CN112087782A

CN112087782A - Bandwidth allocation method for coexistence of EMBB and URLLC in X-Haul network

Info

Publication number: CN112087782A
Application number: CN202010951005.8A
Authority: CN
Inventors: 季晨阳; 毕美华; 吕韵欣; 卢旸; 杨国伟; 周雪芳; 胡淼; 李齐良
Original assignee: Hangzhou Dianzi University
Current assignee: Hangzhou Dianzi University
Priority date: 2020-09-11
Filing date: 2020-09-11
Publication date: 2020-12-15
Anticipated expiration: 2040-09-11
Also published as: CN112087782B

Abstract

The invention discloses a bandwidth allocation method for coexistence of EMBB and URLLC in an X-Haul network, which comprises the following steps: s11, receiving service data needing to be processed; s12, judging whether the received service data is URLLC service, if so, reserving bandwidth for the URLLC service in the current period, and transmitting the URLLC service in Fronthaul and Midhaul; if not, go to step S13; s13, judging whether the received service data is an EMBB service in Frontlaul; if so, calculating the bandwidth allocated to the EMBB service in Fronthaul in the current period and the data volume of each ONU to be allocated, determining a recursion equation according to each ONU to be allocated, and calculating from bottom to top according to the determined recursion equation until reaching the boundary condition to obtain the maximum bandwidth utilized by the current period; if not, go to step S14; s14, judging whether the received service data is an EMBB service in Midhaull, if so, allocating all unallocated bandwidths to the EMBB service in Midhaul in a first-come first-serve mode; and S15, recording the resource allocation condition of the current period, and performing downlink transmission.

Description

Bandwidth allocation method for coexistence of EMBB and URLLC in X-Haul network

Technical Field

The invention relates to the technical field of mobile communication networks, in particular to a bandwidth allocation method for the coexistence of an EMBB and a URLLC in an X-Haul network.

Background

Support for Enhanced Mobile Broadband (EMBB) and Ultra-reliable Low-Latency Communication (URLLC) services will become the mainstream trend in 5G access networks. The EMBB is oriented to a large-bandwidth capacity service with a continuous wide area coverage range, has high requirements on data rate and bandwidth, and can provide 1Gbit/s experience rate and 10Gbit/s peak rate for a user; URLLC services require ultra-low latency and ultra-high reliability, and will provide industrial grade business support that is extremely sensitive to latency and reliability. As the most promising candidate solution, the integration of Passive Optical Network (PON) and Cloud-Radio Access Network (C-RAN) has attracted more and more attention in the industry and academia due to its large capacity and flexible Access capability. In the system, how to meet the low-latency requirements of different scenes and ensure high bandwidth utilization rate is a key problem to be solved urgently.

In the conventional wireless access network system, because the service of the access user has low requirements on bandwidth and time delay, factors which have small influence on transmission reliability and waiting time, such as queuing waiting time, can be ignored. However, in the future 5G and even Beyond 5G systems, due to the diversity of the number and types of services accessed to the network, there is a high requirement on the quality of service provided by the access network, for example, URLLC service is extremely sensitive to delay. In order to effectively solve the service differentiation requirement of an access user in a future mobile communication network, a resource allocation algorithm in an access network system needs to be updated. Among them, to achieve a lower air transmission latency, reducing a Transmission Time Interval (TTI) is an effective method. The 3GPP supports the use of different TTI durations according to user specific requirements, with some smaller scheduling elements, e.g. 0.5ms and 0.143ms (also referred to as mini-slots), in addition to the scheduling elements with a subframe resolution of 1 ms. In terms of meeting bandwidth requirements, the introduction of higher carrier frequencies and massive MIMO technology brings about a substantial increase in transmission data rate. As network demands increase, access networks will face more and more challenges, and currently, relatively single network architectures cannot effectively share transmission resources. For example, Two-stage optimization of uplink forwarding order with cooperative DBA to communication a TDM-PON-based front side link, published by Daisuke Hisano of Journal of Optical Communications and Networking, transmits FH signals in a PON-based fronthaul network system, which has very strict delay requirements, making a large amount of bandwidth unusable. According to the conclusion of the article, the maximum throughput of 10Gbps-PON in the system is only 4.3Gbps, which causes a lot of bandwidth waste and is difficult to meet the challenges brought by the future 5G radio access technology.

