C + L EON resource optimization method and system based on service priority and signal-to-noise ratio

Abstract

The invention relates to the technical field of optical networks, and discloses a C + LEON resource optimization method and system based on a service priority and a signal-to-noise ratio, and the method comprises the steps: calculating the number of frequency spectrum slots required by a current service request and a working path, judging whether to reserve the service request in real time or in advance according to the maximum tolerable delay time, and if yes, determining whether to reserve the service request in advance; calculating the priority of the service request reserved in advance for resource allocation; whether a high-order modulation format or a low-order modulation format is applied to the current service request is judged according to the average level of all the modulation formats, if the high-order modulation format is applied, a final hit method is used for spectrum allocation in a C wave band, and if the low-order modulation format is applied, a first hit method is used for spectrum allocation in an L wave band; and calculating the optical signal-to-noise ratio of the currently available spectrum resources, and when the optical signal-to-noise ratio is higher than a preset threshold value, selecting the spectrum resource corresponding to the highest optical signal-to-noise ratio to establish service connection. According to the invention, when different types of service requests are processed, the utilization rate of network resources is improved, the delay and blocking rate is reduced, and the service quality is improved.

Description

Technical Field

[0001] This invention relates to the field of optical network technology, and in particular to a C+L EON resource optimization method and system based on service priority and signal-to-noise ratio. Background Technology

[0002] In Elastic Optical Networks (EONs), bandwidth is typically provided through spectrum resources, making the efficient utilization and rational allocation of these resources crucial. C+L band Elastic Optical Networks (EONs) are optical communication technologies that utilize both the C-band (typically referring to the 1550nm to 1650nm wavelength range) and the L-band (typically referring to the 1650nm to 1700nm wavelength range) to achieve high-speed, flexible data transmission networks. With the increasing demand for bandwidth and the rise of various emerging applications, the resource allocation problem in C+L band EONs has become particularly important. In EON applications, especially in the C+L band, the limited network spectrum resources and constantly changing service requirements make effectively utilizing resources while meeting diverse service needs a technical challenge. Especially when facing diverse and large-scale service requests, existing resource allocation strategies suffer from inefficiency and congestion, failing to cope with ever-increasing traffic demands and complex service scenarios. Therefore, how to effectively allocate spectrum resources to meet both the low latency requirements of immediate reserved service requests and the flexibility of advance reserved service requests has become an urgent problem to be solved.

[0003] In C+L band elastic optical networks, service requests can be categorized into immediate reserved service requests and advance reserved service requests based on service timeliness requirements. Immediate reserved service requests require immediate resource allocation and connection establishment upon arrival, demanding a very short network response time and high real-time performance and reliability. Advance reserved service requests, on the other hand, allow for a certain delay, providing a time buffer to moderately postpone resource allocation and complete spectrum resource allocation within a set timeframe. These two types of requests differ significantly in resource requirements, time constraints, and tolerance levels. Balancing the priorities of these two types of requests to ensure that all service requests are satisfied within a reasonable timeframe is a key issue in resource allocation strategies. Improper resource allocation can lead to a significant degrade in network performance, unprocessed requests, or even service interruptions, severely impacting the user experience.

[0004] Furthermore, with the increasing number of service requests and the strain on network resources, balancing the priorities of different service requests and dynamically adjusting resource allocation according to their specific needs has become increasingly important. Because different types of service requests have different timeliness requirements and latency tolerances, traditional resource allocation methods primarily rely on request arrival times for priority ranking. This single-dimensional evaluation method fails to fully consider multiple factors such as service capacity requirements, service arrival times, service duration, and maximum tolerable latency. Due to the lack of comprehensive evaluation, unreasonable resource allocation may occur, causing some real-time-critical services to be unable to obtain the necessary resources in a timely manner, leading to network congestion and performance degradation. This results in low network resource utilization and reduced transmission efficiency, failing to meet the ever-increasing service demands. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a C+L EON resource optimization method and system based on service priority and signal-to-noise ratio, which can improve network resource utilization efficiency, reduce latency and blocking rate, and improve service quality while processing different types of service requests.

[0006] To address the aforementioned technical problems, this invention provides a C+L EON resource optimization method based on service priority and signal-to-noise ratio, comprising:

[0007] Initialize the C+L band elastic optical network and set up optical amplifiers on the optical fiber links of the C+L band elastic optical network;

[0008] Obtain the current business request, and calculate the required number of spectrum slots and candidate working paths for the current business request;

[0009] Based on the maximum tolerable latency of the service request, determine whether the current service request is an immediate reservation service request or an advance reservation service request. Combine the required number of spectrum slots, the duration of the service request, the arrival time of the service request, and the maximum tolerable latency of the service request to calculate the priority of the advance reservation service request for resource allocation.

