KR20230121934A - Network translator and device translator - Google Patents

Abstract

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

Description

Network translator and device translator

The present disclosure relates to a 5G-TSN translator considering clock deviation.

In the multi-stage wired TSN time synchronization method, 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 of each upstream section and the integrated value of the clock deviation of each upstream section. This realizes high-precision time synchronization.

TSN is an abbreviation for Time-Sensitive Networking.

The 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 a first-stage virtual device. However, physically, in the 5G section, a device network translator (NW-TT) is placed on one side across the radio section, and a device translator (DS-TT) is placed on the other side across the radio section. do.

A translator is a device having a wired TSN function, and is also referred to as a TSN translator.

In 5G networks, delays are different in uplink communication and downlink communication. Therefore, even if a delay measurement message is exchanged between 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 devices in the 5G section are synchronized at a time (5G time) independent of the TSN time, and link delay in the 5G section is reduced by timestamping of the 5G time. Measure.

Non-Patent Document 1 discloses a conventional 5G-TSN network.

In the conventional 5G-TSN network, it is assumed that each clock deviation of the NW-TT and DS-TT for the GrandMaster (GM) of the 5G network is zero. In addition, the DS-TT includes the clock deviation of the NW-TT with respect to the TSN GM in the time transfer message Sync/Follow_Up and sends the time transfer message to the downstream TSN slave.

[Non-Patent Document 1] 3GPP TS 23.501 V16.4.0 (2020-03) “3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System architecture for the 5G System (5GS); Stage 2 (Release 16)”

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

An object of the present disclosure is to suppress a synchronization time error in a TSN slave downstream of DS-TT by considering a clock deviation in 5G-TSN.

The network translator of the present disclosure is used in a mobile communication system provided between an upstream of a time-synchronous network system and a downstream of the time-synchronous network system.

An 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 of 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 A translator that generates a message by setting a deviation and transmits the generated message downstream of the time synchronization network system.

The network translator,

a clock deviation calculator configured to calculate the clock deviation between the master and the time server;

and an intra-interval communication unit configured to set the clock deviation between the master and the time server to generate a message and transmit the generated message to the device translator.

According to the present disclosure, it is possible to suppress a synchronization time error in a TSN slave downstream of DS-TT by considering a clock deviation in 5G-TSN.

1 is a configuration diagram of a time synchronization network system 100 in Embodiment 1;
Fig. 2 is a hardware configuration diagram of a translator 300 in Embodiment 1;
Fig. 3 is a functional configuration diagram of network translator 210 in Embodiment 1;
Fig. 4 is a functional configuration diagram of the device translator 220 in Embodiment 1;
5 is a flowchart of clock deviation calculation in Embodiment 1;
Fig. 6 is a diagram showing the relationship between clock deviation R _{NW_GM} (= CD _a ) and each time in Embodiment 1;
Fig. 7 is a flowchart of link delay calculation in Embodiment 1;
8 is a flowchart of time alignment in Embodiment 1;
9 is a flowchart of additional message transmission (5G) in Embodiment 1;
Fig. 10 is a flowchart of additional message transmission (TSN) in Embodiment 1;
Fig. 11 is a flowchart of additional message transmission (TSN) in Embodiment 1;
Fig. 12 is a table showing the frame format of the additional message Follow_Up (NW-TT→DS-TT) in Embodiment 1;
Fig. 13 is a table showing the frame format of the additional message Follow_Up (DS-TT→TSN) in Embodiment 1;
Fig. 14 is a diagram showing clock deviation R set for each PTP message in Embodiment 1;
Fig. 15 is a supplementary diagram of the hardware configuration of translator 300 in Embodiment 1;

In the embodiments and drawings, the same reference numerals are assigned to the same elements or corresponding elements. Descriptions of elements having the same reference numerals as those described are appropriately omitted or simplified. Arrows in the figure mainly indicate the flow of data or flow of processing.

Embodiment 1.

