Method for detecting a synchronization deviation between communication stations

Abstract

A method for detecting a synchronization deviation between communication stations, wherein the method is a method for detecting, in first and second communication stations selected from two or more communication stations connected to each other via a communication method in such a way that they can communicate with each other, a temporal deviation between a time information sent by a transmitter (X) of the first communication station (A) and received by the second communication station (B), and a time information sent by a transmitter (Y) of the second communication station (B) and received by the first communication station (A), wherein the communication stations each clock the time in a corresponding manner, and sending a predetermined blank information in a case of sending an indefinite time information,selected from a transmission time information (TXA) from the first communication station to the second communication station, a transmission time information (TYB) from the second communication station to the first communication station, a reception time (TXB) of a clock at the second communication station when transmitting from the first communication station to the second communication station, and a reception time (TYA) of a clock at the first communication station when transmitting from the second communication station to the first communication station, wherein the method, in a method which includes: , (1) a step in which the first communication station transmits TXA and TYA and records the transmission time TXA, (2) a step in which the second communication station receives TXA and TYA and measures and records the reception time TXB, (3) a step in which the second communication station transmits TXB and TYB and records the transmission time of TYB, and (4) a step in which the first communication station receives TXB and TYB and measures and records the receive time TYA for a set of input values ​​of TXA, TXB, TYA and TYB: Deriving a transmission time of a signal between the first communication station and the second communication station based on an arithmetic mean of an increase (ΔTXB-A) from TXA to TXB and an increase (ΔTYA-B) from TYB to TYA, at each station; or Determining the time difference between the first communication station and the second communication station by subtracting the increase (ΔTXB-A) from the transmission time or by subtracting the transmission time from the increase (ΔTYA-B).

Description

Technical area

[0001] The present invention relates to a method for detecting a synchronization deviation between communication stations for synchronizing the time of communication stations connected to each other via a communication method (including wired or wireless) to communicate with each other. Background technology

[0002] Methods are already known for synchronizing the time of clocks / clock generators at remote locations. For example, as described in cited publication 1 (JP 2006 292677 A), the following methods are known for accurate time transmission from clocks at remote locations: 1) Common View (transmission accuracy: several tens of nanoseconds to several nanoseconds); 2) GPS carrier wave phase (transmission accuracy: a few nanoseconds to a few hundred picoseconds); and 3) Two-way satellite time and frequency transmission (transmission accuracy: sub-nanoseconds).

[0003] However, devices for implementing these methods are not compact or lightweight enough to be carried by a normal user. Since a satellite is used, additional equipment for observing the satellite is required. Furthermore, since a spectral dispersion signal with a bandwidth of approximately several megahertz is used as a time signal, a spectral dispersion modem with a complex structure is required, and a broadband communication method of several megahertz or more is needed.

[0004] As an example where no satellite is used, as described in PTL 2 (JP 2015 152308 A), a signal is modulated using a pseudo noise signal and transmitted as a signal for synchronization, and a receiving unit obtains a demodulation signal from the received signal to obtain the timing of modulation by a correlation process.

[0005] Another well-known technique for synchronizing widely distributed clocks / clocks in a network is the standardization of a protocol based on the IEEE 1588 standard. This is used to adjust a slave clock to match the speed of a master clock. To measure communication delay in a forward path (from master to slave) and a reverse path (from slave to master), two send times and two receive times are performed end-to-end at the master and slave, respectively. A software stamp or a hardware stamp is used to record the local time at the time of reception and transmission of four messages (Sync, Followup, DelayReq, and DelayResp).

[0006] An example sequence used for this standard is shown in Fig. 16. (1) The master reads the current local system time (software timestamp Tm1 at Tm1) and transmits the time by inserting it into a sync message. This message is later transmitted by the master at Tm1', and this time serves as a hardware timestamp. This message reaches the slave at Ts1' (local slave time), and after a short delay, the slave software receives it at Ts1, reads the hardware timestamp, and accepts Ts1'.

[0007] If Tms is the time difference between the clocks of the master and the slave, Ts1' is equal to the value of (Tm1' + Tms) as long as there is no communication delay.

[0008] (a) After the sync message is transmitted, the master software reads the transmission time Tm1' of the sync message from a timestamp unit.

[0009] (b) This (Tm1') is inserted into a subsequent message transmitted at Tm2. This message is received by the slave software at Ts2. At this point, the slave software has both timing information elements Ts1' (sync reception time) and Tm1' (sync transmission time), and a path delay Tmsd between the master and slave is obtained according to Math. 1. Tmsd=(Ts1′+Tms)−Tm1′

[0010] (c) In response to the transmission of a DelayReq message from the slave, the master sends a DelayResp message. As in Fig. As shown in Figure 3, these messages can be used to calculate the delay of the communication path from the slave to the master. The slave software reads the current local system time at Ts3 and sends it by inserting it into the DelayReq message. After the message is sent, the slave software reads a timestamp, records a transmission time Ts3 of the message, and waits for a response from the master.

[0011] The DelayReq message reaches the master at Tm3 and is processed by the master software at Tm3. The software then reads the timestamp and obtains the reception time Tm3.

[0012] (d) This time value (Tm3') is inserted into the DelayResp message sent to the slave at Tm4. The slave software receives the DelayResp message at Ts4 and extracts Tm3', which is time information.

[0013] The slave calculates a communication delay Tsmd from the slave to the master according to Math. 2. Tmsd=Tm3′−(Ts3′+Tms)

[0014] Math. 1 and Math. 2 each contain the unknown variable, the time difference Tms between the master and the slave, and Tmsd, where Tsmd cannot be obtained individually. Thus, it is assumed here that the communication path is symmetrical. Tmsd=Tmsd=Td

[0015] By adding Math. 1 and Math. 2 you get the following formula.

[0016] [Math. 4] Td=12[(Ts1′−Tm1′)+(Tm3′−Ts3′)]

[0017] This calculation is performed by the slave. That is, the slave receives (A) Tm1' from the follow-up message from the master, (B) Ts1' from the reception timestamp, (C) Ts3' from the transmission timestamp, and (D) Tm3' from the DelayResp message from the master.

[0018] A communication path delay Td is obtained in the above manner, and accordingly, the time difference between the slave and the master can be calculated as follows. Tms=Td−(Ts1′−Tm1′)Tms=(Tm3′−Ts3′)−Td Citation listPatent literature PTL 1: JP 2006 292677 A PTL 2: JP 2015 152308 A Non-patent literature

[0019] NPL 1: Gerstenhaber, Michael O'Sullivan, “Device-clock Synchronization using IEEE 1588 and BLACKFIN-incorporated processor,” Analog Dialogue 43-11, November (2009), www.analog.com / jp / analogdialogue

[0020] US 7 221 686 B1 discloses a method for determining the temporal relationship and synchronization between different clocks in a communication network.

[0021] WO 2007 / 073 465 A1 discloses methods for determining propagation times between communication stations by exchanging transmission and reception times of messages between two stations. Summary of the inventionTechnical problem

[0022] According to the present invention, transmission time and reception time are transmitted between a first communication station and a second communication station that can communicate with each other, and a time deviation is calculated simultaneously in both communication stations. Additionally, a signal synchronized with a clock signal is transmitted and received between the first communication station and the second communication station, and a phase difference between a received signal and the clock signal is transmitted between them, and each phase deviation is calculated simultaneously in both communication stations.

[0023] These features are obviously different from those disclosed in the above patent literature, non-patent literature or other related art.

[0024] The calculated time deviation or phase deviation can be used to adjust the clock signal frequency within a phase range, but can also be used as a correction value. Time transmission is performed by using clocks from intermediary clocks, and a deviation in time is calculated simultaneously in both communication stations. To realize a super-distributor type clock for which a master clock is not specified regardless of the use of multiple clocks, it is desirable to use information about a clock deviation or a phase difference from the median, calculated according to a predetermined method, as a correction value, instead of locking the time or phase. Solution to the problem

[0025] A method for detecting a synchronization deviation between communication stations according to the present invention is a method for detecting, in first and second communication stations selected from two or more communication stations connected to each other via a communication method (including wired or wireless) so that they can communicate with each other, a time deviation between the time information transmitted by a transmitter (X) of the first communication station (A) and received by the second communication station (B) and time information transmitted by a transmitter (Y) of the second communication station (B) and received by the first communication station (A), wherein the communication stations each clock the time in a consistent manner, and

[0026] Sending predetermined blank information in a case of sending indefinite time information selected from transmission time information (TXA) from the first communication station to the second communication station, transmission time information (TYB) from the second communication station to the first communication station, reception time (TXB) of a clock at the second communication station when sending from the first communication station to the second communication station, and reception time (TYA) of a clock at the first communication station when sending from the second communication station to the first communication station, the method comprising a process comprising the following steps: (a1) a step in which the first communication station transmits TXA and TYA and records the transmission time TXA, (a2) a step in which the second communication station receives TXA and TYA and measures and records the reception time TXB, (a3) a step in which the second communication station transmits TXB and TYB and records the transmission time TYB, and (a4) a step in which the first communication station receives TXB and TYB and measures and records the reception time TYA for a set of input values ​​of TXA, TXB, TYA and TYB, includes: Deriving a time required for a signal to travel between the first communication station and the second communication station (hereinafter referred to as transmission or sending time) based on an arithmetic mean of an increase (ΔTXB-A) from TXA to TXB and an increase (ΔTYA-B) from TYB to TYA, at each station; or Determining the time deviation between the first communication station and the second communication station by subtracting the gain (ΔTXB-A) from the above-mentioned transmission time or by subtracting the transmission time from the gain (ΔTYA-B).

