Intelligent spectrum allocation method and system for self-adaptive signal-to-noise ratio of C + L optical network

Abstract

The invention provides an intelligent spectrum allocation method and system for a self-adaptive signal-to-noise ratio of a C + L optical network, and relates to the technical field of optical fiber communication, and the method comprises the steps: initializing a C + L wave band elastic optical network, and determining nodes, links, spectrum slots and time slot resources; receiving a service request, and defining a source node, a destination node, time slot requirements and capacities; calculating a link weight according to a transmission distance and spectrum occupation, and selecting an optimal path; determining a modulation format according to the path distance, and calculating a required spectrum gap; high-order modulation is allocated to a C wave band, and low-order modulation is allocated to an L wave band; ensuring that spectrum slots are continuous and links are consistent, otherwise, the request fails; and selecting the spectrum block distribution with the highest OSNR, comparing the OSNR with a threshold value, and determining whether the request is successful or not. According to the invention, the transmission quality of the service request is improved, and resource allocation can be carried out more comprehensively and accurately.

Description

Technical Field

[0001] The present 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 of a C+L optical network. Background Art

[0002] With the rapid development of cloud computing, video technology, smart home and Internet of Things (IoT) technology, the demand for bandwidth from Internet users has increased dramatically, making it essential to improve spectrum utilization efficiency and transmission efficiency. To meet this demand, optical fiber transmission systems based on wavelength division multiplexing (WDM) have been widely studied and applied. However, the performance of existing technologies in these aspects is still insufficient and it is difficult to fully cope with the growing demand. The effective use of spectrum resources is directly related to the operating efficiency and service quality of the network. Therefore, finding a more efficient resource allocation method has become an urgent problem to be solved.

[0003] In order to further improve the transmission capacity of optical fiber communication, based on the existing C-band elastic optical network transmission, the C+L band elastic optical network transmission is expanded. Previous research has mainly focused on routing and spectrum allocation in the one-dimensional frequency domain, while ignoring the time dimension. Therefore, it is necessary to design a two-dimensional time-frequency resource model to maintain resource status information in both the time domain and the frequency domain.

[0004] In addition, as the spectrum bandwidth and transmission distance occupied by the optical fiber link increase, the impact of ISRS (Inter-channel Stimulated Raman Scattering) on ​​the optical fiber link becomes increasingly significant. Therefore, it is necessary to give priority to optical fiber links with more available continuous optical fiber systems and shorter transmission distances.

[0005] In summary, there are two major challenges. On the one hand, in order to address the neglected time domain issues, it is necessary to analyze and maintain the link resource status on the established two-dimensional time-frequency resource model. On the other hand, it is urgent to address the user's demand for spectrum bandwidth and improve the utilization efficiency of spectrum resources. Summary of the invention

[0006] To this end, the embodiments of the present invention provide a C+L optical network adaptive signal-to-noise ratio intelligent spectrum allocation method and system, which are used to solve the problems of low transmission quality of service requests and low utilization efficiency of spectrum resources in the prior art.

[0007] In order to solve the above problem, an embodiment of the present invention provides an intelligent spectrum allocation method for adaptive signal-to-noise ratio of a C+L optical network, the method comprising:

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

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

[0010] Step S3: Calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, and select the path with the highest link weight as the working path for the service request;

[0011] Step S4: determining a corresponding modulation format according to an actual physical transmission distance of the selected working path, and calculating the number of spectrum slots required for the service request;

[0012] Step S5: determining whether the modulation format is a high-order modulation format or a low-order modulation format; if it is a high-order modulation format, allocating it to the C band for spectrum allocation; if it is a low-order modulation format, allocating 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 the same spectrum slots are allocated on all optical fiber links of the selected optical channel. If yes, 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 blocks, and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents 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 immediately blocked, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing is successful.

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

[0017] Preferably, in step S3, the method of calculating the link weight of each path according to 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: using a K shortest path algorithm to calculate K paths from a source node to a destination node;

[0019] Step S32: Calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, where the link weight It is expressed as:

[0020]

[0021] In the formula, represents the optical fiber transmission path p r The number of transmission nodes, l represents the link in the selected path, if l∈p r , then x l The value of is set to 1; Indicates the description of the optical fiber transmission path p r The time-frequency continuity of It describes the distance of the optical fiber transmission path;

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

[0023] Preferably, the They are:

[0024]

[0025] Where |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 represents the link distance in the selected path; represents the optical fiber transmission path p r The total transmission distance; represents the optical fiber transmission path p r The spectrum occupancy is expressed as:

[0026]

[0027] in, Represents the matrix after the spectrum matrix is ​​inverted, that is, the spectrum state is 0 when it is idle and 1 when it is occupied.

