Optimization of spectrum sharing in optical line systems

Abstract

Systems and methods for optimizing spectrum sharing in an optical line system, comprising: assigning (302) a value to a spectrum for at least one optical fiber in the optical line system (100) having the spectrum shared by at least two users; determining (304) how to divide the spectrum between the at least two users using the policy and the allocation value of the spectrum; and causing (306) the division of the spectrum to be performed. The allocation value of the spectrum can be based on the information bearing capacity per second bandwidth. The assignment value of the spectrum takes into account a performance-to-frequency relationship, for example, such that two or more of the at least two users have different spectral amounts from each other.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to U.S. Provisional Patent Application No. 63 / 481,783, filed on January 26, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to optical fiber. More specifically, the present disclosure relates to systems and methods for optimizing spectrum sharing in optical line systems. Background Art

[0004] Spectrum sharing is an evolving business model. Sharing the capacity of a fiber optic cable between two or more users can be accomplished by selling spectrum or jointly purchasing fiber pairs. On the surface, it seems pretty straightforward - divide the available optical bandwidth into segments of spectrum and operate each segment as a virtual fiber pair. However, not all spectrum is equal, and the operational realities of buying and selling spectrum (in GHz) versus capacity (in Gb / s) are not widely understood. Spectrum sharing is common in submarine cable systems, but submarine cable systems are very expensive to build and operate. Notably, submarine fiber optic cables can change significantly over time due to aging of the fiber (e.g., underwater, hydrogen gas travels through the casing over time, which creates additional losses, and this loss can vary across the spectrum), waves can move the cable over time causing breaks, repeaters age and degrade performance, and simply replacing a repeater is expensive, etc. So in the example of two users sharing a fiber pair, a simple split may seem fair at first, but this can change. Summary of the invention

[0005] The present disclosure relates to systems and methods for optimizing spectrum sharing in optical line systems. The present disclosure includes techniques for assigning values ​​to spectrum in a spectrum sharing environment and exploring how variations in SNR over frequency and time affect these estimates. Representative spectrum is then used to illustrate the allocation of spectrum among users using equal capacity. Finally, the role of terminal technology and automation in spectrum sharing applications is discussed. Specifically, the operational complexity of spectrum sharing is discussed and clarified. The estimation of spectrum is first explored, and how this estimation varies over time. Then, examples of measured signal-to-noise ratio (SNR) curves are used to demonstrate different options for spectrum allocation. Next, a discussion is made on how submarine line terminal equipment (SLTE) technology can affect spectrum sharing decisions, and finally an observation is made on the role of automation and instrumentation in spectrum sharing. It is worth noting that while the optimization of spectrum sharing is described for submarine systems, those skilled in the art will recognize that the optimization can also be applied to terrestrial systems or any other type of fiber optic system that shares spectrum.

[0006] Traditional spectrum sharing approaches utilize transmit power equalization or end-to-end average power equalization to contain users in fixed partitions. Unfortunately, this produces suboptimal results and requires intervention at every cable system event (e.g., capacity change, fiber cut, etc.). Therefore, currently known static configurations severely limit the performance and operational dynamics of each partner (user). The value of the system and the value to the partners decreases over time. That is, the present disclosure attempts to "refresh" performance.

[0007] Specifically, the present disclosure describes optical control strategies for spectrum sharing or spectrum leasing and management systems for monitoring, alarming, and enforcing each strategy. The strategy coverage and one or more implementation methods of a spectrum sharing management controller on both the data plane and the control plane are described.

[0008] In various embodiments, the present disclosure includes a method having steps, a processing device (e.g., a management system) configured to implement these steps, and a non-transitory computer-readable medium storing instructions that, when executed, cause one or more processors to perform these steps. The steps include: for at least one optical fiber in an optical line system having a spectrum shared by at least two users, assigning a value to the spectrum; using a policy and the assigned value of the spectrum to determine how to divide the spectrum between the at least two users; and causing the division of the spectrum to be implemented.

[0009] The allocation value of the spectrum can be based on the information carrying capacity of the bandwidth per second. The allocation value of the spectrum takes into account the relationship between performance and frequency, so that two or more users of the at least two users have different spectrum amounts from each other. The division of the spectrum can be continuous, so that each user of the at least two users has a continuous spectrum amount. The division of the spectrum can be fragmented between each user of the at least two users.

[0010] The determination and implementation can be performed at system startup of the optical line system. The determination and implementation can be performed after the optical line system is started and after the optical line system has been running for a period of time, in the event of any one of performance degradation of the optical line system and system enhancement of the optical line system. The steps can also include monitoring the optical line system; and checking the partitioning of the spectrum using the policy to determine whether there is a violation of the policy due to any one of performance degradation of the optical line system and system enhancement of the optical line system.

[0011] The strategy can include one of: allocating spectrum bands to at least two users so that each band is equally suitable for channels with the highest baud rate at any line rate, allocating spectrum bands to at least two users so that each band is equally suitable for line rates with the same number of channels, and allocating spectrum bands to at least two users, wherein the bands equally contain the same maximum theoretical capacity based on an integral of frequency-dependent optical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure is illustrated and described herein with reference to the various drawings, wherein like reference numerals are used to represent like system components / method steps, and wherein:

[0013] Figure 1 is a spectrum diagram showing a contiguous spectrum sharing allocation among three users.

