Data processing device and data processing method

Abstract

The present technology relates to a data processing device and a data processing method that make it possible to reduce a process pertaining to demodulation. The present invention comprises: a reception signal generation unit that generates a reception signal for each beam generated by digital beamforming; an interference amount calculation unit that uses the reception signal generated by the reception signal generation unit to calculate the amount of interference with a reception desired signal; a reception success rate calculation unit that calculates a reception success rate at which the reception of a signal from a reception target terminal has been successful; a beam selection unit that selects a beam for which the reception success rate calculated by the reception success rate calculation unit is high; and a demodulation unit that uses data which has been received with the beam selected by the beam selection unit to perform demodulation. The present technology can be applied to, for example, a data processing device that is mounted in a satellite reception station.

Description

Data processing device and data processing method

[0001] The present technology relates to a data processing device and a data processing method, and more particularly to a data processing device and a data processing method suitable for use in a system to which IoT technology is applied, for example.

[0002] 2. Description of the Related Art Wireless technologies that enable long-distance one-way (from a transmitting terminal to a receiving station) communication have been proposed as communication technologies for the Internet of Things (IoT) (see, for example, Patent Document 1).

[0003] It has been proposed that a beam be formed and transmitted toward a ground station based on location information, and that the ground station also have an array antenna unit, and that communication be continued by both the aircraft and the ground station performing beamforming (see, for example, Patent Document 2).

[0004] Patent No. 6259550 Patent Publication No. 2014-207626

[0005] IoT technology can also be applied to mobile terminals. Because mobile terminals may transmit information from locations that are subject to interference, it is desirable to reduce the effects of interference so that reception can be achieved. When beamforming is used to reduce the effects of interference, demodulation must be performed for each of multiple beams, which may increase the time, capacity, and cost required for the demodulation process. It is desirable to reduce the processing required for demodulation when beamforming is used.

[0006] The present technology has been made in view of such circumstances, and is capable of reducing the processing involved in demodulation.

[0007] A data processing device according to one aspect of the present technology is a data processing device that includes a reception signal generation unit that generates a reception signal for each beam generated by digital beamforming, an interference amount calculation unit that calculates the amount of interference interfering with a desired reception wave using the reception signal generated by the reception signal generation unit, a reception success rate calculation unit that calculates the reception success rate at which signals from a target terminal are successfully received, a beam selection unit that selects a beam with a high reception success rate calculated by the reception success rate calculation unit, and a demodulation unit that demodulates data received by the beam selected by the beam selection unit.

[0008] A data processing method according to one aspect of the present technology is a data processing method in which a data processing device generates a received signal for each beam generated by digital beamforming, calculates the amount of interference interfering with a desired reception signal using the generated received signal, calculates a reception success rate at which signals from a target terminal are successfully received, selects a beam with a high calculated reception success rate, and demodulates data received by the selected beam.

[0009] In a data processing device and data processing method according to one aspect of the present technology, a received signal is generated for each beam generated by digital beamforming, the generated received signal is used to calculate the amount of interference interfering with the desired reception wave, the reception success rate at which signals are successfully received from the target terminal is calculated, the beam with the calculated high reception success rate is selected, and demodulation is performed using the data received by the selected beam.

[0010] The data processing device may be an independent device or an internal block constituting one device.

[0011] FIG. 1 is a diagram for explaining a configuration example of an embodiment of a data processing system to which the present technology is applied. FIG. 2 is a diagram for explaining control of beam width. FIG. 3 is a diagram for explaining a configuration example of an antenna unit. FIG. 4 is a diagram for explaining a configuration example of a received signal generation unit. FIG. 5 is a diagram for explaining a beam shape. FIG. 6 is a diagram for explaining a configuration example of a satellite receiving station. FIG. 7 is a flowchart for explaining processing related to demodulation. FIG. 8 is a flowchart for explaining a reception success rate calculation process. FIG. 9 is a diagram for explaining calculation of interference amount. FIG. 10 is a diagram for explaining how to arrange virtual terminals. FIG. 11 is a diagram for explaining an example of a table in which reception success rates are recorded. FIG. 11 is a diagram for explaining a configuration example of a PC.

[0012] Hereinafter, modes for carrying out the present technology (hereinafter referred to as embodiments) will be described.

[0013] <Configuration of Data Processing System> The present technology can be applied to a data processing system using the Internet of Things (IoT), and therefore, the present technology will be described here using such a system as an example.

[0014] 1 is a diagram showing the configuration of an embodiment of a data processing system to which the present technology is applied. The data processing system 1 includes a satellite receiving station 11 and transmitting terminals 21-1 to 21-3. The satellite receiving station 11 receives and processes data transmitted at predetermined intervals from the transmitting terminals 21-1 to 21-3. IoT technology can be applied to the data processing system 1.

[0015] With IoT, information is acquired from transmitting terminals 21-1 to 21-3 installed in mountainous areas or at sea, where it was previously difficult to acquire information. Observations based on the acquired information are expected to enable the understanding of environmental changes and the prevention of disasters. However, the installation of receiving stations has been an issue. Since it is expected that there will be fewer terminals in mountainous areas than in urban areas, there have been concerns that the cost of installing and operating receiving stations for the few terminals will be high. There have also been concerns that installing receiving stations at sea would be difficult.

[0016] Therefore, a wireless system is constructed that mainly uses a satellite receiving station 11 mounted on a low-earth orbit satellite, as in the data processing system 1 shown in Fig. 1. The use of the satellite receiving station 11 makes it possible to provide wireless technology for IoT that enables long-distance communication. It is also possible to construct a wireless system that combines a terrestrial receiving station and the satellite receiving station 11, making it possible to obtain information from anywhere on Earth at low cost.

