WO2022176026A1

WO2022176026A1 - Network translator and device translator

Info

Publication number: WO2022176026A1
Application number: PCT/JP2021/005744
Authority: WO
Inventors: 家佳宋; 大介滝田; 慎久保見; ジェフリジャオ; 竜真松下; 善文堀田
Original assignee: 三菱電機株式会社
Priority date: 2021-02-16
Filing date: 2021-02-16
Publication date: 2022-08-25
Also published as: TW202234920A; JP7258261B2; KR102628183B1; JPWO2022176026A1; KR20230121934A

Abstract

This network translator (210) calculates a clock deviation between a TSN master (101) and a 5G time source (111), sets the calculated clock deviation to generate a message, and transmits the generated message to a device translator (220). The device translator receives a message from the network translator, calculates a clock deviation between the TSN master and the device translator by using the clock deviation between the TSN master and the 5G time source, sets the calculated clock deviation to generate a message, and transmits the generated message to the downstream side of a time synchronization network system (100).

Description

network translator and device translator

This disclosure relates to a 5G-TSN translator that considers clock deviation.

In the time synchronization method of wired TSN over multiple stages, the link delay of each section and the clock deviation of each section are calculated by exchanging delay measurement messages between adjacent devices.
When the slave obtains the time notified from the master device, it corrects the time difference with the master device using the integrated value of the link delay in each upstream section and the integrated value of the clock deviation in each upstream section. This realizes highly accurate time synchronization.
TSN is an abbreviation for Time-Sensitive Networking.

A 5G-TSN system is a TSN system in which TSN devices are connected by wire via 5G.
In the 5G-TSN system, the 5G section is treated as one-stage virtual equipment. Physically, however, in the 5G section, a device network translator (NW-TT) is arranged on one side across the wireless section, and a device translator (DS-TT) is arranged on the other side across the wireless section.
A translator is a device having a wired TSN function, and is also called a TSN translator.

In 5G networks, the delay is different between uplink and downlink communication. Therefore, even if delay measurement messages are exchanged between the NW-TT and DS-TT, the link delay in the 5G section cannot be measured.
Therefore, NW-TT and DS-TT use the fact that the equipment in the 5G section is synchronized with the time (5G time) that is independent of the time of the TSN, and by time stamping the 5G time, the link in the 5G section Measure latency.

Non-Patent Document 1 discloses a conventional 5G-TSN network.
In a conventional 5G-TSN network, it is assumed that the clock deviation of each of the NW-TT and DS-TT to the GrandMaster (GM) of the 5G network is zero. The DS-TT then puts the clock deviation of the NW-TT with respect to the GM of the TSN into the time transfer message Sync/Follow_Up and sends the time transfer message downstream to the TSN slave.

Conventionally, there is no method for calculating the clock deviation between DS-TT and NW-TT. Therefore, the clock deviation in the 5G section is not considered. This causes a synchronization time error in the TSN slave downstream of the DS-TT.

The present disclosure aims to suppress synchronization time errors in TSN slaves downstream of DS-TT by considering clock deviations in 5G-TSN.

A network translator of the present disclosure is used in a mobile communication system provided upstream of a time synchronization network system and downstream of the time synchronization network system.
The upstream of the time synchronization network system has a master, which is a device serving as a time source of the time synchronization network system.
The mobile communication system has a time server serving as a time source for the mobile communication system and a device translator.
The device translator calculates the clock deviation between the master and the device translator using the clock deviation between the master and the time server and the clock deviation between the time server and the device translator, and the calculated clock deviation is set to generate a message, and the generated message is transmitted downstream of the time synchronization network system.
The network translator is
a clock deviation calculation unit that calculates the clock deviation between the master and the time server;
an intra-section communication unit that sets the clock deviation between the master and the time server to generate a message and transmits the generated message to the device translator.

According to the present disclosure, it is possible to consider clock deviation in 5G-TSN and suppress synchronization time errors in TSN slaves downstream of DS-TT.

