Communication relay system, communication relay method, and program

Abstract

To reduce the difference in propagation delay time between a base station and a terminal device in a communication relay system.SOLUTION: In a communication relay system of an embodiment, a parent station device acquires a duplexing method for each of a plurality of downlink signals from a base station by detecting it from the downlink signals or from setting information, detects first timings indicating predetermined timings for the plurality of respective downlink signals, estimates second timings indicating predetermined timings for the plurality of respective downlink signals based on the plurality of first timings and the acquired duplexing methods, selects timing reference values from the plurality of second timings, adjusts each of the plurality of downlink signals based on the timing reference values and the second timings, and adjusts each corresponding uplink signal using an adjusted amount obtained by adjusting each of the plurality of downlink signals.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a communication relay system, a communication relay method, and a program. [Background technology]

[0002] Known wireless transmission methods used in wireless communication terminals (hereinafter also referred to as "terminal devices") such as mobile phones and smartphones include the FDD (Frequency Division Duplex) method, which uses two different frequency bands as a pair, respectively as a downlink signal and an uplink signal, and the TDD (Time Division Duplex) method, which shares the same frequency band for both the downlink and uplink signals and uses them in a time-division manner.

[0003] Also, a method is known in which a communication relay system (repeater system) is shared by a plurality of businesses (carriers: communication service providers) to enable wireless communication terminals to be used in blind areas such as indoors. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-006163 [Patent Document 2] Patent No. 6602813 Summary of the Invention [Problem to be solved by the invention]

[0005] Furthermore, in recent years, the introduction of technologies such as Carrier Aggregation (CA) and Dual Connectivity (DC), which use multiple communication bands, has been promoted as a measure to increase information capacity and improve communication quality.

[0006] In order to apply CA or DC to a communication relay system, it is necessary to keep the propagation delay time difference between the base station and the terminal device within a predetermined time (specified time) that can be controlled by the terminal device. However, depending on the arrangement of each device (base station, parent station device, child station device, etc.) in the communication relay system, conventional technology may not be able to keep the propagation delay time difference between the base station and the terminal device within the predetermined time.

[0007] Therefore, the present invention has been made in consideration of the above circumstances, and its objective is to provide a communication relay system, a communication relay method, and a program that can reduce the propagation delay time difference between a base station and a terminal device. [Means for solving the problem]

[0008] According to an embodiment, a communication relay system relays communications between a base station and a wireless communication terminal, the communication relay system comprising: a master station device that receives downlink signals of wireless signals from the base station; and a plurality of slave station devices that are connected to the master station device and receive uplink signals of wireless signals from the wireless communication terminal. The master station device acquires a duplex mode for each of the downlink signals from the base station by detecting the duplex mode from configuration information or from the downlink signals, detects first timings that indicate predetermined timings for each of the downlink signals, estimates second timings that indicate predetermined timings for each of the downlink signals based on the first timings and the acquired duplex modes, selects timing reference values ​​from the second timings, adjusts each of the downlink signals based on the timing reference value and the second timing, and adjusts each of the corresponding uplink signals using an adjustment amount obtained by adjusting each of the downlink signals. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a communication relay system and the like according to the prior art and the first embodiment. [Figure 2]FIG. 2 is a schematic diagram of a communication relay system and the like according to the prior art and the second embodiment. [Figure 3] FIG. 3 is a diagram showing the general configuration of the master station device of the first embodiment. [Figure 4] FIG. 4 is a flowchart showing the processing of the master station device of the first embodiment. [Figure 5] FIG. 5 is a diagram showing the general configuration of a master station device according to a first modification of the first embodiment. [Figure 6] FIG. 6 is a diagram showing the general configuration of a master station device according to the second modification of the first embodiment. [Figure 7] FIG. 7 is a diagram showing the general configuration of an RFU according to the second modification of the first embodiment. [Figure 8] FIG. 8 is a diagram showing the general configuration of a master station device according to the second embodiment. [Figure 9] FIG. 9 is a flowchart showing the processing of the master station device according to the second embodiment. [Figure 10] FIG. 10 is a diagram showing the general configuration of a master station device according to a first modification of the second embodiment. [Figure 11] FIG. 11 is a diagram showing the general configuration of a master station device according to a second modification of the second embodiment. [Figure 12] FIG. 12 is a diagram showing the general configuration of a master station device according to the third embodiment. [Figure 13] FIG. 13 is a flowchart showing the processing of the master station device according to the third embodiment. [Figure 14] FIG. 14 is a diagram showing the general configuration of a master station device according to the fourth embodiment. [Figure 15] FIG. 15 is a flowchart showing the processing of the master station device according to the fourth embodiment. [Figure 16] FIG. 16 is a flowchart showing the processing of the master station device according to the sixth embodiment. [Figure 17] FIG. 17 is a flowchart showing processing by a master station device according to a modification of the sixth embodiment. [Figure 18] FIG. 18 is a schematic diagram of a conventional communication relay system. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, with reference to the drawings, embodiments of the communication relay system, communication relay method, and program of the present invention will be described in detail. First, to facilitate understanding of the embodiments, the prior art will be described in detail again. Also, in Figures 1, 2, and 18, the communication relay system in the narrow sense is the range indicated by the reference numeral 1000, while the communication relay system in the broad sense is the entire range. In other words, hereinafter, even when the term "communication relay system 1000" is used, it may also refer to the communication relay system in the broad sense.

[0011] In recent years, the demand for mobile communications has increased dramatically due to the spread of smartphones and the development of corporate DX (Digital Transformation). As a result, in addition to the conventional LTE (Long Term Evolution), the deployment of 5G (5th Generation: 5th generation mobile communications system), which has higher throughput than LTE, is progressing.

[0012] In recent years, CA and DC technologies that use multiple communication bands have been introduced as a way to increase information capacity and improve communication quality (NTT DOCOMO, Technical Journal, vol. 23 No. 2, Vol. 18 No. 2; LTE, vol. 26 No. 3).

[0013] The specifications of 3GPP (Third Generation Partnership Project) (registered trademark) are defined so that CA can be performed regardless of the FDD / TDD duplex method, and DC can be performed regardless of the communication method such as LTE or 5G NR (New Radio).

[0014] To perform CA or synchronous mode DC, it is necessary to keep the propagation delay time difference of the path from the base station to the terminal device for each communication band (hereinafter also referred to as "radio signal") within a predetermined time (specified time) that can be controlled by the terminal device. According to 3GPP TR (Technical Report) 36.300, the upper limit of the propagation delay time difference of this path that the terminal device can tolerate is approximately 30 μs (microseconds). In the case of 5G NR, the upper limit is smaller than this 30 μs depending on the subcarrier frequency.

[0015] Also, a communication relay system (repeater system) is known that enables a terminal device to be used in a blind area such as indoors, etc. Fig. 18 is a schematic diagram of a communication relay system 1000 or the like of the prior art.

[0016] A master station device 100 (MU: Main Unit), slave station devices 200 and 210 (RU: Remote Unit), and an antenna 300 (ANT) are arranged in the communication relay system 1000. In a service area 510 corresponding to the antenna 300, a user can use a terminal device 500 (UE: User Equipment: wireless communication terminal).

[0017] In addition to the master station device 100, the equipment installation area 1100 also includes a base station 600 (BS: Base Station) and a base station system 710 (RRH: Remote Radio Head).

[0018] Furthermore, a baseband signal processing device 700 (BBU: Base Band Unit) arranged in the equipment installation area 2000 is connected to the core network 4000 and the base station system 710. Furthermore, the transmission paths connecting the devices are as shown in the figure.

[0019] For example, in densely populated spaces such as inside buildings or underground malls, or indoor spaces where the effects of multipath interference are significant, the deployment of 5G NR and the application of CA and DC technologies in addition to conventional LTE are effective in improving throughput and communication quality.

[0020] In order to apply CA and DC to the communication relay system 1000, the propagation delay time difference in the communication relay system 1000 between Component Carriers (CC: radio signals) to which CA and DC are applied must be kept within a specified time (specified time) that is acceptable to the terminal device.

