Method for generating database for full-duplex communication and method for full-duplex wireless communication

Abstract

To provide a full duplex communication method capable of stably cancelling a sneak signal with respect to fluctuation or difference.SOLUTION: A database generation method for full duplex communications for generating a database for cancelling a sneak signal transmitted by a transmit antenna and further received by a receive antenna using a communication apparatus which performs wireless communications using full duplex wireless communications includes: a sneak reception step of receiving only a sneak signal for reference; and a generation step of sampling the received sneak signal for reference and further generating a database for recording the sneak signal for reference. In the generation step, the database is successively generated in such a manner that the quantities of information become different respectively in accordance with any one or more of period information relating to a length of a period in which the sneak signal for reference is received by the receive antenna and cycle information relating to a cycle in which the sneak signal for reference is sampled.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for generating a database for full-duplex communication and a full-duplex wireless communication method for wirelessly communicating by full-duplex wireless communication. [Background technology]

[0002] In the conventional frequency band below 6 GHz, the average throughput has increased by approximately 1.5 times per year due to the increase in mobile phone lines, and the problem of frequency shortage has become a regular occurrence. In addition, with the introduction of the 5th generation mobile communication system (5G), the use of high SHF (Super High Frequency) bands etc. will also begin, but it is not necessarily possible to secure a large number of channels, and it is thought that the problem of frequency shortage cannot be resolved.

[0003] For this reason, in the next generation communication standard after 5G, B5G (Beyond 5G), it is necessary to deal with the further rapid increase in mobile traffic caused by the increase in mobile phone lines. In particular, in recent years, various technologies have been developed with the aim of improving the effective utilization efficiency of such frequencies. One of these technologies is full-duplex wireless communication technology, which is a type of wireless multiplexing technology that simultaneously transmits and receives wireless signals.

[0004] Full-duplex wireless communication technology transmits and receives wireless signals simultaneously, and in principle can double the frequency utilization efficiency. For this reason, it is highly useful in 5G and B5G wireless communication systems, including IoT systems.

[0005] In the technology disclosed in Non-Patent Document 1, full-duplex wireless communication is performed between a plurality of wireless terminals and a base station, and therefore effective use of frequency resources is achieved in order to expand radio wave resources. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Bharadia, E. McMilin, and S. Katti, “Full duplex radios.” In Proceedings of the ACM SIGCOMM 2013 conference on SIGCOMM'13, pages 375-386, NewYork, NY, USA, 2013. Summary of the Invention [Problem to be solved by the invention]

[0007] However, this full-duplex wireless communication technology transmits and receives wireless signals simultaneously and at the same frequency, so that the transmission signal sent by the device itself is mixed with the received signal due to a loop signal that gets into the receiving circuit, which causes degradation of communication quality due to so-called self-interference. For this reason, in wireless communication systems that implement full-duplex wireless communication technology, it is essential to implement a self-interference cancellation technology to fully cancel this self-interference.

[0008] Generally, self-interference cancellation is realized by optimal design and development according to frequency, targeting antenna isolation, high-frequency analog canceller, and baseband digital canceller, as shown in Fig. 6. It is relatively easy to achieve an isolation of several tens of dB for antenna isolation 9 by adjusting the distance and arrangement of transmitting antenna 71 and receiving antenna 72. Also, baseband digital canceller 73 is an interference canceller in the digital domain, and although it is system-dependent, it is not frequency-dependent, and the input signal level is converged to a certain range by the analog circuit in the previous stage, so the same interference canceller can be applied to systems of different frequencies.

[0009] The high-frequency analog canceller 74 implements a feedback circuit between the transmitting circuit 75 and the receiving circuit 76, and uses its own transmitting signal as a reference signal to perform optimal gain (signal level) and delay correction so that the feedback signal from the transmitting antenna 71 has the same amplitude and opposite phase as the feedback signal, and cancels the feedback signal by mixing the reference signal with the feedback signal.

[0010] Incidentally, in such a self-interference canceller in a high-frequency analog circuit, the target interference signal changes depending on, for example, the distance and arrangement of the transmitting antenna 71 and the receiving antenna 72. For this reason, it is necessary to create a database 77 in which reference interference signals that are transmitted from the transmitting antenna 71 to the receiving antenna 72 are recorded in advance, and to refer to the reference interference signals recorded in the database 77 to perform optimal gain and delay corrections and generate a reference signal.

[0011] In such a case, the amount of information required for database 77 to stably cancel the looping signal changes due to temporal fluctuations in the communication environment or differences in the communication environment between terminals. For example, the optimal amount of information required differs between a daytime communication environment where the communication volume is high and a nighttime communication environment where the communication volume is low. If the amount of information is less than the optimal amount required, the accuracy of communication becomes unstable, and if the amount of information is more than the optimal amount required, extra communication costs are incurred. For this reason, in order to stably cancel the looping signal, it is necessary to apply database 77 with an amount of information suited to the communication environment.

[0012] In addition, for example, a typical transmitting antenna 71 and a receiving antenna 72 have directivity that changes the accuracy of communication depending on the direction of the communication device performing wireless communication. Therefore, the amount of information required to stably cancel the loop interference signal varies according to the above-mentioned direction. Therefore, in order to stably cancel the loop interference signal, it is necessary to apply a database 77 with an amount of information that matches the directivity of the antenna.

