Radio wave hologram communication device and radio wave hologram communication method

Abstract

To provide a radio wave hologram communication device and a radio wave hologram communication method that allow a plurality of base stations and a plurality of terminals to perform stable radio communication by synchronizing a large number of base stations and appropriately controlling phases and timings.SOLUTION: A radio wave hologram communication device includes: an inter-base station synchronization unit that synchronizes phases of carrier waves transmitted from a plurality of base stations; an inter-base-station-and-terminal synchronization unit that synchronizes the base stations and a terminal; a measurement unit that measures the reception time, amplitude, and phase of a reference wave transmitted from the terminal and received by the plurality of base stations; a time adjustment unit that gives a specific time delay to information on the reception time, amplitude, and phase measured by the measurement unit; a waveform conversion unit that converts an output waveform to a specific waveform based on an output waveform from the time adjustment unit; and a transmitting unit that transmits a signal according to the output waveform from the waveform conversion unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a radio wave hologram communication device and a radio wave hologram communication method for a plurality of base stations and a plurality of terminals. [Background technology]

[0002] The service area of ​​mobile communications such as mobile phones is an area where a wireless channel can be set up to connect a base station and a terminal. Until now, the design of a surface service area has been based on minimizing areas where radio waves cannot reach, and on minimizing the effects of interference caused by radio waves from multiple base stations. This makes it possible for terminals (also called User Equipment, or UE) to communicate via a wireless channel with a base station (Non-Patent Documents 1 and 2). In first- and second-generation mobile communication systems, multiple carrier frequencies are used, and therefore service areas are designed taking into consideration the repetition of carrier frequencies (Non-Patent Documents 1 and 2).

[0003] Because the third-generation mobile communication system has fewer carrier frequencies than the first- and second-generation mobile communication systems, it uses technology to reduce interference from adjacent service areas.Furthermore, the fourth-generation mobile communication system uses orthogonal frequency division multiple access (OFDMA), which allows adjacent service areas to use the same carrier frequency.

[0004] Although mobile communications service area design has thus incorporated numerous technological innovations, it does not deviate significantly from the original design guidelines, which were to minimize areas where radio waves cannot reach and to minimize the effects of interference caused by radio waves from multiple base stations. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] "Automobile Telephones," edited by the Institute of Electronics, Information and Communication Engineers, 1985. [Non-patent document 2] Yoshihisa Okumura and Masaaki Shinji, editors, "Fundamentals of Mobile Communications," edited by the Institute of Electronics, Information and Communication Engineers, 1986 Summary of the Invention [Problem to be solved by the invention]

[0006] In wireless communications, one possible way to improve communication speeds is to increase the carrier frequency, which allows for a wider bandwidth. Generally, increasing the carrier frequency makes long-distance propagation difficult due to absorption and scattering by water vapor, rain, and snow. Furthermore, as wavelengths become shorter, it becomes more difficult for radio waves to bend around and reach the backsides of various structures in our everyday lives, limiting the reach of radio waves in many places. As a result, it becomes unavoidable to install additional antennas in various locations to eliminate so-called dead zones.

[0007] In this environment, negative aspects such as rising costs and system complexity become apparent. The use of multiple antennas becomes inevitable, and the adverse effects of unintended interference become a major problem. In response to demands for improved communication speeds, methods using multiple antennas, such as Massive MIMO (Multiple-Input Multiple-Output), have been put into practical use. However, these methods require the antennas to be aligned in a relatively narrow spatial area, and beamforming is performed, using the multiple Massive MIMO antennas as if they were a single highly directional antenna.

[0008] In conventional mobile communications, the ideal is to configure the coverage areas (cells) of multiple base stations so that they do not overlap and are packed as closely as possible with hexagonal cells. At cell boundaries, communication is easily hindered by interference from adjacent base stations. Furthermore, if there are blank areas where no radio waves from any base station can reach a certain area, or if they can reach a certain area but the electric field is weak, convenience is significantly reduced. Therefore, when designing a service area, it is necessary to appropriately design cell boundaries. However, it is essentially impossible to suddenly attenuate radio wave strength as soon as it crosses a certain boundary.

[0009] In conventional mobile communications, base stations are spaced far apart, resulting in a small angle, close to horizontal, from the terminal's perspective. The propagation space between these base stations is filled with natural and man-made structures, resulting in multipath interference due to diffraction. However, as carrier frequencies become higher in the future, more base stations will be required, shortening the distance between base stations and increasing the upward angle at which terminals view them. It will also become possible to transmit radio waves from the sky using drones and balloons. These changes in the radio equipment environment will make it easier to receive direct waves, but there are concerns that the ability to receive radio waves from multiple base stations will increase unintended interference.

[0010] The following disclosure has been devised in light of the current situation, and aims to provide a radio wave hologram communication device and radio wave hologram communication method that enable stable wireless communication between multiple base stations and multiple terminals by synchronizing multiple base stations and appropriately controlling the phase and timing.

[0011] Rather than the conventional approach of eliminating interference, this concept involves intentionally creating interference at the terminal location to create a high electric field strength, and instead actively utilizing interference to control the spatial distribution of the electric field within the communication area. [Means for solving the problem]

[0012] One aspect of the present disclosure is a radio wave hologram communication device comprising: an inter-base station synchronization unit (inter-base station synchronization unit 110) that synchronizes the phases of carrier waves transmitted from multiple base stations (base stations 100); a base station-terminal synchronization unit (base station-terminal synchronization unit 120) that synchronizes the base stations with terminals; a measurement unit (measurement unit 130) that measures the reception time, amplitude, and phase at which the multiple base stations receive a reference wave transmitted from the terminal; a time adjustment unit (time adjustment unit 150) that imparts a specific time delay to the information on the reception time, amplitude, and phase measured by the measurement unit; a waveform conversion unit (waveform conversion unit 160) that converts the output waveform from the time adjustment unit into a specific waveform based on the output waveform; and a transmission unit (transmission unit 170) that transmits a signal according to the output waveform from the waveform conversion unit.