[0021] Furthermore, a base station 600 is usually installed near the master station device 100, and the base station 600 and the antenna port of the master station device 100 are connected for each different radio signal by a coaxial cable or the like. Therefore, the propagation delay time difference between radio signals can be kept below a predetermined value, preferably to zero, by managing the length of the coaxial cable and managing the propagation delay time difference within the communication relay system 1000.

[0022] However, in the communication relay system 1000, it is usually necessary to install the devices in a place with limited installation space, such as a machine room in a building or an underground mall, and therefore it may not be possible to install the base station (or a part of the base station) close to the master station device. In this case, for example, it may be possible to install the base station in the facility of the operator, and install a wireless function unit housed in the master station device, such as an RFU (Radio Function Unit), at a distance from the master station device.

[0023] This situation will be explained using Figure 1. Figure 1 is a schematic diagram of a conventional communication relay system, etc. Explanations of matters similar to those in Figure 18 will be omitted where appropriate.

[0024] In addition to the master station device 100, a base station 600 and a base station system 710 are also placed in the equipment installation area 1100. In this case, the base station 600 and the master station device 100, and the base station system 710 and the master station device 110 are each connected by a transmission path 3100. The transmission path 3100 is wiring inside the equipment installation area 1100, and is several meters long.

[0025] Furthermore, because there is no space to install other base stations in the equipment installation area 1100, the base station 610 and base station system 720 are installed in the equipment installation area 2200-1, and the base station 640 is installed in the equipment installation area 2200-m. The base station 610 and base station system 720 are connected to the master station device 100 via an RFU 400, which has some of the master station functions, and a transmission path 3200. The base station 640 is connected to the master station device 100 via the RFU 400 and the transmission path 3200.

[0026] The transmission path 3200 may be several kilometers long, in which case the propagation delay time is on the order of μs. In the master station device 100, a difference in propagation delay time occurs due to the difference in length between the transmission path 3200 and the transmission path 3100, which can cause a problem that the difference in propagation delay time at the terminal device 500 does not fall within a predetermined time (specified time).

[0027] In addition, it is possible to install a 5G NR-compatible repeater system alongside an existing LTE-compatible repeater system. In this case, there is no way to manage the propagation delay time difference between the LTE-compatible repeater system and the 5G NR-compatible repeater system, which means that DC between LTE and 5G NR cannot be achieved.

[0028] This problem will be described in detail with reference to Fig. 2. Fig. 2 is a schematic diagram of a conventional communication relay system, etc. Explanations of matters similar to at least either Fig. 18 or Fig. 1 will be omitted as appropriate.

[0029] 2 assumes a case where a 5G NR-compatible repeater system is newly added to an LTE-compatible repeater system. To support the 5G NR-compatible repeater system, a 5G NR-compatible master station device 100-3 and a 5G NR-compatible slave station device 220 are installed. The slave station devices 200 and 210 are LTE-compatible slave station devices.

[0030] An LTE base station 620 (eNB: evolved Node B) and a 5G NR base station 630 (gNB: next generation Node B) are installed in the same equipment installation area 1100 as the base station device 100-3, and are connected to the base station device 100-3 via a transmission path 3100. For this reason, there is almost no difference in propagation delay time between the base station 620 and the base station device 100-3 and between the base station 630 and the base station device 100-3.

[0031] Also, consider a case where the slave station device 200 (the lower of the two; the same applies below) and the slave station device 220 provide LTE and 5G NR DC to a service area 520 via the antennas 300 and 320. In this case, the LTE-compatible slave station device 200 is connected to the master station device 100-3 via the slave station device 210 via a transmission path 1210. Furthermore, the 5G NR-compatible slave station device 220 is connected to the master station device 100-3 via a transmission path 1220.

[0032] For this reason, the propagation delay time between the master station device 100-3 and the slave station device 220 is different from the propagation delay time between the master station device 100-3 and the slave station device 200. Therefore, the LTE radio signal passing through antenna 300 (the lowest of the three; the same applies below) and the 5G NR radio signal passing through antenna 320 already have different propagation delay times from the master station device 100-3 to antenna 300 and antenna 320, and therefore the propagation delay times from base station 620 and base station 630 to the terminal device 500 in the service area 520 are different. For this reason, there is a problem that DC cannot be applied, or even if it can be applied, it is limited to the limited range of the service area 520.

[0033] CA and DC can be configured regardless of the duplexing method, FDD or TDD. In conventional repeater systems, technology for matching TDD switching timing has been proposed (for example, Patent No. 6602813), but there is a problem in that it is necessary to detect timing including not only TDD but also FDD, and to keep the propagation delay time difference below a predetermined value, preferably zero.

[0034] In particular, in a shared repeater system that handles multiple operators, it is necessary to synchronize the TDD timing between operators. If the transmission and reception timing between operators is out of sync, there is a problem of interference between them. In contrast, with FDD, the DL (Down Link) band from the base station to the terminal device and the UL (Up Link) band from the terminal device to the base station are different, so there is no problem of interference even if the timing is out of sync. However, with CA and DC, there is a problem in that the timing including FDD must be detected and the propagation delay time difference must be kept below a certain value, preferably zero.

[0035] CA and DC can be implemented in the DL direction from the base station to the terminal device and in the UL direction from the terminal device to the base station by commands from the base station. To implement CA and DC in the UL direction, the propagation delay time difference in the UL direction from the terminal device to the base station must be within the allowable range, preferably zero. For this reason, there are cases where CA and DC in the UL direction cannot be implemented simply by adjusting the propagation delay time difference in the DL direction.

[0036] Furthermore, even if the propagation delay time in the DL direction is matched, if the propagation delay time in the UL direction is not also matched, this will affect the calculation of TA (Timing Advance), which adjusts the reception timing and transmission timing in terminal devices in the UL and DL directions, and in the worst case scenario, the terminal device will not be able to connect to the base station.

[0037] The above can be summarized as follows: The frame length is the same for FDD and TDD. The frame length is also the same for LTE and 5G.

[0038] *If the base stations performing CA or DC are installed far away, CA / DC may not be possible even if the propagation delay time within the repeater system is managed. *When performing CA or DC between FDD / TDD duplexing methods, it is necessary to take into account the timing of TDD switching and synchronize the timing with FDD to transmit to the terminal device. *The timing between the LTE system and the 5G NR system must be synchronized before transmission to the terminal device. *It is necessary to balance the propagation delay time in the DL direction and the propagation delay time in the UL direction.

[0039] Therefore, in the following, a technology that can be improved in view of the above circumstances will be described. That is, a technology that can reduce the propagation delay time difference between a base station and a terminal device compared to conventional technology will be described. Note that in the following explanations of the embodiments and modifications, explanations of matters that are the same as those that have been explained up to that point will be omitted as appropriate. Also, for the sake of brevity, constituent symbols may be omitted.

[0040] (First embodiment) The first embodiment is based on Fig. 1. Fig. 3 is a schematic diagram of the master station device 100 of the first embodiment.

[0041] The communication relay system 1000 is a communication relay system that relays communication between a base station (for example, base stations 600, 610, 640, base station systems 710, 720; the same applies below) and a terminal device 500 (wireless communication terminal). The communication relay system 1000 includes a master station device 100 that receives a downlink signal of a wireless signal from the base station, and a plurality of slave station devices 200, etc. The slave station devices 200, etc. are connected to the master station device 100 and receive an uplink signal of a wireless signal from the terminal device 500.

[0042] The operation of the master station device 100 will be summarized as follows: (1) obtaining a duplexing scheme for each of a plurality of downlink signals from a base station from the configuration information or by detecting the downlink signals; (2) detecting a first timing indicative of a predetermined timing for each of the plurality of downlink signals; (3) estimating a second timing indicating a predetermined timing for each of the plurality of downlink signals based on the plurality of first timings and the acquired duplexing scheme; (4) selecting a timing reference value from the plurality of second timings; (5) adjusting each of the plurality of downlink signals based on the timing reference value and a second timing; (6) Adjust each of the corresponding uplink signals using the adjustment amounts obtained by adjusting each of the multiple downlink signals.

