A resource allocation method based on link influence in dual-protocol quantum optical networks

Abstract

This patent discloses a resource allocation method based on link influence in a dual-protocol quantum optical network. This method is mainly aimed at the application scenario of a dual-protocol QKD optical network based on BB84 and SNS, and solves the resource competition problem between the two quantum key distribution services and data communication services. This method fully considers the characteristics of the two protocols, and proposes an SNS wavelength allocation method based on link influence and a fiber core allocation method for reserved quantum cores, which can effectively improve the QKD performance in the network. The method proposed by the present invention helps to promote the development of quantum key distribution optical networks in which multiple protocols coexist, laying the foundation for their widespread application.

Description

Technical Field

[0001] This patent relates to the field of quantum communications, specifically the resource allocation problem in dual-protocol quantum key distribution (QKD) networks. This method addresses resource competition between two quantum key distribution services and data communication services in the network. By reducing the mutual influence of multi-link resources, it can effectively improve the key generation rate and further promote the practical application of QKD networks in which multiple protocols coexist. Background Art

[0002] Quantum Key Distribution (QKD), based on the three physical laws of quantum mechanics, can achieve confidential communications with information-theoretic security. Due to the extremely low power of quantum signals, in order to avoid noise interference from classical signals on quantum signals, early QKD networks were mostly based on dedicated optical fibers. This method not only requires a lot of financial and material resources, but also wastes network resources. Co-fiber transmission technology can reduce the waste of network resources caused by dedicated optical fibers. That is, through wavelength division multiplexing (WDM), classical signals and quantum signals can be multiplexed into the same optical fiber, which can improve the secure key generation rate (SKR) between point-to-point links. In the face of increasing transmission capacity requirements, multi-core fiber space division multiplexing (SDM) technology has been proposed in recent years to meet the growing business needs.

[0003] In order to provide secure communication services to more users in a wider spatial range, the technologies related to the integration of QKD and optical networks are also constantly developing. At present, the research on the coexistence of QKD and data communication services is mostly based on the BB84 protocol. In recent years, new protocols have been proposed and verified, among which different protocols have different characteristics, such as long-distance transmission capabilities, different resistance to noise, security performance, etc. Therefore, when faced with problems such as the diversity of business needs in the network, the QKD optical network composed of multiple protocols can give full play to the advantages of each protocol to provide better communication services. This patent mainly focuses on the dual-protocol QKD network composed of the most mature BB84 protocol and the Sending or Not Sending (SNS) protocol with high security, long-distance transmission characteristics, and support for asymmetric channels.

[0004] However, dual-protocol QKD optical networks face the following challenges: In multi-core QKD networks, spontaneous Raman scattering noise, four-wave mixing noise, and crosstalk noise between multi-core fibers can interfere with quantum signals, thereby affecting quantum key generation. Furthermore, the two quantum signals and the classical optical signal share limited wavelength resources, leading to resource competition among the three. With the continuous growth of high-bandwidth data communication services in the network, this resource competition problem will become increasingly severe. Furthermore, because the SNS protocol requires a third-party measurement node, SNS QKD transmission involves multiple links. Previous research has primarily focused on allocation algorithms for single-link transmission of quantum signals, failing to consider the potential for cross-link interference, which can reduce key generation rates.

[0005] To summarize, regarding the difficulties faced by the above dual-protocol QKD optical network, in dynamic business scenarios, how to reasonably allocate fiber core and wavelength resources for classical signals and quantum signals based on the different characteristics of the two protocols to improve the overall performance of the network is an urgent problem that needs to be solved. Summary of the Invention

[0006] This patent addresses the application scenario of quantum optical networks with dual protocols coexisting over multi-core optical fibers. To ensure a high SKR in the network, a resource allocation method based on link influence is designed for dual-protocol quantum optical networks. This method includes two key technical points: 1. A wavelength allocation method based on the SNS link influence is proposed; 2. A fiber core allocation method that reserves quantum cores for SNS quantum signals is proposed based on the noise resistance performance of the two protocols.

[0007] Regarding the first technical point, the specific explanation is as follows:

[0008] A wavelength allocation method based on the influence of SNS links is proposed. Considering that the SNS protocol involves multiple links, this patent defines the concept of influence to evaluate the degree of mutual influence of multiple links in resource allocation. The influence is the sum of the influence of the current node on other node pairs before and after the path is occupied. When allocating channels for SNS quantum signals, the wavelength λ j The influence degree under can be expressed as

[0009]

[0010] Among them, P a,b-related Represents all P a,b Node pairs P occupying the same link c,d The set of links for each pair of nodes is represented by P c,d express. Indicates the wavelength before the occupied channel λ j Next P c,d The number of available channels, It means that link l is occupied i Back wavelength λ j Next P c,d The number of available channels.

[0011] The calculation of influence is divided into the following steps:

[0012] Step 1: Determine the path of the currently assigned SNS node pair, record all links in the path, and put them into the set L;

[0013] Step 2: Record all node pairs involved in the links in L and put them into the set Nodes;

[0014] Step 3: Update the current remaining channel status and record the number of available channels for all node pairs in Nodes;

[0015] Step 4: Occupy the channels on each wavelength of the set L in turn. The sum of the changes in the number of available channels of the nodes in Nodes is the influence of the current wavelength.

