Method, apparatus and computer program

Abstract

An apparatus measuring traffic associated with a radio unit RU. A first mode of the radio unit is determined based on the measured traffic and a traffic capacity associated with the mode S804. The rad

Description

Field The present application relates to a method, apparatus, and computer program for a wireless communication system. Background A communication system may be a facility that enables communication sessions between two or more entities such as user terminals, base stations / access points and / or other nodes by providing carriers between the various entities involved in the communications path. A communication system may be provided, for example, by means of a communication network and one or more compatible communication devices. The communication sessions may comprise, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and / or content data and so on. Non-limiting examples of services provided comprise two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet. Summary According to an aspect, there is provided an apparatus comprising: means for determining traffic associated with a radio unit; means for determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes; and means for providing, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode. In an example, the traffic capacity of the radio unit associated with each mode of the plurality of modes is related to a power usage of the radio unit. In an example, the first mode is associated with a different traffic capacity and power usage than the second mode. In an example, a lower traffic capacity corresponds to a lower power usage, and vice-versa. In an example, the means for determining traffic associated with a radio unit comprises at least one of the following: means for detecting traffic associated with the radio unit, means for measuring traffic associated with the radio unit, means for estimating traffic associated with the radio unit, or means for predicting traffic associated with the radio unit. In an example, the apparatus comprises: means for receiving information related to each of the plurality of modes, wherein the information for each of the plurality of modes comprises at least one of the following: a traffic capacity, a power usage, or a transition time. In an example, the information related to each of the plurality of modes is received from one of: the radio unit, a network entity, a network function, an operations and maintenance entity. In an example, the apparatus comprises: means for receiving, from the radio unit, a further indication that the radio unit has completed the change from the second mode to the first mode. In an example, one of: the first mode is associated with a higher traffic capacity than the second mode, the first mode is associated with a lower traffic capacity than the second mode. In an example, one of: the first mode is associated with a higher power usage than the second mode, the first mode is associated with a lower power usage than the second mode. In an example, the apparatus comprises: means for, based on determining the first mode for the radio unit, at least one of the following: changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, changing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode, or changing a maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, the means for determining traffic comprises at least one of the following: means for monitoring a buffer associated with the radio unit, or means for monitoring physical resource block usage associated with the radio unit. In an example, the means for determining the first mode comprises: means for determining the first mode based on at least one of the following: determining that traffic within the buffer has been below a threshold amount for a predetermined period of time, or determining that physical resource block usage has been below the threshold amount for a predetermined period of time, wherein the first mode is associated with a capacity sufficient to provision the determined traffic. In an example, the means for determining the first mode comprises: means for determining the first mode based on at least one of the following: determining that traffic within the buffer has been above a threshold amount for a predetermined period of time, or determining that physical resource block usage has been above the threshold amount for a predetermined period of time, wherein the first mode is associated with a capacity sufficient to provision the determined traffic. In an example, the apparatus comprises: means for, based on the providing, starting a timer associated with the first mode; and means for, based on the timer expiring, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode. In an example, the means for, based on the timer expiring, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode comprises: means for, based on the timer expiring and at a subsequent scheduling period, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode. In an example, the value of the timer is preconfigured at the apparatus. In an example, the timer is associated with a transition from the second mode to the first mode at the radio unit, or a transition from the first mode to the second mode at the radio unit. In an example, the apparatus comprises: means for, based on the further indication, increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, the means for, based on the further indication, increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode comprises: means for, based on the further indication and at a subsequent scheduling period, increasing the maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, one of: the apparatus is for a distributed unit, the apparatus is comprised in a distributed unit, the apparatus is a distributed unit. In an example, the distributed unit controls the radio unit. In an example, the distributed unit and the radio unit are of a base station. According to an aspect, there is provided an apparatus comprising: means for receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode; and means for, based on the indication, activating the first mode. In an example, the means for, based on the indication, activating the first mode comprises: means for, based on the indication, changing from the second mode to the first mode. In an example, the apparatus comprises: means for providing, to the distributed unit, information related to first mode and the second mode, wherein the information for each modes comprises at least one of the following: a traffic capacity, a power usage, or a transition time. In an example, the apparatus