[0013] In this type of radio wave hologram communication device, the base station inter-synchronization unit synchronizes the phases of the carrier waves of multiple base stations, and the base station inter-terminal synchronization unit synchronizes the base stations and terminals. This mutual synchronization allows the entire communication system, including the terminals, to operate coherently with aligned phases and timing.

[0014] The terminal then transmits a reference wave, which is received by multiple base stations, and the measurement unit measures the time, amplitude, and phase of the received signal. Measuring the time makes it possible to correct not only the geometric distance but also the electrical distance, taking into account the electromagnetic influence of the medium along the way. The amplitude and phase are information about the signal itself, but when signals from multiple terminals overlap to form a hologram, it also contains information about the terminal's location, which has the effect of making it possible to measure location information as well.

[0015] Next, the information recording unit stores information on the reception time, amplitude, and phase, which is equivalent to stopping information flying away at the speed of light, and has the effect of enabling subsequent signal processing.

[0016] Next, the time adjustment unit applies a desired time delay to the recorded information, thereby correcting the adverse effects of loss of coherence due to differences in distance or the state of the propagation medium when radio waves are sent back from the base station to the terminal.

[0017] The waveform converter has the function of converting the output waveform of the time adjuster into a desired waveform, and also functions as a switch that connects specific terminals by holographic interference.

[0018] The transmitter transmits radio waves from the base station to the terminal, enabling two-way communication. Radio waves transmitted from multiple base stations with appropriate phase and timing propagate through the medium until the phase and timing match exactly at the location of the terminal, resulting in high electric field strength. This allows the radio wave hologram communication device to control the electric field strength distribution to the desired distribution in three-dimensional space.

[0019] In one aspect of the present disclosure, the waveform conversion unit may convert the reference wave transmitted from a first terminal into a first inverted waveform inverted over a time range until the arrival of the reference wave is completed at the base station from which the first terminal is furthest among the plurality of base stations that receive the reference wave, and the transmission unit may perform parallel redundant communication via multiple routes between the first terminal and the plurality of base stations.

[0020] Such a radio wave hologram communication device emits a reference wave from a terminal, and at multiple base stations, the waveform of the received reference wave is recorded within the time range until the arrival of the radio wave from the farthest terminal is completed, and the order of the time (sampling clock) of the recorded waveform is reversed.

[0021] If the distance is short, the radio waves arrive early, and if the distance is far, they arrive late. To eliminate this time difference and align the phase, the waveform that arrived late is sent back early, and the waveform that arrived early is sent back late, so that the radio waves overlap at the same timing and phase at the original terminal location.

[0022] Furthermore, even if there is a time delay due to factors other than the geometrically shortest distance along the propagation path of radio waves, such as differences in dielectric constant, diffraction, or reflection, the time change of such effects is sufficiently slow compared to the propagation speed of the radio waves, and the time development of the radio waves on their outbound and inbound paths is symmetrical. Therefore, such adverse effects can be canceled out by using a time-reversed inverse waveform.

[0023] Furthermore, because there are many parallel paths created by the hologram, redundancy is provided, so even if there is a problem with one path, another path can compensate. These effects allow signals from nearby base stations to arrive sequentially, eliminating transient states at the rise of the waveform and enabling stable, high-speed communication.

[0024] At the location of a specific terminal of interest, the electric field strength increases due to the superposition, while at locations other than the terminal of interest, the phase changes randomly and the electric field strength decreases due to averaging caused by the superposition, which has the effect of making the system resistant to interference and improving privacy at the physical layer.

[0025] In one aspect of the present disclosure, the waveform conversion unit may convert the first inverse waveform to the second inverse waveform by inverting the waveform time over a time range until the arrival of the reference wave is completed at the base station where the second terminal is the farthest among the plurality of base stations that receive the reference wave transmitted from the second terminal, and by associating the first inverse waveform with the second inverse waveform, when transmitting a signal from the first terminal to the second terminal.

[0026] This type of radio wave hologram communication device performs the same operation at the second terminal as at the first terminal. This allows the inverse waveforms of both the first and second terminals to be determined. When communicating between the first and second terminals, when a waveform (or equivalently, an inverse waveform) is received from the first terminal, it is simply converted into a waveform (or equivalently, an inverse waveform) when a reference wave is received from the second terminal. This is because when an inverse waveform is transmitted from the second terminal, constructive interference (constructive interference) naturally occurs at the location of the second terminal.

[0027] Although the terminal here is referred to as a second terminal, the number of second terminals is not limited to one, and since linear addition is possible, even if there are multiple second terminals, it is possible to simultaneously distribute radio waves to multiple second terminals by transmitting a waveform in which the inverse waveforms of each terminal are superimposed.In other words, the radio wave hologram communication device is a switch that switches between terminals, and also functions as a distributor that can simultaneously distribute to multiple terminals.

[0028] In one aspect of the present disclosure, the time adjustment unit may utilize the arrival time difference due to different distances between the multiple base stations and a specific terminal, and adjust the transmission timing of signals from the multiple base stations so that the signals overlap with a time delay at the position of the specific terminal, forming a convolutionally coded signal.

[0029] This type of radio wave holographic communication device achieves the time shift required for convolutional coding by utilizing the difference in arrival time due to the different distances between multiple base stations and a specific terminal. Convolutional coding adds redundancy by overlapping current and past signals using the same signal sequence, but with a slight time shift. Modulated radio waves containing information overlap at the location of the specific target terminal, completing the convolutional coding. If the radio wave emission timing from the base station is appropriately adjusted, sequential convolutional coding is achieved the moment it arrives at the specific terminal. Convolutional coding cannot be performed at other terminal locations because the phase does not match. This has the effect of enabling high-speed error correction coding and encryption at the physical layer.

[0030] In one aspect of the present disclosure, the time adjustment unit may adjust a time delay required for trellis coding modulation in which redundant bits generated by convolutional coding are assigned to multiple modulation values.