[0014] Figure 2 is a spectrum diagram showing decentralized spectrum sharing allocation among three users.

[0015] Figure 3 is the Riemann approximation of the generalized signal-to-noise ratio (GSNR) over the entire spectrum.

[0016] Figure 4 is a plot of example GSNR variation over time.

[0017] Figure 5 is a plot of the start of life (BOL) GSNR versus frequency (GSNR(f)) for a modern transatlantic uncompensated fiber pair.

[0018] Figure 6is a plot of the predicted end-of-life (EOL) GSNR(f) for this same fiber pair.

[0019] Figure 7 This is a graph of the relationship between BOL Shannon spectral efficiency (SE, in b / S / Hz) and frequency.

[0020] Figure 8 This is a graph of the EOL Shannon spectral efficiency (SE, in b / S / Hz) versus frequency.

[0021] Fig. 9 It is the equal Shannon capacity distribution diagram of 2 spectrum partitions, 3 spectrum partitions and 4 spectrum partitions at BOL.

[0022] Fig.10 It is the equal Shannon capacity distribution diagram of 2 spectrum partitions, 3 spectrum partitions and 4 spectrum partitions at EOL.

[0023] Fig.11 It is a graph showing the variation of bandwidth (BW) required for equal Shannon capacity between EOL and BOL for N=2, 3, and 4 frequency partitions.

[0024] Fig.12 The present invention is a flow chart of a process of allocating values ​​to spectrum in a spectrum sharing environment based on a policy and implementing a spectrum sharing environment by dividing the spectrum.

[0025] Fig.13 It is a network diagram of an optical line system including management system, terminal equipment and line system.

[0026] Fig.14 is a network diagram of an optical line system showing connections between a management system and terminal devices for monitoring strategies.

[0027] Fig.15 A network diagram of an optical line system showing connections between a management system and a line system for performing (ie partitioning).

[0028] Fig.16 is a flow chart illustrating the process of partitioning, deploying, monitoring, and enforcing policies on a shared spectrum using spectrum value allocation.

[0029] Fig.17 is a spectrum diagram showing a deployment strategy, where various rules are used to allocate spectrum.

[0030] Fig.18 is a flow chart of the process of dividing the spectrum based on value. DETAILED DESCRIPTION

[0031] Likewise, the present disclosure relates to systems and methods for optimizing spectrum sharing in optical line systems. The present disclosure includes techniques for assigning values ​​to spectrum in a spectrum sharing environment and exploring how variations in SNR over frequency and time affect these estimates. Representative spectrum is then used to illustrate the allocation of spectrum among users using equal capacity. Finally, the role of terminal technology and automation in spectrum sharing applications is discussed. Specifically, the operational complexity of spectrum sharing is discussed and clarified. First, the estimation of spectrum is explored, and how that estimation varies over time. Then, examples of measured signal-to-noise ratio (SNR) curves are used to demonstrate different options for spectrum allocation. Next, SLTE (submarine line terminal equipment) technology is discussed to influence spectrum sharing decisions, and finally the role of automation and instrumentation in spectrum sharing is observed.

[0032] This disclosure includes:

[0033] (1) A method to develop the capability to highly customize shared network configurations based on several objectives, where each objective forms an operational policy.

[0034] (2) This method is not subject to the variability and uncertainty associated with nonlinear optical effects because the power spectral density (PSD) and optical loading remain constant throughout the operation.

[0035] (3) A methodology that is not limited to network elements and their performance. A single external controller actively adapts to the enhancements or deficiencies of partner terminals.

[0036] (4) Capacity equivalence strategies and partitioning rules across partners can be developed without the need to understand any or all intermediate components in the system.

[0037] Spectrum Sharing

[0038] Figure 1 It shows three users C 1 , C 2 , C 3 Spectral diagram of the continuous spectrum sharing allocation between. Figure 2 It shows three users C 1 , C 2 , C 3 Spectral diagram of decentralized spectrum sharing allocation between. The present disclosure relates to systems and methods for optimizing spectrum sharing channel configurations in optical line systems and managing individually leased spectrum partitions. Spectrum sharing and / or leasing has become a popular business model for operators of terrestrial and submarine line systems. For example, submarine line systems are generally costly, including high installation costs. Therefore, various service providers typically form a consortium to build and manage a submarine line system, wherein each service provider is allocated a portion of the submarine line system.

[0039] In this model, the operator or manager is responsible for the management of the line system and ensures that the allocated spectrum follows one or more control policies. The allocated spectrum may exist in continuous or fragmented bandwidth within the service-bearing passband. Figure 1 A continuous embodiment is shown in which C 1 , C 2 , C 3 Represents three (as an example) independent customers / partners (service providers). Figure 2 A decentralized implementation is shown in , where each partner allocates spectrum based on availability and / or preferred spectrum regions.