The time synchronization network system 100 will be described based on FIGS. 1 to 13 .

The 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 synchronization 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 a fifth generation mobile communication system. The fifth generation mobile communication system is an example of a mobile communication system.

TSN is a time-synchronized network system called time-sensitive networking.

***Description of configuration***

Based on FIG. 1, the structure of the time synchronization network system 100 is demonstrated.

A 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 devices.

The TSN master 101 is a network device serving as a time source in TSN, and is called a grand master (GM). The side where the TSN master 101 is located is called "upstream".

The TSN slave 121 is a network device 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 described as "GM".

The TSN slave 121 is described as "SLAVE".

The first bridge 102 is the first bridge counted from the TSN master 101 in 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 in the communication path from the TSN master 101 to the TSN slave 121.

The first bridge 102 is disposed upstream with respect to the 5G network 110 , and the Mth bridge 122 is disposed downstream with respect to the 5G network 110 .

The first bridge 102 is described as "S1".

The Mth bridge 122 is described 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 network devices of the 5G network 110 .

The 5G time source 111 is a network device serving as a time source of the 5G network 110, and is called a time server (TS).

The 5G time source 111 is described as "5G-TS".

The view of the 5G network 110 is independent from the view of the TSN.

The network translator 210 is a translator that performs connection between networks of 5G-TSN, has a TSN time synchronization function, and is disposed upstream in the 5G network 110.

The device translator 220 is a translator that performs a 5G-TSN network connection, has a TSN time synchronization function, and is disposed on the downstream side of the 5G network 110.

Network translator 210 and device translator 220 are also referred to as TSN translators (TT).

The network translator 210 is described as "NW-TT".

The device translator 220 is described as "DS-TT".

Based on Fig. 2, the hardware configuration of the translator 300 will be described.

The translator 300 is a generic term for the network translator 210 and the device translator 220.

The translator 300 includes a main board 310 and an expansion card 320 .

The main board 310 is connected to the control computer 301.

The main board 310 includes a processor 311, a serial communication device 312, and a translator circuit 313. These are connected to each other via a bus. This bus is also referred to as a data bus, and performs a connection for performing register access (setting, reading) from the processor 311.

The processor 311 is an electronic circuit that performs arithmetic processing, and includes a logic circuit, a primary cache, and the like.

The serial communication device 312 is a device for performing serial communication. Specifically, the 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 functions of the translator are built with programmable logic. FPGA is an abbreviation for Field-Programmable Gate Array.

The expansion card 320 is also called a mezzanine card or a daughter card, and is connected to the main board 310 . Specifically, the expansion card 320 is connected to a dedicated connector installed on the main board 310 .

The expansion card 320 includes a port 321 and a port 322 .

Port 321 is a port connected to TSN, and port 322 is a port connected to 5G. Specifically, ports 321 and 322 are ports called SFPs. 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-interval communication unit 211, a delay measurement unit 212, a time synchronization control unit 213, a clock deviation calculation unit 214, and an intra-interval communication unit 215.

These elements are realized by the translator circuit 313.

The out-of-section communication unit 211 performs transmission and reception with TSN. In addition, the out-of-section communication unit 211 receives and analyzes the frame, extracts a header and message from the received PTP frame, and terminates the frame. Further, the out-of-section communication unit 211 performs an error check and length measurement, and discards the error frame.

In addition, the out-of-interval communication unit 211 notifies the delay measurement unit 212 of the transmission/reception time of the PTP frame. Therefore, the out-of-section communication unit 211 maintains the 5G time (TSi) when the network translator 210 receives the Sync message.

PTP is an abbreviation for Precision Time Protocol.

Delay measurement unit 212 uses a two-step peer-to-peer (P2P) pass delay algorithm called Pdelay_Req, Pdelay_Resp, and Pdelay_Resp_Follow_Up, and delay time and clock deviation between adjacent TSN devices used for time synchronization. to measure The clock deviation is calculated based on the time difference of the P2P delay measurement message.

