A method for resource allocation in a hybrid space division multiplexing elastic optical network

Abstract

The application discloses a resource allocation method of a hybrid space division multiplexing elastic optical network and belongs to the technical field of optical communication. The application constructs a hybrid network model containing a multi-fiber bundle link and a multi-core optical fiber link, and designs a load and crosstalk aware heuristic algorithm. By means of modulation format step degradation, spectrum window plane construction to implicitly satisfy spectrum continuity constraints, load aware routing to balance network load, crosstalk aware core selection to suppress inter-core crosstalk, and optical signal-to-noise ratio verification to ensure transmission quality, joint optimization of routing, spectrum and spatial channels is realized. The application solves the problem that the prior art is only directed to a single type of space division multiplexing network and is difficult to adapt to a hybrid scene, effectively reduces network blocking rate under the premise of ensuring transmission quality, takes into account crosstalk suppression and spectrum efficiency, and has good engineering practicability.

Description

Technical Field

[0001] This invention relates to a resource allocation method for a hybrid spatial division multiplexing elastic optical network, belonging to the field of optical communication technology. Background Technology

[0002] With the continued rapid growth of global network traffic, optical networks are facing severe capacity bottleneck challenges. Traditional Elastic Optical Networks (EONs) are based on standard single-mode fiber (SSMF), and their transmission capacity is approaching the Shannon limit. Wavelength division multiplexing alone is insufficient to meet the ever-increasing bandwidth demands. Therefore, Space Division Multiplexing (SDM) technology has been introduced into Elastic Optical Networks, significantly increasing system capacity by transmitting multiple independent optical signals in parallel across a spatial dimension. Currently, the mainstream SDM solutions include two types: Multi-Fiber Bundle (MF) and Multi-Core Fiber (MCF). MF solutions are technologically mature and have no inter-core crosstalk, but their spatial efficiency is limited; MCF solutions offer high spatial integration and significant capacity advantages, but suffer from inter-core crosstalk (IC-XT) problems.

[0003] In practical network evolution, due to the large accumulation of existing MF infrastructure and the engineering cycle constraints of large-scale MCF deployment, MF and MCF will coexist in future optical networks for a long time, forming a hybrid space-division multiplexing elastic optical network (HybridSDM-EON). This hybrid architecture, while making full use of existing infrastructure, gradually introduces MCF to improve network capacity, representing a pragmatic choice that balances technological advancement and economic feasibility. However, due to the existence of two different transmission media (MF and MCF), how to efficiently allocate resources in this hybrid network has become a key focus of current research and engineering practice.

[0004] Currently, research on resource allocation in spatially divided multiplexing (SDM) flexible optical networks is relatively abundant, but most studies focus on single-type SDM network scenarios. In pure SDM networks, existing research mainly revolves around routing, fiber core, and spectrum allocation problems, including two main approaches: exact models based on integer linear programming and heuristic algorithms. Regarding inter-core crosstalk handling, existing strategies primarily include maximum effort avoidance strategies, fiber core priority strategies, and strict constraint strategies. The aforementioned research provides relatively mature solutions to the resource allocation and crosstalk management problems of multi-core optical fiber networks.

[0005] However, existing research on hybrid spatial multiplexing elastic optical networks where multi-fiber bundles and multi-core fiber links coexist is relatively limited. Most of the existing studies simplify the hybrid network approach, failing to fully consider the fundamental differences in capacity characteristics and physical impairments between the two types of links, and lacking a systematic method for resource allocation in hybrid networks.

[0006] Existing technologies have the following shortcomings in hybrid multi-fiber bundle / multi-core fiber network scenarios: First, most existing studies model single-type spatial multiplexing networks, failing to consider the gradual development trend of spatial multiplexing. Second, existing studies lack a unified physical impairment assessment framework applicable to hybrid networks, failing to incorporate amplifier spontaneous emission noise, nonlinear interference noise, and inter-core crosstalk noise into transmission quality constraints, thus lacking a reliable physical layer basis for resource allocation decisions. Furthermore, existing crosstalk-aware core selection strategies are mainly geared towards pure multi-core fiber network design, making it difficult to simultaneously achieve the dual objectives of inter-core crosstalk suppression and spectral fragmentation reduction in hybrid network scenarios. Summary of the Invention

[0007] The purpose of this invention is to provide a resource allocation method for a hybrid spatial division multiplexing elastic optical network. By combining a load-aware and crosstalk-aware resource allocation heuristic algorithm, it achieves joint optimization of routing, spectrum, and spatial channels. While ensuring transmission quality, it effectively reduces network blocking rate and balances crosstalk suppression and spectrum efficiency.