[0043] Furthermore, before (2), the master station device 100 may "estimate a propagation delay time between the master station device 100 and the (multiple) slave station devices for each of the multiple downlink signals," and instead of (5), "estimate a second timing indicating a predetermined timing for each of the multiple downlink signals based on the multiple first timings, the acquired duplexing method, and the multiple propagation delay times." This will be explained in detail below.

[0044] The master station device 100 includes first interfaces (antenna ports) 10-1 to 10-n for transmitting and receiving a plurality of radio signals using different duplexing methods to and from the base station.

[0045] The master station device 100 also includes an AD (Analog-to-Digital) / DA (Digital-to-Analog) conversion unit 11, a primary DL timing detection unit 13, a downlink (DL) timing adjustment unit 14, an uplink (UL) delay adjustment unit 15, a first transmission processing unit 16, a duplexing method setting unit 12-1, a secondary timing estimation unit 18, and a reference timing selection unit 17.

[0046] The first transmission processing unit 16 transmits and receives radio signals to and from the slave station devices 200 and 210 via the transmission paths 1200 and 1210 .

[0047] The duplex mode setting unit 12-1 sets information on the duplex mode of the radio signal for each of the antenna ports 10-1 to 10-n.

[0048] The AD / DA converter 11 converts the radio signals in the DL direction from the antenna ports 10-1 to 10-n into digital signals.

[0049] The primary DL timing detector 13 detects the primary DL timing (first timing) based on the information on the duplex mode set in the duplex mode setting unit 12-1. The primary DL timing refers to the timing at which a predetermined position is detected for the downlink signal of the wireless signal.

[0050] For example, the timing at which the position of the synchronization signal is detected may be set as the primary DL timing. Note that the position of the synchronization signal in LTE wireless signals is fixed, but the position of the synchronization signal in 5G wireless signals is arbitrary.

[0051] When the duplexing method is time division duplexing (TDD), the timing at which the boundary between the presence and absence of power in the DL direction is detected may be detected as the primary DL timing. Alternatively, broadcast information accompanying the synchronization signal may be obtained, a radio frame number may be obtained from the broadcast information, and the timing at which the position of the synchronization signal in the radio frame number is detected may be detected as the primary DL timing.

[0052] The secondary timing estimation unit 18 estimates the secondary DL timing (second timing) of each wireless signal based on the primary DL timing and duplex information (duplex method information) acquired by the primary DL timing detection unit 13. The secondary DL timing (hereinafter also referred to as "secondary timing") refers to the timing at which a predetermined position of a downlink signal of a wireless signal is transmitted from the master station device 100.

[0053] For example, when the primary DL timing detection unit 13 detects the timing of the primary DL based on the synchronization signal, the secondary timing estimation unit 18 may utilize the fact that the arrangement of the synchronization signal on the radio frame differs depending on the duplexing method to estimate, as the secondary timing, the transmission timing of a frame boundary between adjacent frames with different frame numbers, a subframe boundary between adjacent subframe numbers, or a slot boundary between adjacent slot numbers.

[0054] Furthermore, when the duplexing method is TDD, the secondary timing estimation unit 18 may estimate, as the secondary DL timing, the transmission timing of a boundary between adjacent frames with different frame numbers, a boundary between adjacent subframes with different subframe numbers, or a boundary between adjacent slots with different slot numbers, based on the DL / UL switching pattern boundary.

[0055] Furthermore, when the secondary timing estimator 18 has acquired the radio frame number, it may estimate the secondary DL timing based on the information on the boundary between adjacent slots with different slot numbers and the frame number.

[0056] The reference timing selector 17 compares the secondary DL timings of the radio signals estimated by the secondary timing estimator 18 and selects a reference timing (hereinafter also referred to as a "timing reference value" or "reference timing"). For example, the latest secondary timing may be selected as the reference. Alternatively, the reference timing may be selected from among the radio signals using TDD as the duplexing method.

[0057] The DL timing adjustment unit 14 adjusts the DL delay amount of each radio signal so that the difference between the reference timing selected by the reference timing selection unit 17 and the secondary DL timing becomes small.

[0058] The UL delay adjustment unit 15 adjusts the delay amount in the UL direction of the corresponding radio signal to be the same as the delay amount adjusted for each radio signal by the DL timing adjustment unit 14 .

[0059] It should be noted that a plurality of radio signals transmitted from the master station device 100 to the slave station devices 200 and 210 using the same transmission path do not have a difference in propagation delay time between the radio signals.

[0060] FIG. 4 is a flowchart showing the processing of the master station device 100 of the first embodiment. In S10, the primary DL timing detection unit 13 acquires information on the duplex mode for each wireless signal based on the setting information from the duplex mode setting unit 12-1.

[0061] In S11, the primary DL timing detector 13 detects the primary DL timing for each wireless signal based on the duplexing method.

[0062] In S12, the secondary timing estimator 18 estimates the secondary DL timing from the primary DL timing detected for each wireless signal.

[0063] In S13, the reference timing selection unit 17 compares the secondary DL timings of the radio signals estimated by the secondary timing estimation unit 18, and selects a timing to be used as a reference.

[0064] In S14, the DL timing adjustment unit 14 calculates the difference between the reference timing and the secondary timing of each radio signal.

[0065] In S15, the DL timing adjustment unit 14 adjusts the DL delay amount of each radio signal so as to minimize the difference between the reference timing and the secondary DL timing of the other radio signals.

[0066] In S16, the UL delay adjustment unit 15 inserts the same delay amount as the delay amount adjusted in the DL direction for each radio signal into the UL side of the corresponding radio signal.

[0067] As described above, according to this embodiment, the above mechanism can reduce the propagation delay time difference between the base station and the terminal device 500 more than in the case of the conventional technology. Specifically, regardless of the duplexing method, even if there is a propagation delay time difference between the base station and the master station device 100, the propagation delay time difference between the DL and UL radio signals between the base station and the slave station device 200 can be reduced or made zero.

[0068] (Modification 1 of the first embodiment) Fig. 5 is a schematic configuration diagram of a master station device 100 according to a first modification of the first embodiment. Compared to Fig. 3, a duplex mode detection unit 12-2 is provided instead of the duplex mode setting unit 12-1. That is, instead of setting a duplex mode for each wireless signal externally, the duplex mode is detected from the DL wireless signal.

[0069] When detecting the duplexing method, for example, a synchronization signal may be detected from a DL wireless signal and broadcast information may be acquired to detect the duplexing method. Alternatively, by utilizing the fact that a duplexing method is defined for each frequency band, the duplexing method may be detected based on the frequency at which the synchronization signal is detected.

[0070] The duplex mode information for each wireless signal detected by the duplex mode detection unit 12-2 is notified to the primary DL timing detection unit 13 and the secondary timing estimation unit 18. The secondary timing estimation unit 18 estimates the secondary DL timing of each wireless signal based on the duplex mode information from the duplex mode detection unit 12-2 and the primary DL timing information from the primary DL timing detection unit 13. The operation after estimation is the same as in the first embodiment.

[0071] (Modification 2 of the first embodiment) 6 is a schematic configuration diagram of a master station device 100-2 according to Modification 2 of the first embodiment. Here, the master station device 100-2 is connected via an RFU 400 to a base station 610 (640) in an equipment installation area 2200 different from its own equipment installation area 1100 (FIG. 1).

[0072] The master station device 100-2 includes third interfaces 30-1 to 30-m and third transmission processing units 31-1 to 31-m that connect to the RFUs 400, and is connected via a transmission path 3200 to the RFUs 400 in the equipment installation areas 2200-1 to 2200-m.

[0073] 7 is a schematic configuration diagram of an RFU 400 according to the second modification of the first embodiment. The RFU 400 includes first interfaces (antenna ports) 10-1 to 10-m for transmitting and receiving radio signals to and from the base station 610 and the base station system 720, an AD / DA conversion unit 11, and a fourth transmission processing unit 32. The components other than the fourth transmission processing unit 32 are the same as those in FIG.

[0074] Due to a difference in propagation delay time caused by the difference in distance between the transmission path 3100 and the transmission path 3200, a difference occurs between the timing of each radio signal at the output of the AD / DA conversion unit 11 of the master station device 100-2 and the timing of each radio signal at the output of the third transmission processing units 31-1 to 31-m.