[0016] The influence of each wavelength indicates the degree of impact on the entire network after the wavelength is occupied. Therefore, choosing a wavelength with a small influence can avoid wasting channel resources and improve the QKD performance of the network.

[0017] The second technical point is described in detail as follows:

[0018] This patent is aimed at dual-protocol coexistence quantum optical networks and proposes a fiber core allocation method that reserves quantum cores for SNS quantum signals. The key point of this technology is to reserve fiber cores for transmission of SNS quantum signals with poor noise resistance, which are defined as quantum cores. The purpose is to avoid interference of intra-core noise on SNS. Classical signals occupy the remaining cores. In order to avoid waste of resources, only single-link BB84 signals will occupy the wavelength fragments allocated after SNS and classical signals for transmission, and the remaining cores that transmit both classical signals and BB84 quantum signals are defined as hybrid cores. Therefore, the cores in multi-core optical fibers are divided into two types: quantum cores and hybrid cores.

[0019] The principle of allocating quantum cores and hybrid cores in the core allocation method is to maximize the distance between the quantum core and the hybrid core while ensuring that the number of hybrid cores adjacent to the quantum core is minimized. The steps of the core allocation method are:

[0020] Step 1: Select any core at the top of the multi-core optical fiber to be allocated and number it as 1;

[0021] Step 2: Draw a tangent line on the outermost side of core 1 and move it downward to pass through the center of core 1.

[0022] Named as the first priority grouping line;

[0023] Step 3: Move the first priority grouping line down so that it passes through the centers of multiple cores at the same time for the first time.

[0024] It is called the second priority grouping line, and moves down in sequence until the priority grouping line passes through the last core.

[0025] The division of all priority grouping lines is completed;

[0026] Step 4: Number the fiber cores. The core numbers of each priority group line are consecutive, and the priority order is: center > left > right;

[0027] Step 5: When selecting a quantum core, sort the numbers by priority from smallest to largest; when selecting a hybrid core, sort the numbers by priority from largest to smallest.

[0028] At the same time, this technical point proposes a quantum direct-pass method, that is, when the transmitted quantum signal passes through the direct-pass node, no reception, processing, or other operations are performed on the quantum signal, and the reception measurement is performed directly at the SNS receiving end. This takes into account the characteristics of SNS long-distance transmission and ensures that more node pairs can realize SNS QKD.

[0029] The method described in this patent can be used in multi-core dual-protocol QKD optical networks, effectively resolving the resource competition between quantum signals and classical data signals and improving the network's key generation capabilities. The implementation of this method can address issues such as the diversity of business security requirements in the network. Data services with different requirements can be encrypted using different QKD protocols. This method lays a foundation for promoting the development of QKD optical networks in which multiple protocols coexist. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 (a) is a schematic diagram of the BB84 protocol, (b) is a schematic diagram of the SNS protocol, and (c) is a schematic diagram of the SNS protocol with direct quantum signal transmission, where the dark arrows represent quantum channels and the light arrows represent data service channels.

[0031] Figure 2 Schematic diagram of influence calculation in the wavelength allocation method based on multi-link influence (taking a 6-node topology as an example).

[0032] Figure 3 Schematic diagram of the fiber core allocation method for reserving quantum cores (taking 19-core optical fiber as an example), where the dark-colored fiber cores are hybrid cores that simultaneously transmit quantum signals and classical light signals, and the light-colored fiber cores are quantum cores that only transmit quantum signals. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical methods and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] In the specific embodiment of this patent, taking a 6-node topology as an example, the present invention proposes the following Figure 2 The wavelength allocation method based on multi-link influence is shown, where the influence is calculated as follows:

[0035] Figure 2 In (a), the dark-colored nodes are nodes with SNS QKD receivers, and the arrows of different colors represent paths between different node pairs. When allocating resources to nodes 2 and 6, we need to calculate their multi-link influence. This path consists of two links. At this point, two more pairs of nodes are involved in this path (the path contains either line 1 or line 2). Therefore, when calculating the multi-link influence from node 2 to node 6, two links and three pairs of nodes are considered. Figure 2 (b) shows the number of available channels for each wavelength on each link. The available channels for a path are determined by the minimum channel value among all links in the path. It can be seen that the path from node 2 to node 6 currently has available channels at wavelengths λ1, λ3, and λ5. The links in this path are then occupied sequentially, and the impact on the three node pairs before and after occupation is calculated. Figure 2 (c) and (d) show the number of available channels remaining after link 1 and link 2 are occupied, respectively. Taking wavelength λ1 as an example, we can see that when link 1 is occupied, the number of available channels for the three node pairs remains unchanged, while when link 2 is occupied, the number of available channels for two node pairs decreases. Therefore, we can calculate the influence of wavelength λ1 as: 0 + 1 / 2 + 1 / 2 = 1, the influence of wavelength λ3 as: 1 + 1 + 1 + 1 = 4, and the influence of wavelength λ5 as: 1 / 2 + 1 / 2 + 1 / 2 + 1 / 2 = 2. Therefore, based on the influence, wavelength λ1 should be selected.