[0031] This type of radio wave holographic communication device realizes convolutional coding using trellis-coded modulation by taking advantage of the difference in arrival times caused by the different distances between multiple base stations and a specific terminal. Trellis-coded modulation allocates redundant bits generated by convolutional coding to the multilevel modulation. This makes it possible to convert between Hamming distance and Euclidean distance in multilevel modulation in real time, which has the effect of improving bit error rate and coding efficiency.

[0032] In one aspect of the present disclosure, when the amount of uplink data transmitted from the terminal to the base station is small and the base station transmits the same data to multiple terminals, the time adjustment unit may lengthen the time period of the signal so that the difference in arrival time due to differences in distance from the base station to the terminal is sufficiently small compared to the time change of the signal.

[0033] This type of radio wave holographic communication device can function without time reversal when the amount of upstream data sent from the terminal to the base station is small and the base station is broadcasting the same data to multiple terminals.By lengthening the time period of the signal so that the difference in arrival time due to differences in distance from the base station to the terminal is sufficiently small compared to the time change of the signal, it is possible to send information to many more terminals simultaneously while maintaining control over the spatial distribution of the electric field.

[0034] In one aspect of the present disclosure, the transmitter may transmit a signal in which at least one of a carrier frequency and a subcarrier frequency is multiplexed.

[0035] Such a radio wave hologram communication device has the effect of enabling communication with a larger number of terminals and large-capacity communication by multiplexing using carriers and subcarriers with different frequencies.

[0036] In one aspect of the present disclosure, the transmitter may transmit a signal multiplexed using two orthogonal linearly polarized waves. Such a radio wave holographic communication device takes advantage of the fact that orthogonal linearly polarized waves do not interfere with each other, and has the effect of enabling an increase in communication channel capacity and an improvement in the S / N ratio and S / C ratio.

[0037] In one aspect of the present disclosure, the transmitter may transmit a signal multiplexed by left- and right-handed rotating circular polarization.

[0038] Such a radio wave hologram communication device takes advantage of the fact that circularly polarized waves with different rotation directions on the left and right do not interfere with each other, thereby enabling an increase in communication channel capacity and an improvement in the S / N ratio and S / C ratio. [Brief explanation of the drawings]

[0039] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a base station. [Figure 2] FIG. 2 is a diagram illustrating an example of a connection configuration between a base station and a terminal. [Figure 3]FIG. 3 is a diagram illustrating an example of the relationship between a base station and a terminal in time reversal holography. [Figure 4] FIG. 4 is a diagram illustrating the function of the waveform converter in time reversal holography. [Figure 5] FIG. 5 is a diagram illustrating the time transition of time reversal holography. [Figure 6] FIG. 6 is a diagram showing an example of the circuit configuration of a time adjustment unit of time reversal holography. [Figure 7] FIG. 7 is a diagram showing an input image of terminal position distribution for the numerical simulation. [Figure 8] FIG. 8 is a diagram showing the distribution of holograms in a plane on which the base station is located to obtain the distribution of FIG. [Figure 9] FIG. 9 is a diagram showing the distribution of electric field strength reproduced on a plane where a terminal is located due to interference when radio waves controlled according to a hologram are emitted from a base station. [Figure 10] FIG. 10 shows the time transition over 10 periods of the distribution of the electric field strength reproduced on a plane where a terminal is located when radio waves are simultaneously emitted from base stations. [Figure 11] FIG. 11 is a diagram showing the time evolution of the PSNR of the distribution of the electric field strength reproduced on a plane where a terminal is located. [Figure 12] FIG. 12 is a diagram showing the time evolution of the SNR of the distribution of the electric field strength reproduced on a plane where the terminal is located. [Figure 13] FIG. 13 is a diagram showing the change in the reconstructed image when the wavelength is shifted by ±10% from the center wavelength. [Figure 14] FIG. 14 is a diagram showing a comparison with the distribution of electric field strength reproduced on a plane where a terminal is located when the number of base stations is reduced to one-fourth. [Figure 15] FIG. 15 is a diagram illustrating convolutional coding using a time delay from an equidistant region. [Figure 16] FIG. 16 is a diagram showing trellis coded modulation using time delays from equidistant regions. [Figure 17]FIG. 17 is a diagram illustrating an example of the hardware configuration of base station 100 and terminal 200. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0040] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0041] (1) Base station configuration Fig. 1 shows an example of the functional block configuration of base station 100. As shown in Fig. 1, base station 100 includes an inter-base station synchronization unit 110, a base station-terminal synchronization unit 120, a measurement unit 130, an information recording unit 140, a time adjustment unit 150, a waveform conversion unit 160, and a transmission unit 170.

[0042] The inter-base station synchronization unit 110 synchronizes the phases of carrier waves transmitted from multiple base stations. Specifically, the inter-base station synchronization unit 110 has a function of synchronizing the phases of carrier waves among multiple base stations. For example, a high-speed, low-jitter master clock may be distributed via optical fiber, and each base station may synchronize its oscillator and clock using a PLL (Phase Locked Loop). Alternatively, each base station may be equipped with a high-precision atomic clock, and synchronization may be adjusted less frequently.

[0043] The base station-terminal synchronization unit 120 synchronizes the base station 100 and the terminal 200 (not shown in FIG. 1, see FIG. 2; in the following description, reference numerals will be omitted as appropriate). Specifically, the base station-terminal synchronization unit 120 synchronizes the base station 100 and the terminal 200 via wireless communication. A synchronization signal is incorporated into the wireless signal at a fixed frequency to reconfirm synchronization. Since each base station is synchronized, it is sufficient for a terminal to synchronize with one base station.

[0044] The measurement unit 130 measures the reception time, amplitude, and phase of a reference wave transmitted from a terminal 200 (which may be any of a plurality of terminals) received by a plurality of base stations 100. Specifically, the measurement unit 130 measures the reception time, amplitude, and phase of a signal received via an antenna (not shown). To measure the signal waveform, internal elements such as an amplifier, a band-pass filter, a sampler, and an analog-to-digital converter are used. The reception time is synchronized by a master clock and is made into a discrete time, and can be realized by counting with a counter from a reference start time.