1 is a configuration diagram of a time synchronization network system 100 according to Embodiment 1; FIG. 2 is a hardware configuration diagram of a translator 300 according to Embodiment 1. FIG. 3 is a functional configuration diagram of a network translator 210 according to Embodiment 1. FIG. 3 is a functional configuration diagram of a device translator 220 according to Embodiment 1. FIG. 4 is a flowchart of clock deviation calculation according to the first embodiment; FIG. 4 is a diagram showing the relationship between the clock deviation _{RNW_GM} (=CD _a ) and each time according to the first embodiment; FIG. 4 is a flowchart of link delay calculation according to the first embodiment; 4 is a flowchart of time adjustment according to Embodiment 1; 4 is a flowchart of additional message transmission (5G) according to Embodiment 1; 4 is a flowchart of additional message transmission (TSN) according to Embodiment 1; 4 is a flowchart of additional message transmission (TSN) according to Embodiment 1; 4 is a table showing a frame format of additional message Follow_Up (NW-TT→DS-TT) in Embodiment 1; 4 is a table showing a frame format of additional message Follow_Up (DS-TT→TSN) in Embodiment 1; 4 is a diagram showing a clock deviation R set in each PTP message according to the first embodiment; FIG. 4 is a supplementary diagram of the hardware configuration of the translator 300 according to the first embodiment; FIG.

In the embodiments and drawings, the same or corresponding elements are denoted by the same reference numerals. Descriptions of elements having the same reference numerals as those described will be omitted or simplified as appropriate. Arrows in the figure mainly indicate the flow of data or the flow of processing.

Embodiment 1.
The time synchronization network system 100 will be described with reference to FIGS. 1 to 13. FIG.

A time synchronization network system 100 is a time synchronization network system in which a plurality of network devices are connected via a mobile communication system.
A time-synchronized network system is a network system in which the times of a plurality of network devices are synchronized.
A network device is a device having a communication function.

Specifically, the time synchronization network system 100 is a 5G-TSN system.
5G is the fifth generation mobile communication system. A fifth generation mobile communication system is an example of a mobile communication system.
TSN is a time synchronization network system called time sensitive networking.

*** Configuration description ***
The configuration of the time synchronization network system 100 will be described based on FIG.
The time synchronization network system 100 includes a TSN master 101, a first bridge 102, a TSN slave 121 and an Mth bridge 122. These are TSN's network equipment.

The TSN master 101 is a network device that serves as a time source in TSN, and is called a grandmaster (GM). The side where the TSN master 101 is located is called "upstream".
The TSN slave 121 is network equipment that synchronizes with the time of the TSN master 101 . The side where the TSN slave 121 is located is called "downstream".
The TSN master 101 is denoted as "GM".
The TSN slave 121 is described as "SLAVE".

The first bridge 102 is the first bridge counted from the TSN master 101 on the communication path from the TSN master 101 to the TSN slave 121 . A bridge is a type of network device.
The Mth bridge 122 is the Mth bridge counted from the TSN master 101 on the communication path from the TSN master 101 to the TSN slave 121 .
The first bridge 102 is located upstream with respect to the 5G network 110 and the Mth bridge 122 is located downstream with respect to the 5G network 110 .
The first bridge 102 is denoted as "S1".
The Mth bridge 122 is denoted as "SM".

The time synchronization network system 100 includes a 5G time source 111, a network translator 210, and a device translator 220. These are the network equipment of the 5G network 110 .

The 5G time source 111 is a network device that serves as a time source for the 5G network 110, and is called a time server (TS).
The 5G time source 111 is referred to as "5G-TS".
The 5G network 110 time is independent of the TSN time.

The network translator 210 is a translator that performs 5G-TSN inter-network connection, has a TSN time synchronization function, and is arranged upstream in the 5G network 110 .
The device translator 220 is a translator that performs 5G-TSN inter-network connection, has a TSN time synchronization function, and is arranged downstream in the 5G network 110 .
Network translator 210 and device translator 220 are also referred to as TSN translators (TT).
The network translator 210 is referred to as "NW-TT".
Device translator 220 is referred to as “DS-TT”.

The hardware configuration of the translator 300 will be described based on FIG.
Translator 300 is a general term for network translator 210 and device translator 220 .

Translator 300 includes motherboard 310 and expansion card 320 .
Motherboard 310 is connected to computer 301 for control.
Motherboard 310 includes processor 311 , serial communication device 312 and translator circuit 313 . These are connected to each other via a bus. This bus is also called a data bus, and provides connection for register access (setting, reading) from the processor 311 .

The processor 311 is an electronic circuit that performs arithmetic processing, and includes a logic circuit, primary cache, and the like.
A serial communication device 312 is a device for performing serial communication. Specifically, serial communication device 312 is a UART. UART is an abbreviation for Universal Asynchronous Receiver/Transmitter.
The translator circuit 313 is an electronic circuit having a translator function. Specifically, the translator circuit 313 is an FPGA circuit, and the function of the translator is constructed with programmable logic. FPGA is an abbreviation for Field-Programmable Gate Array.