Disclosure of Invention

The invention aims to provide a bandwidth allocation method for coexistence of EMBB and URLLC in an X-Haul network aiming at the defects of the prior art, wherein the X-Haul network is utilized to bear Frontaul and Midhaul data, and different bandwidth allocation modes and different scheduling periods are arranged in the face of different service requirements of various services.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for allocating coexisting bandwidth of EMBB and URLLC in an X-Haul network comprises the following steps:

s1, receiving service data needing to be processed;

s2, judging whether the received service data is URLLC service, if so, reserving bandwidth for the URLLC service in the current period, transmitting the URLLC service in the Fronthaul network Fronthaul and the Midhaul by using the reserved bandwidth, and executing a step S5; if not, go to step S3;

s3, judging whether the received service data is an EMBB service in a Fronthaul network Frontaul; if yes, calculating the bandwidth allocated to the EMBB service in the Fronthaul network Frontaul by the current period and the data volume of each optical network unit ONU to be allocated, calculating the maximum bandwidth used by the current period from bottom to top according to the recursion equation determined by each optical network unit ONU to be allocated and the boundary condition according to the determined recursion equation, and executing the step S5; if not, go to step S4;

s4, judging whether the received service data is an EMBB service in the Midhaull network, if so, allocating all unallocated bandwidths to the EMBB service in the Midhaull network in a manner of serving the FCFS first;

and S5, recording the resource allocation condition of the current period, and performing downlink transmission.

Further, the X-Haul network carries Fronthaul and Midhaul data, wherein the low-layer function division point of Fronthaul is selected as option 6, and the high-layer function division point of Midhaul is selected as option 2.

Further, the scheduling period of the URLLC service is 0.143 ms; the scheduling period of the EMBB service is 1 ms.

Further, in step S2, the step of reserving a bandwidth for the URLLC service in the current period is specifically to reserve a bandwidth for each mini-slot included in the current period.

Further, the reserved bandwidth in step S2 is equal to the bandwidth required for transmitting URLLC traffic in the previous cycle.

Further, after the step S2, the transmitting the URLLC service in the Fronthaul network Fronthaul and the Midhaul network by using the reserved bandwidth, the method further includes:

when the reserved bandwidth is not enough to transmit all data arriving at the current mini-slot, the untransmitted data enters the OLT for buffering and is transmitted in the next reserved bandwidth.

Further, in step S3, calculating a bandwidth allocated to the EMBB service in the Fronthaul network frontaul in the current period, specifically:

determining the amount of the bandwidth which can be allocated in the current period and the amount of data which arrives by each optical network unit ONU in the previous period, and calculating the bandwidth which is allocated to the EMBB service in the Fronthaul network Frontaul in the current period, wherein the bandwidth is expressed as:

wherein, B represents the bandwidth amount allocated in the current period; d_FERepresenting the latency requirement of the EMBB traffic in the Fronthaul network frontaul; g represents the time occupied by reserving the bandwidth in each mini-slot; c represents the data rate of the passive optical network PON; b_eIndicating the frame size of the EMBB traffic.

Further, the recursive equation determined in step S3 is expressed as:

when V (i, j) ═ V (i-1, j) indicates that the occupied capacity of the ith ONU is greater than the remaining capacity, the optimal decision result facing the first i ONUs is the same as the optimal decision result facing the first i-1 ONUs; w (i) represents the capacity occupied by the ith ONU; v (i-1, j-w (i)) indicates that the backpack capacity has decreased by w (i) after the ONU is selected.

Further, the step S4 is specifically:

at the beginning of each period, all unallocated bandwidths are allocated to the EMBB traffic in the Midhaul network in a manner of serving the FCFS first, which is expressed as:

wherein B1 represents the amount of unallocated bandwidth; 1 denotes that the total time of the current cycle is 1ms; g represents the time occupied by the reserved bandwidth of each mini-slot; c represents the data rate of the passive optical network PON; b_eIndicating the frame size of the EMBB traffic.

Further, the step S4 further includes:

data which cannot be transmitted in the current period enters a buffer and is transmitted in the allocated bandwidth of the next period until the waiting time exceeds the delay constraint, and the data frame is regarded as violating the delay constraint.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention can support the coexistence of the EMBB service and the URLLC service in the X-Haul network and meet the differentiated delay requirements of different services.