[0028] Preferably, in step S4, the method of determining the corresponding modulation format according to 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: determining a corresponding modulation format and modulation level according to an actual physical transmission distance of the selected working path;

[0030] Step S42: Calculate the number of spectrum slots required for the service request according to the modulation level r :

[0031]

[0032] Where m represents the modulation level; Δ is the basic bandwidth of the spectrum slot; C r Indicates the capacity 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:

[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 high-order modulation format; when M ave When M is less than the modulation level corresponding to the modulation format, the modulation format belongs to a low-order modulation format; ave The calculation formula is:

[0035]

[0036] In the formula, m[i] represents the modulation level corresponding to the modulation format requested by the service, 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:

[0038]

[0039] Where P represents the transmission power of service request r; represents the amplified spontaneous emission noise power of service request r; represents the nonlinear noise power of the service request r; represents the self-channel interference of service request r; represents the cross-channel interference of service request r; Represents the working path of service request r from source node s to destination node d.

[0040] Preferably, the step S7 further comprises: for the C band, using the last hit method to allocate the spectrum; for the L band, using the first hit method to allocate the spectrum.

[0041] The embodiment of the present invention further provides an intelligent spectrum allocation system for adaptive signal-to-noise ratio of a C+L optical network, which is used to implement the intelligent spectrum allocation method for adaptive signal-to-noise ratio of a C+L optical network, and specifically includes:

[0042] A network initialization module, used to initialize the C+L band elastic optical network, wherein the initialization includes determining a set of nodes in the network, a set of optical fiber links, a set of available spectrum slots in each optical fiber link, and a set of foreseeable time slots in the network;

[0043] A service request generation module, used to generate a set of service requests, wherein the service request includes a source node, a destination node, a required number of time slots, and a capacity size of the service request;

[0044] A path selection module is used to calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, and select the path with the highest link weight as the working path for the service request;

[0045] A modulation format determination and spectrum slot calculation module, used to determine the corresponding modulation format according to the actual physical transmission distance of the selected working path, and calculate the number of spectrum slots required for the service request;

[0046] A band selection module, used to determine whether the modulation format is a high-order modulation format or a low-order modulation format, and 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;

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

[0048] An OSNR selection and spectrum allocation module, for calculating the OSNR of available spectrum blocks for each service request, and selecting the spectrum block with the highest OSNR for spectrum allocation, wherein OSNR represents optical signal-to-noise ratio;

[0049] The OSNR threshold comparison and request processing module is used to 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 immediately blocked, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing is successful.

[0050] Preferably, the system further comprises a performance evaluation module, which is used to calculate relevant evaluation indicators to evaluate network performance after spectrum allocation is completed.

[0051] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0052] (1) In order to allocate resources more comprehensively and accurately, the present invention adopts a link weight calculation method that comprehensively considers the fragmentation of resource allocation and the transmission distance, designs a two-dimensional time-frequency domain resource allocation model, and improves the traditional single spectrum dimension evaluation method. This link evaluation method can more comprehensively reflect the actual demand for network resources of each service request, reduce the impact of noise, thereby optimizing resource allocation, reducing resource waste, and improving resource utilization efficiency.

[0053] (2) In order to improve the transmission quality of service requests, the present invention mainly optimizes the spontaneous emission noise and nonlinear noise, reduces the ISRS impact between the C band and the L band by adaptively adjusting the modulation format, and at the same time, searches for spectrum blocks that are conducive to improving transmission quality in all available spectrum resource spaces, that is, selects the spectrum block space with the maximum signal-to-noise ratio. This adaptive signal-to-noise ratio method can more comprehensively reflect the mutual influence and restriction between the C+L bands on network resources, thereby optimizing the transmission quality and reducing the attenuation of service request signals while improving resource utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the implementation cases of the present invention or the technical solutions in the prior art, the following is a brief description of the drawings required for use in the embodiments. By referring to the drawings, the features and advantages of the present invention will be more clearly understood. The drawings are schematic and should not be understood as limiting the present invention in any way. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0055] Figure 1 A flowchart of an intelligent spectrum allocation method for adaptive signal-to-noise ratio of a C+L optical network provided in an embodiment;