[0017] Since the satellite orbit of a low-earth orbit satellite is approximately 400 km above sea level, the reception range is very wide when a normal receiving antenna is used. As a result, many interference signals other than the desired signal are received, which can deteriorate the signal-to-noise ratio (SNR) of the received signal and make communication difficult. The conical receiving antenna range in Figure 1 indicates the range where a certain level of antenna gain can be obtained with the receiving antenna mounted on the satellite receiving station 11. For example, this indicates the range where the peak receiving antenna gain is reduced by 3 dB.

[0018] 1 also shows interference sources 23-1 to 23-3. Interference sources 23-1 to 23-3 are terminals that emit radio signals that become interference sources when receiving radio signals from transmitting terminals 21-1 to 21-3. For example, if the 920 MHz band is used for communication between satellite receiving station 11 and transmitting terminals 21-1 to 21-3, the 920 MHz band is shared with other systems, so there is a possibility that transmitting terminals of those other systems will become interference sources.

[0019] 1, the satellite receiving station 11 can receive signals from transmitting terminals 21-1 to 21-3 located within the range of the receiving antenna as desired waves, but also receives signals from interference sources 23-1 to 23-3. Receiving signals other than desired waves, in this case signals from interference sources 23-1 to 23-3, can deteriorate the signal-to-noise ratio of the desired wave signals from transmitting terminals 21-1 to 21-3.

[0020] One method for reducing received interference waves is to narrow the beam width of the receiving antenna of the satellite receiving station 11. A technique called phased array is available as a method for controlling the beam width of a receiving antenna. Phased array is a technology that can narrow the beam width by digitally processing signals received by multiple receiving antennas, and is a highly versatile technology for satellites with size constraints. Furthermore, by changing the digital processing, it is possible to form a beam peak in any direction, and by combining multiple beams, it is also possible to receive signals over a wider area.

[0021] 2A shows a case where a technology called phased array is applied to the receiving antenna of the satellite receiving station 11, the beam width is optimized for the transmitting terminal 21-1, and the beam is controlled so as to be directed toward the transmitting terminal 21. In this case, reception of the desired wave from the transmitting terminal 21-1 is subject to interference from the interference source 23, but because the beam width is narrow, in other words, the range of the receiving antenna is narrow, the amount of interference wave received from the interference source 23 is also small, and the impact of the interference wave can be reduced.

[0022] The example shown in Figure 2B shows a case where the beam width and beam direction are optimized for the transmitting terminal 21-3. In this case, the desired wave from the transmitting terminal 21-3 can be received without interference from any of the interference sources 23-1 to 23-3. The example shown in Figure 2C shows a case where the beam width and beam direction are optimized for the transmitting terminal 21-3. In this case, the desired wave from the transmitting terminal 21-3 can be received without interference from any of the interference sources 23-1 to 23-3.

[0023] By optimizing the beam width for the transmitting terminal you want to receive from, you can achieve good reception with reduced interference waves. We will now explain further why optimizing the beam width can achieve good reception.

[0024] <Regarding Reception Conditions> Here, let us consider the conditions for receiving the wireless signals from transmitting terminals 21-1 to 21-3. Whether or not the wireless signal from transmitting terminal 21 can be received depends on whether or not a certain value of SINR (Signal to Noise Ratio) is obtained. Note that this certain value is determined by the wireless technology used. SINR can be expressed by the following equation (1).

[0025]

[0026] In equation (1), S is the received power of the transmitting terminal 21, N is the thermal noise power of the satellite receiving station 11, and I is the total received power from the interference source 23. Furthermore, the received power S can be expressed by the following equation (2), and the total received power I can be expressed by the following equation (3).

[0027]

[0028] In equations (2) and (3), P tx is the transmission power of the transmitting terminal 21, G tx is the transmission antenna gain of the transmitting terminal 21, PL is the propagation path loss, and G rx is the receiving antenna gain. The received power S is the value for the transmitting terminal 21 that is the reception target, and the transmitted and received power I is the total from transmitting terminals that exist as interference sources 23 within the reception range.

[0029] From the definition of SINR (Equation (1)), it can be seen that as the amount of interference I increases, the SINR decreases, potentially making reception difficult. Increasing the SINR value is one way to improve reception accuracy. In order to increase the SINR value, it is considered to reduce the amount of interference I. From the definition of interference I (Equation (3)), the only value that can be controlled on the satellite receiving station 11 side is the receiving antenna gain G_rx. The transmission power P tx and the transmitting antenna gain G tx are values ​​controlled on the transmitting terminal 21 side, and the propagation path loss PL is a value that depends on the distance between the transmitting terminal 21 and the satellite receiving station 11. Therefore, in order to control the amount of interference I on the receiving side, it is possible to reduce the receiving antenna gain G rx.

[0030] As explained with reference to Fig. 2, by controlling the beam width and beam direction, it is possible to perform reception with reduced interference from the interference source 23. As shown in Fig. 2, by directing the receiving antenna gain toward the transmitting terminal 21, which is the reception target, and at the same time narrowing the receiving antenna range to reduce the amount of interference from the interference source 23, it is possible to increase the possibility of receiving a signal from the transmitting terminal 21.

[0031] In this way, by controlling the receiving antenna gain G rx on the satellite receiving station 11 side (receiving side), it is possible to control so as to reduce the interference level I and increase the SINR, thereby increasing the possibility of successfully receiving a signal from the transmitting terminal 21.

[0032] <Beam Forming Method> Digital beam forming technology can be applied as a method for controlling the receiving antenna gain G rx on the satellite receiving station 11 side. Digital beam forming will be further explained with reference to FIG.

[0033] Fig. 3A is a diagram showing an example of the configuration of the receiving antenna unit 31 provided in the satellite receiving station 11. The receiving antenna unit 31 has multiple antenna elements 32 on its antenna surface. In the example shown in Fig. 3A, eight antennas, antenna elements 32-1 to 32-8, are provided on the antenna surface. Hereinafter, when there is no need to distinguish between the antenna elements 32-1 to 32-8, they will be simply referred to as antenna elements 32. For example, an omnidirectional antenna can be used as the antenna element 32.