Expansion cards 320 , also called mezzanine cards or daughter cards, are connected to motherboard 310 . Specifically, the expansion card 320 is connected to a dedicated connector provided on the motherboard 310 .
The expansion card 320 has

ports

321 and 322 .
Port 321 is the port connected to TSN, and port 322 is the port connected to 5G. Specifically,

ports

321 and 322 are ports called SFP. SFP is an abbreviation for Small Form Factor Pluggable.

Based on FIG. 3, the functional configuration of the network translator 210 will be described.
The network translator 210 includes elements such as an out-of-section communication unit 211 , a delay measurement unit 212 , a time synchronization control unit 213 , a clock deviation calculation unit 214 , and an in-section communication unit 215 .
These elements are realized by translator circuit 313 .

The outside section communication unit 211 performs transmission and reception with the TSN. Also, the outside communication unit 211 receives and analyzes the frame, extracts the header and message from the received PTP frame, and terminates. In addition, the out-of-section communication unit 211 performs error check and length measurement, and discards the error frame.
In addition, the outside communication section 211 notifies the delay measurement section 212 of the transmission/reception time of the PTP frame. Therefore, the out-of-section communication unit 211 holds the 5G time (TSi) when the network translator 210 received the Sync message.
PTP is an abbreviation for Precision Time Protocol.

The delay measurement unit 212 measures delay times and clock deviations between adjacent TSN devices used for time synchronization using a two-step peer-to-peer (P2P) path delay algorithm called Pdelay_Req, Pdelay_Resp and Pdelay_Resp_Follow_Up. The clock deviation is calculated based on the time difference of the P2P delay measurement messages.
The delay measurement unit 212 generates status information regarding transmission/reception control and delay measurement functions of PTP messages (Pdelay_Req, Pdelay_Resp, Pdelay_Resp_Follow_Up).
A PTP message is a message defined in IEEE 802.1 AS.

The delay measurement unit 212 measures the transmission delay between the network translator 210 and adjacent TSN devices to measure the link delay.

The time synchronization control unit 213 adds the accumulated clock deviation with the GM and the accumulated delay with the GM calculated by the own device to the time information (GM is the starting point) distributed from the adjacent TSN device (upstream), Calculate the time synchronized with the time. This allows the synchronization time to follow the GM.

The clock deviation calculation unit 214 uses the clock deviation between the own device and the GM calculated by the delay measurement unit 212 and the clock deviation between the own device and the 5G time source calculated by the intra-section communication unit 215, and the 5G time source and the GM Calculate the clock deviation of

The intra-section communication unit 215 provides the synchronized time to the 5G time source 111 . In addition, the intra-section communication unit 215 calculates the clock deviation between its own device and the 5G time source.
In addition, the intra-section communication unit 215 stores the 5G time (TSi) when the network translator 210 receives the Sync message and the accumulated clock deviation between the GM and the 5G time source calculated by the clock deviation calculation unit 214 in the TLV1 area of the Follow_Up message. Add and send a Follow_Up message to 5G.

Furthermore, the function of each element will be described later.

A functional configuration of the device translator 220 will be described based on FIG.
The device translator 220 includes elements such as an intra-interval communication unit 221 , a delay measurement unit 222 , a clock deviation calculation unit 223 and an extra-interval communication unit 224 .
These elements are realized by translator circuit 313 .

The intra-section communication unit 221 transmits and receives with 5G. In addition, the intra-section communication unit 221, from the TLV1 area of the received Follow_Up message, the 5G time (TSi) when the network translator 210 received the Sync message, the GM calculated by the network translator 210, and the cumulative clock deviation of the 5G time source and transmits the extracted information to the delay measurement unit 222 .

The delay measurement unit 222 receives the 5G time (TSe) at the time of transmission of the Sync message from the outside communication unit 224 .
The delay measurement unit 222 uses TSi received from the intra-section communication unit 221, the cumulative clock deviation of the GM received from the intra-section communication unit 221, the cumulative clock deviation of the 5G time source, and the TSe received from the outside communication unit 224. Calculate the delay time. Then, the delay measurement unit 222 transmits the delay time inside 5G to the outside communication unit 224 .

The clock deviation calculation unit 223 uses the cumulative clock deviation of the GM and the 5G time source received from the internal communication unit 221 and the clock deviation of the own device and the 5G time source received from the outside communication unit 224 to calculate the difference between the own device and the GM. Calculate the clock deviation of Then, the clock deviation calculation unit 223 transmits the clock deviation between its own device and the GM to the outside communication unit 224 .