[0056] Figure 2 The fiber link weight of the elastic optical network based on the two-dimensional resource model in the embodiment Calculation diagram;

[0057] Figure 3 Schematic diagram of an adaptive signal-to-noise ratio intelligent resource allocation method for service request R(1,4,2,50) in an embodiment;

[0058] Figure 4 It is a block diagram of an intelligent spectrum allocation system with adaptive signal-to-noise ratio for a C+L optical network provided in an embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] Embodiment 1

[0061] In order to optimize the transmission quality of service requests and optimize the time slot resources of the C+L band elastic optical network. Figure 1 As shown, an embodiment of the present invention proposes an intelligent spectrum allocation method for adaptive signal-to-noise ratio of a C+L optical network, the method comprising:

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

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

[0064] Step S3: Calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, and select the path with the highest link weight as the working path for the service request;

[0065] Step S4: determining a corresponding modulation format according to an actual physical transmission distance of the selected working path, and calculating the number of spectrum slots required for the service request;

[0066] Step S5: determining whether the modulation format is a high-order modulation format or a low-order modulation format; if it is a high-order modulation format, allocating it to the C band for spectrum allocation; if it is a low-order modulation format, allocating 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 the same spectrum slots are allocated on all optical fiber links of the selected optical channel. If yes, 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 blocks, and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents 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 immediately blocked, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing is successful.

[0070] From the above technical solution, it can be seen that the present invention proposes an intelligent spectrum allocation method for C+L optical network adaptive signal-to-noise ratio, which comprehensively considers the transmission distance, resource occupancy and link weight of the service request, selects the optimal path for transmission, and automatically adjusts the spectrum allocation to the C or L band according to the modulation format, and selects the spectrum block with the highest OSNR for allocation to ensure the transmission quality. This method effectively improves the time slot resource utilization and network adaptability, solves the fragmentation problem and noise influence 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. The initialization includes determining a set of nodes in the network, a set of optical fiber links, a set of available spectrum slots in each optical fiber link, and a 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 a set of nodes in the network, E represents a set of optical fiber links in the network, and T={t 1 , t 2 , ..., t |T|} represents the set of foreseeable time slots in the network, F = {f 1 , f 2 , ..., f |F|} represents the set of available spectrum slots in each optical fiber link.

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

[0073] In step S3, the link weight of each path is calculated according to the transmission distance and spectrum occupancy status of the optical fiber link, and the path with the highest link weight is selected as the working path for the service request, which specifically includes:

[0074] Step S31: using a K shortest path algorithm to calculate K paths from a source node to a destination node.

[0075] Step S32: Calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, where the link weight It is expressed as:

[0076]

[0077] In the formula, represents the optical fiber transmission path p r The number of transmission nodes, l represents the link in the selected path, if l∈p r , then x l The value of is set to 1; Indicates the description of the optical fiber transmission path p r The time-frequency continuity of It describes the distance of the optical fiber transmission path; They are:

[0078]

[0079] Where |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 represents the link distance in the selected path; represents the optical fiber transmission path p r The total transmission distance; represents the optical fiber transmission path p r The spectrum occupancy is expressed as:

[0080]

[0081] in, Represents the matrix after the spectrum matrix is ​​inverted, that is, the spectrum state is 0 when it is idle and 1 when it is occupied.

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

[0083] As the number of frequency slots occupied by optical fiber links increases and the transmission distance of optical fiber links increases, the impact of ISRS on optical fiber links becomes increasingly greater. Therefore, the present invention proposes a method for calculating the weight of optical fiber links that takes into account the transmission distance of optical fiber links 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 path with a high priority is blocked on a certain link section, paths with lower priorities are selected in turn for spectrum resource allocation until the resource allocation is successful or all paths are blocked. The algorithm increases the flexibility of the network, reduces network congestion, and improves utilization.

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

[0085] Step S41: Determine the corresponding modulation format and modulation level according to the actual physical transmission distance of the selected working path, as shown in Table 1 below.

[0086] Step S42: Calculate the number of spectrum slots required for the service request according to the modulation level r :

[0087]

[0088] Where m represents the modulation level; Δ is the basic bandwidth of the spectrum slot, which is 12.5 Gbps; C r Indicates the capacity of the business request.