[0034] Here, we will continue the explanation using an example in which eight antenna elements 32 are provided in a 2x4 arrangement, but this description does not imply any limitations on the number or arrangement of the antenna elements 32, and the present technology can be applied to antenna elements 32 with fewer or more than eight elements, or to arrangements other than 2x4.

[0035] FIG. 3B shows the relationship between the antenna plane and incident waves. The illustration shows the case where incident waves are incident on the antenna plane from directions of angles α and β. The angle α represents the angle of the incident wave in the XY plane, and the angle β represents the angle of the incident wave in the YZ plane. The antenna elements 32-1 to 32-8 receive incident waves incident from directions of angles α and β, respectively. The timing at which incident waves incident at such angles, in other words, incident waves incident on the antenna plane from a diagonal right direction in FIG. 3, are received differs among the antenna elements 32-1 to 32-2. For example, the antenna element 32-8 receives the incident wave earlier than the antenna element 32-2.

[0036] A delay in receiving the incident wave means that the signal is received with a corresponding phase shift. By correcting the phase of the digital signals received by the multiple antenna elements 32 appropriately and then adding them together, it becomes possible to control the phases so that they match appropriately when coming from a specific direction, and to form a beam that has the greatest gain in a specific direction.

[0037] As shown in Fig. 4, in digital beamforming, a received signal is generated by multiplying a signal received by each antenna element 32 by a phase in a multiplier 33 and adding the results in an adder 34. The received signal generator 40 shown in Fig. 4 has a multiplier 33-1 that multiplies a signal from antenna element 32-1 provided on the antenna plane of the receiving antenna unit 31 by an appropriate phase, a multiplier 33-2 that multiplies a signal from antenna element 32-2 by an appropriate phase, a multiplier 33-3 that multiplies a signal from antenna element 32-3 by an appropriate phase, and a multiplier 33-4 that multiplies a signal from antenna element 32-4 by an appropriate phase.

[0038] The received signal generating unit 40 also has a multiplier unit 33-5 that multiplies the signal from antenna element 32-5 by an appropriate phase, a multiplier unit 33-6 that multiplies the signal from antenna element 32-6 by an appropriate phase, a multiplier unit 33-7 that multiplies the signal from antenna element 32-7 by an appropriate phase, and a multiplier unit 33-8 that multiplies the signal from antenna element 32-8 by an appropriate phase.

[0039] The received signal generating section 40 has an adding section 34 that adds the outputs from the multiplying sections 33-1 to 33-8. The adding section 34 adds the signals from the multiplying sections 33-1 to 33-8 to generate a received signal.

[0040] Various beams can be formed by the phase multiplied by the multiplier 33 of the received signal generator 40. For example, when forming a beam peak in the direction of the incident wave (α, β) as shown in FIG. 3B, the phase can be determined based on the following equation (4): In equation (4), dx and dy are the spacing between the antenna elements 32, and λ is the wavelength of the carrier wave.

[0041]

[0042] It is also possible to change the number of receiving antennas used for digital beamforming by setting the coefficient of a specific antenna element 32 to zero, for example, by setting the coefficient multiplied by the multiplier 33 of the receiving signal generator 40 shown in FIG. 4 to zero. For example, it is possible to use only four of the eight receiving antennas. It is also possible to change the beam shape by changing the number of receiving antennas used.

[0043] FIG. 5 shows an example of a beam shape that can be formed by digital beamforming using the receiving antenna unit 31 having eight antenna elements 32 in a 2×4 arrangement, for example, as shown in FIG. 3A.

[0044] The vertical direction in Fig. 5 indicates the number of antenna elements 32 used in the format of N x M. This means that N antenna elements 32 are arranged in the X direction and M antenna elements 32 are arranged in the Y direction, with the antenna surface being an XY plane. Fig. 5 shows beam shapes (beam characteristics) that can be formed when two 2 x 1 antenna elements 32 are used, when four 2 x 2 antenna elements 32 are used, when six 2 x 3 antenna elements 32 are used, and when eight 2 x 4 antenna elements 32 are used.

[0045] 3A, when eight 2×4 antenna elements 32 are provided, the beam shape when two 2×1 antenna elements 32 are used is a beam shape that can be formed when the coefficient by which the signals received by six of the eight antenna elements 32 are multiplied is set to 0. Beam shapes of other numbers can also be formed by setting the coefficient by which the signals from unused antenna elements 32 are multiplied to 0.

[0046] Alternatively, as will be described later with reference to Figure 9, an on / off unit 90 may be provided that turns on when data received by the antenna element 32 is to be output to a subsequent stage and turns off when data is not to be output, thereby controlling the number of antenna elements 32 to be used.

[0047] The horizontal direction in Figure 5 indicates the direction in which the beam is directed when the antenna plane is facing the center of the Earth. Figure 5 shows five cases in which the beam is directed in each of five directions: directly below (0,0), forward (0,X), left (90,X), backward (180,X), and right (270,X). X is 20, 40, or 60.

[0048] The horizontal axis of each graph represents the downward angle from the satellite receiving station 11, and the vertical axis represents the receiving antenna gain. For example, from the graph of directly below / (0,0), it can be seen that when the beam is directed directly below, a beam with beam characteristics in which the receiving antenna gain peaks when the downward angle from the satellite receiving station 11 is 0 degrees can be formed.

[0049] One graph of forward / (0,X), for example, forward / (0,X) when two 2×1 antenna elements 32 are used, shows three beam characteristics when X is 20, when X is 40, and when X is 60, and it can be seen that beams with different beam characteristics can be formed. When three beams are shown on one graph in this way, beams with beam peaks at three points away from directly below the satellite receiving station 11 in the relevant direction are shown.

