Signal delay accurate measurement and synchronization method for complex communication environment

Abstract

The invention discloses a signal delay accurate measurement and synchronization method for a complex communication environment. The method comprises the following steps: generating a unique equipment ID; calculating a clock skew therebetween; the transmission delay is measured through multiple round-trip communication between the devices, and the measurement frequency is dynamically adjusted according to the delay change; dynamically adjusting a local clock by the equipment, and performing delay compensation; dynamically adjusting delay measurement and a synchronization strategy according to environment change; a distributed coordination algorithm is adopted, so that all devices are kept synchronous; timestamp signature and message authentication are adopted, so that time synchronization is prevented from being attacked or interfered. Signal delay is measured in real time through multiple round-trip communication, the measurement frequency is dynamically adjusted according to the delay change, high-precision synchronization is kept in a dynamic environment, meanwhile, when clock skew is calculated, dynamic delay is taken into consideration, a local clock is adjusted through a delay compensation algorithm, and synchronization errors are reduced.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a signal delay accurate measurement and synchronization method for complex communication environments. Background Art

[0002] In modern wireless communication systems, time synchronization is a key technology to ensure the collaboration between devices. For example, in the Industrial Internet of Things, sensors, controllers, and actuators require precise time synchronization to achieve efficient data collection and control; in intelligent transportation systems, communication between vehicles and infrastructure requires high-precision time synchronization to ensure safety and efficiency. However, factors such as signal delay, clock deviation, and dynamic interference in complex communication environments pose great challenges to time synchronization.

[0003] In the existing technology, the synchronization methods based on the Network Time Protocol (NTP) and the IEEE 1588 Precision Time Protocol (PTP) can achieve high-precision time synchronization in an ideal communication environment, but there is a key problem in complex communication environments: they cannot effectively handle dynamically changing signal delays. Specifically, existing methods usually assume that signal delays are fixed or change slowly, but in actual complex environments, signal delays can change dynamically due to factors such as network congestion, signal interference, or device movement.

[0004] Due to the dynamic changes in signal delays, existing methods are unable to adjust synchronization strategies in real time, resulting in a gradual increase in the time synchronization error between devices. Under the influence of dynamic delays, the synchronization status between devices may fluctuate frequently, affecting the overall stability and reliability of the system. In order to cope with dynamic delays, time synchronization operations need to be performed frequently, which increases communication overhead and computing resource consumption. Summary of the invention

[0005] The purpose of the present invention is to provide a method for accurately measuring and synchronizing signal delay in a complex communication environment to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for accurately measuring and synchronizing signal delay in a complex communication environment comprises the following steps:

[0008] Step S1, distributed clock initialization, all devices are initialized through local clocks and record initial timestamps to generate unique device IDs;

[0009] Step S2, clock deviation calculation, the devices exchange timestamp information through wireless communication and calculate the clock deviation between each other;

[0010] Step S3, adaptive delay measurement, measuring the transmission delay between devices through multiple round-trip communications, and dynamically adjusting the measurement frequency according to the delay change;

[0011] Step S4, delay compensation and synchronization, according to the measured transmission delay and clock deviation, the device dynamically adjusts the local clock to perform delay compensation;

[0012] Step S5, dynamic environment monitoring and adjustment, the system continuously monitors changes in the communication environment and dynamically adjusts delay measurement and synchronization strategies according to environmental changes;

[0013] Step S6, multi-device expansion and coordination, using a distributed coordination algorithm to keep all devices synchronized;

[0014] Step S7, security and fault-tolerance mechanism, uses timestamp signature and message authentication to prevent time synchronization from being attacked or interfered with, and has a fault-tolerance mechanism to keep other devices synchronized when some devices fail or communication is interrupted.

[0015] In the present invention, in step S1, the timestamp recorded when the device is initialized includes the initial value of the local clock and the device ID, which is used for subsequent clock deviation calculation and synchronization.

