Intelligent spectrum allocation method and system for adaptive signal-to-noise ratio in C+L optical networks

Abstract

This invention provides an intelligent spectrum allocation method and system for adaptive signal-to-noise ratio (SNR) in C+L band optical networks, relating to the field of optical fiber communication technology. The method includes: initializing the C+L band elastic optical network and determining nodes, links, spectrum slots, and time slot resources; receiving service requests and clarifying the source node, destination node, time slot requirements, and capacity; calculating link weights based on transmission distance and spectrum occupancy, and selecting the optimal path; determining the modulation format based on path distance and calculating the required spectrum slots; allocating higher-order modulation to the C band and lower-order modulation to the L band; ensuring continuous spectrum slots and consistent links, otherwise the request fails; selecting the spectrum block with the highest OSNR for allocation, comparing the OSNR with a threshold, and determining whether the request is successful. This invention improves the transmission quality of service requests and enables more comprehensive and accurate resource allocation.

Description

Technical Field

[0001] This invention relates to the field of optical fiber communication technology, and in particular to an intelligent spectrum allocation method and system for adaptive signal-to-noise ratio in C+L optical networks. Background Technology

[0002] With the rapid development of cloud computing, video technology, smart homes, and the Internet of Things (IoT), internet users' demand for bandwidth has surged, making it crucial to improve spectrum utilization and transmission efficiency. To meet this demand, wavelength division multiplexing (WDM)-based fiber optic transmission systems have been widely researched and applied. However, existing technologies still have shortcomings in these aspects and struggle to fully cope with the ever-increasing demand. The effective utilization of spectrum resources directly affects network operating efficiency and service quality; therefore, finding a more efficient resource allocation method has become an urgent problem to solve.

[0003] To further enhance the transmission capacity of optical fiber communication, C+L band elastic optical network transmission has been extended based on the existing C-band elastic optical network transmission. Previous studies have mainly focused on one-dimensional frequency domain routing and spectrum allocation, neglecting the time dimension. Therefore, it is necessary to design a two-dimensional time-frequency resource model to maintain resource state information in both the time and frequency domains.

[0004] Furthermore, as the spectral bandwidth and transmission distance of fiber optic links increase, the impact of ISRS (Inter-channel Stimulated Raman Scattering) on ​​fiber optic links becomes increasingly significant. Therefore, it is necessary to prioritize fiber optic links with more available continuous fiber optic systems and shorter transmission distances.

[0005] In summary, we currently face two major challenges. Firstly, addressing the neglected time-domain issues requires analyzing and maintaining link resource status within the established two-dimensional time-frequency resource model. Secondly, there is an urgent need to address users' demands for spectrum bandwidth and improve the utilization efficiency of spectrum resources. Summary of the Invention

[0006] To address this, embodiments of the present invention provide an intelligent spectrum allocation method and system for adaptive signal-to-noise ratio in C+L optical networks, which solves the problems of low transmission quality of service requests and low utilization efficiency of spectrum resources in the prior art.

[0007] To address the aforementioned problems, embodiments of the present invention provide an intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks, the method comprising:

[0008] Step S1: Initialize the C+L band elastic optical network. The initialization includes determining the set of nodes, the set of optical fiber links, the set of available spectrum slots in each optical fiber link, and the set of foreseeable time slots in the network.

[0009] Step S2: Generate a set of service requests, wherein the service requests include the source node, the destination node, the required number of time slots, and the capacity of the service requests;

[0010] Step S3: Calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, and select the path with the highest link weight as the working path for the service request.

[0011] Step S4: Determine the corresponding modulation format based on the actual physical transmission distance of the selected working path, and calculate the number of spectrum slots required for the service request;

[0012] Step S5: Determine whether the modulation format is a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, allocate it to the C-band for spectrum allocation; if it is a low-order modulation format, allocate it to the L-band for spectrum allocation.

[0013] Step S6: During the spectrum allocation process, determine whether the spectrum slots allocated to each service request are continuous and whether the same spectrum slots are allocated on all fiber links of the selected optical channel. If so, proceed to the next step; otherwise, the user request processing fails.