The delay measurement unit 212 generates state information related to transmission/reception control of PTP messages (Pdelay_Req, Pdelay_Resp, Pdelay_Resp_Follow_Up) and a delay measurement function.

A PTP message is a message specified in IEEE 802.1 AS.

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

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

The clock deviation calculation unit 214 uses the clock deviation between its own device and the GM calculated by the delay measurement unit 212 and the clock deviation between its own device and the 5G time source calculated by the intra-interval communication unit 215. Then, the clock deviation between the 5G time source and GM is calculated.

The interval communication unit 215 provides time synchronized with the 5G time source 111 . In addition, the intra-interval communication unit 215 calculates a clock deviation between its own device and the 5G time source.

In addition, the intra-interval communication unit 215 calculates 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 Add to the TLV1 area of the Follow_Up message and transmit the Follow_Up message to 5G.

In addition, the function of each element will be described later.

Based on Fig. 4, the functional configuration of the device translator 220 will be described.

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 out-of-interval communication unit 224.

These elements are realized by the translator circuit 313.

Intersection communication unit 221 transmits and receives 5G. In addition, the intra-interval communication unit 221 calculates the 5G time (TSi) when the network translator 210 receives the Sync message from the TLV1 area of the received Follow_Up message and the GM and 5G calculated by the network translator 210 Information called the cumulative clock deviation of the time source is extracted, and the extracted information is transmitted to the delay measuring unit 222.

The delay measurement unit 222 receives the 5G time (TSe) at the time of transmission of the Sync message from the out-of-zone communication unit 224 .

The delay measurement unit 222 uses the TSi received from the intra-interval communication unit 221, the accumulated clock deviation between the GM and the 5G time source received from the intra-intersection communication unit 221, and the TSe received from the out-of-intersection communication unit 224. to calculate the delay time inside 5G. And, the delay measuring unit 222 transmits the delay time inside 5G to the out-of-interval communication unit 224.

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

The out-of-section communication unit 224 performs transmission and reception with downstream TSN devices. Further, the out-of-section communication unit 224 receives and analyzes the PTP frame, extracts a header and message from the received PTP frame, and terminates the message. Further, the out-of-section communication unit 224 performs an error check and length measurement, and discards the error frame. In addition, the out-of-interval communication unit 224 notifies the delay measurement unit 222 of the 5G time (TSe) at the time of transmission of the Sync message.

The out-of-interval communication unit 224 adds the 5G internal delay time calculated by the delay measurement unit 222 to a correction field of the Follow_Up message. In addition, the out-of-interval communication unit 224 rewrites the TLV of the Follow_Up message into the clock difference 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 the downstream TSN device.

In addition, the out-of-interval communication unit 224 calculates the clock difference between its own device and the 5G time source and transmits it to the clock difference calculation unit 223.

In addition, the function of each element will be described later.

***Description of action***

The sequence of operations of the time synchronization network system 100 corresponds to the time synchronization method.

Based on Fig. 5, clock deviation calculation will be explained.

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.

A TSN device is a TSN network device.

The adjacent TSN device is specifically the first bridge 102 .

In step S111, the out-of-section communication unit 211 receives the first delay measurement response message Pdelay_Resp from the neighboring TSN device.

The delay measurement response message Pdelay_Resp is a response to the delay measurement request message Pdelay_Req.

In step S112, the out-of-section communication unit 211 acquires the first response reception time t _n .

The first response reception time t _n is the reception time of the first delay measurement response message Pdelay_Resp.

For example, the time of the translator 300 is acquired from the local operating system (OS).

In step S113, the out-of-section 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 out-of-section communication unit 211 waits for the N-th delay measurement response message Pdelay_Resp and receives the N-th delay measurement response message Pdelay_Resp. "N" is an integer greater than or equal to 2.