[0036] In the specific embodiment of this patent, a 19-core optical fiber is taken as an example. Figure 3 The core allocation method for reserved quantum cores shown in the figure is based on the principle of selecting quantum cores so that the distance between the quantum core and the hybrid core is maximized while ensuring that the number of hybrid cores adjacent to the quantum core is minimized. The specific process is as follows:

[0037] Randomly select one core from the top six cores of the 19-core regular hexagonal optical fiber to be allocated, and number it 1; draw a tangent line on the outermost side of core 1, and move it downward to pass through the center of core 1, and name it the first priority grouping line; move the priority grouping line down so that it passes through the centers of two cores at the same time for the first time, and name it the second priority grouping line, and move it down in sequence until the priority grouping line passes through the last core, and the division of all priority grouping lines is completed; the priority order of the core number of each priority grouping line is the core number, Figure 3 (Left) shows the result after numbering 19 cores; when selecting quantum cores, the numbers are sorted from small to large priority; when selecting hybrid cores, the numbers are sorted from large to small priority. Taking the case where the quantum core demand is 4 as an example, Figure 3 (Right) Shows the distribution of quantum cores and hybrid cores.

[0038] From the above examples, it can be seen that in the dual-protocol coexistence QKD optical network, this patent reasonably performs fiber core allocation based on the protocol characteristics, and on this basis, takes into account the multi-link characteristics of SNS, reduces the quantum signal blocking problem caused by the mutual influence of multiple links through channel allocation, improves the overall SKR of the network, and lays the foundation for the development of quantum optical networks where multiple protocols coexist.

Claims

1. A resource allocation method based on link influence in a dual-protocol quantum optical network aims to solve the resource allocation problem based on the different characteristics of the BB84 protocol and the Sending or Not Sending (SNS) protocol, improve the network quantum key distribution performance, and promote the development of quantum optical networks with coexistence of multiple protocols. The method is characterized by: It is mainly divided into two parts: A. A wavelength allocation method based on the influence of SNS links is proposed. Considering that the SNS protocol involves multiple links, the influence is used to evaluate the degree of mutual influence of each wavelength in resource allocation. Wavelengths with small influence are selected to allocate to quantum signals, thereby reducing the mutual influence of multiple links in the resource allocation process. B. A fiber core allocation method is proposed to reserve quantum cores for SNS quantum signals. Fiber cores reserved for SNS quantum signals with poor noise immunity are defined as quantum cores to prevent interference from intra-core noise on the SNS. Classical signals occupy the remaining cores. To avoid wasting resources, only a single-link BB84 signal is involved, which occupies the wavelength fragments allocated between the SNS and classical signals for transmission. The remaining cores, which transmit both classical and BB84 quantum signals, are defined as hybrid cores. Therefore, the cores in a multi-core fiber are divided into two types: Quantum core and hybrid core; the allocation principle of quantum core and hybrid core is to maximize the distance from quantum core to hybrid core while ensuring that the number of hybrid cores adjacent to the quantum core is minimized.

2. The method according to claim 1 proposes a wavelength allocation method based on the influence of SNS links, characterized in that: The influence degree is the sum of the influence of the current node on other node pairs before and after the path is occupied, which can be defined as Among them, P a,b-related Represents all P a,b Node pairs P occupying the same link c,d The set of links for each pair of nodes is represented by P c,d express, Indicates the wavelength before the occupied channel λ j Next P c,d The number of available channels, It means that link l is occupied i Back wavelength λ j Next P c,d The specific calculation process of the number of available channels includes the following steps: Step 1: Determine the path of the currently assigned SNS node pair, record all links in the path, and put them into the path link set; Step 2: Record all node pairs involved in the links in the path link set and put them into the node pair set; Step 3: Update the current remaining channel status and record the number of available channels for all node pairs in the node pair set; Step 4: Occupy the channels on each wavelength of the path link set in turn. The sum of the changes in the number of available channels is the influence of the current wavelength.

3. The method according to claim 1 proposes a fiber core allocation method for reserving quantum cores for SNS quantum signals, characterized in that: SNS quantum signals are only transmitted on quantum cores, and classical signals are only transmitted on hybrid cores. BB84 quantum signals can be transmitted on both types of cores. The specific method for allocating quantum cores and hybrid cores is as follows: Step 1: Select any core at the top of the multi-core optical fiber to be allocated and number it as 1; Step 2: Draw a tangent line on the outermost side of core 1 and move it downward to pass through the center of core 1. This line is named the first priority grouping line. Step 3: Move the first priority grouping line down so that it passes through the center of multiple cores at the same time for the first time. This is called the second priority grouping line. Move it down in sequence until the priority grouping line passes through the last core. The division of all priority grouping lines is completed. Step 4: Number the fiber cores. The core numbers of each priority group line are consecutive, and the priority order is: center > left > right. Step 5: When selecting a quantum core, sort the numbers by priority from smallest to largest; when selecting a hybrid core, sort the numbers by priority from largest to smallest.

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