comprises: means for providing, to the distributed unit, a further indication that the radio unit has completed the change from the second mode to the first mode. In an example, one of: the first mode is associated with a higher traffic capacity than the second mode, the first mode is associated with a lower traffic capacity than the second mode. In an example, one of: when the first mode is associated with a higher power usage than the second mode, the first mode is associated with a lower power usage than the second mode. In an example, one of: the apparatus is for a radio unit, the apparatus is comprised in a radio unit, the apparatus is a radio unit. According to an aspect, there is provided a method comprising: determining traffic associated with a radio unit; determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes; and providing, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode. In an example, the traffic capacity of the radio unit associated with each mode of the plurality of modes is related to a power usage of the radio unit. In an example, the first mode is associated with a different traffic capacity and power usage than the second mode. In an example, a lower traffic capacity corresponds to a lower power usage, and vice-versa. In an example, the determining traffic associated with a radio unit comprises at least one of the following: detecting traffic associated with the radio unit, measuring traffic associated with the radio unit, estimating traffic associated with the radio unit, or predicting traffic associated with the radio unit. In an example, the method comprises: receiving information related to each of the plurality of modes, wherein the information for each of the plurality of modes comprises at least one of the following: a traffic capacity, a power usage, or a transition time. In an example, the information related to each of the plurality of modes is received from one of: the radio unit, a network entity, a network function, an operations and maintenance entity. In an example, the method comprises: receiving, from the radio unit, a further indication that the radio unit has completed the change from the second mode to the first mode. In an example, one of: the first mode is associated with a higher traffic capacity than the second mode, the first mode is associated with a lower traffic capacity than the second mode. In an example, one of: the first mode is associated with a higher power usage than the second mode, the first mode is associated with a lower power usage than the second mode. In an example, the method comprises: based on determining the first mode for the radio unit, at least one of the following: changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, changing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode, or changing a maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, the determining traffic comprises at least one of the following: monitoring a buffer associated with the radio unit, or monitoring physical resource block usage associated with the radio unit. In an example, the determining the first mode comprises: determining the first mode based on at least one of the following: determining that traffic within the buffer has been below a threshold amount for a predetermined period of time, or determining that physical resource block usage has been below the threshold amount for a predetermined period of time, wherein the first mode is associated with a capacity sufficient to provision the determined traffic. In an example, the determining the first mode comprises: determining the first mode based on at least one of the following: determining that traffic within the buffer has been above a threshold amount for a predetermined period of time, or determining that physical resource block usage has been above the threshold amount for a predetermined period of time, wherein the first mode is associated with a capacity sufficient to provision the determined traffic. In an example, the method comprises: based on the providing, starting a timer associated with the first mode; and based on the timer expiring, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode. In an example, the based on the timer expiring, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode comprises: based on the timer expiring and at a subsequent scheduling period, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode. In an example, the value of the timer is preconfigured at the apparatus. In an example, the timer is associated with a transition from the second mode to the first mode at the radio unit, or a transition from the first mode to the second mode at the radio unit. In an example, the method comprises: based on the further indication, increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, the based on the further indication, increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode comprises: based on the further indication and at a subsequent scheduling period, increasing the maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, one of: the method is performed by a distributed unit. In an example, the distributed unit controls the radio unit. In an example, the distributed unit and the radio unit are of a base station. According to an aspect, there is provided a method comprising: receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode; and based on the indication, activating the first mode. In an example, the based on the indication, activating the first mode comprises: based on the indication, changing from the second mode to the first mode. In an example, the method comprises: providing, to the distributed unit, information related to first mode and the second mode, wherein the information for each modes comprises at least one of the following: a traffic capacity, a power usage, or a transition time. In an example, the method comprises: providing, to the distributed unit, a further indication that the radio unit has completed the change from the second mode to the first mode. In an example, one of: the first mode is associated with a higher traffic capacity than the second mode, the first mode is associated with a lower traffic capacity than the second mode. In an example, one of: when the first mode is associated with a higher power usage than the second mode, the first mode is associated with a lower power usage than the second mode. In an example, one of: the method is performed by a radio unit. According to an aspect, there is provided an apparatus comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: determining traffic associated with a radio unit; determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes; and