COMMUNICATION CHANNEL, DEVICE, AND PROCESS SET FOR MULTI-CHANNEL COMMUNICATION - Patent application

Abstract

The present invention provides an assembly of communication channels comprising a plurality of first channels (ch11, ch12) at the same carrier frequency, the assembly comprising at least one first carrier electromagnetic wave (W1) (hereinafter referred to as carrier wave) carrying an orbital angular momentum (OAM) whose phase is twisted around a predetermined twist axis (D), characterized by an orbital angular momentum (OAM1) (for short referred to as OAM), the wavefront of which is divided in space into mutually distinct sectors (S1...Sp), each of which is characterized by the orbital angular momentum (OAM1) of the first wave (W1) and by one of the sectors (S1...Sp) of the first wave (W1), in which the wave is modulated differently from the other sectors.

Description

[Technical Field]

[0001] The present invention relates to a set of communication channels, an apparatus and a process for multi-channel communication.

[0002] The present invention relates to both analog and digital communications.

[0003] The communication is at least transmission and reception, but does not exclude two-way communication.

[0004] The invention is particularly relevant to the field of wireless transmission (eg radio), but does not exclude other types of transmission.

[0005] The present invention relates to both single-user transmission and multi-user communication. [Background technology]

[0006] In the communications field, there is always a pressing need for increased data transfer capacity.

[0007] Generally, wireless communication channels are known as electromagnetic waves with different frequencies, each of which is defined as a channel.

[0008] Professor Fabrizio Tamburini, one of the inventors of the present invention, has previously experimented with the possibility of transmitting several channels on the same frequency.

[0009] The experiment took place in St. Mark's Square in Venice on June 24, 2011, and is therefore known as the "San Marco" experiment.

[0010] During the experiment, normal electromagnetic waves are transmitted simultaneously with torsional electromagnetic waves (i.e., carrying orbital angular momentum (also called OAM)), both of which are transmitted at the same frequency and modulated to carry the same information (a video signal).

[0011] It was discovered that the waves remained detectable and it was possible to switch from receiving one to receiving the other, and vice versa. Thus, it was concluded that each could define an independent communication channel at the same frequency. This obviously serves the primary purpose of increasing data transfer capacity at the same frequency, and possibly even multi-user purposes, utilizing one channel per user.

[0012] In addition to the problem of increasing data transmission channels, there is also the pressing problem of limiting or eliminating the phenomenon of uncontrollable interference, ensuring the quality of the data transmitted.

[0013] Following the San Marco experiments, the inventors continued their research with the goal of further increasing the number of channels suitable for transporting data at high-quality standards.

[0014] It is an object of the present invention to overcome all or some of the problems of the known art.

[0015] In particular, a preferred object of the present invention is to enable high quality multi-channel data transmission.

[0016] A preferred object of the present invention is to define multiple channels at the same frequency, each with high transmission quality.

[0017] Yet another and more preferred object is to define a plurality of transmission channels that can be used for transmission under intentionally disrupted conditions (commonly referred to as jamming conditions) for protection purposes.

[0018] Another and more preferred object is to define a data transmission that is easily and clearly distinguishable by a given receiver within the scope of communications that have been intentionally disrupted for protection purposes (jamming conditions). Summary of the Invention

[0019] The object is achieved by the invention as defined in the appended claims, which are incorporated as an integral part of this description.

[0020] Specifically, according to its first general aspect, the invention relates to a set of communication channels comprising a plurality of first channels (CH11, CH12) at the same carrier frequency, the set comprising at least one first carrier electromagnetic wave (W1) carrying an Orbital Angular Momentum (OAM), i.e. the phase is twisted around a predetermined direction in space, the first carrier electromagnetic wave (W1) being characterized by an Orbital Angular Momentum (OAM1) (for simplicity, OAM), the wavefront of said wave being divided in space into mutually different propagation sectors (S1...Sp), each of said first channels being the orbital angular momentum (OAM1) of the first wave (W1); one of the sectors (S1...Sp) of the first wave (W1), the wave being modulated differently from the other sectors; It is characterized by:

[0021] It should be noted that for the purposes of the present invention, the carrier frequency of a channel is always considered to be the same, even if the wave is frequency modulated within a predetermined bandwidth. In other words, the carrier frequency of a channel has a predetermined frequency modulation tolerance given by the predetermined bandwidth.

[0022] According to a second aspect, the present invention relates to a multi-channel communication device comprising at least one wireless transmission device (2, 102) (hereinafter, for short, referred to as Tx) and a wireless reception device (3, 103) (hereinafter, for short, referred to as Rx), The Tx transmission device (2, 102) - a plurality of transmitting antennas (T1-Tn); a plurality of modulation sections (S1-Sp) each defined by a group of said antennas operatively associated with one another; - driving means (10) configured to drive said T1-Tn antennas to generate at least one carrier electromagnetic wave (W1), the phase of which is twisted around a predetermined direction in space, the carrier electromagnetic wave (W1) being characterized by an orbital angular momentum (OAM1) and a carrier frequency; - modulation means (11) operatively associated with said sections (S1-Sp) for modulating corresponding sectors of the wavefront of said electromagnetic wave (W1) with orbital angular momentum (OAM), the modulations of the sectors being independent of one another and defining respective channels (Ch11, Ch12, Ch21, Ch22) at the same carrier frequency; It is characterized by the fact that it has

[0023] According to a third aspect, the present invention relates to a multi-channel communication process, namely, the multi-channel communication process comprises the following steps: - generating at least one carrier electromagnetic wave (W1) carrying orbital angular momentum (OAM), i.e., the phase is twisted in a predetermined direction in space, the carrier electromagnetic wave (W1) being characterized by the orbital angular momentum (OAM1) and the carrier frequency; - dividing the wavefront into independently modulated sectors (S1-Sp) and considering each one as a transmission channel (Chx,x) at that carrier frequency; receiving a wavefront and determining the channel; Includes:

[0024] Further features and advantages of the present invention will be best seen in the following detailed description of preferred applications thereof, given by way of example and not by way of limitation, with reference to the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0025] [Figure 1] 1 shows a schematic representation of a communication device according to the invention and a first communication channel defined according to the invention; [Figure 2]1 shows a communication device according to the invention with a different arrangement of the antennas compared to the device of FIG. 1, which is seen in a plane perpendicular to the direction of propagation and which highlights the first channel. [Figure 3] The apparatus of Figure 2 is shown schematically in perspective view, highlighting the division of sections into wireless transmission devices. [Figure 4] 4 shows sectors of the cylindrical wavefront of the torsional electromagnetic wave of FIGS. 2 and 3 subdivided by sections of a wireless transmission device. [Figure 5] 2 shows a first channel and a second channel according to the present invention, produced by the same device as in FIG. 1; [Figure 6] 5 shows a first channel and a second channel according to the present invention, produced by the same apparatus as in FIGS. [Figure 7] 7 shows a sector of the cylindrical wavefront of a torsional electromagnetic wave generated by the device of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0026] Referring to FIG. 1, there is shown a first wireless communication device, generally designated 1, according to the present invention.

[0027] The apparatus comprises at least one wireless transmitting device 2 (hereinafter, for short, referred to as Tx) and at least one wireless receiving device 3 (hereinafter, for short, referred to as Rx).

[0028] The device 1 defines a set of communication channels between Rx and Tx that are common and have the same frequency, and the fact that they are defined by electromagnetic waves at a carrier frequency with a phase twisted around a predetermined direction in space (hereinafter referred to as twisted waves or carrier waves for short).

[0029] FIG. 1 specifically shows a plurality of first communication channels Ch1,1 and Ch1,2, which have in common: - the same carrier electromagnetic wave W1, the angular momentum OAM1 of the wave W1; It has.

[0030] The channels are different from one another in that they correspond respectively to respective sectors S1-Sp of the wavefront of the twisted carrier electromagnetic wave W1.

[0031] In each sector, the wave W1 is modulated differently from the other sectors, preferably by at least one of the following: phase, amplitude, polarization, frequency, path diversity, and other methods known in the art.

[0032] Frequency modulation is intended as modulation of a carrier frequency within a predetermined bandwidth, in which case, for purposes of the present invention, the corresponding channel is considered a carrier frequency channel. Generally, the carrier frequency is preferably on the order of MHz, while the modulation bandwidth is on the order of KHz. For example, for a carrier frequency of 88.8 MHz, the modulation bandwidth may be + / - 100 KHz.

[0033] In general, the bandwidth is therefore preferably a fraction of the frequency of the carrier wave (or, in technical terms, the "carrier").

[0034] A channel is centered around a carrier frequency, for example, the one an FM radio "tunes" to. Frequency modulation does not appreciably change the OAM, and phase modulation (such as digital multiplexing (MUX) such as PSK, QPSK, QAM, etc., such as digital TV MUX) is a small phase variation (controlled ripple) in the bridge azimuth phase typical of each of the OAM states. Each channel in a chosen OAM state acts as a "phase carrier" on a channel characterized by its carrier frequency.

[0035] Thus, in summary, it is possible to perform frequency modulation on the carrier frequency and phase modulation on the carrier phase shape characteristics of each OAM state. Each OAM state obviously has its own phase signature, such as a one-layer spiral, OAM1=+1 if left-handed, or OAM1=-1 if right-handed, or two or more layers of spirals, ideally up to an infinite layer spiral. A non-limiting metaphorical example is the fusilli shape, i.e., the well-known pasta shape.

[0036] Tx transmission devices generally include: a plurality of T1-Tn transmit antennas; - a plurality of modulation sections (S1-Sp), each defined by a group of antennas operatively associated with one another; - driving means 10 configured to drive said T1-Tn antennas to generate at least one electromagnetic wave, preferably a plurality of electromagnetic waves (W1-Wk), each with a desired and distinct Orbital Angular Momentum (OAM) for each wave; - modulation means 11 operatively associated with said sections (S1-Sp) for modulating corresponding sectors of the wavefront of said electromagnetic wave with orbital angular momentum (OAM), the modulation of the sectors being independent of each other; Includes:

[0037] In this way, every single electromagnetic wave with OAM is used as the main signal carrier, and each sector of each of these waves corresponds to a channel.

[0038] Preferably, the driving means 10 modulates at least one of the following: amplitude, frequency, path diversity and phase.

[0039] Preferably, the modulation means 11 modulates at least one of the following: amplitude, frequency, path diversity and phase.

[0040] A practical metaphor might be compared to the well-known shape of pasta. Hypothetically, imagine the spatial structure of the OAM "carrier" as, say, fusilli (the well-known screw shape of pasta). We can imagine each fusilli associated with an OAM channel as having lines or small undulations that do not significantly alter its main flap structure; that is, they always retain the shape of a fusilli. To have an OAM channel, we need fusilli with a number of flaps equal to the L value of the OAM. Therefore, we need to maintain that structure; various modulations merely add small structures on top of the main fusilli structure. Modulations in phase can be thought of as fusilli grooves, and modulations in amplitude as variations in fusilli size; in either case, they preserve the average topology of the OAM phase structure.

[0041] Figure 1 shows an example of a single torsional electromagnetic wave W1, whose corresponding wavefront S1-Sp sectors define equal numbers of channels Ch1,1 (W1 / OAM1,S1) and Ch1,2 (W1 / OAM1,S2). Wave W1 has orbital angular momentum OAM1.