[0016] In the present invention, in step S2, the steps of calculating the clock deviation are as follows:

[0017] Step S201, device A sends a message containing a local timestamp to device B;

[0018] Step S202, device B records the receiving timestamp and calculates the clock deviation with device A;

[0019] Step S203: Device B returns the calculation result to device A, and device A adjusts the local clock according to the returned result.

[0020] The clock deviation calculation uses the clock deviation formula, which is as follows:

[0021] Δt AB =t B_recv -t A_send

[0022] Among them, Δt AB is the clock deviation between device A and device B, t B_recv is the timestamp when device B receives the message sent by device A, t A_send It is the timestamp when device A sends the message.

[0023] In the present invention, in step S3, the steps of adaptive delay measurement are as follows:

[0024] Step S301, the devices communicate back and forth multiple times, and record the send and receive timestamps for each communication;

[0025] Step S302, calculate the average transmission delay, and dynamically adjust the measurement frequency according to the delay change;

[0026] Step S303, in the case of a large delay change, increase the measurement frequency to improve the measurement accuracy;

[0027] The adaptive delay measurement uses the average delay formula, which is specifically as follows:

[0028]

[0029] where Delay avg is the average transmission delay, t B_recv_i is the timestamp when device B receives the message in the i-th communication, t A_send_i is the timestamp when device A sends the message in the i-th communication, and n is the number of communications

[0030] __.

[0031] In the present invention, in step S4, the steps of delay compensation and synchronization are as follows:

[0032] Step S401, according to the measured transmission delay and clock deviation, the device calculates the synchronization time;

[0033] Step S402, the device adjusts the local clock and synchronizes with the master device or other devices;

[0034] Step S403, before each acquisition task starts, perform a delay compensation to ensure the synchronization of data acquisition;

[0035] The delay compensation and synchronization use the synchronization time formula, which is specifically as follows:

[0036] t sync = t local + Δt AB + Delay avg

[0037] where t sync is the synchronized time, t local is the local clock time, Δt AB is the clock deviation between device A and device B, and Delay avg is the average transmission delay.

[0038] In the present invention, in step S5, the steps of dynamic environment monitoring and adjustment are as follows:

[0039] Step S501, the system monitors the changes in the communication environment in real time, including signal strength, interference level, and device location changes;

[0040] Step S502, dynamically adjust the delay measurement and synchronization strategy according to the environmental changes. In the case of large signal interference, increase the delay measurement frequency or adopt a more robust synchronization algorithm;

[0041] The dynamic environment monitoring and adjustment uses an adaptive frequency adjustment formula, which is as follows:

[0042]

[0043] where f measure is the adjusted measurement frequency, f base is the basic measurement frequency, ΔDelay is the delay change amount, and Delay threshold is the delay change threshold.

[0044] In the present invention, in step S6, the steps of multi-device expansion and coordination are as follows:

[0045] Step S601, adopt a distributed coordination algorithm to keep all devices synchronized;

[0046] Step S602, each device calculates the global synchronization time according to the communication results with other devices and adjusts the local clock;

[0047] Step S602, in a multi-device scenario, the system automatically selects a master device, and other devices synchronize according to the time of the master device;

[0048] The multi-device expansion and coordination uses a global synchronization time formula, which is as follows:

[0049]

[0050] where t global is the global synchronization time, t sync_i is the synchronization time of the i-th device, and m is the number of devices.

[0051] In the present invention, in step S7, the steps of security and fault tolerance mechanism are as follows:

[0052] Step S701, adopt timestamp signature and message authentication to prevent time synchronization from being attacked or interfered;

[0053] Step S702, in the case of partial device failure or communication interruption, the system automatically switches to standby devices to ensure the synchronization of other devices;

[0054] Step S703, the system has self-repair ability. After the abnormal situation is restored, it automatically re-performs clock synchronization;

[0055] The security and fault tolerance mechanism uses a message verification formula, which is specifically as follows:

[0056] Verify(msg, sig) = True

[0057] Among them, Verify(msg, sig) is a function to verify the message and signature. Returning True indicates that the verification passes. msg is the message content, and sig is the message signature.