In step S115, the out-of-section communication unit 211 acquires the Nth response reception time t _nn (PdelayRespEventIngressTimestamp).

The Nth response reception time t _nn is the reception time of the Nth delay measurement response message Pdelay_Resp.

In step S116, the out-of-section communication unit 211 extracts the N-th request reception time t' _nn from the payload of the N-th delay measurement response message Pdelay_Resp_Follow_Up.

The Nth 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 measuring unit 212 uses the first response reception time t _n , the first response transmission time t' n, the Nth response reception time t _{nn and} the Nth response transmission time t' _nn , Calculate the clock deviation CD _a .

Clock deviation CD _a is the clock deviation between network translator 210 and an adjacent TSN device.

Clock deviation CD _a is calculated by calculating the following formula (a).

CD _a = (t _{nn -} t _n )/(t' _{nn -} t' _n ) (a)

Based on FIG. 6, the relationship between clock deviation R _{NW_GM} and each time is demonstrated. Clock deviation R _{NW_GM} corresponds to clock deviation CD _a .

NW-TT transmits the delay measurement request message Pdelay_Req. The transmission time is time t ₁ .

The GM receives the delay measurement request message Pdelay_Req. The reception time is time t ₂ .

The GM transmits the first delay measurement response message Pdelay_Resp. The transmission time is time t'n.

NW-TT receives the first delay measurement response message Pdelay_Resp. The reception time is time t _n .

GM transmits the Nth delay measurement response message Pdelay_Resp. The transmission time is time t' _nn .

NW-TT receives the Nth delay measurement response message Pdelay_Resp. The reception time is time t _nn .

The clock deviation R _{NW_GM} is calculated by calculating the above equation (a).

Based on Fig. 7, link delay calculation will be explained.

The 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 time of transmission delay.

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

In step S122, the out-of-section communication unit 211 acquires the request transmission time t ₁ .

The request transmission time t ₁ 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 neighboring TSN device and receives the delay measurement response message Pdelay_Resp.

In step S124, the out-of-section communication unit 211 acquires the response reception time t ₄ .

The response reception time t ₄ is the reception time of the delay measurement response message Pdelay_Resp.

In step S125, the out-of-section communication unit 211 extracts the request reception time t ₂ from the payload of the delay measurement response message Pdelay_Resp.

The request reception time t ₂ 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-section 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-section communication unit 211 extracts the response transmission time t ₃ from the payload of the additional message Pdelay_Resp_Follow_Up.

The response transmission time t ₃ 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 S128, delay measuring unit 212 calculates link delay _LDb using clock deviation CD _a , request transmission time t ₁ , response reception time t ₄ , request reception time t ₂ and response transmission time t ₃ . yield

Link delay LD _b is a link delay between network translator 210 and an adjacent TSN device.

The link delay LD _b is calculated by calculating the following formula (b).

LD _b = (CD _a × (t ₄ -t ₁ )-(t ₂ -t ₃ ))/2 (b)

Based on FIG. 8, time alignment is demonstrated.

Time alignment is processing to align 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 a synchronization message Sync from an adjacent TSN device.

In step S132, the out-of-section communication unit 211 acquires the synchronization reception time TSi.

The synchronization reception time TSi is the 5G time at the reception of the synchronization message Sync.

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

In step S134, the out-of-section communication unit 211 extracts the accumulated clock deviation ACD' from the additional message Follow_Up.

Accumulated clock deviation ACD' is the accumulated clock deviation between the adjacent TSN device of network translator 210 and TSN master 101.

In step S135, the delay measuring unit 212 calculates the accumulated clock deviation ACD c using the clock deviation CD _a and the accumulated clock deviation _ACD '.

Accumulated clock deviation ACD _c is the accumulated clock deviation between network translator 210 and TSN master 101.

Cumulative clock deviation ACD _c is calculated by calculating the following equation (c).

ACD _c = ACD'×CD _a (c)

In step S136, the out-of-section communication unit 211 extracts the accumulated delay value AD' from the correction field of the additional message Follow_Up.

