WO2025048689A1

WO2025048689A1 - Scheduling ran data

Info

Publication number: WO2025048689A1
Application number: PCT/SE2023/050865
Authority: WO
Inventors: Mats Forsman; Tomas Thyni; Tobias Lindquist; Peter ERLANDSSON
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2023-08-31
Filing date: 2023-08-31
Publication date: 2025-03-06
Anticipated expiration: 2026-02-28

Abstract

The present disclosure relates to scheduling of radio access network (RAN) data traffic to be transported in a communication network. In an aspect, a method of a RAN scheduler (18) is provided of scheduling RAN data traffic to be transported in a communication network (10). The method comprises receiving (S102), from a fronthaul device (17), an indication of impending fronthaul congestion associated with at least one fronthaul data traffic flow, and adapting (S103) scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

Description

SCHEDULING RAN DATA

TECHNICAL FIELD

[0001] The present disclosure relates to a method of a radio access network (RAN) scheduler of scheduling RAN data traffic to be transported in a communication network, and a RAN scheduler performing the method. The present disclosure further relates to a method of a fronthaul device of facilitating scheduling of RAN data to be communicated in the communication network, and a fronthaul device performing the method.

BACKGROUND

[0002] Currently in communication networks, a problem experienced by RAN schedulers in planning and scheduling resources to be assigned to a RAN is that the RAN schedulers do not know whether errors such as dropped packets, increased latency, limited bitrate, etc., are a result of air interface problems in the RAN or fronthaul transport problems, such as congestion in the fronthaul.

[0003] Fronthaul traffic is typically performed in bursts with high peak bitrates and can therefore cause short congestion situations. Packet drops in the fronthaul will typically be interpreted by the RAN scheduler as a RAN-related problem and actions taken by the RAN scheduler to mitigate these problems may in fact result in even worse congestion. Thus, a few highly loaded wireless communication devices may cause overload in the fronthaul and thereby congestion to all wireless communication devices connected to the same fronthaul network via a radio unit serving the RAN. Network operators commonly resolve this by over-dimensioning the fronthaul transport, which is expensive and thus undesired.

SUMMARY

[0004] One objective is to solve this problem in the art and thus to provide an improved method of scheduling RAN data traffic to be transported in a communication network in order to avoid, or at least mitigate, impending fronthaul congestion. [0005] This objective is attained in a first aspect by a method of a RAN scheduler of scheduling RAN data traffic to be transported in a communication network. The method comprises receiving, from a fronthaul device, an indication of impending fronthaul congestion associated with at least one fronthaul data traffic flow, and adapting scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

[0006] This objective is attained in a second aspect by a RAN scheduler configured to schedule RAN data traffic to be transported in a communication network. The RAN scheduler comprises a processing unit and a memory, said memory containing instructions executable by said processing unit, whereby the RAN scheduler is operative to receive, from a fronthaul device, an indication of impending fronthaul congestion associated with at least one fronthaul data traffic flow, and to adapt scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

[0007] This objective is attained in a third aspect by a method of a fronthaul device of facilitating scheduling of RAN data to be communicated in a communication network. The method comprises detecting an impending fronthaul congestion associated with at least one fronthaul data traffic flow, and sending, to a RAN scheduler, an indication of the impending fronthaul congestion associated with the at least one fronthaul data traffic flow, wherein the RAN scheduler performs adapting of the scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

[0008] This objective is attained in a fourth aspect by a fronthaul device configured to facilitate scheduling of RAN data to be communicated in a communication network. The fronthaul device comprises a processing unit and a memory, said memory containing instructions executable by said processing unit, whereby the fronthaul device is operative to detect an impending fronthaul congestion associated with at least one fronthaul data traffic flow, and to send, to a RAN scheduler, an indication of the impending fronthaul congestion associated with the at least one fronthaul data traffic flow, wherein the RAN scheduler performs adapting of the scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

[0009] With the proposed aspects, rather than the RAN scheduler having to adapt to an error occurring in the fronthaul and/or the RAN without knowing for certain the reason for the error, the RAN scheduler is advantageously informed of an impending fronthaul congestion detected by the fronthaul device in uplink or downlink, and may thus adapt RAN traffic scheduling accordingly to mitigate or even avoid the impending fronthaul congestion situation.

[0010] In an embodiment, in case the impending fronthaul congestion is indicated to occur in uplink, the method comprises sending, to a wireless communication device in the RAN associated with said at least one fronthaul data traffic flow, via the fronthaul device and a radio unit serving the RAN, the adapting of the scheduling of the RAN data traffic to be performed in uplink.

[0011] In an embodiment, in case the impending congestion is indicated to occur in downlink, the receiving comprises receiving, from the fronthaul device, the indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow, the fronthaul device previously having sent said indication to the radio unit serving the RAN, and in response thereto received said indication from the radio unit and forwarded said indication to the RAN scheduler.

[0012] In an embodiment, the indication of the impending congestion is configured to be included by the fronthaul device in an Explicit Congestion Notification (ECN) field of an Internet Protocol (IP) header associated with the at least one fronthaul data traffic flow.

[0013] In a fifth aspect, a computer program is provided comprising computerexecutable instructions for causing a RAN scheduler of the second aspect to perform steps recited in the method of the first aspect when the computer-executable instructions are executed on a processing unit included in the RAN scheduler.

[0014] In a sixth aspect a computer program product is provided comprising a computer readable medium, the computer readable medium having the computer program according to the fifth aspect embodied thereon. [0015] In a seventh aspect, a computer program is provided comprising computer-executable instructions for causing a fronthaul device of the fourth aspect to perform steps recited in the method of the third aspect when the computerexecutable instructions are executed on a processing unit included in the fronthaul device.

[0016] In an eighth aspect, a computer program product is provided comprising a computer readable medium, the computer readable medium having the computer program according to the seventh aspect embodied thereon.

[0017] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Aspects and embodiments are now described, by way of example, with reference to the accompanying drawings, in which:

[0019] Figure 1 illustrates a communication network in which embodiments may be implemented;

[0020] Figure 2 shows a signalling diagram illustrating a method according to an embodiment;

[0021] Figure 3 shows a signalling diagram illustrating a method according to a further embodiment;

[0022] Figure 4 shows a signalling diagram illustrating a method according to still a further embodiment;

[0023] Figure 5 illustrates a RAN scheduler according to an embodiment; and

[0024] Figure 6 illustrates a fronthaul device according to an embodiment. DETAILED DESCRIPTION

[0025] The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown.

[0026] These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully convey the scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0027] Reference will be made to the illustration of network 10 of Figure 1 in which embodiments may be implemented and the signalling diagram of Figure 2 for describing an embodiment of a method of a radio access network (RAN) controller of scheduling data transported in the network 10.

[0028] As shown in the illustration of the network 10 of Figure 1, a plurality of wireless communication devices 11-13 are served by a radio unit (RU) 14 in a radio access network (RAN) 15. While Figure 1 for brevity only illustrates three wireless communication devices 11-13, the RU 14 may in practice serve hundreds or thousands of wireless communication devices in the RAN 15. Further, multiple RUs may be employed to serve the RAN 15. The wireless communication devices are commonly referred to as User Equipment (UE) and may be embodied in the form smart phones, tablets, connected vehicles, etc.

[0029] The RU 14 is connected to a fronthaul 16 comprising fronthaul devices 17 such as e.g. s Packet Fronthaul Switch Routers (SWRs). The fronthaul 16 acts as an intermediate link between the RAN 15 and a RAN scheduler 18. The RAN scheduler 18 forms part of a baseband (BB) processing device 19 configured to manage radio functions in the network 10. The fronthaul 16 typically comprises fibers carrying packet data complying with an evolved Common Public Radio Interface (eCPRI) standard. Similar to the RU 14 serving the RAN 15, the fronthaul 16 may transport hundreds or even thousands of data traffic flows passing to/from the UEs of the RAN 15 in downlink/uplink via the RU 14.

[0030] The RAN scheduler 18 plans and assigns resources to be granted to the RAN 15 for the UEs 11-13 to be able to communicate, such as e.g. communication frequencies to be used, bandwidth to be the assigned to individual UEs, retransmission of lost data packets, handover of UEs to neighbouring RBSs, etc.

[0031] The BB processing device 19 (and thus the RAN scheduler 18) functionally forms part of a radio base station utilizing the RU 14 to serve the UEs 11-13 in the RAN 15.

[0032] Now, in the art, a problem experienced by the RAN scheduler 18 in planning and scheduling resources to be assigned to the RAN 15 is that the RAN scheduler 18 does not know whether errors such as dropped packets, increased latency, limited bitrate, etc., are a result of air interface problems in the RAN 15 or fronthaul transport problems, such as congestion in the fronthaul 16.

[0033] Since the BB processing device 19 functionally is a part of the radio base station utilizing the RU 14 to serve the RAN 15, the BB processing device 19 and the RAN scheduler 18 are typically made aware of any impending congestion in the RAN 15. However, the BB processing device 19 and the RAN scheduler 18 are unaware of any congestion occurring in the fronthaul 16.

[0034] Fronthaul traffic is typically performed in bursts with high peak bitrates and can therefore cause short congestion situations. Packet drops or delayed packets in the fronthaul 16 will typically be interpreted by the RAN scheduler 18 as a RAN air interface-related problem and actions taken by the RAN scheduler 18 to mitigate these problems may in fact result in even worse congestion, e.g. through addition of further error protection in the RAN traffic flow. Thus, a few (or even a single) highly loaded UEs 11-13 may cause overload in the fronthaul 16 and thereby congestion to all UEs 11-13 connected via the RU 14 to the same fronthaul network 16. Network operators commonly resolve this by over-dimensioning the fronthaul transport, which is expensive.

[0035] Figure 2 shows a signalling diagram illustrating a method of resolving this issue in an embodiment.

[0036] In step S101, the fronthaul device 17 detects an impending congestion for at least one fronthaul data traffic flow transported over the fronthaul 16. For instance, the first UE 11 is scheduled to perform a communication session which will require great bandwidth resources to be assigned to the first UE 11, thereby potentially causing congestion in the fronthaul 16. [0037] As is understood, numerous data traffic flows are transported via the fronthaul 16, both in uplink (UL) and downlink (DL).

[0038] Thereafter, in step S102, the fronthaul device 17 indicates the impending congestion in the fronthaul 16 to the RAN scheduler 18. Thus, the RAN scheduler 18 is informed that there is an impending congestion for at least one fronthaul data traffic flow, in this example for a fronthaul data traffic flow associated with the first UE 11.

[0039] Upon acquiring the indication from the fronthaul device 17 in S102 that there is an impending fronthaul congestion, the RAN scheduler 18 adapts in S103 the RAN scheduling to resolve, or at least mitigate, the impending congestion in the fronthaul 16.

[0040] For example, the RAN scheduler 18 may determine that less bandwidth resources are to be assigned to the first UE 11 being associated with the fronthaul data traffic flow for which the impending congestion is detected, which typically would result in a lower bit-rate of the first UE 11 at the expense of a lesser risk of fronthaul congestion occurring. In another example, the first UE 11 is moved to a neighbouring cell being capable of providing the required bandwidth without congestion occurring. In yet an example, the first UE 11 is assigned other times slots in which to perform the communication (as compared to the other UEs 12, 13) in order to avoid the impending fronthaul congestion. As is understood, there are in practice numerous scheduling adaptions that advantageously may be undertaken by the RAN scheduler 18 to mitigate or even avoid the impending fronthaul congestion.

[0041] Now, depending on whether the fronthaul congestion is impending in UL or DL, a slightly different approach is taken by the RAN scheduler 18, as will be discussed in the following.

[0042] Figure 3 shows a signalling diagram illustrating an embodiment of a method of the RAN controller of scheduling data to be transported in UL of the fronthaul 16.

[0043] In step S101, the fronthaul device 17 detects an impending UL congestion for at least one fronthaul data traffic flow. In an example, the fronthaul device 17 may detect that the first UE 11 is scheduled to perform a communication session which will require bandwidth resources of, say, 10 MB to be assigned to the first UE 11, but that a fronthaul congestion will occur already at 6 MB being transported by the first UE 11 in UL via the fronthaul 16.

[0044] Thus, in step S102, the fronthaul device 17 indicates the impending UL congestion in the fronthaul 16 to the RAN scheduler 18 by sending a UL message accordingly. Thus, the RAN scheduler 18 is informed that there is an impending UL congestion for at least one fronthaul data traffic flow, in this example for a fronthaul data traffic flow associated with the first UE 11.

[0045] For instance, a packet of the fronthaul data traffic flow for which the impending UL congestion is detected may be configured to comprise one or more bits utilized by the fronthaul device 17 to indicate the impending UL congestion.

[0046] Upon acquiring the indication from the fronthaul device 17 in S102 that there is an impending fronthaul congestion on the UL, the RAN scheduler 18 adapts in S103 the scheduling of the RAN data traffic to resolve, or at least mitigate, the impending congestion in the fronthaul 16.

[0047] In this particular example, the RAN scheduler 18 adapts the RAN scheduling by decreasing the bandwidth resources being assigned to the first UE 11 in S103. Thus, rather than assigning 10 MB to the UL data transport via the fronthaul 16, bandwidth is limited to 6 MB.

[0048] After having appropriately adapted the scheduling of RAN data traffic in S103, the RAN scheduler 18 provides the first UE 11 in step S104 (illustrated by the dashed arrows) via the fronthaul device 17 and the RU 14 with the adapting of the scheduling of the RAN data traffic to be performed, i.e. that 6 MB will be assigned to the first UE 11 for the RAN data traffic to be transported in UL to avoid the impending congestion in the fronthaul in instead of 10 MB.

[0049] Thus, the RAN schedular 18 specifies in step S103 that adaption of the RAN data traffic scheduling is to be performed to avoid any impending fronthaul congestion in UL. The adapted RAN data traffic scheduling is thus sent in step S104 via the fronthaul device 17 of the fronthaul 16 to the RU 14 and further to the first UE 11 which is associated with the fronthaul data traffic flow for which the impending UL congestion is detected initial is detected by the fronthaul device 17 in S101. As is understood, the fronthaul device 17 will just forward the adapted UL RAN data traffic scheduling received from the RAN scheduler 18 to the RU 14. [0050] The first UE n will thus advantageously be assigned 6 MB (rather than 10 MB) for the RAN traffic data to be transported via the fronthaul 16 in UL in order to avoid fronthaul congestion.

[0051] Figure 4 shows a signalling diagram illustrating an embodiment of a method of the RAN controller of scheduling data to be transported in DL of the fronthaul 16.

[0052] In step S101, the fronthaul device 17 detects an impending DL congestion for at least one fronthaul data traffic flow. Again, the fronthaul device 17 may detect that the first UE 11 is scheduled to perform a communication session which will require bandwidth resources of, say, 10 MB to be assigned to the first UE 11, but that a fronthaul congestion will occur already at 6 MB being transported by the first UE 11 in DL via the fronthaul 16.

[0053] Thus, in step SiO2a, the fronthaul device 17 indicates the impending DL congestion in the fronthaul 16 to the RU 14 by sending a DL message accordingly. Thus, the RU 14 is informed that there is an impending DL congestion for at least one fronthaul data traffic flow, in this example for a fronthaul data traffic flow associated with the first UE 11.

[0054] For instance, a packet of the fronthaul data traffic flow for which the impending DL congestion is detected may be configured to comprise a one or more bits utilized by the fronthaul device 17 to indicate the impending DL congestion.

[0055] Upon acquiring the indication from the fronthaul device 17 in SiO2a that there is an impending fronthaul congestion on the DL, the RU 14 returns the indication in UL in SiO2b to the fronthaul device 17, which in its turn indicates the impending DL congestion in the fronthaul 16 to the RAN scheduler 18 by forwarding the indication of the impending DL fronthaul congestion received from the RU 14 in SiO2b.

[0056] Finally in step S103, the RAN scheduler 18 adapts in S103 the scheduling of the RAN data traffic to resolve, or at least mitigate, the impending congestion in the fronthaul 16 by scheduling resources for the RAN traffic data assigned to the first UE 11 in the DL to be limited to 6 MB rather than 10 MB. Thus, rather than the BB processing device 19 sending 10 MB of data to the first UE 11 in the RAN 11 via the fronthaul 16 and the RU 14, 6 MB of data till be sent. [0057] With the embodiments of Figures 2-4, rather than the RAN scheduler 18 having to adapt to an error occurring in the fronthaul 16 and/or the RAN 15 without knowing for certain the reason for the error, the RAN scheduler 18 is advantageously informed of an impending fronthaul congestion detected by the fronthaul device 17 in UL or DL, and may thus adapt RAN traffic scheduling accordingly to mitigate or even avoid the impending fronthaul congestion situation.

[0058] In practice, the indication of the impending congestion may in an embodiment be included by the fronthaul device 17 in a so-called Explicit Congestion Notification (ECN) field of an Internet Protocol (IP) header associated with the at least one fronthaul data traffic flow for which the impending congestion is detected. The usage of ECN is described in much detail in IETF RFC 3168 (“Internet Engineering Task Force Request for Comments 3168”). Advantageously, if the already available ECN field is used to indicate the impending congestion, there is no need to introduce a new data field or information element (IE) to signal the impending congestion to the RAN scheduler 18, even if such approach alternatively may be envisaged.

[0059] Figure 5 illustrates a RAN scheduler 18 configured to schedule RAN data traffic to be transported in a communication network according to an embodiment, where the steps of the method performed by the RAN scheduler 18 in practice are performed by a processing unit 111 embodied in the form of one or more microprocessors arranged to execute a computer program 112 downloaded to a storage medium 113 associated with the microprocessor, such as a Random Access Memory (RAM), a Flash memory or a hard disk drive. The processing unit 111 is arranged to cause the RAN scheduler 18 to carry out the method according to embodiments when the appropriate computer program 112 comprising computerexecutable instructions is downloaded to the storage medium 113 and executed by the processing unit 111. The storage medium 113 may also be a computer program product comprising the computer program 112. Alternatively, the computer program 112 may be transferred to the storage medium 113 by means of a suitable computer program product, such as a Digital Versatile Disc (DVD) or a memory stick. As a further alternative, the computer program 112 may be downloaded to the storage medium 113 over a network. The processing unit 111 may alternatively be embodied in the form of a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), etc. The RAN scheduler 18 further comprises a communication interface 114 (wired and/or wireless) over which the RAN scheduler 18 is configured to transmit and receive data.

[0060] Figure 6 illustrates a fronthaul device 17 configured to facilitate scheduling of RAN data to be communicated in a communication network according to an embodiment, where the steps of the method performed by the fronthaul device 17 in practice are performed by a processing unit 211 embodied in the form of one or more microprocessors arranged to execute a computer program 212 downloaded to a storage medium 213 associated with the microprocessor, such as a RAM, a Flash memory or a hard disk drive. The processing unit 211 is arranged to cause the fronthaul device 17 to carry out the method according to embodiments when the appropriate computer program 212 comprising computer-executable instructions is downloaded to the storage medium 213 and executed by the processing unit 211. The storage medium 213 may also be a computer program product comprising the computer program 212. Alternatively, the computer program 212 may be transferred to the storage medium 213 by means of a suitable computer program product, such as a DVD or a memory stick. As a further alternative, the computer program 212 may be downloaded to the storage medium 213 over a network. The processing unit 211 may alternatively be embodied in the form of a DSP, an ASIC, an FPGA, a CPLD, etc. The fronthaul device 17 further comprises a communication interface 214 (wired and/or wireless) over which the fronthaul device 17 is configured to transmit and receive data.

[0061] In the examples, the network 10 includes a radio access network (RAN) 15. The radio access network (RAN) 15 includes one or more radio access network nodes, such as such as Radio Units (RU) 14, baseband (BB) processing device 19 or any other similar 3^rd Generation Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the network 10 includes one or more Open-RAN (ORAN) network nodes 14, 19. An ORAN network node is a node in the network 10 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the network 10.

[0062] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU) for baseband processing, an open central unit (O- CU), including an O-CU control plane (O-CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non- real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification or comparable technologies). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wi, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN network node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 11-13 to the network 10 over one or more wireless connections.

[0063] The aspects of the present disclosure have mainly been described above with reference to a few embodiments and examples thereof. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.

[0064] Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

1. A method of a radio access network, RAN, scheduler (18) of scheduling RAN data traffic to be transported in a communication network (10), comprising: receiving (S102), from a fronthaul device (17), an indication of impending fronthaul congestion associated with at least one fronthaul data traffic flow; and adapting (S103) scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

2. The method of claim 1, wherein in case the impending fronthaul congestion is indicated to occur in uplink, the method comprises: sending (S104), to a wireless communication device (11) in the RAN (15) associated with said at least one fronthaul data traffic flow, via the fronthaul device (17) and a radio unit (14) serving the RAN (15), the adapting of the scheduling of the RAN data traffic to be performed in uplink.

3. The method of claim 1, wherein in case the impending congestion is indicated to occur in downlink, the receiving (S102) comprises: receiving (SiO2c), from the fronthaul device (17), the indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow, the fronthaul device (17) previously having sent (SiO2a) said indication to the radio unit (14) serving the RAN (15), and in response thereto received (SiO2b) said indication from the radio unit (14) and forwarded said indication to the RAN scheduler (18).

4. The method of any one of the preceding claims, wherein the indication of the impending congestion is configured to be included by the fronthaul device (17) in an Explicit Congestion Notification, ECN, field of an Internet Protocol, IP, header associated with the at least one fronthaul data traffic flow.

5. A method of a fronthaul device (17) of facilitating scheduling of radio access network, RAN, data to be communicated in a communication network (10), comprising: detecting (S101) an impending fronthaul congestion associated with at least one fronthaul data traffic flow; sending (S102), to a RAN scheduler (18), an indication of the impending fronthaul congestion associated with the at least one fronthaul data traffic flow, wherein the RAN scheduler (18) performs adapting (S103) of the scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

6. The method of claim 5, wherein in case the impending fronthaul congestion is indicated to occur in uplink, the method comprises: receiving (S104), from the RAN scheduler (18), the adapting of the scheduling of the RAN data traffic to be performed in uplink and forwarding said adapting of the scheduling of the RAN data traffic to be performed via the radio unit (14) to a wireless communication device (11) in the RAN (15) associated with said at least one fronthaul data traffic flow.

7. The method of claim 5, wherein in case the impending fronthaul congestion is indicated to occur in downlink, the method comprises: sending (SiO2a), to a radio unit (14) serving the RAN (15), the indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow; receiving (102b), from the radio unit (14) in response to the sent indication, the indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow; and forwarding (102c), to the RAN scheduler (18), said indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow.

8. The method of any one of claims 5-7, wherein the indication of the impending congestion is configured to be included by the fronthaul device (17) in an Explicit Congestion Notification, ECN, field of an Internet Protocol, IP, header associated with the at least one fronthaul data traffic flow.

9. A computer program (112) comprising computer-executable instructions for causing a RAN scheduler (18) to perform steps recited in any one of claims 1-4 when the computer-executable instructions are executed on a processing unit (111) included in the RAN scheduler (18).

10. A computer program product comprising a computer readable medium (113), the computer readable medium having the computer program (112) according to claim 9 embodied thereon.

11. A computer program (212) comprising computer-executable instructions for causing a fronthaul device (17) to perform steps recited in any one of claims 5-8 when the computer-executable instructions are executed on a processing unit (211) included in the fronthaul device (17).

12. A computer program product comprising a computer readable medium (213), the computer readable medium having the computer program (212) according to claim 11 embodied thereon.

13. A radio access network, RAN, scheduler (18) configured to schedule RAN data traffic to be transported in a communication network (10), the RAN scheduler (18) comprising a processing unit (111) and a memory (113), said memory containing instructions (112) executable by said processing unit (111), whereby the RAN scheduler (18) is operative to: receive, from a fronthaul device (17), an indication of impending fronthaul congestion associated with at least one fronthaul data traffic flow; and adapt scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

14. The RAN scheduler (18) of claim 13, further being operative to, in case the impending fronthaul congestion is indicated to occur in uplink: send, to a wireless communication device (11) in the RAN (15) associated with said at least one fronthaul data traffic flow, via the fronthaul device (17) and a radio unit (14) serving the RAN (15), the adapting of the scheduling of the RAN data traffic to be performed in uplink.

15. The RAN scheduler (18) of claim 14, being operative to, in case the impending congestion is indicated to occur in downlink: receive, from the fronthaul device (17), the indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow, the fronthaul device (17) previously having sent said indication to the radio unit (14) serving the RAN (15), and in response thereto received said indication from the radio unit (14) and forwarded said indication to the RAN scheduler (18).

16. The RAN scheduler (18) of any one of claims 13-15, wherein the indication of the impending congestion is configured to be included by the fronthaul device (17) in an Explicit Congestion Notification, ECN, field of an Internet Protocol, IP, header associated with the at least one fronthaul data traffic flow.

17. A fronthaul device (17) configured to facilitate scheduling of radio access network, RAN, data to be communicated in a communication network (10), the fronthaul device (17) comprising a processing unit (211) and a memory (213), said memory containing instructions (212) executable by said processing unit (211), whereby the fronthaul device (17) is operative to: detect an impending fronthaul congestion associated with at least one fronthaul data traffic flow; send, to a RAN scheduler (18), an indication of the impending fronthaul congestion associated with the at least one fronthaul data traffic flow, wherein the RAN scheduler (18) performs adapting (S103) of the scheduling of RAN data traffic based on the acquired indication, the adapted scheduling being performed to mitigate the indicated impending fronthaul congestion associated with the at least one fronthaul data traffic flow.

18. The fronthaul device (17) of claim 17, further being operative to, in case the impending fronthaul congestion is indicated to occur in uplink: receive, from the RAN scheduler (18), the adapting of the scheduling of the RAN data traffic to be performed in uplink and forwarding said adapting of the scheduling of the RAN data traffic to be performed via the radio unit (14) to a wireless communication device (11) in the RAN (15) associated with said at least one fronthaul data traffic flow.

19. The fronthaul device (17) of claim 17, further being operative to, in case the impending fronthaul congestion is indicated to occur in downlink: send, to a radio unit (14) serving the RAN (15), the indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow; receive, from the radio unit (14) in response to the sent indication, the indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow; and forward, to the RAN scheduler (18), said indication of impending downlink fronthaul congestion associated with at least one fronthaul data traffic flow.

20. The fronthaul device (17) of any one of claims 17-19, wherein the indication of the impending congestion is configured to be included by the fronthaul device (17) in an Explicit Congestion Notification, ECN, field of an Internet Protocol, IP, header associated with the at least one fronthaul data traffic flow.