CN113316036B - Dynamic wavelength bandwidth allocation method - Google Patents

Abstract

The present disclosure provides a dynamic wavelength bandwidth allocation method, which is applied to a time division wavelength division multiplexing passive optical network TWDM-PON. The TWDM-PON includes an optical line terminal OLT and a plurality of optical network unit ONUs. The ONU and the preempted ONU, as well as the preemption time and the retransmission time are determined, so that the preempted ONU transmits the fronthaul service at the preemption time, and the preempted ONU retransmits the occupied bandwidth resources at the retransmission time. The wavelength bandwidth allocation method can reduce the transmission delay of the fronthaul service.

Description

Dynamic wavelength bandwidth allocation method

technical field

The present disclosure relates to the technical field of electronic information, and in particular, to a dynamic wavelength bandwidth allocation method.

Background technique

In the scenario where the fixed network and the mobile network converge, two DWBAs (wavelength bandwidth allocation), ie, SR-DWBA and CO-DWBA, are usually combined to meet the requirements of different services (fixed and mobile).

In the same TWDM-PON (time and wavelength division multiplexed passive optical network, time division wavelength division multiplexing passive optical network) system, the effective cooperation of the two DWBA schemes is very important, and the cooperation is related to the DWBA period. The SR-DWBA period is affected by the PON transmission distance and the number of ONUs, and is generally not less than 1ms. The period of CO-DWBA is related to the length of the radio frame. In a 4G LTE network, the frame length/frame period, also known as TTI, is 1ms. The UE may obtain wireless bandwidth authorization information 4 TTIs (4ms) in advance. It can be seen from the above that the OLT also obtains the upstream data information 4ms in advance, and allocates the upstream bandwidth in the PON in advance. Since 4ms is greater than the period of SR-DBWA, there is no allocation conflict between the two for 4G fronthaul services.

However, 3GPP defines the new air interface (5G NR) of 5G mobile networks, and proposes the concept of mini-slot, which is similar to the concept of TTI in LTE, which represents the basic frame structure and scheduling period in wireless networks. The mini-slot specifies more subcarrier spacing, such as 15, 30, and 60 kHz, and fewer OFDM symbols, such as 2, 4, and 7. The length of mini-slot is less than the length of LTE TTI (1ms), which is more suitable for 5G low-latency services.

The related technology is carried out in the scenario where the TTI length is 1ms in the 4G network. Due to the shortening of mini-slot proposed in 5G NR, the CO-DWBA wireless scheduling period in the original scheme does not match the SR-DWBA polling authorization period. When authorizing for FTTH, only the mobile scheduling information of part of the mobile data within the current cycle length (1ms) is received, and the subsequent mobile data is not predictable, resulting in additional waiting delay when there is no idle wavelength bandwidth resource to be allocated in the OLT. Therefore, it cannot meet the low-latency transmission delay requirement of the mobile fronthaul service. That is to say, the wavelength bandwidth allocation scheme in the related art causes the transmission delay of the fronthaul service to be too high.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present disclosure is to propose a dynamic wavelength bandwidth allocation method.

Based on the above purpose, the present disclosure provides a dynamic wavelength bandwidth allocation method, which is applied to a time division wavelength division multiplexing passive optical network TWDM-PON; the TWDM-PON includes an optical line terminal OLT and a plurality of optical Network unit ONU; Described OLT is connected with a plurality of described ONUs; In described TWDM-PON, there are multiple wavelengths for transmitting service information;

The method includes:

The OLT determines the first ONU and the second ONU; the second ONU is the ONU assigned bandwidth corresponding to any of the wavelengths; the first ONU is to preempt the assigned the ONU of the bandwidth of the wavelength;

The OLT determines the preemption moment and the retransmission moment;

The OLT generates a preemption instruction according to the preemption moment and sends it to the first ONU; the preemption instruction is used to make the first ONU perform service transmission at the preemption moment;

The OLT generates a retransmission instruction according to the retransmission moment and sends it to the second ONU; the retransmission instruction is used to make the second ONU perform service transmission at the retransmission moment.

It can be seen from the above that the dynamic wavelength bandwidth allocation method provided by the present disclosure is applied to the time division wavelength division multiplexing passive optical network TWDM-PON, and the TWDM-PON includes an optical line terminal OLT and a plurality of optical network units The ONU determines the preempted ONU and the preempted ONU, as well as the preemption time and the retransmission time, so that the preempted ONU transmits the fronthaul service at the preemption time, and the preempted ONU retransmits the occupied bandwidth resources at the retransmission time. Through this preemptive wavelength bandwidth allocation method, the transmission delay of the fronthaul service is reduced.

Description of drawings

In order to illustrate the technical solutions in the present disclosure or related technologies more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only for the present disclosure. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic diagram of a fusion DWBA solution in the related art provided by an embodiment of the present disclosure;

2 is a schematic diagram of a conflict in bandwidth allocation in a CO-DWBA and SR-DWBA fusion scheme in the related art caused by a mini-slot provided in an embodiment of the present disclosure;

3 is a schematic flowchart of a dynamic wavelength bandwidth allocation method provided by an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a scenario of a dynamic wavelength bandwidth allocation method provided by an embodiment of the present disclosure;

5 is a schematic flowchart of a method for determining a second ONU according to an embodiment of the present disclosure;

6 is a schematic flowchart of a method for determining a third ONU according to an embodiment of the present disclosure;

7 is a more specific schematic diagram of a scenario of a dynamic wavelength bandwidth allocation method provided by an embodiment of the present disclosure;

8 is a schematic flowchart of a first ONU performing preemption according to an embodiment of the present disclosure;

FIG. 9 is a schematic flowchart of a second ONU performing retransmission according to an embodiment of the present disclosure.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the specific embodiments and the accompanying drawings.

It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should have the usual meanings understood by those with ordinary skill in the art to which the present disclosure belongs. "First", "second" and similar words used in the embodiments of the present disclosure do not denote any order, quantity or importance, but are only used to distinguish different components. "Comprises" or "comprising" and similar words mean that the elements or things appearing before the word encompass the elements or things recited after the word and their equivalents, but do not exclude other elements or things. Words like "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "Down", "Left", "Right", etc. are only used to represent the relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

This patent is directed to a time and wavelength division multiplexed passive optical network (TWDM-PON) system in a fixed-mobile network convergence scenario. A TWDM-PON includes an optical line terminal (OLT) and multiple optical network units (ONUs), wherein the OLT is connected to multiple ONUs. TWDM-PON has 4 wavelengths for transmission in each of the upstream and downstream directions; OLT has a receiver/transmitter that can receive and transmit multiple wavelengths; ONU has a tunable transmitter that can be modulated to any one of the 4 upstream wavelengths and a tunable receiver that can receive any of the 4 wavelengths downstream.

The dynamic wavelength bandwidth allocation (DWBA) method of the related art is divided into a low delay scheme and a high bandwidth utilization scheme. Among them, for the fixed access service, the traditional dynamic wavelength bandwidth allocation scheme based on request authorization (SR-DWBA) is mainly used, that is, the polling period is divided in the uplink transmission process, and the ONU sends the OLT to the OLT according to the buffered data in each period. To request upstream bandwidth, after the OLT collects bandwidth requests from all ONUs, it performs unified authorization in the next training cycle. This "request-grant" mechanism can effectively improve the utilization efficiency of bandwidth in the PON. For the mobile access service, the cooperation-based dynamic wavelength bandwidth allocation scheme (CO-DWBA) is adopted. The principle is to introduce information exchange between the mobile processing unit (CU/DU) and the OLT to realize wireless and optical cooperation, that is, in each wireless scheduling period (TTI), the CU/DU sends the wireless bandwidth authorization information to the mobile user. At the same time, the UE sends corresponding information to the OLT. In this way, the OLT can obtain the upstream bandwidth information of the mobile ONU (ONU connected to the mobile base station, called the mobile ONU) in advance, and authorize the upstream bandwidth of the mobile ONU according to the information. This scheme can greatly reduce the signaling transmission delay required by the request-authorization of SR-DWBA, and meet the requirement of low delay for mobile fronthaul.

In fixed and mobile network convergence scenarios, two DWBAs (SR-DWBA and CO-DWBA) are usually combined to meet different service (fixed and mobile) requirements. In the same TWDM-PON system, the effective cooperation of the two DWBA schemes is very important, and the cooperation is related to the DWBA cycle. The SR-DWBA period is affected by the PON transmission distance and the number of ONUs, and is generally not less than 1ms. The period of CO-DWBA is related to the length of the radio frame. In a 4G LTE network, the frame length/frame period, also known as TTI, is 1ms. The UE may obtain wireless bandwidth authorization information 4 TTIs (4ms) in advance. It can be seen from the above that the OLT also obtains the upstream data information 4ms in advance, and allocates the upstream bandwidth in the PON in advance. Since 4ms is greater than the period of SR-DBWA, there is no allocation conflict between the two for 4G fronthaul services.

3GPP defines the new air interface (5G NR) of 5G mobile networks, and proposes the concept of mini-slot, which is similar to the concept of TTI in LTE, and represents the basic frame structure and scheduling period in wireless networks. The mini-slot specifies more subcarrier spacings, such as 15, 30, and 60kHz, and fewer OFDM symbols, such as 2, 4, and 7. The length of mini-slot is less than the length of LTE TTI (1ms), which is more suitable for 5G low-latency services. However, 5G NR based on mini-slot will cause CO-DWBA and SR-DWBA to conflict in the resource allocation process, thereby increasing the delay of mobile fronthaul services.

Specifically, in the TWDM-PON system for fixed-mobile convergence, the OLT uses a combination of two DWBAs (SR-DWBA and CO-DWBA) to realize the connection between the fiber-to-the-home ONU (FTTH ONU) and the fronthaul ONU (Fronthaul ONU). enter.

As shown in (a) in Figure 1, the CO-DWBA cycle depends on the TTI length. In 4G LTE, the TTI length is 1ms. For the wireless data packet 1 of a TTI to be uploaded in the RU, the OLT will receive 4TTI (4ms) in advance. The radio resource authorization information (for example, the mobile scheduling information mobile-info in the figure) issued by the DU, according to this, performs wavelength bandwidth allocation for the ONU in advance. After that, the OLT will issue the authorization before the ONU receives the data uploaded by the RU. Therefore, the CO-DWBA period should be less than 4ms (the upper bound of the CO-DWBA period) to ensure that the wireless data arriving at the ONU does not need to wait for direct upload. .

As shown in (b) in Figure 1, SR-DWBA scheduling is based on the traditional polling method of requesting authorization, and the period depends on the maximum ONU round-trip distance RTT _max . The OLT collects all the ONU request messages at the time t _i-1 of the SR-DWBA cycle i-1 and then uniformly allocates the bandwidth, and sends the result to each ONU through the authorization message. When the ONU receives the authorization, it will upload the data according to the authorized window size at the start of the authorized transmission. In order to ensure that the OLT collects the request information of all ONUs before the start of cycle i, the cycle length should be greater than RTT _max . In addition, in order to meet the requirement of the number of ONUs carried by the OLT, the SR-DWBA period is generally not less than 1ms, for example, set to 2ms.

Since CO-DWBA and SR-DWBA have different cycle length requirements, the real DWBA cycle is usually divided into multiple small authorization cycles, and virtual CO-DWBA and SR-DWBA cycles are provided by combining multiple authorization cycles. In the existing scheme, the length of the CO-DWBA cycle is equal to the length of one TTI (TTI in (a) in Figure 1), and the lengths of the SR-DWBA cycle and the real cycle are set to be the same as the TTI length in 4G LTE (The SR-DWBA cycle in (b) in Figure 1). The cooperation of the two DWBAs is carried out in the real cycle, when the SR-DWBA receives the bandwidth request at time t _i-1 , the CO-DWBA has already received in advance the movement of information about the total amount of mobile data arriving in the SR-DWBA cycle i. Scheduling information (mobile-info), so when performing SR-DWBA, the first part of the bandwidth on each wavelength in the cycle can be reserved for the upcoming fronthaul service, and then the remaining bandwidth on each wavelength in the cycle can be based on the FTTH ONU. Bandwidth requests are allocated. The above solution combines the advantages of CO-DWBA and SR-DWBA, which can meet the low-latency transmission of fronthaul services and improve the resource utilization efficiency of PON, but the premise is that CO-DWBA should obtain bandwidth request information earlier than SR-DWBA. , that is to say, the period of CO-DWBA is greater than that of SR-DWBA.

The implementation of the related scheme mainly depends on the prediction of the total amount of wireless data in the current cycle by the OLT in advance of T _p , where the length of T _p is the time between the OLT receiving the cooperation information sent by the CU/DU and the ONU receiving the uploaded wireless data. interval. T _p depends on the downlink transmission delay of mobile data, and is related to the length of slot/TTI. As mentioned above, in 4G LTE, the value of T _p is 4TTI (ie, 4ms), that is, the OLT can predict the data volume of the fronthaul service after 4ms, and preferentially allocate wavelength and bandwidth to the service.

In 5G NR, different subcarrier spacings of 15, 30, and 60 kHz are used, and the number of OFDM symbols in each time slot is also changed from a fixed 14 to an optional length of 2, 4, and 7. Higher carrier spacing and fewer OFDM symbols result in a consequent reduction in slot length. As shown in Figure 2, the mobile data 1 transmitted based on the mini-slot can be uploaded to the ONU without waiting for the collection of subsequent mobile data 2 to n. Compared with the original RU that needs to receive all wireless data within the duration of 1msTTI and then upload it to the ONU, this mini-slot-based transmission strategy can reduce the latency of mobile fronthaul services.

However, as the time slot is shortened, the T _p associated with it is also shortened, even smaller than the SR-DWBA period. Therefore, the OLT receives the mobile schedule information (mobile-info) more than once in a real period. However, only the mobile-info received before the execution time of SR-DWBA (eg t _i-1 ) will be considered, and the bandwidth will be reserved according to the arrival time of the mobile data carried by it and the total amount of mobile data. For mobile-info arriving after the time of executing SR-DWBA, the bandwidth allocated by CO-DWBA will conflict with the bandwidth already allocated by SR-DWBA.

As shown in Figure 2, before time t _i-1 , the OLT receives the mobility scheduling information about the mobile data 1-m-1, and the CO-DWBA allocates the first half of the bandwidth in the period i for the mobile data 1-m-1. At time t _i-1 , the OLT receives the bandwidth request from the FTTH ONU, and the SR-DWBA allocates the remaining second half of the bandwidth in cycle i for the FTTH service. However, it can be seen from the above that the subsequent mobile data m~n will be received in the period i, and the calculation based on the shortened T _p shows that the mobile scheduling information corresponding to the mobile data m~n arrives at the OLT later than t _{i. -1} . Since the OLT misses the advance prediction of mobile data m~n at time t _i-1 and reserves wavelength bandwidth resources for it, the wavelength bandwidth allocated to it according to CO-DWBA is different from that previously allocated by SR-DWBA for FTTH services Wavelength bandwidth conflicts. In order to avoid resource conflict, the mobile data corresponding to the subsequent mobile scheduling information can only be uploaded in the idle bandwidth allocated at the end of the period, which increases the waiting delay of the fronthaul service in the ONU.

To sum up, the related scheme is carried out in the scenario where the TTI length is 1ms in the 4G network. Due to the shortened mini-slot proposed in 5G NR, the CO-DWBA wireless scheduling period in the original scheme does not match the SR-DWBA polling authorization period. When the OLT authorizes the FTTH, it only receives the mobile scheduling information of part of the mobile data within the current cycle length (1ms), and has no predictability for the subsequent mobile data, resulting in extra waiting time when there is no idle wavelength bandwidth resource to be allocated in the OLT. Therefore, it cannot meet the low-latency transmission delay requirements of mobile fronthaul services. That is to say, the related wavelength bandwidth allocation scheme causes the transmission delay of the fronthaul service to be too high.

3 is a schematic flowchart of a dynamic wavelength bandwidth allocation method provided by an embodiment of the present disclosure; the dynamic wavelength bandwidth allocation method is applied to a time division wavelength division multiplexing passive optical network TWDM-PON; the TWDM-PON includes an optical line The terminal OLT is connected to multiple ONUs of optical network units; the OLT is connected to multiple ONUs; there are multiple wavelengths used to transmit service information in the TWDM-PON.

As an optional embodiment, the TWDM-PON has 4 wavelengths for transmission in the upstream and downstream directions; the OLT has a receiver/transmitter that can receive and transmit multiple wavelengths; the ONU has one that can be modulated into the 4 upstream wavelengths Any 1 tunable transmitter and a tunable receiver that can receive any 1 of the 4 downstream wavelengths.

Dynamic wavelength bandwidth allocation methods, including:

S310. The OLT determines the first ONU and the second ONU.

For each ONU, any one of the multiple wavelengths of the TWDM-PON can be used to transmit services, wherein the second ONU is an ONU assigned a bandwidth corresponding to any wavelength; the first ONU is to preempt the second ONU The ONU for the bandwidth of the wavelength to which the ONU is assigned.

When the first ONU needs to use the TWDM-PON wavelength to transmit the fronthaul service, the fronthaul service is a high-priority service. In order to ensure that the fronthaul service can be transmitted as early as possible, it is obviously not possible to queue up for transmission according to the existing transmission order. An ONU can choose to preempt the wavelength and bandwidth on the wavelength that has been allocated to other ONUs, and the preempted ONU is recorded as the second ONU. The first ONU and the fronthaul service information are known. Specifically, the fronthaul service information includes the preset transmission start time and bandwidth requirement of the fronthaul service, and the transmission end time can be calculated from the transmission start time and the bandwidth requirement.

The first ONU sends the request for transmitting the fronthaul service and the information of the fronthaul service to the OLT, and the OLT determines the preempted ONU, that is, the second ONU, according to the information of the fronthaul service.

The ONU sends the information to the OLT through the REPORT message; the OLT sends the information to the ONU through the GATE message. Optionally, the ONU sends the service information in the ONU, such as the fronthaul service information, to the OLT through the REPORT message. The REPORT message is a feedback mechanism used by the ONU to transmit the local status (such as the buffer occupancy, which can be understood as the bandwidth requirement of the ONU in this disclosure) to the OLT, and is used to help the OLT allocate time slots. Correspondingly, the GATE message is sent from the OLT to a single ONU to allocate a transmission time slot for the ONU. A time slot is represented by three values: transmission wavelength, transmission start time and transmission window length. Both the GATE message and the REPORT message are MAC control frames used in the TWDM-PON message exchange protocol.

S320. The OLT determines the preemption time and the retransmission time.

The transmission start time of the second ONU is taken as the preemption time. The second ONU is an ONU to which a bandwidth is allocated corresponding to any wavelength, that is, the transmission start time of the second ONU is known.

Wherein, according to the preemption time, the retransmission time can be calculated.

The retransmission time can be calculated by the following formula:

t _re = t _pre + t _date + t _guard ;

Among them, t _re is the retransmission time, t _pre is the preemption time, t _date is the duration of the first ONU transmission service, and t _guard is the guard interval.

S330. The OLT generates a preemption instruction according to the preemption time and sends it to the first ONU.

The preemption instruction is used to make the first ONU perform service transmission at the preemption moment.

S340. The OLT generates a retransmission instruction according to the retransmission time and sends it to the second ONU.

The retransmission instruction is used to make the second ONU perform service transmission at the retransmission moment.

Optionally, the OLT sends the instruction to the ONU through a GATE message.

The GATE message is sent from the OLT to a single ONU, and is used to allocate a transmission time slot for the ONU. A time slot is represented by three values: transmission wavelength, transmission start time, and transmission window length.

4 is a schematic diagram of a scenario of a dynamic wavelength bandwidth allocation method provided by an embodiment of the present disclosure; wherein, λ _k is the wavelength k, TX is the transceiver, t _pre is the preemption time, and t _realloc1 , t _realloc2 and t _realloc3 are three Retransmission time.

The dynamic wavelength bandwidth allocation method is implemented by the optical line terminal OLT that makes the preemption decision, the fronthaul ONU that receives the preemption command, and the fiber-to-the-home ONU that receives the preempted command. The fronthaul ONU and the fiber-to-the-home ONU respectively correspond to the first ONU and the second ONU. For unified expression, the present disclosure will be described with the first ONU and the second ONU (wherein the first ONU refers to the preempted ONU, that is, the fronthaul ONU; the second ONU refers to the preempted ONU, that is, the fiber-to-the-home ONU). Optionally, the OLT includes a DWBA controller and a receiver/transmitter λ _k TX that can receive and transmit multiple wavelengths. The DWBA controller executes wavelength bandwidth allocation (Wavelength bandwidth allocation, WBA) decisions, determines the first ONU and the second ONU, as well as the preemption time and the retransmission time, generates a preemption command according to the preemption time and sends it to the first ONU, and according to the retransmission time A retransmission command is generated and sent to the second ONU. Before the preemption moment, the second ONU transmits fiber-to-the-home data. The first ONU transmits the fronthaul service at the preemption moment. The second ONU retransmits the interrupted service at the retransmission moment.

FIG. 5 is a schematic flowchart of a method for determining a second ONU according to an embodiment of the present disclosure.

S510. Whether there is an assignable wavelength in the TWDM-PON.

In response to determining that an assignable wavelength exists in the TWDM-PON, the earliest available wavelength is granted, and the bandwidth and start time are assigned. In this case, there are idle wavelengths in the TWDM-PON, and there is no need to determine the second ONU to preempt the wavelength bandwidth allocated by the second ONU.

In the OLT, each wavelength corresponds to the next available transmission time of the wavelength, and the OLT records the next available transmission time of all wavelengths. When the OLT allocates a wavelength to the ONU, it selects the wavelength with the earliest available transmission time, and at the same time Authorize the transmission window of the ONU on this wavelength, and then update the next available transmission time of this wavelength. As for the size of the transmission window, it is determined by the bandwidth allocation algorithm. This process of bandwidth allocation is called the earliest available wavelength authorized.

S520. Whether there is an ONU that meets a preset preemption condition.

In response to determining that there are no assignable wavelengths in the TWDM-PON, a third ONU is determined corresponding to each wavelength.

The third ONU is an ONU that satisfies a preset preemption condition. In this case, there is no idle wavelength in the TWDM-PON, and the second ONU needs to be determined to preempt the wavelength bandwidth allocated by the second ONU. If there is no ONU that satisfies the preset preemption condition, the earliest available wavelength is authorized, and the bandwidth and start time are allocated, that is, queuing.

S530. Use the third ONU with the earliest transmission start time among the plurality of third ONUs as the second ONU.

The earliest third ONU at the start of transmission is the earliest preemptible ONU, and using it as the second ONU can reduce the delay of the first ONU transmitting the fronthaul service.

FIG. 6 is a schematic flowchart of a method for determining a third ONU according to an embodiment of the present disclosure.

S610. Determine the preset transmission start time of the first ONU.

The preset transmission start time of the first ONU is the earliest time that the first ONU can preempt.

S620. Determine a fourth ONU corresponding to each wavelength.

The fourth ONU is an ONU to which the bandwidth of the wavelength is allocated at and after the preset transmission start time of the first ONU. The fourth ONU is a candidate preempted ONU. The ONU that is transmitting services at the preset transmission start time of the first ONU is obviously the first target that the first ONU wants to preempt. If the ONU does not meet the preset preemption requirements condition, then, after the ONU transmits the service, the ONU that uses the wavelength to transmit the service will also become an alternative preempted target.

For each fourth ONU,

S630. Whether the fourth ONU has a high priority.

In response to determining that the fourth ONU has a high priority, the preempted queue is emptied, and the fourth ONU is re-determined, wherein the preempted queue contains at least one fourth ONU that does not have a high priority.

Wherein, redetermining the fourth ONU specifically includes: taking the next ONU corresponding to the wavelength corresponding to the fourth ONU as the redetermined fourth ONU.

S640. Whether the transmission end time of the fourth ONU is earlier than the preset transmission end time of the first ONU.

In response to determining that the fourth ONU does not have a high priority, it is further determined whether the transmission end time of the fourth ONU is earlier than the preset transmission end time of the first ONU:

In response to determining that the transmission end time of the fourth ONU is earlier than the preset transmission end time of the first ONU, the fourth ONU is put into the preempted queue, and the fourth ONU is re-determined. Wherein, redetermining the fourth ONU specifically includes: taking the next ONU corresponding to the wavelength corresponding to the fourth ONU as the redetermined fourth ONU.

In response to determining that the transmission end time of the fourth ONU is later than the preset transmission end time of the first ONU, the fourth ONU is placed in the preempted queue and all ONUs in the preempted queue are collectively used as the third ONU.

FIG. 7 is a schematic diagram of a more specific scenario of a dynamic wavelength bandwidth allocation method provided by an embodiment of the present disclosure. In the preemption method provided in this embodiment, corresponding to the method in FIG. 6 , except for high-priority services (fronthaul services), other services can be preempted, and cross-ONUs can also be preempted, so as to reduce the waiting delay of fronthaul services as much as possible. This preemption constraint is the most friendly to fronthaul services, but it will result in frequent preemption and more preemption fragments.

FIG. 8 is a schematic flowchart of a first ONU performing preemption according to an embodiment of the present disclosure, including:

Receive OLT authorization information;

In response to satisfying t _pre,k =t, send data directly according to the authorization information;

In response to not satisfying t _pre,k =t, wait for the authorization moment before sending the traffic.

FIG. 9 is a schematic flowchart of a second ONU performing retransmission according to an embodiment of the present disclosure, including:

The preemptive ONU performs block transmission at the wavelength bandwidth not occupied by the preempted ONU to avoid conflict with the preempted ONU. There are two cases for the transmission of the preempted ONU on an upstream frame, namely when only one t _realloc is received. Cached data only needs to be interrupted by one burst upload ONU and when multiple t _reallocs are received, the cached data needs to be divided into multiple burst upload ONUs to delay transmission.

It can be seen from the above that the dynamic wavelength bandwidth allocation method provided by the present disclosure is applied to the time division wavelength division multiplexing passive optical network TWDM-PON, and the TWDM-PON includes an optical line terminal OLT and a plurality of optical network units The ONU determines the preempted ONU and the preempted ONU, as well as the preemption time and the retransmission time, so that the preempted ONU transmits the fronthaul service at the preemption time, and the preempted ONU retransmits the occupied bandwidth resources at the retransmission time. Through this preemptive wavelength bandwidth allocation method, the transmission delay of the fronthaul service is reduced.

It should be noted that, the methods of the embodiments of the present disclosure may be executed by a single device, such as a computer or a server. The method in this embodiment can also be applied in a distributed scenario, and is completed by the cooperation of multiple devices. In the case of such a distributed scenario, one device among the multiple devices may only perform one or more steps in the method of the embodiment of the present disclosure, and the multiple devices will interact with each other to complete all the steps. method described.

It should be noted that some embodiments of the present disclosure are described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that in the above-described embodiments and still achieve desirable results. Additionally, the processes depicted in the figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

It should be noted that the embodiments of the present disclosure can also be further described in the following ways:

A dynamic wavelength bandwidth allocation method, wherein, it is applied in a time division wavelength division multiplexing passive optical network TWDM-PON; the TWDM-PON includes an optical line terminal OLT and a plurality of optical network units ONU; the OLT and A plurality of described ONUs are connected; There are multiple wavelengths for transmitting service information in the described TWDM-PON;

The method includes:

The OLT determines the first ONU and the second ONU; the second ONU is the ONU assigned bandwidth corresponding to any of the wavelengths; the first ONU is to preempt the assigned the ONU of the bandwidth of the wavelength;

The OLT determines the preemption moment and the retransmission moment;

The OLT generates a preemption instruction according to the preemption moment and sends it to the first ONU; the preemption instruction is used to make the first ONU perform service transmission at the preemption moment;

The OLT generates a retransmission instruction according to the retransmission moment and sends it to the second ONU; the retransmission instruction is used to make the second ONU perform service transmission at the retransmission moment.

Optionally, wherein, the OLT determines the first ONU and the second ONU, specifically including:

determining whether there is the wavelength that can be allocated in the TWDM-PON;

In response to determining that the assignable wavelength does not exist in the TWDM-PON, a third ONU is determined corresponding to each of the wavelengths; the third ONU is the ONU that meets the preset preemption condition; the The third ONU with the earliest transmission start time among the plurality of third ONUs is used as the second ONU.

Optionally, wherein the OLT determines the preemption moment and the retransmission moment, specifically including:

Taking the transmission start time of the second ONU as the preemption time;

According to the preemption time, the retransmission time is obtained by calculation.

Optionally, wherein, in response to determining that there is no assignable wavelength in the TWDM-PON, a third ONU is determined corresponding to each of the wavelengths, specifically including:

Determine the preset transmission start time of the first ONU;

Determine a 4th ONU corresponding to each described wavelength; Described 4th ONU is the described ONU that has been allocated the bandwidth of this wavelength at described preset transmission start time and later;

For each of the fourth ONUs,

determine whether the fourth ONU has high priority,

In response to determining that the fourth ONU has a high priority, the preempted queue is emptied, and the fourth ONU is re-determined, wherein the preempted queue includes at least one described fourth ONU that does not have a high priority,

In response to determining that the 4th ONU does not have a high priority, it is further determined whether the transmission end time of the 4th ONU is earlier than the preset transmission end time of the first ONU,

In response to determining that the transmission end time of this 4th ONU is earlier than the preset transmission end time of the first ONU, put this 4th ONU into the described preempted queue, re-determine the 4th ONU, in response to determining this The transmission end time of the 4th ONU is later than the preset transmission end time of the first ONU, and the 4th ONU is put into the preempted queue and all the ONUs in the preempted queue are collectively used as the described Third ONU.

Optionally, wherein, the re-determination of the fourth ONU specifically includes:

The next ONU corresponding to the wavelength corresponding to the fourth ONU is used as the re-determined fourth ONU.

Optionally, wherein, calculating the retransmission time according to the preemption time includes:

The retransmission time can be calculated by the following formula:

t _re = t _pre + t _date + t _guard ;

Among them, t _re is the retransmission time, t _pre is the preemption time, t _date is the duration of the first ONU transmission service, and t _guard is the guard interval.

It should be understood by those of ordinary skill in the art that the discussion of any of the above embodiments is only exemplary, and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples; under the spirit of the present disclosure, the above embodiments or Technical features in different embodiments may also be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the disclosed embodiments as described above, which are not provided in detail for the sake of brevity.

In addition, to simplify illustration and discussion, and in order not to obscure the embodiments of the present disclosure, well-known power/power sources associated with integrated circuit (IC) chips and other components may or may not be shown in the figures provided in the figures provided. ground connection. Furthermore, devices may be shown in block diagram form in order to avoid obscuring the disclosed embodiments, and this also takes into account the fact that details regarding the implementation of these block diagram devices are highly dependent on the implementation of the disclosed embodiments platform (ie, these details should be well within the understanding of those skilled in the art). Where specific details (eg, circuits) are set forth to describe exemplary embodiments of the present disclosure, it will be apparent to those skilled in the art that these specific details may be used without or with variations The embodiments of the present disclosure are implemented as follows. Accordingly, these descriptions are to be considered illustrative rather than restrictive.

Although the present disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations to these embodiments will be apparent to those of ordinary skill in the art from the foregoing description. For example, other memory architectures (eg, dynamic RAM (DRAM)) may use the discussed embodiments.

The disclosed embodiments are intended to cover all such alternatives, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present disclosure should be included within the protection scope of the present disclosure.

Claims (4)

1. a dynamic wavelength bandwidth allocation method, wherein, is applied in time division wavelength division multiplexing passive optical network TWDM-PON; In described TWDM-PON, comprise an optical line terminal OLT and a plurality of optical network units ONU; Described OLT is connected with multiple described ONUs; There are multiple wavelengths for transmitting service information in described TWDM-PON; The method includes: The OLT determines the first ONU and the second ONU, specifically including: determining whether there is the wavelength that can be allocated in the TWDM-PON; In response to determining that the assignable wavelength does not exist in the TWDM-PON, a third ONU is determined corresponding to each of the wavelengths, specifically including: Determine the preset transmission start time of the first ONU; Determine a 4th ONU corresponding to each described wavelength; Described 4th ONU is the described ONU that has been allocated the bandwidth of this wavelength at described preset transmission start time and later; For each of the fourth ONUs, determine whether the fourth ONU has high priority, In response to determining that the fourth ONU has a high priority, the preempted queue is emptied, and the fourth ONU is re-determined, wherein the preempted queue includes at least one described fourth ONU that does not have a high priority, In response to determining that the 4th ONU does not have a high priority, it is further determined whether the transmission end time of the 4th ONU is earlier than the preset transmission end time of the first ONU, In response to determining that the transmission end time of the 4th ONU is earlier than the preset transmission end time of the first ONU, clearing the preempted queue, redetermines the 4th ONU, In response to determining that the transmission end time of the 4th ONU is later than the preset transmission end time of the first ONU, put this 4th ONU into the preempted queue and all the ONUs in the preempted queue Work together as the third ONU; Described the 3rd ONU is the described ONU that satisfies the preset preempted condition; The described 3rd ONU with the earliest transmission start time among the multiple described 3rd ONUs is used as the described 2nd ONU; Described second ONU is the described ONU that is allocated with bandwidth corresponding to any described wavelength; Described first ONU is the described ONU that will seize the bandwidth of described wavelength that described second ONU is allocated; Described The OLT determines the preemption time and the retransmission time; The OLT generates a preemption instruction according to the preemption moment and sends it to the first ONU; the preemption instruction is used to make the first ONU perform service transmission at the preemption moment; The OLT generates a retransmission instruction according to the retransmission moment and sends it to the second ONU; the retransmission instruction is used to make the second ONU perform service transmission at the retransmission moment. 2. The method according to claim 1, wherein the OLT determines a preemption moment and a retransmission moment, specifically comprising: Taking the transmission start time of the second ONU as the preemption time; According to the preemption time, the retransmission time is obtained by calculation. 3. The method according to claim 1, wherein the re-determining the fourth ONU specifically comprises: The next ONU corresponding to the wavelength corresponding to the fourth ONU is used as the re-determined fourth ONU. 4. The method according to claim 2, wherein calculating the retransmission time according to the preemption time comprises: The retransmission time can be calculated by the following formula: t _re = t _pre + t _date + t _guard ; Among them, t _re is the retransmission time, t _pre is the preemption time, t _date is the duration of the first ONU transmission service, and t _guard is the guard interval.

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