The integrated delay value AD' is an integrated delay value between the adjacent TSN devices of the network translator 210 and the TSN master 101.

In step S137, the delay measurement unit ₂₁₂ calculates the integrated delay ADd using the integrated delay value AD', the link delay _LDb and the accumulated clock deviation _ACDc .

The integrated delay AD _d is the integrated delay between the network translator 210 and the TSN master 101.

Integration delay AD _d is calculated by calculating the following formula (d).

AD _d = AD' + (LD _b *ACD _c ) (d)

In step S138, the out-of-section communication unit 211 extracts the time TG from the additional message Follow_Up.

Time TG is the time of the TSN master 101.

And the time synchronization control part 213 calculates synchronization time _STe using time TG and accumulated delay _ADd .

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 ST _e to perform time alignment.

Based on Fig. 9, additional message transmission (5G) will be described.

The additional message transmission (5G) is a process of transmitting an additional message Follow_Up from the network translator 210 within the 5G network 110, and is executed by the network translator 210.

In step S141, the intra-interval communication unit 215 calculates the clock deviation CD _f .

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 calculation unit 214 calculates the clock deviation CDg using the cumulative clock deviation _ACDc and _the clock deviation _CDf .

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 the following equation (g).

CD _g = ACD _c × CD _f (g)

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

Specifically, the intra-interval communication unit 215 operates as follows.

The intra-interval communication unit 215 sets the synchronous reception time TSi obtained 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 integrated delay AD _d calculated in step S137 (see Fig. 8) in the correction field of the additional message Follow_Up.

In step S144, the intra-section communication unit 215 transmits an additional message Follow_Up to the device translator 220.

Based on Figs. 10 and 11, additional message transmission (TSN) will be described.

The additional message transmission (TSN) is a process of transmitting an additional message Follow_Up from the device translator 220 to the TSN, and is executed by the device translator 220.

In step S201, the intra-interval 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, processing proceeds to steps S203 and 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-interval communication unit 221 operates as follows.

The intersection communication unit 221 extracts the synchronization 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 intersection communication unit 221 extracts the integration delay AD _d from the correction field of the additional message Follow_Up.

In step S211, the out-of-interval communication unit 224 transmits the synchronization message Sync to the TSN. That is, the out-of-interval communication unit 224 transmits the synchronization message Sync to the downstream TSN device. Specifically, the out-of-interval communication unit 224 transmits the synchronization message Sync to the M-th bridge 122 .

In step S212, the out-of-interval communication unit 224 acquires the synchronous transmission time TSe.

The synchronization transmission time TSe is the 5G time at the time of transmission of the synchronization message Sync.

In step S213, the delay measurement part 222 calculates 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 a delay occurring 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 the following formula (h).

ID _h = TSe-TSi (h)

In step S214, the delay measurement unit 222 calculates the integrated delay ADk _using the internal delay ID _h , the integrated delay _ADd extracted in step S203, and the clock deviation _CDg extracted in step S203.

The integrated delay AD _k is the integrated delay between the device translator 220 and the TSN master 101.

After step S214, the process proceeds to step S223.

Integration delay AD _k is calculated by calculating the following formula (k).

AD _k = AD _d + (ID _h × CD _g ) (k)

In step S221, the out-of-interval communication unit 224 calculates the clock deviation _CDi .

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 calculates clock deviation _CDj using the clock deviation _CDi and the clock deviation _CDg extracted in step S203.

Clock deviation CD _j is the clock deviation between the TSN master 101 and the device translator 220.

The clock deviation CD _j is calculated by calculating the following equation (j).

CD _j = CD _g × CD _i Equation (j)

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

Specifically, the out-of-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-section communication unit 224 sets the integration delay AD _k calculated in step S214 in the correction field of the additional message Follow_Up.

The out-of-section communication unit 224 deletes TLV2 of Follow_Up.