[0008] To achieve the above objectives / to solve the above technical problems, the present invention is implemented using the following technical solution.

[0009] On one hand, the present invention provides a resource allocation method for a hybrid spatial division multiplexing elastic optical network, characterized in that it includes:

[0010] In response to service requests, the modulation formats are traversed sequentially in descending order of spectral efficiency to generate and traverse the spectral window plane and determine the spectrum allocation.

[0011] The spectrum window plane generation and traversal process includes: calculating the number of frequency slots required for the service request based on the current modulation format;

[0012] Based on the required number of frequency slots, the spectrum resources of each link in the pre-constructed hybrid space-division multiplexing elastic optical network model are divided in a sliding window manner, and a set of spectrum window planes corresponding to different spectrum resource starting positions are constructed. Each spectrum window plane in the set is a virtual topology composed of links with at least one fiber core or fiber available at the starting position of the spectrum resource. Load and crosstalk sensing heuristic processing is performed based on the virtual topology of the current spectrum window plane.

[0013] The load and crosstalk awareness heuristic processing includes: calculating the cost function of each link based on the link length and the proportion of available resources on the link, and selecting the minimum cost path from the source node to the destination node for the service request;

[0014] After the minimum cost path is selected, differentiated spatial channel selection is performed according to the link type. Specifically, for multi-core fiber links, the fiber core with the least crosstalk risk is selected based on the spectral overlap rate of adjacent fiber cores; for multi-fiber bundle links, the fiber is selected based on the principle of minimizing spectral fragmentation.

[0015] Calculate the end-to-end integrated optical signal-to-noise ratio (OSNR) based on the selected minimum cost path and spatial channel combination, and perform OSNR verification to determine whether it meets the preset OSNR threshold of the current modulation format. If the OSNR verification is successful, the resource allocation is successful, and a complete resource allocation scheme is output. If the OSNR verification fails, return to traverse the next spectral window plane for the next round of load and crosstalk sensing heuristic processing until a complete resource allocation scheme is output or the service is determined to be blocked.

[0016] Furthermore, the method for determining service blockage specifically includes:

[0017] If the optical signal-to-noise ratio verification of the current spectral window fails, then traverse the next spectral window and repeat the next round of load and crosstalk sensing heuristic processing.

[0018] If the optical signal-to-noise ratio verification of all spectral window planes under the current modulation format fails, the modulation format is reduced, and the next round of spectral window plane generation and traversal processing is repeated.

[0019] If the generation and traversal of the spectral window plane for all modulation formats fails, the service is considered blocked.

[0020] Furthermore, the hybrid spatial division multiplexing elastic optical network model includes: a set of optical switching nodes V and a set of links E, wherein the set of links E is divided into a subset of multi-fiber bundle links. and multi-core fiber optic link subset ;

[0021] Each link in a multi-fiber bundle link contains One independent standard single-mode fiber;

[0022] Each link in a multi-core fiber optic link contains one fiber with... Multi-core optical fiber with one fiber core;

[0023] Each fiber core or fiber contains S frequency slots with a frequency slot granularity of 12.5 GHz.

[0024] Furthermore, the method for calculating the number of frequency slots includes:

[0025] ;

[0026] in: For the number of frequency slots, For the bit rate of the business request, The modulation efficiency of the current modulation format. For the frequency band width, The number of frequency slots corresponding to the protected bandwidth.

[0027] Furthermore, the method for determining the availability of the spectrum resources of each link, divided into spectrum windows using a sliding window approach, specifically includes:

[0028] ;

[0029] in, This indicates the occupancy status of the frequency slot s on the fiber core / fiber c on the link (i,j), where 0 indicates idle and 1 indicates occupied. The number of frequency slots required for the service request; This is a Boolean value; a value of 1 indicates that the current spectrum window is available, and a value of 0 indicates that it is not available. This is the k-th spectrum window object.

