Relay device, network node, control method, and program for improving location estimation accuracy

Abstract

To improve positioning accuracy in a wireless communication system in which a relay device is used.SOLUTION: The relay device that relays a wireless signal received from a terminal device to a base station device, when receiving from the terminal device a predetermined reference signal generated by using a first series, relays to the base station device a predetermined reference signal corresponding to a signal generated using a second series corresponding to the first series that is not used when the terminal device generates the predetermined reference signal.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a position estimation technique in a wireless communication system using a relay device. [Background technology]

[0002] In a cellular communication system, by identifying the location of a terminal device, it is possible to provide the terminal device with a communication service according to the location. The terminal device can identify its own location by measuring radio waves transmitted from an artificial satellite using, for example, a Global Navigation Satellite System (GNSS), and notify the network of the information via a base station device. On the other hand, there may be cases where the terminal device is unable to use GNSS-based positioning or where the GNSS-based positioning function is disabled. In such cases, for example, a method can be used in which multiple base station devices measure radio waves transmitted from the terminal device, and the location of the terminal device is estimated based on the timing at which the radio waves arrive (propagation time). Summary of the Invention [Problem to be solved by the invention]

[0003] In a cellular communication system, in order to increase the communication area, a relay device (e.g., a wireless repeater) may be used that amplifies and outputs radio waves received from a base station device or a terminal device. When a relay device is used, the relay operation within the relay device may lengthen the delay until the radio waves sent from the terminal device reach the base station device. This delay may cause the base station device to determine that the terminal device is located farther away than it actually is, resulting in a large positioning error. [Means for solving the problem]

[0004] The present invention provides a technique for improving positioning accuracy in a wireless communication system in which a relay device is used.

[0005] A relay device according to one aspect of the present invention includes relay means for relaying a radio signal received from a terminal device to a base station device, and control means for controlling the relay means, when a predetermined reference signal generated using a first sequence is received from the terminal device, to relay to the base station device a second sequence corresponding to the first sequence, the second sequence being not used when the terminal device generates the predetermined reference signal. When a signal different from the predetermined reference signal is received from the terminal device, the relay means amplifies the signal without demodulating it and transfers it to the base station device. .

[0006] A network node according to one embodiment of the present invention has an acquisition means for acquiring a timing when a predetermined signal sent from a terminal device is detected at a base station device, and an estimation means for estimating a position of the terminal device based on the timing, wherein when the predetermined signal generated using a first sequence is detected at the base station device, the estimation means estimates the position of the terminal device using the acquired timing, and when the predetermined signal corresponding to a signal generated using a second sequence corresponding to the first sequence, which is not used when the terminal device generates the predetermined signal, estimates the position of the terminal device using a corrected timing in which the timing is corrected so that the predetermined signal arrives earlier than the acquired timing by an amount related to relay processing in a relay device. Effect of the Invention

[0007] According to the present invention, it is possible to improve the positioning accuracy in a wireless communication system in which a relay device is used. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Diagram 2] FIG. 11 is a diagram illustrating an example of a relay process of an SRS. [Diagram 3]FIG. 2 illustrates an example of a hardware configuration of a relay device and a network node. [Figure 4] FIG. 2 illustrates an example of a functional configuration of a relay device. [Diagram 5] FIG. 2 is a diagram illustrating an example of a functional configuration of a network node. [Figure 6] FIG. 1 is a diagram illustrating an example of a flow of processing executed in a wireless communication system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] (System Configuration) FIG. 1 shows a configuration example of a wireless communication system according to the present embodiment. The wireless communication system may be a cellular communication system conforming to a cellular communication standard such as Long Term Evolution (LTE) or 5th Generation (5G) in which a terminal device connects to a base station device and performs wireless communication. It is assumed that the wireless communication system employs a relay device to improve wireless quality at a cell edge or a blind zone. FIG. 1 shows an example in which base station devices 101 to 103 and a terminal device 111 exist, and a relay device 121 is provided to relay communication of the base station device 103, for example. The terminal device 111 is configured to be able to connect to any of the base station devices 101 to 103 and perform communication. When the terminal device 111 connects to the base station device 103, the terminal device 111 establishes a connection via the relay device 121. It is noted that the relay device 121 may be, for example, a non-regenerative relay device (wireless repeater) that amplifies and outputs an incoming signal without performing demodulation or the like.