[0042] Figure 5 shows a general example of two twisted electromagnetic waves W1, W2 generated by the same Tx of Figure 1, with orbital angular momentum OAM1 and OAM2, respectively, and with their wavefronts divided into the same sectors S1-Sp. The second wave W2 therefore associates the same number of channels of wave W1 with its OAM2, thus doubling the number of channels. The additional channels are denoted Ch2,1(W2 / OAM2,S1) and Ch2,2(W2 / OAM2,S2).

[0043] The Rx receiving device is placed at a certain distance from the Tx, a plurality of R1-Rm receiving antennas; discrimination means (20) operatively associated with the receiving antenna and adapted to carry out measurements of the amplitude and phase of the electromagnetic field corresponding to different receiving points (R), in order to obtain first data (DATA1) representative of the identity of the electromagnetic waves W1-Wk and to process said DATA1 into second data (DATA2) representative of the identity of sectors S1,...,Sp of each wavefront; Includes:

[0044] Finally, discrimination means (20) are configured to process the second DATA2 data to obtain third DATA3 data, which, if present, make it possible to distinguish between data transmission channels Chx,x in different S1-Sp sectors of various wavefronts.

[0045] FIG. 1 shows an example of a transmission device 2, in which T1-Tn antennas are arranged to define an (ideal) transmission surface T and a transmission direction D perpendicular to that surface. Such an ideal transmission surface is, for example, a transmission plane. Preferably, the antennas are arranged in a radial pattern around the D axis perpendicular to the transmission surface. Overall, the wavefront is omnidirectional and modulated sector-by-sector. If it is necessary to communicate with an Rx target that moves relative to the Tx, or in any case, moves towards a predetermined direction, receiver-directed or tracking modulation is used, while the carrier remains omnidirectional.

[0046] More generally, there are two cases. In the first case, the wave is omnidirectional, and therefore the D-axis is perpendicular to the propagation plane, and modulation of the omnidirectional carrier towards a given Rx receiver is performed using one part of the antenna. In the second case, the wave is not omnidirectional, but propagates from point A to point B. This also makes it possible to modulate different sectors independently, for example, for satellite transmission to different users. This communicates to Earth, but along different directions, using different modulations, always transmitting different channels in different directions. In this case, the D-axis coincides with the propagation axis.

[0047] In the example of Figure 1, the receive antennas R1-Rm are positioned to intersect the wavefront and define an (ideal) receive surface R perpendicular to the transmission direction D. This ideal receive surface is, for example, the receive plane.

[0048] In the following, alternative forms of embodiment of the present invention are described, in which elements that are the same as or similar to elements previously described are designated by the same reference numerals or by the same numbers increased by 100 or multiples thereof.

[0049] Figures 2-4 and 6-7 show an alternative form of implementation of a wireless communication system generally designated by reference numeral 101, which differs substantially from the device 1 described above in that the mutual arrangement of the transmit and receive antennas is different.

[0050] Specifically, the Tx102 transmission device has T1-Tn antennas arranged to define a transmission surface T and a transmission direction parallel to the surface, with, for example, a cylindrical or conical wavefront.

[0051] The Rx 103 receiving device has R1-Rm receiving antennas positioned to envelop the propagation wavefront transmitted by Tx.

[0052] For example, when the wavefront is cylindrical or conical about the D axis, the receive antennas R1-Rn are arranged in a radial pattern about the axis.

[0053] For example, the R1-Rm receive antennas can be arranged to define multiple receive surfaces concentric with the D axis.

[0054] For example, the discriminator 20 of the Rx103 device can be configured to perform an anamorphic transformation of the affine homology of a wavefront propagating with conical or cylindrical symmetry about the D axis.

[0055] The two devices 1 and 101 are capable of generating the same channel.

[0056] For completeness, Figure 7 shows a general example of two twisted electromagnetic waves W1, W2 generated by the same Tx of Figures 2, 3, and 4, with their respective orbital angular momenta OAM1 and OAM2; note that the wavefronts are divided into the same S1-Sp sectors. The second wave W2 therefore doubles the number of channels, associating the same number of channels of wave W1 with its OAM2. The additional channels are denoted Ch2,1(W2 / OAM2,S1) and Ch2,2(W2 / OAM2,S2).

[0057] Generally, in practice, multiple channels can be advantageously associated with each OAM wave by independently modulating non-overlapping sectors of the wavefront.

[0058] In other words, the modulation of the S1-Sp sectors of the wavefront of each OAM wave can be considered a substantial novelty, which identifies at least one of the data channels Chx,x that are transmitted simultaneously, in the same OAM mode, fixed or selective, either omnidirectionally or along one direction, at the same carrier frequency.

[0059] This represents an important differentiating factor compared to known art devices.

[0060] In the present invention, as a whole, each received torsional OAM electromagnetic wave corresponding to the entire receiving plane is associated with a data channel Chx,x, whose identification quantity is constituted by the orbital angular momentum OAM of the W1-Wk wave itself.

[0061] Therefore, in order to detect the identification quantity (i.e., OAM) of a given data channel Chx,x, it is necessary to know the exact rotation value of the wavefront phase of the received electromagnetic wave corresponding to the receiving surface R, and then perform a phase measurement of the electromagnetic field on the corresponding receiving surface R, corresponding to a selected wavefront sector.

[0062] In practice, by appropriate selection of some of the antennas comprising the Tx array, only one or more angular sectors of the selected OAM wave are modulated to communicate with the desired receiver Rx. Those used to communicate to the selected Rx receiving users transmit codes, symbols, or other types of signals modulated onto the OAM-bearing wave, while the remaining antennas can cause jamming or communicate with other Rx users, for example, by transmitting random signals or signals.