[0013] However, in the technology disclosed in Non-Patent Document 1, the same database 77 is operated even when the communication environment fluctuates over time, differs between terminals, or the direction from the communication device changes, so that it is not possible to stably cancel the echo signal in the face of such fluctuations and differences.

[0014] The present invention has been developed to solve the above-mentioned problems, and aims to provide a database generation method for full-duplex communication and a full-duplex wireless communication method that are capable of stably canceling loop interference signals despite temporal fluctuations and differences in the communication environment. [Means for solving the problem]

[0015] A database generating method for full-duplex communication according to a first aspect of the present invention is a database generating method for full-duplex communication using a communication device having a transmitting antenna for transmitting a transmitting signal and a receiving antenna for receiving a receiving signal, and which wirelessly communicates with an external terminal using full-duplex wireless communication, for generating a database for canceling a loop interference signal received by the receiving antenna from a transmitting signal transmitted by the transmitting antenna, the database comprising: The reference transmission signal transmitted by the transmitting antenna is received by the receiving antenna. The method includes a loop receiving step of receiving only a reference loop signal, and a generation step of sampling the reference loop signal received by the loop receiving step and generating the database in which the reference loop signal is recorded, and the generation step is characterized in that the database is sequentially generated so that the amount of information varies depending on at least one of period information regarding the length of the period during which the reference loop signal is received by the receiving antenna and period information regarding the period for sampling the reference loop signal.

[0016] A database generating method for full-duplex communication according to a second invention is characterized in that, in the first invention, the loop reception step acquires directional information regarding the direction of the transmitting antenna or the receiving antenna in a direction from the external terminal to the communication device, and the generation step performs a process of determining one or more of the period information and the period information according to the directional information acquired by the loop reception step.

[0017] The database generation method for full-duplex communication according to the third invention is characterized in that, in the second invention, when the directional information acquired in the wraparound reception step is identical to other directional information, the generation step generates a database with the same amount of information as the database generated for the other directional information.

[0018] A full-duplex wireless communication method according to a fourth invention is characterized in that, in the second invention, the generating step shares the database generated for another directional information when the directional information acquired in the wraparound receiving step is identical to the other directional information.

[0019] A full-duplex wireless communication method according to a fifth aspect of the present invention is a full-duplex wireless communication method for performing full-duplex wireless communication between a communication device having a transmitting antenna for transmitting a transmission signal and a receiving antenna for receiving a reception signal, and an external terminal, the full-duplex wireless communication method comprising: For referenceThe method includes a loop receiving step of receiving only a reference loop signal received by the receiving antenna from a transmitted signal, a generation step of sampling the reference loop signal received by the loop receiving step and sequentially generating a database for recording the reference loop signal, a communication receiving step of receiving a new received signal including a loop signal by the receiving antenna, and a processing step of referring to one or more of the databases generated by the generation step and canceling the loop signal included in the received signal received by the communication receiving step, wherein the generation step is characterized in that the databases are sequentially generated so that the amount of information varies depending on one or more of period information regarding the length of the period during which the reference loop signal is received by the receiving antenna and period information regarding the period for sampling the reference loop signal.

[0020] A full-duplex wireless communication method according to a sixth aspect of the present invention is characterized in that, in the fifth aspect of the present invention, the generating step generates a database for each of the external terminals, the communication receiving step acquires, for each of the external terminals, directional information relating to the directional orientation of the transmitting antenna or the receiving antenna relative to a direction toward the communication device, and the processing step, when the directional information of the external terminal newly acquired in the communication receiving step is identical to directional information of another external terminal, refers to the database generated for the other external terminal. Effect of the Invention

[0021] According to the first to sixth aspects of the invention, databases are sequentially generated so that the amount of information varies depending on at least one of period information on the length of the period during which the reference interference signal is received by the receiving antenna and period information on the period at which the reference interference signal is sampled. This makes it possible to generate multiple databases with different amounts of information depending on the period information or period information, and therefore makes it possible to refer to databases with appropriate amounts of information for fluctuations and differences in the communication environment. This makes it possible to stably cancel the interference signal despite fluctuations and differences in the communication environment.

[0022] In particular, according to the second invention, the generation step determines one or more of the period information and the cycle information according to the direction information acquired by the wraparound reception step. As a result, since the amount of information in the appropriate database can be determined according to the direction information, it is possible to cancel the wraparound signal stably against fluctuations and differences due to changes in directivity.

[0023] In particular, according to the third invention, when the direction information acquired in the wraparound reception step is the same as other direction information, the generation step generates a database having the same amount of information as the database generated for the other direction information. As a result, for example, when the direction information is the same, the amount of information in the database can be determined uniquely, so the burden of generating the database is reduced.

[0024] In particular, according to the fourth invention, when the direction information acquired in the wraparound reception step is the same as other direction information, the generation step is characterized by sharing the database generated for the other direction information. As a result, since the same database can be shared among external terminals with the same direction information, the burden of generating the database is reduced.

[0025] In particular, according to the sixth invention, when the direction information of the external terminal newly acquired in the communication reception step is the same as the direction information of other external terminals, the processing step refers to the database generated for the other external terminals. As a result, when performing wireless communication with a plurality of external terminals, for example, if the direction information is the same, the same database can be shared among the external terminals, so the burden of canceling the wraparound signal is reduced.