[0027] Alternatively, instead of the sequence from (a1) to (a4), the following sequence is possible: (b1) a step in which the first communication station sends a synchronization signal and records the transmission time TXA of the synchronization signal, (b2) a step in which the second communication station receives the synchronization signal and TXA and records the reception time TXB of the synchronization signal, (b3) a step in which the second communication station sends a synchronization signal and TXB and records the transmission time TYB of the synchronization signal, (b4) a step in which the first communication station receives the synchronization signal and TXB and records the reception time TYA of the synchronization signal, (b5) a step in which the first communication station sends at least TXA and TYA, (b6) a step in which the second communication station receives at least TXA and TYA, (b7) a step in which the second communication station sends at least TYB, and (b8) a step in which the first communication station receives at least TYB for a set of input values ​​of TXA, TXB, TYA and TYB,

[0028] Deriving a transmission time of a signal between the first communication station and the second communication station based on an arithmetic mean of an increase (ΔTXB-A) from TXA to TXB and an increase (ΔTYA-B) from TYB to TYA, at each station; or

[0029] Determining the time deviation between the first communication station and the second communication station by subtracting the gain (ΔTXB-A) from the transmission time or by subtracting the transmission time from the gain (ΔTYA-B).

[0030] The transmission time information (TXA) from the first communication station to the second communication station and the transmission time information (TYB) from the second communication station to the first communication station are each measured by receiving a reflection signal from a corresponding transmission end / transmission endpoint.

[0031] The transmission time information (TXA) from the first communication station to the second communication station, the transmission time information (TYB) from the second communication station to the first communication station, the reception time (TXB) of a clock at the second communication station when transmitted from the first communication station to the second communication station, and the reception time (TYA) of a clock at the first communication station when transmitted from the second communication station to the first communication station are each information in a state in which phases of the clocks A and B are synchronized.

[0032] Alternatively, the following sequence is possible instead of the sequence of (a1) to (a4). Note that the transmission time information (TXA) transmitted by the first communication station is used as a synchronization signal transmitted by the first communication station, and the transmission time information (TYB) transmitted by the second communication station is used as a synchronization signal transmitted by the second communication station.

[0033] In a method comprising (c1) a step in which the first communication station ends the scheduled transmission time TXA and records the transmission time TXA, (c2) a step in which the second communication station receives TXA and records its reception time TXB, (c3) a step in which the second communication station transmits TXB and its scheduled transmission time TYB and records the transmission time TYB of TXB, (c4) a step in which the first communication station receives TXB and TYB and records their reception time TYA, (c5) a step in which the first communication station sends at least TYA, and (c6) a step in which the second communication station receives at least TYA, for a set of input values ​​of TXA, TXB, TYA and TYB at each station, a transmission time of a signal between the first communication station and the second communication station is derived based on an arithmetic mean of an increase (ΔTXB-A) from TXA to TXB and an increase (ΔTYA-B) from TYB to TYA, or the time deviation between the first communication station and the second communication station is determined by subtracting the increase (ΔTXB-A) from the transmission time or by subtracting the transmission time from the increase (ΔTYA-B).

[0034] Alternatively, a method for detecting a synchronization deviation between communication stations according to the present invention a method for detecting, in first and second communication stations selected from two or more communication stations connected to each other via a communication method so that they can communicate with each other, a time deviation between the time information transmitted by a transmitter (X) of the first communication station (A) and received by the second communication station (B) and time information transmitted by a transmitter (Y) of the second communication station (B) and received by the first communication station (A), wherein the communication stations each clock the time in a consistent manner, wherein the second communication station receives a first communication station signal transmitted by the first communication station and synchronized with a signal from clock X of the first communication station, the first communication station receives a second communication station signal transmitted by the second communication station and synchronized with a signal from clock Y of the second communication station, the method comprising, when the first and second communication station signals have a phase difference which is converted to a predetermined common frequency: (d1) by the first communication station, transmitting the first communication station signal, receiving the transmitted first communication station signal and measuring a phase difference (Φ1XA) between the received first communication station signal and a signal from clock / clock A of the first communication station signal; (d2) by the second communication station, receiving the first communication station signal and measuring a phase difference (Φ1XB) between the received first communication station signal and a clock / clock B signal from the second communication station; (d3) by the second communication station, transmitting the second communication station signal and the phase difference (Φ1XB), receiving the transmitted second communication station signal and measuring a phase difference (Φ1YB) between the received second communication station signal and the clock / clock B signal from the second communication station; (d4) by the first communication station, receiving the second communication station signal and the phase difference (Φ1XB) and measuring a phase difference (Φ1XB) between the received second communication station signal and the signal of the first communication station; (d5) by the first communication station, transmitting the first communication station signal, the phase difference (Φ1XA) and the phase difference (Φ1YA) and receiving the transmitted first communication station signal; (d6) by the second communication station, receiving the first communication station signal, the phase difference (Φ1XA) and the phase difference (Φ1YA) and measuring a phase difference (Φ2XB) between the received signal of the first communication station and the signal of clock / clock B from the second communication station; (d7) by the second communication station, transmitting at least the phase difference (Φ1YB); (d8) by the first communication station, receiving at least the phase difference (Φ1YB); and for a phase difference ΦX obtained by subtracting the phase difference (Φ1XA) from the phase difference (Φ1XB) and a phase difference ΦY obtained by subtracting the phase difference (Φ1YB) from the phase difference (Φ1YA), deriving a phase difference due to a transmission between the first communication station and the second communication station based on an arithmetic mean of the phase differences ΦX and ΦY, and deriving a phase difference due to a time deviation at the second communication station from the time of the first communication station based on an arithmetic mean of the phase differences ΦX and -ΦY.

[0035] The phase difference (ΦXA) transmitted from the first communication station to the second communication station and the phase difference (ΦYB) transmitted from the second communication station to the first communication station are each measured by receiving a reflection signal from a corresponding transmitting end / transmitting endpoint.

[0036] When measuring phase difference, the phase difference is an unwrapped value using a predetermined time as the starting point.

[0037] Alternatively, instead of the sequence from (d1) to (d8), the following sequence is possible.

[0038] It should be noted that a clock X / clock X is a signal synchronized with the clock A or a signal generated from a partial signal of the clock A, wherein for the first communication station signal transmitted from the first communication station, a phase difference between the received first communication station signal and the clock / clock A signal of the first communication station is a predetermined phase difference (ΦA), and a clock Y is a signal synchronized with the clock B or a signal generated from a partial signal of the clock B, wherein for the clock / clock B signal of the second communication station transmitted from the second communication station, a phase difference between the received second communication station signal and the second communication station signal is a predetermined phase difference (ΦB). (e1) By the first communication station, sending the first communication station signal and the phase difference (ΦA), (e2) by the second communication station, receiving the signal of the first communication station and the phase difference (ΦA) and measuring a phase difference (Φ1XB) between the received first communication station signal and the second communication station signal, (e3) by the second communication station, transmitting the second communication station signal, the phase difference (ΦB) and the phase difference (Φ1XB), (e4) by the first communication station, receiving the second communication station signal, the phase difference (ΦB) and the phase difference (Φ1XB) and measuring a phase difference (Φ1YA) between the received second communication station signal and the first communication station signal, (e5) by the first communication station, transmitting at least the phase difference (Φ1YA), (e6) by the second communication station, receiving at least the phase difference (Φ1YA), and for a phase difference ΦX obtained by subtracting the phase difference (ΦA) from the phase difference (Φ1XB), and a phase difference ΦY obtained by subtracting the phase difference (ΦB) from the phase difference (Φ1YA), deriving a phase difference between the first communication station and the second communication station based on an arithmetic mean of ΦX and the phase difference ΦY, and deriving a phase difference due to a time deviation at the second communication station from the time of the first communication station based on an arithmetic mean of the phase differences ΦX and -ΦY.

[0039] In the first communication station or the second communication station, the received phase difference is preferably corrected using an offset phase difference generated from each receiving point to a phase difference measuring point.

[0040] The communication between the first communication station and the second communication station may be wireless communication, and the signal of the first communication station or the signal of the second communication station may be a carrier wave modulated using information including the phase difference ΦXB or ΦYA.

[0041] The wireless communication between the first communication station and the second communication station may be performed using a common frequency channel under time-sharing.

[0042] In the wireless communication between the first communication station and the second communication station, a frequency channel in downstream communication from the first communication station to the second communication station and a frequency channel in upstream communication from the second communication station to the first communication station may be different, and the downstream communication and the upstream communication may be performed in time slots that partially overlap each other.

[0043] The following may alternatively be included.

[0044] The first communication station and the second communication station each record the integrated phase of a clock signal starting from a time point converted into a predetermined time point of the first communication station or the second communication station, and a quotient modulo 2π rad of each integrated phase is used as the time, the first communication station transmits information containing the time (TXB) and the phase difference (ΦXB) of the first communication station, and the second communication station transmits information containing the time (TYA) and the phase difference (ΦYA) of the second communication station, the first communication station corrects the phase difference by a transition in stored data of a phase obtained on the basis of an arithmetic mean of the time (TXB) of the first communication station and the reception time (TYA), or corrects the time deviation at the first communication station on the basis of an arithmetic mean of the time (TXB) and the time (-TYA), and the second communication station corrects the phase difference by a transition into stored data of a phase obtained based on an arithmetic mean of the time (TYA) of the second communication station and the reception time (TXB), or corrects the time deviation at the second communication station based on an arithmetic mean of the time (TYA) and the time (-TXB).

[0045] The detection of a synchronization deviation between two or more communication stations includes categorizing the second communication station for which detection of a synchronization deviation from the predetermined first communication station has been completed into a first communication station group together with the predetermined first communication station and categorizing a communication station group for which the detection of a synchronization deviation is still to be completed into a second communication station group, and sequentially performing the detection of a synchronization deviation between communication stations for a pair of the first communication station and the second communication station according to an order, wherein the order is obtainable by a method for determining the order of detection of synchronization deviation by performing the following process until no communication station is categorized in the second communication station group, and when a communication station selected from the second communication station group, (f1) is capable of communicating with a communication station belonging to the first communication station group, the category of the selected communication station is transferred from the second communication station group to the first communication station group, or (f2) is unable to communicate with a communication station belonging to the first communication station group, a new second communication station is selected from the second communication station group, and the process returns to (1), whereby a synchronization deviation between three or more communication stations connected in series can be detected.