The outside section communication unit 224 performs transmission and reception with downstream TSN devices. Also, the outside communication unit 224 receives and analyzes the PTP frame, extracts the header and message from the received PTP frame, and terminates. In addition, the out-of-section communication unit 224 performs error check and length measurement, and discards the error frame. In addition, the out-of-section communication unit 224 notifies the delay measurement unit 222 of the 5G time (TSe) at which the Sync message was transmitted.
The outside communication unit 224 adds the internal 5G delay time calculated by the delay measurement unit 222 to the correction field of the Follow_Up message. Further, the out-of-interval communication unit 224 rewrites the TLV of the Follow_Up message to the clock deviation between its own device and the GM calculated by the clock deviation calculation unit 223 . Then, the out-of-section communication unit 224 transmits the Follow_Up message to downstream TSN devices.
Also, the outside communication unit 224 is: A clock deviation between the own device and the 5G time source is calculated and transmitted to the clock deviation calculation unit 223 .

Furthermore, the function of each element will be described later.

***Description of operation***
The operation procedure of the time synchronization network system 100 corresponds to the time synchronization method.

Based on FIG. 5, clock deviation calculation will be described.
The clock deviation calculation is a process of calculating the clock deviation CD _a between the network translator 210 and the adjacent TSN device, and is executed by the network translator 210 .
TSN equipment is TSN network equipment.
The adjacent TSN equipment is specifically the first bridge 102 .

In step S111, the outside communication unit 211 receives the first delay measurement response message Pdelay_Resp from the adjacent TSN device.
The delay measurement response message Pdelay_Resp is a response to the delay measurement request message Pdelay_Req.

In step S112, the outside section communication unit 211 acquires the first response reception time _tn .
The first response reception time tn is the reception time of the first delay measurement response message _{Pdelay_Resp} .
For example, the translator 300 time is obtained from the local operating system (OS).

In step S113, the out-of-interval communication unit 211 extracts the first response transmission time _t'n from the payload of the first delay measurement response message Pdelay_Resp_Follow_Up.
The first response transmission time _t'n is the transmission time (ResponseOriginTimestamp) of the delay measurement response message Pdelay_Resp, and is measured and set by the adjacent TSN device.

In step S114, the outside communication section 211 waits for the Nth delay measurement response message Pdelay_Resp and receives the Nth delay measurement response message Pdelay_Resp. "N" is an integer of 2 or more.

In step S115, the out-of-interval communication unit 211 acquires the N-th response reception time _tnn (PdelayRespEventIngressTimestamp).
The Nth response reception time _tnn is the reception time of the Nth delay measurement response message Pdelay_Resp.

In step S116, the out-of-interval communication unit 211 extracts the Nth request reception time _t'nn from the payload of the Nth delay measurement response message Pdelay_Resp_Follow_Up.
The N-th response transmission time _t'nn is the transmission time (ResponseOriginTimestamp) of the delay measurement response message Pdelay_Resp, and is measured and set by the adjacent TSN device.

In step S117, the delay measurement unit 212 uses the first response reception time _{tn, the first response transmission time t'n, the Nth response reception time tnn, and the Nth response transmission time t'nn} _to _determine _the clock deviation. Calculate the _CDa .
Clock deviation _CDa is the clock deviation of network translator 210 and adjacent TSN devices.

The clock deviation CD _a is calculated by calculating equation (a) below.
_CDa ₌ ( _tnn -tn)/( _t'nn - _t'n ) (a)

Based on FIG. 6, the relationship between the clock deviation _{RNW_GM} and each time will be described. The clock deviation _{RNW_GM} corresponds to the clock deviation _CDa .
NW-TT sends a delay measurement request message Pdelay_Req. _The transmission time is time t1.
The GM receives the delay measurement request message Pdelay_Req. The reception _time is time t2.
The GM sends a first delay measurement response message Pdelay_Resp. The transmission time is time _t'n .
The NW-TT receives the first delay measurement response message Pdelay_Resp. The reception time is time _tn .
The GM sends the Nth delay measurement response message Pdelay_Resp. The transmission time is time _t'nn .
The NW-TT receives the Nth delay measurement response message Pdelay_Resp. The reception time is time _tnn .
The clock deviation _{RNW_GM} is calculated by calculating equation (a) above.

Based on FIG. 7, link delay calculation will be described.
Link delay calculation is a process of calculating the link delay LD _b between the network translator 210 and the adjacent TSN device, and is executed by the network translator 210 . The link delay LD _b corresponds to the transmission delay time.

In step S121, the outside section communication unit 211 transmits a delay measurement request message Pdelay_Req to the adjacent TSN device.

_In step S122, the outside section communication unit 211 acquires the request transmission time t1.
_The request transmission time t1 is the transmission time of the delay measurement request message Pdelay_Req.