[0010] The modulation format of the current service request is selected based on the transmission distance. The average level of all modulation formats is calculated. Based on the average level, it is determined whether the current service request should use a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, the last hit method is used to allocate the spectrum in the C-band. If it is a low-order modulation format, the first hit method is used to allocate the spectrum in the L-band.

[0011] If the current service request is an immediate reserved service request, determine whether there are enough available spectrum resources at the service arrival time. If not, block. If the current service request is an advance reserved service request within the maximum tolerable delay time, continuously reallocate service requests until there are enough available spectrum resources to carry the current service request.

[0012] The optical signal-to-noise ratio (OSR) of the currently available spectrum resources is calculated by combining the amplifier spontaneous emission noise power and nonlinear noise power of the current service request. When the OSR is higher than a preset threshold, the spectrum resource corresponding to the highest OSR is selected to establish a service connection; otherwise, the connection is blocked.

[0013] Furthermore, the method for calculating the required number of spectral gaps is as follows:

[0014]

[0015] Among them, slots r For the required number of spectral gaps, C r This represents the capacity of the current service request, Δ is the base bandwidth of the spectrum slot, GB represents the spectrum slot bandwidth for protecting the service request, and m is the modulation level determined based on the actual physical transmission distance of the current service request.

[0016] Furthermore, the duration of the service request is set to be an integer multiple of the unit time slot, and the actual start time for spectrum allocation of the service request is after the initial arrival time to schedule resource space. The instant reservation service request and the advance reservation service request are respectively:

[0017]

[0018] Where R represents the set of business requests, and the current business request is represented by r(s,d,t). a ,td max H t f) represents, where s represents the source node, d represents the destination node, and t represents the destination node. a It is the arrival time of the business request, td max H represents the maximum tolerable latency for a business request. t The duration of the service request is represented by f, and the required spectrum slot capacity is represented by f. The service request r represents the service request from source node s to destination node d, where r(s,d,t) is the service request from source node s to destination node d. a ,td max H t f)∈R; IR represents immediate reserved service request, AR represents advance reserved service request, t s This indicates the actual start time of the service request for spectrum allocation.

[0019] Furthermore, the priority of the pre-reserved service requests for resource allocation is specifically as follows:

[0020] SP(C r ,t a H t ,td max ) = RS(C r H t )×TU(t a ,td max ),

[0021] Among them, SP(C r ,t a H t ,td max RS(C) indicates the priority of reserving service requests for resource allocation in advance. r H t ) represents the estimated resource allocation requirement for pre-reserved service requests, TU(t) a ,td max This indicates the urgency of reserving business requests in advance for resource allocation.

[0022] Furthermore, the RS(C) r H t The calculation method for ) is as follows:

[0023] RS(C r H t ) = slots r ×H t ,

[0024] Among them, slots r H is the number of spectral gaps required. t Indicates the duration of the business request.

[0025] Furthermore, the TU(t) a ,td max The calculation method for ) is as follows:

[0026]

[0027] Among them, t a It is the arrival time of the business request, td max This represents the maximum tolerable delay time for a business request, where a1 and a2 are preset coefficients.

[0028] Furthermore, the calculation of the average level of all modulation formats, and the determination of whether the current service request applies a high-order modulation format or a low-order modulation format based on the average level, specifically involves:

[0029] The average level for all modulation formats is calculated as follows:

[0030]

[0031] Among them, M ave The average level is represented by m[i], where m[i] represents the modulation level corresponding to the i-th modulation format, and n represents the total number of modulation formats.

[0032] If the modulation level corresponding to the modulation format requested by the current service is greater than the average level, then the higher-order modulation format shall be applied; otherwise, the lower-order modulation format shall be applied.

[0033] Furthermore, the method for calculating the optical signal-to-noise ratio is as follows:

[0034]

[0035] Among them, OSNR r Let P be the optical signal-to-noise ratio of the currently available spectrum resources corresponding to the current service request, and let P be the transmit power of the current service request. This indicates the amplifier's spontaneously radiated noise power in the current service request. This represents the nonlinear noise power of the current service request.

[0036] Furthermore, the method for calculating the nonlinear noise power of the current service request is as follows:

[0037]

[0038] in, This represents the working path of the current business request from the source node s to the destination node d. For the current service request, there is interference on the fiber optic link in segment l. Inter-channel interference for the current service request on the l-th fiber optic link.

[0039] This invention also provides a C+L EON resource optimization system based on service priority and signal-to-noise ratio, comprising:

[0040] The elastic optical network initialization module is used to initialize the C+L band elastic optical network and set up optical amplifiers on the optical fiber links of the C+L band elastic optical network.

[0041] The business request acquisition module is used to acquire the current business request and calculate the required number of spectrum slots and candidate working paths for the current business request.

[0042] The service request priority calculation module is used to determine whether the current service request is an immediate reservation service request or a pre-reserved service request based on the maximum tolerable latency time of the service request. If it is a pre-reserved service request, the priority of the pre-reserved service request for resource allocation is calculated based on the required number of spectrum slots.