[0046] Detecting a synchronization discrepancy between two or more communication stations involves: categorizing a communication station determined to be capable of communicating with the predetermined first communication station into a first candidate communication station group together with the first communication station, and categorizing a communication station determined to be incapable of communicating into a second candidate communication station group, Selecting one of possible orders by a method for determining the order of a pair of communication stations to apply the method for detecting a synchronization deviation between communication stations by performing the following process until no communication station is / is categorized into the second candidate communication station, for a new communication station selected from the second candidate communication station, (g1) if communication with a communication station belonging to the first candidate communication station group is possible, the category of the selected communication station is transferred from the second candidate communication station group to the first candidate communication station group, or (g2) if communication with a communication station belonging to the first candidate communication station group is not possible, a new communication station is selected from the second candidate communication station group, and the process returns to (1), and Detecting a synchronization deviation between two or more communication stations by sequentially performing communication from the first communication station to a communication station selected as the second communication station according to the selected order, and when the order comes to an end, performing communication from the last second communication station to the first communication station in the reverse order.

[0047] Thus, the detection of a synchronization deviation from a plurality of communication stations can be performed almost simultaneously for a single communication station. That is, the communication order is first determined, and then the first communication station is set for a single synchronization deviation detection time during the process, and the second communication station is subsequently switched. By this method, the detection of a synchronization deviation between communication stations can be performed almost simultaneously among three or more communication stations connected in parallel. Advantageous effects of the invention

[0048] According to the present invention, the transmission time and reception time at a first communication station and a second communication station that can communicate with each other are transmitted between them, and a timing deviation is calculated simultaneously in both communication stations. Similarly, in addition to a signal synchronized with a clock signal, a phase difference between a received signal and the clock signal itself is transmitted between the first communication station and the second communication station, and each phase deviation can be calculated simultaneously in both communication stations. Short description of the drawings [ Fig. 1] Fig. 1 is a block diagram illustrating a device configuration example to which the present invention is applied, where (Φ) refers to a phase and (t) refers to time, being a configuration example of a wireless communication station A in which a frequency generator (1) generating a clock A oscillates autonomously. [ Fig. 2] Fig. 2 is a block diagram showing a device configuration example to which the present invention is applied, where (Φ) refers to a phase and (t) refers to time, being a configuration example of a wireless communication station B in which a frequency generator (1) generating a clock B is operated in phase synchronization with the frequency generator (1) generating the clock A in the wireless communication station A in Fig. 1 generated. [ Fig. 3] Fig. 3 is a block diagram illustrating a configuration example of the communication station A, where (Φ) refers to a phase and (t) refers to time, wherein an antenna, a receiver, and a demodulator are divided into those for receiving electromagnetic waves from a virtual reference station of the own station and those for receiving electromagnetic waves from a partner station. [ Fig. 4] Fig. 4 is a block diagram illustrating a configuration example of the communication station B, where (Φ) refers to a phase and (t) refers to time, wherein an antenna, a receiver, and a demodulator are divided into those for receiving electromagnetic waves from a virtual reference station of the own station and those for receiving electromagnetic waves from a partner station. [ Fig. 5] Fig. 5 is a block diagram showing a device configuration example of the communication station A, where (Φ) refers to a phase and (t) refers to time, where a split antenna is used as a transmitting antenna and a receiving antenna, and where the clock A is used instead of a clock X. [ Fig. 6] Fig. 6 is a block diagram showing a device configuration example of the communication station B, where (Φ) refers to a phase and (t) refers to time, using a split antenna as a transmitting antenna and a receiving antenna. [ Fig. 7] Fig. Fig. 7 is a timing chart illustrating a time sequence in which a method for detecting a synchronization deviation between communication stations according to the present invention is applied to the device configurations in Fig. 1 and Fig. 2 or Fig. 3 and Fig. 4 is applied. [ Fig. 8] Fig. Fig. 8 is a timing chart illustrating a sequence in which a method for detecting a synchronization deviation between communication stations according to the present invention is applied to the device configurations in Fig. 1 and Fig. 2 or Fig. 3 and Fig. 4 is applied, expressed as phase difference. [ Fig. 9] Fig. 9 is a timing chart illustrating a time sequence in which a method for detecting a synchronization deviation between communication stations according to the present invention is applied to the device configurations in Fig. 5 and Fig. 6 is applied. [ Fig. 10] Fig. 10 is a timing chart illustrating a sequence in which a method for detecting a synchronization deviation between communication stations according to the present invention is applied to the device configurations in Fig. 5 and Fig. 6 is applied, expressed as phase difference. [ Fig. 11] Fig. 11 is a block diagram illustrating a configuration example of the communication station A for simultaneously detecting a phase deviation and a deviation in time in a fifth embodiment. [ Fig. 12] Fig. 12 is a block diagram illustrating a configuration example of the communication station A for simultaneously detecting a phase deviation and a deviation in time using two frequencies in the fifth embodiment. [ Fig. 13] Fig. 13 is a timing chart for simultaneously detecting a phase deviation and a deviation in time using the device configuration in Fig. 11 or Fig. 12. [ Fig. 14] Fig. 14 is a block diagram of communication station A in a sixth embodiment. In this configuration, clock X is the same as clock A, a split antenna is used as a transmitting antenna and a receiving antenna, and an input of a reflected wave from the antenna to a receiver and demodulator is used to obtain a time stamp at the time of transmission from the first communication station to the second communication station. [ Fig. 15] Fig. 15 is a timing chart for simultaneously detecting a phase deviation and a deviation in time using the device configuration in Fig. 14 in the sixth embodiment. [ Fig. 16] Fig. Figure 16 is a timing diagram showing an example of a sequence according to a standard protocol of the IEEE 1588 standard according to the prior art. Description of Embodiments

[0049] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, like reference numerals are used for devices having the same or similar functions unless otherwise indicated.

[0050] In the following embodiments, a method for detecting a synchronization discrepancy between two communication stations selected from two or more communication stations will first be described. Then, examples for extending this detection method to three or more communication stations will be described.

[0051] The time in the following description means a time recorded as digital information (hereinafter referred to as counter time) or a time derived from an integrated phase (hereinafter referred to as phase time). The phase time is understood as follows. That is, the integrated phase of a predetermined time point of a clock signal / clock signal is a sum of a multiple of 2π rad and a phase less than 2π rad, and the multiple alone is the phase time. Furthermore, the range of a phase and a phase difference in the following description is limited to a value of 2π rad or less. For example, if correct counter time information is not transmitted due to noise in the communication path, or if unwrapping of a phase difference is not performed appropriately, a deviation will occur between the counter time and the phase time. [First embodiment]

[0052] Each of the block diagrams in the Fig. 1 and Fig. Figure 2 illustrates a device configuration example to which the present invention is applied, where (Φ) is the configuration example related to a phase, and (t) is the configuration example related to time. In each wireless communication station A in the configuration examples in Fig. 1 (Φ) and (t) is each of the frequency generator (2) generating a clock / clock X and the frequency generator (1) generating a clock / clock A intended for input to a receiver and demodulator (4), a configuration example of a self-regulating frequency generator. At each wireless communication station B in Fig. 2 (Φ) and (t) show a configuration example in which a frequency generator (1) generating a clock B via the receiver and demodulator (4) is operated in phase synchronization with the frequency generator (1) generating the clock A in the communication station A. It should be noted that the transmission and reception between the communication stations A and B are performed using the same frequency and are managed by a computer 7 under time-sharing.

[0053] Communication stations A and B have essentially the same circuit configuration, but the synchronization of the frequency generator (1) with another station is switched using an external signal. The present invention is applicable to the synchronous and non-synchronous adjustment of communication station B with the frequency generator (1) of the communication station.

[0054] Although wireless communication is performed in these configuration examples, the present invention is applicable to any environment in which signals described below can be transmitted, and is easily applicable to wired communication using an electric wire, an optical fiber, and the like.

[0055] In Fig. 1, a signal from clock / clock generator X, contained in an electromagnetic wave input through an antenna 12, and from clock / clock generator A from frequency generator 1 are mixed in receiver and demodulator 4, and their phase difference is measured by a carrier wave phase and reception time analyzer (6). The measurement result is input to the computer (7). The computer (7) receives information from communication station B, which has been demodulated by the receiver and demodulator (4), through a reception information decoder (5). This information is time information or phase information and may include information about the synchronous / non-synchronous setting described above. In the example of Fig. 1, the information about the synchronous / non-synchronous setting is transmitted from the computer (7) to a controller 20. Since a feedback signal used for synchronization is a pulse / clock signal, the computer (7) performs control during intervals between feedback signals. This control can be control to maintain a control signal while the feedback signal is absent, or non-linear control, such as proportional-integral-derivative (PID) control. The computer (7) also controls the transmission of a transmitter (3X) to implement time-sharing communication at the common frequency. The computer (7) further performs control regarding transmission details and transmission time from the transmitter (3X), stores data necessary for detecting a synchronization deviation, including the integration of phases and phase differences, and performs data processing.

[0056] Fig. Figure 2 shows the configuration example of communication station B, where (Φ) is the configuration example with respect to phase and (t) is the configuration example with respect to time. As described above, the difference from communication station A is that the clock of the frequency generator (1) of the own station (communication station B) is synchronized with the frequency generator (1) of communication station A.

[0057] Fig. 3 and Fig. Figure 4 shows configuration examples for avoiding time-sharing operation, using two frequencies. (Φ) is the configuration example related to phase, and (t) is the configuration example related to time. That is, the antenna, receiver, and demodulator are divided into those for receiving an electromagnetic wave from a virtual reference station of the own station and those for receiving an electromagnetic wave from the partner station. Fig. 3 shows the configuration example of the communication station A and Fig. 4 shows the configuration example of communication station B.

[0058] These configuration examples are advantageous in that sending and receiving can be performed simultaneously. Accordingly, the transmission time and any deviation in time can be measured more accurately than in the case of the configurations in the Fig. 1 and Fig. 2, especially when the antenna position is moving. Furthermore, the temporal deviation can be detected more frequently to obtain more detailed information.