[0040] Spectrum estimation

[0041] The technology required to facilitate spectrum sharing utilizes multiplexing / demultiplexing techniques such as wavelength selective switches (WSS) and optical channel monitors (OCM). In submarine line systems, the terminals are called submarine line terminal equipment (SLTE), while in terrestrial line systems, the terminals are called reconfigurable optical add / drop multiplexers (ROADM). These network elements include various components for multiplexing / demultiplexing spectrum over optical fibers. Those skilled in the art will recognize that while the following description refers to submarine line systems, submarine networks, etc., the present disclosure contemplates implementation using any type of optical line system, including terrestrial line systems. However, spectrum sharing is not commercially mature and lacks widely accepted standardized definitions in many important aspects. One of these aspects is the valuation of spectrum, for example, to fairly allocate spectrum among multiple suppliers.

[0042] Traditionally, capacity, measured in bits per second (b / s), has been the primary technical metric used to define the commercial value of spectrum. Buying and selling capacity is not new, and the industry has developed techniques for specifying and valuing capacity commitments in commercial contracts.

[0043] In contrast, spectrum sharing focuses on the division of spectrum resources (measured in GHz) over optical fiber. This structure can be very useful because it separates the performance (and therefore the value) of the wet infrastructure (the optical line system with amplifiers, repeaters, branching units, etc.) from any specific terminal technology (i.e., terminal equipment such as modems). While this is in line with the industry direction of adopting the open cable paradigm, it is a departure from the traditional approach of dealing directly with capacity.

[0044] Spectrum and Capacity

[0045] This raises the important question of how spectrum is valued? While spectrum sharing applications focus on spectrum (GHz), relating this to information carrying capacity (Gb / s) enables the use of existing capacity valuation paradigms.

[0046] The SNR is a key factor in determining the fundamental limit in the information carrying capacity of a given communication channel. Specifically, the well-known Shannon-Hartley theorem provides a relationship between the SNR of a dual-polarized channel (in linear units), its bandwidth (B, in Hz), and the theoretical limit of capacity (C, in b / s) (see C.E. Shannon, "A mathematical theory of communication," Bell System Technical Journal, Vol. 27, No. 3, pp. 379-423, July 1948, doi: 10.1002 / j.1538-7305.1948.tb01338.x.):

[0047] .

[0048] However, the total SNR of a communication system includes both the channel and terminal components (i.e. both the cable and SLTE in the submarine case). This is neither consistent with the open cable paradigm nor with the valuation of the performance of the submarine cable itself. Therefore, it is recommended to use GSNR (generalized signal-to-noise ratio) to value the cable itself. GSNR includes both linear and nonlinear noise terms from wet facilities (ITU-T G.977.1 Recommendation for transversely compatible dense wavelength division multiplexing applications of trunked fibre submarine cable systems (2020)). In addition, it is usually assumed that there must always be a minimum margin, which can be accounted for in the capacity formula by adding the term "M" (linear units):

[0049] .

[0050] Equation (2) gives the relationship between the characteristic that can be characterized on a given cable (GSNR over bandwidth B) and the upper capacity limit assuming an ideal modem with margin M. This is a useful metric for valuing spectrum as it is completely independent of the SLTE technology. However, it is important to recognize that commercial SLTE technology cannot achieve the ultimate capacity defined by equation (1) in practice, and the difference between this upper limit and deployable solutions can be significant.

[0051] One option to reduce the gap between the predicted Shannon capacity and commercially achievable capacity is to use a margin of 3 dB (M = 2) in equation (2). This will not provide exact alignment for all technologies, but provides a rough guide for today’s state-of-the-art coherent modems.

[0052] Dependence on frequency

[0053] It is important to note that not all spectrum is equal. Submarine cables are large, complex analog devices, and admitting that performance varies with frequency is not new. For spectrum sharing, the main consequence is that GSNR will vary with frequency, and ultimately capacity will also vary with frequency. Therefore, for spectrum with bandwidth B, the capacity of the 1 With f 2 The capacity of a given portion between (whose SNR varies with SNR(f)) is given by:

[0054] .

[0055] However, it is usually not possible to define GSNR(f) analytically, nor is it possible to evaluate this integral analytically. Therefore, a practical approach is to approximate this integral by quantizing the spectrum into n blocks and adding the n blocks together, i.e., using the Riemann sum approximation:

[0056] .

[0057] This is Figure 3 It is shown in Figure 3 is the Riemann approximation of the generalized signal-to-noise ratio (GSNR) over the entire spectrum, and it is well known that this approximation increases with increasing values ​​of n, and that this approximation decreases with B i Close to zero and equal to the integral.

[0058] Evolution over time

[0059] In addition to the variation of GSNR with frequency, one must also consider how GSNR(f) varies with time. For example, during the design phase of cable construction, the user may only have access to nominal and / or worst-case GSNR values ​​without any details about spectral dependencies. However, at cable acceptance, this may change with a spectral scan measuring the Begin of Life (BOL) GSNR(f). Finally, as the cable ages, the End of Life (EOL) GSNR(f) may change due to repairs and other factors. This is particularly important in Figure 4 It is shown in Figure 4 is a plot of example GSNR variation over time.

[0060] As can be seen from this example, not only can the average GSNR of a cable vary over time, but the GSNR of specific parts of the spectrum can vary by more than that average.

[0061] This presents a challenge to both buyers and sellers when it comes to assigning a value to a particular piece of spectrum at a given point in time. Specifically, while Shannon capacity can be assigned based on GSNR and margin, buyers and sellers should agree on the meaning of the future guaranteed GSNR(f) for the spectrum in question to take into account the current and future value of the asset.