Brief Description of the Drawings

[0026] [Figure 1] FIG. 1 is an overall schematic diagram of a wireless communication system to which a database generation apparatus and a self-interference cancellation circuit to which the present invention is applied are applied. [Diagram 2] FIG. 2 shows a block configuration of the self-interference cancellation circuit. [Diagram 3] FIG. 3 shows a block configuration of the database generating device. [Figure 4] FIG. 4 shows a flow chart of a full-duplex wireless communication method to which the present invention is applied. [Diagram 5] FIG. 5 shows the directivity of the antenna. [Figure 6] FIG. 6 is a diagram for explaining a general self-interference cancellation method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, a self-interference cancellation circuit to which the present invention is applied will be described in detail with reference to the drawings.

[0028] 1 is an overall schematic diagram of a wireless communication system 1 to which the present invention is applied. The wireless communication system 1 includes a base station 2 and a plurality of user terminals 3. The wireless communication system 1 will be described taking as an example a case where a full-duplex wireless communication method, which is a duplex method that uses the same frequency and the same time slot and performs transmission and reception simultaneously, as an example, but is not limited to this and may also be a system that employs a general half-duplex wireless communication method.

[0029] The base station 2 serves as a wireless access point between the user terminal 3 and the base station 2, and serves as an interface between the base station 2 and a public communication network such as the Internet. That is, the base station 2 serves as a relay means that enables the user terminal 3 to transmit and receive data between the base station 2 and a public communication network such as the Internet. The base station 2 performs wireless communication with the user terminal 3 based on the above-mentioned full-duplex wireless communication method. The base station 2 also includes a self-interference cancellation circuit 10 for canceling a loopback signal.

[0030] The user terminal 3 is configured with a terminal device capable of wireless communication, such as a notebook personal computer (PC), a mobile terminal, a smartphone, a tablet terminal, a wearable terminal, etc. Such a user terminal 3 transmits and receives packet data between the base station 2 via wireless communication, using a transmission signal or a reception signal having a radio frequency.

[0031] FIG. 2 shows a block configuration of the self-interference cancellation circuit 10. The self-interference cancellation circuit 10 is roughly classified into a database generating device 4, a receiving circuit 5 and a transmitting circuit 6 connected to the database generating device 4, and a local oscillator circuit 8 connected to the receiving circuit 5 and the transmitting circuit 6. The self-interference cancellation circuit 10 applies a so-called superheterodyne circuit configuration, and the receiving circuit 5 band-converts the radio frequency of the received signal received from the user terminal 3 to generate a converted signal, which is then output to the inside of the base station 2. The transmitting circuit 6 band-converts the converted signal output from the inside of the base station 2 to a radio frequency, converts the converted signal into a transmission signal, and transmits it to the user terminal 3. The local oscillator circuit 8 supplies the reference signal to be mixed in each band conversion to the receiving circuit 5 and the transmitting circuit 6, respectively. Each of these configurations will be described in detail below.

[0032] The receiving circuit 5 comprises a receiving antenna 11, a processor 31 connected to the receiving antenna 11 and the database generation device 4, a coupler 32 connected to the receiving antenna 11 and the processor 31, an amplifier 12 connected to the coupler 32, a receiving band filter 13 connected to the amplifier 12, an attenuator 14 connected to the receiving band filter 13, a mixer 15 connected to the attenuator 14, a filter 16 connected to the mixer 15, a high gain amplifier 18 connected to the filter 16, and an attenuator 19 connected to the high gain amplifier 18, and the attenuator 19 is connected inside the base station 2.

[0033] The transmission circuit 6 includes an attenuator 21 connected inside the base station 2, a mixer 22 connected to the attenuator 21, a bandpass filter 23 connected to the mixer 22, a buffer amplifier 24 connected to the bandpass filter 23, a variable attenuation circuit 25 connected to the buffer amplifier 24, a driver amplifier 26 connected to the variable attenuation circuit 25, a power amplifier 28 connected to the driver amplifier 26, an isolator 29 connected to the power amplifier 28, and a database generation device 4 and a transmission antenna 30 connected to the isolator 29.

[0034] The local oscillator circuit 8 comprises a reference clock 41 and voltage-controlled oscillators 42 and 43 connected to the reference clock 41. The voltage-controlled oscillator 42 is connected to the mixer 15 in the receiving circuit 5, and the voltage-controlled oscillator 43 is connected to the mixer 22 in the transmitting circuit 6.

[0035] The receiving antenna 11 is an antenna for receiving a reception signal consisting of a higher radio frequency transmitted from the user terminal 3. The components of the reception signal received by this receiving antenna 11 include components that may be so-called self-interference due to a feedback signal received by the transmission signal transmitted from the transmitting antenna 30. The receiving antenna 11 converts the radio signal of the reception signal including such feedback signals into an electrical signal, and outputs it to the coupler 32, the database generating device 4, and the processor 31.

[0036] The processor 31 refers to a database 55 (described later) recorded by the database generator 4, and outputs to the coupler 32 a reference signal that has been subjected to optimal gain and delay correction so that the feedback signal contained in the received signal has the same amplitude but the opposite phase to the feedback signal.