[0014] Step S7: For each service request, calculate the OSNR of the available spectrum block and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents the optical signal-to-noise ratio;

[0015] Step S8: Compare the OSNR corresponding to the modulation format adopted by the current service request with the preset threshold. If the OSNR is lower than the preset threshold, the service request is blocked immediately, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing succeeds.

[0016] Preferably, the method further includes: calculating relevant evaluation indicators after completing spectrum allocation to assess network performance.

[0017] Preferably, in step S3, the method of calculating the link weight of each path based on the transmission distance and spectrum occupancy status of the optical fiber link, and selecting the path with the highest link weight as the working path for the service request, specifically includes:

[0018] Step S31: Use the K shortest path algorithm to calculate the K paths between the source node and the destination node;

[0019] Step S32: Calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, where the link weight... Represented as:

[0020]

[0021] In the formula, Indicates the fiber optic transmission path p r The number of transmission nodes, where l represents the links in the selected path, if l∈p r Then x l Set the value to 1; This describes the fiber optic transmission path p. r The time-frequency continuity; This describes the distance of the fiber optic transmission path;

[0022] Step S33: Select the path with the highest link weight as the working path for business requests.

[0023] Preferably, the They are respectively:

[0024]

[0025] In the formula, |T| represents the total number of time slots; t represents the current time slot number; |F| represents the total number of spectrum slots; f represents the current spectrum slot number; L l Indicates the link distance within the selected path; Indicates the fiber optic transmission path p r The total transmission distance; Indicates the fiber optic transmission path p r The spectrum occupancy status is expressed as follows:

[0026]

[0027] in, This represents the inverted spectrum matrix, where 0 indicates an idle spectrum and 1 indicates a occupied spectrum.

[0028] Preferably, in step S4, the method for determining the corresponding modulation format based on the actual physical transmission distance of the selected working path and calculating the number of spectrum slots required for the service request specifically includes:

[0029] Step S41: Determine the corresponding modulation format and modulation level based on the actual physical transmission distance of the selected working path;

[0030] Step S42: Calculate the number of spectrum slots required for the service request based on the modulation level. r :

[0031]

[0032] In the formula, m represents the modulation level; Δ is the basic bandwidth of the spectral gap; C r This represents the size of the business request.

[0033] Preferably, in step S5, the method for determining whether the modulation format is a high-order modulation format or a low-order modulation format is as follows:

[0034] By calculating the average modulation format level M ave To determine whether the modulation format is a high-order modulation format or a low-order modulation format, when M ave When M is greater than the modulation level corresponding to the modulation format, the modulation format belongs to a higher-order modulation format; when M ave If the modulation level is less than the modulation level corresponding to the modulation format, then the modulation format belongs to a low-order modulation format; where M ave The calculation formula is:

[0035]

[0036] In the formula, m[i] represents the modulation level corresponding to the modulation format of the service request, and n represents the total number of modulation formats.

[0037] Preferably, in step S7, the method for calculating the OSNR of the available spectrum block is as follows:

[0038]

[0039] In the formula, P represents the transmit power of the service request r; This represents the amplified spontaneous emission noise power of the service request r; This represents the nonlinear noise power of the service request r; This indicates that the business request r is being interfered with by the self-channel; This indicates cross-channel interference in service request r; This represents the working path of the business request r from the source node s to the destination node d.

[0040] Preferably, step S7 further includes: for the C-band, using the last hit method for spectrum allocation; for the L-band, using the first hit method for spectrum allocation.

[0041] This invention also provides an intelligent spectrum allocation system for adaptive signal-to-noise ratio in C+L optical networks. This system is used to implement the aforementioned intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks, specifically including:

[0042] The network initialization module is used to initialize the C+L band elastic optical network. The initialization includes determining the set of nodes, the set of optical fiber links, the set of available spectral slots in each optical fiber link, and the set of foreseeable time slots in the network.

[0043] The business request generation module is used to generate a set of business requests, which include a source node, a destination node, the required number of time slots, and the capacity of the business request.

[0044] The path selection module is used to calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, and select the path with the highest link weight as the working path for the service request.