In step S224, the out-of-section communication unit 224 transmits an 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 .

In Fig. 12, the frame format of the additional message Follow_Up from the network translator 210 to the device translator 220 is shown.

The header contains correction fields.

In the correction field, the integration delay AD _d is set.

In the TLV1 field, the clock deviation CD _g is set.

Synchronous reception time TSi is set in the TLV2 field.

In Fig. 13, the frame format of the additional message Follow_Up from the Device Translator 220 to the TSN is shown.

The header contains correction fields.

In the correction field, the integration delay AD _k is set.

In the TLV1 field, the clock deviation CD _j is set.

***Features of Embodiment 1***

Based on FIG. 14, the characteristics of Embodiment 1 are demonstrated.

The slanted line with an arrow indicates the flow of PTP messages. A specific PTP message is the additional message Follow_Up.

Time T _M is the transmission time of the PTP message in the GM.

Time T _S1 is the time when S1 synchronizes with GM.

Time T _NW is the time at which NW-TT synchronizes with GM.

Time T _DS is the time at which DS-TT synchronizes with GM.

Time T _SN is the time when SN synchronizes with GM.

Delay D ₁ corresponds to the time from time T _M to time T _S1 . Delay D _5G corresponds to the time from time T _M to time T _DS . Delay _DN corresponds to the time from time T _M to time T _SN .

In each PTP message, a clock deviation R is set in addition to the GM time.

In the PTP message from GM to S1, the same clock deviation R _GM (=1) as before is set. Clock deviation R _GM is “1”.

In the PTP message from S1 to NW-TT, the same clock deviation R _{S1_GM} as before is set. Clock deviation R _{S1_GM} is the clock deviation between GM and S1.

In the PTP message from NW-TT to DS-TT, a clock deviation R _{5G_GM} different from the conventional one is set. Conventionally, the clock deviation R _{NW_GM} between GM and NW-TT was set. The clock deviation R _{NW_GM} corresponds to the cumulative clock deviation ACD _c (refer to step S135).

Clock deviation R _{5G_GM} is the clock deviation between GM and 5G-TS, and corresponds to clock deviation CD _g (refer to step S142).

Clock deviation R _{5G_GM} is expressed as follows using clock deviation R _{NW_GM} and clock deviation R _{5G_NW} . Clock deviation R _{5G_NW} is the clock deviation between 5G-TS and NW-TT, and corresponds to clock deviation CD _f (refer to step S141).

R _{5G_GM} = R _{5G_NW} R _{NW_GM}

In the PTP message from DS-TT to SM, a clock deviation R _{DS_GM} different from the conventional one is set. Conventionally, clock deviation R _{NW_GM} was set.

Clock deviation R _{DS_GM} is the clock deviation between GM and DS-TT, and corresponds to clock deviation CD _j (refer to step S222).

Clock deviation R _{DS_GM} is expressed as follows using clock deviation R _{5G_GM} and clock deviation R _{DS_5G} . Clock deviation R _{DS_5G} is the clock deviation between 5G-TS and DS-TT, and corresponds to clock deviation CD _i (refer to step S221).

R _{DS_GM} = R _{DS_5G} R _{5G_GM}

That is, NW-TT and DS-TT operate as follows.

NW-TT calculates clock deviation R _{5G_NW} from 5G-TS, and calculates clock deviation R _{5G_GM} using clock deviation R _{NW_5G} . And, NW-TT sends clock deviation R _{5G_GM} to DS-TT instead of clock deviation R _{NW_GM} .

DS-TT calculates clock deviation R _{DS_5G} from 5G-TS, and calculates clock deviation R DS_GM using clock _deviation R _{DS_5G} and clock deviation R _{5G_GM} . And, DS-TT sends clock deviation R _{DS_GM} to SN instead of clock deviation R _{NW_GM} .