[0030] When the product of the occupancy status of all frequency slots under this spectrum window is 1, it means that the spectrum window is available.

[0031] Furthermore, the cost function of the link can be calculated as follows:

[0032] ;

[0033] in: For link In the spectrum window The cost function below;

[0034] For link The physical length;

[0035] and These are the lengths of the shortest and longest links in the network, respectively.

[0036] For link In the spectrum window The number of available fiber cores / fibers;

[0037] For link Total number of fiber cores / fibers;

[0038] These are the weighting coefficients.

[0039] Furthermore, the expression for calculating the spectral overlap rate of adjacent fiber cores is as follows:

[0040] ;

[0041] in, The overlap rate of the spectrum of adjacent fiber cores. For fiber core Adjacent fiber core sets, The number of frequency slots required for the business. For link fiber core Available frequency slots Occupied status, This is the number of the spectrum window;

[0042] Furthermore, the routing constraints for selecting the service request from the source node to the destination node specifically include:

[0043] ;

[0044] ;

[0045] ;

[0046] in: For nodes and nodes The link between them; For the source node A set of links for endpoints; For the destination node For the set of links at the endpoints, As the source node, For the destination node, For nodes A set of links for endpoints;

[0047] For business Does the path pass through a link? The binary variable is 1 if it passes through a certain condition, and 0 otherwise. For a set of business requests, Number the business request. For business requests Does the path pass through the node? The binary variable is 1 if it is passed through a binary variable, and 0 otherwise. Number the nodes. For a set of nodes in a hybrid spatial multiplexing elastic optical network;

[0048] The selection constraints for multi-core fiber links and multi-fiber bundle links specifically include:

[0049] ;

[0050] ;

[0051] in: A unified set of fiber core / fiber identification numbers. This is the fiber core / fiber number. A set of fiber optic numbers for multi-fiber bundle links; For business requests In the link Does it use fiber core / fiber? A binary variable is set to 1 if used, and 0 otherwise; A set of links in a network. For a subset of multi-fiber bundle links, A subset of multi-core fiber optic links;

[0052] The modulation format constraints specifically include:

[0053] ;

[0054] ;

[0055] in: This is the set of available modulation formats. For business requests Select modulation format? For binary variables, if the modulation format is selected... The value is 1 if it is 1, otherwise it is 0. Indicates a business request The actual number of frequency slots occupied, For business requests Using modulation format The number of frequency slots required at that time;

[0056] The maximum used slot index constraint of the hybrid spatial multiplexing elastic optical network model specifically includes:

[0057]

[0058] in: This is the index of the largest frequency slot used in the network. For business requests The assigned starting frequency slot index, For business requests The actual number of frequency slots occupied;

[0059] The optical signal-to-noise ratio constraint specifically includes:

[0060] ;

[0061] ;

[0062] in: For business requests The inverse value of the path OSNR, For link The inverse value of OSNR, Modulation format The reciprocal of the OSNR threshold, It is a positive number.

[0063] Furthermore, the constraints on spectrum allocation specifically include:

[0064] ;

[0065] ;

[0066] ;

[0067] ;

[0068] ;

[0069] ;

[0070] in: For business requests In the link fiber core / fiber Does it occupy a frequency slot? binary variables, For business requests In the link Does it use fiber core / fiber? A binary variable is set to 1 if used, and 0 otherwise. Number the business request. This is the fiber core / fiber number. Number the available frequency slots. For a set of business requests, A set of links in a network. A unified set of fiber core / fiber identification numbers. The total number of available frequency slots in each fiber / core For business requests The actual number of frequency slots occupied, It is a positive number. For business requests The assigned starting frequency slot index, For business requests The assigned starting frequency slot index, For business requests In the link Does it use fiber core / fiber? binary variables, For business requests The actual number of frequency slots occupied, This is an intermediate variable used for the non-overlapping spectral constraint.

[0071] Furthermore, crosstalk allocation constraints:

[0072] ;

[0073] ;

[0074] ;

[0075] ;

[0076] ;

[0077] ;

[0078] in: For link fiber core / fiber frequency gap A binary variable that is occupied by any business function is 1 if it is occupied, and 0 otherwise.

