CN112969108B - Resource allocation method with low crosstalk influence - Google Patents

Abstract

The invention discloses an efficient resource allocation method with low crosstalk influence, and belongs to the technical field of multi-dimensional optical networks. The method firstly adopts the resource-aware routing modulation format coordination method based on the minimum crosstalk to plan the resource-minimizing path for the service; then dynamically establishes the crosstalk influence auxiliary map according to the current resource occupancy status of the network, and compares the frequency slots corresponding to the available spectrum blocks on all cores. The degree of fluctuation affected by the crosstalk; finally, the core and spectrum resources where the spectrum block with the least fluctuation degree is located are allocated to the service. The method effectively reduces the influence of crosstalk between cores in the network, reduces service congestion, and achieves the purpose of efficiently utilizing the network spectrum resources by rationally allocating spectrum resources.

Description

A Resource Allocation Method with Low Crosstalk Impact

technical field

The present invention relates to the technical field of multi-dimensional optical networks, in particular to an efficient resource allocation method with low crosstalk influence.

Background technique

With the rapid development of cloud computing, big data, and Internet of Things technologies, Internet traffic has grown rapidly, and the optical network as the underlying support is facing huge challenges. As an effective means to improve the transmission capacity of Elastic Optical Networks (EONs), space division multiplexing technology based on Multi-Core Fiber (MCF) has attracted widespread attention. The spatial dimension is introduced into EONs to form a multi-dimensional optical network. Considering that Inter-Core Crosstalk (IC-XT) is an important constraint of MCF, it is necessary to effectively avoid IC-XT through a reasonable resource allocation method to maximize the Realize the multi-dimensional optical network to carry services, thereby reducing the congestion of services and improving the utilization of network spectrum resources.

In the current literature, the IC-XT problem cannot be effectively avoided in the network, which is not conducive to the efficient utilization of spectrum resources in the network. Interfering with the business, this method overestimates the impact of IC-XT in the network, so that the allocation method based on this cannot be well adapted to the real-time network resource status; 2) Only from the business point of view to explore their mutual interference effects, lack of Comprehensive perception of the impact of IC-XT in the network, and overall planning of network spectrum resources based on this.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides an efficient resource allocation method with low crosstalk impact. The present invention firstly adopts the resource-aware routing modulation format coordination method based on the minimum crosstalk, and realizes the minimization of the influence of IC-XT through the planning of the modulation format and the path, thereby reducing the service congestion; secondly, the present invention adopts the core spectrum allocation scheme based on the fluctuation degree of the influence of the crosstalk. , to achieve the balance of the influence of IC-XT in the network, and achieve the purpose of efficiently using the network spectrum resources.

In order to achieve the above-mentioned purpose, the technical solution adopted in the present invention is: an efficient resource allocation method with low crosstalk impact, comprising the following steps:

S1: According to the source node and the sink node of the new service request, perform routing calculation on the new service, and obtain its K shortest paths;

S2: Use the resource-aware routing modulation format coordination method based on the minimum crosstalk to plan several candidate paths for the new service;

S3: Find available spectrum blocks on all fiber cores of the current candidate path that meet the frequency slot resources required by the new service and the crosstalk restriction;

S4: Calculate the fluctuation degree of the influence of the inter-core crosstalk of the available spectrum blocks in turn, and allocate the core and spectrum resources where the spectrum block with the least fluctuation degree is located for the new service, so as to establish a connection.

Further, the method for calculating the K shortest paths in the step S1 is the KSP Dijkstra shortest path method.

Further, the resource-aware routing modulation format coordination method based on the minimum crosstalk in the step S2 specifically includes the following steps: traversing the K shortest paths in turn, and determining the highest available modulation format level according to the current shortest path length; The current shortest path constitutes a collaborative candidate path; the frequency slot resources required by the new service on each candidate path are calculated; the shortest path traversal is completed, and all candidate paths are sorted in ascending order according to the size of the frequency slot resources required by the new service;

Further, the calculation method of the frequency slot resource required by the service is:

n _p =|l|×f _l

M={M ₁ ,M ₂ ,...M _i ...,M _max }

Among them, n _p is the frequency slot resource required by the service on the candidate path p, |l| is the number of links of the candidate path p, f _l is the frequency slot number required by the service on the link l, and b is the service request , C is the unit capacity of a frequency slot, M _i is the modulation format level of the service on the current candidate path, and M is the set of available modulation format levels of the service on the current shortest path.

Further, the step S3 specifically includes the following steps: traverse all the candidate paths in turn, and find available spectrum blocks on all fiber cores of the current candidate path that meet the frequency slot resources required by the new service and the crosstalk restriction; if the current candidate path has available spectrum blocks; If there is no available spectrum block in the current candidate path, search for the next candidate path; if there is no available spectrum block in all candidate paths, the traversal ends and the current service is blocked.

Further, the crosstalk limit value is determined by the modulation format level of the new service on the current candidate path. Different modulation format levels correspond to different crosstalk limit values. The higher the modulation format level, the smaller the crosstalk limit value.