[0045] The information recording unit 140 can be realized by storing signals output from an analog-to-digital (A / D) converter and a counter in a memory.

[0046] The time adjustment unit 150 imparts a specific time delay to the information on the reception time, amplitude, and phase of the signal measured by the measurement unit 130. Specifically, the time adjustment unit 150 can calculate complex delay amounts and achieve real-time high-speed tracking by using a computer that specifies the desired amount of time delay and a D flip-flop delay circuit.

[0047] The time adjustment unit 150 can adjust the transmission timing of signals from multiple base stations by utilizing the difference in arrival time due to the different distances between the multiple base stations and a specific terminal, so that the signals overlap with a time delay at the position of the specific terminal, forming a convolutionally coded signal.

[0048] In this case, time adjustment section 150 may adjust the time delay required for trellis coding modulation in which redundant bits generated by convolutional coding are assigned to multiple levels of modulation. Furthermore, when there is little uplink data to be transmitted from terminal 200 to base station 100 and base station 100 transmits the same data to multiple terminals 200, time adjustment unit 150 may lengthen the time period of the signal so that the difference in arrival time due to differences in distance from base station 100 to terminal 200 is sufficiently small compared to the change in signal over time.

[0049] The waveform converter 160 converts the output waveform from the time adjuster 150 into a specific waveform based on the output waveform. Specifically, the waveform converter 160 is also used by the base station 100 to connect a specific terminal 200 with another terminal 200 and relay a signal.

[0050] Because the location of each terminal and the radio wave environment of the spatial transmission path between base stations are different, the waveforms will differ even when the same reference waveform is sent and received. Changes in the terminal's location or radio wave environment are slow enough compared to the propagation time of radio waves that if the base station matches the waveforms and transmits them immediately, they will automatically reach the target terminal. Strictly speaking, the signal will reach other terminals as well, but because the phases do not match, the waveforms will be destroyed and will not become a signal. On the other hand, for the target terminal, the phases overlap constructively, increasing the electric field strength, allowing communication.

[0051] The waveform conversion unit 160 can be realized by outputting the corresponding waveform when the waveform pattern matching evaluation exceeds a threshold. Due to the high redundancy of the radio wave hologram (hereinafter simply referred to as hologram), even if waveform conversion at some base stations is not working properly, the system as a whole will function robustly as long as waveform conversion at other base stations is working properly.

[0052] Furthermore, the waveform conversion unit 160 can generate a first inverted waveform by inverting the waveform time over the time range until the arrival of the reference wave is completed at the base station that is farthest from the specific terminal 200 (first terminal) among multiple base stations that receive the reference wave transmitted from the specific terminal 200 (first terminal).

[0053] Furthermore, the waveform converter 160 can generate a second inverted waveform by inverting the time of the waveform over a time range until the arrival of the reference wave is complete at the base station from which the terminal 200 (second terminal) is farthest among multiple base stations that receive a reference wave transmitted from a specific terminal 200 (second terminal different from the first terminal).The waveform converter 160 may convert the first inverted waveform to the second inverted waveform by associating the first inverted waveform with the second inverted waveform when transmitting a signal from the first terminal to the second terminal.

[0054] The transmitting unit 170 transmits a signal in accordance with the output waveform from the waveform converting unit 160. Specifically, the transmitting unit 170 may be composed of an antenna with wide directivity or omnidirectionality that can transmit radio waves over an entire area, rather than a narrow directivity that concentrates radio waves on a specific terminal 200, and a power amplifier.

[0055] When transmitting a signal according to the output waveform from the waveform converter 160, the transmitter 170 may perform parallel redundant communication via multiple routes between a specific terminal 200 (first terminal) and multiple base stations.

[0056] Furthermore, the transmitting unit 170 can transmit a signal in which at least one of the carrier and subcarrier frequencies is multiplexed.

[0057] Furthermore, the transmitter 170 can transmit a signal multiplexed by two orthogonal linear polarizations, or the transmitter 170 can transmit a signal multiplexed by left- and right-handed rotating circular polarizations.

[0058] A radio wave hologram communication device is configured by preparing a large number of base stations having the above-described configuration.

[0059] (2) Connection configuration between base station and terminal 2 is a diagram showing an example of a connection configuration between base station 100 and terminal 200. The clocks of each base station are synchronized via a high-speed optical fiber line.

[0060] Although the connections in Figure 2 are loop-shaped, a star-shaped connection is also possible. The range of synchronization does not need to be the entire area at once, but rather can be hierarchically organized, ranging from small units such as factories, schools, and stadiums, to medium-sized units such as residential areas, and large units such as municipalities, and adaptive processing can be performed according to the purpose.

[0061] 2 shows three terminals, each of which may establish synchronization with a nearby base station. Focusing on one of the terminals 200 (top), the signal radio waves (abbreviated as signals or radio waves as appropriate) emitted from the many base stations 100 are controlled in amplitude and phase to cause constructive interference at the terminal's location, so the electric field strength after propagation automatically becomes strong at the terminal's location.

[0062] (3) Relationship between base station and terminal in time reversal holography Figure 3 shows an example of the relationship between a base station and a terminal in time-reversal holography. The upper part of Figure 3 explains the case where a reference wave is transmitted from a terminal to each base station. The amplitude decreases and the phase rotates depending on the distance to the base station, and this information is measured and stored at each base station.

[0063] If there is a structure that disturbs the radio waves during propagation, or if there is a change in the dielectric constant of the medium (shown as a rectangular parallelepiped in the diagram), the amplitude and phase of the radio waves that pass through that area will differ from those in free space. In free space, the phase is determined by distance, so it can be calculated in advance, but in a real environment, unpredictable disturbances can occur.