[0075] The duplexing scheme detection unit 12-2 detects the duplexing scheme of each radio signal and notifies the secondary timing estimation unit 18 of this information. The secondary timing estimation unit 18 estimates the secondary timing from the primary DL timing detected by the primary DL timing detection unit 13. Then, the reference timing selection unit 17 selects the secondary timing to be used as a reference, and the DL timing adjustment unit 14 adjusts the secondary timing of each radio signal so that the difference between the reference timing and the timing is small. Then, the UL delay adjustment unit 15 inserts a delay amount on the UL side that is equivalent to the delay amount adjusted by the DL timing adjustment unit 14 of each radio signal.

[0076] This mechanism makes it possible to apply CA / DC even if the base stations 600, 610, and 640 are installed in different locations.

[0077] In this embodiment, a method for detecting the duplex mode has been described, but instead of the duplex mode detection unit 12-2, a duplex mode setting unit 12-1 as shown in FIG. 3 may be provided.

[0078] (Second embodiment) The second embodiment is based on Fig. 2. Fig. 8 is a schematic configuration diagram of a master station device 100-3 of the second embodiment.

[0079] In FIG. 2, the communication relay system 1000 provides LTE services, and by adding a new 5G NR-compatible slave station device 220 and changing the master station device 100 to master station device 100-3, it is assumed that the communication relay system 1000 provides LTE and 5G NR DC services in the service area 520.

[0080] The master station device 100-3 includes first interfaces (antenna ports) 10-1 to 10-n for transmitting and receiving a plurality of radio signals of different communication methods to and from the base stations 620 and 630.

[0081] The parent station device 100-3 includes an AD / DA conversion unit 11, a primary DL timing detection unit 13, a DL timing adjustment unit 14, a UL delay adjustment unit 15, a first transmission processing unit 16-1, a communication method setting unit 20-1, a child station transmission secondary timing estimation unit 18-2, and a reference timing selection unit 17.

[0082] The first transmission processing unit 16-1 relays radio signals to and from the slave station devices 200 and 210 via a transmission path 1210, and transmits and receives radio signals to and from the slave station device 220 via a transmission path 1220. A transmission delay estimator 23 included in the first transmission processing unit 16-1 estimates a transmission delay time to the slave station devices 200 and 220.

[0083] Here, the slave station devices 200 and 210 support a first communication method (for example, LTE), and the slave station device 220 supports a second communication method (for example, 5G NR).

[0084] The communication method setting unit 20-1 sets information on the communication method (LTE, 5G NR) of the wireless signal for each of the antenna ports 10-1 to 10-n. In addition to the communication method, a duplex method may also be set.

[0085] The AD / DA converter 11 converts the radio signals in the DL direction from the antenna ports 10-1 to 10-n into digital signals.

[0086] The primary DL timing detection unit 13 detects the primary DL timing based on information about the communication method set in the communication method setting unit 20-1. For example, the timing at which the position of a synchronization signal is detected may be the primary DL timing. When a synchronization signal is used, since the sequences and arrangements used for the synchronization signal differ between LTE and 5G NR, an appropriate synchronization signal detection method is selected and detected based on the information set in the communication method setting unit 20-1.

[0087] In the case of TDD, the timing at which the boundary between the presence and absence of power in the DL direction is detected may be determined as the primary DL timing. Alternatively, the timing at which the position of the synchronization signal for the radio frame number is detected may be determined by acquiring broadcast information from the synchronization signal.

[0088] The slave station transmission secondary timing estimation unit 18-2 estimates the slave station transmission secondary timing, which is the timing at which the downlink signal of the wireless signal is output from the slave station devices 200 and 220 at predetermined positions, based on the primary DL timing acquired by the primary DL timing detection unit 13 and the propagation delay to the slave station devices 200 and 220 estimated by the transmission delay estimation unit 23.

[0089] For example, when the primary DL timing detection unit 13 detects the primary DL timing based on the synchronization signal, the slave station transmission secondary timing estimation unit 18-2 may take advantage of the fact that the arrangement of the synchronization signal on the radio frame differs depending on the communication method, and estimate the slave station transmission secondary timing of the downlink signal of the radio signal based on the propagation delay to the slave station devices 200 and 220 estimated by the transmission delay estimation unit 23, such as the boundary between adjacent frames with different frame numbers, the boundary between adjacent subframes with different subframe numbers, or the boundary between adjacent slots with different slot numbers.

[0090] Furthermore, for example, when the radio frame number has been acquired, the secondary slave station transmission timing estimation unit 18-2 may estimate the secondary slave station transmission timing of the downlink signal of the radio signal based on the frame number information, the boundary between adjacent slots having different slot numbers, and the propagation delay to the slave station devices 200 and 220 estimated by the transmission delay estimation unit 23.

[0091] The reference timing selector 17 selects a radio signal to be used as a reference timing from the secondary slave station transmission timings of the radio signals estimated by the secondary slave station transmission timing estimator 18-2. For example, the radio signal with the latest timing may be selected.

[0092] The DL timing adjustment unit 14 adjusts the DL delay amount of each radio signal so that the difference between the reference timing selected by the reference timing selection unit 17 and each secondary transmission timing of each slave station becomes small.

[0093] The UL delay adjustment unit 15 inserts the same delay amount as the delay amount adjusted in the DL direction for each radio signal by the DL timing adjustment unit 14 into the UL side of the radio signal.

[0094] FIG. 9 is a flowchart showing the processing of the master station device 100-3 of the second embodiment. In S20, the primary DL timing detection unit 13 acquires information on the communication method for each wireless signal.

[0095] In S21, the primary DL timing detector 13 detects the primary DL timing for each wireless signal based on the communication method.

[0096] In S22, the transmission delay estimator 23 estimates the transmission delay time to the slave station devices 200 and 220.

[0097] In S23, the slave station transmission secondary timing estimation unit 18-2 estimates the slave station transmission secondary timing for the downlink signal of the wireless signal based on the primary DL timing detected in S21 and the propagation delay time to the slave station devices 200 and 220 estimated in S22.

[0098] In S24, the reference timing selection unit 17 selects a radio signal to be used as the reference timing from the secondary transmission timings of the radio signals to the slave stations estimated in S23.

[0099] In S25, the DL timing adjustment unit 14 adjusts the DL delay amount of each wireless signal so that the difference between the reference timing selected in S24 and each slave station transmission secondary timing becomes small (for example, minimized).

[0100] In S26, the UL delay adjustment unit 15 inserts the same delay amount as the delay amount adjusted in the DL direction for each radio signal in S25 into the UL side of the radio signal.

[0101] This mechanism makes it possible to reduce the difference in transmission timing between radio signals at the slave station devices 200, 220 regardless of the communication method, and therefore reduces or eliminates the difference in DL and UL propagation delay time between radio signals between the base stations 620, 630 and the slave station devices 200, 220.

[0102] (Modification 1 of the second embodiment) Fig. 10 is a schematic configuration diagram of a master station device 100-3 according to a first modification of the second embodiment. Compared to Fig. 8, a communication method detection unit 20-2 is provided instead of the communication method setting unit 20-1. In other words, instead of setting the communication method for each wireless signal externally, the communication method is detected from the DL wireless signal.

[0103] When detecting the communication method, for example, the communication method may be detected by comparing whether or not a synchronization signal is detected using a detection function for each communication method.Alternatively, since a communication method is defined for each frequency band, the communication method may be detected based on information about the frequency band used by the wireless signal.

[0104] The communication method information for each wireless signal detected by the communication method detection unit 20-2 is notified to the primary DL timing detection unit 13 and the slave station transmission secondary timing estimation unit 18-2. The primary DL timing detection unit 13 detects the primary DL timing based on the communication method information from the communication method detection unit 20-2.

[0105] The slave station transmission secondary timing estimator 18-2 estimates the slave station transmission secondary timing of each wireless signal in the slave station devices 200 and 220 based on the communication method information from the communication method detector 20-2, the primary DL timing information from the primary DL timing detector 13, and the propagation delay estimates between the master station device 100-3 and the slave station devices 200 and 220 by the transmission delay estimator 23. The operation after the estimation is the same as in the second embodiment.