[0037] The coupler 32 receives an electrical signal of the received signal including a feedback signal from the receiving antenna 11. The coupler 32 also receives a reference signal from the processor 31. The coupler 32 performs a process of mixing the electrical signal and the reference signal. This allows the feedback signal contained in the electrical signal to be superimposed on the reference signal, which has been subjected to optimal gain and delay compensation so that the feedback signal has the same amplitude and opposite phase as the feedback signal, thereby canceling the feedback signal itself. The coupler 32 outputs the electrical signal from which the feedback signal has been cancelled to the amplifier 12.

[0038] The amplifier 12 amplifies the electrical signal output from the coupler 32 and outputs it to the receive band filter 13 .

[0039] The receiving band filter 13 limits the band of the electrical signal from the amplifier 12 to a predetermined range, and then outputs it to the attenuator 14 .

[0040] The attenuator 14 attenuates the electrical signal input from the receiving band-pass filter 13 and outputs the attenuated electrical signal to the mixer 15 .

[0041] The mixer 15 mixes the reference signal output from the local oscillator circuit 8 with the electrical signal to generate a converted signal. The mixer 15 outputs the converted signal to the filter 16.

[0042] Filter 16 extracts specific frequency components from the converted signal input from mixer 15 and applies band limitation to other frequency components. Band limitation is performed in reception band filter 13, but this is performed in a high-frequency radio frequency band, so by applying band limitation again in this specific frequency range, unnecessary frequency components are cut. Filter 16 outputs the band-limited converted signal to high-gain amplifier 18.

[0043] The high gain amplifier 18 is a circuit that performs high gain amplification on the converted signal input from the filter 16. The high gain amplifier 18 outputs the amplified converted signal to the attenuator 19.

[0044] The attenuator 19 attenuates the converted signal input from the high gain amplifier 18, and then transmits it to the inside of the base station 2, where various information contained therein is utilized.

[0045] The attenuator 21 attenuates the converted signal input from inside the base station 2 and outputs the attenuated signal to the mixer 22 .

[0046] The mixer 22 mixes the reference signal output from the local oscillator circuit 8 with the converted signal to generate an electrical signal of the transmission signal converted to a high radio frequency. The mixer 22 outputs the transmission signal converted to a radio frequency component to the bandpass filter 23.

[0047] The bandpass filter 23 performs filtering on the transmission signal output from the mixer 22 so that only a predetermined band passes and restricts other bands, and outputs the result to a buffer amplifier 24 .

[0048] The buffer amplifier 24 amplifies the transmission signal output from the bandpass filter 23 and outputs it to a variable attenuation circuit 25 .

[0049] The variable attenuation circuit 25 adjusts the amount of attenuation for the transmission signal input from the buffer amplifier 24 so that the output level is appropriate, and outputs this to the driver amplifier 26 .

[0050] The driver amplifier 26 amplifies the transmit signal to a desired voltage level and outputs it to a power amplifier 28 .

[0051] The power amplifier 28 amplifies the power of the transmission signal supplied from the driver amplifier 26 and outputs the amplified signal to the isolator 29 .

[0052] The isolator 29 is a device for isolating a circuit that generates a transmission signal as necessary and leads it to the transmission antenna 30. When the transmission signal from the power amplifier 28 passes through the isolator 29, it is output to the transmission antenna 30.

[0053] The reference clock 41 is a clock to be referred to when actually generating a reference signal. The voltage-controlled oscillator 42 refers to time information from the reference clock 41 when oscillating the reference signal to be supplied to the mixer 15. Similarly, the voltage-controlled oscillator 43 refers to time information from the reference clock 41 when oscillating the reference signal to be supplied to the mixer 22.

[0054] Next, a configuration of the database generating device 4 for generating the database 55 for canceling the loop interference signal will be described. The database 55 for canceling the loop interference signal is a database in which sampled reference loop interference signals are recorded and which is used to create reference signals necessary for canceling the loop interference signal.

[0055] 3 is a diagram showing a block configuration of the database generating device 4. The database generating device 4 includes a reception information acquiring unit 50 connected to the transmitting antenna 30, a directivity information acquiring unit 51, a period information determining unit 52 connected to the reception information acquiring unit 50 and the directivity information acquiring unit 51, a period information determining unit 53 connected to the directivity information acquiring unit 51, a database generating unit 54 connected to the receiving antenna 11, the period information determining unit 52, and the period information determining unit 53, and a recording unit 56 connected to the database generating unit 54. The recording unit 56 is also connected to the processor 31.

[0056] The reception information acquisition unit 50 acquires reception information relating to the reception status of the receiving antenna 11, and outputs a reference transmission signal to the transmitting antenna 30 according to the reception information. The reception information acquisition unit 50 may also output the acquired reception information to the period information determination unit 52.

[0057] The direction information acquisition unit 51 acquires direction information regarding the direction of the transmission antenna 30 or the reception antenna 11 with respect to the direction from the user terminal 3 to the base station 2. The direction information acquisition unit 51 outputs the acquired direction information to the period information determination unit 52 and the cycle information determination unit 53.