[0045] The modulation format determination and spectrum gap calculation module is used to determine the corresponding modulation format based on the actual physical transmission distance of the selected working path, and to calculate the number of spectrum gaps required for the service request.

[0046] The band selection module is used to determine whether the modulation format is a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, it is assigned to the C-band for spectrum allocation; if it is a low-order modulation format, it is assigned to the L-band for spectrum allocation.

[0047] The spectrum continuity and consistency check module is used to determine during the spectrum allocation process whether the spectrum slots allocated to each service request are continuous and whether the same spectrum slots are allocated on all fiber links of the selected optical channel. If so, proceed to the next step; otherwise, the user request processing fails.

[0048] The OSNR selection and spectrum allocation module is used to calculate the OSNR of the available spectrum block for each service request and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents the optical signal-to-noise ratio.

[0049] The OSNR threshold comparison and request processing module compares the OSNR corresponding to the modulation format adopted by the current service request with a preset threshold. If the OSNR is lower than the preset threshold, the service request is immediately blocked, i.e., the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing succeeds.

[0050] Preferably, the system further includes a performance evaluation module for calculating relevant evaluation indicators after spectrum allocation is completed, in order to evaluate network performance.

[0051] As can be seen from the above technical solutions, this invention application has the following beneficial effects:

[0052] (1) To achieve more comprehensive and accurate resource allocation, this invention employs a link weight calculation method that comprehensively considers resource fragmentation and transmission distance, and designs a two-dimensional time-frequency domain resource allocation model, thus improving upon the traditional single-spectrum-dimensional evaluation method. This link evaluation method can more comprehensively reflect the actual network resource requirements of each service request, reduce the impact of noise, thereby optimizing resource allocation, reducing resource waste, and improving resource utilization efficiency.

[0053] (2) To improve the transmission quality of service requests, this invention primarily optimizes for spontaneous emission noise and nonlinear noise. It reduces the ISRS impact between the C-band and L-band by adaptively adjusting the modulation format. Simultaneously, it searches for spectrum blocks with the highest signal-to-noise ratio (SNR) in all available spectrum resources to improve transmission quality. This adaptive SNR method more comprehensively reflects the mutual influence and constraints between the C+L bands on network resources, thereby optimizing transmission quality and reducing signal attenuation of service requests while improving resource utilization efficiency. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below. Referring to the accompanying drawings will provide a clearer understanding of the features and advantages of the present invention. The drawings are illustrative and should not be construed as limiting the present invention in any way. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort. Wherein:

[0055] Figure 1 This is a flowchart of an intelligent spectrum allocation method for adaptive signal-to-noise ratio in a C+L optical network, provided in the embodiments.

[0056] Figure 2 The fiber link weights in the elastic optical network based on a two-dimensional resource model are shown in the example. Calculation diagram;

[0057] Figure 3 This is a schematic diagram of the adaptive signal-to-noise ratio intelligent resource allocation method for service request R(1,4,2,50) in the embodiment.

[0058] Figure 4 This is a block diagram of an intelligent spectrum allocation system with adaptive signal-to-noise ratio for C+L optical networks, provided in the embodiment. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Example 1

[0061] To optimize the transmission quality of service requests and simultaneously maximize the time slot resources of the C+L band elastic optical network, such as... Figure 1 As shown in the figure, this invention proposes an intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks, the method comprising:

[0062] Step S1: Initialize the C+L band elastic optical network. Initialization includes determining the set of nodes, the set of fiber links, the set of available spectrum slots in each fiber link, and the set of foreseeable time slots in the network.

[0063] Step S2: Generate a set of business requests, which include the source node, destination node, required number of time slots, and the capacity of the business request;

[0064] Step S3: Calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, and select the path with the highest link weight as the working path for the service request.

[0065] Step S4: Determine the corresponding modulation format based on the actual physical transmission distance of the selected working path, and calculate the number of spectrum slots required for the service request;

[0066] Step S5: Determine whether the modulation format is a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, allocate it to the C-band for spectrum allocation; if it is a low-order modulation format, allocate it to the L-band for spectrum allocation.

[0067] Step S6: During the spectrum allocation process, determine whether the spectrum slots allocated to each service request are continuous and whether the same spectrum slots are allocated on all fiber links of the selected optical channel. If so, proceed to the next step; otherwise, the user request processing fails.

[0068] Step S7: For each service request, calculate the OSNR of the available spectrum block and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents the optical signal-to-noise ratio;

[0069] Step S8: Compare the OSNR corresponding to the modulation format adopted by the current service request with the preset threshold. If the OSNR is lower than the preset threshold, the service request is blocked immediately, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing succeeds.

[0070] As can be seen from the above technical solution, this invention proposes an intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks. By comprehensively considering the transmission distance of service requests, resource occupancy, and link weight, it selects the optimal path for transmission and automatically adjusts the spectrum allocation to the C or L band according to the modulation format. Simultaneously, it selects the spectrum block with the highest OSNR for allocation to ensure transmission quality. This method effectively improves time slot resource utilization and network adaptability, solves the fragmentation problem and noise impact in spectrum resource allocation, and maintains the efficient and stable operation of the network.

[0071] In step S1, the C+L band elastic optical network is initialized. Initialization includes determining the set of nodes, the set of fiber links, the set of available spectral slots in each fiber link, and the set of foreseeable time slots in the network. In this embodiment, the C+L band elastic optical network is represented by G(V, E, T, F), where V represents the set of nodes in the network, E represents a set of fiber links in the network, and T = {t1, t2, ..., t...} |T| Let F = {f1, f2, ..., f} represent the set of foreseeable timeslots in the network. |F|} represents the set of available spectrum slots in each fiber optic link.

[0072] In step S2, a set of service requests is generated. Each service request includes the source node, destination node, required number of time slots, and the capacity of the service request. In this embodiment, R represents a set of connection requests, and the service request is denoted by r(s, d, t, C). r )∈R(s,d,t,C r This represents a service request from source node s to destination node d, requiring t time slots and having a service request capacity of C. r .

[0073] In step S3, the link weight of each path is calculated based on the transmission distance and spectrum occupancy status of the fiber optic link, and the path with the highest link weight is selected as the working path for the service request. Specifically, this includes:

[0074] Step S31: Use the K shortest path algorithm to calculate the K paths between the source node and the destination node.

[0075] Step S32: Calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, where the link weight... Represented as:

[0076]

[0077] In the formula, Indicates the fiber optic transmission path p r The number of transmission nodes, where l represents the links in the selected path, if l∈p r Then x l Set the value to 1; This describes the fiber optic transmission path p. r The time-frequency continuity; This describes the distance of the fiber optic transmission path; where They are respectively:

[0078]

[0079] In the formula, |T| represents the total number of time slots; t represents the current time slot number; |F| represents the total number of spectrum slots; f represents the current spectrum slot number; L l Indicates the link distance within the selected path; Indicates the fiber optic transmission path p r The total transmission distance; Indicates the fiber optic transmission path p r The spectrum occupancy status is expressed as follows:

[0080]

[0081] in, This represents the inverted spectrum matrix, where 0 indicates an idle spectrum and 1 indicates a occupied spectrum.

[0082] Step S33: Select the path with the highest link weight as the working path for business requests.

[0083] As the number of frequency slots occupied by fiber optic links increases and the transmission distance of fiber optic links increases, the impact of ISRS on fiber optic links also becomes increasingly significant. Therefore, this invention proposes a method for calculating fiber optic link weights that considers the transmission distance of the fiber optic link and the status of all available spectrum blocks for receiving service requests. If a working path cannot be established, the service request is blocked. When a high-priority path is blocked on a certain segment of the link, lower-priority paths are sequentially selected for spectrum resource allocation until resource allocation is successful or all paths are blocked. This algorithm increases network flexibility, reduces network congestion, and improves utilization.

[0084] In step S4, the corresponding modulation format is determined based on the actual physical transmission distance of the selected working path, and the number of spectrum slots required for the service request is calculated, specifically including:

[0085] Step S41: Determine the corresponding modulation format and modulation level based on the actual physical transmission distance of the selected working path. See Table 1 below.

[0086] Step S42: Calculate the number of spectrum slots required for the service request based on the modulation level. r :

[0087]

[0088] In the formula, m represents the modulation level; Δ is the basic bandwidth of the spectral gap, with a value of 12.5 Gbps; C r This represents the size of the business request.

[0089] Table 1. Transmission distance and OSNR threshold corresponding to modulation formats.

[0090]

[0091] In step S5, it is determined whether the modulation format is a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, it is assigned to the C-band for spectrum allocation; if it is a low-order modulation format, it is assigned to the L-band for spectrum allocation.

[0092] Since the C-band in the elastic optical network causes an increase in the impact of ISRS on the L-band, this invention allocates higher-order modulation formats to the C-band to reduce the spectrum occupancy of the C-band, while preferentially allocating lower-order modulation formats to the L-band.

[0093] Furthermore, this invention employs an adaptive method based on transmission distance to select the modulation format, as shown in Table 1. The method for determining whether the modulation format is a high-order or low-order modulation format is as follows:

[0094] By calculating the average modulation format level M ave To determine whether the modulation format is a high-order or low-order modulation format, when M ave When M is greater than the modulation level corresponding to the modulation format, the modulation format belongs to a higher-order modulation format; when M ave When the modulation level is less than the modulation level corresponding to the modulation format, the modulation format belongs to a low-order modulation format; where M ave The calculation formula is:

[0095]

[0096] In the formula, m[i] represents the modulation level corresponding to the modulation format of the service request, and n represents the total number of modulation formats.

[0097] In step S6, in the C+L band flexible optical network, spectrum allocation must meet two constraints: spectrum continuity and spectrum consistency. Specifically, during the spectrum allocation process, it is necessary to determine whether the spectrum slots allocated to each service request are continuous (i.e., spectrum continuity) and whether the same spectrum slots are allocated on all fiber links of the selected optical channel (i.e., spectrum consistency). If so, proceed to the next step; otherwise, the user request processing fails.

[0098] In step S7, for each service request, the OSNR of the available spectrum block is calculated, and the spectrum block with the highest OSNR is selected for spectrum allocation, where OSNR represents the optical signal-to-noise ratio.

[0099] Specifically, in the frequency domain, for applications using low-order modulation formats in the L-band, it is necessary to comprehensively evaluate the availability of all spectral blocks and accurately calculate their optical signal-to-noise ratio (OSNR). This invention proposes a solution: deploying erbium-doped fiber amplifiers (EDFAs) at regular intervals on the fiber optic links connecting node pairs to effectively compensate for signal attenuation during fiber transmission. However, this solution is accompanied by the generation of amplified spontaneous emission noise (ASE). Furthermore, the dominant factors contributing to OSNR reduction in C+L band flexible optical networks are analyzed in detail, especially nonlinear interference (NLI) caused by interband interactions.

[0100] Assume that the transmit power of each service request r is the same, denoted as P, and that the loss of the fiber optic link is fully compensated by EDFA. This represents the amplified spontaneous emission noise (ASE) power of service request r. The nonlinear noise (NLI) power of the service request r is represented by the following formula for calculating OSNR:

[0101]

[0102] Self-channel interference (SCI) and cross-channel interference (XCI) are two major types of interference in optical communication systems. SCI originates from signal interference within the same channel, while XCI involves mutual interference between different channels. The calculated OSNR values ​​are organized in a priority queue, with the spectrum block having the highest OSNR being selected first, and a first-hit strategy is used for spectrum allocation.

[0103] In contrast, when using higher-order modulation formats in the C-band, a last-hit strategy is employed for spectrum allocation. The advantage of this strategy is that it maintains the compactness of spectrum slot usage; when a service request terminates and the spectrum is released, the released spectrum resources are relatively continuous. This makes it easier to meet spectrum continuity requirements for subsequent service requests, thereby improving the availability of spectrum resources. Simultaneously, this strategy can also mitigate the impact of the C-band on the ISRS of the L-band, improving the OSNR tolerance.

[0104] In step S8, the OSNR corresponding to the modulation format adopted by the current service request is compared with a preset threshold. If the OSNR is lower than the preset threshold, the service request is immediately blocked, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing succeeds.

[0105] In addition, the method also includes: after completing spectrum allocation, calculating relevant evaluation indicators to assess network performance and provide a basis for subsequent optimization and improvement.

[0106] To further illustrate the advantages of this invention, specific experiments will be conducted below.

[0107] To minimize the time slot resource consumption of a set of service requests, the C+L band elastic optical network G(V,E,T,F) is first initialized, including network topology information, fiber link wavelengths, and two-dimensional time-frequency resources. Second, a set of service requests is generated, including the source node, destination node, capacity requirements, and time slot requirements. Finally, based on the fiber link weighting value, spectrum is adaptively and intelligently allocated to achieve optimal spectrum resource utilization. The details are as follows:

[0108] First, Figure 2 (a) shows the network topology diagram of 4 nodes. The values ​​on the fiber optic links represent the physical distance of the links in km. The base bandwidth of each spectrum slot is set to 12.5 GHz. The number of frequency domain slots on each fiber optic link is 100 and the number of time domain slots is 20. The capacity range of the generated requests is 1-300 Gbps, and different modulation format levels are used respectively.

[0109] Second, generate a set of service requests R(1,4,2,50). R represents a service request from source node s to destination node d, requiring 2 time slots, and the service request capacity is 50Gbps.

[0110] third, Figure 2 This demonstrates the link weights calculated based on a two-dimensional time-frequency resource model. An example of route optimization. In this example, Figure 2 (a) shows that when a business request arrives at the destination node 4 from the source node 1, there are three candidate paths: candidate path 1 (1->3->4), candidate path 2 (1->4), and candidate path 3 (1->2->4). Figure 2 (b), (c), and (d) show the resource occupancy status of the three candidate paths, respectively. The state matrices of the three candidate paths, derived from equation (4), are shown in equations (9), (10), and (11), respectively.

[0111]

[0112] like Figure 2 As shown, using the state matrices of the three candidate paths above, and formulas (1), (2), and (3), the link weight of candidate path 1 is calculated as: LW p1 =0.0010; Link weight of candidate path 2: LW p2 =0.0017; Link weight of candidate path 3: LW p3 =0.0023. Comparing the weights of the three links, because the LW of path 3... p1 Since the value is the largest, path 3 is chosen for resource allocation. This selection takes into account both the fragmentation of resource allocation within the path and the need to control the fiber optic link transmission distance to reduce the impact of ISRS on signal transmission.

[0113] Fourth, based on the total transmission distance of the selected path 3 being 300km, the modulation format in the service request resource allocation process is 16-QAM, with modulation level m=4. The number of spectrum slots required for the service request is calculated using formula (5). r =1.

[0114] Fifth, the average modulation format level is calculated using formula (6). BPSK and QPSK are low-order modulation formats, while 8-QAM and 16-QAM are high-order modulation formats. Given that the total transmission distance of the selected path 3 is 300km, the modulation format used in the service request resource allocation process is 16-QAM with modulation level m=4. Therefore, spectrum allocation should be performed in the C-band. This selection is made to reduce ISRS interference between the C-band and L-band.

[0115] sixth, Figure 3 An adaptive signal-to-noise ratio (SNR) spectrum allocation method is demonstrated. When a service request R(1,4,2,50) arrives and spectrum is allocated on the C-band of path 3, the SNRs (Optical Signal-to-Noise Ratios) of the two available spectrum blocks A and B, calculated by formulas (7) and (8), are 15 dB and 13 dB, respectively. A higher SNR indicates higher transmission quality of the service request in the link. The SNR value reflects the impact of noise generated during the transmission of the service request on the initial signal, and simultaneously considers amplified spontaneous emission noise and nonlinear noise, thereby optimizing the transmission quality of network resources.

[0116] Example 2

[0117] like Figure 4 As shown, this invention provides an intelligent spectrum allocation system for adaptive signal-to-noise ratio in C+L optical networks. This system is used to implement the intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks described in Embodiment 1 above, specifically including:

[0118] The network initialization module is used to initialize the C+L band elastic optical network. The initialization includes determining the set of nodes, the set of optical fiber links, the set of available spectrum slots in each optical fiber link, and the set of foreseeable time slots in the network.

[0119] The business request generation module is used to generate a set of business requests, which include the source node, destination node, required number of time slots, and the capacity of the business request.

[0120] The path selection module is used to calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, and select the path with the highest link weight as the working path for the service request.

[0121] The modulation format determination and spectrum gap calculation module is used to determine the corresponding modulation format based on the actual physical transmission distance of the selected working path, and to calculate the number of spectrum gaps required for the service request.

[0122] The band selection module is used to determine whether the modulation format is a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, it is assigned to the C-band for spectrum allocation; if it is a low-order modulation format, it is assigned to the L-band for spectrum allocation.

[0123] The spectrum continuity and consistency check module is used to determine during the spectrum allocation process whether the spectrum slots allocated to each service request are continuous and whether the same spectrum slots are allocated on all fiber links of the selected optical channel. If so, proceed to the next step; otherwise, the user request processing fails.

[0124] The OSNR selection and spectrum allocation module is used to calculate the OSNR of the available spectrum block for each service request and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents the optical signal-to-noise ratio.

[0125] The OSNR threshold comparison and request processing module compares the OSNR corresponding to the modulation format adopted by the current service request with a preset threshold. If the OSNR is lower than the preset threshold, the service request is immediately blocked, i.e., the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing succeeds.

[0126] In addition, the system also includes a performance evaluation module, which calculates relevant evaluation metrics to assess network performance after spectrum allocation is completed.

[0127] This embodiment presents an intelligent spectrum allocation system for adaptive signal-to-noise ratio in C+L optical networks, used to implement the aforementioned intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks. Therefore, the specific implementation of the intelligent spectrum allocation system for adaptive signal-to-noise ratio in C+L optical networks can be found in the previous section on the embodiment of the intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks. To avoid redundancy, it will not be repeated here.

[0128] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0129] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0130] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0131] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A smart spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks, characterized in that, include: Step S1: Initialize the C+L band elastic optical network. The initialization includes determining the set of nodes, the set of optical fiber links, the set of available spectrum slots in each optical fiber link, and the set of foreseeable time slots in the network. Step S2: Generate a set of service requests, wherein the service requests include the source node, the destination node, the required number of time slots, and the capacity of the service requests; Step S3: Calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, and select the path with the highest link weight as the working path for the service request. Specifically, this includes: Step S31: Use the K shortest path algorithm to calculate the K paths between the source node and the destination node; Step S32: Calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, where the link weight... Represented as: （1） In the formula, Indicates the fiber optic transmission path The number of transmission nodes, Indicates the links in the selected path, if ,but Set the value to 1; This describes the fiber optic transmission path. The time-frequency continuity; This describes the distance of the fiber optic transmission path; Step S33: Select the path with the highest link weight as the working path for the business request; The above , They are respectively: （2） （3） In the formula, Indicates the total number of time slots; Indicates the current time slot number; Indicates the total number of spectrum gaps; Indicates the current spectrum slot number; Indicates the link distance within the selected path; Indicates the fiber optic transmission path The total transmission distance; Indicates the fiber optic transmission path The spectrum occupancy status is expressed as follows: （4） in, This represents the inverted spectrum matrix, where 0 indicates an idle spectrum and 1 indicates a occupied spectrum. Step S4: Determine the corresponding modulation format based on the actual physical transmission distance of the selected working path, and calculate the number of spectrum slots required for the service request; Step S5: Determine whether the modulation format is a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, allocate it to the C-band for spectrum allocation; if it is a low-order modulation format, allocate it to the L-band for spectrum allocation. Step S6: During the spectrum allocation process, determine whether the spectrum slots allocated to each service request are continuous and whether the same spectrum slots are allocated on all fiber links of the selected optical channel. If so, proceed to the next step; otherwise, the user request processing fails. Step S7: For each service request, calculate the OSNR of the available spectrum block and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents the optical signal-to-noise ratio; Step S8: Compare the OSNR corresponding to the modulation format adopted by the current service request with the preset threshold. If the OSNR is lower than the preset threshold, the service request is blocked immediately, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing succeeds.