[0064] The time change of the phenomenon that causes the disturbance is sufficiently slow compared to the propagation time of the radio waves, so the disturbance characteristics of the electromagnetic waves are maintained even if they are time-reversed. If a base station re-emits radio waves with the time-reversed received waveform in sync with another base station, the disturbance is reversed and the original waveform is reproduced at the location of the terminal that originally emitted the radio waves (bottom of Figure 3). Although the waveform is time-reversed, the information can be restored to its original state, making it possible to overcome the adverse effects of the disturbance and achieve communication. Furthermore, the added redundancy of the hologram enables communication that is extremely resistant to disturbances.

[0065] Figure 4 explains the function of the waveform converter in time-reversal holography. Here, A, B, C, E, F, and G are terminals, and we consider the case where B and F communicate with each other.

[0066] D is a waveform converter installed in the base station. Although not shown in Figure 4 to avoid complexity, it is assumed that there are many other base stations, each of which emits radio waves to the terminal.

[0067] H and I are disturbance factors along the propagation path. As explained in Figure 3, communication between B and the base station is possible by overcoming the disturbances through time reversal. The same is true between F and the base station. D functions to exchange waveforms containing disturbances received from B and F. In other words, when it receives the waveform on the left side of D, it converts it to the waveform on the right side of D and immediately re-radiates it over the entire area, automatically reproducing the original reference waveform at position F. At terminals A, C, E, and G other than the terminal of interest, the phase of the radio wave hologram does not match, so it becomes white noise and also has a channel selection function.

[0068] Figure 5 is a diagram illustrating the time transition of time-reversal holography. The horizontal axis represents the passage of time, and the asymmetric hexagon represents the amplitude of the signal.

[0069] The upper part of Figure 5 shows the case where the distance between the terminal and the base station is the shortest, and the radio waves arrive quickly. The lower part of Figure 5 shows the case where the distance between the terminal and the base station is longer, and the propagation path is a circuitous one, or there are various disturbances with a high dielectric constant that slow down the propagation speed, and it takes longer for the radio waves to arrive at the base station.

[0070] The arrival times vary depending on the path, and the phase-shifted waveforms overlap, causing waveform distortion. While waiting for the radio waves from all paths to arrive, the waveform continues to be recorded. Then, a time-reversed waveform is generated by symmetrically reversing the time at a certain point and re-radiating it from the base station antenna. The waveform dispersed by the disturbance is reshaped into a time-reversed waveform with the same information as the original waveform, as if going back in time.

[0071] Here, we explain the mathematical model for time-reversal holography.

[0072]

number

[0073]

number

[0074] Figure 6 shows an example of the circuit configuration of a time adjustment unit for time reversal holography. Signals received via the antennas of each base station pass through a circulator, undergo A / D conversion, and are stored in a receiving memory.

[0075] Next, the data passes through a gated delay circuit to adjust the delay time. When writing to the memory for transmission, the memory addresses are swapped so that the last recorded data is read out first from the D / A, and the data sequence is time-reversed.

[0076] The D / A reads the time-reversed data, converts it into an analog value, and inputs it into the circulator. The circulator outputs a time-reversed signal, which is then emitted from the same antenna as when it was received. N From (t), radio waves that have undergone similar processing are emitted, and the phase of the radio waves aligns at the position of the terminal that first emitted the radio waves, causing constructive interference.

[0077] (4) Simulation Next, we verify the above-mentioned operation by numerical simulation. Figure 7 shows an input image of the terminal position distribution for the numerical simulation.

[0078] Let's say that the electric field strength is distributed in the shape of the letter "R" on a plane where the terminal is located. The reason for choosing the shape of "R" is that it contains a variety of elements such as straight lines, right angles, diagonal lines, and circles, and it has no symmetry, so the characteristics can be investigated in a general way. The total number of pixels (number of terminals) is 128 x 128, and the sampling interval between terminals is 0.1 m.

[0079] Figure 8 shows the distribution of holograms on a plane where a base station is located to obtain the distribution shown in Figure 7. The left side of Figure 8 shows the case where the distance between the terminal plane and the base station plane is 200 m, and the right side of Figure 8 shows the case where the distance is 500 m. Note that 256 x 256 base stations are arranged at equal intervals on the base station plane. The interval between each base station is 0.1 m, and the carrier frequency is 30 GHz (wavelength 0.01 m).

[0080] Figure 9 shows the electric field intensity distribution that occurs at the terminal surface when the base station emits radio waves according to this hologram. Specifically, Figure 9(b) shows the image reconstructed from the hologram on the left side of Figure 8 when the distance (z, omitted below) is 200 m, and Figure 9(c) shows the image reconstructed from the hologram on the right side of Figure 8 when the distance is 500 m. Figures 9(a) and (d) show images reconstructed from holograms designed for distances of 100 m and 1000 m, respectively.

[0081] As shown in Figures 9(a) to (d), the closer the distance, the clearer the reconstructed image. Note that even in the area where the image is formed in the shape of an "R," points of strong and weak electric fields appear randomly. This is called speckle, a phenomenon unique to holograms. Because the carrier wave, which oscillates according to a trigonometric function, is a periodic function, there are places where the phases coincidentally match (or do not match).

[0082] This effect is particularly significant when there are a limited number of base stations. This problem can be solved by chirping, which sweeps the carrier frequency in a short period of time, as the speckle also moves, making it possible to equalize the time average. Alternatively, the time average can be made uniform by preparing multiple sets of initial phases for the radio waves emitted from each base station and switching them quickly.

[0083] In the simulation, when the hologram is first generated, the initial phase of the reference radio wave from each terminal is not all made the same, but is randomized to prevent the generation of peculiar wavefronts (such as plane waves).

[0084] Figure 10 shows the time transition over 10 periods of the distribution of electric field strength reproduced on a plane where a terminal is located when radio waves are emitted simultaneously from base stations. Figure 9 shows the reproduced image after sufficient time has passed, but since the distance between each terminal and each base station varies depending on the location, the radio waves arrive sequentially from the closest point.