[0063] The OAM transmission of the present invention is referred to as "selective transmission" because it preferably uses electronic feedback (but does not exclude mechanical feedback) to appropriately activate one or more antennas transmitting the OAM, activating one or more T1-Tn antennas directed at one or more Rx receiving devices, to direct the desired transmission within a specific angular sector of an omnidirectional beam that identifies the direction of the receiving station (and thus other potential sources of jamming). This system also allows for flexible pointing and narrowing of each angular sector (or cone) of communication where the communication modulation is present. The remaining wavefronts are potential sources of jamming with appropriately chosen modulation.

[0064] General Definitions As is known from the literature, the OAM of an electromagnetic wave is a quantity that uniquely characterizes the azimuthal phase distribution of the wave front on a plane perpendicular to the propagation of the wave itself and around its own propagation axis D.

[0065] More precisely, the OAM associated with an electromagnetic wave is characterized by an integer quantity (a positive or negative integer) that represents the number of complete rotations (i.e., 360 degrees) made in the wavefront within a distance equal to the wavelength in either the left-handed or right-handed direction.

[0066] Electromagnetic waves with non-zero OAM have regions in the vicinity of the line aligned with the direction of propagation where the electromagnetic field, also known as an electromagnetic vortex, has near-zero intensity and amplitude. This phenomenon is due to the diffraction effect of long-distance transmission of electromagnetic waves.

[0067] Electromagnetic waves with integer values ​​of OAM have a characteristic intensity structure with axial symmetry in the form of concentric rings, characterized by different values ​​of the intensity of the electromagnetic field on a plane perpendicular to the propagation axis (technically, a "doughnut"), and a phase structure, formed by the phase of the wave front, characterized by a finite number of spirals wound along the propagation direction D, and in the far field, properties that are independent of the polarization state of the wave itself (technically, "fusilli"). In this case, we can say that the electromagnetic wave preferably has a well-defined spatial structure of phase and amplitude that is preserved during propagation in a homogeneous medium.

[0068] The present invention associates at least two independent data transmission channels with an electromagnetic wave having a specific carrier frequency and a specific OAM.

[0069] The definition of "data transmission channel" (or "data channel") is used herein to denote a signal that carries information, without any limitation as to, for example, the type of signal (audio, video, multimedia, digital data interchange, etc.) or the technological method used to generate and transmit it, including both analog and digital.

[0070] Multi-user omnidirectional distribution using OAM states preferably benefits from multiplexing data transmission channels after a topological transformation of the wavefront. The intersection of the measurement plane (or surface) with the D axis of propagation of the OAM wave is considered as a coordinate singularity, and the OAM wave is transformed to a symmetry axis coinciding with D for propagation perpendicular to it, according to the rules of geometric anamorphic transformation of affine homology. For example, a directional OAM beam characterized by a doughnut-shaped wavefront with a central vortex (characterized by always having zero magnetic field strength and being the center of symmetry for any integer value of OAM) reflects on the surface of a cone whose axis coincides with the propagation axis of the electromagnetic wave beam (D axis), and thus reflects omnidirectionally on a plane perpendicular to the D axis of propagation.

[0071] Given a single OAM mode, and the symmetry of the field intensity is known with respect to the D axis in a plane perpendicular to it, an anamorphic affine homology transformation transforms this figure into a wavefront with conical or preferably cylindrical symmetry, preserving the field intensity symmetry, and transforms the original "fusilli" spatial phase structure into a spiral centered at D, the pitch of which is determined by the phase shift imposed by the value of the OAM itself.

[0072] As indicated above, the present invention provides an apparatus and method for creating a wireless link that allows multiplexing of each individual OAM channel by dividing the wavefront of each OAM electromagnetic wave into different sectors that share the same carrier wave that is independently modulated in amplitude, frequency, polarization, or phase in each of these sectors.

[0073] In this way, the physical and structural properties of the original carrier wave are preserved during propagation, guaranteed by the well-known topological stability of OAM waves, and therefore, by dividing the wavefront into sectors, the data carrying capacity of each wave is increased and its stability is improved after propagation.

[0074] The definitions "carrier" or "carrier wave" are used herein to denote a general electromagnetic wave or electrical signal with known frequency, amplitude, polarization, and phase characteristics, which is typically modified by an information-containing modulating signal and then transmitted wirelessly or by other methods used by current technology, such as fiber, waveguide, or cable.

[0075] The definition of "sector" is used herein to denote a portion of the wavefront of an OAM electromagnetic wave that retains its structure during its propagation towards at least one receiving Rx user.

[0076] Example As already mentioned, in general, the present invention describes an apparatus 1 for creating a wireless link with waves propagating along a propagation axis D, and alternative configurations of such an apparatus, where, following an anamorphic transformation of affine homology, the wavefront of such an electromagnetic wave propagates with cylindrical or conical symmetry in a direction perpendicular to the axis itself. In each of the configurations, the wavefront of a sample electromagnetic wave W is split into multiple instances S1-Sp where the wavefront is independently modulated.

[0077] The device 1 comprises a number of transmission antennas T1, T2, ..., TN, which are capable of transmitting an electromagnetic wave W1 (characterized in an OAM mode by a precise integer value OAM1 = 11) and at least one other wave W2 (with a different value OAM2 = 12), in this case forming a pair of electromagnetic waves.

[0078] The OAM value of at least one wave will necessarily be different from 0, but it is not excluded that the antenna can also simultaneously generate a "standard" wave with OAM=0 that can be used, for example, as a jamming channel for other waves at the same frequency.

[0079] As already mentioned, the plurality of antennas T1, T2, ..., TN are preferably adapted to transmit a set of electromagnetic waves W1, W2, ..., Wk with different OAM values ​​and to independently modulate each of the OAM carriers with selected sectors S1, S2, ..., Sp of each wavefront.

