A method, system and medium for frequency diversity enhanced repeat transmission for flat fading channels

Abstract

This invention relates to a method, system, and medium for frequency diversity enhancement of repetitive transmission in flat fading channels. The method includes the following steps: obtaining the total number of resource units N of the communication system and the retransmission count K of the terminal devices; selecting a corresponding frequency hopping pattern generation strategy based on the value of the retransmission count K, and generating a frequency hopping pattern that matches the total number of resource units N and the retransmission count K while considering the impact of flat fading; uniquely assigning the generated frequency hopping pattern to multiple URLLC devices; and repeatedly transmitting the same data packets on K resource units within a single time slot according to the assigned frequency hopping pattern. This invention meets the communication requirements of ultra-high reliability and low latency for URLLC devices, supports a larger number of devices in a given resource scenario, and mitigates the impact of flat fading on frequency gain.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a method, system, and medium for frequency diversity enhancement repetitive transmission for flat fading channels. Background Technology

[0002] URLLC is an important service category supported by fifth-generation (5G) mobile communication networks. Based on its high reliability and low latency performance, URLLC can be used for monitoring and early warning of emergencies. According to the specifications of the 3rd Generation Partnership Project (3GPP), an URLLC device needs to complete short packet transmission within a communication transmission latency of less than 1 millisecond, and the packet loss probability of the short packets should not exceed 10%. -6 .

[0003] To reduce transmission latency, URLLC devices typically transmit short data packets of a few tens of bytes and use unauthorized access methods to control latency. To reduce the probability of collisions, URLLC devices employ retransmission technology, that is, for the same message, multiple resource units are selected consecutively to transmit K copies.

[0004] The technologies currently used include: 1) K random retransmission, where the device randomly selects K resource units for repeated transmission. This transmission method is difficult to support multiple devices when resources are limited and the transmission probability of the device is high; 2) K deterministic pattern retransmission based on Steinersystem, which can generate frequency hopping patterns when the number of resource units and the number of retransmissions are divisible.

[0005] In existing technical solutions, K random retransmissions are difficult to support multiple devices under resource constraints and high device transmission probability. K deterministic pattern retransmissions based on the Steiner system are subject to stringent construction conditions, namely, frequency hopping patterns can only be generated when the number of resource units and the number of retransmissions are divisible. This cannot support the generation of frequency hopping patterns with any given number of resource units and number of retransmissions in real-world scenarios.

[0006] In automated industrial scenarios, resource units often experience flat fading. However, neither of the two frequency hopping patterns mentioned above considers the impact of flat fading on frequency gain. This results in the generated frequency hopping patterns failing to fully utilize the frequency hopping gain to reduce the probability of message decoding errors.

[0007] Therefore, existing technical solutions are not suitable for deploying URLLC devices in automated industrial environments. Summary of the Invention

[0008] This invention provides a method, system, and medium for frequency diversity enhancement of repetitive transmission in flat fading channels, aiming to meet the communication requirements of ultra-high reliability and low latency for URLLC devices, support a larger number of devices in resource-constrained scenarios, and mitigate the impact of flat fading on frequency gain.

[0009] To achieve the above objectives, the present invention provides a method for frequency diversity enhancement of repetitive transmissions in flat fading channels, the method comprising the following steps: Step S10: Obtain the total number of resource units N of the communication system and the number of retransmissions K of the terminal device; Step S20: Based on the value of the number of retransmissions K, select the corresponding frequency hopping pattern generation strategy, and generate a frequency hopping pattern that matches the total number of resource units N and the number of retransmissions K, taking into account the influence of flat fading. Step S30: The generated frequency hopping pattern is uniquely assigned to multiple URLLC devices; In step S40, the URLLC device repeatedly transmits the same data packet on K resource units within a single time slot according to the assigned frequency hopping pattern.