[0059] Fig. Fig. 7 is a timing chart illustrating a sequence in which the method for detecting a synchronization deviation between communication stations according to the present invention is applied to the device configurations in Fig. 1 and Fig. 2 and Fig. 3 and Fig. 4 is applied, in terms of time. It should be noted that in the Fig. 1 and Fig. 2 and Fig. 3 and Fig. 4 the diagrams (Φ) refer to the phase and the diagrams (t) refer to the time, in the first embodiment.

[0060] First, this method is a method of detecting, in a first communication station (i.e., communication station A transmitting a signal synchronized with clock X) and a second communication station (i.e., communication station B transmitting a signal synchronized with clock Y), selected from two or more communication stations connected to each other via a communication method so as to be able to communicate with each other, a time difference between the time (i.e., the time based on clock A) of the first communication station and the time (i.e., the time based on clock B) of the second communication station, the communication stations timing the time in a consistent manner.

[0061] Predetermined blank information is selected from among transmission time information (TXA) from the first communication station to the second communication station, transmission time information (TYB) from the second communication station to the first communication station, reception time (TXB) of a clock at the second communication station when transmitted from the first communication station to the second communication station, and reception time (TYA) of a clock at the first communication station when transmitted from the second communication station to the first communication station. The transmission time information of each station in this case is the reception time at which a signal transmitted from the transmitter (3) of its own station was received by the receiver and demodulator (4, 4X, or 4Y) of its own station.

[0062] (1) The first communication station sends a signal for synchronization at time SA1 in Fig. 7 and receives and records the transmission time T1XA of the synchronization signal at time RA1. A1 represents the details of a register A provided in the computer (7) of the communication station A at that time.

[0063] (2) The second communication station receives the synchronization signal at RB1 and records the reception time T1XB of the synchronization signal. B1 represents the details of a register B provided in the computer (7) of communication station B at this time.

[0064] (3) The second communication station sends a synchronization signal T1XB to SB1 and receives and records the transmission time T1YB of the synchronization signal at RB2. B2 represents the details of register B at this time.

[0065] (4) The first communication station receives the synchronization signal and T1XB at RA2 and records the reception time T1YA of the synchronization signal. A2 represents the details of register A at this time.

[0066] (5) The first communication station transmits at SA2, selected from the synchronization signal, T1XA, and T1YA, at least T1XA and T1YA. A3 represents the details of register A obtained as a result of reception.

[0067] (6) The second communication station receives at least T1XA and T1YA selected from the synchronization signal, T1XA, and T1YA. B3 represents the details of register B at this time.

[0068] (7) The second communication station transmits at least T1YB at SB2.

[0069] (8) The first communication station receives at least T1YB at RA4. A4 represents the details of register A at this time.

[0070] In a process including this sequence, for a set of input values ​​of T1XA, T1XB, T1YA and T1YB, a transmission time of the signal (Tp) between the first communication station and the second communication station is determined at each communication station based on an arithmetic mean of an increase from T1XA to T1XB (ΔTX B-A ) and an increase from T1YB to T1YA (ΔTY A-B ). That is, Tp=12(ΔTXB−A+ΔTYA−B)=12[(T1XB−T1XA)+(T1YA−T1YB)]

[0071] The time deviation (Tc) between the first communication station and the second communication station is calculated by subtracting the gain (ΔTX B-A ) from the transmission time (Tp) or by subtracting the transmission time (Tp) from the increase (Δ TY A-B ). That is, Tc = Tp - (T1XB - T1XA) = (T1YA - T1YB) - Tp, where the following representation is also possible. Tc==12(ΔTYA−B−ΔTXB−A) [Second embodiment]

[0072] Fig. Fig. 8 is a timing chart illustrating a sequence in which a method for detecting a synchronization deviation between communication stations according to the present invention is applied to the device configurations in Fig. 1 and Fig. 2 and Fig. 3 and Fig. 4 is applied, expressed in terms of phase. This is an example of a method for detecting a deviation of the clock phase in the first communication station (A) and the second communication station (B) selected from two or more communication stations connected by a communication method so that they can communicate with each other.

[0073] Furthermore, in this embodiment, the communication stations each clock in a corresponding / consistent manner. In addition, the second communication station receives a first communication station signal transmitted by the first communication station and transmitted as a signal synchronized with the clock X of the first communication station, and the first communication station receives a second communication station signal transmitted by the second communication station and transmitted as a signal synchronized with the clock signal (Y) of the second communication station. The first and second communication station signals have a phase difference that is converted into a predetermined common frequency.The transmission phase difference information of each station in this case is the phase difference obtained by comparing a signal transmitted from the transmitter (3X, 3Y) of its own station and received by the receiver and demodulator (4, 4X or 4Y) of its own station to the phase of clock A or clock B of its own station.

[0074] (1) The first communication station sends the signal of the first communication station at time SA1 in Fig. 8, receives the transmitted signal of the first communication station at time RA1 and measures and records a phase difference (Φ1XA) between the transmitter X of the received first communication station signal and the clock A of the first communication station signal. A1 represents the details of register A provided in the computer (7) of the communication station A at this time.

[0075] (2) The second communication station receives the first communication station signal at RB1 and measures and records a phase difference (Φ1XB) between the received first communication station signal and the clock B of the second communication station signal. B1 represents the details of the register B provided in the computer (7) of the communication station B at this time.

[0076] (3) The second communication station transmits the second communication station signal and the phase difference (Φ1XB) at SB1, receives the transmitted signal of the second communication station at RB2, and measures and records a phase difference (Φ1YB) between the received second communication station signal and the clock B of the second communication station signal. B2 represents the details of register B at this time.

[0077] (4) The first communication station receives the second communication station signal and the phase difference (Φ1XB) at RA2, and measures and records a phase difference (Φ1YA) between the received second communication station signal and the clock A of the first communication station signal. A2 represents the details of register A at this time.

[0078] (5) The first communication station transmits the first communication station signal, the phase difference (Φ1XA), and the phase difference (Φ1YA) at SA2, and receives the transmitted first communication station signal at RA3. A3 represents the details of register A obtained as a result of reception at RA3.

[0079] (6) The second communication station receives at least the phase difference (Φ1XA) and the phase difference (Φ1YA) selected from the first communication station signal at RB3. B3 represents the details of register B at this time.

[0080] (7) The second communication station transmits at least the phase difference (Φ1YB) at SB2.

[0081] (8) The first communication station receives at least the phase difference (Φ1YB). A4 represents the details of register A at this time.

[0082] For the phase difference ΔX obtained by subtracting the phase difference (Φ1XA) from the phase difference (Φ1XB), and the phase difference ΦY obtained by subtracting the phase difference (Φ1YB) from the phase difference (Φ1YA), a transmission phase difference (Φp) between the first communication station and the second communication station is derived based on an arithmetic mean of the phase differences ΦX and ΦY. That is, Φp=(ΦX+ΦY) / 2

[0083] Furthermore, a phase difference (Φc) due to a time deviation in the second communication station from the time of the first communication station is derived based on an arithmetic mean of the phase differences ΦX and -ΦY. That is, Φc=(ΦX−ΦY) / 2

[0084] It should be noted that in Fig. 1 or Fig. 3 the phase data to be entered into the transmitter 3X in Fig. 8 A4 and the phase data to be output from the carrier wave phase and reception time analyzer 6 and the reception information decoder 5 are those shown in Fig. 8 can be received at RA4. Similarly, in Fig. 2 or Fig. 4 the phase data to be entered into the transmitter 3X in Fig. 8 B3 and the phase data to be output from the carrier wave phase and reception time analyzer 6 and the reception information decoder 5 are those shown in Fig. 8 can be received at RB3. [Third Embodiment]

[0085] The Fig. 5 and Fig. 6 illustrates device configuration examples in which the transmitting antenna and the receiving antenna are split. In these configurations, clock A or a signal synchronized with clock A is used instead of clock X of the communication station A. Also, in the communication station B, clock B or a signal synchronized with clock B is used instead of clock Y. In addition, a split antenna 13 is used as the transmitting antenna and the receiving antenna, and transmission and reception are switched using a directional coupler. In such an antenna system, a slight deviation in impedance matching causes a wave reflected from the antenna to be input to the receiver and demodulator 4. In this embodiment, a transmission timestamp is obtained using the reflected wave.That is, the transmission time information (TXA) from the first communication station to the second communication station and the transmission time information (TYB) from the second communication station to the first communication station are each measured by receiving a reflection signal from a corresponding antenna.

[0086] When a reflection signal cannot be obtained with sufficient intensity in the case of wired transmission using a coaxial cable, an optical fiber, or the like, a point where the transmission impedance is discontinuous is provided as a transmission end / transmission end point on the transmission path and is used as a reflection point for the transmission / reception signal, and any deviation in phase or time at the time of passing can be detected thereby.

[0087] This configuration is advantageous in that the propagation paths of the electromagnetic waves can be completely consistent with each other, and thus a condition for equal propagation time of the electromagnetic orbital wave can be realized between the communication stations A and B, which are assumed to detect a synchronization deviation. Furthermore, in this embodiment, the communication stations A and B serve as the master and slave, respectively, and the clock of the communication station B is set to be synchronized with that of the communication station A.

[0088] Fig. 5 is an example of the communication station A, where Fig. 5 (Φ) the configuration example regarding the phase and Fig. 5(t) is the configuration example regarding time. The clock signal contained in the electromagnetic wave input through the antenna (13) and a directional coupler (14) and the clock A from the frequency generator (1) are mixed in the receiver and demodulator (4), and their phase difference is measured by the carrier wave phase detector (6). In this example, the clock A is generated by autonomous oscillation. The output from the carrier wave phase and reception time analyzer (6) is input to the computer (7). The computer (7) also receives information from the communication station B that has been demodulated by the receiver and demodulator (4). This information is time information or phase information and may include information about the synchronous / non-synchronous setting described above. In the example of Fig. 5, the information about the synchronous / non-synchronous setting is supplied from the receiver and demodulator (4) to the received information decoder (5), the computer (7), and the controller (20). The computer (7) controls the transmission of the transmitter (3X) to implement two-way communication at the common frequency. The computer (7) further performs control regarding transmission details and transmission time of the transmitter (3X), stores data necessary for detecting synchronization deviation, and performs data processing. A signal from the transmitter (3X) is based on the clock from the frequency generator (1) and is transmitted through the directional coupler (14) and the antenna (13).