[0011] In this wireless communication system, each base station device detects a predetermined reference signal sent from the terminal device 111, and estimates the location of the terminal device 111 based on the detected timing. For example, the predetermined reference signal sent from the terminal device 111 is detected in each of the base station devices 101 to 103, and the detected timing is collected in a network node such as one of the base station devices or a positioning server prepared separately from these base station devices. Then, the network node can estimate the location of the terminal device 111 based on the difference in the reception timing of the predetermined reference signal at each base station device, based on the timing detected in, for example, three or more base station devices.

[0012] On the other hand, the base station device 103 receives the predetermined reference signal sent from the terminal device 111 via the relay device 121. For this reason, due to processing delays such as amplification and output by the relay device 121, the time until the predetermined reference signal sent from the terminal device 111 is received at the base station device 103 does not correspond to the length of the radio wave propagation path between the base station device 103 and the terminal device 111 via the relay device 121, and the error in the estimation result of the position of the terminal device 111 increases. On the other hand, if the network node can recognize that the predetermined reference signal has arrived at the base station device 103 via the relay device 121, it is possible to correct the reception timing of the predetermined reference signal at the base station device 103 by assuming that the predetermined reference signal has arrived at the base station device 103 earlier by the amount of the processing delay in the relay device 121. The timing after this correction corresponds to the length of the radio wave propagation path between the base station device 103 and the terminal device 111 via the relay device 121. In this case, the network node may perform location estimation by treating the predetermined reference signal from the terminal device 111 as having directly reached the base station device 103 at the corrected timing. Also, the network node may correct the corrected timing to a timing further advanced by a time corresponding to the distance between the base station device 103 and the relay device 121, and may treat the predetermined reference signal as having reached the relay device 121 at the re-corrected timing. Then, the network node may estimate the location of the terminal device 111 based on the difference in reception timing at the base station device 101, the base station device 102, and the relay device 121, thereby improving the accuracy of location estimation.

[0013] On the other hand, if the relay device 121 is a wireless repeater configured to amplify and transmit an incoming wireless signal without demodulating it, it is not possible to distinguish whether a signal arriving at the base station device 103 arrived directly from the terminal device 111 or arrived via the relay device 121. For this reason, the network node cannot appropriately correct the reception timing. In view of such circumstances, in this embodiment, the processing of the relay device 121 makes it possible to distinguish whether a signal arriving at the base station device 103 arrived directly from the terminal device 111 or arrived via the relay device 121, and to appropriately correct the reception timing.

[0014] When the relay device 121 of this embodiment receives a predetermined reference signal from the terminal device 111, the relay device 121 does not amplify and output the signal as is, but transmits the signal after performing a predetermined process to the base station device 103. For example, the predetermined reference signal sent from the terminal device 111 is generated using a first sequence specified for the terminal device 111 from the network side. In this case, when the predetermined reference signal arrives at a predetermined power level or higher, the base station device 103 can detect the predetermined reference signal using the first sequence. In this embodiment, the relay device 121 is also made to be able to detect the predetermined reference signal using the first sequence. Then, when the relay device 121 receives a predetermined reference signal generated using the first sequence, the relay device 121 relays to the base station device 103 a predetermined reference signal generated using a second sequence that corresponds to the first sequence and is different from the first sequence. Here, the second sequence may be a sequence that is not used when the predetermined reference signal is transmitted by the terminal device 111. According to this, when the base station device 103 detects a predetermined reference signal using the first sequence, it can determine that the predetermined reference signal arrived directly from the terminal device 111, and when the base station device 103 detects a predetermined reference signal using the second sequence, it can determine that the predetermined reference signal arrived via the relay device 121.