[0058] Compared with the prior art, the beneficial effects of the present invention are:

[0059] 1. The present invention measures the signal delay in real time through multiple round-trip communications, and dynamically adjusts the measurement frequency according to the delay change to ensure high-precision synchronization in a dynamic environment. At the same time, when calculating the clock deviation, the dynamic delay is taken into consideration, and the local clock is adjusted through a delay compensation algorithm to reduce the synchronization error.

[0060] 2. The present invention monitors the changes in the communication environment in real time, and dynamically adjusts the synchronization strategy according to the delay change amount to ensure the stable operation of the system in a complex environment. In addition, through timestamp signature and message authentication, it prevents time synchronization from being attacked or interfered, and has a fault tolerance mechanism, so that other devices can still maintain synchronization in the case of partial device failure or communication interruption. Brief Description of the Drawings

[0061] Figure 1 It is a schematic flow chart of a method for precise measurement and synchronization of signal delay for the present invention in a complex communication environment. Detailed Embodiments

[0062] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0063] Please refer to Figure 1 , the present invention provides a technical solution:

[0064] A method for precise measurement and synchronization of signal delay in a complex communication environment, including the following steps:

[0065] Step S1, distributed clock initialization. All devices initialize through the local clock and record the initial timestamp, and generate a unique device ID;

[0066] In this step, the timestamps recorded during device initialization include the initial value of the local clock and the device ID, which are used for subsequent clock deviation calculation and synchronization.

[0067] Step S2, Clock deviation calculation. The devices exchange timestamp information through wireless communication to calculate the clock deviation between each other.

[0068] In this step, the steps of clock deviation calculation are as follows:

[0069] Step S201, Device A sends a message containing the local timestamp to Device B.

[0070] Step S202, Device B records the received timestamp and calculates the clock deviation from Device A.

[0071] Step S203, Device B returns the calculation result to Device A, and Device A adjusts its local clock according to the returned result.

[0072] The clock deviation calculation uses the clock deviation formula, which is specifically as follows:

[0073] Δt AB =t B_recv -t A_send

[0074] where, Δt AB is the clock deviation between Device A and Device B, t B_recv is the timestamp when Device B receives the message sent by Device A, and t A_send is the timestamp when Device A sends the message.

[0075] When calculating the clock deviation, the transmission delay Delay avg will affect the result. To separate the clock deviation and the transmission delay, the average delay can be calculated through multiple round-trip communications, and the following formula is used to correct the clock deviation:

[0076]

[0077] Step S3, Adaptive delay measurement. The devices measure the transmission delay through multiple round-trip communications and dynamically adjust the measurement frequency according to the delay change.

[0078] In this step, the steps of adaptive delay measurement are as follows:

[0079] Step S301, The devices perform multiple round-trip communications and record the send and receive timestamps for each communication.

[0080] Step S302, Calculate the average transmission delay and dynamically adjust the measurement frequency according to the delay change.

[0081] Step S303, in the case of a large delay variation, increase the measurement frequency to improve the measurement accuracy;

[0082] The adaptive delay measurement uses the average delay formula, which is as follows:

[0083]

[0084] Among them, Delay avg is the average transmission delay, t B_recv_i is the timestamp when device B receives the message in the i-th communication, t A_send_i is the timestamp when device A sends the message in the i-th communication, and n is the number of communications.

[0085] To adapt to the dynamic environment, the measurement frequency f measure needs to be dynamically adjusted according to the delay variation ΔDelay. The specific rules are as follows:

[0086]

[0087] Step S4, delay compensation and synchronization. According to the measured transmission delay and clock deviation, the device dynamically adjusts the local clock for delay compensation;

[0088] In this step, the steps of delay compensation and synchronization are as follows:

[0089] Step S401, according to the measured transmission delay and clock deviation, the device calculates the synchronization time;

[0090] Step S402, the device adjusts the local clock and synchronizes with the master device or other devices;

[0091] Step S403, before each acquisition task starts, perform a delay compensation to ensure the synchronization of data acquisition;

[0092] The delay compensation and synchronization use the synchronization time formula, which is as follows:

[0093] t sync = t local + Δt AB + Delay avg

[0094] Among them, t sync is the synchronized time, t local is the local clock time, Δt AB is the clock deviation between device A and device B, and Delay avg is the average transmission delay.