[0089] Fig. 6 is an example of communication station B. The difference to the configuration in Fig. 5 is that the clock B of the frequency generator (1) is not generated by autonomous oscillation, but is controlled by the computer (7) so that it is synchronized with the integrated phase of the communication station A. This synchronization can be a time synchronization or a phase synchronization.

[0090] As in this case where the transmission time is determined by measuring the time of a wave reflected from the antenna, the object of the present invention can be achieved by carrying out the sequence in the second embodiment.

[0091] Next, an example is illustrated in which the transmission from communication station A and communication station B is a transmission at a fixed time and at a predetermined time with a predetermined time difference. That is, in this case, a deviation of the transmission time from a scheduled transmission time is negligible, and it is not necessary to measure the transmission time by receiving a reflection signal from the antenna. Fig. Fig. 9 is a timing chart showing a sequence for synchronization control by detecting a synchronization deviation between the communication station A and the communication station B in Fig. 5 and Fig. 6 explains a case of using the scheduled transmission time as the transmission time. Accordingly, in the first and second communication stations, which are selected from two or more communication stations connected to each other via a communication method to enable communication, a time discrepancy between the time (clock A) of the first communication station and the time (clock B) of the second communication station is detected. The communication stations each clock the time in a consistent manner.

[0092] A predetermined empty information is transmitted in case of transmitting an indefinite time information selected from transmission time information (TXA) from the first communication station to the second communication station, transmission time information (TYB) from the second communication station to the first communication station, reception time (TXB) of a clock at the second communication station when transmitted from the first communication station to the second communication station and reception time (TYA) of a clock at the first communication station when transmitted from the second communication station to the first communication station. In addition, the transmission time information (TXA) transmitted by the first communication station is used as a signal for synchronization transmitted by the first communication station, and the transmission time information (TYB) transmitted by the second communication station is used as a signal for synchronization transmitted by the second communication station.

[0093] (1) The first communication station sends a scheduled transmission time T1XA at ​​time SA1 in Fig. 9 and records the transmission time T1XA. A1 represents the details of register A provided in the computer (7) of communication station A at this time.

[0094] (2) The second communication station receives T1XA at ​​the time of RB1 and records its reception time T1XB. B1 represents the details of register B provided in the computer (7) of communication station B at this time.

[0095] (3) The second communication station transmits T1XB and its scheduled transmission time T1YB at SB1 and records the transmission time T1YB of T1XB.

[0096] (4) The first communication station receives T1XB and T1YB at RA1 and records their reception time T1YA. A1 represents the details of register A at this time.

[0097] (5) The first communication station transmits at least T1YA at SA2 of T2XA and T1YA.

[0098] (6) The second communication station receives at least T1YA at RB2. B2 represents the details of register B at this time.

[0099] In a process including this sequence, for a set of input values ​​of T1XA, T1XB, T1YA, and T1YB, a transmission time of the signal (Tp) between the first communication station and the second communication station is derived for each communication station based on an arithmetic mean of an increase (ΔTXB-A) from T1XA to T1XB and an increase (ΔTYA-B) from T1YB to T1YA. That is, Tp=12[(T1XB−T1XA)+(T1YA−T1YB)]

[0100] The time deviation (Tc) between the first communication station and the second communication station is determined by subtracting the gain (ΔTXB-A) from the transmission time or by subtracting the transmission time from the gain (ΔTYA-B). That is, Tc = Tp - (T1XB - T1XA) = (T1YA - T1YB) - Tp, where the following representation is also possible. Tc=12[(T1YA−T1YB)−(T1XB−T1XA)]

[0101] The time deviation between the communication stations A and B can be easily resolved using this Tc. [Fourth Embodiment]

[0102] Fig. 10 is a timing chart example illustrating a sequence in which the method for detecting a synchronization deviation between communication stations according to the present invention is applied to the device configurations in Fig. 5 and Fig. 6 is applied with respect to the phase. In these configurations in Fig. 5 and Fig. 6, instead of the clock / clock X of the communication station A, the clock A or a signal synchronized with the clock A is used. In the communication station B, too, the clock B or a signal synchronized with the clock B is used instead of the clock Y. Furthermore, this embodiment illustrates an example in which the transmission from the communication station A and the communication station B is transmission using a certain phase and a predetermined phase difference, and illustrates an example in which, for example, a phase difference by which the phase difference is offset is added in advance. That is, this example is a case in which the deviation of a transmission phase from a scheduled transmission phase is negligible.

[0103] In the case of determining the transmission time by measuring the time of a wave reflected from the antenna, the object of the present invention can be achieved by executing the sequence in the second embodiment.

[0104] This is a method of detecting, in the first communication station (A) and the second communication station (B), selected from two or more communication stations connected to each other via a communication method so as to be able to communicate with each other, a deviation in the clock timing phase.

[0105] The communication stations each clock the time accordingly. The second communication station receives a first communication station signal, which is transmitted by the transmitter (3X) of the first communication station and is synchronized with the signal of clock A (= clock X) of the first communication station, and the first communication station receives a second communication station signal, which is transmitted by the transmitter of the second communication station (3Y) and is synchronized with the signal of clock B (= clock Y) of the second communication station.When the first and second communication transmitter signals have a phase difference which is converted into a predetermined common frequency, the phase difference between the first communication station signal transmitted from the first communication station and the received first communication station signal is a predetermined phase difference (ΦA), and the phase difference between the second communication station signal transmitted from the second communication station and the received second communication station signal is a predetermined phase difference (ΦB), the following sequence is executed.

[0106] (1) The first communication station transmits the first communication station signal and the value of the phase difference (ΦA) at time SA1 in Fig. 10. A1 represents the details of register A provided in the computer (7) of communication station A at this time.

[0107] (2) The second communication station receives the first communication station signal and the phase difference value (ΦA) at time RB1, and measures and records a phase difference (Φ1XB) between the received first communication station signal and the second communication station signal. B1 represents the details of register B provided in the computer (7) of communication station B at this time.

[0108] (3) The second communication station transmits the second communication station signal, the value of the phase difference (ΦB) and the value of the phase difference (Φ1XB) at SB1.

[0109] (4) The first communication station receives the second communication station signal, the phase difference value (ΦB), and the phase difference value (Φ1XB) at RA1, and measures and records a phase difference (Φ1YA) between the received second communication station signal and the first communication station signal. A2 represents the details of register A at this time.

[0110] (5) The first communication station transmits at least the value of the phase difference (Φ1YA) at SA2.

[0111] (6) The second communication station receives at least the phase difference value (Φ1YA) at RB2. B2 represents the details of register B at this time.

[0112] As long as there is no deviation, the phase differences ΦA and ΦB only need to be exchanged once and do not need to be exchanged multiple times. Here, for a phase difference ΦX obtained by subtracting the phase difference (ΦA) from the phase difference (Φ1XB) and a phase difference ΦY obtained by subtracting the phase difference (ΦB) from the phase difference (Φ1YA), a transmission phase difference (Φp) between the first communication station and the second communication station is derived based on an arithmetic mean of ΦX and the phase difference ΦY. Therefore, the following is satisfied. Φp=(ΦX+ΦY) / 2

[0113] Furthermore, a phase difference (Φc) due to a deviation of the time at the second communication station from the time at the first communication station is derived based on an arithmetic mean of the phase differences ΦX and -ΦY. That is, the following is satisfied. Φc=(ΦX−ΦY) / 2

[0114] The phase difference due to the time deviation between the communication stations A and B can be easily resolved using this Φc.

[0115] It should be noted that the phase data shown in Fig. 5 are to be entered into the transmitter 3X, in Fig. 10 A3, and the phase data to be output from the carrier wave phase and reception time analyzer 6 and the reception information decoder 5 are those shown in Fig. 10 at RA2. Similarly, the phase data input to the transmitter 3Y in Fig. 6 are to be entered, B2 in Fig. 10 and the phase data 5 to be output from the carrier wave phase and reception timing analyzer 6 and the reception information decoder is that received at RB2 in 10.

[0116] In each of the embodiments described above, an offset phase difference generated in the first communication station or the second communication station from the corresponding receiving point to the phase difference measuring point is desirably used to correct the received phase difference. [Fifth Embodiment]

[0117] Fig. Figure 11 is a block diagram illustrating a configuration example of communication station A for simultaneously detecting a phase deviation and a timing deviation. Communication station B may have a configuration with substantially the same block diagram. Although the configuration of this block diagram is similar to the block diagram in Fig. 1, time synchronization and phase synchronization are performed simultaneously. A time counter (1t) that measures the number of clocks from the frequency generator is included in a clock unit, and instead of the carrier wave phase detecting means, a carrier wave phase and reception time detecting means (6r) is included, which detects the reception time of the clock signal X for the transmitter (3X) of the own station and a clock signal Y for the transmitter (3Y) of the communication station B. The functions of the computer (7) include a correction of the counter time detecting unit (71), a correction of the phase time detecting unit (72), a time correction unit (73), and a frequency correction unit (74).The correcting counter time acquisition unit (71) acquires a time difference for correction obtained by exchanging information with the communication station B from the output of the carrier wave phase and reception time analyzer (6r) and the output of the reception information decoder (5). The correcting phase time acquisition unit (72) acquires a phase difference for correction in response to the output of the reception information decoder (5) and performs an unwrapping process in response to the output of the carrier wave phase and reception time analyzer (6r) when the phase is wrapped to exceed a predetermined range of 2π.In response to the correction output of the counter time acquisition unit (71), the time correction unit (73) outputs counter value correction information for the time counter (1t) and outputs phase time difference information to the frequency correction unit (74). In response to the phase lock point (phase synchronization point) correction information from the time correction unit (73) and the correction output of the phase time acquisition unit (72), the frequency correction unit (74) controls the advance and delay of the frequency generator (1).