2. The invention can effectively increase multiplexing and improve the utilization rate of system bandwidth.

3. The algorithm principle of the invention is simple and easy to realize.

Drawings

Fig. 1 is a flowchart of a method for allocating bandwidth in coexistence of EMBB and URLLC in an X-Haul network according to an embodiment;

FIG. 2 is a system framework diagram based on the X-Haul architecture according to an embodiment;

fig. 3 is a delay accumulation profile of URLLC traffic provided in one embodiment;

FIG. 4 is a delay accumulation profile for EMBB traffic in Fronthaul according to one embodiment;

fig. 5 is a comparison diagram of bandwidth allocation for EMBB traffic in frontaul by the dynamic programming method (DP), the round-robin scheduling method (RR), and the random scheduling method (RA) according to the first embodiment.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.

The invention aims to provide a bandwidth allocation method for coexistence of EMBB and URLLC in an X-Haul network aiming at the defects of the prior art.

Example one

This embodiment provides a method for allocating bandwidth for coexistence of EMBB and URLLC in an X-Haul network, which utilizes the X-Haul network to carry frontaul and Midhaul, and arranges different bandwidth allocation modes and different scheduling periods in the face of different requirements of various services, as shown in fig. 1, including the steps of:

s11, receiving service data needing to be processed;

s12, judging whether the received service data is URLLC service, if so, reserving bandwidth for the URLLC service in the current period, transmitting the URLLC service in the Fronthaul network Fronthaul and the Midhaul by using the reserved bandwidth, and executing a step S15; if not, go to step S13;

s13, judging whether the received service data is an EMBB service in a Fronthaul network Frontaul; if yes, calculating the bandwidth allocated to the EMBB service in the Fronthaul network Frontaul by the current period and the data volume of each optical network unit ONU to be allocated, calculating the maximum bandwidth used by the current period from bottom to top according to the recursion equation determined by each optical network unit ONU to be allocated and the boundary condition according to the determined recursion equation, and executing the step S15; if not, go to step S14;

s14, judging whether the received service data is an EMBB service in the Midhaull network, if so, allocating all unallocated bandwidths to the EMBB service in the Midhaull network in a manner of serving the FCFS first;

and S15, recording the resource allocation condition of the current period, and performing downlink transmission.

As network demands increase, radio access networks will face more and more challenges, and currently, relatively single network architectures, such as Fronthaul network (frontnaul) and Midhaul network (midheaul), cannot effectively share transmission resources. Therefore, the invention adopts a mixed Fronthaul and Midhaul data transmission network, namely an X-Haul network to transmit the Fronthaul and Midhaul data, thereby achieving the purpose of sharing the transmission network.

As shown in fig. 2. The X-Haul is a novel architecture integrating light and wireless, integrates a fronthaul network and a middle Haul network, and realizes unified management of multi-user differentiated services. The X-Haul network bears Fronthaul and Midhaul data, the low-layer function division point of Fronthaul is selected as option 6, and the Midhaul high-layer function division point is selected as option 2.

However, the frontaul and midheal networks have different requirements for delay, the frontaul network selects a lower layer functional partitioning point for transmitting data between DU and RU, requiring a delay of less than 0.25ms, and the midheal network selects a higher layer functional partitioning point for transmitting data between CU and DU. In addition, the arrival regularity of traffic in frontaul, where traffic arrives at the start of the respective cycle, and midheal, where the arrival time of traffic may be distributed at any point in time within the cycle, is also different from the arrival regularity of traffic in the frontaul and midheal networks. Meanwhile, differentiated services such as EMBB and URLLC generally exist in a 5G network, wherein the URLLC service requires an ultra-low delay of 0.5ms and ultra-high reliability, usually a small data packet of 150 bytes, while the EMBB service has high requirements on data rate and bandwidth, and only requires a delay of 4ms, usually a data packet of 1500 bytes. Thus there are 4 different data flows in the system, namely URLLC traffic in frontaul, EMBB traffic in frontaul, URLLC traffic in midheal, and EMBB traffic in midheal, where the delay requirement of the first three is 0.25ms and the delay requirement of the last one is 3.75 ms. How to handle the differentiation requirements brought by different services in the network becomes a key problem to be solved urgently. Therefore, the embodiment provides a bandwidth allocation algorithm for the coexistence of the EMBB and the URLLC in the X-Haul network, so as to support the coexistence of multiple services in the future network.

In step S12, it is determined whether the received service data is a URLLC service, if so, bandwidth is reserved for the URLLC service in the current period, and the URLLC services in the Fronthaul network Fronthaul and the Midhaul network Midhaul are transmitted using the reserved bandwidth, and step S15 is executed; if not, step S13 is executed.

When the judged service data is the URLLC service, reserving a part of bandwidth in each mini-slot contained in the current period at the starting moment of each period for transmitting the URLLC services in Fronthaul and Midhaul, and ensuring the low delay of the URLLC service.