[0095] In the synchronization time calculation, clock adjustment may introduce jitter. In order to reduce the impact of jitter, a low-pass filter can be used to smooth the clock adjustment to obtain the filtered jitter value Jitter filtered , and correct the synchronization time:

[0096] t sync =t local +Δt AB +Delay avg +Jitter filtered

[0097] Step S5, dynamic environment monitoring and adjustment, the system continuously monitors changes in the communication environment and dynamically adjusts delay measurement and synchronization strategies according to environmental changes;

[0098] In this step, the steps of dynamic environment monitoring and adjustment are as follows:

[0099] Step S501, the system monitors changes in the communication environment in real time, including changes in signal strength, interference level, and device location;

[0100] Step S502, dynamically adjusting the delay measurement and synchronization strategy according to environmental changes, and in the case of large signal interference, increasing the delay measurement frequency or using a more robust synchronization algorithm;

[0101] The dynamic environment monitoring and adjustment uses an adaptive frequency adjustment formula, which is as follows:

[0102]

[0103] Among them, f measure is the adjusted measurement frequency, f base is the basic measurement frequency, ΔDelay is the delay change, Delay threshold is the delay variation threshold.

[0104] In a dynamic environment, signal strength (RSSI) and interference level will also affect the measurement frequency. Therefore, the calculation formula for the measurement frequency can be further modified as follows:

[0105]

[0106] Step S6, multi-device expansion and coordination, using a distributed coordination algorithm to keep all devices synchronized;

[0107] In this step, the steps of multi-device expansion and coordination are as follows:

[0108] Step S601, using a distributed coordination algorithm to keep all devices synchronized;

[0109] Step S602, each device calculates the global synchronization time according to the communication results with other devices, and adjusts the local clock;

[0110] Step S602: In a multi-device scenario, the system automatically selects a master device, and other devices synchronize according to the time of the master device;

[0111] The multi-device expansion and coordination uses a global synchronization time formula, which is as follows:

[0112]

[0113] Among them, t global is the global synchronization time, t sync_i is the synchronization time of the ith device, and m is the number of devices.

[0114] In a multi-device environment, the clock deviation of the master device is Δt master This will affect the global synchronization time. Therefore, the calculation formula for the global synchronization time can be modified to:

[0115]

[0116] Step S7, security and fault-tolerance mechanism, uses timestamp signature and message authentication to prevent time synchronization from being attacked or interfered with, and has a fault-tolerance mechanism to keep other devices synchronized when some devices fail or communication is interrupted.

[0117] In this step, the steps of security and fault tolerance mechanism are as follows:

[0118] Step S701, using timestamp signature and message authentication to prevent time synchronization from being attacked or interfered;

[0119] Step S702, when some devices fail or communication is interrupted, the system automatically switches to a backup device to ensure synchronization of other devices;

[0120] Step S703, the system has self-repair capability and automatically resynchronizes the clock after the abnormal situation is recovered;

[0121] The security and fault tolerance mechanism uses a message verification formula, which is as follows:

[0122] Verify(msg,sig)=True

[0123] Verify(msg,sig) is a function for verifying messages and signatures. Returning True indicates that the verification is successful. msg is the message content, and sig is the message signature.

[0124] To ensure the security of the timestamp, HMAC or digital signature can be used to authenticate the timestamp. The verification formula can be specified as:

[0125] Verify(msg,sig)=HMAC(msg,key)==sig

[0126] In a specific embodiment, in an industrial Internet of Things environment, there are three devices (device A, device B, and device C) that need to be synchronized through wireless communication. Device A is the master device, and devices B and C are slave devices. There are certain signal interference and delay changes in the communication environment.

[0127] Step S1, device A, device B and device C respectively initialize local clocks and record initial timestamps and unique device IDs.

[0128] Initial timestamp of device A: t A_init =1000.