[0010] A further technical solution of the present invention is that step S20 includes: Step S201: When K=2, select the frequency hopping pattern generation strategy based on the cyclic graph model. Considering the influence of flat fading, generate a frequency hopping pattern that matches the total number of resource units N and the number of retransmissions K. Step S202: When K>2, a frequency hopping pattern matching the total number of resource units N and the number of retransmissions K is generated by using a strategy of symmetric balanced incomplete block design, taking into account the influence of flat fading.

[0011] A further technical solution of the present invention is that, in step S201, assuming that each resource unit appears Z times in all generated frequency hopping patterns, and the number of resource units is N, step S201 specifically includes the following steps: Step S2011: Initialize the connection set of the cyclic graph to Q={1,2,…,N / 2}, which contains all natural numbers from 1 to N / 2, and the number of connections C=Z / 2; In step S2012, when considering the effect of flat fading, select the C elements with the largest values ​​from set Q to form set J. Then the total number of elements in set J is C. Step S2013: Initialize loop index i=1 and start the loop; In step S2014, if the circular index does not exceed N, then proceed to steps S2015 to S2018; otherwise, end all processes. Step S2015: Initialize the loop index j=1 for generating the frequency hopping pattern and start the loop; In step S2016, if the circular index does not exceed C, then execute steps S2017 and S2018; otherwise, execute step S2019 and jump back to step S2014 for judgment. Step S2017: Extract the element corresponding to index j from set J, denoted as... ; Step S2018: Calculate the specific frequency hopping pattern using formula (1): (1) The mod operator represents calculating... The remainder after dividing N; Step S2019, increment the index by 1.

[0012] A further technical solution of the present invention is that, in step S202, assuming the number of resource units is N, and H={1,2,…,N-1} contains natural numbers from 1 to N-1, step S202 specifically includes: Step S2021: Place all combinations of selecting K-1 natural numbers from the N / 2 natural numbers from 1 to N / 2 into set ω. Let |ω| represent the total number of combinations in set ω. The i-th combination in set ω is recorded as: (2) This combination contains K-1 natural numbers selected from the N / 2 natural numbers from 1 to N / 2 as a combination; Step S2022: Initialize the loop index i = 1; Step S2023: Start executing the loop. If index i is less than |ω|, then execute steps S2024 to S20212; otherwise, execute steps S20213 and S20214. Step S2024: Extract the combination corresponding to index i from set ω, denoted as: (3) According to formula (4), this combination is used to form the basic block B, and the combination is accumulated starting from the natural number 0: (4) According to formula (5), subtract any two elements in the basic block B and find the remainder to obtain the difference. Combine the different differences into a set. : (5) Step S2025: If If the element contained in the formula is equal to K(K-1), then proceed to steps S2026 to S20212; otherwise, return to step S2023. Step S2026: Initialize set H, H={1,2,…,N-1} containing natural numbers from 1 to N-1. Then, according to formula (6), perform a removal operation on set H, that is, remove the set... All elements contained in set H are removed: (6) Step S2027: Include all elements of combination B in the set shown in formula (7). (7) Step S2028: Select the combination corresponding to index j from set ω: (8) Step S2029: The operation performed is the same as in step S2024; Step S20210: Determine If all elements are contained in set H, then execute steps S20211 and S20212; otherwise execute steps S20213 and S2026. Step S20211: Determine whether index j is less than |ω|. If yes, proceed to step S20212; otherwise, proceed to step S2023. Step S20212: According to formula (9), perform a removal operation on set H, that is, remove set H. All elements contained in set H are removed: (9) Include all elements of combination B in a set as shown in formula (10). (10) Step S2013, execute index j = j + 1; Step S20214: Find the value with the largest value according to formula (11). and assign it to α (11) Step S20215: Subtract any two elements of each combination contained in α and sum the differences to obtain the average value, which is then placed into set φ.

[0013] To achieve the above objectives, the present invention also proposes a system for frequency diversity enhancement repetitive transmission for flat fading channels. The system includes a memory, a processor, and a program for frequency diversity enhancement repetitive transmission for flat fading channels stored on the processor. The program for frequency diversity enhancement repetitive transmission for flat fading channels is executed by the processor to perform the steps of the method described above.