[0089] Table 1 Transmission distance and OSNR threshold corresponding to the modulation format

[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 allocated to the C band for spectrum allocation; if it is a low-order modulation format, it is allocated to the L band for spectrum allocation.

[0092] Since the C-band in the elastic optical network causes an increased impact of ISRS on the L-band, the present invention allocates high-order modulation formats to the C-band to reduce the spectrum occupancy of the C-band, and preferentially allocates low-order modulation formats to the L-band.

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

[0094] 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 high-order modulation format; when M ave When M is less than the modulation level corresponding to the modulation format, the modulation format belongs to a low-order modulation format; ave The calculation formula is:

[0095]

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

[0097] In step S6, in the C+L band elastic optical network, spectrum allocation must meet two constraints: spectrum continuity and spectrum consistency. Specifically, in 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 the same spectrum slots are allocated on all optical fiber links of the selected optical channel (i.e., spectrum consistency). If yes, the next step is executed, otherwise, the user request processing fails.

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

[0099] Specifically, in the frequency domain dimension, for the application scenarios using low-order modulation formats in the L-band, it is necessary to comprehensively evaluate the availability of all spectrum blocks and accurately calculate their optical signal-to-noise ratio (OSNR). The present invention proposes a solution, namely, deploying erbium-doped fiber amplifiers (EDFA) at certain intervals on the optical fiber link connecting the node pairs to effectively compensate for the signal attenuation in optical fiber transmission. However, this solution is accompanied by the generation of amplified spontaneous emission noise (ASE). In addition, the dominant factors of OSNR reduction in C+L band elastic optical networks are analyzed in detail, especially the nonlinear interference (NLI) caused by inter-band interactions.

[0100] Assume that the transmission power of each service request r is the same, denoted as P, and the loss of the optical fiber link is fully compensated by the EDFA. represents the amplified spontaneous emission (ASE) power of the service request r, The nonlinear noise (NLI) power of the service request r is expressed as follows:

[0101]

[0102] Among them, self-channel interference (SCI) and cross-channel interference (XCI) are the two main 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, and the spectrum blocks with the highest OSNR are selected first, and the first hit strategy is used for spectrum allocation.

[0103] In contrast, when a high-order modulation format is used in the C-band, the last hit strategy is used for spectrum allocation. The advantage of this strategy is that it can maintain the compactness of spectrum slot usage. When the service request is terminated and the spectrum is released, the released spectrum resources are relatively continuous. This makes it easier to meet the spectrum continuity requirements for subsequent service requests, thereby improving the availability of spectrum resources. At the same time, this strategy can also reduce the impact of the C-band on the L-band ISRS and improve the OSNR tolerance.

[0104] In step S8, the OSNR corresponding to the modulation format adopted by the current service request is compared with the 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 is successful.

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

[0106] In order to further illustrate the advantages of the present invention, it is described below in conjunction with specific experiments.

[0107] In order to achieve the goal of minimizing the time slot resources occupied by a group of business requests, the C+L band elastic optical network G(V,E,T,F) is first initialized, including the network topology information, the wavelength of the optical fiber link, and the two-dimensional time-frequency resources; secondly, a group of business requests are generated, including the source node, destination node, capacity requirement, and time slot requirement of the business request; finally, based on the weighted value of the optical fiber link, the spectrum is adaptively and intelligently allocated at the same time to obtain the optimization of spectrum resource occupation. The details are as follows:

[0108] First, Figure 2 (a) shows a network topology diagram of 4 nodes. The value on the fiber link represents the physical distance of the link in km. The basic bandwidth of each spectrum slot is set to 12.5 GHz, the number of frequency domain slots on each fiber link is 100, the number of time domain slots is 20, and the requested capacity range is 1-300 Gbps, using different modulation format levels.

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

[0110] third, Figure 2 The link weights calculated based on the two-dimensional time-frequency resource model are shown. An embodiment of performing route optimization. In this embodiment, Figure 2(a) shows that when a service request arrives from source node 1 to destination node 4, 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 obtained from formula (4) are shown in formulas (9), (10) and (11) respectively:

[0111]

[0112] like Figure 2 As shown, through the state matrices of the above three candidate paths, using formulas (1), (2) and (3), we can calculate the link weight of candidate path 1: 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, since the LW of path 3 p1 The value is the largest, so path 3 is selected for resource allocation. This selection feature not only takes into account the fragmentation of resource allocation in the path, but also takes into account controlling the transmission distance of the optical fiber link to reduce the impact of ISRS on signal transmission.