[0129] Device B’s initial timestamp: t B_init =1005.

[0130] Initial timestamp of device C: t C_init =1010.

[0131] Step S2: Device A sends a message to device B. Device B records the receiving timestamp and calculates the clock deviation.

[0132] The timestamp of the message sent by device A: t A_send =1000.

[0133] The timestamp of the message received by device B: t B_recv =1006.

[0134] Clock deviation calculation: Δt AB =t B_recv -t A_send =1006-1000=6.

[0135] In step S3, device A and device B perform three round trip communications, record the sending and receiving timestamps of each communication, and calculate the average transmission delay.

[0136] 1st communication:

[0137] Device A sends timestamp: t A_send_1 =1000.

[0138] Device B receives the timestamp: t B_recv_1 =1006.

[0139] 2nd communication:.

[0140] Device A sends timestamp: t A_send_2 =1002.

[0141] Device B receives the timestamp: t B_recv_2 =1008.

[0142] 3rd communication:.

[0143] Device A sends timestamp: t A_send_3 =1004.

[0144] Device B receives the timestamp: t B_recv_3 =1010.

[0145] Average transmission delay calculation:

[0146]

[0147] Step S4: Device B adjusts the local clock according to the measured transmission delay and clock deviation to synchronize with device A.

[0148] Synchronous time calculation: t sync =t local +Δt AB +Delay avg =1006+6+6=1018.

[0149] Device B adjusts its local clock to t sync =1018, synchronized with device A.

[0150] Step S5: The system detects that the signal interference in the communication environment increases, and dynamically adjusts the delay measurement frequency.

[0151] Basic measurement frequency: f base =1HZ.

[0152] Delay change: ΔDelay=2.

[0153] Delay change threshold: Delay threshold =1.

[0154] Adjusted measurement frequency:

[0155]

[0156] Step S6: Device A, device B and device C maintain synchronization through a distributed coordination algorithm.

[0157] Synchronization time of device A: t sync_A =1000.

[0158] Device B synchronization time: t sync_B =1018.

[0159] Synchronization time of device C: t sync_C =1020.

[0160] Global synchronization time calculation:

[0161]

[0162] Step S7, device B receives the timestamp message from device A and verifies the message signature.

[0163] Message sent by device A: msg = "Time: 1000".

[0164] Signature generated by device A: sig = HMAC (msg, key).

[0165] Device B verifies the signature:

[0166] Verify(msg,sig)=HMAC(msg,key)==sig.

[0167] If the verification passes, device B accepts the timestamp message; otherwise, it discards the message.

[0168] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0169] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A signal delay accurate measurement and synchronization method for complex communication environments, characterized in that: The following steps are involved: Step S1, distributed clock initialization, all devices are initialized through local clocks and record initial timestamps to generate unique device IDs; Step S2, clock deviation calculation, the devices exchange timestamp information through wireless communication and calculate the clock deviation between each other; Step S3, adaptive delay measurement, measuring the transmission delay between devices through multiple round-trip communications, and dynamically adjusting the measurement frequency according to the delay change; Step S4, delay compensation and synchronization, according to the measured transmission delay and clock deviation, the device dynamically adjusts the local clock to perform delay compensation; Step S5, dynamic environment monitoring and adjustment, the system continuously monitors changes in the communication environment and dynamically adjusts delay measurement and synchronization strategies according to environmental changes; Step S6, multi-device expansion and coordination, using a distributed coordination algorithm to keep all devices synchronized; Step S7, security and fault-tolerance mechanism, uses timestamp signature and message authentication to prevent time synchronization from being attacked or interfered with, and has a fault-tolerance mechanism to keep other devices synchronized when some devices fail or communication is interrupted.

2. The method for accurately measuring and synchronizing signal delay in a complex communication environment according to claim 1, characterized in that: In step S1, the timestamp recorded when the device is initialized includes the initial value of the local clock and the device ID, which is used for subsequent clock deviation calculation and synchronization.