[0014] To achieve the above objectives, the present invention also proposes a computer-readable storage medium storing a program for frequency diversity enhancement repetitive transmission for flat fading channels, wherein the program for frequency diversity enhancement repetitive transmission for flat fading channels is executed by a processor to perform the steps of the method described above.

[0015] The beneficial effects of the frequency diversity enhancement repetitive transmission method for flat fading channels of the present invention are: This invention, through the above technical solution, obtains the total number of resource units N of the communication system and the retransmission count K of the terminal device; based on the value of the retransmission count K, selects a corresponding frequency hopping pattern generation strategy, and generates a frequency hopping pattern that matches the total number of resource units N and the retransmission count K while considering the influence of flat fading; uniquely assigns the generated frequency hopping pattern to multiple URLLC devices; the URLLC devices repeatedly transmit the same data packets on K resource units in a single time slot according to the assigned frequency hopping pattern, which can meet the ultra-high reliability and low latency communication indicators of URLLC devices, support a larger number of devices in a given resource scenario, and mitigate the impact of flat fading on frequency gain. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating a preferred embodiment of the method for enhancing repetitive transmissions through frequency diversity in flat fading channels according to the present invention. Figure 2 This is a schematic diagram of the system model involved in a preferred embodiment of the method for frequency diversity enhancement of repetitive transmission for flat fading channels according to the present invention; Figure 3 This is a flowchart of the frequency hopping pattern design for K=2; Figure 4 This is a flowchart for designing frequency hopping patterns with K>2; Figure 5 This is a hardware architecture diagram of the system for frequency diversity enhancement of repetitive transmission for flat fading channels according to the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0018] Currently, URLLC (Ultra-Reliable Low-Latency Communication) devices, whether slow-moving or static, are widely deployed in industrial automation scenarios. Due to limited channel resources, existing random access schemes can only support a limited number of devices; existing frequency band selection schemes cannot support arbitrary given retransmission counts and resource blocks. Furthermore, in automated factories, the spatial constraints of the communication environment result in very small statistical latency spread, leading to flat fading. This fading causes significant correlation between adjacent resource units, severely weakening the frequency gain between them. Therefore, to meet the ultra-high reliability and low latency communication requirements of URLLC devices, support a larger number of devices within a given resource context, and mitigate the impact of flat fading on frequency gain, this invention proposes a practical improvement design for frequency diversity enhancement repetitive transmission in flat-fading channels. Specifically, it involves a method for frequency diversity enhancement repetitive transmission in flat-fading channels, primarily applied to optimize the number of supported ultra-reliable low-latency communication (URLLC) devices and reduce the impact of flat fading on frequency gain in scenarios with limited channel resources. Specifically, this invention employs a K-times retransmission method, which selects K resource units within a single time slot to transmit the same message to avoid message collisions between different devices. For K-times retransmission, this invention designs a practical and improved frequency hopping pattern design. This design can generate frequency hopping patterns under any given number of retransmissions and resource units. These patterns are assigned one-to-one to devices, ensuring that the collision probability between devices meets the URLLC reliability requirements. When K=2, this invention generates frequency hopping patterns by constructing a cyclic graph, considering the influence of flat fading. When K>2, this invention generates frequency hopping patterns by using a symmetric balanced incomplete block design method, considering the influence of flat fading.

[0019] Specifically, such as Figure 1 As shown, a preferred embodiment of the frequency diversity enhancement repetitive transmission method for flat fading channels of the present invention includes the following steps: Step S10: Obtain the total number of resource units N of the communication system and the number of retransmissions K of the terminal device.

[0020] This embodiment considers the deployment of a large number of URLLC devices within a single cellular base station. The system model is as follows: Figure 2As shown, this includes multiple URLLC devices and one cellular base station. All devices share all resource units. Devices 1 through 3 transmit short packets at specific times. Each device selects a different resource unit to transmit short packets within the same time slot according to the frequency hopping pattern generated by the design scheme. However, three devices simultaneously selected resource unit 2, resulting in a packet collision; while other different resource units selected by these devices did not cause packet collisions. The packet collision directly caused the short packet reception failure.