[0085] Therefore, a finite amount of time is required for the desired electric field distribution to form on the terminal plane. Figure 10 shows a simulation of this transient state. The carrier phase was divided into π / 4 intervals, and the simulation was carried out for 10 periods.

[0086] At first, only radio waves arrive from nearby base stations, resulting in low contrast, but as time passes, the number of arriving radio waves increases, making the image clearer and the field strength stronger. Due to the redundancy of the hologram, the field distribution is formed at a fairly early stage, even if not all radio waves arrive. This suggests that it will still function even if only nearby base stations are used, reducing the number of base stations employed. Using a hologram does not require waiting until the end of the transient state, allowing for high-speed communication.

[0087] Therefore, if the baseband signal is sufficiently slower than the carrier frequency, this transient phenomenon does not become a problem, and it is possible to broadcast the same information to an unspecified number of devices in a limited area at the same time, for example, in an advertisement. Even in this case, since the spatial distribution of the electric field can be controlled, it is possible to prevent the signal from reaching areas with low device density or areas where radio waves are not desired.

[0088] Figure 11 shows the time evolution of the PSNR (Peak Signal-to-Noise Ratio) of the distribution of electric field strength reproduced on a plane where a terminal is located. PSNR was adopted as an index to evaluate the degree to which the electric field strength distribution reproduced on the terminal surface matches the target image (original image). The PSNR is defined as follows:

[0089]

number

[0090] PSNR is an index commonly used in image evaluation and is expressed in decibels (dB). The higher the PSNR value, the smaller the difference between the image and the comparison image. Here, N x , N y are the number of pixels in the x and y directions, respectively, and correspond to the number of sampling pixels on the terminal surface (128 pixels).

[0091] E oji is the electric field strength at the coordinate position of index i in the x direction and index j in the y direction on the device surface. E Rji is the electric field strength at the coordinate point (j, i) of the target electric field distribution. The numerator 255 is the maximum density value of the 8-bit resolution image. The distribution image of the electric field strength on the device surface was normalized so that the minimum value is 0 and the maximum value is 255. However, during calculation, it is treated as a real number (8-byte precision) and not quantized to 8 bits (Unsigned Char). In other words, the evaluation is performed without quantization error.

[0092] The target image (original image) used as the reference is the letter "R" shown in Figure 7, with the letter part being represented in white with a pixel value of 255, and the other black parts having a pixel value of 0. A hologram was designed to produce this image, and reconstruction was performed from that hologram. First, this image was read as an unsigned char (1 byte), and subsequent calculations were performed with double (8 byte) precision.

[0093] Looking at the graph in Figure 11, we can see that the PSNR is almost saturated after 7.5 cycles, so there is no need to wait any longer.

[0094] PSNR is a method of comparing two images at the same pixel position. Even if a spatially averaged image, like what the human eye sees, is good, if the position of the reconstructed image is shifted or noise is mixed in, the value will drop significantly.

[0095] Therefore, as another evaluation method, SNR (Signal to Noise Ratio) was defined as follows and used for evaluation. The reconstructed image was masked with the coordinate points containing the letter R in the original image, and the ratio of the average pixel density between the area inside the mask and the area outside the mask was evaluated as SNR. The average pixel density is the sum of the pixel values ​​within an area (for example, within the mask) divided by the number of pixels within that area. The SNR evaluation formula is shown below.

[0096]

number

[0097] Here, E_R is the electric field at the pixel positions (inside the mask) where the letter "R" is written in the target image. E_R￣ is its complement, and is the electric field at all other pixel positions (outside the mask) where "R" is not written. N_R is the number of pixels with "R" written in them, which is 1662 in this case. Its complement, N_R￣, is 14722. N_R+N_R=128^2.

[0098] Figure 12 shows the time evolution of the SNR of the distribution of field strength reproduced on a plane where a terminal is located. This shows that the SNR is almost saturated after 5 cycles. This is also an indicator for determining the number of base stations.

[0099] Figure 13 shows the change in the reconstructed image when the wavelength is shifted by ±10% from the center wavelength λ = 0.01 m, which corresponds to a modulation depth of 10% in FSK (Frequency Shift Keying).

[0100] Specifically, Fig. 13(a) shows λ = 0.009 m with a -10% shift, Fig. 13(b) shows λ = 0.01 m with the design wavelength, and Fig. 13(c) shows λ = 0.011 m with a +10% shift. The period is 4 to 5 cycles after reaching the shortest point, and the time interval between each frame is T / 8 = 1.47 ps.

[0101] As shown in Figure 13, even when the wavelength is shifted by 10%, the distribution of the letter R is still visible, albeit unclear. With PSK (Phase Shift Keying), the spread of the frequency spectrum is small, so it is clear that electric field distribution can be formed without any problems even with modulated radio waves.

[0102] In addition, the position of the speckle bright spot also changes when the wavelength is shifted, so it can be seen that the problem of speckle can be solved by frequency chirping. In addition, since the spectrum of actually modulated radio waves changes sequentially, the speckle naturally moves and is averaged out.

[0103] Figure 14 shows a comparison of the distribution of electric field strength reproduced on the plane of a terminal when the number of base stations is reduced to one-fourth. Figure 14(a) shows the case when all base stations are used, and Figure 14(b) shows the electric field distribution on the terminal plane when only the base stations in the area of ​​the bottom-left quarter of the frame are used.

[0104] Although the electric field strength is weaker in the farther away quarter of the signal used, it can be seen that the entire letter R is reproduced. The PSNR was 11.35 dB in Figure 14(a) and 10.87 dB in Figure 14(b). In a hologram, each base station and each terminal are tightly coupled, and each is connected to the whole. If only part of the hologram is used, uncertainty increases, but even a partial hologram contains information about the whole. This provides high redundancy, and even if communication in one part becomes poor, other parts will compensate.