[0043] The spectrum allocation band selection module is used to select the modulation format of the current service request based on the transmission distance, calculate the average level of all modulation formats, and determine whether the current service request should apply a high-order modulation format or a low-order modulation format based on the average level. If it is a high-order modulation format, the last hit method is used to allocate spectrum in the C band; if it is a low-order modulation format, the first hit method is used to allocate spectrum in the L band.

[0044] The spectrum allocation module is used to determine whether there are enough available spectrum resources at the time of service arrival if the current service request is an immediate reserved service request. If not, it will block. If the current service request is an advance reserved service request within the maximum tolerable delay time, it will continuously reallocate the service request until there are enough available spectrum resources to carry the current service request.

[0045] The service connection establishment module is used to calculate the optical signal-to-noise ratio (OSR) of the currently available spectrum resources by combining the amplifier spontaneous emission noise power and nonlinear noise power of the current service request. When the OSR is higher than a preset threshold, the spectrum resource corresponding to the highest OSR is selected to establish a service connection; otherwise, the connection is blocked.

[0046] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0047] This invention, when processing different types of reserved service requests, categorizes them into immediate reserved service requests and advance reserved service requests, calculates the priority of advance reserved service requests for resource allocation, and achieves a balance in the priority of different types of service requests. This ensures the timely processing of high-priority service requests, effectively reducing network congestion rate while improving system transmission quality. Furthermore, by combining optical signal-to-noise ratio (SNR) to select different bands and using different methods for spectrum allocation, the network can respond more flexibly and efficiently to different types and priorities of service requests, maximizing the utilization of network resources. Attached Figure Description

[0048] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0049] Figure 1 This is a flowchart of a preferred embodiment of the present invention.

[0050] Figure 2 This is a flowchart illustrating the steps of a method in a preferred embodiment of the present invention.

[0051] Figure 3 This is an example diagram of the network topology constructed in a preferred embodiment of the present invention.

[0052] Figure 4 This is an example diagram illustrating the priority evaluation of resource allocation for three groups of reserved service requests in a preferred embodiment of the present invention. Detailed Implementation

[0053] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0054] Reference Figure 1 , Figure 2 As shown, this invention discloses a C+L EON resource optimization method based on service priority and signal-to-noise ratio, comprising the following steps:

[0055] S1: Initialize the C+L band elastic optical network and set up optical amplifiers on the optical fiber links of the C+L band elastic optical network.

[0056] In this embodiment, G(V,E,T,F) represents the C+L band elastic optical network, where V represents the set of nodes in the network, E represents a set of fiber optic links in the network, and F = {f1,…,f...} i ,…,f |F|} represents the number of available spectrum slots in each fiber optic link, f i Let |F| represent the number of available spectrum slots in the i-th fiber optic link, and |F| represent the number of fiber optic links. T = {t1, ...,t} i ,…,t |T|} represents the set of foreseeable timeslots in the network, t i Let |T| represent the i-th foreseeable time slot, and |T| represent the total number of foreseeable time slots.

[0057] Furthermore, typical fiber attenuation near the 1550nm spectrum is approximately 0.2dB / km, which limits the achievable transmission distance of the fiber. Therefore, to compensate for these losses, optical amplifiers must be used in resilient optical network transmission systems. In this embodiment, erbium-doped fiber amplifiers (EDFAs) are placed at regular intervals to effectively compensate for fiber attenuation, taking into account the actual situation.

[0058] like Figure 3 The image shown is an example of the network topology constructed in this embodiment. Figure 3 The unit of distance between the optical fiber links is km. This network topology has 14 nodes and 21 bidirectional links. The values ​​on the optical fiber links represent the physical distance of the links, in km. The basic bandwidth of each spectrum slot is set at 12.5 GHz, and the capacity of the optical fiber links is 100 frequencies, of which 30 frequency slots are occupied by the L-band and 70 frequency slots are occupied by the C-band.

[0059] S2: Obtain the current service request, calculate the required number of spectrum slots and candidate working paths for the current service request.

[0060] The current business request uses r(s,d,t) a ,td max H t f) represents, where s represents the source node, d represents the destination node, and t represents the destination node. a It is the arrival time of the business request, td max H represents the maximum tolerable latency for a business request. t H represents the duration of the service request, f represents the spectrum slot capacity requirement of the service request, and r represents the service request from source node s to destination node d, based on the duration H of the service request. t The time slots required for a business request can be calculated. Let R represent the set of business requests, r(s,d,t) a ,td max H t ,f)∈R.

[0061] In view of the different processing times for spectrum resources for immediate and advance reserved service requests, this invention defines the concept of tolerable delay time, which aims to solve the resource allocation problem for different reserved service requests and reflects the urgency of service requests in C+L band elastic optical networks.

[0062] When a service request r arrives at the elastic optical network, the bandwidth capacity of the current service request's spectrum slots can be expressed as m*ΔGb / s. The method for calculating the required number of spectrum slots is as follows:

[0063]

[0064] Among them, slots r For the required number of spectral gaps, C r The value represents the capacity of the current service request. Δ is the base bandwidth of the spectrum slot. In this embodiment, Δ = 12.5 Gb / s. GB represents the spectrum slot bandwidth for protecting the service request. m is the modulation level determined based on the actual physical transmission distance of the current service request. The modulation level, transmission distance, and OSNR threshold corresponding to the modulation format are shown in Table 1.

[0065] Table 1. Correspondence between modulation format, modulation level, transmission distance, and OSNR threshold.

[0066] Modulation format Modulation level Transmission distance range (km) Optical signal-to-noise ratio threshold (dB) BPSK 1 >4000 9 QPSK 2 (2000,4000] 12 8-QAM 3 (1000,2000] 16 16-QAM 4 <＝1000 18.6

[0067] The K-shortest path algorithm is used to calculate candidate working paths for the current service request. As the number of spectrum slots occupied by the fiber optic link increases and the transmission distance of the fiber optic link increases, the impact of inter-band stimulated Raman scattering (ISRS) on the fiber optic link also becomes increasingly significant. In this embodiment, the K-shortest path algorithm is first used to find K paths between node pairs. These K paths are then stored in a routing table sorted by weights calculated based on the product of spectrum occupancy and transmission distance. Fiber optic links with relatively low spectrum resource consumption and shorter transmission distances are preferentially selected as transmission routes.

[0068] In this embodiment, the maximum predictable number of time slots in the elastic optical network is 20. The bandwidth requirements of service requests are uniformly distributed between 12.5Gb / s and 200Gb / s, the guard bandwidth GB is set to 1 spectrum slot, and the number of candidate paths K is 3. The maximum tolerable latency is uniformly generated within the range of [0, 5].

[0069] In this embodiment, three sets of service requests are generated, namely:

[0070] Group 1: The reserved service request R1 has a capacity requirement of 150Gb / s, and the arrival time is t. a The first time unit, duration H t Given 4 units of time, its maximum tolerable delay time td max It is 0.

[0071] Group 2: The reserved service request R2 has a capacity requirement of 200Gb / s, and the arrival time is t. a The second time unit, duration H t Given 4 units of time, its maximum tolerable delay time td max It is 2 units of time.

[0072] Group 3: The reserved service request R3 has a capacity requirement of 100Gb / s, with an arrival time t. a The first time unit, duration H t The maximum tolerable delay time is 2 and 3 units of time, respectively.

[0073] S3: Determine whether the current service request is an immediate reservation or a pre-reserved service request based on the maximum tolerable latency of the service request. If it is a pre-reserved service request, calculate the priority of the pre-reserved service request for resource allocation by combining the required number of spectrum slots, the duration of the service request, the arrival time of the service request, and the maximum tolerable latency of the service request.

[0074] To simultaneously handle both immediate and advance reservation service requests in the network, the duration of each service request is set to an integer multiple of a unit time slot, and the actual start time t for spectrum allocation of the service request is determined. s Only at the initial arrival time t a Then, resource space is allocated. To differentiate between immediate reserved service requests and pre-reserved service requests, a maximum tolerable latency time td is introduced. max The concept, when td max When td is zero, the service request is an immediate reserved service request, which must be processed immediately upon arrival at the network. max When the value is greater than zero, the service request is a pre-reserved service request, which allows spectrum allocation within a certain initial delay period. That is, the immediate reserved service request and the pre-reserved service request are respectively:

[0075]

[0076] Where R represents the set of business requests, and the current business request is represented by r(s,d,t). a ,td max H t f) represents, where s represents the source node, d represents the destination node, and t represents the destination node. a It is the arrival time of the business request, td max H represents the maximum tolerable latency for a business request. t The duration of the service request is represented by f, and the required spectrum slot capacity is represented by f. The service request r represents the service request from source node s to destination node d, where r(s,d,t) is the service request from source node s to destination node d. a ,td max H t f)∈R; IR represents immediate reserved service request, AR represents advance reserved service request, t s This indicates the actual start time of the service request for spectrum allocation.

[0077] In the routing, modulation, and spectrum allocation problems of elastic optical networks, the spectrum resources required by service requests depend not only on the frequency domain bandwidth requirements of the service requests, which adaptively adjust the modulation format according to the actual physical distance, but also on the time domain bandwidth requirements due to the duration. This embodiment estimates the priority of pre-reserving service requests for resource allocation and measures the urgency of pre-reserving service requests for resource allocation.

[0078] The method for calculating the priority of pre-reserved business requests for resource allocation is as follows:

[0079] RS(C r H t ) = slots r ×Ht (3),

[0080] Among them, RS(C r H t To reserve priority for resource allocation for business requests in advance, slots r H is the number of spectral gaps required. t This indicates the duration of the business request. Business requests with shorter maximum tolerable latency are more urgent for resource allocation and are given higher priority for processing.