[0050] The beam characteristics obtained from each graph are numbered in order starting from 1. For example, the 2x1 beam characteristic directly below (0,0) is numbered beam 0. Also, for example, of the three 2x1 beam characteristics forward (0,X), beam 4 is numbered for X=20, beam 5 for X=40, and beam 6 for X=60. The beam characteristics shown in FIG. 5 are assigned numbers from 0 to 51.

[0051] 5, when eight antenna elements 32 (2 × 4) are used, when beams are directed in five directions, and when X is set to 20, 40, or 60, 52 beam characteristics from 0 to 51 can be obtained. In order to obtain more beam characteristics, the direction in which the beam is directed can be set to five or more directions, or the value of X can be set to a value other than 20, 40, or 60, thereby obtaining more detailed beam characteristics.

[0052] As shown in an example in FIG. 5, digital beamforming makes it possible to form any beam.

[0053] Since demodulation processing is required for each beam, for example, when receiving processing is performed using beams with 52 beam characteristics as in the example shown in Fig. 5, demodulation processing is required 52 times. Performing demodulation processing using all beams may increase the cost, processing time, and processing capacity required for demodulation processing.

[0054] Furthermore, as mentioned above, signals received by a beam having beam characteristics that are not suitable for the transmitting terminal 21 have a small SINR value, and therefore the reliability of reception accuracy is low, so it is advisable to reduce the cost, processing time, processing capacity, etc. required to demodulate such signals.

[0055] Therefore, below we will explain how to select a beam with beam characteristics that can receive signals with a high SINR value and highly reliable reception accuracy, and demodulate the signals received by such a beam, thereby reducing the cost, processing time, processing power, etc. required for demodulation.

[0056] <Configuration of satellite receiving station> Figure 6 is a diagram showing an example configuration of a satellite receiving station 11 equipped with a data processing device that selects a beam suitable for the transmitting terminal 21 that is the reception target, and demodulates the signal received by the selected beam.

[0057] The satellite receiving station 11 (or the data processing device provided therein) is configured to include a received signal generation unit 40, an interference amount calculation unit 51, a demodulation unit 52, a storage unit 53, and a reception success rate calculation processing unit 60. The received signal generation unit 40 has the configuration shown in Fig. 4 and includes a receiving antenna unit 31, a multiplication unit 33, and an addition unit 34. The receiving antenna unit 31 includes antenna elements 32-1 to 32-8 (Fig. 4), although these are not shown in Fig. 6.

[0058] The reception success rate calculation processing unit 60 includes a terminal position setting unit 71, a radius setting unit 72, a virtual terminal placement unit 73, a reception power calculation unit 74, a reception success number counter unit 75, and a reception success rate calculation unit 76.

[0059] The operation of the satellite receiving station 11 shown in Fig. 6 will be described with reference to the flowcharts shown in Fig. 7 and Fig. 8. The processing of the flowcharts shown in Fig. 7 and Fig. 8 is executed at a predetermined time t, and is processing related to demodulation of a signal from a predetermined transmitting terminal 21.

[0060] In step S11, the position of the satellite receiving station 11 is acquired. The satellite receiving station 11 acquires its own position information based on, for example, operation information of the satellite receiving station 11. The satellite receiving station 11 also identifies its own position using the Global Navigation Satellite System (GNSS), and acquires the identified position as position information.

[0061] In step S12, a beam x to be treated is set. For example, as described with reference to FIG. 5, in a configuration in which 52 beams can be formed, one beam is selected from the group of 52 beams. For example, starting with beam 0, beam 1, beam 2, ... beam 51 are selected in this order. Here, the description will continue assuming that beam 0 is selected.

[0062] In step S13, the received data is stored. In step S14, the amount of interference I(t, x) is calculated. In steps S13 and S14, reception processing is performed using the set beam x, in this case beam 0, and data at time t is acquired and temporarily stored in memory unit 53. The amount of interference I is calculated using the data stored in memory unit 53.

[0063] The calculation of the interference amount I will be described with reference to Fig. 9. Fig. 9 is a diagram showing an example of a configuration related to the calculation of the interference amount I. The configuration related to the calculation of the interference amount I is configured by adding a storage unit 53 and an interference amount calculation unit 51 to the configuration of the received signal generation unit 40 shown in Fig. 5. Data received by each of the antenna elements 32-1 to 31-8 provided in the receiving antenna unit 31 is stored in storage units 53-1 to 53-8.

[0064] Data received by antenna element 32-1 is stored in storage unit 53-1, data received by antenna element 32-2 is stored in storage unit 53-2, data received by antenna element 32-3 is stored in storage unit 53-3, data received by antenna element 32-4 is stored in storage unit 53-4, data received by antenna element 32-5 is stored in storage unit 53-5, data received by antenna element 32-6 is stored in storage unit 53-6, data received by antenna element 32-7 is stored in storage unit 53-7, and data received by antenna element 32-8 is stored in storage unit 53-8.

[0065] The data stored in each memory unit 53 is supplied to the multiplication unit 33 via an on / off unit 90. Information on the set beam x is supplied to the on / off unit 90. The on / off unit 90 connected to the memory unit 53 corresponding to the antenna elements 32 necessary to form the beam x is turned on, and the on / off unit 90 connected to the memory unit 53 corresponding to the antenna elements 32 not necessary is turned off.

[0066] For example, if the set beam x is beam 0, and when beam 0, antenna elements 32-1 and 32-2 are used, on / off unit 90-1 connected to memory unit 53-1 that stores data from antenna element 32-1 is turned on, on / off unit 90-2 connected to memory unit 53-2 that stores data from antenna element 32-2 is turned on, and on / off units 90-3 to 90-8 connected to memory units 53-3 to 53-8 that store data from antenna elements 32-3 to 32-8, respectively, are turned off.