In the conventional method according to 3GPP23.501, it is assumed that the clock deviation between 5G_TS and NW-TT and between NW-TT and DS-TT is 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, a time error caused by a 5G network that does not originally exist in the TSN network joining the TSN network, that is, a time error caused by clock deviation between network devices can be eliminated.

Specifically, each of the network translator 210 and the device translator 220 uses clock deviations (CD _f , CD _i ) from the 5G time source 111 to transmit the network translator 210 and the device translator 210 to each other. The clock deviation between translators 220 is indirectly calculated. This makes it possible to eliminate the synchronization time error of the TSN slave 121.

Embodiment 1 is superior in terms of cost because the addition of a control message becomes unnecessary by changing the existing time synchronization message.

***Supplement of the embodiment***

Based on Fig. 15, the hardware configuration of the translator 300 is supplemented.

Translator 300 includes processing circuitry 309 .

The processing circuit 309 is hardware that realizes elements of the functional configuration of the network translator 210 or the device translator 220.

The processing circuit 309 may be dedicated hardware or may be a processor 311 that executes a program stored in memory.

When the processing circuit 309 is dedicated hardware, the processing circuit 309 is, for example, a single circuit, a complex circuit, 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 replacing 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.

As such, the functions of the translator 300 may be realized in hardware, software, firmware or a combination thereof.

Each embodiment is an illustration of a preferred embodiment, and is not intended to limit the technical scope of the present disclosure. Each embodiment may be implemented partially or may be implemented in combination with other embodiments. You may change the procedure demonstrated using a flowchart etc. suitably.

"Part" which is an element of the network translator 210 or the device translator 220 may be read interchangeably with "process", "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 out-of-zone communication unit, 212 delay measurement unit, 213 time 214 Clock deviation calculation unit, 215 intra-interval communication unit, 220 device translator, 221 intra-interval communication unit, 222 delay measurement unit, 223 clock deviation calculation unit, 224 out-of-interval communication unit, 300 translator, 301 computer, 309 processing circuit , 310 main board, 311 processor, 312 serial communication device, 313 translator circuit, 320 expansion card, 321 port, 322 port.

Claims (6)

A network translator used in a mobile communication system provided between an upstream of a time synchronous network system and a downstream of the time synchronous network system,
An 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 includes a time server serving as a time source of 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 A translator that generates a message by setting a deviation and transmits the generated message downstream of the time synchronization network system;
The network translator,
a clock deviation calculator configured to calculate the clock deviation between the master and the time server;
Intersection communication unit generating a message by setting the clock deviation between the master and the time server and transmitting the generated message to the device translator.
Network translator comprising a. According to claim 1,
The network translator,
a delay measurement unit for calculating a clock deviation between the master and the network translator;
an intra-interval communication unit for calculating a clock deviation between the network translator and the time server;
The clock deviation calculator 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.
network translator. According to claim 1 or 2,
Each of the messages from the network translator to the device translator and the message from the device translator downstream of the time synchronous network system is an additional message of Precision Time Protocol (PTP).
network translator. A device translator used in a mobile communication system provided between an upstream of a time synchronous network system and a downstream of the time synchronous network system,
An 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 includes a time server serving as a time source of 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 the calculated clock deviation It is a translator that creates a message by setting and transmits the generated message,
The device translator,
an intra-interval communication unit for receiving the message from the network translator and extracting the clock deviation between the master and the time server from the received message;
a clock deviation calculator configured to calculate a clock deviation between the master and the device translator by using the clock deviation between the master and the time server;
An out-of-section communication unit configured to set the clock deviation between the master and the device translator to generate a message and transmit the generated message downstream of the time synchronization network system.
A device translator comprising a. According to claim 4,
The out-of-section communication unit calculates a 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, Calculating the clock deviation of the master and the device translator
device translator. According to claim 4 or 5,
Each of the messages from the network translator to the device translator and the message from the device translator downstream of the time synchronous network system is an additional message of Precision Time Protocol (PTP).
device translator.

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