[0118] Fig. 12 is a block diagram illustrating a configuration example of communication station A, in which the antenna and the receiver and demodulator are divided into those for receiving an electromagnetic wave from the transmitter (3X) of the own station and those for receiving an electromagnetic wave from the partner station, for simultaneously detecting a phase deviation and a timing deviation by using two frequencies. Communication station B may have a configuration with substantially the same block diagram. The configuration of this block diagram is similar to the block diagram in Fig. 3, and time synchronization and phase synchronization are performed simultaneously. That is, the time counter (1t) that measures the number of clocks from the frequency generator is incorporated into a clock unit, and a carrier wave phase and reception time analyzer (6X) that also acquires the reception time of the clock X signal from the transmitter (3X) of the own station, and a carrier wave phase and reception time analyzer (6y) that also acquires the reception time of the clock Y from the transmitter (3Y) of the communication station B are included. In addition, the functions of the computer (7) include the counter time acquisition unit (71) correction, the phase time acquisition unit (72) correction, the time correction unit (73), and the frequency correction unit (74).The correcting counter time acquisition unit (71) acquires the output from the carrier wave phase and reception time analyzer (6X), the output from the carrier wave phase and reception time analyzer (6Y), and the output from the reception information decoder (5). The correcting phase time acquisition unit (72) outputs a phase difference for correction to the time correction unit (73) in response to the output from the reception information decoder (5), and performs an unwrapping process in response to the output from the Y-carrier wave phase and reception time analyzer (6Y) when the phase is wrapped to exceed a predetermined range of 2π.In response to the correction output of the counter time acquisition unit (71), the time correction unit (73) outputs counter value correction information for the time counter (1t) and outputs phase time difference information to the frequency correction unit (74). In response to the phase lock point (phase synchronization point) correction information from the time correction unit (73) and the correction output of the phase time acquisition unit (72), the frequency correction unit (74) controls the advance and delay of the frequency generator (1).

[0119] Fig. 13 illustrates a timing diagram for simultaneously detecting a phase deviation and a time deviation using the device configuration in Fig. 11 or Fig. 12. In a case of an N-th exchange of phase information and time information exchanged between the communication stations A and B, the register A of the computer (7) of the communication station A becomes as follows. N-te in Station A: Phase (Φ N-1 XA, F n-1 YA, F N-1 XB, F n-2 YB) Oil (T ABS N-1 XA, T ABs n-1 NO, T ABS N-1 XB, T ABS n-2 YB) <N-tes Senden>

[0120] [A] Station A transmits a carrier wave which is modulated using the information from register A: Phase (Φ N-1 XA, Φ n-1 YA), Time (T ABS N-1 XA, T ABS n-1 YA).

[0121] This carrier wave is received by the receiver and demodulator (4) of the communication station A, and as a result of the signal processing in the communication station A, (Φ N XA, T ABS N XA). As a result, register A becomes as follows. Phase (Φ N XA, Φ n-1 YA, Φ N-1 XB, Φ n-2 YB), Time (T ABS N XA, T ABsn-1 YA, T ABS N-1 XB, T ABS n-2 YB)

[0122] This carrier wave is received by the receiver and demodulator (4) of the communication station B, and as a result of the signal processing in the communication station B, (Φ N XB, T ABS N XB). As a result, the information stored in register B of the computer (7) of the communication station B is as follows. Phase (Φ N-1 XA, Φ n-1 YA, Φ N XB, Φ n-1 YB), Time (T ABS N-1 XA, T ABs n-1 YA, T ABS N XB, T ABS n-1 YB)

[0123] [B] Communication station B then sends the following information. Phase (Φ N XB, Φ n-1 YB), Time (T ABS N XB, T ABs n-1 YB)

[0124] This signal is received by the own station and it is (Φ n YB\, T ABS n YB). Register B is as follows. Phase (Φ N-1 XA, Φ n-1 YA, Φ N XB, Φ n YB), Time (T ABS N-1 XA, T ABS n-1 YA, T ABS N XB, T ABS N YB)

[0125] This signal is received by the communication station A, and as a result of signal processing (Φ n YA, T ABS n YA). Together with the received information, register A is configured as follows. Phase (Φ N XA, Φ n YA, Φ N XB, Φ n-1 YB), Time (T ABS N XA, T ABS n YA, T ABS N XB, T ABS n-1 YB) <(N+1)-th send>

[0126] [A] Communication station A then sends the following information. Phase (Φ N XA, Φ n YA), Time (T ABS N XA, T ABS n YA)

[0127] This signal is received by the own station and as a result of signal processing (Φ N+1 XA, T ABS N+1 XA). Phase (Φ N+1 XA, Φ n YA, Φ N XB, Φ n- YB), Time (T ABS N+1 XA, T ABS n YA, T ABS N XB, T ABS n-1 YB)

[0128] The signal is received by the communication station B, and as a result of signal processing, (Φ N+1 XB, T ABS N+1 XB). Together with the received information, register B is configured as follows. Phase (Φ N XA, Φ n YA, Φ N+1 XB, Φ n YB), Time (T ABS N XA, T ABS n YA, T ABS N+1 XB, T ABS n YB)

[0129] [B] Communication station B then sends the following information. Phase (Φ N+1 XB, Φ n YB), Time (T ABS N+1 XB, T ABS n YB)

[0130] This signal is received by the communication station A, and as a result of signal processing (Φ n+1 YA, T ABS n+1 YA). Together with the received information, register A is configured as follows. Phase (Φ N+1 XA, Φ n+1 YA, Φ N+1 XB, Φ n YB), Time (T ABS N+1 XA, T ABs n+1 YA, T ABS N+1 XB, T ABS n YB)

[0131] By using the values ​​of the Nth and nth indices, both communication stations can obtain the following values: Phase (Φ N XA, Φ n YA, Φ N XB, Φ n YB), Time (T ABS N XA, T ABS n YA, T ABS N XB, T ABS n YB). If ΔTNABSX=TNABSXA−TNABSXBΔTnABSY=TnABSYB−TnABSYAΔΦNX=ΦNXA−ΦNXBΔΦnY=ΦnYB−ΦnYA

[0132] is met, the signal transmission time between the communication stations A and B is calculated based on an average of ΔT ABS N X and ΔT ABS n Y is determined, and a time deviation is calculated based on an average of ΔT ABS N X and (-1) × ΔT ABS n Y. Similarly, a phase difference for signal transmission is determined based on an average value of ΔΦ N X and ΔΦ nY is determined, and a deviation in the phase is calculated based on an average value of ΔΦ N X and (-1) × ΔΦ n Y determined.

[0133] Regarding the quotient obtained by dividing the time difference by the cycle length of a clock / clock and the remainder, the quotient is sent to the time counter to be corrected, and the remainder is used to correct the phase lock point for fine-tuning the time. Furthermore, when correcting the phase lock point, a phase that exceeds 2π is desirably gradually transferred to the integrated phase by a value sufficiently smaller than 2π.

[0134] When the phase deviation and the timing deviation are detected simultaneously as in the above case, the phase is first securely locked, and then the time difference is repeatedly measured in this state, which can measure the time difference more accurately. [Sixth Embodiment]

[0135] Fig. 14 is a block diagram showing a configuration example in which a signal synchronized with the clock A is used as the clock X of the communication station A as shown in Fig. 5 is used and the clock A, for example, is divided. Also, in the communication station B, a signal synchronized with the clock B is used as the clock Y. In addition, the divided antenna (13) is used as the transmitting antenna and the receiving antenna, and the transmitting and receiving are switched using a directional coupler.

[0136] The configuration of this block diagram includes a transmission time detecting means (9), the time counter (1t) that measures the number of clocks from the frequency generator (1) in a clock unit, and the carrier wave phase and reception time analyzer (6r) that detects the reception time of the signal from clock X of the own station and the signal from clock Y of the communication station B. The functions of the computer (7) are different in that the functions of correcting the counter time detecting unit (71), correcting the phase time detecting unit (72), the time correcting unit (73), and the frequency correcting unit (74) are included.The correction of the counter time acquisition unit (71) differs in that a time difference for correction is obtained by exchanging information with the communication station B from the output of the carrier wave phase and reception time analyzer (6r) and the output of the reception information decoder (5). The correction of the phase time acquisition unit (72) acquires a phase difference for correction in response to the output of the reception information decoder (5) and performs an unwrapping process in response to the output of the carrier wave phase and reception time analyzer (6r) when the phase is wrapped to exceed a predetermined range of 2π.In response to the output from the correction of the counter time acquisition unit (71) and the correction of the phase time acquisition unit (72), the time correction unit (73) outputs correction information of the counter value for the time counter (1t) and outputs phase time difference information for the frequency correction unit (74).

[0137] The transmission time of a signal from the transmitter (3X) is detected by the transmission time detecting means (9). This transmission time is determined, for example, based on a pulse train generated from a signal from the frequency generator 1. If a slight error is permissible, the transmission time can be corrected in a predetermined manner according to an instruction from the computer 7 and used as the transmission time. As in the case of the above-described first embodiment or the like, the accurate transmission time can be obtained by having the receiver and demodulator 4 actually subject the transmitted signal to signal processing using the clock signal from the frequency generator 1.

[0138] The antenna system as it is in Fig. As shown in Figure 14, a slight deviation in the impedance matching causes a wave reflected from the antenna to be input to the receiver and demodulator (4). In this embodiment, a transmission time stamp is obtained using the receiver and demodulator (4) or the transmission time detector (9). That is, the transmission time information (TXA) from the first communication station to the second communication station and the transmission time information (TYB) from the second communication station to the first communication station are each measured by receiving a reflection signal from a corresponding transmission endpoint.

[0139] As in Fig. 5 and Fig. 6, when a reflection signal having a sufficient intensity cannot be obtained in the case of wired transmission using a coaxial cable, an optical fiber, or the like, a point where the transmission impedance is discontinuous is provided as a transmission end point on the transmission path to be used as a reflection point for the transmission signal, and a deviation in phase or time at the time of passing therethrough can be detected.