[0021] Step S20: Based on the value of the number of retransmissions K, select the corresponding frequency hopping pattern generation strategy, and generate a frequency hopping pattern that matches the total number of resource units N and the number of retransmissions K, taking into account the influence of flat fading.

[0022] Step S30: The generated frequency hopping pattern is uniquely assigned to multiple URLLC devices.

[0023] In step S40, the URLLC device repeatedly transmits the same data packet on K resource units within a single time slot according to the assigned frequency hopping pattern.

[0024] In this embodiment, step S20 specifically includes: Step S201: When K=2, select the frequency hopping pattern generation strategy based on the cyclic graph model. Considering the influence of flat fading, generate a frequency hopping pattern that matches the total number of resource units N and the number of retransmissions K.

[0025] Step S202: When K>2, a frequency hopping pattern matching the total number of resource units N and the number of retransmissions K is generated by using a strategy of symmetric balanced incomplete block design, taking into account the influence of flat fading.

[0026] In step S201, it is assumed that each resource element appears Z times in all generated frequency hopping patterns, and the number of resource elements is N. Figure 3 As shown, step S201 specifically includes the following steps: Step S2011: Initialize the connection set of the cyclic graph to Q={1,2,…,N / 2}, which contains all natural numbers from 1 to N / 2, and the number of connections C=Z / 2; In step S2012, when considering the effect of flat fading, select the C elements with the largest values ​​from set Q to form set J. Then the total number of elements in set J is C. Step S2013: Initialize loop index i=1 and start the loop; In step S2014, if the circular index does not exceed N, then proceed to steps S2015 to S2018; otherwise, end all processes. Step S2015: Initialize the loop index j=1 for generating the frequency hopping pattern and start the loop; In step S2016, if the circular index does not exceed C, then execute steps S2017 and S2018; otherwise, execute step S2019 and jump back to step S2014 for judgment. Step S2017: Extract the element corresponding to index j from set J, denoted as... ; Step S2018: Calculate the specific frequency hopping pattern using formula (1): (1) The mod operator represents calculating... The remainder after dividing N; In step S2019, increment index i by 1.

[0027] In step S202, it is assumed that the number of resource units is N, and H={1,2,…,N-1} contains natural numbers from 1 to N-1, such as... Figure 4 As shown, step S202 specifically includes: Step S2021: Place all combinations of selecting K-1 natural numbers from the N / 2 natural numbers from 1 to N / 2 into set ω. Let |ω| represent the total number of combinations in set ω. The i-th combination in set ω is recorded as: (2) This combination contains K-1 natural numbers selected from the N / 2 natural numbers from 1 to N / 2 as a combination; Step S2022: Initialize the loop index i = 1; Step S2023: Start executing the loop. If index i is less than |ω|, then execute steps S2024 to S20212; otherwise, execute steps S20213 and S20214. Step S2024: Extract the combination corresponding to index i from set ω, denoted as: (3) According to formula (4), this combination is used to form the basic block B, and the combination is accumulated starting from the natural number 0: (4) According to formula (5), subtract any two elements in the basic block B and find the remainder to obtain the difference. Combine the different differences into a set. : (5) Step S2025: If If the element contained in the formula is equal to K(K-1), then proceed to steps S2026 to S20212; otherwise, return to step S2023. Step S2026: Initialize set H, H={1,2,…,N-1} containing natural numbers from 1 to N-1. Then, according to formula (6), perform a removal operation on set H, that is, remove the set... All elements contained in set H are removed: (6) Step S2027: Include all elements of combination B in the set shown in formula (7). (7) Step S2028: Select the combination corresponding to index j from set ω: (8) Step S2029: The operation performed is the same as in step S2024; Step S20210: Determine If all elements are contained in set H, then execute steps S20211 and S20212; otherwise execute steps S20213 and S2026. Step S20211: Determine whether index j is less than |ω|. If yes, proceed to step S20212; otherwise, proceed to step S2023. Step S20212: According to formula (9), perform a removal operation on set H, that is, remove set H. All elements contained in set H are removed: (9) Include all elements of combination B in a set as shown in formula (10). (10) Step S2013, execute index j = j + 1; Step S20214: Find the value with the largest value according to formula (11). and assign it to α (11) Step S20215: Subtract any two elements of each combination contained in α and sum the differences to obtain the average value, which is then placed into set φ.