[0080] The electromagnetic waves W1, W2, ..., Wk preferably have the same carrier frequency, in the range of 30 KHz to 300 GHz, and propagate uniformly such that the wavefront propagates along a direction perpendicular to a given axis having a direction D, or alternatively along the axis itself.

[0081] Preferably, the device 1 comprises a plurality of transmitting antennas T1, T2, ..., TN, which are arranged in a transmission plane T perpendicular to the direction D and are suitable for transmitting pairs of electromagnetic waves W1, W2 along propagation directions perpendicular to D.

[0082] Preferably, the transmission antennas T1, T2, . . . , TN are arranged corresponding to a set of transmission points t1, t2, .

[0083] Preferably, the transmitting antennas T1, T2, . . . , TN are positioned along at least one circumference or ellipse located on said transmitting surface T.

[0084] The transmitting antennas T1, T2, . . . , TN are preferably located in a transmission plane T and arranged on a single circumference or ellipse centered on an axis D.

[0085] However, some forms of implementation of the present invention (not shown) contemplate that the transmit antennas T1, T2, ..., TN are arranged on a circumference or ellipse with several concentric centers (or foci) on the same plane perpendicular to D, or on a plane parallel to the D axis, or share a single attachment point on the D axis and open in a radial pattern.

[0086] Preferably, the second driving means 10 may be electronic means operatively associated with the transmitting antennas T1, T2, . . . , TN for adjusting the transmission of the electromagnetic waves W1, W2.

[0087] The driving means 10 may include any type of analog or digital circuit, as appropriate.

[0088] The transmission of the electromagnetic waves W1, W2 can be performed in a known multiplexing manner: for example, the driving means 10 can drive the transmitting antennas T1, T2, ..., TN with corresponding transmission signals, each of which is characterized by a different phase.

[0089] In this way, an array of transmitting antennas T1, T2, ..., TN can easily generate electromagnetic waves W1, W2, ..., Wk that are superimposed on one another but are characterized by different orbital angular momenta.

[0090] Preferably, in the configuration shown in FIG. 1, the axes of the transmit antennas T1, T2, . . . , TN are oriented along the propagation direction D so as to converge at the midpoint between the transmission plane T and the reception plane R.

[0091] Alternatively, in the configurations of Figures 2, 3 and 4 obtained by anamorphic transformation of affine homology, the axes of the transmitting antennas T1, T2, ..., TN are oriented so as to converge at the midpoint of the common coupling point between the transmitting plane T and the receiving surface R concentric with it, in a direction perpendicular to the propagation direction D.

[0092] In some forms of embodiment of the present invention, the transmission antennas T1, T2, ..., TN may consist of very simple structures, such as Yagi-Uda antennas, parabolic bodies of revolution, holes in metal protectors, or "backfire antennas," thereby reducing the cost of building the transmission system of the device 1,101.

[0093] Preferably, the transmitting antennas T1, T2, ..., TN can be fabricated using dielectric, hybrid optical, metamaterial, and / or plasmonic materials to further improve their directivity.

[0094] Preferably, the driving means 10 are capable of associating at least one transmission channel Chx,x with an electromagnetic wave W1 superimposed on waves W2, . . . , Wk.

[0095] To this end, encoding means, including known means, may be operatively associated with or integrated into the driving means 10 for transmitting data along the Chx,x transmission channel.

[0096] Preferably, the modulation means 11 independently modulates the wavefronts of the wavefront sectors (S1, S2, ..., Sp) using respective carrier waves of electromagnetic waves with OAM ≠ 0 (i.e. both 0 > and 0 < are possible).

[0097] Preferably, means (not shown) for adjusting the polarization state of the electromagnetic waves W1-Wk are operatively associated with or integrated into the modulation means 11.

[0098] In this way, the data transmission channel can be doubled using the degrees of freedom provided by the polarization.

[0099] Preferably, the transmission antennas T1, T2, ..., TN transmit a plurality of electromagnetic waves W1-Wk, each of which can be associated with at least one different transmission channel Chx,x for each sector S1-Sp of the wavefront.

[0100] The receiving device 3, 103 generally includes a number of receiving antennas R1, R2, ..., RM capable of simultaneously receiving a set of these electromagnetic waves W1, W2, ..., Wk superimposed on one another.

[0101] A set of electromagnetic waves W1, W2, ..., Wk is preferably each used to carry a certain distance of k*P different signals of the data channel (where k is the number of waves and P is the number of sectors of each wavefront), and carrier waves P1, P2, ..., Pk are each associated with that set.

[0102] The electromagnetic waves W1, W2, ..., Wk are each characterized by a different orbital angular momentum (e.g., first and second orbital angular momentum m1, m2, ..., mk), where m1, m2, ..., mk are different integers (positive or negative integers). In some cases, one of the electromagnetic waves W1, W2, ..., Wk may have zero orbital angular momentum (in which case the electromagnetic wave is not a torsion wave but can still be used, for example, for jamming modulation).

[0103] Each carrier P1, P2, ..., Pk of each electromagnetic wave W1, W2, ..., Wk can be separately and independently modulated in different sectors S1, S2, ..., Sp to increase the capacity of each wave by at least p times compared to a channel utilizing the entire wave field. Each of the Sj sectors (l ≤ j ≤ p) can advantageously be used as an independent data channel to distribute information along a given direction towards different users.

[0104] As shown schematically in Figure 1, on its path to the receiving antennas R1, R2, ..., RM, the wavefront of each of the electromagnetic waves W1, W2, ..., Wk rotates around a propagation axis D on the entire plane perpendicular to this propagation direction. Thus, the electric field of each of the electromagnetic waves follows a set of spiral trajectories in space extending along the propagation direction D (spiral axis).