[0062] Spectrum Sharing Optimization Example

[0063] A framework for spectrum estimation using GSNR(f) and the Shannon capacity determined by the Riemann summation approximation is proposed. In this section, example BOL and EOL spectra are used to illustrate the process and demonstrate different options for splitting the spectrum.

[0064] Figure 5 A representative BOL GSNR versus frequency for a modern transatlantic uncompensated fiber pair is shown.

[0065] As an illustrative example, Figure 6 The predicted EOL GSNR(f) for this same fiber pair is shown. In this case, it is assumed that cable aging and repairs affect the average GSNR and tilt.

[0066] Using these GSNR(f) curves, the spectrum can be partitioned and the local Shannon capacity estimate can be calculated using equation (4). If divided by the width of the spectrum used (B i ), the local Shannon spectral efficiency (SE, in b / S / Hz) can be calculated as:

[0067] .

[0068] exist Figure 7 and Figure 8 The BOL and EOL conditions are shown in FIG.

[0069] Given any of these GSNR(f) graphs, how do you divide the spectrum among N different parties? In this case, there are multiple options for the optimization criteria, including: bandwidth, BOL capacity, EOL capacity, and the change in capacity from BOL to EOL.

[0070] Under each criterion, there is also a choice as to whether to distribute the asset equally among all parties (assuming equal value), or whether to bias spectrum allocations based on commercial negotiations with the parties.

[0071] Once the optimization criteria are agreed upon, both spectrum buyers and sellers can work to define a mutually agreeable spectrum allocation. For example, the spectrum will be divided into segments with equal capacity.

[0072] Equal Capacity Example

[0073] It is worth noting that the distribution of optical properties across the spectrum is not uniform, especially in underwater applications. Therefore, it is not straightforward to define continuous partitions by dividing the spectrum among N partners. Likewise, decentralized partitioning requires selective decisions to be made for each partner to ensure equal network capacity. The situation is further complicated by line system aging and maintenance. For example, Fig. 9 and Fig.10 Shown is how the partitioning of the passband evolves from the beginning of life (BOL) to the end of life (EOL). Performance was initially highest (at BOL) in the red band, and after aging, performance has degraded across the band, but now the blue band has higher spectral efficiency than the red band.

[0074] Fig. 9 and Fig.10 The following series of figures in show how the BOL and EOL systems defined by the above GSNR(f) curves can be divided into multiple segments with equal Shannon capacity. In this example, assuming that all spectrum is accessible (no filter dead zones), the spectral efficiency can be optimized with a granularity of 1 GHz (one of the advantages of assuming an ideal Shannon modem).

[0075] The legend for each figure details the spectrum boundaries required to balance capacity in each case. From these values, it can be seen that the difference in spectrum required to balance Shannon capacity at a given point in time is as high as 7.2% at BOL and only 3.4% at EOL (due to the narrower range of GSNR at EOL).

[0076] In contrast, if we observe how this equal-capacity partition changes between BOL and EOL, we get Fig.11 Here we can see that the red desired spectrum increases the most, while the blue decreases the most, and the mid-band changes the least overall, under both BOL and EOL conditions. This is consistent with a spectrum that tilts primarily between BOL and EOL.

[0077] This illustrates another dimension of spectrum inequality – the relative change in SNR (and therefore capacity and value) over time. While the future cannot be determined with certainty, the physics of aging cables often results in additional losses, which in turn cause tilt, further reducing SNR at lower frequencies. While this change can be mitigated by deploying repair repeaters, the key point is that this change needs to be planned for when negotiating the value of a given stretch of spectrum.

[0078] Value assignment process

[0079] Fig.12 The present invention is a flowchart of a process 10 for assigning a value to a spectrum in a spectrum sharing environment based on a policy and implementing a spectrum sharing environment by partitioning the spectrum. The process 10 is contemplated to be implemented as a method having steps, by a processing device configured to implement the steps and by instructions stored in a non-transitory computer-readable medium, which, when executed, causes one or more processors to perform the steps. The process 10 determines the value of the spectrum according to a given fairness criterion and ongoing operational value. Fairness does not necessarily mean 50% each, but can be any ratio agreed upon upfront (BOL), which may change until (EOL). In an embodiment, a fixed sharing value can be determined for the entire life cycle. In another embodiment, the sharing value may change over time taking into account operational factors. The present disclosure contemplates any commercial or contractual arrangement between users, and focuses on the value of such an arrangement over time taking into account the dynamic nature of optical fiber. Once the value of the spectrum is determined, it can be configured (manually or automatically) in a spectrum partitioning device (e.g., WSS, etc.) and a modem, transceiver, SLTE terminal, etc.

[0080] The process 10 includes: assigning a value to a spectrum on at least one optical fiber having a spectrum shared by at least two users (step 12); determining how the assigned value of the spectrum changes over time based on one or more measurement results and calculation results (step 14); and implementing a division of the spectrum between the at least two users based on the change over time (step 16). The process can be implemented for any optical line system (including submarine, terrestrial, etc.).