[0079] For business requests In the link fiber core / fiber Does it occupy a frequency slot? binary variables,

[0080] Number the business request. This is the fiber core / fiber number. Number the available frequency slots. For a set of business requests, A set of links in a network. A unified set of fiber core / fiber identification numbers. The total number of available frequency slots in each fiber / core For a subset of multi-core fiber optic links, For fiber core Adjacent fiber core sets, This refers to the set of fiber core numbers in a multi-core optical fiber.

[0081] For link fiber core / fiber frequency gap Binary variables that are occupied by arbitrary business operations

[0082] MCF link Adjacent fiber cores and In the frequency band The value is 1 if both variables are occupied simultaneously, and 0 otherwise.

[0083] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0084] This invention addresses the challenges of hybrid spatial division multiplexing (SDM) elastic optical networks where multi-fiber bundle links and multi-core fiber links coexist. It constructs a unified network model and resource allocation framework, incorporating both types of links into a joint optimization system of routing, spectrum, and spatial channels. This solves the problem that existing technologies, designed only for a single type of SDM network, are ill-suited for hybrid scenarios. In multi-core fiber links, the fiber with the lowest crosstalk risk is selected based on the spectral overlap rate of adjacent fibers. Crosstalk suppression is refined from a binary decision of "whether to occupy" to a continuous quantitative assessment of "overlap degree," allowing for moderate spectral overlap while ensuring transmission quality and avoiding overly conservative resource reservation. In multi-fiber bundle links, fiber selection is based on the principle of minimizing spectral fragmentation, effectively reducing spectral fragmentation. Thus, this invention achieves a balance between crosstalk suppression and spectral efficiency in the coordinated utilization of existing multi-fiber bundle infrastructure and newly added multi-core fiber capacity resources.

[0085] This invention implicitly satisfies spectral continuity constraints during spectral window plane construction and balances network traffic through load awareness during the routing phase, avoiding the risk of ignoring physical impairments by relying solely on resource availability allocation, thus significantly improving the reliability of optical path establishment. Furthermore, this invention designs a heuristic algorithm for load and crosstalk awareness, employing a cost function that considers both link physical length and available resource ratio during the routing phase. This guides services to prioritize links with ample resources, avoiding local resource overload. Combined with spectral window plane construction and minimum cost path selection, it balances service distribution globally. This invention's technical solution significantly reduces computational complexity while ensuring allocation quality, effectively lowering the overall network congestion rate and demonstrating good engineering practicality and scalability. Attached Figure Description

[0086] Figure 1 This is a schematic diagram of the process of the present invention;

[0087] Figure 2 A schematic diagram of constructing the spectrum window plane;

[0088] Figure 3 This is a diagram of the USNET network topology.

[0089] Figure 4 The graph shows the simulation results of the USNET network blocking rate.

[0090] Figure 5 The simulation results of the objective function values ​​for the USNET network are shown in the figure.

[0091] Figure 6 The graph shows the simulation results of the USNET network blocking rate. Detailed Implementation

[0092] It should be noted that:

[0093] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0094] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0095] Example 1

[0096] like Figures 1 to 2 The embodiment shown provides a resource allocation method for a hybrid spatial division multiplexing elastic optical network, specifically including:

[0097] Step 1: Initialize the network topology and modulation format set, specifically including:

[0098] like Figure 3 As shown, a USNET network was constructed as the test network topology. The ratio of MCF links to MF links in the network is approximately 1:1. The MCF links adopt a 7-core hexagonal close-packed structure, and the MF links contain 4 standard single-mode fibers. Each fiber core / fiber contains 320 frequency slots with a frequency slot granularity of 12.5 GHz. The maximum span distance of the optical amplifier is set to 80 km. It supports 6 modulation formats from BPSK (Binary Phase Shift Keying) to 64-QAM (64-Qorthogonal Amplitude Modulation). Each service is allocated one guard band frequency slot.

[0099] Step 2: Business Request Reaching the network specifically includes:

[0100] Generate a set of business requests R, each business request All include ,in and These represent the source node and destination node of the service, respectively. This represents the bandwidth requirements of the service. The bandwidth requirements of the service are uniformly distributed and randomly generated in the range of 100 to 800 Gbps. The arrival of the service follows a Poisson distribution, the duration follows a negative exponential distribution, and the network load varies from 700 Erlang to 1150 Erlang.