The method specifically comprises the following steps: URLLC service data arrives according to a 0.143ms period, and the delay constraint is 0.25ms, wherein URLLC service in Frontaul arrives at the beginning of each period, and URLLC service in Midhaul arrives according to Poisson in each period. And reserving a part of bandwidth in each mini-slot contained in the current period at the starting moment of each period, wherein the size of the reserved bandwidth is preset in an optical network unit OLT. The reserved bandwidth is equal to the bandwidth required for transmitting URLLC traffic in the last period and is evenly distributed into each mini-slot. When the URLLC service arrives at each mini-slot, the URLLC service can be transmitted by reserved bandwidth, and when the reserved bandwidth is not enough to transmit all data arriving at the current mini-slot, the untransmitted data enters an optical network unit (OLT) for caching and is transmitted in the next reserved bandwidth, and the URLLC service has higher priority. And after each mini-slot is finished, recording the actual arrival data volume of the current period for predicting the reserved bandwidth of the next period.

In step S13, it is determined whether the received service data is an EMBB service in the Fronthaul network frontaul; if yes, calculating the bandwidth allocated to the EMBB service in the Fronthaul network Frontaul by the current period and the data volume of each optical network unit ONU to be allocated, calculating the maximum bandwidth used by the current period from bottom to top according to the recursion equation determined by each optical network unit ONU to be allocated and the boundary condition according to the determined recursion equation, and executing the step S15; if not, step S14 is executed.

When the judged service data is the EMBB service in the Fronthaul network Frontaul, at the starting time of each period, the unallocated bandwidth meeting the EMBB service delay constraint in Frontaul is allocated to the EMBB service in Frontaul according to a dynamic programming method. And dynamic planning firstly determines the amount of the allocable bandwidth and the data volume of each ONU to be allocated, secondly determines a recursion equation, and finally calculates from bottom to top according to the recursion equation to the boundary condition to obtain the maximum bandwidth available in the current period.

The method specifically comprises the following steps: unallocated bandwidth within the delay requirement is allocated as much as possible to EMBB traffic in frontaul. The latency requirement for the EMBB traffic in frontaul is 0.25ms and the allocated bandwidth is the reserved bandwidth in the first two mini-slots of the period. The system records the number of EMBB frames in Fronthaul of all N ONU arriving in the previous period, and selects proper ONU data according to the number of the arriving frames of each ONU, so that the bandwidth utilization rate required by delay is maximized. This bandwidth allocation problem can therefore be treated as a 0-1 knapsack problem, solved by dynamic programming.

Firstly, determining the allocable bandwidth amount of the current period and the data amount of each ONU in the previous period. The allocable bandwidth amount of the current period can be represented by the number B of EMBB frames in transmittable Frontaul, and the calculation method is as follows:

wherein, B represents the bandwidth amount allocated in the current period; d_FERepresenting the latency requirement of the EMBB traffic in the Fronthaul network frontaul; g represents the time occupied by reserving the bandwidth in each mini-slot in the step S12; c represents the data rate of the passive optical network PON; b_eIndicating the frame size of the EMBB traffic.

Second, dynamic planning requires finding recursion relationships. There are two possibilities for data facing the ith ONU: one is that the system capacity is less than the ONU frame number, the ONU cannot be selected. The value of the used capacity at this time is the same as that of i-1 ONU, i.e. V (i, j) ═ V (i-1, j), where V (i, j) represents the optimal decision result for the first i ONUs when the used capacity is j. Another possibility is that there is enough capacity to select the ONU, but the selection does not necessarily reach the current optimal value, so it needs to be decided whether to select the ONU or not according to the values of both solutions. The recursion equation is as follows:

And finally, calculating from bottom to top according to a recursive equation until a boundary condition is reached, namely the maximum value of the decisions of all N ONUs which can be sent when the capacity is B, and finishing the iteration. The output result V (N, B) is the maximum transmission capacity that can be currently utilized, thereby maximizing the throughput of the EMBB traffic in frontaul.

In step S14, it is determined whether the received service data is an EMBB service in the midstream network midheall, and if so, all unallocated bandwidths are allocated to the EMBB service in the midstream network midheall in a manner of serving the FCFS first.

When the judged service data is the EMBB service in the Midhaull network, all the unallocated bandwidths are allocated to the EMBB service in the Midhaul network in a first-come first-serve mode at the starting moment of each period, and the bandwidths are fully utilized.