3. The method for accurately measuring and synchronizing signal delay in a complex communication environment according to claim 1, characterized in that: In step S2, the steps of calculating the clock deviation are as follows: Step S201, device A sends a message containing a local timestamp to device B; Step S202, device B records the receiving timestamp and calculates the clock deviation with device A; Step S203: Device B returns the calculation result to device A, and device A adjusts the local clock according to the returned result. The clock deviation calculation uses the clock deviation formula, which is as follows: Δt AB =t B_recv -t A_send Among them, Δt AB is the clock deviation between device A and device B, t B_recv is the timestamp when device B receives the message sent by device A, t A_send It is the timestamp when device A sends the message.

4. The method for accurately measuring and synchronizing signal delay in a complex communication environment according to claim 1, characterized in that: In step S3, the steps of adaptive delay measurement are as follows: Step S301, multiple round-trip communications are performed between devices, and the sending and receiving timestamps of each communication are recorded; Step S302, calculating the average transmission delay and dynamically adjusting the measurement frequency according to the delay variation; Step S303, when the delay variation is large, increasing the measurement frequency to improve the measurement accuracy; The adaptive delay measurement uses the average delay formula, which is as follows: Among them, Delay avg is the average transmission delay, t B_recv_i is the timestamp of device B receiving the message in the i-th communication, t A_send_i is the timestamp of the message sent by device A in the i-th communication, and n is the number of communications.

5. The method for accurate measurement and synchronization of signal delay in a complex communication environment according to claim 1, characterized in that: In step S4, the delay compensation and synchronization steps are as follows: Step S401, the device calculates the synchronization time according to the measured transmission delay and clock deviation; Step S402, the device adjusts the local clock and synchronizes the time with the master device or other devices; Step S403, before each acquisition task starts, a delay compensation is performed to ensure synchronization of data acquisition; The delay compensation and synchronization use the synchronization time formula, which is as follows: t sync =t local +Δt AB +Delay avg Among them, t sync is the time after synchronization, t local is the local clock time, Δt AB is the clock deviation between device A and device B. avg is the average transmission delay.

6. The method for accurate measurement and synchronization of signal delay in a complex communication environment according to claim 1, characterized in that: In step S5, the steps of dynamic environment monitoring and adjustment are as follows: Step S501, the system monitors changes in the communication environment in real time, including changes in signal strength, interference level, and device location; Step S502, dynamically adjusting the delay measurement and synchronization strategy according to environmental changes, and in the case of large signal interference, increasing the delay measurement frequency or using a more robust synchronization algorithm; The dynamic environment monitoring and adjustment uses an adaptive frequency adjustment formula, which is as follows: Among them, f measure is the adjusted measurement frequency, f base is the basic measurement frequency, ΔDelay is the delay change, Delay threshold is the delay variation threshold.

7. The method for accurate measurement and synchronization of signal delay in a complex communication environment according to claim 1, characterized in that: In step S6, the steps of multi-device expansion and coordination are as follows: Step S601, using a distributed coordination algorithm to keep all devices synchronized; Step S602, each device calculates the global synchronization time according to the communication results with other devices, and adjusts the local clock; Step S602: In a multi-device scenario, the system automatically selects a master device, and other devices synchronize according to the time of the master device; The multi-device expansion and coordination uses a global synchronization time formula, which is as follows: Among them, t global is the global synchronization time, t sync＿i is the synchronization time of the ith device, and m is the number of devices.

8. The method for accurate measurement and synchronization of signal delay in a complex communication environment according to claim 1, characterized in that: In step S7, the steps of the security and fault tolerance mechanism are as follows: Step S701, using timestamp signature and message authentication to prevent time synchronization from being attacked or interfered; Step S702, when some devices fail or communication is interrupted, the system automatically switches to a backup device to ensure synchronization of other devices; Step S703, the system has self-repair capability and automatically resynchronizes the clock after the abnormal situation is recovered; The security and fault tolerance mechanism uses a message verification formula, which is as follows: Verify(msg,sig)=True Verify(msg,sig) is a function for verifying messages and signatures. Returning True indicates that the verification is successful. msg is the message content, and sig is the message signature.

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