[0106] (Modification 2 of the second embodiment) 11 is a schematic configuration diagram of a master station device 100-4 according to Modification 2 of the second embodiment. The master station device 100-4 is adapted for connection using an RFU 400 to a base station 610 (640) in an equipment installation area 2200 different from its own equipment installation area 1100 (FIG. 1).

[0107] The master station device 100-4 includes third interfaces 30-1 to 30-m and third transmission processing units 31-1 to 31-m, and is connected via a transmission path 3200 to the RFUs 400 in the equipment installation areas 2200-1 to 2200-m.

[0108] An example of the RFU 400 connected to the transmission path 3200 is the same as that shown in FIG. 7. The difference from the second modification of the first embodiment (FIG. 6) is that the communication methods of the connected base stations 600, 610, and 640 are different. In FIG. 1, for example, the base station 600 and the base station system 710 are of the LTE method, and the base station 610 and the base station system 720 are of the 5G NR method, or vice versa. Furthermore, the communication methods of base stations in the same equipment installation area may be different.

[0109] Due to a difference in propagation delay time caused by the difference in distance between the transmission path 3100 and the transmission path 3200, a difference occurs between the timing of each radio signal at the output of the AD / DA conversion unit 11 of the master station device 100-4 and the timing of each radio signal at the output of the third transmission processing units 31-1 to 31-m.

[0110] The communication method detection unit 20-2 detects the communication method of each wireless signal and notifies the primary DL timing detection unit 13 of this information. The primary DL timing detection unit 13 detects the primary DL timing in accordance with the communication method information, and the slave station transmission secondary timing estimation unit 18-2 estimates the slave station transmission secondary timing of each wireless signal in the slave station devices 200 and 220 based on the primary DL timing and the propagation delay time to the slave station devices 200 and 220.

[0111] The reference timing selector 17 selects a reference timing from the secondary transmission timing of each wireless signal estimated by the secondary transmission timing estimator 18-2. The DL timing adjuster 14 adjusts the secondary transmission timing of each wireless signal to reduce the difference between the reference timing and the secondary transmission timing of each wireless signal. The UL delay adjuster 15 inserts a delay amount on the UL side that is equivalent to the delay amount adjusted in the DL timing adjustment of each wireless signal.

[0112] This mechanism makes it possible to apply CA / DC even if the base stations 600, 610, and 640 are installed in different locations.

[0113] In this embodiment, a method for detecting a communication method has been described, but instead of the communication method detection unit 20-2, a duplex method setting unit 12-1 as shown in FIG. 3 may be provided.

[0114] Furthermore, methods for measuring the propagation delay time of a transmission path are known, and for example, a mechanism such as PTP (Precision Time Protocol) may be used.

[0115] Furthermore, even when a relay device is provided as in the slave station device 210 of FIG. 1, a transmission delay estimation unit can be provided in the slave station device 210 to measure the propagation delay time of the transmission path to the downstream slave station device 200 and transmit this to the master station device 100, thereby making it possible to estimate the propagation delay time between the master station device 100 and the slave station device 200.

[0116] Although the duplex mode and the communication mode have been described as separate embodiments, it is possible to support both. For example, this is possible by adding a duplex mode setting unit 12-1 (FIG. 3) and a duplex mode detection unit 12-2 (FIG. 5) to the second embodiment, the first modification of the second embodiment, and the second modification of the second embodiment, respectively.

[0117] (Third embodiment) The outline and details of the third embodiment will be described below. Fig. 12 is a diagram showing the outline configuration of a master station device 100-5 of the third embodiment.

[0118] (overview) When the physical layer function of the base station is separated into a first functional device and a second functional device, the first functional device is installed in an equipment installation area where the master station device is located, and the second functional device is installed outside the equipment installation area, The master station device 100-5 a master date and time corresponding to the first functional device; corresponding to the second functional device, and managing an offset master date and time to which an offset is added in order to synchronize with the master date and time; For a downlink signal corresponding to the first functional device, adjusting the timing reference value, the second timing, and the master time and date; For the downlink signal corresponding to the second functional device, the timing reference value, the second timing, and the offset master time are used for adjustment.

[0119] (detail) The master station device 100-5 is an example in which the physical layer function of a base station (for example, the base station 600 in FIG. 1) is separated, and the lower function of the physical layer (lower function: first functional device) is incorporated into the communication relay system 1000. For example, the function of an O-RU (O-RAN Radio Unit) of the O-RAN (Open Radio Access Network) Alliance may be made part of the communication relay system 1000, and connected to an O-DU (O-RAN Distributed Unit), which is the upper function of the physical layer of the base station (upper function: second functional device).

[0120] In this embodiment, the buffer capacity of the DL timing adjustment unit 14 is reduced by distributing the load of timing adjustment using the time synchronization function in the separation function of the base station.

[0121] The master station device 100-5 includes a master date and time generation unit 51. The second interfaces 40-1 to 40-m are interfaces with higher-level functions of the physical layer of a base station (not shown). The second transmission processing units 41-1 to 41-m execute processing related to transmission path frames and lower-level functions of the physical layer of the base station.

[0122] The timing management units 42-1 to 42-m manage and adjust the transmission and reception timing of radio signals, and notify timing information to a higher-level function of the physical layer of the opposing base station (not shown).

[0123] The configuration information storage units 43-1 to 43-m notify the settings of the communication method, duplex method, etc. received from the upper function of the physical layer of the opposing base station (not shown), and information for setting various information in the second transmission processing units 41-1 to 41-m to the upper function of the physical layer of the opposing base station (not shown).

[0124] The offset master date and time generating units 44-1 to 44-m have a function of synchronizing with the master date and time generated by the master date and time generating unit 51 and of being able to set an offset of the date and time.

[0125] 13 is a flowchart showing the processing of the master station device 100-5 of the third embodiment. The operation will be described with reference to FIGS.

[0126] In S400, the duplex mode detection unit 12-2 acquires (detects) the duplex mode of each wireless signal belonging to the first interfaces 10-1 to 10-n.

[0127] In S401, the primary DL timing detector 13 detects the primary DL timing for each wireless signal based on the duplexing method, and the secondary timing estimator 18 estimates the secondary timing.

[0128] In S402, the reference timing selector 17 selects a reference timing from the secondary timing estimates.

[0129] In S403, the master station device 100-5 determines whether the wireless signal belongs to one of the first interfaces 10-1 to 10-n, and if Yes, the process proceeds to S404, and if No, the process proceeds to S406.

[0130] In S404, the DL timing adjustment unit 14 adjusts the DL timing of each radio signal so that the difference between the reference timing and the secondary timing of the other radio signals is minimized.

[0131] In S405, the UL delay adjustment unit 15 inserts a delay amount equivalent to the delay amount adjusted in S404 into the UL side of the corresponding radio signal. S404 and S405 are the same as the operations in the first embodiment (S15 and S16 in FIG. 4).

[0132] In S406, the master date / time generation unit 51 synchronizes with the reference timing selected in S402. The reference timing may be any of a frame boundary, subframe boundary, or slot boundary estimated by the secondary timing estimation unit 18. Synchronization may also be based on a self-held reference date / time (not shown) and the difference between the reference date / time and the frame boundary, subframe boundary, or slot boundary. Alternatively, synchronization may be performed by calculating UTC (Coordinated Universal Time) time based on frame number information.

[0133] In S407, the offset master date and time generation units 44-1 to 44-m synchronize with the master date and time of the master date and time generation unit 51.

[0134] In S408, the second transmission processing units 41-1 to 41-m use the offset master time and date of the offset master time and date generation units 44-1 to 44-m to synchronize the time and date with a higher layer of the physical layer of the base station (not shown). For example, the synchronization method may be time synchronization using PTP, with the offset master time and date generation units 44-1 to 44-m as a boundary clock (BC) and the higher layer of the physical layer of the base station (not shown) as a slave clock. After the time synchronization is established, the master station device 100-5 re-establishes a connection between the higher layer of the physical layer of the base station (not shown) and the second transmission processing units 41-1 to 41-m.

[0135] In S409, second transmission processing units 41-1 to 41-m acquire from secondary timing estimation unit 18 the secondary timing of the radio signal belonging to second transmission processing units 41-1 to 41-m.

[0136] In S410, the second transmission processing units 41-1 to 41-m calculate the difference between the secondary timing acquired in S409 and the reference timing selected in S402, add this difference to the offset master date and time, and update the offset master date and time generation units 44-1 to 44-m.

[0137] In S411, the second transmission processing units 41-1 to 41-m use the offset master date and time generated by the offset master date and time generation units 44-1 to 44-m updated in S410 to resynchronize the date and time with the upper layer of the physical layer of the base station (not shown).

[0138] Due to this mechanism, the upper function side of the physical layer of the base station (not shown) is synchronized with the reference timing selected in S402. As a result, the secondary timing of the radio signals belonging to the second transmission processing units 41-1 to 41-m on the lower function side of the physical layer of the base station can be synchronized with the reference timing selected in S402.

[0139] Furthermore, the secondary timing of the wireless signals belonging to the first interfaces 10-1 to 10-n can also be synchronized with the reference timing selected in S402.

[0140] With the above-described mechanism, the master station device 100-5, which includes the lower functions of the base station's physical layer, can adjust the timing of each radio signal, making it possible to apply CA and DC to the communication relay system 1000. In this embodiment, in synchronizing the date and time between the upper phase side function of the base station's physical layer (not shown) and the lower functions of the base station's physical layer, which are composed of the second interfaces 40-1 to 40-m and the second transmission processing units 41-1 to 41-m, the lower functions are synchronized as a master, thereby adjusting the timing. Therefore, the lower functions do not need to have a new function for adjusting delays.

[0141] Although the above description has been given with reference to an example in which a duplex mode is detected, the present invention is not limited to this. The duplex mode may be set externally, or the communication mode may be detected and set. Alternatively, a method of matching the transmission timings of the slave station devices may be applied.

[0142] (Fourth embodiment) The outline and details of the fourth embodiment will be described below. Fig. 14 is a diagram showing the outline configuration of a master station device 100-6 of the fourth embodiment. (overview) When the physical layer function of the base station is separated into a first functional device and a second functional device, the first functional device is installed in an equipment installation area where the master station device is located, and the second functional device is installed outside the equipment installation area, The master station device 100-6 For the downlink signal corresponding to the second functional device, the difference between the timing reference value and the second timing and the difference between the difference and the predetermined delay adjustment tolerance are compared, and adjustment is made based on the comparison result.

[0143] (detail) 14 shows an example in which the physical layer function of a base station is separated and the lower function of the physical layer is incorporated into the communication relay system 1000. For example, the O-RAN Alliance O-RU function (first functional device) may be made part of the communication relay system 1000 and connected to the O-DU, which is the upper function of the physical layer of the base station (second functional device).

[0144] In this embodiment, the buffer capacity of the DL timing adjustment unit 14 is reduced by distributing the load of timing adjustment using the timing management function in the separation function of the base station.

[0145] In the third embodiment, the date and time on the lower function side of the physical layer of the base station is set as the master date and time, and the date and time on the upper function side of the physical layer of the base station is set as the slave date and time. Normally, the date and time on the upper function side of the physical layer of the base station is used as the master. In this embodiment, the date and time on the upper function side of the physical layer of the base station is used as the master.

[0146] In the parent station device 100-6, the second interfaces 40-1 to 40-m are interfaces with the upper functions of the physical layer of a base station (not shown), and the second transmission processing units 41-1 to 41-m execute processing related to the transmission path frame and the lower functions of the physical layer of the base station.

[0147] The timing management units 42-1 to 42-m manage and adjust the secondary timing of transmitting and receiving radio signals, and notify timing information to a higher-level function of the physical layer of the opposing base station (not shown). The configuration information storage units 43-1 to 43-m notify settings of the communication method, duplex method, etc. received from a higher-level function of the physical layer of the opposing base station (not shown), and information for setting various information in the second transmission processing units 41-1 to 41-m to a higher-level function of the physical layer of the opposing base station (not shown).

[0148] DL radio signals received by the first interfaces 10-1 to 10-n from the base station are converted from RF signals to digital signals by the AD / DA converter 11, and then the duplex system detector 12-2 detects the duplex system for each radio signal.

[0149] The duplex mode information for each wireless signal detected by the duplex mode detection unit 12-2 is notified to the primary DL timing detection unit 13 and the secondary timing estimation unit 18. The primary DL timing detection unit 13 detects the primary DL timing based on the duplex mode information from the duplex mode detection unit 12-2.

[0150] The secondary timing estimation unit 18 acquires the duplex mode information from the duplex mode detection unit 12-2, the primary DL timing information from the primary DL timing detection unit 13, the information stored in the configuration information storage units 43-1 to 43-m, and the duplex information and secondary timing information for each wireless signal from the timing management units 42-1 to 42-m, and estimates the secondary timing for all wireless signals.

[0151] Reference timing selector 17 compares the secondary timings of the radio signals estimated by secondary timing estimator 18 and selects a reference timing. For example, the latest secondary timing among the radio signals that do not belong to second interfaces 40-1 to 40-m may be selected as the reference timing. Alternatively, the latest secondary timing among the radio signals that use TDD duplexing and do not belong to second transmission processing units 41-1 to 41-m may be selected as the reference timing.

[0152] In the case of a radio signal belonging to the first interfaces 10-1 to 10-n, the DL delay calculation unit 50 notifies the DL timing adjustment unit 14 of the secondary timing estimate obtained by the secondary timing estimator 18 as is. In addition, in the case of a radio signal belonging to the second interfaces 40-1 to 40-m, the DL delay calculation unit 50 performs the following calculation.

[0153] If the difference between the secondary timing and the reference timing of each radio signal is within the management tolerance of the timing management units 42-1 to 42-m, the secondary timing estimate value for the corresponding radio signal within the management tolerance range is replaced with the reference timing, and notified to the DL timing adjustment unit 14, and the value of the difference between the secondary timing estimate value for the corresponding radio signal and the reference timing is notified to the timing management units 42-1 to 42-m.

[0154] Furthermore, if the difference between the secondary timing and the reference timing of each radio signal is outside the management tolerance range of the timing management units 42-1 to 42-m, the value obtained by subtracting the management tolerance value from the difference between the secondary timing and the reference timing of the radio signal in question is notified to the DL timing adjustment unit 14, and the value obtained by subtracting the value notified to the DL timing adjustment unit 14 from the difference between the secondary timing and the reference timing of the radio signal in question is notified to the timing management unit 42.

[0155] The DL timing adjustment unit 14 adjusts the DL delay amount of each radio signal so as to reduce the difference between the reference timing and the secondary timing. The UL delay adjustment unit 15 acquires the delay amount adjusted by the DL timing adjustment unit 14 for each radio signal, and adjusts the delay amount in the UL direction to be equivalent to the DL delay amount.

[0156] The timing management units 42-1 to 42-m change the transmission and reception timings of the second transmission processing units 41-1 to 41-m in cooperation with a higher function of the physical layer of the opposing base station based on the timing difference from the DL delay calculation unit 50. Note that the timing management units 42-1 to 42-m may notify the higher layer of the physical layer of the opposing base station of the timing difference from the DL delay calculation unit 50 to adjust the transmission timing from the higher layer of the physical layer of the opposing base station.

[0157] FIG. 15 is a flowchart showing the processing of the master station device 100-6 in the fourth embodiment. In S300, the master station device 100-6 acquires information on the duplex mode for each wireless signal from the duplex mode detection unit 12-2 and the configuration information storage units 43-1 to 43-m.

[0158] In S301, for radio signals belonging to the first interfaces 10-1 to 10-n, the primary DL timing detection unit 13 detects the primary DL timing for each radio signal based on the duplexing method, and the secondary timing estimation unit 18 estimates the secondary timing for each radio signal.

[0159] In addition, in S301, for radio signals belonging to the second interfaces 40-1 to 40-m, the master station device 100-6 acquires the secondary timing for each radio signal from the timing management units 42-1 to 42-m.

[0160] In S302, the reference timing selection unit 17 selects a reference timing from the secondary timing.

[0161] In S303, the master station device 100-6 determines whether the wireless signal belongs to the second interface 40-1 to 40-m, i.e., whether it is a wireless signal belonging to a lower function of the base station's physical layer, or whether it is something else. If the answer is Yes, proceed to S304; if the answer is No, proceed to S308.

[0162] In S304, the secondary timing estimator 18 calculates the difference between the secondary timing and the reference timing of each radio signal.

[0163] In S305, the master station device 100-6 determines whether the timing difference is within the tolerance of the timing management units 42-1 to 42-m, and if Yes, proceeds to S306, and if No, proceeds to S307.

[0164] In S306, the master station device 100-6 notifies the DL timing adjustment unit 14 of the secondary timing of the radio signal, the timing difference of which is within the allowable range, as the reference timing. The master station device 100-6 also notifies the timing management units 42-1 to 42-m of the timing difference. After S306, the process proceeds in parallel to S309 and S310.

[0165] In S307, if the timing difference is outside the allowable range, the master station device 100-6 subtracts the allowable management value of the timing management units 42-1 to 42-m from the timing difference and notifies the DL timing adjustment unit 14. The master station device 100-6 also notifies the timing management units 42-1 to 42-m of the timing difference minus the value notified to the DL timing adjustment unit 14. After S307, the process proceeds to S309 and S310 in parallel.

[0166] In S309, the timing management units 42-1 to 42-m adjust the transmission and reception timing between the upper function of the physical layer of the opposite base station (not shown) and the lower function of the physical layer of the base station in the master station device 100-6, based on the timing difference notified to the timing management units 42-1 to 42-m.

[0167] In S308, the master station device 100-6 notifies the DL timing adjustment unit 14 of the reference timing and the secondary timing estimate of the radio signals belonging to the second interfaces 40-1 to 40-m.

[0168] In S310, the DL timing adjustment unit 14 adjusts the DL timing of each wireless signal so that the difference between the reference timing and the notified secondary timing of the other wireless signal is minimized.

[0169] In S311, the UL delay adjustment unit 15 inserts the same delay amount as the delay amount adjusted in the DL direction of each radio signal into the UL side of the corresponding radio signal.

[0170] With the above-described mechanism, the master station device 100-6 can adjust the timing of each radio signal based on the lower-level functions of the base station's physical layer, while keeping the date and time of the upper-level functions of the base station as the master, making it possible to apply CA and DC to the communication relay system 1000.

[0171] Although the above description has been given with reference to an example in which a duplex method is detected, the present invention is not limited to this. The duplex method may be set externally, or the communication method may be detected and set. Alternatively, a method of matching the transmission timings of the slave station devices may be applied.

[0172] (Fifth embodiment) Reducing the propagation delay time within the communication relay system 1000 as much as possible is important in terms of service quality in the service area 510. In view of this, the reference timing selector 17 selects the radio signal with the latest timing to prevent a deterioration in service quality in the service area 510.

[0173] As a result, the propagation delay time between the base station and the slave station device increases for base stations with earlier timing. However, the difference in propagation delay time between the base station and the mobile station device can be reduced. Furthermore, since the DL timing adjustment unit 14 only needs to adjust the delay amount in the direction in which the delay increases, it is possible to reduce the amount of memory required for delay.

[0174] (Sixth embodiment) When the communication relay system 1000 is installed in an underground mall or the like, it may accommodate multiple operators. When used by multiple operators, if the duplexing method is TDD, it is necessary to synchronize the TDD DL / UL switching timing between the operators. This is because, when different operators use adjacent radio signals in the TDD duplexing method, if the TDD DL / UL switching timing does not match, they will interfere with each other and will not be able to provide services.

[0175] To prevent this, when selecting a timing reference value from multiple secondary DL timings, the master station device 100 preferentially selects the timing of a downlink signal whose duplexing method is time division duplex. For example, the reference timing selector 17 preferentially selects the timing of a radio signal whose duplexing method is TDD. Specifically, for example, the latest timing of the TDD radio signal may be selected as the reference timing.

[0176] FIG. 16 is a flowchart showing the processing of the master station device 100 of the sixth embodiment. In S100, the master station device 100-6 acquires information on the duplex mode for each wireless signal from the duplex mode detection unit 12-2 and the configuration information storage units 43-1 to 43-m. Note that the master station device 100-6 may also acquire the communication mode.

[0177] In S111, for radio signals belonging to the first interfaces 10-1 to 10-n, the primary DL timing detection unit 13 detects the primary DL timing for each radio signal based on the duplexing method, and the secondary timing estimation unit 18 estimates the secondary timing for each radio signal.

[0178] In S111, for radio signals belonging to the second interfaces 40-1 to 40-m, the master station device 100-6 acquires the secondary timing for each radio signal from the timing management units 42-1 to 42-m.

[0179] In S112, the reference timing selection unit 17 selects, as the reference timing, the secondary timing of the radio signal that uses the TDD duplex scheme and has the latest secondary timing.

[0180] In S113, the secondary timing estimator 18 estimates the difference between the radio signal of the reference timing and the secondary timing of another radio signal that uses the TDD duplex scheme.

[0181] In S114, the DL timing adjustment unit 14 determines whether the timing difference exceeds a threshold value, and if Yes, proceeds to S115, and if No, proceeds to S116.

[0182] In S115, the DL timing adjustment unit 14 excludes the wireless signal from the adjustment targets and blocks the DL wireless signal in the master station device 100 or slave station device 100. This is performed for all wireless signals whose duplex method is TDD.

[0183] In S116, the DL timing adjustment unit 14 adjusts the DL timing of each radio signal so that the timing difference between the radio signal with the reference timing and the other radio signals is minimized.

[0184] In S117, the UL delay adjusting unit 15 inserts the same delay amount as that adjusted for the DL side of each radio signal into the UL side of the corresponding radio signal.

[0185] This arrangement makes it possible to realize a communication relay system 1000 that is compatible with CA and DC while avoiding interference between TDD duplexing methods.

[0186] (Modification of the sixth embodiment) The sixth embodiment is applied to the configuration of Fig. 2, and an example is shown in which a reference timing is preferentially selected for a radio signal whose duplexing method is TDD. Specifically, this is effective when DC is applied to, for example, a case in which the communication method is LTE and the duplexing method is FDD, and a case in which the communication method is 5G NR and the duplexing method is TDD. Note that, in the following, explanations of matters similar to those already explained will be omitted as appropriate.

[0187] FIG. 17 is a flowchart showing the processing of the master station device 100-6 in a modified example of the sixth embodiment. In S220, the master station device 100-6 acquires information on the duplex mode and communication mode for each wireless signal.

[0188] In S221, the primary DL timing detector 13 detects the primary DL timing for each wireless signal based on the duplexing method and communication method.

[0189] In S222, the master station device 100-6 estimates the propagation delay time between itself and each slave station device.

[0190] In S223, the secondary timing estimator 18 estimates the secondary slave station transmission timing for each wireless signal of each slave station device based on the secondary timing estimate value and the propagation delay time estimated in S222.

[0191] In S224, the reference timing selection unit 17 selects, as the reference timing, the secondary slave station transmission timing of the wireless signal that uses TDD duplexing and has the latest secondary slave station transmission timing from among the wireless signals of the slave station devices.

[0192] In S225, the secondary timing estimation unit 18 estimates the difference between the reference timing and the secondary timing of transmission from the slave station of another wireless signal that uses the TDD duplex scheme.

[0193] In S226, the DL timing adjustment unit 14 determines whether the timing difference exceeds a threshold value. If Yes, proceed to S227; if No, proceed to S228.

[0194] In S227, the DL timing adjustment unit 14 excludes the wireless signal from the adjustment targets and blocks the DL signal in the master station device 100-6 or the slave station device. This is performed for all wireless signals whose duplex method is TDD.

[0195] In S228, the DL timing adjustment unit 14 adjusts the DL timing of each radio signal so that the difference between the radio signal of the reference timing and the slave station transmission timing of the other radio signals using the TDD duplex method is minimized.

[0196] In S229, the UL delay adjusting unit 15 inserts the same delay amount as that adjusted for the DL side of each radio signal into the UL side of the corresponding radio signal.