[0105] The time-reversal method is effective for one-to-one communication between one base station and one terminal, but by combining it with the superposition of multiple routes using holograms, it is possible to realize a communication environment with even higher fault tolerance. This feature is an effective method for overcoming the physical difficulties of electromagnetic wave propagation due to the increasing carrier frequency.

[0106] (5) Convolutional coding using time delay Figure 15 is an explanatory diagram of convolutional coding that uses time delays from equidistant regions. A linear region with a finite width, shown as a circle (or ellipse) on the surface of a base station where hologram data is stored, is an area that is equidistant from the target terminal. When radio waves are emitted from a base station located on the line of this circle, they arrive at the target terminal at the same time.

[0107] In Figure 15, three circles are shown as an example, and the second circle is one wavelength (λ) farther away from the innermost circle, so it will arrive one cycle later. The third, outermost circle is two wavelengths (2λ) farther away, so it will arrive two cycles later.

[0108] Therefore, if the third base station group emits radio waves first, the second base station group emits radio waves one cycle later, and then the base station group in the innermost circle emits radio waves two cycles later, the radio waves will arrive at the target device at the same time and be superimposed. This can be interpreted as being equivalent to a convolution operation, as the data is added with a time lag.

[0109] Convolution is a method of correlating the current and past data of a station to separate high-probability transitions from low-probability transitions, making it easier to extract signals from signals mixed with noise. By emitting signals encoded for each degree of the circle, the terminal can simultaneously perform error correction by decoding the time-series signal using software or hardware.

[0110] Although the area of ​​the concentric lines is not large compared to the whole area, it still constitutes a partial area hologram, which allows for spatial selectivity, making it possible to send signals only to specific terminals.

[0111] (6) Trellis-coded modulation using time delay 16 is an explanatory diagram of trellis coded modulation using time delays from equidistant regions. Specifically, it shows a multilevel signal expressed in signal space, for the case of 8PSK.

[0112] In Figure 15, for simplicity, the convolution operation is performed in units of one period, but it is possible to perform the convolution operation even if the phase is divided into smaller units of π / 8, for example. This expands the Euclidean distance in signal space, making it possible to incorporate error correction into the signal. In the figure, the lower two bits of the three bits are italicized, but it is advisable to apply the convolution operation using an equidistant partial hologram to the lower two bits, which have a small phase difference and are prone to errors.

[0113] (7) Actions and Effects of the Embodiments As described above, the radio wave hologram communication device and radio wave hologram communication method of this embodiment enable stable communication to be established even in an unstable radio wave environment due to the redundancy of the hologram, and the radiation pattern can be instantly changed so that radio waves reach only the area where the terminal is located.

[0114] On the other hand, the signal acts as noise and does not reach other devices, providing security at the physical layer, and the time-reversal hologram allows the waveform to be reconstructed even if disturbances occur. In addition, the convolution operation using time differences can be performed automatically at the speed of light while the radio waves are propagating, greatly contributing to the reliability, controllability, and efficiency of high-frequency wireless communications.

[0115] Furthermore, with the radio wave holographic communication device and radio wave holographic communication method according to the above-described embodiment, service areas are designed by intentionally causing interference between radio waves emitted from multiple geographically adjacent base stations. This intentional interference is controlled by radio wave holographic technology, making it possible to provide service areas of any shape that have not been possible until now. Furthermore, the ability to configure service areas of any shape makes it possible to provide services that require interference control. Traffic allocation to users can also be selectively performed.

[0116] (8) Other embodiments The present invention has been described above with reference to the examples, but it will be obvious to those skilled in the art that the present invention is not limited to these examples and that various modifications and improvements are possible.

[0117] For example, in the above-described embodiment, the base station 100 includes the information recording unit 140, but the base station 100 does not necessarily have to include the information recording unit 140. That is, the base station 100 may store information on the reception time, amplitude, and phase of the received signal measured by the measurement unit 130 not in the information recording unit 140 but temporarily and / or virtually within the communication system.

[0118] Furthermore, it is not necessary to impart a time delay to all of the information on the reception time, amplitude, and phase, but a time delay may be imparted to only one or two of them.

[0119] The block diagram (FIG. 1) used to explain the above-described embodiment shows functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. The method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are connected directly or indirectly (for example, by wire, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining the single device or multiple devices with software.

[0120] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how each is implemented.

[0121] Furthermore, the above-described base station 100 and terminal 200 (including a radio wave hologram communication device, hereinafter referred to as the device) may function as a computer that performs processing of the wireless communication method of the present disclosure. FIG. 17 is a diagram showing an example of the hardware configuration of the base station 100 and terminal 200. As shown in FIG. 17, the device may be configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0122] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0123] Each functional block of the device (see FIG. 1) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0124] In addition, each function of the device is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication via communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0125] The processor 1001 controls the entire computer by running, for example, an operating system, and may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, a register, and the like.

[0126] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-mentioned embodiments. Furthermore, the various processes described above may be executed by one processor 1001, or may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0127] The memory 1002 is a computer-readable recording medium and may be configured by, for example, at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 can store a program (program code), a software module, etc., that can execute a method according to an embodiment of the present disclosure.

[0128] Storage 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, a database, a server, or other appropriate medium including at least one of memory 1002 and storage 1003.

[0129] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0130] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize, for example, at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

[0131] The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0132] Furthermore, each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0133] Furthermore, the device may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0134] Each aspect / embodiment described in the present disclosure may be applied to at least one of a system using Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, a 4th generation mobile communication system (4G), a 5th generation mobile communication system (5G), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable system, and a next-generation system extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A and 5G) may also be applied.

[0135] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0136] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, notification of predetermined information (e.g., notification that "X is true") is not limited to being done explicitly, but may be done implicitly (e.g., by not notifying the predetermined information).

[0137] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0138] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0139] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0140] Note that terms explained in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0141] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0142] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0143] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0144] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0145] The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0146] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0147] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0148] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, or the mobile object itself. The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0149] Furthermore, a base station in the present disclosure may be interpreted as a mobile station (user terminal, the same applies hereinafter). For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the mobile station may be configured to have the functions of a base station. Furthermore, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to communication between terminals (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be interpreted as a side channel (or side link).