2. The intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks according to claim 1, characterized in that, The method further includes: calculating relevant evaluation metrics after spectrum allocation is completed to assess network performance.

3. The intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks according to claim 1, characterized in that, In step S4, the method for determining the corresponding modulation format based on the actual physical transmission distance of the selected working path and calculating the number of spectrum slots required for the service request specifically includes: Step S41: Determine the corresponding modulation format and modulation level based on the actual physical transmission distance of the selected working path; Step S42: Calculate the number of spectrum slots required for the service request based on the modulation level. : （5） In the formula, Indicates the modulation level; It is the basic bandwidth of the spectrum gap; This represents the size of the business request.

4. The intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks according to claim 1, characterized in that, In step S5, the method for determining whether the modulation format is a high-order modulation format or a low-order modulation format is as follows: By calculating the average modulation format level To determine whether the modulation format is a high-order modulation format or a low-order modulation format, when... When the modulation level is greater than the modulation level corresponding to the modulation format, then the modulation format belongs to a higher-order modulation format; when If the modulation level is less than the modulation level corresponding to the modulation format, then the modulation format belongs to a low-order modulation format; wherein The calculation formula is: （6） In the formula, This indicates the modulation level corresponding to the modulation format of the service request. This indicates the total number of modulation formats.

5. The intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks according to claim 1, characterized in that, In step S7, the method for calculating the OSNR of the available spectrum block is as follows: （7） （8） In the formula, Indicates a business request The transmission power; Indicates a business request The amplified spontaneous emission noise power; Indicates a business request The nonlinear noise power; Indicates a business request The interference of self-confidence; Indicates a business request Cross-channel interference; Indicates a business request From the source node to the destination node The working path.

6. The intelligent spectrum allocation method for adaptive signal-to-noise ratio in C+L optical networks according to claim 1, characterized in that, Step S7 further includes: for the C-band, the last hit method is used for spectrum allocation; for the L-band, the first hit method is used for spectrum allocation.

7. An intelligent spectrum allocation system for C+L optical networks with adaptive signal-to-noise ratio, characterized in that, The system is used to implement the intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical networks as described in any one of claims 1 to 6, specifically including: The network initialization module is used to initialize the C+L band elastic optical network. The initialization includes determining the set of nodes, the set of optical fiber links, the set of available spectral slots in each optical fiber link, and the set of foreseeable time slots in the network. The business request generation module is used to generate a set of business requests, which include a source node, a destination node, the required number of time slots, and the capacity of the business request. The path selection module is used to calculate the link weight of each path based on the transmission distance and spectrum occupancy status of the fiber optic link, and select the path with the highest link weight as the working path for the service request. The modulation format determination and spectrum gap calculation module is used to determine the corresponding modulation format based on the actual physical transmission distance of the selected working path, and to calculate the number of spectrum gaps required for the service request. The band selection module is used to determine whether the modulation format is a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, it is assigned to the C-band for spectrum allocation; if it is a low-order modulation format, it is assigned to the L-band for spectrum allocation. The spectrum continuity and consistency check module is used to determine during the spectrum allocation process whether the spectrum slots allocated to each service request are continuous and whether the same spectrum slots are allocated on all fiber links of the selected optical channel. If so, proceed to the next step; otherwise, the user request processing fails. The OSNR selection and spectrum allocation module is used to calculate the OSNR of the available spectrum block for each service request and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents the optical signal-to-noise ratio. The OSNR threshold comparison and request processing module compares the OSNR corresponding to the modulation format adopted by the current service request with a preset threshold. If the OSNR is lower than the preset threshold, the service request is immediately blocked, i.e., the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing succeeds.

8. The intelligent spectrum allocation system for adaptive signal-to-noise ratio in C+L optical networks according to claim 7, characterized in that, The system also includes a performance evaluation module, which calculates relevant evaluation metrics after spectrum allocation is completed to assess network performance.

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