[0197] Because of this mechanism, in a communication relay system using two communication methods, such as the service area 520 in FIG. 2, even if there is a difference in propagation delay time between the master station device 100 and the slave station device for each communication method, it is possible to realize a communication relay system 1000 that is compatible with CA and DC while avoiding interference between TDD duplex methods.

[0198] (Seventh embodiment) There may be cases where it is not necessary to provide CA or DC for some of the wireless signals. For example, there may be some operators that want to provide CA or DC and others that do not. In such cases, there is no need to synchronize the timing of wireless signals that do not provide CA or DC.

[0199] Regarding timing adjustment, if the size of the service area provided by the slave station device of the communication relay system 1000 is small, the propagation delay time difference within the service area is small, and so as long as the propagation delay time difference in the communication relay system 1000 is within an allowable range, there is no need to match the timing difference within the communication relay system 1000. By providing an allowable range for the timing difference, the buffer capacity of the DL timing adjustment unit 14 and the UL delay adjustment unit 15 can be reduced.

[0200] For this reason, the selection method is determined by setting a policy to provide flexibility in the selection of the reference timing selector 17. In other words, when the master station device 100 selects a timing reference value from multiple secondary DL timings, it selects the timing based on the set policy. For example, the policy may describe radio signals to be adjusted and radio signals that are not to be adjusted, and the non-target radio signals may be excluded from the selection.

[0201] Furthermore, taking into consideration the range of the service area, a margin may be provided in the adjustment range, and the reference value may be selected so that the timing difference between each wireless signal falls within the margin. For example, if the timing of a wireless signal that is close to the median value of the timing of each wireless signal is used as the reference, and the timing difference between this wireless signal and other wireless signals is within the margin, that wireless signal may be selected as the timing reference.

[0202] Alternatively, the parameter may be the delay amount for each wireless signal, and the objective function may be an optimization method for reducing the difference in secondary transmission timing for each wireless signal in each slave station device, to select a reference wireless signal.

[0203] By doing so, it is possible to reduce the buffer used for delay time adjustment by the timing adjustment margin.

[0204] The parent station device 100 of this embodiment is equipped with a control device such as a CPU, a storage device such as a ROM (Read Only Memory) or RAM, and an external storage device such as an HDD or CD drive, and has a hardware configuration that utilizes a normal computer.

[0205] The programs executed by the master station device 100 and the RFU 400 of this embodiment are provided as files in an installable or executable format recorded on a computer-readable recording medium such as a CD-ROM, DVD, or USB memory.

[0206] The program may also be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network, or to be provided or distributed via a network such as the Internet, or to be provided by being pre-installed in a ROM or the like.

[0207] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0208] 11...AD / DA conversion unit, 12-1...duplexing method setting unit, 12-2...duplexing method detection unit, 13...primary DL timing detection unit, 14...DL timing adjustment unit, 15...UL delay adjustment unit, 16...first transmission processing unit, 17...reference timing selection unit, 18...secondary timing estimation unit, 100...master station device, 200, 210, 220...slave station devices, ..., 500...terminal device, 600, 610, 620, 630, 640...base station, 710, 720...base station system, 1000...communication relay system

Claims

1. A communication relay system that relays communication between a base station and a wireless communication terminal, a master station device that receives a downlink signal of a radio signal from the base station; a plurality of slave station devices connected to the master station device and receiving an uplink signal of a wireless signal from the wireless communication terminal device; The master station device Obtaining a duplex mode for each of the plurality of downlink signals from the base station from configuration information or by detecting the downlink signals; Detecting a first timing indicative of a predetermined timing for each of the plurality of downlink signals; estimating a second timing indicating a predetermined timing for each of the plurality of downlink signals based on the plurality of first timings and the acquired duplex scheme; selecting a timing reference value from the plurality of second timings; adjusting each of the plurality of downlink signals based on the timing reference value and the second timing; A communication relay system that adjusts each of the uplink signals using an adjustment amount obtained by adjusting each of the downlink signals.

2. A communication relay system that relays communication between a base station and a wireless communication terminal, a master station device that receives a downlink signal of a radio signal from the base station; a plurality of slave station devices connected to the master station device and receiving an uplink signal of a wireless signal from the wireless communication terminal device; The master station device Obtaining a duplex mode for each of the plurality of downlink signals from the base station from configuration information or by detecting the downlink signals; Estimating a propagation delay time between the master station device and the slave station device for each of the plurality of downlink signals; Detecting a first timing indicative of a predetermined timing for each of the plurality of downlink signals; estimating a second timing indicating a predetermined timing for each of the plurality of downlink signals based on the plurality of first timings, the acquired duplexing scheme, and the plurality of propagation delay times; selecting a timing reference value from the plurality of second timings; adjusting each of the plurality of downlink signals based on the timing reference value and the second timing; A communication relay system that adjusts each of the uplink signals using an adjustment amount obtained by adjusting each of the downlink signals.

3. When a physical layer function of the base station is separated into a first functional device and a second functional device, the first functional device is installed in an equipment installation area where the master station device is located, and the second functional device is installed outside the equipment installation area, The master station device a master time corresponding to the first functional device; managing an offset master date and time that corresponds to the second functional device and that is obtained by adding an offset to the master date and time in order to synchronize with the master date and time; For the downlink signal corresponding to the first functional device, adjusting using the timing reference value, the second timing, and the master time and date; 2. The communication relay system according to claim 1, wherein the downlink signal corresponding to the second functional device is adjusted using the timing reference value, the second timing, and the offset master date and time.

4. When a physical layer function of the base station is separated into a first functional device and a second functional device, the first functional device is installed in an equipment installation area where the master station device is located, and the second functional device is installed outside the equipment installation area, The master station device 2. The communication relay system according to claim 1, wherein, for the downlink signal corresponding to the second functional device, a difference between the timing reference value and the second timing and a predetermined delay adjustment tolerance is compared, and adjustment is made based on the comparison result.

5. The master station device 5. The communication relay system according to claim 1, wherein when the timing reference value is selected from a plurality of the second timings, the timing of the downlink signal having the latest timing is selected.

6. The master station device 5. The communication relay system according to claim 1, wherein when selecting the timing reference value from a plurality of the second timings, the timing of the downlink signal whose duplexing method is time division duplex is selected with priority.

7. The master station device 5. The communication relay system according to claim 1, wherein when the timing reference value is selected from a plurality of the second timings, the timing is selected based on a set policy.

8. A communication relay method by a communication relay system that relays communication between a base station and a wireless communication terminal, comprising: The communication relay system includes: a master station device that receives a downlink signal of a radio signal from the base station; a plurality of slave station devices connected to the master station device and receiving an uplink signal of a wireless signal from the wireless communication terminal, The master station device Obtaining a duplex mode for each of the plurality of downlink signals from the base station from configuration information or by detecting the downlink signals; Detecting a first timing indicative of a predetermined timing for each of the plurality of downlink signals; estimating a second timing indicating a predetermined timing for each of the plurality of downlink signals based on the plurality of first timings and the acquired duplex scheme; selecting a timing reference value from the plurality of second timings; adjusting each of the plurality of downlink signals based on the timing reference value and the second timing; A communication relay method, comprising adjusting each of the plurality of downlink signals by an adjustment amount, and adjusting the corresponding uplink signals using the adjustment amount.

9. A communication relay system that relays communication between a base station and a wireless communication terminal, a master station device that receives a downlink signal of a radio signal from the base station; a plurality of slave station devices connected to the master station device and receiving an uplink signal of a wireless signal from the wireless communication terminal, The master station device is a computer. Obtaining a duplex mode for each of the plurality of downlink signals from the base station from configuration information or by detecting the downlink signals; Detecting a first timing indicative of a predetermined timing for each of the plurality of downlink signals; estimating a second timing indicating a predetermined timing for each of the plurality of downlink signals based on the plurality of first timings and the acquired duplexing scheme; selecting a timing reference value from the plurality of second timings; adjusting each of the plurality of downlink signals based on the timing reference value and the second timing; a program for executing a process of adjusting each of the uplink signals by using an adjustment amount obtained by adjusting each of the plurality of downlink signals;

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