[0105] As mentioned above, each angular momentum represents the number of complete rotations made by the wavefront of an electromagnetic wave, per wavelength, while the direction of rotation of each wavefront of an electromagnetic wave is represented by the magnitude and sign of its orbital angular momentum.

[0106] The receiving antennas R1, R2, . . . , RM are arranged on a receiving surface R, which in FIG. 1 identifies a plane intersecting the propagation direction D of the electromagnetic waves, and are positioned at a distance Z relative to the source T of the electromagnetic waves themselves.

[0107] Preferably, the receiving antennas R1, R2, ..., RM are arranged corresponding to a plurality of points r1, r2, ..., rM belonging to the receiving plane R, which are suitably positioned to use, at least in pairs, each of the observation sectors Sr1, Sr2, ..., Srp corresponding to the wavefront sectors S1, S2, ..., Sp constituting the electromagnetic waves W1, W2, ..., Wk.

[0108] Preferably, the receiving antennas R1, R2, . . . , RM are positioned along at least one circumference or closed curve located at R and centered on the propagation direction D of the electromagnetic waves W1, W2, .

[0109] The receiving antennas R1, R2, . . . , RM are preferably arranged on one or more circles or closed curves on the receiving surface R.

[0110] The number of receive antennas M can vary as needed.

[0111] The number p of sectors of each of the electromagnetic waves W1, W2, . . . , Wk can advantageously vary depending on the respective radiation wave.

[0112] Preferably, M is an even number equal to or greater than 2.

[0113] The receiving surface R is preferably arranged substantially perpendicular to the propagation direction D of the electromagnetic waves W1, W2, . . . , Wk.

[0114] The receiving device Rx3, 103 includes discrimination means 20 (eg, electronic means) operatively associated with the receiving antennas R1, R2, . . . , RM.

[0115] The determining means 20 may include any type of analog or digital circuitry, as appropriate.

[0116] The discrimination means 20 are suitable for carrying out measurements of the amplitude and phase of the electromagnetic field on the receiving surface R corresponding to the observation sectors Sr1, Sr2, . . . , Srp in order to obtain the first DATA1 data.

[0117] The discrimination means 20 is also suitable for processing the DATA1 data obtained from the above-mentioned amplitude and phase measurements of the electromagnetic field ER, separating the OAM channels associated with the waves W1, W2, ..., Wk, and deriving DATA2 data for subdividing and identifying each OAM carrier in each of the sectors Sr1, Sr2, ..., Srp.

[0118] The discrimination means 20 can also further process the DATA2 data thus obtained, in order to obtain third DATA3 data by decoding each general channel Chx,x obtained by multiplexing the OAM data channels in the corresponding sector Sj of the general OAM electromagnetic wave Wq (l≦q≦k) using analog or digital techniques, for example so that the final output signal from the Rx receiving device of the apparatus 1,101 includes one and only one of the data channels.

[0119] Preferably, the discrimination means 20 receives from each of the receiving antennas R1, R2, . . . , RM a received signal detected at one of the observation points r1, r2, .

[0120] By processing the DATA1 measurement data, which indicates the amplitude of the resulting electromagnetic field ER on the receiving plane R, it is therefore possible to recognize a function representing the amplitude distribution of the electromagnetic field on the receiving plane R, and thus also to obtain DATA2 data, which indicates the difference in angular momentum of the electromagnetic waves W1, W2, ..., Wk and their separation on reception.

[0121] As explained above, the discrimination means 20 is capable of obtaining DATA2 data that indicates the differences between various OAM waves.

[0122] Preferably, as described above, multiple channels can be associated with each OAM wave by independently modulating non-overlapping sectors of the wavefront.

[0123] In the receiving device Rx3, 103, the acquisition of the data transmitted over the data channel C can advantageously be carried out by suitable decoding means (not shown) of a known type operatively associated with or even integrated into the discrimination means 20.

[0124] Preferably, the receiving antennas R1, R2, . . . , RM are capable of receiving a plurality of electromagnetic waves W1, W2, W3, W4 (FIG. 1) of wavefront sectors, considered for example as S1, S2.

[0125] Preferably, the receiving antennas R1, R2, . . . , RM are movable over the receiving surface R as required.

[0126] Thus, the positions of the observation points r1, r2, . . . , rM on the receiving surface R can be varied as needed to optimize the reception of the superimposed electromagnetic waves W1, W2, .

[0127] Preferably, the observation points r1, r2, . . . , rM are located near the maximum point of the absolute value of the electromagnetic field ER.

[0128] The receiving antennas R1, R2, ..., RM may consist of dipoles, parabolic bodies or other known types of structures. Metamaterials and / or plasmonic materials can be advantageously used for their realization.

[0129] The number N of receive antennas can vary as needed, but preferably N is an even number greater than or equal to 2.

[0130] In general, the use of a remote wireless link made in accordance with the present invention can perform the following steps:

[0131] activating a section of the transmitting antenna to transmit an analog or digital communications channel in a well-established direction obtained by appropriate analog or digital modulation;

[0132] activating that section of the transmitting antenna so as to illuminate only the receiving station, and preferably transmitting jamming modulation in the remaining directions.

[0133] Directing the transmission in an active feedback manner to optimize the transmission of information to the recipient.

[0134] receiving at least one electromagnetic wave W1 with orbital angular momentum OAM=11 in a direction perpendicular to the propagation direction D, or alternatively in accordance with an anamorphic transformation of the affine homology of the wavefront, the receiving surface R being positioned at a constant distance relative to a source T of at least one of the electromagnetic waves W1, W2, ..., Wk;

[0135] A step of performing measurements of the amplitude and phase of the electromagnetic field to obtain first DATA1 data indicating the amplitude and phase distribution of the electromagnetic field ER resulting from the superposition of the electromagnetic waves W1, W2, ..., Wk corresponding to the observation points r1, r2, ..., rM.