[0028] The beneficial effects of the frequency diversity enhancement repetitive transmission method for flat fading channels of the present invention are: This invention, through the above technical solution, obtains the total number of resource units N of the communication system and the retransmission count K of the terminal device; based on the value of the retransmission count K, selects a corresponding frequency hopping pattern generation strategy, and generates a frequency hopping pattern that matches the total number of resource units N and the retransmission count K while considering the influence of flat fading; uniquely assigns the generated frequency hopping pattern to multiple URLLC devices; the URLLC devices repeatedly transmit the same data packets on K resource units in a single time slot according to the assigned frequency hopping pattern, which can meet the ultra-high reliability and low latency communication indicators of URLLC devices, support a larger number of devices in a given resource scenario, and mitigate the impact of flat fading on frequency gain.

[0029] To achieve the above objectives, this invention also proposes a system for frequency diversity enhancement of repetitive transmissions in flat fading channels, such as... Figure 5 As shown, the system includes a processor 1001, a CPU, a network interface 1004, a user interface 1003, a memory 1005, a communication bus 1002, and a program for frequency diversity enhancement repetitive transmission for flat fading channels stored on the processor. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen or an input unit such as a keyboard. Optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 1005 may be high-speed RAM or non-volatile memory, such as a disk drive. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0030] Those skilled in the art will understand that Figure 5 The system structure shown does not constitute a limitation on the system and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0031] like Figure 5 As shown, the memory 1005, which serves as a computer storage medium, may include an operating device, a network communication module, a user interface module, and a generation program for frequency diversity enhancement repetitive transmission for flat fading channels.

[0032] exist Figure 5In the system shown, network interface 1004 is mainly used to connect to the network server and communicate with the network server; user interface 1003 is mainly used to interact with user terminals and receive user input instructions; and processor 1001 can be used to call the frequency diversity enhancement repetitive transmission program for flat fading channels stored in memory 1005.

[0033] To achieve the above objectives, the present invention also proposes a computer-readable storage medium storing a program for frequency diversity enhancement repetitive transmission for flat fading channels. When the program for frequency diversity enhancement repetitive transmission for flat fading channels is run by a processor, the steps of the method described above are executed, and will not be repeated here.

[0034] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for frequency diversity enhancement of repetitive transmission in flat fading channels, characterized in that, The method includes the following steps: Step S10: Obtain the total number of resource units N of the communication system and the number of retransmissions K of the terminal device; Step S20: Based on the value of the number of retransmissions K, select the corresponding frequency hopping pattern generation strategy, and generate a frequency hopping pattern that matches the total number of resource units N and the number of retransmissions K, taking into account the influence of flat fading. Step S30: The generated frequency hopping pattern is uniquely assigned to multiple URLLC devices; In step S40, the URLLC device repeatedly transmits the same data packet on K resource units within a single time slot according to the assigned frequency hopping pattern.

2. The method for frequency diversity enhancement repetitive transmission for flat fading channels according to claim 1, characterized in that, Step S20 includes: Step S201: When K=2, select the frequency hopping pattern generation strategy based on the cyclic graph model. Considering the influence of flat fading, generate a frequency hopping pattern that matches the total number of resource units N and the number of retransmissions K. Step S202: When K>2, a frequency hopping pattern matching the total number of resource units N and the number of retransmissions K is generated by using a strategy of symmetric balanced incomplete block design, taking into account the influence of flat fading.