[0015] When the terminal device 111 transmits a predetermined reference signal, for example, a first sequence notified from the network side is used, but the sequence that can be used as the first sequence may have multiple patterns. For example, when the predetermined reference signal is a sounding reference signal (SRS), the terminal device 111 may use a predetermined sequence prepared in advance as the first sequence as is, or may use a sequence obtained by performing a cyclic shift on the predetermined sequence by a predetermined shift amount as the first sequence. Note that the cyclic shift is obtained by changing the head position of the predetermined sequence and adding a partial sequence existing before the head position to the end of the sequence. For example, by performing a cyclic shift of 10 on a sequence with a length of 100, in which each symbol is assigned an index of 0 to 99, the head position becomes 10, and a sequence in which a partial sequence with an index of 0 to 9 is added after the symbol with an index of 99 is obtained. Here, the SRS is transmitted for every predetermined number of subcarriers, but when the SRS is transmitted for every two subcarriers, eight shift amounts are defined, and eight sequences corresponding to the shift amounts can be used as the first sequence. In response to this, the relay device 121 can use a sequence different from any of the eight sequences as the second sequence. For example, eight second sequences corresponding to the eight first sequences can be prepared. Then, the relay device 121 can specify which of the eight first sequences was used to generate the reference signal received from the terminal device 111, specify a sequence corresponding to the specified sequence from among the second sequences, generate a predetermined reference signal using the specified second sequence, and transfer the generated reference signal to the base station device 103. Note that the second sequence can be a sequence unrelated to the specified sequence used when generating the first sequence. In addition, the second sequence can be a sequence orthogonal to the specified sequence used when generating the first sequence, in one example. By preparing second sequences corresponding to each of a plurality of sequences that can be used as a first sequence, it becomes possible to determine to which of a plurality of sequences that can be used as a first sequence a specific reference signal detected in base station device 103 corresponds, and to which terminal device the specific reference signal corresponds.

[0016] As described above, the predetermined reference signal may be an SRS. In this case, the first sequence may be the predetermined sequence itself or a sequence obtained by cyclic shifting the predetermined sequence by a first shift amount as described above. In this case, the second sequence may be a sequence obtained by cyclic shifting the predetermined sequence by a second shift amount that cannot be taken as the first shift amount. For example, when the first shift amount is 0, 10, 20, 30, and 40, the second shift amount may be set to 50, 60, 70, 80, and 90. In this case, for example, (first shift amount + 50) may be used as the second shift amount. The relay device 121 may identify the second shift amount from the first shift amount corresponding to the received SRS, and generate a new SRS using a sequence corresponding to the second shift amount. In this case, however, relay device 121 may modify the newly generated SRS in a format that reflects the reception quality and the like in the received SRS, i.e., in a format that does not lose the characteristics of the SRS received from terminal device 111, and transmit the modified SRS to base station device 103. Note that relay device 121 may modify the received SRS by performing a cyclic shift of a corresponding shift amount on the received SRS, and transmit an SRS corresponding to the second shift amount to base station device 103 without generating a new SRS.

[0017] By detecting a peak of a value calculated by correlation detection using a known sequence, it is detected that a predetermined signal using the known sequence has been transmitted. In contrast, when a different sequence is generated by performing a cyclic shift on a predetermined sequence, when correlation detection is performed on a predetermined signal generated using the different sequence, a peak may occur at a timing shifted by a time corresponding to the shift amount. In this case, if the timing shift at which a peak occurs in correlation detection using a predetermined sequence is included within the range of a cyclic prefix added to one OFDM (orthogonal frequency division multiplexing) symbol, an error may occur in determining which shift amount corresponds to the peak. That is, it is assumed that a certain delayed wave is generated for an OFDM symbol generated by a certain sequence, and therefore a cyclic prefix is ​​added, so when correlation detection is performed using that sequence, a peak corresponding to the delayed wave is detected within the range of the cyclic prefix. On the other hand, when correlation detection is performed using a different sequence obtained by performing a cyclic shift on that sequence, a peak occurs with a shift in timing. At this time, if the amount of cyclic shift is not large enough, the timing shift is not large, and a peak may occur at the same timing as the delayed wave, for example. In this case, it becomes impossible to determine whether the peak that appears corresponds to the sequence before the cyclic shift or the sequence after the cyclic shift. Therefore, in this embodiment, the shift amount can be set so that the difference in the peak appearance timing exceeds the length of the cyclic prefix of the SRS. Note that this shift amount can also be applied to the relationship between two second sequences.

[0018] In addition, such a shift amount is specified based on, for example, the length of the cyclic prefix, and in one example, a maximum of 14 shift amount patterns can be obtained. By utilizing this, for example, in the SRS transmitted from the above-mentioned terminal device 111, 7 (or less) of the 14 patterns can be used as the first shift amount, and in the SRS transferred by the relay device 121, the remaining 7 (or less) of the 14 patterns can be used as the second shift amount. For example, indexes 0 to 13 can be assigned to each of the 14 patterns, and patterns with indexes 0 to 6 can be used as the first shift amount, and a pattern of "index of the first shift amount + 7" can be used as the second shift amount. This makes it possible to determine that when a reference signal generated using a first sequence corresponding to a shift amount pattern of indexes 0 to 6 is detected, the signal is a signal that has arrived directly from the terminal device 111, and when a reference signal generated using a second sequence corresponding to a shift amount pattern of indexes 7 to 13 is detected, the signal is a signal relayed by the relay device 121. For example, the second shift amount may be a shift amount obtained by adding a shift amount exceeding the maximum value of the first shift amount to the first shift amount. That is, when a predetermined reference signal corresponding to a sequence having a shift amount exceeding the maximum value of the first shift amount is detected, the signal may be determined to be a signal relayed by the relay device 121.

[0019] An overview of the operation of relay device 121 when performing such processing is shown in FIG. 2. Note that, here, it is assumed that a sequence with indexes 0 to X-1 (X≧6) is used as a first sequence, and a sequence with indexes X to 2X-1 is used as a second sequence. Note that, in one example, indexes 0 to 2X-1 may correspond to different shift amounts. In this case, the first sequence and the second sequence are generated as sequences obtained by applying a cyclic shift to the same predetermined sequence by different shift amounts. Also, the first sequence and the second sequence may be sequences obtained by applying a cyclic shift to different predetermined sequences. Also, sequences corresponding to different indices within the range of the first sequence or the range of the second sequence may be mutually unrelated sequences that are not in a cyclic shift relationship. Note that, in FIG. 2, it is assumed that a sounding reference signal (SRS) is used as the predetermined reference signal, and the first sequence and the second sequence are sequences obtained by applying a cyclic shift to a common predetermined sequence by different shift amounts.

[0020] In FIG. 2, it is assumed that terminal device 111 and terminal device 112 are located in positions where they can communicate with base station device 103 via relay device 121, and terminal device 113 is located in a position where they can communicate directly with base station device 103. At this time, for example, a connected base station device may notify each terminal device of information (e.g., a first shift amount) that enables generation of a first sequence with indexes 0 to X-1 as a sequence to be used when generating an SRS. Also, information (e.g., a second shift amount and a shift amount to be added to the first shift amount) that enables generation of a second sequence corresponding to each of the first sequences with indexes 0 to X-1 may be notified from a base station device that is a relay target of communication. Then, terminal device 111 generates and transmits an SRS using a sequence with index "1", terminal device 112 uses a sequence with index "5", and terminal device 113 uses a sequence with index "3". At this time, the SRS transmitted from terminal device 113 arrives directly at base station device 103 as is. Base station device 103 performs SRS detection processing using each of the sequences with indexes "1" to "X-1", and is thereby able to detect the SRS from terminal device 113 that was generated using the sequence with index "3". This allows base station device 103 to identify that the SRS from terminal device 113 has arrived directly and has not passed through relay device 121.

[0021] Meanwhile, the SRSs transmitted from the terminal device 111 and the terminal device 112 are relayed by the relay device 121. In this case, since the SRS received from the terminal device 111 was generated using the first sequence with index "1", the relay device 121 transfers the SRS corresponding to the second sequence with index "1+X" corresponding to index "1" to the base station device 103. Note that the relay device 121 generates the SRS using the second sequence with index "1+X" or modifies the received SRS by performing a cyclic shift by the shift amount corresponding to index "X", and outputs the generated or modified SRS. Similarly, since the SRS received from the terminal device 112 was generated using the first sequence with index "5", the relay device 121 transfers the SRS corresponding to the second sequence with index "5+X" corresponding to index "5" to the base station device 103. Base station device 103 can detect SRS corresponding to a sequence with index "1+X" or "5+X" by performing SRS detection processing using each of the sequences with indexes "X" to "2X-1". When base station device 103 detects an SRS corresponding to a sequence with index "1+X", it can identify that the SRS has been received via relay device 121. When base station device 103 detects an SRS corresponding to a second sequence with index "1+X", it can identify that the SRS corresponds to a first sequence with index "1". Since terminal device 111 is set to use the first sequence with index "1", base station device 103 can identify that the SRS has been transmitted from terminal device 111 and received via relay device 121. Similarly, when the base station device 103 detects an SRS corresponding to a sequence with an index of “5+X”, it can determine that the SRS was sent from the terminal device 112 and received via the relay device 121.Then, the base station device 103 or the network node performing positioning can improve the positioning accuracy of the terminal device 111 and the terminal device 112 by treating the reception timing at which the SRS was actually received via the relay device 121 as being earlier by the amount of the processing delay caused by the relay device 121 (by correcting the reception timing).

[0022] The above-mentioned SRS is an example of a predetermined reference signal, and another reference signal may be used. For example, a reference signal newly defined for position measurement may be used. The first sequence and the second sequence do not have to be sequences generated by performing a cyclic shift on a predetermined sequence. That is, it is sufficient that a predetermined reference signal is generated by a sequence selected from predetermined candidates so as to be detectable in the base station device, the first sequence and the second sequence are different from each other, and the first sequence and the second sequence are mapped one-to-one.

[0023] In order to execute the above-mentioned process, the relay device 121 has a function of at least identifying a predetermined reference signal, modifying and amplifying the predetermined reference signal, and outputting the modified and amplified signal. For example, the relay device 121 may execute a demodulation process on the received predetermined reference signal to identify a first sequence, generate a second sequence by further performing a cyclic shift on the first sequence, and regenerate and relay the predetermined reference signal based on the second sequence. In addition, when the relay device 121 identifies the first sequence used when the received predetermined reference signal is generated, the relay device 121 may transmit a predetermined reference signal prepared separately using a second sequence corresponding to the first sequence to the base station device 103 instead of the received reference signal. In addition, the relay device 121 may be configured to output a predetermined reference signal based on a modified or separately prepared second sequence after a predetermined time has elapsed since the reception timing of the predetermined reference signal.

[0024] Furthermore, for signals other than a predetermined reference signal, the relay device 121 can function as a wireless repeater, amplifying the signal without performing demodulation processing on the signal and transferring it to the base station device 103. That is, the relay device 121 has a function for performing the above-mentioned processing on a predetermined reference signal, and can function as a wireless repeater that performs non-regenerative relay on other signals.

[0025] (Device configuration) FIG. 3 is a diagram showing an example of a hardware configuration of the relay device 121. In one example, the relay device 121 includes a processor 301, a ROM 302, a RAM 303, a storage device 304, and a communication circuit 305. The processor 301 is a computer including one or more processing circuits such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and executes the overall processing of the device and each of the above-mentioned processes by reading and executing a program stored in the ROM 302 or the storage device 304. The ROM 302 is a read-only memory that stores information such as a program related to the processing executed by the relay device 121 and various parameters. The RAM 303 functions as a workspace when the processor 301 executes a program, and is a random access memory that stores temporary information. The storage device 304 is, for example, a removable external storage device. The communication circuit 305 is, for example, a circuit for wireless communication of LTE or 5G. 2, one communication circuit 305 is illustrated, but the relay device 121 may have multiple communication circuits. For example, the relay device 121 may have wireless communication circuits and antennas for LTE and 5G.

[0026] Note that a network node (for example, any base station device or a positioning server) that estimates the position of the terminal device 111 may also have a hardware configuration similar to that in FIG.

[0027] 4 is a diagram showing an example of the functional configuration of relay device 121. Relay device 121 includes, for example, relay processing unit 401, SRS detection unit 402, and SRS transformation unit 403. These functional units may be implemented, for example, by processor 301 executing a program stored in ROM 302 or storage device 304. However, this is not limited to the above, and for example, some or all of these functional units may be implemented using dedicated hardware. Note that the processes to be executed by relay device 121 have been described above, so the functional configuration of relay device 121 will be merely roughly outlined here.

[0028] Relay processing unit 401 amplifies a signal received from terminal device 111 and transmits it to base station device 103, and also amplifies a signal received from base station device 103 and transmits it to terminal device 111. Relay device 121 is, for example, a non-regenerative relay device (wireless repeater), and relay processing unit 401 is configured to amplify (and frequency convert as necessary) signals other than a predetermined reference signal used for positioning such as SRS without demodulating and decoding them, and output them. Note that when relay device 121 is a regenerative relay device, relay processing unit 401 can be configured to demodulate and decode the received signal, encode and modulate the data sequence obtained thereby, and regenerate and output the radio signal.

[0029] The SRS detection unit 402 performs an SRS detection process in a frequency and time resource in which an SRS (a predetermined reference signal) can be transmitted. For example, the SRS detection unit 402 performs correlation detection using a first sequence that can be used when the terminal device 111 generates an SRS in that frequency and time resource, and can determine that an SRS has arrived when a peak appears in the correlation value. When an SRS is detected by the SRS detection unit 402, the SRS modification unit 403 modifies the SRS into a format that allows the base station device 103 to identify that the SRS has arrived via the relay device 121. For example, the SRS modification unit 403 can perform a cyclic shift by a predetermined shift amount on the first sequence corresponding to the received SRS, and output an SRS corresponding to a second sequence that is not used by the terminal device 111 to transmit the SRS. Note that the SRS modification unit 403 may generate a new SRS, for example, by using a second sequence corresponding to the first sequence used in detecting the SRS in the SRS detection unit 402. The transformed or newly generated SRS output by the SRS transformation section 403 is transmitted to the base station apparatus 103 via the relay processing section 401 .

[0030] 5 is a diagram showing an example of a functional configuration of a network node that estimates the position of the terminal device 111. The network node includes, for example, a timing information acquisition unit 501 and a position estimation unit 502. Note that these functional units can be implemented, for example, by the processor 301 executing a program stored in the ROM 302 or the storage device 304. However, this is not limiting, and for example, some or all of these functional units may be implemented using dedicated hardware.

[0031] The timing information acquisition unit 501 acquires information on the timing at which an SRS (predetermined reference signal) from a terminal device is detected in each base station device. The timing information acquisition unit 501 acquires, for example, information indicating the timing at which the SRS was actually received from a base station that received the SRS directly from the terminal device 111. Also, the timing information acquisition unit 501 acquires, for example, information indicating the timing corrected so that the SRS arrives earlier than the timing at which the SRS was actually received by a time related to the relay process in the relay device 121 from a base station that received the SRS from the terminal device 111 via the relay device 121. The timing information acquisition unit 501 may acquire, from the base station that received the SRS from the terminal device 111 via the relay device 121, information indicating the timing at which the SRS was actually received and information capable of identifying that the SRS was received via the relay device 121. In this case, the timing information acquisition unit 501 may correct the timing by a time related to the relay process in the relay device 121 so that the SRS arrives earlier than the timing at which the SRS is actually received, and may acquire the corrected timing information. The time related to the relay process in the relay device 121 may be, but is not limited to, the time required for the relay process itself. For example, the time related to the relay process may include a time corresponding to an expected value of a path difference between the straight-line distance from the position of the terminal device 111 to the position of the base station device and the distance of the path from the terminal device 111 to the base station device when the SRS is received via the relay device 121. For example, the positions of at least some of the terminal devices whose communication is relayed by the relay device 121 are measured in advance using GNSS or the like, and the expected value of the path difference may be specified from the distribution of the results. In one example, when the SRS is received via relaying by the relay device 121, the timing may be corrected so that the SRS arrives at the base station device earlier than the actual reception timing by the expected value of the path difference.

[0032] The position estimation unit 502 performs positioning based on, for example, the time difference of arrival (TDOA). That is, the position estimation unit 502 estimates the position of the terminal device 111 based on the reception timing difference of the SRS from the terminal device 111 acquired from a plurality of (for example, three) base station devices by the timing information acquisition unit 501. Note that the position estimation unit 502 performs position estimation based on TDOA using the timing at which the SRS was actually received when the SRS arrived at the base station device without being relayed by the relay device 121, and using the corrected timing obtained as described above when the SRS was received via relaying by the relay device 121.

[0033] (Processing flow) Next, an example of the flow of processing executed in the wireless communication system will be described with reference to Fig. 6. In this example, a process will be described in which, when an SRS is received in each base station device, it is determined whether the SRS is received via the relay device 121, and if the SRS is received via the relay device 121, the reception timing is corrected. That is, the process in which the network node actually executes the location estimation of the terminal device 111 is different from the conventional one only in that the location estimation is performed using the corrected timing for the SRS received via the relay device 121, and therefore the description here will be omitted.

[0034] In the example of FIG. 6, the terminal device 111 generates an SRS using a first sequence (for example, a sequence of index n (0≦n≦X−1)) and transmits it to the surroundings (S601). The base station device 101 and the base station device 102 detect the SRS and recognize that the SRS corresponding to the sequence of index n has been received, and determine that the SRS has not been relayed by a relay device and that there is no effect of delay due to the relay process (S602). For this reason, the base station device 101 and the base station device 102 do not perform a correction process of the reception timing. Meanwhile, the base station device 103 receives the SRS via the relay device 121. In this case, in response to receiving the SRS generated using the first sequence of index n, the relay device 121 modifies the SRS or generates a new SRS using a second sequence of index n+X corresponding to the index n, and transmits the modified or generated SRS to the base station device 103 (S603). The base station device 103 detects the SRS and recognizes that the SRS corresponding to the sequence of index n+X has been received. The base station device 103 determines that the detected SRS has been relayed by the relay device 121 and that there is an effect of delay due to the relay process (S604). The base station device 103 then corrects the reception timing to treat it as if the reception timing was earlier by the amount of delay due to the relay process (S605).

[0035] In one example, the base station devices 101 to 102 provide a predetermined network node (for example, one of the base station devices or a positioning server) with the timing at which the SRS was actually received, and the base station device 103 provides the corrected reception timing to the network node. The network node can then estimate the location of the terminal device 111 based on the reception time difference based on the provided information on the reception timing of the SRS. The base station devices 101 to 103 also provide the network node with information indicating the timing at which the SRS was actually received and information indicating the sequence used when detecting the SRS, and the network node can determine whether or not to correct the timing based on the information and execute location estimation of the terminal device 111.

[0036] In this manner, in this embodiment, the reception timing of the SRS from the terminal device 111 is identified by removing the effect of delay caused by the relay process by the relay device 121, so that it is possible to improve the estimation accuracy of the location of the terminal device 111. This makes it possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0037] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

Claims

1. A relay device, A relay unit that relays a radio signal received from a terminal device to a base station device; a control means for controlling the relay means, when a predetermined reference signal generated using a first sequence is received from the terminal device, to relay to the base station device the predetermined reference signal corresponding to a signal generated using a second sequence corresponding to the first sequence, the second sequence being not used when the terminal device generates the predetermined reference signal; having The relay device is characterized in that when a signal different from the specified reference signal is received from the terminal device, the relay means amplifies the signal without performing demodulation processing on the signal and transfers it to the base station device.

2. 2. The relay device according to claim 1, wherein the first sequence is a sequence obtained by performing a cyclic shift on a predetermined sequence by a first shift amount or the predetermined sequence itself, and the second sequence is a sequence obtained by performing a cyclic shift on the predetermined sequence by a second shift amount that is not used as the first shift amount.

3. 3. The relay device according to claim 2, wherein the second shift amount has a magnitude obtained by adding a shift amount exceeding a maximum value of the first shift amount usable when generating the first sequence to the first shift amount.

4. 4. The relay device according to claim 2, wherein the number of patterns of the first shift amount and the second shift amount is set based on a length of a cyclic prefix added to an orthogonal frequency division multiplexing (OFDM) symbol.

5. The relay device according to claim 1 , wherein the predetermined reference signal is a sounding reference signal (SRS).

6. A network node, an acquisition means for acquiring a timing at which a predetermined signal transmitted from a terminal device is detected by a base station device; an estimation means for estimating a position of the terminal device based on the timing; having The estimation means includes: When the predetermined signal generated using a first sequence is detected at the base station device, estimating a position of the terminal device using the acquired timing; when a predetermined signal corresponding to a signal generated using the second sequence corresponding to the first sequence and not used when the terminal device generates the predetermined signal is detected in the base station device, the position of the terminal device is estimated using a corrected timing in which the timing is corrected so that the predetermined signal arrives earlier than the acquired timing by a time related to a relay process in a relay device. A network node comprising:

7. A control method executed by a relay device having a relay unit that relays a radio signal received from a terminal device to a base station device, comprising: controlling the relay means to relay, when a predetermined reference signal generated using a first sequence is received from the terminal device, to the base station device, the predetermined reference signal corresponding to a signal generated using a second sequence corresponding to the first sequence, the second sequence being not used when the terminal device generates the predetermined reference signal; A control method in which, when a signal different from the predetermined reference signal is received from the terminal device, the relay device amplifies the signal without performing demodulation processing on the signal and transfers it to the base station device.

8. A control method performed by a network node, comprising the steps of: acquiring a timing at which a predetermined signal transmitted from a terminal device is detected by a base station device; estimating a location of the terminal device based on the timing; and Including, In the above estimation, When the predetermined signal generated using a first sequence is detected at the base station device, estimating a position of the terminal device using the recorded timing; when a predetermined signal corresponding to a second sequence corresponding to the first sequence and generated using the second sequence that is not used when the terminal device generates the predetermined signal is detected in the base station device, the position of the terminal device is estimated using a corrected timing in which the timing is corrected so that the predetermined signal arrives earlier than the recorded timing by a time related to a relay process in a relay device. A control method comprising:

9. A program for causing a computer to function as the relay device according to any one of claims 1 to 5.

10. A program for causing a computer to function as the network node according to claim 6.

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