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

[0114] Fifth, the average modulation format level is calculated by formula (6): That is, BPSK and QPSK belong to low-order modulation formats, while 8-QAM and 16-QAM belong to high-order modulation formats. According to the total transmission distance of the selected path 3 of 300km, it is known that the modulation format in the service request resource allocation process is 16-QAM, and the modulation level m=4. At this time, spectrum allocation should be selected in the C band. The purpose of the present invention is to reduce the ISRS impact between the C band and the L band.

[0115] sixth, Figure 3The spectrum allocation method with adaptive signal-to-noise ratio is demonstrated. When the service request R(1,4,2,50) arrives and spectrum is allocated on the C band of path 3, the signal-to-noise ratio (OSNR) of the two spectrum blocks A and B available for allocation are calculated by formulas (7) and (8) to be 15dB and 13dB respectively. The larger the signal-to-noise ratio, the higher the transmission quality of the service request in the link. The value of the signal-to-noise ratio reflects the impact of the noise generated by the service request during the link transmission process on the initial signal, and also takes into account the amplified spontaneous emission noise and nonlinear noise, thereby optimizing the transmission quality of network resources.

[0116] Embodiment 2

[0117] like Figure 4 As shown, the present invention provides an intelligent spectrum allocation system for adaptive signal-to-noise ratio of a C+L optical network, which is used to implement the intelligent spectrum allocation method for adaptive signal-to-noise ratio of a C+L optical network of the first embodiment, and specifically includes:

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

[0119] A service request generation module, used to generate a set of service requests, the service request including a source node, a destination node, a required number of time slots and a capacity size of the service request;

[0120] A path selection module is used to calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, and select the path with the highest link weight as the working path for the service request;

[0121] A modulation format determination and spectrum slot calculation module, used to determine the corresponding modulation format according to the actual physical transmission distance of the selected working path, and calculate the number of spectrum slots 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 allocated to the C band for spectrum allocation; if it is a low-order modulation format, it is allocated to the L band for spectrum allocation;

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

[0124] An OSNR selection and spectrum allocation module, for calculating the OSNR of available spectrum blocks for each service request, and selecting the spectrum block with the highest OSNR for spectrum allocation, wherein OSNR represents optical signal-to-noise ratio;

[0125] The OSNR threshold comparison and request processing module is used to 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 immediately blocked, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing is successful.

[0126] In addition, the system also includes a performance evaluation module for calculating relevant evaluation indicators to evaluate network performance after completing spectrum allocation.

[0127] The intelligent spectrum allocation system for adaptive signal-to-noise ratio of a C+L optical network in this embodiment is used to implement the aforementioned intelligent spectrum allocation method for adaptive signal-to-noise ratio of a C+L optical network. Therefore, the specific implementation method of the intelligent spectrum allocation system for adaptive signal-to-noise ratio of a C+L optical network can be found in the embodiment section of the intelligent spectrum allocation method for adaptive signal-to-noise ratio of a C+L optical network in the preceding text. In order to avoid redundancy, it will not be repeated here.

[0128] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0129] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0130] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0131] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. An intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network, characterized in that: include: Step S1: Initializing the C+L band elastic optical network, the initialization includes determining a set of nodes in the network, a set of optical fiber links, a set of available spectrum slots in each optical fiber link, and a set of foreseeable time slots in the network; Step S2: generating a set of service requests, wherein the service request includes a source node, a destination node, a required number of time slots, and a capacity size of the service request; Step S3: Calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, and select the path with the highest link weight as the working path for the service request; Step S4: determining a corresponding modulation format according to an actual physical transmission distance of the selected working path, and calculating the number of spectrum slots required for the service request; Step S5: determining whether the modulation format is a high-order modulation format or a low-order modulation format; if it is a high-order modulation format, allocating it to the C band for spectrum allocation; if it is a low-order modulation format, allocating 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 the same spectrum slots are allocated on all optical fiber links of the selected optical channel. If yes, proceed to the next step. Otherwise, the user request processing fails. Step S7: For each service request, calculate the OSNR of the available spectrum blocks, and select the spectrum block with the highest OSNR for spectrum allocation, where OSNR represents 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 immediately blocked, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing is successful.