[0140] Next, Fig. 15 is a timing diagram for simultaneously detecting a phase deviation and a time deviation in the case of using the device configuration in Fig.14. In the following description, unlike the third or fourth embodiment, the time of a wave reflected from the antenna is measured and used as the transmission time. However, since clock X and clock A are substantially the same, and clock Y and clock B are substantially the same, Φ N-1 XA and Φ n-1 YB are fixed values. Pre-measurement and adjustment can reduce measurement time and transmission information. Accordingly, these are treated as ΦXA ​​and ΦYB.

[0141] However, when the broadcast time is detected by the broadcast time detecting means 9 as in the above case, and when the broadcast time is corrected according to an instruction from the computer 7 in a predetermined manner to be used as the broadcast time, the broadcast time can be treated equally as described below.

[0142] In a case of an N-th exchange of phase information and time information exchanged between the communication stations A and B, the register A of the computer (7) of the communication station A becomes as follows. N-th in station A: Phase (ΦXA, Φ n-1 YA, Φ N-1 XB, ΦYB) Time (T ABS N-1 XA, T ABS n-1 YA, T ABS N-1 XB, T ABS n-2 YB) <N-tes Senden>

[0143] [A] Station A transmits a carrier wave which is modulated using information from register A: Phase (ΦXA, Φ n-1 YA), Time (T ABS N-1 XA, T ABS n-1 YA).

[0144] This carrier wave is received by the receiver and demodulator (4) of the communication station A, and as a result of the signal processing in the communication station A, (T ABS NXA). As a result, register A is as follows. Phase (ΦXA, Φ n-1 YA, Φ N-1 XB, ΦYB), Time (T ABS N XA, T ABS n-1 YA, T ABS N-1 XB, T ABS n-2 YB)

[0145] This carrier wave is received by the receiver and demodulator (4) of the communication station B, and as a result of the signal processing in the communication station B, (Φ N XB, T ABS N XB). As a result, the information stored in register B of the computer (7) of the communication station B is as follows. Phase (ΦXA, Φ n-1 YA, Φ N XB, ΦYB), Time (T ABS N-1 XA, T ABS n-1 YA, T ABS N XB, T ABS n-1 YB)

[0146] [B] Communication station B then transmits the following information. Phase (Φ N XB), Time (T ABS N XB, T ABS n-1 YB)

[0147] This signal is received by the own station and it is (T ABS n YB). Register B is as follows. Phase (ΦXA, Φ n-1 YA, Φ N XB, ΦYB), Time (T ABS N-1 XA, T ABS n-1 YA, T ABS N XB, T ABS n YB)

[0148] This signal is received by the communication station A, and as a result of signal processing (Φ n YA, T ABS n YA). Together with the received information, register A is configured as follows. Phase (ΦXA, Φ n YA, Φ N XB, ΦYB), Time (T ABS N XA, T ABS n YA, T ABS N XB, T ABS n-1 YB) <(N+1)-th send>

[0149] [A] Communication station A then sends the following information. Phase (Φ n YA), Time (T ABS N XA, T ABS n YA)

[0150] This signal is received by the own station and as a result of signal processing (T ABS N+1 XA). At this point. Phase (ΦXA, Φ n YA, Φ N XB, Φ n YB), Time (T ABS N+1 XA, T ABS n YA, T ABS N XB, T ABS n-1 YB)

[0151] The signal is received by the communication station B, and as a result of signal processing, (Φ N+1 XB, T ABS N+1 XB). Together with the received information, register B is configured as follows. Phase (ΦXA, Φ n YA, Φ N+1 XB, ΦYB), Time (T ABS N XA, T ABSn YA, T ABS N+1 XB, T ABS n YB)

[0152] At this stage, communication station B can receive the following values. Phase (ΦXA, Φ n YA, Φ N XB, ΦYB), Time (T ABS N XA, T ABS n YA, T ABS N XB, T ABS n YB).

[0153] [B] Communication station B then sends the following information. Phase (Φ N+1 XB), Time (T ABS N+1 XB, T ABS n YB)

[0154] This signal is received by the own station and it is (T ABS n+1 YB). Register B is as follows. Phase (ΦXA, Φ n-1 YA, Φ N XB, ΦYB), Time (T ABS N-1 XA, T ABS n-1 YA, T ABS N XB, T ABS n+1 YB)

[0155] This signal is received by the communication station A, and as a result of signal processing (Φ n+1 YA, T ABS n+1 YA). Together with the received information, register A is configured as follows. Phase (ΦXA, Φ n-1 YA, Φ N+1 XB, ΦYB), Time (T ABS N XA, T ABS n+1 YA, T ABS N+1 XB, T ABS n YB)

[0156] Using the values ​​of the Nth and nth indices, if ΔTNABSX=TNABSXA−TNABSXBΔTnABSY=TnABSYB−TnABSYAΔΦNX=ΦXA−ΦNXBΔΦnY=ΦYB−ΦnYA

[0157] is satisfied, the signal transmission time between the communication stations A and B is calculated on the basis of an average of ΔT ABS N X and ΔT ABS n Y, and a deviation in time is calculated based on an average of ΔT ABS N X and (-1) × ΔT ABSn Y . Similarly, a phase difference for signal transmission is determined based on an average value of ΔΦ N X and ΔΦ n Y is determined, and a deviation in the phase is calculated based on an average value ΔΦ N X and (-1) × ΔΦ n Y determined.

[0158] In the above embodiment, when a synchronization deviation in time is detected, the phases of clocks / clocks between the communication stations A and B are synchronized with each other so as to basically limit the synchronization deviation in time to one clock cycle / clock cycle or less, and accordingly, it is obvious that the phase synchronization on a statistical basis desirably takes precedence over the time synchronization.

[0159] Regarding the phases or phase difference, if the amplitude during measurement exceeds 2π rad, it is wrapped to be 2π rad or less. However, a well-known unwrapping process is performed, for example, by synthetic aperture radar image processing. It is known that the phase can be properly handled by this method even in a range exceeding 2π rad. To perform the unwrapping process most simply, for example, if the phase jump over time is smaller than π rad, the phase remains in the last range; if the phase jump is larger, the phase exceeds the limit of the last range over time. [Seventh Embodiment]

[0160] The above-described detection of a synchronization deviation between two or more communication stations can be realized by expanding the process between two communication stations described in the above embodiments to a process between two or more communication stations. Here, a communication path between any two communication stations is found among two or more communication stations, and the order of detecting a synchronization deviation between two or more communication stations simultaneously is determined by connecting two communication stations that can communicate with each other.To this end, first, the second communication station for which the detection of a synchronization deviation with the predetermined first communication station has been completed is categorized together with the predetermined first communication station into a first communication station group, and a communication station group for which the detection of a synchronization deviation has yet to be completed is categorized into a second communication station group. Then, if a communication station selected from the second communication station group. (1) can communicate with a communication station belonging to the first communication station group, the category of the selected communication station is transferred from the second communication station group to the first communication station group, or (2) is unable to communicate with a communication station belonging to the first communication station group, a new second communication station is selected from the second communication station group, and the process returns to (1).

[0161] The above operation is performed according to an order that can be established by a method for determining the order of detecting a synchronization deviation until no communication station is categorized in the second communication station group.

[0162] According to the order, the detection of a synchronization deviation between communication stations is performed sequentially for a pair of the first communication station and the second communication station. [Eighth Embodiment]

[0163] Detecting a synchronization deviation between two communication stations is performed sequentially in the fifth embodiment. However, in this embodiment, detecting a synchronization deviation from a plurality of communication stations is performed almost simultaneously for a single communication station. To this end, the order of communication is first determined, and then the first communication station is set during operation for a single synchronization deviation detection time, and the second communication station is subsequently switched. Specifically, the following is performed.

[0164] Detecting a synchronization deviation between two or more communication stations includes categorizing a communication station determined to be capable of communication with the predetermined first communication station into a first candidate communication station group together with the first communication station, and categorizing a communication station determined not to be capable of communication into a second candidate communication station group. For a new communication station selected from the second candidate communication station group, the following procedure is performed. (1) If communication with a communication station belonging to the first candidate communication station group is possible, the category of the selected communication station is transmitted from the second candidate communication station group to the first candidate communication station group, and (2) If communication with a communication station belonging to the first candidate communication station group is not possible, a communication station is newly selected from the second candidate communication station group, and the process returns to (1).

[0165] The above operation is performed until no communication station is categorized into the second candidate communication station group to select one among orders that are feasible by a method for determining the order of a pair of communication stations for applying the method for detecting a synchronization deviation between communication stations.

[0166] Communication from the first communication station to a communication station selected as the second communication station according to the selected order is performed sequentially, and when the selected order comes to an end, communication from the last second communication station to the first communication station is performed in reverse order. Industrial applicability

[0167] By using the detected synchronization deviation in time or phase according to the present invention, the clock signal frequency can be adjusted to a phase region, but can also be used as a correction value for correcting a numerical value.

[0168] To implement a super-distributed clock for which a master clock is not specified regardless of the use of multiple clocks, it is necessary to use information about a clock deviation or a phase difference from the median, calculated according to a predetermined method, as a correction value instead of locking the time or phase. When multiple self-controlled clocks are present, the present invention is applied, and a synchronization deviation is calculated in each of the communication stations, thereby constructing a super-distributed-type clock.