In step S123, the out-of-section communication unit 211 waits for the delay measurement response message Pdelay_Resp from the adjacent TSN device and receives the delay measurement response message Pdelay_Resp.

_In step S124, the outside section communication unit 211 acquires the response reception time t4.
The response reception time t4 is the reception time of the delay measurement response message _{Pdelay_Resp} .

In step S125, the out-of-interval communication unit ₂₁₁ extracts the request reception time t2 from the payload of the delay measurement response message Pdelay_Resp.
The request reception time t2 is the reception time ( _{RequestReceiptTimestamp} ) of the delay measurement request message Pdelay_Req, and is measured and set by the adjacent TSN device.

In step S126, the out-of-interval communication unit 211 waits for the additional message Pdelay_Resp_Follow_Up of the delay measurement response message Pdelay_Resp and receives the additional message Pdelay_Resp_Follow_Up.

In step S127, the out-of-interval communication unit 211 extracts the response transmission time t3 from the payload of the additional message _{Pdelay_Resp_Follow_Up} .
The response transmission time t3 is the transmission time (ResponseOriginTimeStamp) of the delay measurement response message _{Pdelay_Resp} , which is measured and set by the adjacent TSN device.

_In step S128, the delay measuring unit ₂₁₂ calculates the link delay _LDb using the clock deviation _CDa , the request transmission time t1, the response reception time t4, the request reception _time t2 _, and the response transmission time t3. .
Link delay LD _b is the link delay between network translator 210 and adjacent TSN equipment.

The link delay LD _b is calculated by calculating equation (b) below.
LD _b = (CD _a ×(t ₄ −t ₁ )−(t ₂ −t ₃ ))/2 (b)

Time adjustment will be described based on FIG.
Time synchronization is a process of synchronizing the time of the network translator 210 with the time of the TSN master 101 and is executed by the network translator 210 .

In step S131, the out-of-section communication unit 211 receives the synchronization message Sync from the adjacent TSN device.

In step S132, the out-of-section communication unit 211 acquires the synchronous reception time TSi.
The synchronous reception time TSi is the 5G time when the synchronization message Sync is received.

In step S133, the outside communication unit 211 waits for the additional message Follow_Up of the synchronization message Sync and receives the additional message Follow_Up. Then, the out-of-section communication unit 211 transmits the synchronization message Sync to 5G.

In step S134, the out-of-interval communication unit 211 extracts the cumulative clock deviation ACD' from the additional message Follow_Up.
Cumulative clock deviation ACD′ is the cumulative clock deviation of TSN master 101 and adjacent TSN devices of network translator 210 .

In step S135, the delay measuring unit 212 calculates the cumulative clock deviation _ACDc using the clock deviation _CDa and the cumulative clock deviation ACD'.
Cumulative clock deviation ACD _c is the cumulative clock deviation of network translator 210 and TSN master 101 .

The accumulated clock deviation ACD _c is calculated by calculating equation (c) below.
ACDc = ACD' x _CDa ( _c )

In step S136, the out-of-interval communication unit 211 extracts the accumulated delay value AD' from the Correction field of the additional message Follow_Up.
The accumulated delay value AD′ is the accumulated delay value between the TSN device adjacent to the network translator 210 and the TSN master 101 .

In step S137, the delay measurement unit 212 calculates an integrated delay _ADd using the integrated delay value AD', the link delay _LDb , and the integrated clock deviation _ACDc .
The accumulated delay AD _d is the accumulated delay between network translator 210 and TSN master 101 .

The integrated delay AD _d is calculated by calculating equation (d) below.
_ADd = AD' + ( _LDb * _ACDc ) (d)

In step S138, the outside communication unit 211 extracts the time TG from the additional message Follow_Up.
Time TG is the time of TSN master 101 .

Then, the time synchronization control section 213 uses the time TG and the integrated delay AD _d to calculate the synchronization time ST _e .

Synchronization time ST _e is calculated by calculating the following formula (e).
ST _e = TG + AD _d (e)

In step S139, the time synchronization control unit 213 updates the time of the network translator 210 to the synchronization time _STe to synchronize the time.

The additional message transmission (5G) will be explained based on FIG.
Send additional message (5G) is the process of sending an additional message Follow_Up from network translator 210 within 5G network 110 and is performed by network translator 210 .

In step S141, the intra-interval communication unit 215 calculates the clock deviation CD _f .
The clock deviation CD _f is the clock deviation between the 5G time source 111 and the network translator 210 .

In step S142, the clock deviation calculator 214 uses the cumulative clock deviation ACD _c and the clock deviation CD _f to calculate the clock deviation CD _g .
The clock deviation CD _g is the clock deviation between the TSN master 101 and the 5G time source 111 .