[0058] The period information determination unit 52 acquires period information regarding the length of the period during which the reception antenna 11 receives the reference wrap-around signal according to the reception information output from the reception information acquisition unit 50 or the direction information output from the direction information acquisition unit 51. The period information determination unit 52 outputs the acquired period information to the database generation unit 54.

[0059] The cycle information determination unit 53 acquires cycle information regarding the cycle for sampling the reference wrap-around signal according to the direction information output from the direction information acquisition unit 51. The cycle information determination unit 53 outputs the acquired cycle information to the database generation unit 54.

[0060] The database generation unit 54 receives the reference wrap-around signal by the reception antenna 11 according to the period information output from the period information determination unit 52. The database generation unit 54 samples the received reference wrap-around signal according to the cycle information output by the cycle information determination unit 53. The database generation unit 54 creates a plurality of databases 55 that record the sampled reference wrap-around signals with different amounts of information according to one or more of the period information and the cycle information. The database generation unit 54 outputs the generated databases 55 to the recording unit 56.

[0061] The recording unit 56 stores the generated databases 55 and outputs the databases 55 to the processing unit 31 as necessary.

[0062] Next, the operation of canceling a loop signal in full-duplex wireless communication according to this embodiment will be described with reference to Fig. 4. The operation of canceling a loop signal in this embodiment generates a database 55 for canceling the loop signal through a loop reception step S11 for receiving a reference loop signal and a generation step S12 for generating a database 55. Thereafter, the operation of canceling the loop signal is completed by referring to the database 55 through a communication reception step S13 for receiving a new received signal and a processing step S14 for canceling the loop signal. Each step will be described in detail below.

[0063] First, in a wraparound reception step S11, the directivity information acquisition unit 51 acquires directivity information relating to the directivity of the transmitting antenna 30 or the receiving antenna 11 in the direction from the user terminal 3 to the base station 2. The directivity information acquisition unit 51 acquires the directivity information based on GPS position information of the user terminal 3, or the relative positional relationship between the base station 2 and the user terminal 3, etc. In this case, the user terminal 3 may not actually be communicating, but may be a user terminal 3 that is assumed to communicate wirelessly using the generated database 55, for example. The directivity information acquisition unit 51 outputs the acquired directivity information to the period information determination unit 52 and the period information determination unit 53.

[0064] The directional information may be, for example, as shown in FIG. 5, information indicating the angle of the direction B from the user terminal 3 to the base station 2 with respect to the direction A in which the receiving antenna 11 is oriented, the position of the user terminal 3 with respect to the direction A in which the receiving antenna 11 is oriented, or the degree of energy loss of a transmission signal or a reception signal in wireless communication between the receiving antenna 11 oriented in the direction A and the user terminal 3 located in the direction B from the base station 2. The accuracy of communication of a directional antenna such as the receiving antenna 11 changes depending on the change in the direction B from the user terminal 3 to the base station 2 with respect to the direction A in which the antenna is oriented. For example, the energy loss of the reception signal received by the receiving antenna 11 when communicating with the user terminal 3b located in the direction B2, which has an angle larger than the angle of the direction B1 with respect to the direction A, becomes larger than when communicating with the user terminal 3a located in the direction B1 using the receiving antenna 11 oriented in the direction A. For this reason, the amount of information required in the database 55 differs depending on the directional information between the receiving antenna 11 or the transmitting antenna 30 and the user terminal 3.

[0065] Next, the reception information acquisition unit 50 acquires reception information regarding the reception status of the reception signal by the receiving antenna 11. The reception information may be, for example, information indicating whether the receiving antenna 11 is receiving a reception signal, information indicating the degree of reception of the reception signal by the receiving antenna 11, or information indicating the source of the reception signal received by the receiving antenna 11. The reception information acquisition unit 50 controls the transmission of the reference transmission signal by the transmitting antenna 30 according to the reception information. For example, when the receiving antenna 11 is not receiving a reception signal, the reception information acquisition unit 50 preferably transmits the reference transmission signal to the transmitting antenna 30 and receives the reference loop signal by the receiving antenna 11 according to the reception information, but this is not limited thereto. For example, when the degree of reception of the reception signal by the receiving antenna 11 is lower than a preset threshold, the reception information acquisition unit 50 may transmit the reference transmission signal to the transmitting antenna 30 and receive the reference loop signal by the receiving antenna 11. Furthermore, when the source of the received signal received by the receiving antenna 11 is only the transmitting antenna 30, the reception information acquisition unit 50 may transmit a reference transmission signal to the transmitting antenna 30 and receive the reference loop signal by the receiving antenna 11. Furthermore, the reception information acquisition unit 50 may output the reception information to the period information determination unit 52.

[0066] The reference transmission signal is a transmission signal transmitted from the transmitting antenna 30 in order to generate the database 55. The reference interference signal is a interference signal received by the receiving antenna 11 from the reference transmission signal transmitted from the transmitting antenna 30 in order to generate the database 55.

[0067] Next, in the generation step S12, the period information determination unit 52 determines and acquires period information regarding the length of the period during which the reference loop signal is received by the receiving antenna 11, according to the reception information output from the reception information acquisition unit 50 or the directivity information output from the directivity information acquisition unit 51. The period information may be, for example, the date and time at which reception of the reception signal by the receiving antenna 11 starts and the date and time at which reception ends, or the length of the period from the date and time at which reception starts to the date and time at which reception ends. When the reception information is input by the reception information acquisition unit 50, the period information determination unit 52 determines and acquires the period information so that, for example, the receiving antenna 11 receives only the reference transmission signal transmitted from the transmitting antenna 30. Furthermore, when the directivity information is input by the directivity information acquisition unit 51, the period information determination unit 52 may determine and acquire the period information according to the directivity information. In this case, for example, when the input directivity information is information indicating the degree of energy loss of the received signal in wireless communication, the period information determination unit 52 may determine the length of the period from the date and time at which reception starts to the date and time at which reception ends, according to the degree of energy loss. This makes it possible to generate a database 55 with an appropriate amount of information according to the directivity information between the receiving antenna 11 or the transmitting antenna 30 and the user terminal 3.

[0068] Furthermore, the period information determination unit 52 may acquire the period information without receiving the reception information and the directional information. In such a case, for example, the period information determination unit 52 may determine the period information so that the reference loop signal is received for a long time during the daytime when the communication volume is high, and may determine the period information so that the reference loop signal is received for a short time during the nighttime when the communication volume is low. This makes it possible to generate the database 55 with an appropriate amount of information for each variation and difference in the communication environment.

[0069] Moreover, the period information determination unit 53 determines and acquires period information related to the period for sampling the reference wraparound signal. The period information is information related to the period for sampling the reference wraparound signal, and may be, for example, information indicating that sampling is performed once every 10 seconds, but is not limited thereto. The period information determination unit 53 may determine period information so that the sampling period is short during the daytime when the communication volume is high, and may determine period information so that the sampling period is long during the nighttime when the communication volume is low. In generating the database 55, the shorter the sampling period and the higher the sampling frequency, the larger the amount of information in the database 55. Therefore, it is possible to generate the database 55 with an appropriate amount of information for each fluctuation and difference in the communication environment.

[0070] Furthermore, the period information determination unit 53 may determine and acquire period information according to the directivity information output from the directivity information acquisition unit 51. In this case, for example, when the input directivity information is information indicating the degree of energy loss of a received signal in wireless communication, the period information determination unit 53 may determine the period of the reference feedback signal according to the degree of energy loss. This makes it possible to generate a database 55 with an appropriate amount of information according to the directivity information between the receiving antenna 11 or transmitting antenna 30 and the user terminal 3.

[0071] Next, the database generating unit 54 controls the reception of the reference wraparound signal by the receiving antenna 11 based on the period information output from the period information determining unit 52. In this case, the database generating unit 54 may control the reception of the reference wraparound signal only during the period indicated by the period information. Also, the database generating unit 54 may acquire only the reference wraparound signal received during the period indicated by the period information among the reference wraparound signals received by the receiving antenna 11. After that, the database generating unit 54 samples the received or acquired reference wraparound signal based on the period information, and then sequentially generates databases 55 for recording the sampled reference wraparound signals. The database generating unit 54 sequentially generates databases 55 such that the amount of information differs depending on the period information or period information. The database generating unit 54 may sequentially generate databases 55 with different amounts of information for each period information or period information from reference wraparound signals indicating the same information. Also, the database generating unit 54 may generate databases 55 with different amounts of information for each type of reference wraparound signal, such as a reference wraparound signal indicating an image or a reference wraparound signal indicating a sound. This makes it possible to generate multiple databases 55 with different amounts of information according to the period information or cycle information, and therefore to refer to the appropriate database 55 in response to fluctuations and differences in the communication environment. This makes it possible to stably cancel loop interference signals even when the communication environment fluctuates or differs.

[0072] Furthermore, in the generating step S12, when the acquired directional information is the same as other directional information in the wraparound receiving step S11, the database 55 may be generated with the same amount of information as the database 55 corresponding to the other directional information. This allows the amount of information of the database 55 to be uniquely determined, for example, when the directional information is the same, so that the burden of generating the database 55 is reduced. In addition, in the generating step S12, when the acquired directional information is the same as other directional information, the database 55 generated for the other directional information may be shared. This allows the same database 55 to be shared between external terminals having the same directional information, so that the burden of generating the database 55 is reduced. In addition, the database 55 may be generated so as to correspond to each user terminal 3 with which communication is expected. In addition, the database 55 may be created in advance before starting new communication, or may be generated immediately before communication is performed.

[0073] Next, the operation of the self-interference cancellation circuit 10 for canceling the sneak interference signal with reference to the database 55 will be described.

[0074] In the self-interference cancellation circuit 10, a converted signal is first produced under a full-duplex wireless communication system, which is a duplex system in which transmission and reception are performed simultaneously. The converted signal is generated inside the base station 2 and is supplied to an attenuator 21.

[0075] The converted signal supplied to the attenuator 21 is attenuated and then output to the mixer 22. The converted signal output to the mixer 22 is mixed with a reference signal supplied from a local oscillator circuit 8 to become a transmission signal converted to a high radio frequency. The transmission signal is band-limited in a bandpass filter 23, amplified in a buffer amplifier 24, and attenuated in a variable attenuation circuit 25. The transmission signal is further amplified in a driver amplifier 26, amplified in a power amplifier 28, and sent to a transmission antenna 30 via an isolator 29. The transmission antenna 30 emits the transmission signal, which is then carried to a user terminal 3 as a radio signal in a radio frequency band.

[0076] In the communication reception step S13, there is a case where a part of the transmission signal sent from the transmitting antenna 30 returns to the receiving antenna 11, and the received signal superimposed on the transmission signal sent from the user terminal 3 as a return signal is received by the receiving antenna 11. The receiving antenna 11 outputs the received signal to the processing unit 31 and the coupler 32.

[0077] In addition, in the communication reception step S13, directivity information of the transmitting antenna 30 or the receiving antenna 11 in the direction from an external terminal such as the user terminal 3 to a communication device such as the base station 2 may be acquired for each user terminal 3.

[0078] The received signal sent to the coupler 32 still contains a loop interference signal. In processing step S14, the coupler 32 performs processing to cancel the loop interference signal contained in the received signal. Specifically, the coupler 32 mixes the reference signal input from the processor 31 with the received signal containing the loop interference signal.

[0079] This reference signal is generated in processing step S14 with reference to the above-mentioned database 55. For example, the processor 31 may extract a feedback signal from the received signal, refer to one or more of the databases 55 generated in the generation step S12, and generate a reference signal having the same amplitude and opposite phase as a reference feedback signal that is equivalent to or similar to the extracted feedback signal from among the reference feedback signals included in the database 55. For this reason, by referring to the database 55 generated in advance in the generation step S12 and generating a reference signal having the same amplitude and opposite phase as the reference feedback signal, and superimposing this on the feedback signal, the feedback signal can be canceled.

[0080] Furthermore, the unit for processing the loop signal, including the coupler 32 and the processing unit 31, may be provided in any part of the receiving circuit 5. For example, the coupler 32 and the processing unit 31 may be connected to the mixer 15, and the filter 16 may be connected to the coupler 32. Any known method may be used to extract the loop signal from the received signal. It is not essential to obtain the loop signal from the received signal each time, and a reference loop signal contained in a database 55 generated in advance before the start of actual communication may be assumed to be the loop signal, and its amplitude and phase may be detected in advance.

[0081] Furthermore, when the processing unit 31 refers to one or more of the databases 55 generated in the generation step S12, the database 55 to be referred to may be selected depending on, for example, the communication environment. In such a case, for example, during a time period when the accuracy of wireless communication is low, such as during the day when the traffic is heavy, or when the reception and transmission sensitivity of the communication partner is low, the database 55 with the largest amount of information is selected from the multiple databases 55 and referred to, thereby enabling stable cancellation of the echo signal.

[0082] Furthermore, when the processing unit 31 refers to one or more of the databases 55 generated in the generating step S12, the database 55 to be referred to may be selected according to the directional information acquired in the communication receiving step S13, for example. In this case, it is possible to select an appropriate database 55 according to the directional information of the user terminal 3 that performs wireless communication. This makes it possible to cancel the loop signal stably against fluctuations and differences due to changes in directivity. Furthermore, in the processing unit 31, when the directional information of the user terminal 3 is the same as that of another user terminal 3 in the communication receiving step S11, the processing unit 31 may refer to the same database 55 as the database 55 corresponding to the other user terminal 3. For example, after the user terminal 3a and the base station 2 refer to the database 55a and cancel the loop signal to perform wireless communication, when the base station 2 performs wireless communication with the user terminal 3b having the same directional information as the user terminal 3a, the database 55a is referred to and the loop signal is canceled. In this case, wireless communication may be performed with user terminal 3b immediately after user terminal 3a, but this is not limited thereto, and the same database 55a may be referenced even when, for example, wireless communication with user terminal 3a is followed by wireless communication with user terminal 3c, and then wireless communication with user terminal 3b is performed. As a result, when wireless communication is performed with multiple user terminals 3, the same database can be shared between the user terminals 3 if the directional information is the same, and thus the burden of canceling the echo signal is reduced.

[0083] The amplitude of the loop interference signal may be measured via a power detector (not shown). As for the phase, the processing unit 31 temporarily sets the phase based on the reference loop interference signal, and then superimposes the loop interference signal on the reference loop interference signal. As a result, the user or the system may visually check to what extent the loop interference signal has been canceled, or the program may automatically detect the degree of reduction in the loop interference signal.

[0084] Then, the processing unit 31 resets the phase and similarly detects the degree of reduction in the loop signal compared to the previous time. As a result, if the loop signal has further decreased compared to the previous time, if the phase was increased during the resetting process, it is increased further, and if the phase was decreased during the resetting process, it is decreased further. Also, if the loop signal has increased compared to the previous time, if the phase was increased during the resetting process, it is decreased conversely, and if the phase was decreased during the resetting process, it is increased conversely.

[0085] In this way, the reference signal corresponding to the detected sneak signal may be generated before the signal is amplified by the amplifier 12, but the present invention is not limited to this. For example, the local oscillator circuit 8 may extract the sneak signal from the received signal, refer to the database 55, and generate the reference signal corresponding to the phase of the extracted sneak signal. The local oscillator circuit 8 may be equipped with a function for extracting the sneak signal from the received signal in the same manner as described above. Then, the local oscillator circuit 8 may generate a reference signal so that the phase is the same as the sneak signal, and the mixer 15 may mix the reference signal with the received signal to generate a converted signal. Since the phase has already been adjusted to match the sneak signal through mixing with the reference signal, the processor 21 only needs to adjust the amplitude of the reference signal in the same manner as described above to match the sneak signal.

[0086] In this way, the processing operation for canceling the loop interference signal can be classified into a method in which all adjustments of the amplitude and phase of the reference signal are performed on the receiving circuit 5 side, and a method in which the phase of the reference signal is adjusted and only the amplitude of the reference signal is adjusted on the receiving circuit 5 side.

[0087] Furthermore, the processor 31 may refer to the database 55 and generate a reference signal based on the transmission signal. In this case, the reference leakage signal and the reference transmission signal may be linked and recorded in the database 55, a reference transmission signal similar to or matching the transmission signal transmitted by the transmission circuit 6 may be selected from the database, and a reference signal having the same amplitude and opposite phase as the reference leakage signal linked to the selected reference transmission signal may be generated. This enables stable cancellation of the leakage signal against fluctuations and differences in the communication environment.

[0088] Although an embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. Such a novel embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope and spirit of the invention, and are included in the invention and its equivalents described in the claims. [Explanation of symbols]

[0089] 1. Wireless communication systems 2 base station 3. User terminal 4. Database Generator 5 Receiving circuit 6 Transmitting circuit 8 Local oscillator circuit 9 Antenna Isolation 10 Self-interference cancellation circuit 11 Receiving antenna 12 Amplifier 13 Receive Band Filter 14 Attenuator 15 Mixer 16 Filters 18 High Gain Amplifier 19 Attenuator 21 Attenuator 22 Mixer 23 Bandpass Filter 24 Buffer Amplifier 25 Variable attenuation circuit 26 Driver Amplifier 28 Power Amplifier 29 Isolator 30 Transmitting Antennas 31 Processing Equipment 32 Coupler 41 Reference Clock 42 Voltage Controlled Oscillator 43 Voltage Controlled Oscillator 50 Received information acquisition unit 51 Orientation information acquisition unit 52 Period Information Determination Unit 53 Cycle information determination section 54 Database Generation Section 55 Database 56 Recording Section 71 Transmitting Antenna 72 Receiving antenna 73 Baseband Digital Canceller 74 High Frequency Analog Canceller 75 Transmitting circuit 76 Receiving circuit 77 Database S11 Wraparound reception step S12 Generation Step S13 Communication reception step S14 Processing step

Claims

1. A database generation method for full-duplex communication, using a communication device having a transmitting antenna for transmitting a transmitting signal and a receiving antenna for receiving a receiving signal, and wirelessly communicating with an external terminal using full-duplex wireless communication, for generating a database for canceling a loop interference signal received by the receiving antenna from a transmitting signal transmitted by the transmitting antenna, comprising: a loop reception step of receiving only a reference loop signal received by the receiving antenna from the reference transmission signal transmitted by the transmitting antenna; a generation step of sampling the reference wraparound signal received by the wraparound reception step, and generating the database for recording the reference wraparound signal; The generating step sequentially generates the database so that the amount of information varies depending on at least one of period information on the length of a period during which the reference loop signal is received by the receiving antenna and period information on a period for sampling the reference loop signal. A method for generating a database for full-duplex communication, comprising:

2. The wraparound reception step acquires directional information regarding a direction of the transmitting antenna or the receiving antenna in a direction from the external terminal to the communication device, The generating step determines at least one of the period information and the period information according to the directivity information acquired by the wraparound reception step.

2. The method for generating a database for full-duplex communication according to claim 1 .

3. The generating step generates a database having the same amount of information as a database generated for the other directional information when the directional information acquired in the wraparound receiving step is the same as the other directional information.

3. The method for generating a database for full-duplex communication according to claim 2.

4. When the directional information acquired in the wraparound reception step is the same as other directional information, the generating step shares the database generated for the other directional information.

3. The method for generating a database for full-duplex communication according to claim 2.

5. 1. A full-duplex wireless communication method for performing full-duplex wireless communication between a communication device having a transmitting antenna for transmitting a transmission signal and a receiving antenna for receiving a reception signal, and an external terminal, comprising: a loop reception step of receiving only a reference loop signal received by the receiving antenna from the reference transmission signal transmitted by the transmitting antenna; a generating step of sampling the reference wraparound signal received by the wraparound signal receiving step, and sequentially generating a database for recording the reference wraparound signal; a communication receiving step of receiving a new reception signal including a loop interference signal by the receiving antenna; a processing step of referring to one or more of the databases generated by the generating step and canceling a loop interference signal included in the reception signal received by the communication receiving step; The generating step sequentially generates the database so that the amount of information varies depending on at least one of period information on the length of a period during which the reference loop signal is received by the receiving antenna and period information on a period for sampling the reference loop signal. A full-duplex wireless communication method comprising:

6. The generating step generates a database for each of the external terminals, The communication receiving step includes acquiring, for each of the external terminals, directivity information regarding a directivity of the transmitting antenna or the receiving antenna with respect to a direction toward the communication device; When the orientation information of the external terminal newly acquired in the communication receiving step is the same as the orientation information of another external terminal, the processing step refers to a database generated for the other external terminal.

6. The full-duplex wireless communication method according to claim 5,

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