[0101] Step 3: Perform load and crosstalk-aware resource allocation. Following a heuristic algorithm, resource allocation is performed sequentially for each service request, specifically including:

[0102] Sub-step 3.1: Traverse the modulation format from high to low, specifically including:

[0103] The modulation format set is traversed in descending order of modulation efficiency, and the spectrum window plane is generated and traversed to determine the spectrum allocation.

[0104] Sub-step 3.2: Generation and traversal of the spectral window plane, specifically including:

[0105] Based on the modulation format selected for the current business, substitute... Calculate the number of frequency slots required for the service request under the current modulation format, generate the spectrum window for each link in the network topology, and substitute it into... Determine the availability of the spectrum window;

[0106] like Figure 2 As shown, a set of spectrum window planes for network topology is constructed based on the availability judgment results. If all fiber cores / fibers in a link are determined to be unavailable under the current spectrum window, the link will not be added to the spectrum window plane; if at least one fiber core / fiber in the link is available under the current spectrum window, it will be added to the spectrum window plane. The generated spectrum window planes are arranged in ascending order of their numbers, and the generated spectrum window plane set is traversed sequentially according to their numbers to perform load and crosstalk awareness heuristic processing.

[0107] Sub-step 3.3: Load and crosstalk-aware heuristic processing, specifically including:

[0108] according to Calculate the cost of each link on the spectrum window plane currently being traversed, and use Dijkstra's algorithm to find the route with the minimum cost value for the service request on the current spectrum window plane;

[0109] Sub-step 3.4: Determine if a route with the minimum cost value has been found. If found, proceed to sub-step 3.5; otherwise, jump to sub-step 3.8.

[0110] Sub-step 3.5: Crosstalk-sensing core / fiber selection, specifically including:

[0111] After determining the route for the service request, the algorithm selects a specific fiber or fiber core for each link along the path. If the link is a multi-core fiber, it utilizes... Calculate the spectral overlap rate of each fiber core and select the fiber core with the smallest spectral overlap rate between adjacent fiber cores; if the link is a multi-fiber bundle, select the fiber that produces the least spectral fragmentation.

[0112] Sub-step 3.6: Calculate the actual OSNR (Optical Signal-to-Noise Ratio) value of the route, specifically including:

[0113] Once this step is completed, a route and corresponding fiber core / fiber combination have been found for the service request. Then, the end-to-end optical signal-to-noise ratio of the current service request is calculated.

[0114] Sub-step 3.7: Determine the end-to-end optical signal-to-noise ratio (OSNR) value of the current service request. If it is greater than the preset OSNR value (OSNR threshold) of the current modulation format, proceed to step 4; if it is less than the preset OSNR value (OSNR threshold) of the current modulation format, proceed to sub-step 3.8.

[0115] Sub-step 3.8: Determine whether the current spectral window plane is the last spectral window plane. If yes, proceed to sub-step 3.9; otherwise, select the next spectral window plane and proceed to sub-step 3.3.

[0116] Sub-step 3.9: Determine if the current modulation format is the last modulation format. If yes, determine if the service is blocked. If not, perform a modulation format downgrade operation and jump to sub-step 3.2.

[0117] Step 4: Service request allocation successful, optical path successfully established, network status updated, proceed to the next service request allocation, and go to Step 5.

[0118] Step 5: Repeat steps 3-4 until all business requests have been processed, and then calculate the blocking rate and average crosstalk level.

[0119] In this embodiment, the service request selects routing constraints from the source node to the destination node, specifically including:

[0120] ;

[0121] ;

[0122] ;

[0123] in: For nodes and nodes The link between them; For the source node A set of links for endpoints; For the destination node For the set of links at the endpoints, As the source node, For the destination node, For nodes For the set of links at the endpoints,

[0124] For business Does the path pass through a link? The binary variable is 1 if it passes through a certain condition, and 0 otherwise. For a set of business requests, Number the business request. For business requests Does the path pass through the node? The binary variable is 1 if it is passed through a binary variable, and 0 otherwise. Number the nodes. For a set of nodes in a hybrid spatial multiplexing elastic optical network;

[0125] The selection constraints for multi-core fiber links and multi-fiber bundle links specifically include:

[0126] ;

[0127] ;

[0128] in: A unified set of fiber core / fiber identification numbers. This is the fiber core / fiber number. A set of fiber optic numbers for multi-fiber bundle links; For business requests In the link Does it use fiber core / fiber? A binary variable is set to 1 if used, and 0 otherwise; A set of links in a network. For a subset of multi-fiber bundle links, A subset of multi-core fiber optic links;

[0129] The modulation format constraints specifically include:

[0130] ;

[0131] ;

[0132] in: This is the set of available modulation formats. For business requests Select modulation format? For binary variables, if the modulation format is selected... The value is 1 if it is 1, otherwise it is 0. Indicates a business request The actual number of frequency slots occupied, For business requests Using modulation format The number of frequency slots required at that time;

[0133] The maximum used slot index constraint of the hybrid spatial multiplexing elastic optical network model specifically includes:

[0134] ;

[0135] in: This is the index of the largest frequency slot used in the network. For business requests The assigned starting frequency slot index, For business requests The actual number of frequency slots occupied;

[0136] The optical signal-to-noise ratio constraint specifically includes:

[0137] ;

[0138] ;

[0139] in: For business requests The inverse value of the path OSNR, For link The inverse value of OSNR, Modulation format The reciprocal of the OSNR threshold, It is a positive number.

[0140] The constraints on spectrum allocation specifically include:

[0141] ;

[0142] ;

[0143] ;

[0144] ;

[0145] ;

[0146] ;

[0147] in: For business requests In the link fiber core / fiber Does it occupy a frequency slot? binary variables, For business requests In the link Does it use fiber core / fiber? A binary variable is set to 1 if used, and 0 otherwise. Number the business request. This is the fiber core / fiber number. Number the available frequency slots. For a set of business requests, A set of links in a network. A unified set of fiber core / fiber identification numbers. The total number of available frequency slots in each fiber / core For business requests The actual number of frequency slots occupied, It is a positive number. For business requests The assigned starting frequency slot index, For business requests The assigned starting frequency slot index, For business requests In the link Does it use fiber core / fiber? binary variables, For business requests The actual number of frequency slots occupied, As an intermediate variable used for spectrum non-overlap constraints, if the service request and Both use links fiber core / fiber And business requests The spectrum in If it is before, it is 1; otherwise, it is 0.

[0148] Crosstalk allocation constraints:

[0149] ;

[0150] ;

[0151] ;

[0152] ;

[0153] ;

[0154] ;

[0155] in: For link fiber core / fiber frequency gap A binary variable that is occupied by any business function is 1 if it is occupied, and 0 otherwise.

[0156] For business requests In the link fiber core / fiber Does it occupy a frequency slot? binary variables,

[0157] Number the business request. This is the fiber core / fiber number. Number the available frequency slots. For a set of business requests, A set of links in a network. A unified set of fiber core / fiber identification numbers. The total number of available frequency slots in each fiber / core For a subset of multi-core fiber optic links, For fiber core Adjacent fiber core sets, This refers to the set of fiber core numbers in a multi-core optical fiber.

[0158] For link fiber core / fiber frequency gap Binary variables that are occupied by arbitrary business operations

[0159] MCF link Adjacent fiber cores and In the frequency band The value is 1 if both variables are occupied simultaneously, and 0 otherwise.

[0160] like Figure 4As shown, the Crosstalk and LoadAware Resource Allocation (CLARA) algorithm proposed in this invention is evaluated in the USNET network. For comparison, this invention also introduces two benchmark algorithms: XT-Aware (XTA): employing a traditional shortest path routing strategy while retaining a crosstalk-aware fiber core selection strategy, this algorithm is used to verify the effectiveness of the load-aware routing strategy; and Path-Distance Aware (PDA): combining a shortest path routing strategy with a random fiber core selection strategy, considering only the impact of path distance on transmission quality, representing a traditional resource allocation method. Figure 4 The horizontal axis represents network load (in Erlang), and the vertical axis represents bandwidth blocking probability (BBP). Simulation results show that the CLARA algorithm achieves the lowest bandwidth blocking probability under different network load conditions, demonstrating stable and significant performance advantages. As network load increases, the bandwidth blocking probability of all three algorithms shows an upward trend, but the increase in CLARA is significantly lower than that of XTA and PDA, especially in the low-to-medium load range (0~80 Erlang), where the performance difference is more pronounced.