The clock deviation CD _g is calculated by calculating equation (g) below.
_CDg = _ACDc x _CDf (g)

In step S143, the intra-section communication unit 215 generates an additional message Follow_Up.

Specifically, the intra-section communication unit 215 operates as follows.
The intra-interval communication unit 215 sets the synchronous reception time TSi acquired in step S132 (see FIG. 8) in the TLV2 field of the additional message Follow_Up.
The intra-interval communication unit 215 sets the clock deviation CD _g calculated in step S142 in the TLV1 field of the additional message Follow_Up.
The intra-interval communication unit 215 sets the accumulated delay AD _d calculated in step S137 (see FIG. 8) in the Correction field of the additional message Follow_Up.

In step S<b>144 , the intra-section communication unit 215 transmits the additional message Follow_Up to the device translator 220 .

Additional message transmission (TSN) will be described based on FIGS. 10 and 11. FIG.
Send Additional Message (TSN) is the process of sending an additional message Follow_Up from device translator 220 to TSN and is performed by device translator 220 .

In step S<b>201 , the intra-section communication unit 221 receives the synchronization message Sync transmitted from the network translator 210 .

In step S202, the intra-section communication unit 221 waits for the additional message Follow_Up transmitted from the network translator 210 and receives the additional message Follow_Up.
After step S202, the process proceeds to step S203 and step S211.

In step S203, the intra-section communication unit 221 extracts information from the additional message Follow_Up.
After step S203, the process proceeds to step S221.

Specifically, the intra-section communication unit 221 operates as follows.
The intra-interval communication unit 221 extracts the synchronous reception time TSi from the TLV2 field of the additional message Follow_Up.
The intra-interval communication unit 221 extracts the clock deviation CD _g from the TVL1 field of the additional message Follow_Up.
The intra-interval communication unit 221 extracts the accumulated delay AD _d from the Correction field of the additional message Follow_Up.

In step S211, the out-of-section communication unit 224 transmits a synchronization message Sync to TSN. That is, the outside section communication unit 224 transmits the synchronization message Sync to downstream TSN devices. Specifically, the outside section communication unit 224 transmits the synchronization message Sync to the Mth bridge 122 .

In step S212, the out-of-section communication unit 224 acquires the synchronous transmission time TSe.
The synchronous transmission time TSe is the 5G time when the synchronization message Sync is transmitted.

In step S213, the delay measurement unit 222 calculates the internal delay ID _h using the synchronous transmission time TSe and the synchronous reception time TSi extracted in step S203.
Internal delay ID _h is the delay incurred in the 5G network 110 . Specifically, the internal delay ID _h is the difference between the synchronous transmission time TSe and the synchronous reception time TSi.

The internal delay ID _h is calculated by calculating equation (h) below.
ID _h = TSe-TSi (h)

In step S214, the delay measurement unit 222 calculates the integrated delay AD _k using the internal delay ID _h , the integrated delay AD _d extracted in step S203, and the clock deviation CD _g extracted in step S203.
Accumulated delay AD _k is the accumulated delay of device translator 220 and TSN master 101 .
After step S214, the process proceeds to step S223.

The integrated delay AD _k is calculated by calculating equation (k) below.
_ADk = _ADd + ( _IDh x _CDg ) (k)

In step S221, the section outside communication section 224 calculates the clock deviation CD _i .
The clock deviation CD _i is the clock deviation between the 5G time source 111 and the device translator 220 .

In step S222, the out-of-interval communication unit 224 uses the clock deviation CD _i and the clock deviation CD _g extracted in step S203 to calculate the clock deviation CD _j .
Clock deviation CD _j is the clock deviation between TSN master 101 and device translator 220 .

The clock deviation CD _j is calculated by calculating equation (j) below.
CD _j = CD _g × CD _i Formula (j)

In step S223, the out-of-section communication unit 224 generates an additional message Follow_Up.

Specifically, the outside section communication unit 224 operates as follows.
The out-of-interval communication unit 224 sets the clock deviation CD _j calculated in step S222 in the TLV1 field of the additional message Follow_Up.
The out-of-interval communication unit 224 sets the accumulated delay AD _k calculated in step S214 in the Correction field of the additional message Follow_Up.
The outside communication unit 224 deletes TLV2 of Follow_Up.

In step S224, the outside section communication unit 224 transmits the additional message Follow_Up to TSN. That is, the out-of-section communication unit 224 transmits the additional message Follow to the downstream TSN device. Specifically, the out-of-section communication unit 224 transmits the additional message Follow_Up to the Mth bridge 122 .

FIG. 12 shows the frame format of the additional message Follow_Up from network translator 210 to device translator 220 .
The header contains a Correction field.
The Correction field is set with the accumulated delay AD _d .
A clock deviation CD _g is set in the TLV1 field.
A synchronous reception time TSi is set in the TLV2 field.

FIG. 13 shows the frame format of the additional message Follow_Up from device translator 220 to TSN.
The header contains a Correction field.
An accumulated delay AD _k is set in the Correction field.
A clock deviation CD _j is set in the TLV1 field.

*** Features of Embodiment 1 ***
Features of the first embodiment will be described with reference to FIG.
Diagonal lines with arrows represent the flow of PTP messages. A specific PTP message is the additional message Follow_Up.
Time TM is the transmission time of the _PTP message in the GM.
Time TS1 is the time when _S1 is synchronized with GM.
Time TNW is the time when _NW -TT is synchronized with GM.
Time TDS is the time when _DS -TT is synchronized with GM.
Time T _SN is the time when SN is synchronized with GM.
Delay _D1 corresponds to the time from time _TM to time _TS1 . The delay D _5G corresponds to the time from time T _M to time T _DS . Delay D _N corresponds to the time from time T _M to time T _SN .

Each PTP message has a clock deviation R set in addition to the GM time.
The PTP message from GM to S1 is set with the same clock deviation R _GM (=1) as before. The clock deviation _RGM is "1".
The PTP message from S1 to NW-TT is set with the same clock deviation R _{S1_GM} as before. Clock deviation _{RS1_GM} is the clock deviation between GM and S1.
A non-conventional clock deviation R _{5G_GM} is set in the PTP message from NW-TT to DS-TT. Conventionally, a clock deviation _{RNW_GM} between GM and NW-TT was set. The clock deviation R _{NW_GM} corresponds to the cumulative clock deviation ACD _c (see step S135).
The clock deviation R _{5G_GM} is the clock deviation between GM and 5G-TS and corresponds to the clock deviation CD _g (see step S142).
Clock deviation R _{5G_GM} is expressed as follows using clock deviation R _{NW_GM} and clock deviation R _{5G_NW} . The clock deviation R _{5G_NW} is the clock deviation between 5G-TS and NW-TT, and corresponds to the clock deviation CD _f (see step S141).
R _{5G_GM} = R _{5G_NW} R _{NW_GM}
A non-conventional clock deviation R _{DS_GM} is set in the PTP message from DS-TT to SM. Conventionally, a clock deviation _{RNW_GM} was set.
The clock deviation R _{DS_GM} is the clock deviation between GM and DS-TT and corresponds to the clock deviation CD _j (see step S222).
The clock deviation R _{DS_GM} is expressed as follows using clock deviation R _{5G_GM} and clock deviation R _{DS_5G} . The clock deviation R _{DS_5G} is the clock deviation between 5G-TS and DS-TT, and corresponds to the clock deviation CD _i (see step S221).
_{RDS_GM} = _{RDS_5G} R _{5G_GM}

That is, NW-TT and DS-TT operate as follows.
The NW-TT calculates a clock deviation R _{5G_NW} from the 5G-TS, and uses the clock deviation R _{NW_5G} to calculate a clock deviation R _{5G_GM} . The NW-TT then sends the clock deviation R _{5G_GM} to the DS-TT instead of the clock deviation R _{NW_GM} .
The DS-TT calculates the clock deviation R _{DS_5G} from the 5G-TS, and calculates the clock deviation R _{DS_GM} using the clock deviation R _{DS_5G} and the clock deviation R _{5G_GM} . DS-TT then sends clock deviation _{R_DS_GM} to SN instead of clock deviation _{R_NW_GM} .

The previous method according to 3GPP 23.501 assumed that the 5G_TS and NW-TT clock deviations and the NW-TT and DS-TT clock deviations were zero. Therefore, the final time synchronization accuracy is poor.
In the method of Embodiment 1, the clock deviation between 5G_TS and NW-TT and the clock deviation between NW-TT and DS-TT are considered.

*** Effect of Embodiment 1 ***
According to Embodiment 1, it is possible to eliminate the time error caused by a 5G network that originally does not exist in the TSN network joining the TSN network, that is, the time error caused by the clock deviation between network devices.
Specifically, each of the network translator 210 and the device translator 220 uses the clock deviation (CD _f , CD _i ) with the 5G time source 111 to calculate the clock deviation between the network translator 210 and the device translator 220. Calculate indirectly. This makes it possible to eliminate the synchronization time error of the TSN slave 121 .

Embodiment 1 is advantageous in terms of cost because it eliminates the need to add control messages by changing existing time synchronization messages.

*** Supplement to the embodiment ***
Based on FIG. 15, the hardware configuration of the translator 300 is supplemented.
Translator 300 comprises processing circuitry 309 .
The processing circuit 309 is hardware that implements functional configuration elements of the network translator 210 or the device translator 220 .
The processing circuitry 309 may be dedicated hardware or may be a processor 311 that executes programs stored in memory.

If processing circuitry 309 is dedicated hardware, processing circuitry 309 may be, for example, a single circuit, multiple circuits, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.
ASIC is an abbreviation for Application Specific Integrated Circuit.
FPGA is an abbreviation for Field Programmable Gate Array.

The translator 300 may include a plurality of processing circuits that substitute for the processing circuit 309.

In the processing circuit 309, some functions may be implemented by dedicated hardware, and the remaining functions may be implemented by software or firmware.

In this way, the functions of translator 300 can be implemented in hardware, software, firmware, or a combination thereof.

Each embodiment is an example of a preferred form and is not intended to limit the technical scope of the present disclosure. Each embodiment may be implemented partially or in combination with other embodiments. The procedures described using flowcharts and the like may be changed as appropriate.

The "unit" that is an element of the network translator 210 or the device translator 220 may be read as "processing", "process", "circuit" or "circuitry".

100 time synchronization network system, 101 TSN master, 102 first bridge, 110 5G network, 111 5G time source, 121 TSN slave, 122 M bridge, 210 network translator, 211 outside section communication unit, 212 delay measurement unit, 213 time Synchronization control unit 214 Clock deviation calculation unit 215 Intra-section communication unit 220 Device translator 221 In-section communication unit 222 Delay measurement unit 223 Clock deviation calculation unit 224 Out-of-section communication unit 300 Translator 301 Computer 309 Processing circuit, 310 motherboard, 311 processor, 312 serial communication device, 313 translator circuit, 320 expansion card, 321 port, 322 port.

Claims

A network translator used in a mobile communication system provided between an upstream of a time synchronization network system and a downstream of the time synchronization network system,
The upstream of the time synchronization network system has a master that is a device serving as a time source of the time synchronization network system,
The mobile communication system has a time server serving as a time source for the mobile communication system and a device translator,
The device translator calculates the clock deviation between the master and the device translator using the clock deviation between the master and the time server and the clock deviation between the time server and the device translator, and the calculated clock deviation A translator that generates a message by setting and transmits the generated message downstream of the time synchronization network system,
The network translator is
a clock deviation calculation unit that calculates the clock deviation between the master and the time server;
an intra-section communication unit that sets the clock deviation between the master and the time server to generate a message and transmits the generated message to the device translator;
A network translator with
The network translator is
a delay measuring unit that calculates a clock deviation between the master and the network translator;
An intra-section communication unit that calculates the clock deviation of the network translator and the time server,
The clock deviation calculating unit calculates the clock deviation between the master and the time server using the clock deviation between the master and the network translator and the clock deviation between the network translator and the time server. Item 1. The network translator according to Item 1.
3. The message according to claim 1 or 2, wherein each of the message from the network translator to the device translator and the message from the device translator to the downstream of the time synchronization network system is an additional message of Precision Time Protocol. network translator.
A device translator used in a mobile communication system provided between an upstream of a time synchronization network system and a downstream of the time synchronization network system,
The upstream of the time synchronization network system has a master that is a device serving as a time source of the time synchronization network system,
The mobile communication system has a time server serving as a time source for the mobile communication system and a network translator,
The network translator calculates the clock deviation between the master and the time server using the clock deviation between the master and the network translator and the clock deviation between the network translator and the time server, and calculates the calculated clock deviation. is a translator that configures and generates messages and sends the generated messages,
The device translator is
an intra-section communication unit that receives the message from the network translator and extracts the clock deviation between the master and the time server from the received message;
a clock deviation calculation unit that calculates the clock deviation between the master and the device translator using the clock deviation between the master and the time server;
an out-of-section communication unit that sets the clock deviation between the master and the device translator to generate a message and transmits the generated message downstream of the time synchronization network system;
A device translator with
The outside communication unit calculates the clock deviation between the time server and the device translator, and uses the clock deviation between the master and the time server and the clock deviation between the time server and the device translator, 5. The device translator of claim 4, wherein the clock deviation between the master and the device translator is calculated.
6. The message according to claim 4 or 5, wherein each of said message from said network translator to said device translator and said message from said device translator to said time synchronization network system downstream is an additional message of Precision Time Protocol. device translator.