[0169] Furthermore, according to the present invention, when the present invention performs wireless communication for communication between communication stations, the distance between the communication stations can be obtained from the propagation time including the phase obtained between the communication stations. When a reference distance is known, the refractive index of air during the propagation of electromagnetic waves between the communication stations and a change thereof can be obtained. It is known that the refractive index and a change thereof reflect changes in temperature and humidity, and accordingly, environmental information can be easily obtained over a wide range. List of reference symbols 1, 1t, 2 frequency generator 3 channels 4, 4X, 4Y receiver and demodulator 5 reception information decoders 6, 6X, 6Y, 6r carrier wave phase and reception time analyzer 7 computers 9 Broadcast time reception device 11, 12, 12X, 12Y, 13 Antenna 20 Control 71 Correction of counter time receiving unit 72 Correction of phase time receiving unit 73 Time correction unit 74 Frequency correction unit

Claims

[1] A method for detecting a synchronization deviation between communication stations, the method being a method for detecting, in first and second communication stations selected from two or more communication stations connected to each other via a communication method so that they can communicate with each other, a time deviation between time information transmitted by a transmitter (X) of the first communication station (A) and received by the second communication station (B), and time information transmitted by a transmitter (Y) of the second communication station (B) and received by the first communication station (A), the communication stations each clocking the time in a consistent manner, and transmitting predetermined blank information in a case of transmitting indefinite time information,selected from a transmission time information (TXA) from the first communication station to the second communication station, a transmission time information (TYB) from the second communication station to the first communication station, a reception time (TXB) of a clock at the second communication station when transmitting from the first communication station to the second communication station, and a reception time (TYA) of a clock at the first communication station when transmitting from the second communication station to the first communication station, the method being in a method which includes: (1) a step in which the first communication station transmits TXA and TYA and records the transmission time TXA, (2) a step in which the second communication station receives TXA and TYA and measures and records the reception time TXB, (3) a step in which the second communication station transmits TXB and TYB and records the transmission time TYB, and (4) a step in which the first communication station receives TXB and TYB and measures and records the reception time TYA for a set of input values ​​of TXA, TXB, TYA and TYB, comprising: Deriving a transmission time of a signal between the first communication station and the second communication station based on an arithmetic mean of an increase (ΔTXB-A) from TXA to TXB and an increase (ΔTYA-B) from TYB to TYA, at each station; or Determining the time deviation between the first communication station and the second communication station by subtracting the gain (ΔTXB-A) from the transmission time or by subtracting the transmission time from the gain (ΔTYA-B). [2] A method for detecting a synchronization deviation between communication stations, the method being a method for detecting, in first and second communication stations selected from two or more communication stations connected to each other via a communication method so that they can communicate with each other, a time deviation between time information transmitted by a transmitter (X) of the first communication station (A) and received by the second communication station (B), and time information transmitted by a transmitter (Y) of the second communication station (B) and received by the first communication station (A), the communication stations each clocking the time in a consistent manner, and transmitting dummy information in a case of transmitting indefinite time information,selected from a transmission time information (TXA) from the first communication station to the second communication station, a transmission time information (TYB) from the second communication station to the first communication station, a reception time (TXB) of a clock at the second communication station when transmitting from the first communication station to the second communication station, and a reception time (TYA) of a clock at the first communication station when transmitting from the second communication station to the first communication station, the method being in a process comprising the following steps: (1) a step in which the first communication station sends a synchronization signal and records the transmission time TXA of the synchronization signal, (2) a step in which the second communication station receives the signal for synchronization and TXA and records the reception time TXB of the signal for synchronization, (3) a step in which the second communication station sends a synchronization signal and TXB and records the transmission time TYB of the synchronization signal, (4) a step in which the first communication station receives the synchronization signal and TXB and records the reception time TYA of the synchronization signal, (5) a step in which the first communication station sends at least TXA and TYA, (6) a step in which the second communication station receives at least TXA and TYA, (7) a step in which the second communication station sends at least TYB, and (8) a step in which the first communication station receives at least TYB for a set of input values ​​of TXA, TXB, TYA and TYB, includes: Deriving a transmission time of a signal between the first communication station and the second communication station based on an arithmetic mean of an increase (ΔTXB-A) from TXA to TXB and an increase (ΔTYA-B) from TYB to TYA, at each station; or Determining the time deviation between the first communication station and the second communication station by subtracting the gain (ΔTXB-A) from the transmission time or by subtracting the transmission time from the gain (ΔTYA-B). [3] A method for detecting a synchronization deviation between communication stations according to claim 2, wherein the transmission time information (TXA) from the first communication station to the second communication station and the transmission time information (TYB) from the second communication station to the first communication station are each measured by receiving a reflection signal from a corresponding transmission end. [4] A method for detecting a synchronization deviation between communication stations according to claim 2 or 3, wherein the transmission time information (TXA) from the first communication station to the second communication station, the transmission time information (TYB) from the second communication station to the first communication station, the reception time (TXB) of a clock at the second communication station when transmitted from the first communication station to the second communication station, and the reception time (TYA) of a clock at the first communication station when transmitted from the second communication station to the first communication station are each information in a state in which phases of the clocks A and B are synchronized. [5] A method for detecting a synchronization deviation between communication stations, the method being a method for detecting, in first and second communication stations selected from two or more communication stations connected to each other via a communication method so that they can communicate with each other, a time deviation in the clock phase between a clock / clock A for generating time information transmitted by a transmitter (X) of the first communication station (A) and received by the second communication station (B), and a clock / clock B for generating time information transmitted by a transmitter (Y) of the second communication station (B) and received by the first communication station (A), the communication stations each clocking the time in a consistent manner,wherein the second communication station receives a first communication station signal transmitted by the first communication station and synchronized with a signal from clock / clock generator X of the first communication station, , the first communication station receives a second communication station signal transmitted by the second communication station and synchronized with a signal from clock Y of the second communication station, the method comprising, when the first and second communication station signals have a phase difference which is converted to a predetermined common frequency: (1) by the first communication station, transmitting the first communication station signal, receiving the transmitted first communication station signal and measuring a phase difference (ΦXA) between the received first communication station signal and a signal of the clock A from the first communication station; (2) by the second communication station, receiving the first communication station signal and measuring a phase difference (ΦXB) between the received first communication station signal and a clock B signal from the second communication station; (3) by the second communication station, transmitting the second communication station signal and the phase difference (ΦXB), receiving the transmitted second communication station signal and measuring a phase difference (ΦYB) between the received second communication station signal and the clock B signal from the second communication station; (4) by the first communication station, receiving the second communication station signal and the phase difference (ΦXB) and measuring a phase difference (ΦYA) between the received second communication station signal and the first communication station signal; (5) by the first communication station, transmitting the first communication station signal, the phase difference (ΦXA) and the phase difference (ΦYA) and receiving the transmitted first communication station signal; (6) by the second communication station, receiving at least the phase difference (ΦXA) and the phase difference (ΦYA) among the first communication station signal, the phase difference (ΦXA) and the phase difference (ΦYA); (7) by the second communication station, transmitting at least the phase difference (ΦYB); (8) by the first communication station, receiving at least the phase difference (ΦYB); and for a phase difference ΦX obtained by subtracting the phase difference (ΦXA) from the phase difference (ΦXB) and a phase difference ΦY obtained by subtracting the phase difference (ΦYB) from the phase difference (ΦYA), deriving a phase difference between the first communication station and the second communication station based on an arithmetic mean of the phase differences ΦX and ΦY, and deriving a phase difference based on a time deviation at the second communication station from the time of the first communication station based on an arithmetic mean of the phase differences ΦX and -ΦY. [6] A method for detecting a synchronization deviation between communication stations according to claim 5, wherein the phase difference (ΦXA) transmitted from the first communication station to the second communication station and the phase difference (ΦYB) transmitted from the second communication station to the first communication station are each measured by receiving a reflection signal from a corresponding transmitting end. [7] A method for detecting a synchronization deviation between communication stations according to claim 5 or 6, wherein in the measurement of the phase difference, the phase difference is an unwrapped value using a predetermined time as a starting point. [8] A method for detecting a synchronization deviation between communication stations according to any one of claims 1 to 7, wherein in the first communication station or the second communication station, the received phase difference is corrected by using an offset phase difference generated by each receiving point to a phase difference measuring point. [9] A method for detecting a synchronization deviation between communication stations according to any one of claims 1 to 8, wherein the communication between the first communication station and the second communication station is a wireless communication, and the first communication station signal or the second communication station signal is a carrier wave modulated using information including the phase difference ΦXB or ΦYA. [10] A method for detecting a synchronization deviation between communication stations according to claim 9, wherein the wireless communication between the first communication station and the second communication station is performed using a common frequency channel under time sharing. [11] A method for detecting a synchronization deviation between communication stations according to claim 9, wherein, in the wireless communication between the first communication station and the second communication station, a frequency channel in downlink communication from the first communication station to the second communication station and a frequency channel in uplink communication from the second communication station to the first communication station are different, and the downlink communication and the uplink communication are carried out in time slots partially overlapping with each other. [12] A method for detecting a synchronization deviation between communication stations according to any one of claims 1 to 8, wherein detecting a synchronization deviation between two or more communication stations includes categorizing the second communication station for which synchronization with the predetermined first communication station has been completed into a first communication station group together with the predetermined first communication station and categorizing a communication station group for which time synchronization has not yet been completed into a second communication station group, and sequentially, time synchronization is performed between communication stations for a pair of the first communication station and the second communication station according to an order, wherein the order is obtainable by a method for determining the order of time synchronization by performing the following process until no communication station is categorized in the second communication station group, in which, when a communication station selected from the second communication station group, (1) is capable of communicating with a communication station belonging to the first communication station group, the category of the selected communication station is transmitted from the second communication station group to the first communication station group, or (2) is unable to communicate with a communication station belonging to the first communication station group, a new second communication station is selected from the second communication station group, and the process returns to (1). [13] A method for detecting a synchronization deviation between communication stations according to any one of claims 1 to 8, wherein detecting a synchronization deviation between two or more communication stations comprises: categorizing a communication station determined to be able to communicate with the predetermined first communication station into a first candidate communication station group together with the first communication station, and categorizing a communication station determined to be unable to communicate into a second communication station group, Selecting one of orders that can be created by a method for determining the order of a pair of communication stations for applying the method for detecting a synchronization deviation between communication stations by performing the following process until no communication station is categorized in the second candidate communication station group, wherein for a new communication station selected from the second candidate communication station group, (1) if communication with a communication station belonging to the first candidate communication station group is possible, the category of the selected communication station is transferred from the second candidate communication station group to the first candidate communication station group, or (2) if communication with a communication station belonging to the first candidate communication station group is not possible, a new communication station is selected from the second candidate communication station group, and the process returns to (1), and Detecting a synchronization deviation between two or more communication stations by sequentially performing communication from the first communication station to a communication station selected as the second communication station according to the selected order, and, when the order comes to an end, performing communication from the last second communication station to the first communication station in the reverse order.

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