[0136] A step of processing the first DATA1 data to obtain second DATA2 data that allows separating the electromagnetic waves W1, W2, ..., Wk into respective carrier signals of the selected wavefront sector S.

[0137] Preferably, it is also possible to process the second DATA2 data to obtain third DATA3 data, which, if present, makes it possible to distinguish between data transmission channels multiplexed in the various sectors S.

[0138] Preferably, the method according to the invention also comprises - identifying, on a receiving surface R, the maxima and minima of the electromagnetic field ER resulting from the superposition of the electromagnetic waves W1, W2, ..., Wk; identifying observation points r1, r2, ..., rM based on the number and locations of said minima in the wavefront sector S; aggregating channels in each wavefront sector to increase the data transfer capacity of a single OAM wave; associating one or more different users with each of the wavefront sectors S for transmission of single or broadcast data; Includes:

[0139] In practice, it has been confirmed that the device and method according to the invention make it possible to overcome the drawbacks described in the known art and achieve the set goals by associating multiple channels and multiple users with the same single OAM value.

[0140] The apparatus and method according to the present invention provides simple amplitude and phase measurements of the electromagnetic field to detect this distinguishing feature in a selected sector of the wavefront.

[0141] Thus, the apparatus and methods according to the present invention are relatively simple and inexpensive to implement in practice compared to communication systems and methods of known art.

[0142] The apparatus and method according to the present invention involves the use of antennas for receiving / transmitting with fairly simple geometries and which are easy to use in practice.

[0143] General interpretation of terms For the purposes of the present invention, the term "comprehending" and its derivatives as used herein are to be understood as open-ended terms, which specify the presence of stated features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other, unstated features, elements, components, groups, integers, and / or steps. The above open-ended terms also apply to terms with similar meanings such as "including," "having," and their derivatives. Furthermore, terms such as "part," "section," "portion," "member," or "element," when used in the singular, can have two meanings: a single part or multiple parts. As used herein to describe the above operating configuration(s), the following directional terms, such as "forward," "backward," "above," "down," "vertical," "horizontal," "below," and "transverse," and any other similar directional terms, refer to the operating configuration described in the operating position. Finally, as used herein, terms of degree, such as "substantially," "about," and "approximately," refer to a reasonable amount of deviation from the modified term so as not to significantly change the end result.

[0144] While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this description that various modifications and variations can be made without departing from the scope of the present invention as defined in the appended claims. For example, the size, shape, position, or orientation of various components can be modified as necessary and / or desired. The components shown may be directly connected to one another or in contact with one another, with intermediate structures disposed between the components. The function of one element may be performed by two elements, and vice versa. The structure and function of one implementation may be adopted in another implementation. At the same time, not all advantages need be present in a particular implementation. Furthermore, any features that are original compared to known technology, alone or in combination with other features, should be considered a separate description of the applicant's additional invention, including the structural and / or functional concepts incorporated by those features. Therefore, the foregoing description of embodiments according to the present invention is provided for illustrative purposes only, and not for the purpose of limiting the present invention as defined by the appended claims and their equivalents.

Claims

1. A set of communication channels comprising a plurality of first channels (Ch11, Ch12) at the same carrier frequency, said set comprising at least one first carrier electromagnetic wave (W1) carrying orbital angular momentum (OAM), i.e., the phase is twisted around a predetermined twist axis (D), the wavefronts of said wave being divided into mutually different spaces to form propagation sectors (S1...Sp), each of said first channels comprising: the orbital angular momentum (OAM1) of the first wave (W1); one of said sectors (S1...Sp) of said first wave (W1), said wave being modulated differently from the other sectors; A set of communication channels characterized by

2. 2. A set according to claim 1, characterized by the fact that said sectors (S1...Sp) are placed next to each other in the circumferential direction around said torsion axis (D).

3. The set includes at least one second carrier electromagnetic wave (W1) carrying orbital angular momentum (OAM), i.e., phase twisted around a predetermined torsion axis (D) at the same frequency as the first wave, the first and second waves being characterized by different orbital angular momentum (OAM1, OAM2), and the set of channels includes a plurality of second channels (Ch21, Ch22), each of which: the orbital angular momentum of the second wave (OAM2); a propagation sector (S1...Sp) among a plurality of propagation sectors in which the wavefront of said second wave is subdivided, said second wave being modulated in said sector in a different way than in the other sectors; 3. The set according to claim 1 or 2, characterized by the fact that

4. 4. The set according to claim 3, characterized by the fact that the two waves have a common transmission source.

5. 5. The set according to claim 4, characterized by the fact that the two waves have the same twist axis (D) and their propagation sectors coincide.

6. A set according to any of the preceding claims, characterized by the fact that at least one of the channels is defined by a modulation of at least one communication signal, while at least one of the other channels is defined by a jamming modulation.