[0081] The method for calculating the urgency of resource allocation for pre-reserved service requests is as follows:

[0082]

[0083] Among them, TU(t) a ,td max To reserve resources in advance to account for the urgency of service requests, t a It is the arrival time of the business request, td max This represents the maximum tolerable delay time for a service request. a1 and a2 are preset coefficients. In this embodiment, a1 = 0.01 and a2 = 0.01.

[0084] To more accurately reflect the priority of service requests for resource allocation in C+L band elastic optical networks and optimize resource allocation, a priority evaluation function SP(C) is used. r ,t a H t ,td max The priority of a pre-reserved service request for resource allocation in a two-dimensional time-frequency resource model is represented by ), whereby the priority of the pre-reserved service request for resource allocation is specifically as follows:

[0085] SP(C r ,t a H t ,td max ) = RS(C r H t )×TU(t a ,td max (5),

[0086] Among them, SP(C r ,t a H t ,td max RS(C) indicates the priority of reserving service requests for resource allocation in advance. r H t ) represents the estimated resource allocation requirement for pre-reserved service requests, TU(t) a,td max This indicates the urgency of reserving business requests in advance for resource allocation.

[0087] Figure 4 The example demonstrates the priority evaluation of three sets of reserved service requests. According to formula (5), the priority evaluation value SP for R1 is: The priority evaluation value SP for R2 is The priority evaluation value SP for R3 is A higher SP value indicates a higher priority for resource allocation. For immediate reservation requests, resources are allocated immediately upon request arrival, resulting in the highest SP value and priority. For advance reservation requests, resources are allocated based on SP values, prioritizing higher-priority requests. If no available resources are available, the request is added to the reassignment request set and awaits secondary allocation according to priority. The SP value reflects the impact of capacity requirements, arrival time, and request duration on resource usage for advance reservation requests, while also considering the urgency of resource allocation, thereby optimizing network resource allocation and improving network resource utilization efficiency.

[0088] S4: In a C+L band flexible optical network, spectrum allocation must meet two constraints: the spectrum slots allocated for each service request must be continuous (i.e., spectrum continuity), and the same spectrum slots must be allocated on all fiber links of the selected optical channel (i.e., spectrum consistency). The modulation format for the current service request is selected based on the transmission distance. In this embodiment, the transmission distance is used to select the modulation format using an adaptive method as shown in Table 1. The average level of all modulation formats is calculated, and the application of a higher-order or lower-order modulation format for the current service request is determined based on the average level. Since the C-band in a flexible optical network increases the impact of ISRS on the L-band, if a higher-order modulation format is used, the last-hit method is used for spectrum allocation in the C-band to reduce C-band spectrum occupancy. Conversely, if a lower-order modulation format is used, the first-hit method is used for spectrum allocation in the L-band.

[0089] Calculate the average level of all modulation formats, and determine whether the current service request should apply a higher-order or lower-order modulation format based on the average level. Specifically:

[0090] The average level for all modulation formats is calculated as follows:

[0091]

[0092] Among them, M ave The average level is represented by m[i], where m[i] represents the modulation level corresponding to the i-th modulation format, and n represents the total number of modulation formats.

[0093] If the modulation level corresponding to the modulation format of the current service request is greater than the average level M ave If the modulation format is high, then a higher-order modulation format should be used; otherwise, a lower-order modulation format should be used.

[0094] In this embodiment, it is assumed that all service requests are transmitted from source node 1 to destination node 4. The average modulation format level is calculated by formula (6). BPSK and QPSK are low-order modulation formats, while 8-QAM and 16-QAM are high-order modulation formats. The link weight is calculated based on the two-dimensional time-frequency resource model. Route optimization is performed. Based on the total transmission distance of the selected path 3 being 300km, the modulation format during the service request resource allocation process is 16-QAM, where m=4. Therefore, spectrum allocation should be performed in the C-band. The purpose of this selection is to reduce ISRS interference between the C-band and L-band.

[0095] S5: If the current business request is an immediate reserved business request, since the tolerable latency is zero, i.e., td max =0, determine the arrival time t of the business. a Check if there are enough available spectrum resources. If not, block immediately. If there are, execute S6.

[0096] If the current service request is a pre-reserved service request within the maximum tolerable latency time, the service request will be continuously reallocated until there are enough available spectrum resources to carry the current service request, and then S6 will be executed.

[0097] S6: Calculate the optical signal-to-noise ratio (SNR) of the currently available spectrum resources by combining the amplifier spontaneous emission noise power and nonlinear noise power of the current service request. When the SNR is higher than the preset threshold, select the spectrum resource corresponding to the highest SNR to establish a service connection; otherwise, block it immediately.

[0098] This invention effectively compensates for fiber attenuation by placing erbium-doped fiber amplifiers (EDFAs) at a certain distance along the fiber optic link between node pairs. However, this compensation method also introduces amplifier spontaneous emission noise (ASE). Furthermore, addressing the issue of decreased optical signal-to-noise ratio (OSNR) in C+L band flexible optical networks, the transmission quality of the system is evaluated using OSNR, and nonlinear interference (NLI) caused by interband interactions is analyzed. The method for calculating the optical signal-to-noise ratio is as follows:

[0099]

[0100] Among them, OSNR rLet P be the optical signal-to-noise ratio of the currently available spectrum resource corresponding to the current service request r, and let P be the transmit power of the current service request. In this embodiment, it is assumed that each service request r has the same transmit power P, and the fiber link loss is fully compensated by EDFA. This represents the amplifier's spontaneously radiated noise power for the current service request r. This represents the nonlinear noise power of the current service request r.

[0101] The method for calculating the nonlinear noise power of the current service request r is as follows:

[0102]

[0103] in, This represents the working path of the current business request r from the source node s to the destination node d. For any path among the candidate working paths For the current service request r, there is interference on the fiber optic link in segment l. This refers to the interchannel interference of the current service request r on the l-th fiber optic link. Intrachannel interference refers to interference occurring within the same channel, also known as intra-channel interference; interchannel interference refers to interference occurring between different channels, also known as inter-channel interference.

[0104] The spectrum allocation strategies in S4–S6 keep used spectrum slots compact. When these slots are released, the released spectrum is relatively continuous. For subsequent service requests, these continuous spectrum slots are more likely to meet spectrum continuity requirements, thereby improving spectrum availability. Furthermore, it reduces the impact of C-band on L-band ISRS, thus improving OSNR tolerance.

[0105] When a service request arrives and spectrum is allocated on the C-band of path 3, the signal-to-noise ratio (SNR) of the available spectrum resource space is calculated using formulas (7) and (8). The higher the SNR, the higher the transmission quality of the service request in the link. The SNR value reflects the impact of noise generated by the service request during link transmission on the initial signal, and simultaneously considers ASE noise and nonlinear noise, thereby optimizing the transmission quality of network resources.

[0106] This invention also discloses a C+L EON resource optimization system based on service priority and signal-to-noise ratio, comprising:

[0107] The elastic optical network initialization module is used to initialize the C+L band elastic optical network and set up optical amplifiers on the optical fiber links of the C+L band elastic optical network.

[0108] The business request acquisition module is used to acquire the current business request and calculate the required number of spectrum slots and candidate working paths for the current business request.

[0109] The service request priority calculation module is used to determine whether the current service request is an immediate reservation service request or a pre-reserved service request based on the maximum tolerable latency time of the service request. If it is a pre-reserved service request, the priority of the pre-reserved service request for resource allocation is calculated based on the required number of spectrum slots.

[0110] The spectrum allocation band selection module is used to select the modulation format of the current service request based on the transmission distance, calculate the average level of all modulation formats, and determine whether the current service request should apply a high-order modulation format or a low-order modulation format based on the average level. If it is a high-order modulation format, the last hit method is used to allocate spectrum in the C band; if it is a low-order modulation format, the first hit method is used to allocate spectrum in the L band.

[0111] The spectrum allocation module is used to determine whether there are enough available spectrum resources at the time of service arrival if the current service request is an immediate reserved service request. If not, it will block. If the current service request is an advance reserved service request within the maximum tolerable delay time, it will continuously reallocate the service request until there are enough available spectrum resources to carry the current service request.

[0112] The service connection establishment module is used to calculate the optical signal-to-noise ratio (OSR) of the currently available spectrum resources by combining the amplifier spontaneous emission noise power and nonlinear noise power of the current service request. When the OSR is higher than a preset threshold, the spectrum resource corresponding to the highest OSR is selected to establish a service connection; otherwise, the connection is blocked.

[0113] The present invention also discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements a C+LEON resource optimization method based on service priority and signal-to-noise ratio.

[0114] The present invention also discloses an apparatus including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a C+LEON resource optimization method based on service priority and signal-to-noise ratio.

[0115] This invention primarily addresses the routing and spectrum allocation issues for real-time and advance reservation service requests in C+L band elastic optical networks. The scheduling of real-time reservation service requests only involves the spectrum dimension, while advance reservation service requests require consideration of both time and spectrum dimensions. Therefore, considering the characteristics of advance reservation service requests, this invention utilizes a two-dimensional time-frequency resource model to comprehensively consider factors such as consumed resources, affected resources, spectrum boundary distance, and start time. By minimizing the corresponding indicators, it better selects spectrum resources for advance reservation service requests. Furthermore, service request duration awareness provides additional information, reducing the probability of service request blocking by predicting information for each future request. This invention can optimize the signal-to-noise ratio of each request, ensuring that service requests in the network receive high-quality service during transmission, especially for high-priority requests, reducing interference and latency, and ensuring more stable network performance. Compared with existing technologies, the advantages of this invention are as follows:

[0116] 1. This invention assesses the resource allocation priority of different reserved service requests by comprehensively considering capacity requirements, service request arrival time, duration, and maximum tolerable latency. This ensures timely processing of high-priority service requests, more accurately reflects the priority of service requests in C+L band elastic optical networks, and more comprehensively evaluates the actual network resource needs of each service request. It avoids resource allocation based solely on time sequence or other static methods, thus achieving more comprehensive and accurate resource allocation. This method combines a tolerable latency reallocation method with a resource allocation priority scheduling strategy, maintaining resource status information in both the frequency and time domains to achieve the goal of simultaneously processing different reserved service requests in C+L band elastic optical networks. It can ensure timely response to immediate reserved service requests while rationally allocating resources for pre-reserved service requests, thereby achieving efficient resource utilization, optimizing network performance, and enabling the network to respond more flexibly and efficiently to different types and priorities of service requests. This maximizes network resource utilization, improves network survivability, and ensures stable network operation under various traffic surges or network failures, meeting ever-growing user demands.

[0117] 2. As the optical fiber link's band range extends from the C-band to the C+L-band, stimulated Raman scattering (SERS) occurs between channels, generating ASE noise during signal amplification. With the coexistence of ASE noise and SERS noise, the signal undergoes a certain degree of attenuation during transmission. Signal-to-noise ratio (SNR) is a crucial indicator of the transmission quality of flexible optical networks. As the bandwidth occupied by the optical fiber link increases and the transmission distance increases, the impact of SERS on the optical fiber link becomes increasingly significant. Therefore, it is necessary to prioritize optical fiber links with more available continuous optical fiber systems and shorter transmission distances. Thus, this invention, when transmitting along the selected optimal path, adjusts the modulation format according to the transmission distance and adaptively allocates spectrum to the C-band or L-band. Simultaneously, it selects the spectrum resource block with the highest SNR for allocation. This optimizes spectrum resource allocation while improving the overall network performance, ensuring the network can provide high-quality service even in complex service request environments.

[0118] 3. To improve the transmission quality of service requests, this invention primarily optimizes against ASE noise and nonlinear noise. It reduces the ISRS impact between the C-band and L-band by adaptively adjusting the modulation format. Simultaneously, it identifies spectrum blocks with the highest signal-to-noise ratio (SNR) from all available spectrum resources. This adaptive SNR method more comprehensively reflects the mutual influence and constraints between the C+L bands on network resources, thereby optimizing transmission quality and reducing signal attenuation of service requests while improving resource utilization efficiency.

[0119] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0120] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1A device that provides the functions specified in one or more boxes.

[0121] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0122] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0123] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A C+L EON resource optimization method based on service priority and signal-to-noise ratio, characterized in that, include: Initialize the C+L band elastic optical network and set up optical amplifiers on the optical fiber links of the C+L band elastic optical network; Obtain the current business request, and calculate the required number of spectrum slots and candidate working paths for the current business request; Based on the maximum tolerable latency of the service request, determine whether the current service request is an immediate reservation service request or an advance reservation service request. Combine the required number of spectrum slots, the duration of the service request, the arrival time of the service request, and the maximum tolerable latency of the service request to calculate the priority of the advance reservation service request for resource allocation. The modulation format of the current service request is selected based on the transmission distance. The average level of all modulation formats is calculated. Based on the average level, it is determined whether the current service request should use a high-order modulation format or a low-order modulation format. If it is a high-order modulation format, the last hit method is used to allocate the spectrum in the C-band. If it is a low-order modulation format, the first hit method is used to allocate the spectrum in the L-band. If the current service request is an immediate reserved service request, determine whether there are enough available spectrum resources at the service arrival time. If not, block. If the current service request is an advance reserved service request within the maximum tolerable delay time, continuously reallocate service requests until there are enough available spectrum resources to carry the current service request. The optical signal-to-noise ratio (OSR) of the currently available spectrum resources is calculated by combining the amplifier spontaneous emission noise power and nonlinear noise power of the current service request. When the OSR is higher than a preset threshold, the spectrum resource corresponding to the highest OSR is selected to establish a service connection; otherwise, the connection is blocked.

2. The C+L EON resource optimization method based on service priority and signal-to-noise ratio according to claim 1, characterized in that: The method for calculating the required number of spectral gaps is as follows: Among them, slots r For the required number of spectral gaps, C r This represents the capacity of the current service request, Δ is the base bandwidth of the spectrum slot, GB represents the spectrum slot bandwidth for protecting the service request, and m is the modulation level determined based on the actual physical transmission distance of the current service request.

3. The C+LEON resource optimization method based on service priority and signal-to-noise ratio according to claim 1, characterized in that: The duration of the service request is set to be an integer multiple of the unit time slot, and the actual start time for spectrum allocation of the service request is after the initial arrival time to schedule resource space. The instant reservation service request and the advance reservation service request are respectively: Where R represents the set of business requests, and the current business request is represented by r(s,d,t). a ,td max H t f) represents, where s represents the source node, d represents the destination node, and t represents the destination node. a It is the arrival time of the business request, td max H represents the maximum tolerable latency for a business request. t The duration of the service request is represented by f, and the required spectrum slot capacity is represented by f. The service request r represents the service request from source node s to destination node d, where r(s,d,t) is the service request from source node s to destination node d. a ,td max H t f)∈R; IR represents immediate reserved service request, AR represents advance reserved service request, t s This indicates the actual start time of the service request for spectrum allocation.

4. The C+LEON resource optimization method based on service priority and signal-to-noise ratio according to claim 1, characterized in that: The priority of the pre-reserved service requests for resource allocation is as follows: SP(C r ,t a H t ,td max ) = RS(C r H t )×TU(t a ,td max ), where SP(C r ,t a H t ,td max RS(C) indicates the priority of reserving service requests for resource allocation in advance. r H t ) represents the estimated resource allocation requirement for pre-reserved service requests, TU(t) a ,td max This indicates the urgency of reserving business requests in advance for resource allocation.

5. The C+LEON resource optimization method based on service priority and signal-to-noise ratio according to claim 4, characterized in that: The RS(C) r H t The calculation method for ) is as follows: RS(C r ,H t )=slots r ×H t , Among them, slots r H is the number of spectral gaps required. t Indicates the duration of the business request.

6. The C+LEON resource optimization method based on service priority and signal-to-noise ratio according to claim 4, characterized in that: The TU(t) a ,td max The calculation method for ) is as follows: Among them, t a It is the arrival time of the business request, td max This represents the maximum tolerable delay time for a business request, where a1 and a2 are preset coefficients.

7. The C+LEON resource optimization method based on service priority and signal-to-noise ratio according to claim 1, characterized in that: The calculation of the average level of all modulation formats, and the determination of whether the current service request applies a high-order modulation format or a low-order modulation format based on the average level, specifically involves: The average level for all modulation formats is calculated as follows: Among them, M ave The average level is represented by m[i], where m[i] represents the modulation level corresponding to the i-th modulation format, and n represents the total number of modulation formats. If the modulation level corresponding to the modulation format requested by the current service is greater than the average level, then the higher-order modulation format shall be applied; otherwise, the lower-order modulation format shall be applied.

8. The C+L EON resource optimization method based on service priority and signal-to-noise ratio according to any one of claims 1-7, characterized in that: The optical signal-to-noise ratio is calculated as follows: Among them, OSNR r Let P be the optical signal-to-noise ratio of the currently available spectrum resources corresponding to the current service request, and let P be the transmit power of the current service request. This indicates the amplifier's spontaneously radiated noise power in the current service request. This represents the nonlinear noise power of the current service request.

9. The C+L EON resource optimization method based on service priority and signal-to-noise ratio according to claim 8, characterized in that: The method for calculating the nonlinear noise power of the current service request is as follows: in, This represents the working path of the current business request from the source node s to the destination node d. For the current service request, there is interference on the fiber optic link in segment l. Inter-channel interference for the current service request on the l-th fiber optic link.

10. A C+L EON resource optimization system based on service priority and signal-to-noise ratio, characterized in that, include: The elastic optical network initialization module is used to initialize the C+L band elastic optical network and set up optical amplifiers on the optical fiber links of the C+L band elastic optical network. The business request acquisition module is used to acquire the current business request and calculate the required number of spectrum slots and candidate working paths for the current business request. The service request priority calculation module is used to determine whether the current service request is an immediate reservation service request or a pre-reserved service request based on the maximum tolerable latency time of the service request. If it is a pre-reserved service request, the priority of the pre-reserved service request for resource allocation is calculated based on the required number of spectrum slots. The spectrum allocation band selection module is used to select the modulation format of the current service request based on the transmission distance, calculate the average level of all modulation formats, and determine whether the current service request should apply a high-order modulation format or a low-order modulation format based on the average level. If it is a high-order modulation format, the last hit method is used to allocate spectrum in the C band; if it is a low-order modulation format, the first hit method is used to allocate spectrum in the L band. The spectrum allocation module is used to determine whether there are enough available spectrum resources at the time of service arrival if the current service request is an immediate reserved service request. If not, it will block. If the current service request is an advance reserved service request within the maximum tolerable delay time, it will continuously reallocate the service request until there are enough available spectrum resources to carry the current service request. The service connection establishment module is used to calculate the optical signal-to-noise ratio (OSR) of the currently available spectrum resources by combining the amplifier spontaneous emission noise power and nonlinear noise power of the current service request. When the OSR is higher than a preset threshold, the spectrum resource corresponding to the highest OSR is selected to establish a service connection; otherwise, the connection is blocked.

Images