[0067] Data from the on / off unit 90 that is turned on is supplied to the multiplication unit 33. Phase information of the beam x is supplied to the multiplication unit 33, and the multiplication unit 33 is multiplied by a phase (coefficient) based on the phase information. The output from the multiplication unit 33 is supplied to the addition unit 34, where it is added. The data added by the addition unit 34 is supplied to the interference amount calculation unit 51. The interference amount calculation unit 51 calculates the average power of the added signal for each time, thereby calculating the interference amount I of the corresponding beam at the corresponding time.

[0068] In order to calculate the average power for each time, the storage unit 53 also stores the summation unit 34 calculated at a time before time t. The storage unit 53 stores data for a plurality of times before time t, and the interference amount calculation unit 51 calculates the interference amount I by using this data and the data obtained at time t.

[0069] In step S14, when the interference amount i(t, x) of beam x at time t is calculated, the process proceeds to step S15. In step S15, a reception success rate calculation process is executed. The reception success rate calculation process executed in step S15 will be described with reference to the flowchart of FIG.

[0070] In step S31, a virtual terminal is set. The virtual terminal is a virtual transmitting terminal set within the range where the transmitting terminal 21 is estimated to be located. Setting of the virtual terminal will be described with reference to FIG. 10.

[0071] As shown in A of Fig. 10, the initial location of the target receiving terminal is set by the terminal location setting unit 71 (Fig. 6). The example shown in A of Fig. 10 shows a case where transmitting terminals 21-1 to 21-5 are located as target receiving terminals within the target receiving area (the area represented by a rectangle in the figure). The initial location of each transmitting terminal 21 is set to the initial location registered at the time of contract or the location of the corresponding terminal previously obtained within the system.

[0072] For example, if the transmitting terminal 21 is used in a fixed position, the initial position registered at the time of contract can be used. If the transmitting terminal 21 is included in a mobile device, the position where the transmitting terminal 21 was located when the previous reception success rate calculation process was executed is used as the initial position. The initial position of the transmitting terminal 21 is stored appropriately in the storage unit 53 and read out as needed. Alternatively, initial position information held by another device, for example, another satellite receiving station, may be acquired. Alternatively, it may be acquired from a server on the ground.

[0073] Once the initial position of the transmitting terminal 21 as the target receiving terminal is set, the range in which the transmitting terminal 21 may have moved from that initial position is predicted, as shown in B of Fig. 10. The range in which the transmitting terminal 21 may have moved (hereinafter referred to as the predicted movement range) is determined by a circle with a radius R [km] centered on the initial position. The radius R [km] is calculated using the expected movement speed v [km / h] and the elapsed time T [h] since the last location information update, as follows: R = v × T

[0074] The expected travel speed can be determined, for example, by the terminal type registered at the time of signing the contract. For example, if the terminal type at the time of signing the contract is for vehicle use, the expected travel speed can be set to 60 km / h, if for walking use, it can be set to 4 km / h, and if for stationary use, it can be set to 0 km / h.

[0075] An upper limit for the elapsed time T[h] may be set. For example, the upper limit for the elapsed time T[h] may be set to 12[h]. As the elapsed time T[h] increases, the radius R[km] also increases. Therefore, an upper limit may be set for the elapsed time T[h] to keep the radius R within a certain range.

[0076] FIG. 10B shows the predicted movement range with a circle having a radius set in the radius setting unit 72 (FIG. 6) in this manner.

[0077] Once the predicted movement range is set, the virtual terminal placement unit 73 (FIG. 6) randomly places a predetermined number of virtual terminals within the predicted movement range, as shown in C of FIG. 10. The number N of virtual terminals to be placed is set, for example, at a density of 10 [units / km2], depending on the area of ​​the predicted movement range. In the example shown in C of FIG. 10, 22 virtual terminals 101, 101-1 to 101-22, are placed.

[0078] The virtual terminal 101 located within the predicted movement range is treated as the transmitting terminal 21 located at a position where the transmitting terminal 21 may be located at time t.

[0079] In step S31 (FIG. 8), the virtual terminal 101 is arranged as described above. In step S32, the reception success counter (Nok) and the virtual terminal counter (Nttl) are initialized. That is, Nok=0 and Nttl=0 are set.

[0080] In step S33, a virtual terminal to be processed is set. As shown in C of Fig. 10, when virtual terminals 101-1 to 101-22 are set, one of these virtual terminals 101 is set as the virtual terminal 101 to be processed.

[0081] In step S34, the received power at the virtual terminal 101 being processed is calculated by the received power calculation unit 74 (FIG. 6). The received power calculation unit 74 calculates the distance between the positions of the satellite receiving station 11 and the virtual terminal 101, and obtains the propagation path loss (PL).

[0082] Furthermore, for the selected beam (beam x selected in step 12), the receiving antenna gain (G_rx) is calculated from the relative positions of the satellite receiving station 11 and the virtual terminal 101. The transmission power of the virtual terminal is set to, for example, 20 mW (P_tx), the transmitting antenna gain is set to, for example, 0 dB (G_tx), and the receiving power is calculated based on equation (2).

[0083]

[0084] Furthermore, the SINR is calculated based on equation (1).

[0085] In equation (1), S is the received power, and the received power calculated in step S34 is used. In equation (1), N is the thermal noise of the satellite receiving station 11, and a measured or set value as the thermal noise is used. In equation (1), I is the amount of interference I, and the value calculated in step 14 (FIG. 7) is used.

[0086] In step S34, when the received power and SINR of the beam x to be processed and the virtual terminal 101 to be received are calculated, the process proceeds to step S35.