2. The intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network according to claim 1 is characterized in that: The method further includes: after completing the spectrum allocation, calculating relevant evaluation indicators to evaluate network performance.

3. The intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network according to claim 1 is characterized in that: In step S3, the method of calculating the link weight of each path according to 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: Step S31: using a K shortest path algorithm to calculate K paths from a source node to a destination node; Step S32: Calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, where the link weight It is expressed as: In the formula, represents the optical fiber transmission path p r The number of transmission nodes, l represents the link in the selected path, if l∈p r , then x l The value of is set to 1; Indicates the description of the optical fiber transmission path p r The time-frequency continuity of It describes the distance of the optical fiber transmission path; Step S33: Select the path with the highest link weight as the working path for the service request.

4. The intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network according to claim 3 is characterized in that: Said They are: Where |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 represents the link distance in the selected path; represents the optical fiber transmission path p r The total transmission distance; represents the optical fiber transmission path p r The spectrum occupancy is expressed as: in, Represents the matrix after the spectrum matrix is ​​inverted, that is, the spectrum state is 0 when it is idle and 1 when it is occupied.

5. The intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network according to claim 1 is characterized in that: In step S4, the method of determining the corresponding modulation format according to 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: determining a corresponding modulation format and modulation level according to an actual physical transmission distance of the selected working path; Step S42: Calculate the number of spectrum slots required for the service request according to the modulation level r : Where m represents the modulation level; Δ is the basic bandwidth of the spectrum slot; C r Indicates the capacity of the business request.

6. The intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network according to claim 1 is 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: 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 high-order modulation format; when M ave When M is less than the modulation level corresponding to the modulation format, the modulation format belongs to a low-order modulation format; ave The calculation formula is: In the formula, m[i] represents the modulation level corresponding to the modulation format requested by the service, and n represents the total number of modulation formats.

7. The intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network according to claim 1 is characterized in that: In step S7, the method for calculating the OSNR of the available spectrum block is: Where P represents the transmission power of service request r; represents the amplified spontaneous emission noise power of service request r; represents the nonlinear noise power of the service request r; represents the self-channel interference of service request r; represents the cross-channel interference of service request r; Represents the working path of service request r from source node s to destination node d.

8. The intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network according to claim 1 is characterized in that: The step S7 further includes: for the C band, using the last hit method to allocate the spectrum; for the L band, using the first hit method to allocate the spectrum.

9. An intelligent spectrum allocation system for adaptive signal-to-noise ratio of C+L optical network, characterized in that: The system is used to implement the intelligent spectrum allocation method for adaptive signal-to-noise ratio of C+L optical network according to any one of claims 1 to 8, specifically comprising: A network initialization module, used to initialize the C+L band elastic optical network, wherein the initialization includes determining a set of nodes in the network, a set of optical fiber links, a set of available spectrum slots in each optical fiber link, and a set of foreseeable time slots in the network; A service request generation module, used to generate a set of service requests, wherein the service request includes a source node, a destination node, a required number of time slots, and a capacity size of the service request; A path selection module is used to calculate the link weight of each path according to the transmission distance and spectrum occupancy status of the optical fiber link, and select the path with the highest link weight as the working path for the service request; A modulation format determination and spectrum slot calculation module, used to determine the corresponding modulation format according to the actual physical transmission distance of the selected working path, and calculate the number of spectrum slots required for the service request; A band selection module, used to determine whether the modulation format is a high-order modulation format or a low-order modulation format, and 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; The spectrum continuity and consistency check module is used to determine whether the spectrum slots allocated to each service request are continuous during the spectrum allocation process, and the same spectrum slots are allocated on all optical fiber links of the selected optical channel. If yes, the next step is executed, otherwise, the user request processing fails; An OSNR selection and spectrum allocation module, for calculating the OSNR of available spectrum blocks for each service request, and selecting the spectrum block with the highest OSNR for spectrum allocation, wherein OSNR represents optical signal-to-noise ratio; The OSNR threshold comparison and request processing module is used to 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 immediately blocked, that is, the user request processing fails. If the OSNR is not lower than the preset threshold, the user request processing is successful.

10. The intelligent spectrum allocation system for adaptive signal-to-noise ratio of C+L optical network according to claim 9, characterized in that: The system also includes a performance evaluation module, which is used to calculate relevant evaluation indicators after completing the spectrum allocation to evaluate the network performance.

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