3. The method for frequency diversity enhancement repetitive transmission for flat fading channels according to claim 2, characterized in that, In step S201, it is assumed that each resource element appears Z times in all generated frequency hopping patterns, and the number of resource elements is N. Step S201 specifically includes the following steps: Step S2011: Initialize the connection set of the cyclic graph to Q={1,2,…,N / 2}, which contains all natural numbers from 1 to N / 2, and the number of connections C=Z / 2; In step S2012, when considering the effect of flat fading, select the C elements with the largest values ​​from set Q to form set J. Then the total number of elements in set J is C. Step S2013: Initialize loop index i=1 and start the loop; In step S2014, if the circular index does not exceed N, then proceed to steps S2015 to S2018; otherwise, end all processes. Step S2015: Initialize the loop index j=1 for generating the frequency hopping pattern and start the loop; In step S2016, if the circular index does not exceed C, then execute steps S2017 and S2018; otherwise, execute step S2019 and jump back to step S2014 for judgment. Step S2017: Extract the element corresponding to index j from set J, denoted as... ; Step S2018: Calculate the specific frequency hopping pattern using formula (1): （1） The mod operator represents calculating... The remainder after being divided by N; Step S2019, increment the index by 1.

4. The method for frequency diversity enhancement repetitive transmission for flat fading channels according to claim 2, characterized in that, In step S202, assuming the number of resource units is N, and H = {1, 2, ..., N-1} contains natural numbers from 1 to N-1, step S202 specifically includes: Step S2021: Place all combinations of selecting K-1 natural numbers from the N / 2 natural numbers from 1 to N / 2 into set ω. Let |ω| represent the total number of combinations contained in set ω. The i-th combination in set ω is recorded as: （2） This combination contains K-1 natural numbers selected from the N / 2 natural numbers from 1 to N / 2 as a combination; Step S2022: Initialize the loop index i = 1; Step S2023: Start executing the loop. If index i is less than |ω|, then execute steps S2024 to S20212; otherwise, execute steps S20213 and S20214. Step S2024: Extract the combination corresponding to index i from set ω, denoted as: （3） According to formula (4), this combination is used to form the basic block B, and the combination is accumulated starting from the natural number 0: （4） According to formula (5), subtract any two elements in the basic block B and find the remainder to obtain the difference. Combine the different differences into a set. : （5） Step S2025: If If the element contained in the formula is equal to K(K-1), then proceed to steps S2026 to S20212; otherwise, return to step S2023. Step S2026: Initialize set H, H={1,2,…,N-1} containing natural numbers from 1 to N-1. Then, according to formula (6), perform a removal operation on set H, that is, remove the set... All elements contained in the set H are removed: （6） Step S2027: Include all elements of combination B in the set shown in formula (7). （7） Step S2028: Select the combination corresponding to index j from set ω: （8） Step S2029: The operation performed is the same as in step S2024; Step S20210: Determine If all elements are contained in set H, then execute steps S20211 and S20212; otherwise execute steps S20213 and S2026. Step S20211: Determine whether index j is less than |ω|. If yes, proceed to step S20212; otherwise, proceed to step S2023. Step S20212: According to formula (9), perform a removal operation on set H, that is, remove set H. All elements contained in the set H are removed: （9） Include all elements of combination B in a set as shown in formula (10). （10） Step S2013, execute index j = j + 1; Step S20214: Find the largest value according to formula (11). and assign it to α （11） Step S20215: Subtract any two elements of each combination contained in α and sum the differences to obtain the average value, which is then placed into set φ.

5. A system for frequency diversity enhancement repetitive transmission in flat fading channels, characterized in that, The system includes a memory, a processor, and a program for frequency diversity enhancement repetitive transmission for flat fading channels stored on the processor, the program being executed by the processor to perform the steps of the method as described in any one of claims 1 to 4.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program for frequency diversity enhancement repetitive transmission for flat fading channels, which, when executed by a processor, performs the steps of the method as described in any one of claims 1 to 4.

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