[0087] In step S35, it is determined whether the SINR is greater than a threshold (SINR>threshold). The threshold is a value determined depending on the wireless system, and may be, for example, -9.5 Db. In this determination, it is determined whether reception was successful. That is, if the SINR is greater than the threshold, it is determined that reception was successful, and if the SINR is equal to or less than the threshold, it is determined that reception was unsuccessful.

[0088] If it is determined in step S35 that the SINR is greater than the threshold, in other words, if it is determined that reception was successful, the process proceeds to step S36, where the successful reception counter unit 75 (FIG. 6) increments the successful reception counter. The successful reception counter unit 75 also counts the number of virtual terminals that were processed, and in step S37, the processed virtual terminal counter is incremented. If the virtual terminals are managed by numbers assigned to them, the numbers are updated.

[0089] On the other hand, if it is determined in step S35 that the SINR is equal to or less than the threshold, in other words, if it is determined that reception has failed, the process of step S36 is skipped and the process proceeds to step S37. If it is determined that reception has failed, the reception success counter is not updated, and only the virtual terminal counter is updated.

[0090] In step S38, it is determined whether all virtual terminals have been processed. For example, if 22 virtual terminals 101 are set as shown in C of Fig. 10, it is determined whether all 22 virtual terminals 101 have been processed, in other words, whether the virtual terminal counter has reached 22.

[0091] If it is determined in step S38 that there is a virtual terminal 101 that has not yet been processed, the process returns to step S33, and the subsequent steps are repeated. On the other hand, if it is determined in step S38 that all virtual terminals have been processed, the process proceeds to step S39.

[0092] In step S39, the reception success rate is calculated. By repeating the processes of steps S33 to S38, the number of virtual terminals 101 for which reception has been successful among the set virtual terminals 101 is obtained. The number of virtual terminals 101 for which reception has been successful, i.e., the counter value (NoK) of the number of reception successes counted by the reception success number counter unit 75, is divided by the total number of virtual terminals 101 (Nttl) to calculate the reception success rate. Reception success rate = Number of reception successes (NoK) / Total number of virtual terminals (Nttl)

[0093] By performing such processing, the reception success rate for the virtual terminal 101 at time t and beam x is calculated. The reception success rate can be treated as the success rate of the reception process for the transmitting terminal 21.

[0094] Once the reception success rate is calculated, the process returns to step S16 (FIG. 7). In step S16, it is determined whether all beams have been processed. For example, if 52 beams have been processed, it is determined whether all 52 beams have been processed.

[0095] If it is determined in step S16 that not all beams have been processed and that there is still a beam that has not yet been processed, the process returns to step S12, and the subsequent steps are repeated. For example, if beam 0 has been processed, the process returns to step S12, beam 1 is made the new processing target, and the steps from step S13 onward are executed.

[0096] On the other hand, if it is determined in step S16 that all beams have been processed, the process proceeds to step S17, where a beam to be used for demodulation is selected.

[0097] The processing of steps S12 to S16 is repeated to calculate the reception success rate for each beam. For example, if there are 52 beams, all 52 beams are processed, and the reception success rates for all 52 beams are calculated. The calculation results of the reception success rates for all 52 beams are stored in a table such as that shown in FIG. 11.

[0098] 11 is divided into five groups for each direction: directly below, forward, left, backward, and right. For the sake of explanation, the following description will be continued assuming that a table relating to the success rate of reception is created, but the description is not limited to the format of a table, and it is of course possible to create a list of the success rate of reception for each beam using other methods.

[0099] For each group of directions, a beam number, beam information, and reception success rate are associated and recorded. The beam number is a number from 0 to 51 assigned to each beam characteristic in the case described with reference to Fig. 5. The beam information is the number of antenna elements 32 used and the direction in which the beam is pointed.

[0100] In the group for the directly below direction, for example, the beam number is "0", the beam information is "2×1 / (0,0)", and the reception success rate is "50%" are associated and written. In the group for the directly below direction, the reception success rates for beam numbers 0 to 3 are written.

[0101] In the forward direction group, for example, the beam number is "4", the beam information is "2×1 / (0,20)", and the reception success rate is "0%" are associated and recorded. In the forward direction group, the reception success rates of beam numbers 4 to 15 are recorded.

[0102] The group to the left contains, for example, the beam number "16," the beam information "2×1 / (90,20)," and the reception success rate "10%." The group to the bottom left contains the reception success rates for beam numbers 16 to 27.

[0103] In the backward direction group, for example, the beam number is "28", the beam information is "2×1 / (180, 20)", and the reception success rate is "5%" are associated and recorded. In the backward direction group, the reception success rates of beam numbers 28 to 39 are recorded.

[0104] In the right-hand group, for example, the beam number is "40," the beam information is "2×1 / (270, 20)," and the reception success rate is "50%." In the right-hand group, the reception success rates of beam numbers 40 to 51 are listed.

[0105] The created table is referenced to select a beam to be used for demodulation in step S17. A beam that satisfies the following conditions is selected.

[0106] Condition 1: Select one beam from each group with the highest reception success rate. Condition 2: If there are multiple beams with the highest reception success rate within a group, select the one with the fewest number of antennas. Condition 3: If there are multiple beams with the highest reception success rate within a group, select the one closest to the satellite.

[0107] According to condition 1, when there are five groups in five directions as shown in Fig. 11, one beam is selected from each group, so a total of five beams are selected. Note that the number of beams selected from one group may be other than one, for example, two beams may be selected from each group.

[0108] According to condition 2, if there are multiple beams in one group with a reception success rate of, for example, 100%, the beam with the fewest number of antennas is selected. Since fewer antennas reduces digital processing and signal processing costs, if the reception success rate is the same, the beam with the fewest number of antennas is selected.