[0081] Spectrum Allocation Considerations

[0082] Given that different parts of the spectrum may experience different changes, and some parts of the spectrum may improve while others degrade, how can this be mitigated in a spectrum sharing solution?

[0083] In a shared spectrum system, spectrum allocation among N parties can be roughly divided into two categories: contiguous and decentralized. In the contiguous case, all spectrum allocated to a user is within a continuous frequency range. This is the easiest to imagine and is assumed in the examples in the previous section. This approach also minimizes the amount of spectrum wasted due to filter dead zones (filter dead zones are required whenever WSS is used to switch between ports, i.e., between spectrum segments allocated to different users), thereby maximizing the total capacity of the fiber pair. However, this approach also necessarily means that different users are restricted to different parts of the frequency band, and this can lead to inequalities in terms of SNR variations.

[0084] In the decentralized case, each user is allocated some spectrum from each different spectrum region (e.g., blue, middle, and red), resulting in multiple frequency regions for each user. This approach minimizes differences in spectrum behavior between users, but at the expense of reduced overall spectral efficiency due to the need for additional filter dead zones.

[0085] In either case, users should also consider how to respond to transient events that may be caused by other users changing their own spectrum content. Ideally, such transient events can be mitigated by clear rules around each user’s ability to manipulate the spectrum, and by spectrum sharing features such as policing. However, even though from a commercial perspective a shared fiber pair can be viewed as N independent virtual fiber pairs, it is still a single shared analog medium.

[0086] Examples of regulation are described in U.S. Patent No. 9,853,762, issued on December 26, 2017, entitled “Automated provisioning and control of shared optical spectrum in submarine optical networks,” the entire contents of which are incorporated herein by reference.

[0087] Impact of terminal technology

[0088] It was discussed how the upper limit defined by the Shannon-Hartley capacity formula can be used to value spectrum independently of SLTE technology. However, when calculating the actual capacity expected for a given spectrum sharing application, the specific terminal technology planned for a given deployment must be taken into account.

[0089] SLTE Photonics

[0090] With regard to SLTE photonics, the ability to operate on a truly flexible grid is a key attribute. While commercial agreements may choose to set frequency boundaries on well-defined grids (such as the 50GHz ITU grid), the boundaries calculated for a given optimization criterion are unlikely to fall on these frequencies. Therefore, flexible grid terminals are needed to access all available spectrum and maximize the value of each user's share. The second key photonic attribute is to minimize spectrum waste. This applies both to the filter dead zones required for WSS technology and to the selected multiplexer / demultiplexer (Mux / Demux) structure.

[0091] SLTE Modem

[0092] SLTE modem technology also plays a key role in spectrum sharing applications. For example, current commercially deployable solutions will not reach the upper limit of Shannon capacity definition. The achievable capacity will be affected not only by modem performance (modem noise and implementation), but also by the performance quantization caused by discrete client rate and / or baud rate options.

[0093] Spectrum performance (and potentially spectrum allocations) change over time, so it is valuable to have a modem that can adapt to the changing needs of users and provide an optimized solution over the lifecycle of a shared spectrum application. This makes flexible baud rates and flexible client rates key features to optimize modem performance. This allows users to optimize the net capacity on their spectrum without being constrained by potentially wasteful fixed channel spacing.

[0094] Not only do modem performance and flexibility impact the achievable capacity for a given application, but instrumentation and automation are also key attributes in a shared spectrum environment (see D. Boertjes, “Perspectives and Challenges on the Next Generation of Autonomous Networks,” OSA Technical Digest (Optica Publishing Group, 2020), paper NeM2B.1).

[0095] SLTE Automation

[0096] There may be a great spectrum sharing plan for a given cable system, but instrumentation and automation are key to successful execution. Modem instrumentation is critical to characterizing cable performance in the field, and SLTE automation is needed to obtain this characterization in an efficient and timely manner.

[0097] Specifically, accurate and efficient measurement of GSNR vs. frequency enables a clear and objective assessment of shared spectrum solutions. This is important at all stages post-deployment, including cable acceptance, after major cable events / repairs, and during spectrum ownership changes.

[0098] Once the measurement data is obtained, automated analysis can help define the spectrum boundaries and Shannon capacity based on the selected optimization criteria.

[0099] Example Optical Line System

[0100] Fig.13 is a network diagram of an optical line system 100 including a management system 102 , terminal equipment 104 , and a line system 106 . Fig.14is a network diagram of an optical line system 100 showing connections between a management system 102 and terminal devices 104 for monitoring policies. Fig.15 1 is a network diagram of an optical line system 100, showing the connection between a management system 102 and a line system 106 for enforcement (i.e., division). For the purpose of illustration, the optical line system 100 is shown as a submarine system, wherein the terminal equipment 104 is located at a cable landing, etc., and the line system 106 includes a wet facility 110 having cables and various repeaters (i.e., optical amplifiers), etc. (omitted for the purpose of illustration). Those skilled in the art will recognize that the submarine system is just one example in which spectrum sharing can be achieved. Land systems in which the line system 106 is separated from the terminal equipment, as well as other optical line systems are also considered. For example, the terminal equipment 104 in the submarine system is referred to as an SLTE device, and those skilled in the art will recognize that the terrestrial equivalent equipment is referred to as an optical add-drop multiplexer (OADM), a reconfigurable OADM (ROADM), a wavelength division multiplexing (WDM) terminal, etc. In contrast, the line system 106 in the terrestrial system can be simply referred to as the line side with amplifiers, etc., rather than a "wet facility" in the submarine system.