[0161] like Figure 5 As shown, this invention further compares the weighted sum (objective function value) of the maximum number of occupied frequency slots and the number of overlapping spectra of adjacent fiber cores under different allocation strategies. Simulation results show that the crosstalk and load sensing algorithm proposed in this invention can achieve the minimum objective value compared with the two comparison algorithms mentioned above, that is, achieve the best performance. This verifies its superiority in jointly optimizing spectrum utilization and crosstalk sensing.

[0162] like Figure 6 As shown in the figure, the present invention also compares the performance of different routing strategies and fiber core continuity constraints. The simulation results in the figure show that the overall performance of the algorithm proposed in this invention is significantly better than the traditional fixed routing algorithm (KSP), and also better than the allocation method that does not support the No-Core Switch constraint.

[0163] This invention employs a multi-level cyclic processing flow involving modulation format degradation, spectral window plane traversal, and optical signal-to-noise ratio verification. This implicitly satisfies spectral continuity constraints during spectral window plane construction and balances network traffic through load awareness during the routing phase. This avoids the risk of ignoring physical damage by relying solely on resource availability allocation, thus significantly improving the reliability of optical path establishment.

[0164] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A resource allocation method for a hybrid spatial division multiplexing elastic optical network, characterized in that, include: In response to service requests, the modulation formats are traversed sequentially in descending order of spectral efficiency to generate and traverse the spectral window plane and determine the spectrum allocation. The spectrum window plane generation and traversal process includes: calculating the number of frequency slots required for the service request based on the current modulation format; Based on the required number of frequency slots, the spectrum resources of each link in the pre-constructed hybrid space-division multiplexing elastic optical network model are divided in a sliding window manner, and a set of spectrum window planes corresponding to different spectrum resource starting positions are constructed. Each spectrum window plane in the set is a virtual topology composed of links with at least one fiber core or fiber available at the starting position of the spectrum resource. Load and crosstalk sensing heuristic processing is performed based on the virtual topology of the current spectrum window plane. The load and crosstalk awareness heuristic processing includes: calculating the cost function of each link based on the link length and the proportion of available resources on the link, and selecting the minimum cost path from the source node to the destination node for the service request; After the minimum cost path is selected, differentiated spatial channel selection is performed according to the link type. Specifically, for multi-core fiber links, the fiber core with the least crosstalk risk is selected based on the spectral overlap rate of adjacent fiber cores; for multi-fiber bundle links, the fiber is selected based on the principle of minimizing spectral fragmentation. Calculate the end-to-end integrated optical signal-to-noise ratio (OSNR) based on the selected minimum cost path and spatial channel combination, and perform OSNR verification to determine whether it meets the preset OSNR threshold of the current modulation format. If the OSNR verification is successful, the resource allocation is successful, and a complete resource allocation scheme is output. If the OSNR verification fails, return to traverse the next spectral window plane for the next round of load and crosstalk sensing heuristic processing until a complete resource allocation scheme is output or the service is determined to be blocked.

2. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, The method for determining service blockage specifically includes: If the optical signal-to-noise ratio verification of the current spectral window fails, then traverse the next spectral window and repeat the next round of load and crosstalk sensing heuristic processing. If the optical signal-to-noise ratio verification of all spectral window planes under the current modulation format fails, the modulation format is reduced, and the next round of spectral window plane generation and traversal processing is repeated. If the generation and traversal of the spectral window plane for all modulation formats fails, the service is considered blocked.

3. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, The hybrid space-division multiplexing elastic optical network model includes: a set of optical switching nodes V and a set of links E, wherein the set of links E is divided into a subset of multi-fiber bundle links. and multi-core fiber optic link subset ; Each link in a multi-fiber bundle link contains One independent standard single-mode fiber; Each link in a multi-core fiber optic link contains one fiber with... Multi-core optical fiber with one fiber core.

4. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, The method for calculating the number of frequency slots includes: ； in: For the number of frequency slots, For the bit rate of the business request, The modulation efficiency of the current modulation format. For the frequency band width, The number of frequency slots corresponding to the protected bandwidth.

5. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, The specific methods for determining the availability of spectrum resources for each link, divided into spectrum windows using a sliding window approach, include: ； in, This indicates the occupancy status of the frequency slot s on fiber core / fiber c in link (i,j). The number of frequency slots required for the service request; It is a Boolean value. For the k-th spectral window object, This is the number of the spectrum window.

6. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, The cost function of the link is calculated as follows: ； in: For link In the spectrum window The cost function below; For link The physical length; and These are the lengths of the shortest and longest links in the network, respectively. For link In the spectrum window The number of available fiber cores / fibers; For link Total number of fiber cores / fibers; These are the weighting coefficients.

7. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, The formula for calculating the spectral overlap rate of adjacent fiber cores is as follows: ； in, The overlap rate of the spectrum of adjacent fiber cores. For fiber core Adjacent fiber core sets, The number of frequency slots required for the service request. For link fiber core Available frequency slots Occupied status, This is the number of the spectrum window.

8. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, The service request selects routing constraints from the source node to the destination node, specifically including: ； ； ； in: For nodes and nodes The link between them; For the source node A set of links for endpoints; For the destination node For the set of links at the endpoints, As the source node, The destination node; For business Does the path pass through a link? binary variables, For a set of business requests, Number the business request. For business requests Does the path pass through the node? binary variables, Number the nodes. For nodes For the set of links at the endpoints, For a set of nodes in a hybrid spatial multiplexing elastic optical network; The selection constraints for multi-core fiber links and multi-fiber bundle links specifically include: ； ； in: A unified set of fiber core / fiber identification numbers. This is the fiber core / fiber number. This is a set of fiber IDs for multi-fiber bundle links. For business requests In the link Does it use fiber core / fiber? binary variables, A set of links in a network. For a subset of multi-fiber bundle links, A subset of multi-core fiber optic links; The modulation format constraints specifically include: ； ； in: This is the set of available modulation formats. For business requests Select modulation format? binary variables, Indicates a business request The actual number of frequency slots occupied, For business requests Using modulation format The number of frequency slots required at that time; The maximum used slot index constraint of the hybrid spatial multiplexing elastic optical network model specifically includes: ； in: This is the index of the largest frequency slot used in the network. For business requests The assigned starting frequency slot index, For business requests The actual number of frequency slots occupied; The optical signal-to-noise ratio constraint specifically includes: ； ； in: For business requests The inverse value of the path OSNR, For link The inverse value of OSNR, Modulation format The reciprocal of the OSNR threshold, It is a positive number.

9. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, The constraints on spectrum allocation specifically include: ； ； ； ； ； ； in: For business requests In the link fiber core / fiber Does it occupy a frequency slot? binary variables, For business requests In the link Does it use fiber core / fiber? binary variables, Number the business request. This is the fiber core / fiber number. Number the available frequency slots. For a set of business requests, A set of links in a network. A unified set of fiber core / fiber identification numbers. The total number of available frequency slots in each fiber / core For business requests The actual number of frequency slots occupied, It is a positive number. For business requests The assigned starting frequency slot index, For business requests The assigned starting frequency slot index, For business requests In the link Does it use fiber core / fiber? binary variables, For business requests The actual number of frequency slots occupied As an intermediate variable used for spectrum non-overlap constraints, if the service request and Both use links fiber core / fiber And business requests The spectrum in If it is before, it is 1; otherwise, it is 0.

10. The resource allocation method for a hybrid spatial division multiplexing elastic optical network according to claim 1, characterized in that, Crosstalk allocation constraints: ； ； ； ； ； ； in: For link fiber core / fiber frequency gap A binary variable that can be used by any business function; For business requests In the link fiber core / fiber Does it occupy a frequency slot? binary variables, Number the business request. This is the fiber core / fiber number. Number the available frequency slots. For a set of business requests, A set of links in a network. A unified set of fiber core / fiber identification numbers. The total number of available frequency slots in each fiber / core For a subset of multi-core fiber optic links, For fiber core Adjacent fiber core sets, This refers to the set of fiber core numbers in a multi-core optical fiber. For link fiber core / fiber frequency gap Binary variables that are occupied by arbitrary business operations MCF link Adjacent fiber cores and In the frequency band A binary variable that is occupied at the same time.

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