[0150] Similarly, a mobile station in the present disclosure may be interpreted as a base station, in which case the base station may have the functions of a mobile station.

[0151] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0152] The reference signal may also be abbreviated as Reference Signal (RS), and may also be called a pilot depending on the applicable standard.

[0153] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0154] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0155] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

[0156] When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Furthermore, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0157] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0158] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0159] In the present disclosure, the term "A and B are different" or "A and B are different from each other" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0160] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure. [Explanation of symbols]

[0161] 100 base stations 110 Inter-base station synchronization unit 120 Base station inter-terminal synchronization unit 130 Measurement Unit 140 Information Recording Unit 150 Time adjustment unit 160 Waveform conversion section 170 Transmitter 200 devices 1001 processor 1002 memory 1003 Storage 1004 Communication equipment 1005 Input Device 1006 Output Device 1007 Bus

Claims

1. an inter-base station synchronization unit that synchronizes the phases of carrier waves transmitted from a plurality of base stations; a base station-terminal synchronization unit that synchronizes the base station and a terminal; a measurement unit that measures the reception time, amplitude, and phase of a reference wave transmitted from the terminal and received by the plurality of base stations; a time adjustment unit that imparts a specific time delay to the information on the reception time, the amplitude, and the phase measured by the measurement unit; a waveform conversion unit that converts the output waveform from the time adjustment unit into a specific waveform based on the output waveform from the time adjustment unit; a transmitter that transmits a signal according to the specific waveform; Equipped with the waveform converter sets the output waveform to a first inverted waveform obtained by time-inverting a waveform over a time range until arrival of the reference wave is completed at the base station from which the first terminal is farthest among the plurality of base stations that receive the reference wave transmitted from the first terminal, and the transmitting unit performs parallel redundant communication between the first terminal and the plurality of base stations via multiple routes; Radio wave holographic communication device.

2. The waveform converter is the output waveform is a second inverted waveform obtained by inverting the waveform in time over a time range until the arrival of the reference wave is completed at the base station from which the second terminal is farthest among the plurality of base stations that receive the reference wave transmitted from the second terminal, By associating the first inverse waveform with the second inverse waveform, when transmitting a signal from the first terminal to the second terminal, the first inverse waveform is converted into the second inverse waveform.

2. The radio wave hologram communication device according to claim 1.

3. the time adjustment unit utilizes arrival time differences due to differences in distance between the plurality of base stations and the terminal, and adjusts transmission timings of signals from the plurality of base stations so that signals overlap with a time delay at the position of the terminal, thereby forming a convolutionally coded signal.

2. The radio wave hologram communication device according to claim 1.

4. the time adjustment unit adjusts the time delay required for trellis coding modulation in which redundant bits generated by convolutional coding are assigned to multiple modulation values; 4. The radio wave hologram communication device according to claim 3.

5. when the amount of uplink data transmitted from the terminal to the base station is small and the same data is transmitted from the base station to a plurality of the terminals, the time adjustment unit lengthens the time period of the signal so that a difference in arrival time due to a difference in distance from the base station to the terminal becomes sufficiently small with respect to a change in the signal over time; 2. The radio wave hologram communication device according to claim 1.

6. the transmitting unit transmits a signal in which at least one of a carrier frequency and a subcarrier frequency is multiplexed; 2. The radio wave hologram communication device according to claim 1.

7. The transmitter transmits a signal multiplexed by two orthogonal linearly polarized waves.

2. The radio wave hologram communication device according to claim 1.

8. The transmitter transmits a multiplexed signal using left and right rotating circular polarization.

2. The radio wave hologram communication device according to claim 1.

9. synchronizing the phases of carrier waves transmitted from a plurality of base stations; synchronizing the base station and the terminal; measuring the reception time, amplitude, and phase of a reference wave transmitted from the terminal received by a plurality of the base stations; providing a specific time delay to the measured information of the reception time, the amplitude, and the phase; converting the output waveform to a specific waveform based on the time-delayed output waveform; transmitting a signal according to the particular waveform; Including, In the step of converting the waveform, the output waveform is set to a first inverted waveform obtained by inverting the waveform over a time range until arrival of the reference wave is completed at the base station from which the first terminal is farthest among the plurality of base stations that receive the reference wave transmitted from the first terminal, and the transmitting step performs parallel redundant communication between the first terminal and a plurality of the base stations via a plurality of routes; Radio wave holographic communication method.

10. In the step of converting the waveform, the output waveform is a second inverted waveform obtained by inverting the waveform in time over a time range until the arrival of the reference wave is completed at the base station from which the second terminal is farthest among the plurality of base stations that receive the reference wave transmitted from the second terminal, By associating the first inverse waveform with the second inverse waveform, when transmitting a signal from the first terminal to the second terminal, the first inverse waveform is converted into the second inverse waveform.

10. The radio wave holographic communication method according to claim 9.

11. In the step of providing a time delay, a difference in arrival time due to differences in distance between the plurality of base stations and the terminal is utilized, and transmission timings of signals from the plurality of base stations are adjusted so that the signals overlap with a time delay at the position of the terminal, thereby forming a convolutionally coded signal.

10. The radio wave holographic communication method according to claim 9.

12. In the step of providing the time delay, a time delay required for trellis coding modulation in which redundant bits generated by convolutional coding are assigned to multiple modulation values ​​is adjusted. The radio wave holographic communication method according to claim 11.

13. In the step of providing the time delay, when the amount of uplink data transmitted from the terminal to the base station is small and the same data is transmitted from the base station to a plurality of the terminals, the time period of the signal is lengthened so that the difference in arrival time due to the difference in distance from the base station to the terminals becomes sufficiently small compared to the change in the signal over time.

10. The radio wave holographic communication method according to claim 9.

Images