[0101] Those skilled in the art will recognize that the management system 102, the terminal device 104, and the line system 106 each consider various components for implementing the same functions in a submarine system, a land system, etc. In general, the management system 102 is a computing system implemented by one or more servers, clusters, etc. and the cloud. The management system 102 focuses on monitoring operations, performing configuration of various components, and general operations, management, maintenance, and provisioning (OAM&P) functions. The management system 102 can operate as a high-level controller and interact with a network management system (NMS) 112 associated with the terminal device 104 and the line system 106. For example, the terminal device 104 and the line system 106 may include equipment from different vendors and therefore have different management systems. In addition, due to spectrum sharing, the terminal device 104 may also generally come from different vendors. In a typical deployment, the management system 102 that implements spectrum sharing division, deployment, monitoring, and execution can communicate with various different NMSs, etc. via a northbound interface, an open application programming interface (API), etc.

[0102] The terminal device 104 is configured to perform optical-electrical-optical (OEO) conversion, multiplexing / demultiplexing and amplification. The terminal device 104 includes a transceiver (TR) 120, also known as a transmitter / receiver, a modem, a coherent modem, a pluggable optical module, a repeater, etc. Each transceiver 120 can be multiplexed / demultiplexed by a multiplexer / demultiplexer 122 and a wavelength selective switch (WSS) 124, and finally amplified by an optical amplifier 126, and then connected to the line system 106. Those skilled in the art will recognize that there can be various multiplexing / demultiplexing methods. For example, the multiplexer / demultiplexer 122 can combine multiple channels from multiple TRs 120 into subsets of the spectrum, for example, to create a media channel (MC). WSS124 can combine multiple subsets of the spectrum, etc. In this example, there are N SLTE components, namely SLTE 1, SLTE 2, ..., SLTE N (N is a positive integer). In this context, there are N users (ie, service providers) sharing a spectrum via a line system 106. The purpose of the terminal device 104 is to provide a channel in the spectrum allocated, assigned, or divided on the line system 106.

[0103] The line system 106 includes a spectrum sharing terminal 130 and an open cable interface (OCI) 132 leading to the wet facility 110. The spectrum sharing terminal 130 can be implemented as a WSS and other optical components, and its function is to enforce the allocation, assignment or division of spectrum for each user (i.e., SLTE 1-SLTE N) on the line system 106. Similarly, one embodiment of the spectrum sharing terminal 130 is described in U.S. Patent No. 9,853,762, entitled "Automated provisioning and control of shared optical spectrum in submarine optical networks", issued on December 26, 2017, the entire contents of which are incorporated herein by reference.

[0104] Optimization of spectrum sharing in optical line systems

[0105] The process 10 described herein utilizes a method of assigning values ​​to the spectrum to divide the spectrum based on policy. The process 10 is expected to be implemented at a certain point in time, such as initial deployment, after a period of operation, when conditions change, etc. It is recommended that the assigned values ​​be used throughout the life cycle and deployment of the optical line system 100. That is, the optical line system 100 will be described below from initial engineering and planning to deployment, and then to operation over time. The goal is to ensure that the allocated spectrum (partitioned spectrum) is fair according to the policy.

[0106] Fig.16Flowchart of process 200 for partitioning, deploying, monitoring, and enforcing policies for a shared spectrum using spectrum value assignments. Process 200 contemplates implementation of a method having steps, by a processing device configured to implement the steps and instructions stored on a non-transitory computer-readable medium, which, when executed, cause one or more processors to perform the steps. Specifically, process 200 is described from the perspective of a management system 102 in communication with an optical line system 100, but implementation in other ways is also contemplated.

[0107] The purpose of process 200 is to divide the spectrum among N users according to a predefined strategy, either continuously and / or decentralized (step 202). Dividing means that the spectrum is broken up so that each of the N users has some assigned value. These values ​​can be equal or unequal. The key is that the users agree on it beforehand. The division can be continuous (e.g., Figure 1 ) and / or decentralized (e.g. Figure 2 ). The purpose of the partitioning step 202 is to allocate the spectrum based on the optical or transceiver performance monitored by the management system 102. According to the strategy, unique frequency partitions and / or frequency groups are determined based on the optical performance curves of the entire frequency band. It is worth noting that partitioning is typically a static step that is performed once in the planning and engineering of the optical line system 100. The present disclosure contemplates making the partitioning step 202 dynamic, with the management system 102 re-evaluating over time based on life cycle monitoring to perform dynamic partitioning. Based on this monitoring, the partitioning step 202 takes into account re-evaluation, where fair partner requirements are implemented by actively expanding and / or compressing frequency partitions and / or frequency allocations over time. As described herein, frequency partitions and / or frequency allocations are the same as the partitioning of the spectrum.

[0108] Once the spectrum is divided, process 200 includes deploying the divided spectrum (step 204). Deployment step 204 includes configuring terminal devices 104 and / or line systems 106. For example, deployment step 204 can include configuring spectrum sharing terminals 130. In an embodiment, deployment step 204 can include allocating spectrum bands to N users in line system 206 such that each band is equally suitable for the highest baud rate (R) channel at any line rate (G) defined or undefined by the occupier. In another embodiment, spectrum bands are allocated to N users in line system 206 such that each band is equally suitable for the line rate (G) of the same number of channels. In another embodiment, spectrum bands are allocated to N users in line system 206, wherein the bands equally contain the same maximum theoretical capacity based on a continuous or discrete integral of frequency-dependent optical performance. Of course, any combination or superposition of the above methods can be used in deployment step 204. For example, Fig.17is a spectrum diagram for illustrating the deployment of a strategy for allocating spectrum using various rules.

[0109] After the deployment step 204, the process 200 includes monitoring the operation of the divided spectrum over time based on the policy (step 206). The management system 102 can build and store any optical knowledge using end-to-end performance monitors (PMs) of current traffic or non-traffic bearing channels. This data can be obtained during the commissioning calibration phase, field trials, or pre-deployment activities all associated with the optical line system 100. In one embodiment, an open interface is used to capture performance monitoring (PM) data after deployment and / or commissioning. The open interface is standardized. The management system 102 can provide a database of PMs to a spectrum sharing policy controller, which can be part of the management system 102 or can be implemented separately.

[0110] After the monitoring step 206, the process 200 includes enforcing the policy by changing the divided spectrum (step 208). This can include re-implementing the division step 202. The goal is to make some adjustments to the allocated spectrum when changes occur that make the policy no longer fair. The execution step 208 can include pushing system-level changes to a partner network management system (NMS) through an open API based on the division, deployment, and monitoring policy steps. In this article, the goal is to trigger spectrum boundary or partition expansion and / or compression based on performance degradation or system enhancement.

[0111] Process 200 contemplates dynamically performing monitoring step 206 and executing step 208 during the lifetime of the system or transient changes, such that spectrum allocations are proactively reallocated when new partners are added and / or partners are removed. Partitioning step 202 and deployment step 204 contemplate operations at system planning, engineering, installation, and startup. Monitoring step 206 and executing step 208 can be performed periodically based on system changes, etc. In addition, executing step 208 can be configured to change configurations only when threshold changes are met.

[0112] Value-based spectral partitioning process

[0113] Fig.18Flow chart of process 300 for dividing spectrum based on value. Process 300 is expected to be implemented as a method with steps, and by a processing device configured to implement the steps, and by instructions stored in a non-temporary computer-readable medium, when these instructions are executed, one or more processors are caused to implement these steps. Specifically, process 300 is described from the perspective of management system 102 that communicates with optical line system 100, but it is also expected to be implemented in other ways. In addition, process 300 is described from the perspective of a single point in time, that is, how to use the assigned values ​​at any given point in time to fairly divide the spectrum based on strategy. "Fairly" means that the spectrum is divided according to an agreed-upon strategy. As described herein, the value of the spectrum may change over time due to a variety of factors.

[0114] Process 300 includes: for at least one optical fiber in an optical line system having a spectrum shared by at least two users, assigning a value to the spectrum (step 302); using a policy and the assigned value of the spectrum to determine how to divide the spectrum between the at least two users (step 304); and enabling the division of the spectrum to be implemented (step 306). As described herein, the policy is agreed upon by the at least two users. For example, the at least two users can be equal partners, with each user obtaining the same amount of bandwidth. Other approaches may also be considered.

[0115] The allocated value of the spectrum is based on the information carrying capacity of the bandwidth per second. The allocated value of the spectrum takes into account the relationship between performance and frequency so that two or more of the at least two users have different amounts of spectrum from each other. Therefore, the allocated value is more accurate than an equal division of the spectrum.

[0116] In an embodiment, the division of the spectrum is continuous, so that each of the at least two users has a continuous amount of the spectrum. In another embodiment, the division of the spectrum is decentralized between each of the at least two users. In another embodiment, the division can be a combination of continuous and decentralized.

[0117] In an embodiment, the determination and implementation can be performed at the system startup of the optical line system. In another embodiment, the determination and implementation can be performed after the system startup and after the optical line system has been running for a period of time, in the case of any one of the performance degradation of the optical line system and the system enhancement of the optical line system.

[0118] The process 300 can also include monitoring the optical line system; and checking the partitioning of the optical spectrum using the policy to determine if there is a violation of the policy due to any of a performance degradation of the optical line system and a system enhancement of the optical line system.

[0119] The strategy can include one of: allocating spectral bands to at least two users so that each band is equally suitable for channels with the highest baud rate at any line rate, allocating spectral bands to at least two users so that each band is equally suitable for line rates with the same number of channels, and allocating spectral bands to the at least two users, wherein the bands equally contain the same maximum theoretical capacity based on an integral of frequency-dependent optical performance.

[0120] In another embodiment, the management system 102 includes a network interface connected to terminal devices from at least two users and a line system, the line system and the terminal devices from the at least two users forming an optical line system; one or more processors communicatively coupled to the network interface; and a memory storing instructions that, when executed, cause the one or more processors to implement the process 300. The implementation is implemented by configuring any one of the terminal devices from the at least two users and the line system.

[0121] in conclusion

[0122] A method for assigning a value to spectrum in a spectrum sharing environment using Shannon capacity is proposed, and how variations in SNR over frequency and time affect this estimate is explored. Representative spectrum is then used to illustrate the allocation of spectrum among users using equal capacity. In addition, the role of terminal technology and automation in spectrum sharing applications is discussed. Finally, it is described how the management system 102 uses this assigned value to partition, deploy, monitor, and deploy optical line systems 100 with spectrum partitioned based on policies.

[0123] It should be understood that some embodiments described herein may include one or more general or special processors ("one or more processors"), such as: a microprocessor; a central processing unit (CPU); a digital signal processor (DSP); a custom processor, such as a network processor (NP) or a network processing unit (NPU), a graphics processing unit (GPU), etc.; a field programmable gate array (FPGA); and a processor with a unique storage program instruction (including software and firmware) for controlling the instruction to implement some, most or all functions of the method and / or system described herein in combination with certain non-processor circuits. Alternatively, some or all functions may be implemented by a state machine that does not store program instructions, or in one or more application-specific integrated circuits (ASICs), where each function or some combination of certain functions is implemented as a custom logic or circuit. Of course, a combination of the above methods may be used. For some embodiments described herein, the corresponding devices of the hardware and optional software, firmware and combinations thereof can be referred to as "configured or adapted circuits", "configured or adapted logic", etc., to perform operations, steps, methods, processes, algorithms, functions, techniques, etc. as described herein for various embodiments on digital and / or analog signals.

[0124] In addition, some embodiments may include a non-transitory computer-readable storage medium having computer-readable code stored thereon for programming a computer, server, appliance, device, processor, circuit, etc., each of which may include a processor to perform the functions described and claimed herein. Examples of such computer-readable storage media include, but are not limited to, hard disks, optical storage devices, magnetic storage devices, read-only memories (ROMs), programmable read-only memories (PROMs), erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), flash memory, etc. When stored in a non-transitory computer-readable medium, software can include instructions executable by a processor or device (e.g., any type of programmable circuit or logic) that, in response to such execution, cause the processor or device to perform operations, steps, methods, processes, algorithms, functions, techniques, etc. as described herein for various embodiments.

[0125] Although the present disclosure has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to one of ordinary skill in the art that other embodiments and examples may perform similar functions and / or achieve similar results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure, are contemplated hereby, and are intended to be covered by the following claims. The foregoing section includes the headings of the various embodiments, and it will be understood by those skilled in the art that these various embodiments may be used in conjunction with one another or may be used alone.

Claims

1. A method (300) comprising the following steps: For at least one optical fiber in an optical line system (100) having a spectrum shared by at least two users, assigning (302) a value to the spectrum; determining (304) how to divide the spectrum between the at least two users using a policy and the allocation values ​​of the spectrum; as well as This enables the partitioning of the (306) spectrum to be implemented.

2. The method (300) according to claim 1, wherein: The spectrum is allocated based on its information carrying capacity per second of bandwidth.

3. The method (300) according to claim 1, wherein: The assigned values ​​of the spectrum take into account the relationship between performance and frequency, so that two or more of the at least two users have different spectrum quantities from each other.

4. The method (300) according to any one of claims 1 to 3, wherein: The division of the spectrum is continuous, so that each of the at least two users has a continuous amount of spectrum.

5. The method (300) according to any one of claims 1 to 3, wherein: The division of the spectrum is decentralized between each of the at least two users.

6. The method (300) according to any one of claims 1 to 5, wherein: The determining and the implementing are performed at system startup of the optical line system.

7. The method (300) according to any one of claims 1 to 5, wherein: The determining and the implementing are performed after the system of the optical line system is started and the optical line system is operated for a period of time, in the event of any one of performance degradation of the optical line system and system enhancement of the optical line system.

8. The method (300) according to any one of claims 1 to 7, wherein: The steps also include monitoring the optical line system; as well as The partitioning of the optical spectrum is checked using the policy to determine if there is a violation of the policy due to degradation of the optical line system.

9. The method (300) according to any one of claims 1 to 7, wherein: The steps also include monitoring the optical line system; as well as The partitioning of the optical spectrum is checked using the policy to determine if there is a violation of the policy due to system enhancements of the optical line system.

10. The method (300) according to any one of claims 1 to 9, wherein: The strategy includes allocating spectrum bands to the at least two users such that each band is equally suitable for a channel of the highest baud rate at any line rate.

11. The method (300) according to any one of claims 1 to 10, wherein: The strategy includes allocating spectrum bands to the at least two users such that each band is equally suitable for line rates of the same number of channels.

12. The method (300) according to any one of claims 1 to 11, wherein: The strategy includes allocating spectrum bands to the at least two users, wherein the bands equally contain the same maximum theoretical capacity based on an integration of frequency-dependent optical performance.

13. A management system (102), comprising: A network interface connected to a line system and terminal devices from at least two users, the line system and the terminal devices from at least two users forming an optical line system (100); as well as One or more processors configured to implement the method (300) according to any one of claims 1 to 12.

14. An optical line system (100) comprising a light spectrum managed based on the method (300) according to any one of claims 1 to 12.

15. Computer readable code for programming one or more processors to implement the method (300) according to any one of claims 1 to 12.

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