Further, in the step S4, the calculation method of the degree of crosstalk influence fluctuation is:

d _p =∑ _l∈p d _l

为平均串扰影响值，f_l为业务在链路l上所需的频隙数。Among them, d _p is the fluctuation degree of the available spectrum blocks on the candidate path p affected by the inter-core crosstalk, d _l is the fluctuation degree of the available spectrum blocks on the link l, and s is the set of frequency slot sequences where the available spectrum blocks are located , xt _j is the crosstalk influence value of frequency slot j,

is the average crosstalk impact value, and f _l is the number of frequency slots required by the service on link l.

The present invention adopts the above-mentioned high-efficiency resource allocation method with low crosstalk influence, and the beneficial effects are as follows:

1. The present invention uses the routing modulation format coordination planning method to ensure that the service affects the resources at the same position of the adjacent fiber cores with the minimum number of frequency slots on the premise of satisfying the crosstalk restriction. This resource-aware routing modulation format coordination method realizes the effect of crosstalk. Minimized, effectively reducing service congestion.

2. In the multi-dimensional optical network resource configuration, the present invention dynamically establishes an auxiliary graph of crosstalk influence in the network, and allocates resources with the least fluctuation degree of crosstalk influence to services. The effect of medium crosstalk is balanced, and to the greatest extent, the situation where continuous idle resources cannot be used due to the large influence of crosstalk in a single frequency slot is avoided, and the purpose of efficiently utilizing network resources is achieved.

Description of drawings

1 is a flowchart of an embodiment of the present invention;

Fig. 2 is a kind of multi-dimensional optical network based on seven-core MCF;

Fig. 3 is the spectrum resource occupancy situation of services in 7 fiber cores on a link in the multi-dimensional optical network of Fig. 2;

FIG. 4 is an auxiliary diagram of the influence of inter-core crosstalk on spectrum resources on the link in FIG. 3 .

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, an efficient resource allocation method with low crosstalk impact includes the following steps:

S1: After the new service request arrives, KSP Dijkstra algorithm is used to calculate K shortest paths P _k for it according to the service source and sink node request information, and each shortest path consists of l links respectively;

S2: Use the resource-aware routing modulation format coordination method based on the minimum crosstalk to plan an appropriate path for the service: traverse P _k in turn _, and determine the highest available modulation format level M _max for the service according to the path length of P _k ; _k constitutes a cooperative candidate path, and calculates the frequency slot resources required by the service on each candidate path; according to the size of the frequency slot resources required by the new service, all candidate paths p are arranged in ascending order;

S3: traverse the candidate paths p in turn, and find the frequency slot resources and crosstalk restrictions required by the service on all the cores of the candidate path p _i (corresponding to the modulation format level of the new service on the candidate path p _i , the higher the modulation format level is , the smaller the value of the crosstalk limit is), the available spectrum blocks are recorded in array B. If the array B is not empty, go to step S4; if the array B is empty, traverse the next candidate path p _i+1 ;

S4: Calculate the crosstalk influence fluctuation degree D of each available spectrum block in the array B in turn, and select the fiber core and spectrum resource where the available spectrum block with the smallest D value is located for the service, so as to establish a connection.

The specific method of step S2 is:

Determine the highest available modulation format level M _max according to the path length of P _k , all modulation format levels M={M ₁ , M ₂ ,...,M _i ,...,M _max }, each level of modulation level M _i and P _k constitute a Cooperate with the candidate paths to calculate the total number of frequency slots n _p required by the service in turn:

n _p =|l _p |×f _l

where |l _p | is the number of links of the candidate path p _i , f _l is the number of frequency slots required on the link l _p , b is the data rate requested by the service, C is the unit capacity of a frequency slot, M _i is the corresponding modulation format level of the candidate path _pi .

The specific method of step S4 is:

Auxiliary diagram of crosstalk impact in dynamically established networks: Since IC-XT is related to whether the same position of adjacent cores on a link is occupied, this auxiliary diagram shows the number of adjacent fiber cores currently occupied at this frequency slot position , and express this value as the influence of inter-core crosstalk at this position, then the calculation method of the fluctuation degree based on the influence of this inter-core crosstalk is:

d _p =∑ _l∈p d _l

为平均串扰影响值，f_l为业务在链路l上所需的频隙数。Among them, d _p is the fluctuation degree of the available spectrum block on the candidate path p _i affected by the inter-core crosstalk, d _l is the fluctuation degree of the crosstalk effect of the available spectrum block on the link l, and s is the frequency slot sequence where the available spectrum block is located. Set, xt _j is the crosstalk influence value of frequency slot j,

is the average crosstalk impact value, and f _l is the number of frequency slots required by the service on link l.

An example of the calculation process of the influence of the inter-core crosstalk on the fluctuation degree is as follows:

Figure 2 shows a typical seven-core MCF structure. In this structure, except for the middle core, the other cores are adjacent to three cores. Figure 3 shows the occupancy of spectrum resources of services in 7 cores on a link. Different shadings indicate that the spectrum resources are occupied by different services, and the positions without shading are idle spectrum resources.

According to the current resource occupancy, an auxiliary diagram of the influence of inter-core crosstalk is dynamically established. As shown in Figure ₄ , the number on each frequency slot in the figure is the value of the crosstalk affected. The degree of crosstalk influence fluctuation is:

To sum up, the present invention comprehensively senses the influence of crosstalk between cores in a multi-dimensional optical network, adopts a resource-aware routing modulation format coordination method based on the minimum crosstalk, and a core spectrum allocation scheme based on the degree of fluctuation of the influence of crosstalk, to coordinate the network spectrum resources. planning. Among them, in the resource-aware routing modulation format coordination method based on the minimum crosstalk, a resource-minimizing path is planned for the service to ensure that the influence of the current inter-core crosstalk is minimized. In the core spectrum allocation scheme based on the degree of crosstalk influence fluctuation, an auxiliary diagram of crosstalk influence in the network is dynamically established, and the resources with the least fluctuation degree of frequency slot crosstalk corresponding to the available spectrum blocks on all cores are allocated for the service, and the inter-core crosstalk is realized. Equalization avoids the situation that idle spectrum blocks cannot be used due to excessive influence of crosstalk between cores of a single frequency slot in future networks. The method effectively reduces the influence of inter-core crosstalk in the network by reasonably allocating spectrum resources, reduces service congestion, and achieves the purpose of efficiently utilizing network spectrum resources.

The above are specific embodiments of the present invention, but the protection scope of the present invention should not be limited thereto. Any changes or substitutions that any person skilled in the art can easily think of within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention, so the protection scope of the present invention should be limited by the claims The scope of protection shall prevail.

Claims (5)

1. A resource allocation method with low crosstalk influence is characterized by comprising the following steps:

s1: according to the source node and the destination node of the new service request, carrying out routing calculation on the new service to obtain K shortest paths;

s2: planning a plurality of candidate paths for a new service by adopting a resource-aware routing modulation format cooperation method based on the minimum crosstalk; the resource-aware routing modulation format coordination method based on the minimum crosstalk specifically comprises the following steps: sequentially traversing K shortest paths, and determining the highest available modulation format grade according to the length of the current shortest path; each level of modulation format grade and the current shortest path form a collaborative candidate path; calculating frequency slot resources required by the new service on each candidate path; completing the shortest path traversal, and arranging all candidate paths in an ascending order according to the size of frequency slot resources required by the new service;

s3: searching available frequency spectrum blocks which meet frequency gap resources and crosstalk limitation required by a new service on all fiber cores of a current candidate path;

s4: sequentially calculating the influence fluctuation degree of the crosstalk among cores of the available spectrum blocks, and distributing the fiber core and the spectrum resource where the spectrum block with the minimum fluctuation degree is located to the new service so as to establish connection; the method for calculating the fluctuation degree of the crosstalk influence comprises the following steps:

d_p＝∑_l∈pd_l

wherein d is_pThe fluctuation degree of the influence of the interchip crosstalk on the available spectrum block on the candidate path p, d_lThe fluctuation degree of crosstalk influence of the available spectrum block on the link l, s is the set of frequency slot sequences where the available spectrum block is located, xt_jFor the value of the crosstalk influence experienced by frequency slot j,

is an average crosstalk influence value, f_lThe number of frequency slots needed on link l for traffic.

2. The method for allocating resources with low crosstalk influence according to claim 1, wherein the calculation method for calculating K shortest paths in step S1 is KSP Dijkstra shortest path method.

3. The method for allocating resources with low crosstalk influence according to claim 1, wherein the method for calculating the frequency slot resources required by the service comprises:

n_p＝|l|×f_l

M＝{M₁，M₂，...M_i...，M_max}

wherein n is_pFor the frequency slot resource needed by the service on the candidate path p, | l | is the link number of the candidate path p, f_lThe number of frequency slots required on link l for a service, b the data rate requested for the service, C the unit capacity of a frequency slot, M_iThe modulation format class of the service on the current candidate path is M, and the modulation format class is the set of available modulation format classes of the service on the current shortest path.

4. The method for allocating resources with low crosstalk influence according to claim 1, wherein the step S3 specifically includes the steps of: traversing all candidate paths in sequence, and searching available frequency spectrum blocks which meet frequency gap resources and crosstalk limitation required by a new service on all fiber cores of the current candidate path; if the current candidate path has available spectrum blocks, go to step S4; if the current candidate path does not have an available frequency spectrum block, searching the next candidate path; and if all the candidate paths do not have available spectrum blocks, ending traversal and blocking the current service.

5. The method according to claim 4, wherein the crosstalk limiting value is determined by a modulation format class of a new service in the current candidate path, different modulation format classes correspond to different crosstalk limiting values, and a higher modulation format class results in a smaller crosstalk limiting value.

Images