The method specifically comprises the following steps: at the beginning of each cycle, all unallocated bandwidth is allocated to EMBB traffic in Midhaul in a First Come First Served (FCFS) manner. The allocated bandwidth is the reserved bandwidth in all mini-slots of the period, and the B-frame bandwidth allocated for the EMBB service in frontaul in step S13.

Therefore, the unallocated bandwidth in the period can be represented by the number of EMBB frames B1 in the transmittable Midhaul, and the calculation method is as follows:

wherein B1 represents the amount of unallocated bandwidth; 1 represents that the total time of the current period is 1 ms; g represents the reserved bandwidth occupation of each mini-slot in step S12The time of (d); c represents the data rate of the passive optical network PON; b_eRepresents the frame size of the EMBB service; b represents the number of frames that have been allocated to the EMBB in Fronthaul in step S12.

The delay requirement for the EMBB traffic in Midhaul is 3.75 ms. Data which can not be transmitted in the current period enters a buffer and is transmitted in the distribution bandwidth of the next period until the waiting time exceeds the delay constraint, and the data frame is regarded as violating the delay constraint.

As shown in fig. 3 and fig. 4, it can be seen that the delay accumulation distribution function graph of the URLLC service and the EMBB service obtained by the bandwidth allocation method for coexistence of the EMBB and the URLLC in the X-Haul network can maintain the delay of various services within the delay constraint. Fig. 5 is a comparison graph of the effect of the dynamic programming method (DP) and the polling method (RR) and the random scheduling (RA), and it can be seen that the dynamic programming method can increase the bandwidth of the EMBB service in frontaul by about 15%.

In summary, the method for allocating the bandwidth with the coexistence of the EMBB and the URLLC in the X-Haul network according to the present embodiment can support the coexistence of the EMBB service and the URLLC service in the X-Haul network, meet the delay requirements of different services, and improve the bandwidth utilization of the system. Therefore, the algorithm of the embodiment can be better applied to the X-Haul network with the coexistence of the EMBB and the URLLC.

Compared with the prior art, the embodiment has the following beneficial effects:

1. the method can support the coexistence of the EMBB service and the URLLC service in the X-Haul network, and meet the differentiated delay requirements of different services.

2. Multiplexing can be effectively increased, and the utilization rate of system bandwidth is improved.

3. The algorithm principle is simple and easy to realize.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for allocating coexisting bandwidth of EMBB and URLLC in an X-Haul network is characterized by comprising the following steps:

s1, receiving service data needing to be processed;

2. The method as claimed in claim 1, wherein the X-Haul network carries frontaul and midheal data, wherein the low-layer functional partition point of frontaul is selected as option 6, and the high-layer functional partition point of midheal is selected as option 2.

3. The method of claim 1, wherein the scheduling period of said URLLC service is 0.143 ms; the scheduling period of the EMBB service is 1 ms.

4. The method of claim 1, wherein in step S2, the bandwidth is reserved for the URLLC service in the current period, specifically, the bandwidth is reserved in each mini-slot included in the current period.

5. The method of claim 4, wherein the reserved bandwidth in step S2 is equal to the bandwidth required for transmitting URLLC traffic in the previous period.

6. The method as claimed in claim 5, wherein the step S2 further includes, after the step of transmitting the URLLC traffic in Fronthaul network Fronthaul and Midhaul network using the reserved bandwidth in step S2:

7. The method for allocating the coexisting bandwidth of the EMBB and the URLLC in the X-Haul network as claimed in claim 4, wherein the step S3 is performed to calculate the bandwidth allocated to the EMBB service in the Fronthaul network Frontaul in the current period, specifically:

wherein, B represents the bandwidth amount allocated in the current period;D_FErepresenting the latency requirement of the EMBB traffic in the Fronthaul network frontaul; g represents the time occupied by reserving the bandwidth in each mini-slot; c represents the data rate of the passive optical network PON; b_eIndicating the frame size of the EMBB traffic.

8. The method of claim 7, wherein the recursive equation determined in step S3 is expressed as:

9. The method for allocating the coexisting bandwidth of the EMBB and the URLLC in the X-Haul network as claimed in claim 8, wherein said step S4 specifically comprises:

wherein B1 represents the amount of unallocated bandwidth; 1 represents that the total time of the current period is 1 ms; g represents the time occupied by the reserved bandwidth of each mini-slot; c represents the data rate of the passive optical network PON; b_eIndicating the frame size of the EMBB traffic.

10. The method for allocating the bandwidth of the coexistence of the EMBB and the URLLC in the X-Haul network as claimed in claim 9, wherein said step S4 further includes: