidate technologies, and provide an extensive list of research challenges and open directions for future HMIMOS-empowered wireless applications.</p
... Moreover, a general EM information theory should be established by considering both time domain and spatial domain signals. Specifically, there is a slight asymmetry between information in time domain and in spatial domain [320]. In time domain, the capacity of communications could be improved with an increase of observation time. ...
Future wireless systems are envisioned to create an endogenously holography-capable, intelligent, and programmable radio propagation environment, that will offer unprecedented capabilities for high spectral and energy efficiency, low latency, and massive connectivity. A potential and promising technology for supporting the expected extreme requirements of the sixth-generation (6G) communication systems is the holographic multiple-input multiple-output (MIMO) surface (HMIMOS), which will actualize holographic radios with reasonable power consumption and fabrication cost. An HMIMOS is a nearly continuous aperture that incorporates reconfigurable and sub-wavelength-spaced antennas and/or metamaterials. Such surfaces comprising dense electromagnetic (EM) excited elements are capable of recording and manipulating impinging fields with utmost flexibility and precision, as well as with reduced cost and power consumption, thereby shaping arbitrary-intended EM waves with high energy efficiency. The powerful EM processing capability of HMIMOS opens up the possibility of wireless communications of holographic imaging level, paving the way for signal processing techniques realized in the EM domain, possibly in conjunction with their digital-domain counterparts. However, in spite of the significant potential, the studies on HMIMOS-based wireless systems are still at an initial stage. In this survey, we present a comprehensive overview of the latest advances in holographic MIMO communications, with a special focus on their physical aspects, theoretical foundations, and enabling technologies. We also compare HMIMOS systems with conventional multi-antenna technologies, especially massive MIMO systems, present various promising synergies of HMIMOS with current and future candidate technologies, and provide an extensive list of research challenges and open directions.
... As an example, the 5G frame, reported in the paper [1] and regarding a 4 layers (i.e. 4-subchannels SU-MIMO signal [18]), will be analyzed. In the example the scheduler was forced to send all the resources to the user that is placed in the measurement position. ...
5G base stations usually use different beams to transmit broadcast and user data. Moreover the broadcast beam is always "on air", whilst the traffic beam is not. This represents a problem in Maximum Power Extrapolation (MPE) procedures for exposure assessment. In fact, currently adopted measurement approaches are based on the mere observation of phenomena. Recently, a different approach for MPE has been proposed in 1, forcing the traffic toward the measuring position by means of a dedicated User Equipment (UE). Consequently, the measurer loses the "passive" role assumed in the approach usually adopted, and acquires an active role forcing the system under test to assume the most suitable configuration. The use of beam-forcing UEs opens new exciting possibilities, since it makes it possible to take advantage of the UE-specific signals for the estimation for the MPE procedure. The aim of this paper is to explore the potential offered by UE-specific data structures within the MPE considering a real case regarding data acquired on a currently operative 5G base station.
Future wireless systems are envisioned to create an endogenously holography-capable, intelligent, and programmable radio propagation environment, that will offer unprecedented capabilities for high spectral and energy efficiency, low latency, and massive connectivity. A potential and promising technology for supporting the expected extreme requirements of the sixth-generation (6G) communication systems is the concept of the holographic multiple-input multiple-output (HMIMO), which will actualize holographic radios with reasonable power consumption and fabrication cost. The HMIMO is facilitated by ultra-thin, extremely large, and nearly continuous surfaces that incorporate reconfigurable and sub-wavelength-spaced antennas and/or metamaterials. Such surfaces comprising dense electromagnetic (EM) excited elements are capable of recording and manipulating impinging fields with utmost flexibility and precision, as well as with reduced cost and power consumption, thereby shaping arbitrary-intended EM waves with high energy efficiency. The powerful EM processing capability of HMIMO opens up the possibility of wireless communications of holographic imaging level, paving the way for signal processing techniques realized in the EM-domain, possibly in conjunction with their digital-domain counterparts. However, in spite of the significant potential, the studies on HMIMO communications are still at an initial stage, its fundamental limits remain to be unveiled, and a certain number of critical technical challenges need to be addressed. In this survey, we present a comprehensive overview of the latest advances in the HMIMO communications paradigm, with a special focus on their physical aspects, their theoretical foundations, as well as the enabling technologies for HMIMO systems. We also compare the HMIMO with existing multi-antenna technologies, especially the massive MIMO, present various promising synergies of HMIMO with current and future candidate technologies, and provide an extensive list of research challenges and open directions for future HMIMO-empowered wireless applications.
An innovative approach based on an
inverse source (IS)
formulation is introduced for the design of constrained static-passive electromagnetic skins (
SP-EMS
s). By leveraging on the ill-posedness/non-uniqueness of the
IS
problem at hand, a closed-form expression for the synthesis of
SP-EMS
s simultaneously complying with complex wireless coverage requirements and urban installation constraints is deduced. Representative results from a wide set of numerical experiments are reported to prove the effectiveness and the computational efficiency of the proposed method as a suitable tool towards a real and effective implementation of the so-called
Smart Electromagnetic Environment (SEME)
.
The objective of this chapter is a description of the wireless communication process from a physical point of view. The analysis of the communication system is carried out considering an extended version of the OSI stack that includes an additional layer placed below the Physical Layer (PL). In this further layer, called the Deep Physical Layer (DPL), the communication process is analyzed in terms of distinguishable electromagnetic field configurations on the receiving antenna. The DPL contains all the resources potentially available to the telecommunication system in terms of space/time/polarization field configurations, while the PL implements specific solutions to exploit the potential offered by the DPL. Such a potential is limited only by the physical laws, which are inviolable. Consequently, the limits imposed at the level of DPL are absolute. In this sense, the DPL is a more fundamental level than the PL. The numerous solutions proposed for 6G that include intelligent modifications of the propagation environment can be seen as “data processing” at the DPL level in order to preserve information lost in previous generations of communication systems.