7. A set according to any of the preceding claims, characterized by the fact that the channels are omnidirectional.

8. A multi-channel communication device comprising at least one wireless transmission device (2, 102) (hereinafter, simply referred to as Tx) and at least one wireless reception device (3, 103) (hereinafter, simply referred to as Rx), The Tx transmission device (2, 102) a plurality of transmit antennas (T1-Tn); a plurality of modulation sections (S1-Sp) each defined by a group of said antennas operatively associated with one another; - driving means (10) configured to drive said T1-Tn antennas to generate at least one carrier electromagnetic wave (W1), the phase of which is twisted about a predetermined twist axis (D) and is characterized by an orbital angular momentum (OAM1) and a carrier frequency; - modulation means (11) operatively associated with said sections (S1-Sp) adapted to modulate corresponding sectors of the wavefront of said electromagnetic wave (W1) with orbital angular momentum (OAM), the modulations of said sectors being independent of each other and defining respective channels (Ch11, Ch12, Ch21, Ch22) at the same carrier frequency; 1. A multi-channel communication device, characterized by the fact that it comprises:

9. The at least one Rx receiving device (3, 103) is installed at a certain distance from the Tx transmitting device; a number of receive antennas (R1-Rm); discrimination means (20) operatively associated with said receiving antenna and adapted to perform measurements at different receiving points (R) in order to obtain first data (DATA1) representative of the discrimination of said electromagnetic waves (W1) and to process said DATA1 into second data (DATA2) representative of the discrimination of said sectors (S1-Sp) of said respective wavefronts; 9. The device according to claim 8, characterized by the fact that it comprises:

10. 10. Device according to claim 9, characterized by the fact that said discrimination means (20) are arranged to perform at least a phase measurement, preferably an amplitude and phase measurement.

11. 11. The device according to claim 9 or 10, wherein the discrimination means (20) are configured to process the second DATA2 data in order to obtain third DATA3 data, characterized by the fact that, in the presence of a modulation of the data signal, different sectors (S1-Sp) of the various wavefronts corresponding to an equal number of data transmission channels (Chx, x) are distinguishable.

12. 12. The apparatus according to any one of claims 9 to 11, characterized by the fact that the Tx transmission device (2, 102) is configured to generate the plurality of carrier electromagnetic waves (W1-Wk) characterized by different orbital angular momenta (OAM1, OAM2) whose phases are twisted around a predetermined twist axis (D), and the discrimination means (20) is configured to distinguish each of the electromagnetic waves (W1-Wk) compared to other electromagnetic waves (e.g., the discrimination means (20) performs phase measurements to detect the OAM of each wave).

13. Apparatus according to any one of claims 9 to 12, wherein said receiving antennas (R1-Rm) are movable between a number of different observation points.

14. 14. Device according to claim 13, characterized by the fact that the observation points are maxima and minima of the electromagnetic field ER resulting from the superposition of the electromagnetic waves (W1, Wk) on a receiving surface (R).

15. said Tx transmission device (2, 102) comprises a plurality of transmission antennas (T1-Tn) arranged in one of the following ways: A) the transmitting antennas (T1-Tn) are arranged to define a transmission surface (T) and a predetermined torsion axis (D) of the wave; said Rx receiving device (2, 102) comprises a number of receiving antennas (R1-Rn) arranged in one of the following ways: B) the receiving antennas (R1-Rm) are arranged to define a receiving surface (R) that intersects the torsion axis (D); C) the receiving antennas (R1-Rm) are arranged in a radial pattern around a predetermined axis (D); Device according to any of claims 8 to 14, characterized by the fact that

16. Device according to any of claims 8 to 15, characterized by the fact that said driving means (10) modulate at least one of the following: phase, amplitude, polarization, frequency, path diversity and other methods known in the art.

17. 17. Device according to claim 16, characterized by the fact that said modulation means (11) modulate at least one of the following: phase, amplitude, polarization, frequency, path diversity and other methods known in the art.

18. Device according to any of claims 8 to 17, characterized by the fact that said device comprises directional feedback means adapted to direct the mutual position of said transmission direction (D) and reception direction.

19. Device according to any of claims 8 to 18, characterized by the fact that said modulation means (11) comprise means for adjusting the polarization state of said electromagnetic waves (W1-Wk).

20. A multi-channel communication procedure, comprising: - generating at least one carrier electromagnetic wave (W1) carrying orbital angular momentum (OAM), i.e., whose phase is twisted around a predetermined twist axis (D) and characterized by the orbital angular momentum (OAM1) and the carrier frequency; - dividing the wavefront into independently modulated sectors (S1-Sp), each of which is considered a transmission channel (Chx, x) at said carrier frequency; receiving said wavefront and determining said channel; Multi-channel communication procedures, including:

21. 21. A procedure according to claim 20, characterized by the fact that said waves are transmitted by a plurality of spaced points (T1-Tn) defining said sectors (S1-Sp) and said determining comprises making at least one measurement at a plurality of spaced reception points (R1-Rm).

22. - generating a number of carrier electromagnetic waves (W1...Wk) whose phase is twisted around a predetermined twist axis (D) and with the same frequency and different orbital angular momentum (OAM1, OAM2), each wave being divided into wavefront sectors (S1-Sp) modulated independently of each other, each wave being considered as a transmission channel at the same frequency (Chx, x); receiving said wavefront and determining said channel; 22. The procedure of claim 20 or 21, comprising:

23. 23. A procedure according to any of claims 20 to 22, characterized by the fact that said sectors are modulated with at least one of the following: phase, amplitude, polarization, frequency, path diversity and other methods known in the art.

24. A procedure according to any of claims 20 to 23, characterized by the fact that on at least one of said channels (Chx, x) a modulation of at least one communication signal is transmitted and, at the same time, on the other of at least one of said channels a jamming modulation is transmitted.

25. Procedure according to any of claims 20 to 24, characterized by the fact that the transmission is directed by directional feedback means.

26. The method is characterized by receiving the electromagnetic waves (W1, Wk) at a receiving surface (R) at a plurality of observation points defined as follows: - identifying, on said receiving surface (R), the maximum and minimum points of the electromagnetic field ER resulting from the superposition of said electromagnetic waves (W1-Wk); - identifying the observation points (r1, rM) based on the number and location of the minima in the wave-field sector (S1-Sp), said procedure comprising moving a number of receive antennas (R1-Rm) between the observation points; The method according to any one of claims 20 to 25,

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