[0109] According to condition 3, if there are multiple beams in one group with a reception success rate of, for example, 100%, the beam closest to the satellite (directly below the receiving antenna unit 31), in other words, the beam with the smaller value of angle β (B in FIG. 3), is selected. By selecting a beam closer to the satellite, it is possible to select a beam that is closer to the target receiving terminal (transmitting terminal 21). The closer the distance to the target receiving terminal, the higher the reception capability of the desired signal can be expected, and it is possible to have some spare capacity even if, for example, unexpected interference occurs.

[0110] A specific case where the table in FIG. 11 is referenced to select a beam to be used for demodulation will now be described.

[0111] From the group in the directly downward direction, the beam with beam number "2" having a reception success rate of "100%" is selected according to condition 1.

[0112] From the forward direction group, beam number "11" with a reception success rate of "100%" is selected according to condition 1.

[0113] From the group to the left, beams with beam numbers "22" and "25" with a reception success rate of "100%" are selected under condition 1. In this way, when multiple beams are selected under condition 1, one beam is selected under condition 2 or condition 3.

[0114] The beam information for beam number "22" is "3×2 / (90,20)", the number of antennas is 3×2=6, and the value of β is 20. The beam information for beam number "25" is "4×2 / (90,20)", the number of antennas is 4×2=8, and the value of β is 20.

[0115] In this case, due to condition 2, the beam with beam number "22" which has the fewest number of antennas is selected.

[0116] From the backward group, beams with beam numbers "32" and "33" with a reception success rate of "100%" are selected under condition 1. In this way, when multiple beams are selected under condition 1, one beam is selected under condition 2 or condition 3.

[0117] The beam information for beam number "32" is "2×2 / (180, 40)", the number of antennas is 2×2=4, and the value of β is 40. The beam information for beam number "33" is "2×2 / (180, 60)", the number of antennas is 2×2=4, and the value of β is 60.

[0118] In this case, since the number of antennas is the same according to condition 2, a beam is selected according to condition 3. That is, in this case, according to condition 3, the beam with beam number "32" that is closer to the satellite nadir (the beam with smaller β) is selected.

[0119] From the right group, the beam with beam number "42" having a reception success rate of "100%" is selected according to condition 1.

[0120] In this way, beams that meet conditions 1 to 3 are selected.

[0121] Note that the beam selection method described here is an example and is not intended to be limiting. Beams may be selected by other methods. For example, a selection method may be used in which beams are sorted in descending order of reception success rate and the top five beams are selected. A selection method may also be used in which all beams with a reception success rate equal to or greater than a predetermined value are selected.

[0122] When a beam is selected in step S17 (FIG. 7), the process proceeds to step S18. In step S18, demodulation is performed by the demodulation unit 52 (FIG. 6). The demodulation unit 52 reads out data received when the selected beam was used from the storage unit 53, and performs demodulation using the read data. The data received using the beam x selected in step S12 (FIG. 7) is stored in the storage unit 53 in the process of step S13.

[0123] In this way, demodulation processing at time t is performed. The demodulation processing is performed using data received by the selected beam. Even if reception processing is performed using multiple beams, in the above example, 52 beams, the data actually used for demodulation processing is the data received by the selected five beams, so it is possible to reduce the processing required for demodulation, reduce costs, and reduce processing time.

[0124] The demodulation process may be performed at a timing other than immediately after the beam is selected.

[0125] Also, for example, when receiving data from a transmitting terminal 21 that moves slowly or a fixed transmitting terminal 21, after a beam is selected, the receiving process is executed again using the selected beam, for example, five beams, and demodulation is performed using the data received during the receiving process that is executed again.

[0126] A part of the processing performed by the satellite receiving station 11 described above may be configured to be performed by a device other than the satellite receiving station 11. For example, a part of the processing performed by the satellite receiving station 11 may be performed by a server installed on the ground. For example, the received data stored in the storage unit 53 may be supplied to a server installed on the ground, and demodulation processing may be performed on the server side.

[0127] In addition, the satellite receiving station 11 may be configured to perform processing related to reception, and all data obtained by reception may be supplied to the server side, where processing such as calculation of the interference amount I, calculation of the reception success rate, beam selection, and demodulation processing may be performed.

[0128] As described above, according to the present technology, when receiving using digital beamforming, it is possible to select an optimal beam. As described above, the present technology can improve reception with the transmitting terminal 21 through processing on the satellite receiving station 11 side, and therefore can also be applied to wireless systems for one-way communication.

[0129] According to this technology, by calculating the reception success rate using a virtual terminal and performing processing using the reception success rate as an index, it is possible to apply it to a mobile terminal where the transmitting terminal 21 moves. In addition, since the index takes into account the amount of interference, it is possible to suppress the deterioration of reception due to interference and improve reception accuracy.

[0130] <Regarding the Recording Medium> The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, the programs that make up the software are installed on a computer. Here, the term "computer" includes computers built into dedicated hardware, and general-purpose personal computers, for example, that can execute various functions by installing various programs.

[0131] 12 is a block diagram showing an example of the hardware configuration of a computer that executes the above-mentioned series of processes using a program. In the computer, a CPU (Central Processing Unit) 2001, a ROM (Read Only Memory) 2002, and a RAM (Random Access Memory) 2003 are interconnected by a bus 2004. An input / output interface 2005 is also connected to the bus 2004. An input unit 2006, an output unit 2007, a storage unit 2008, a communication unit 2009, and a drive 2010 are connected to the input / output interface 2005.

[0132] The input unit 2006 includes a keyboard, a mouse, a microphone, etc. The output unit 2007 includes a display, a speaker, etc. The storage unit 2008 includes a hard disk, a non-volatile memory, etc. The communication unit 2009 includes a network interface, etc. The drive 2010 drives removable media 2011 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

[0133] In a computer configured as described above, the CPU 2001 performs the above-described series of processes by, for example, loading a program stored in the memory unit 2008 into the RAM 2003 via the input / output interface 2005 and the bus 2004 and executing it.

[0134] The program executed by the computer (CPU 2001) can be provided by being recorded on, for example, a removable medium 2011 such as a package medium. The program can also be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

[0135] In the computer, the program can be installed in the storage unit 2008 via the input / output interface 2005 by inserting the removable medium 2011 into the drive 2010. The program can also be received by the communication unit 2009 via a wired or wireless transmission medium and installed in the storage unit 2008. Alternatively, the program can be installed in advance in the ROM 2002 or the storage unit 2008.

[0136] The program executed by the computer may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0137] In this specification, a system refers to an entire device made up of multiple devices.

[0138] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0139] It should be noted that the embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible within the scope of the present technology.

[0140] The present technology can also be configured as follows: (1) A data processing device comprising: a reception signal generation unit that generates a reception signal for each beam generated by digital beamforming; an interference amount calculation unit that calculates an amount of interference interfering with a desired reception wave using the reception signal generated by the reception signal generation unit; a reception success rate calculation unit that calculates a reception success rate at which signals from a target reception terminal are successfully received; a beam selection unit that selects a beam with a high reception success rate calculated by the reception success rate calculation unit; and a demodulation unit that performs demodulation using data received by the beam selected by the beam selection unit. (2) The data processing device according to (1), wherein the reception success rate calculation unit sets a range in which a transmitting terminal that transmits the desired reception wave may be located, arranges multiple virtual terminals within the range, calculates a signal to noise ratio (SINR) for each virtual terminal using the amount of interference calculated by the interference amount calculation unit, and calculates the reception success rate by dividing the number of virtual terminals whose SINR is equal to or greater than a predetermined value by the total number of the multiple virtual terminals. (3) The data processing device according to (2), wherein the range is a circle whose radius is a value obtained by multiplying the moving speed of the transmitting terminal by the elapsed time since the time the position of the transmitting terminal was last updated, and whose center is the last updated position of the transmitting terminal. (4) The data processing device according to (2) or (3), wherein the beam selection unit groups the reception success rates for each direction of the beam, and selects a predetermined number of the beams from each group. (5) The data processing device according to (4), wherein if there are multiple beams with the same reception success rate in the same group, a beam using fewer antennas to form the beam is selected. (6) The data processing device according to (4) or (5), wherein if there are multiple beams with the same reception success rate in the same group, a beam closest to being directly below an antenna is selected. (7) The data processing device according to any of (1) to (6), further comprising a storage unit that stores data received for each beam, and wherein the demodulation unit reads out the data received using the beam selected by the beam selection unit from the storage unit and performs demodulation processing.(8) The data processing device according to any one of (1) to (7) above, which is mounted on a satellite. (9) A data processing method, in which a data processing device generates a reception signal for each beam generated by digital beamforming, calculates an amount of interference interfering with a desired reception wave using the generated reception signal, calculates a reception success rate at which signals from a target reception terminal are successfully received, selects a beam with a high calculated reception success rate, and demodulates data received by the selected beam.

[0141] REFERENCE SIGNS LIST 1 Data processing system, 11 Satellite receiving station, 21 Transmitting terminal, 23 Interference source, 31 Receiving antenna unit, 32 Antenna element, 33 Multiplication unit, 34 Addition unit, 40 Received signal generation unit, 51 Interference amount calculation unit, 52 Demodulation unit, 53 Storage unit, 60 Reception success rate calculation processing unit, 71 Terminal position setting unit, 72 Radius setting unit, 73 Virtual terminal placement unit, 74 Reception power calculation unit, 75 Reception success number counter unit, 76 Reception success rate calculation unit, 90 On / Off unit, 101 Virtual terminal

Claims

1. A data processing device comprising: a reception signal generation unit that generates a reception signal for each beam generated by digital beamforming; an interference amount calculation unit that calculates the amount of interference interfering with a desired reception wave using the reception signal generated by the reception signal generation unit; a reception success rate calculation unit that calculates a reception success rate at which a signal is successfully received from a target terminal; a beam selection unit that selects a beam with a high reception success rate calculated by the reception success rate calculation unit; and a demodulation unit that performs demodulation using data received by the beam selected by the beam selection unit.

2. The data processing device of claim 1, wherein the reception success rate calculation unit sets a range in which a transmitting terminal transmitting the desired reception wave may be located, places a plurality of virtual terminals within the range, calculates a SINR (Signal to Noise Ratio) for each virtual terminal using the amount of interference calculated by the interference amount calculation unit, and calculates the reception success rate by dividing the number of virtual terminals whose SINR is equal to or greater than a predetermined value by the total number of the plurality of virtual terminals.

3. The data processing device according to claim 2, wherein the range is a circle whose radius is the product of the moving speed of the transmitting terminal and the elapsed time since the time the position of the transmitting terminal was last updated, and whose center is the last updated position of the transmitting terminal.

4. The data processing device according to claim 2, wherein the beam selection unit groups the reception success rates for each beam direction and selects a predetermined number of the beams from each group.

5. A data processing device according to claim 4, wherein when there are a plurality of beams with the same success rate of reception in the same group, a beam using a fewer number of antennas to form the beam is selected.

6. The data processing device according to claim 4, wherein when there are a plurality of beams with the same reception success rate in the same group, the beam closest to directly below the antenna is selected.

7. A data processing device as described in claim 1, further comprising a memory unit for storing received data for each beam, wherein the demodulation unit reads out the data received using the beam selected by the beam selection unit from the memory unit and performs demodulation processing.

8. The data processing device according to claim 1, which is installed on a satellite.

9. A data processing method in which a data processing device generates a reception signal for each beam generated by digital beamforming, calculates the amount of interference interfering with a desired reception wave using the generated reception signal, calculates a reception success rate at which signals from a target receiving terminal are successfully received, selects a beam with a high calculated reception success rate, and demodulates data received by the selected beam.

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