providing, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode. In an example, the traffic capacity of the radio unit associated with each mode of the plurality of modes is related to a power usage of the radio unit. In an example, the first mode is associated with a different traffic capacity and power usage than the second mode. In an example, a lower traffic capacity corresponds to a lower power usage, and vice-versa. In an example, the determining traffic associated with a radio unit comprises at least one of the following: detecting traffic associated with the radio unit, measuring traffic associated with the radio unit, estimating traffic associated with the radio unit, or predicting traffic associated with the radio unit. In an example, the apparatus is caused to perform: receiving information related to each of the plurality of modes, wherein the information for each of the plurality of modes comprises at least one of the following: a traffic capacity, a power usage, or a transition time. In an example, the information related to each of the plurality of modes is received from one of: the radio unit, a network entity, a network function, an operations and maintenance entity. In an example, the apparatus is caused to perform: receiving, from the radio unit, a further indication that the radio unit has completed the change from the second mode to the first mode. In an example, one of: the first mode is associated with a higher traffic capacity than the second mode, the first mode is associated with a lower traffic capacity than the second mode. In an example, one of: the first mode is associated with a higher power usage than the second mode, the first mode is associated with a lower power usage than the second mode. In an example, the apparatus is caused to perform: based on determining the first mode for the radio unit, at least one of the following: changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, changing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode, or changing a maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, the determining traffic comprises at least one of the following: monitoring a buffer associated with the radio unit, or monitoring physical resource block usage associated with the radio unit. In an example, the determining the first mode comprises: determining the first mode based on at least one of the following: determining that traffic within the buffer has been below a threshold amount for a predetermined period of time, or determining that physical resource block usage has been below the threshold amount for a predetermined period of time, wherein the first mode is associated with a capacity sufficient to provision the determined traffic. In an example, the determining the first mode comprises: determining the first mode based on at least one of the following: determining that traffic within the buffer has been above a threshold amountfor a predetermined period of time, or determining that physical resource block usage has been above the threshold amount for a predetermined period of time, wherein the first mode is associated with a capacity sufficient to provision the determined traffic. In an example, the apparatus is caused to perform: based on the providing, starting a timer associated with the first mode; and based on the timer expiring, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode. In an example, the based on the timer expiring, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode comprises: based on the timer expiring and at a subsequent scheduling period, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode. In an example, the value of the timer is preconfigured at the apparatus. In an example, the timer is associated with a transition from the second mode to the first mode at the radio unit, or a transition from the first mode to the second mode at the radio unit. In an example, the apparatus is caused to perform: based on the further indication, increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, the based on the further indication, increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode comprises: based on the further indication and at a subsequent scheduling period, increasing the maximum amount of traffic to be scheduled for the radio unit according to the first mode. In an example, one of: the apparatus is for a distributed unit, the apparatus is comprised in a distributed unit, the apparatus is a distributed unit. In an example, the distributed unit controls the radio unit. In an example, the distributed unit and the radio unit are of a base station. According to an aspect, there is provided an apparatus comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode; and based on the indication, activating the first mode. In an example, the based on the indication, activating the first mode comprises: based on the indication, changing from the second mode to the first mode. In an example, the apparatus is caused to perform: providing, to the distributed unit, information related to first mode and the second mode, wherein the information for each modes comprises at least one of the following: a traffic capacity, a power usage, or a transition time. In an example the apparatus is caused to perform: providing, to the distributed unit, a further indication that the radio unit has completed the change from the second mode to the first mode. In an example, one of: the first mode is associated with a higher traffic capacity than the second mode, the first mode is associated with a lower traffic capacity than the second mode. In an example, one of: when the first mode is associated with a higher power usage than the second mode, the first mode is associated with a lower power usage than the second mode. In an example, one of: the apparatus is for a radio unit, the apparatus is comprised in a radio unit, the apparatus is a radio unit. According to an aspect, there is provided a computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform at least the following: determining traffic associated with a radio unit; determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes; and providing, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode. According to an aspect, there is provided a computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode; and based on the indication, activating the first mode. According to an aspect, there is provided an apparatus comprising: circuitry configured to perform: determining traffic associated with a radio unit; circuitry configured to perform: determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes; and circuitry configured to perform: providing, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode. According to an aspect, there is provided an apparatus comprising: circuitry configured to perform: receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode; and circuitry configured to perform: based on the indication, activating the first mode. A computer product stored on a medium may cause an apparatus to perform the methods as described herein. A non-transitory computer readable medium comprising program instructions, that, when executed by an apparatus, cause the apparatus to perform the methods as described herein. An electronic device may comprise apparatus as described herein. In the above, various aspects have been described. It should be appreciated that further aspects may be provided by the combination of any two or more of the various aspects described above. Various other aspects and further embodiments are also described in the following detailed description and in the attached claims. According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims. The embodiments that do not fall under the scope of the claims are to be interpreted as examples useful for understanding the disclosure. List of abbreviations: AF: Application Function AMF: Access and Mobility Management Function AN: Access Network BS: Base Station CN: Core Network CP: Control plane CU: Centralised unit DL: Downlink DRX: Discontinuous reception DTX: Discontinuous transmission DU: Distributed unit eNB: eNodeB gNB: gNodeB lloT: Industrial Internet of Things LTE: Long Term Evolution NEF: Network Exposure Function NG-RAN: Next Generation Radio Access Network NF: Network Function NR: New Radio NRF: Network Repository Function NW: Network MS: Mobile Station MNO: Mobile network operator O-RAN: Open-Radio access network PA: Power amplifier PCF Policy Control Function PLMN: Public Land Mobile Network PRB: Physical resource block QoS: Quality of service RAN: Radio Access Network RF: RFIC: RIC: RRC: Radio Frequency RF integrated circuit RAN intelligent controller Radio resource control 5 RT: Real time Non-RT: Non-Real time RU: Radio unit SMF: Session Management Function SoC: System-on-chip 10 UE: User Equipment UP: User plane UDR: Unified Data Repository UDM: Unified Data Management UL: Uplink 15 UPF: User Plane Function pDTX: micro discontinuous transmission 3GPP: 3rd Generation Partnership Project 5G: 5th Generation 5GC: 5G Core network 20 5G-AN: 5G Radio Access Network 5GS: 5G System Description of Figures Embodiments will now be described, by way of example only, with reference to 25 the accompanying Figures in which: Figure 1 shows a schematic representation of a 5G system; Figure 2 shows a schematic representation of a control apparatus; Figure 3 shows a schematic representation of a terminal; Figure 4a shows a schematic representation of a 5G RAN architecture and a 30 5G core network; Figure 4b shows a schematic representation of a functional split of a gNB for a 5G RAN architecture; Figure 5 shows a schematic representation of an O-RAN architecture; Figure 6 shows an example graphical representation of timing for mode changes at a radio unit for a fixed transition time; Figure 7 shows an example graphical representation of timing for mode changes at a radio unit for a variable transition time; Figure 8 shows an example signalling diagram for communications between a DU and an RU; Figure 9 shows an example method flow diagram performed by an apparatus; Figure 10 shows another example method flow diagram performed by an apparatus; and Figure 11 shows a schematic representation of a non-volatile memory medium storing instructions which when executed by a processor allow a processor to perform one or more of the steps of the method of Figure 9 and / or Figure 10. Detailed description Before explaining in detail some examples of the present disclosure, certain general principles of a wireless communication system and mobile communication devices are briefly explained with reference to Figures 1 to 3 to assist in understanding the technology underlying the described examples. In a wireless communication system 100, such as that shown in Figure 1, mobile communication devices / terminals or user apparatuses, and / or user equipments (UE), and / or machine-type communication devices 102 are provided wireless access via at least one base station (not shown) or similar wireless transmitting and / or receiving node or point. A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other devices. The communication device may access a carrier provided by a station or access point, and transmit and / or receive communications on the carrier. In the following, certain examples are explained with reference to mobile communication devices capable of communication via a wireless cellular system and mobile communication systems serving such mobile communication devices. Before explaining in detail the examples of the disclosure, certain general principles of a wireless communication system, access systems thereof, and mobile communication devices are briefly explained with reference to Figures 1, 2 and 3 to assist in understanding the technology underlying the described examples. Figure 1 shows a schematic representation of a wireless communication system 100. The wireless communication system 100 comprises one more devices 102 such as user equipments (UEs), or terminals. The wireless communication system 100 also comprises a 5G system (5GS), as shown in Figure. The 5GS comprises a 5G radio access network (5G-RAN) 106, a 5G core network (5GC) 104 comprising one or more network functions (NF), one or more application functions (AFs) 108, and one or more data networks (DNs) 110. The 5G-RAN 106 may comprise one or more gNodeB (gNB) distributed unit (DU) functions connected to one or more gNodeB (gNB) centralized unit (CU) functions. The DU-CU split will be described in more detail below, alongside Figures 4a and 4b. The 5GC 104 comprises an access management function (AMF) 112, a session management function (SMF) 114, an authentication server function (AUSF) 116, a user data management (UDM) 118, a user plane function (UPF) 120, a network exposure function (NEF) 122 and / or other NFs. Some of the examples as shown below may be applicable to 3GPP 5G standards. However, some examples may also be applicable to 5G-advanced, 4G, 3G and other 3GPP standards. For example, other 3GPP standards may include future 3GPP technology including 6G, 7G, etc. In a wireless communication system 100, such as that shown in Figure 1, mobile communication devices / terminals or user apparatuses, and / or user equipments (UE), and / or machine-type communication devices are provided with wireless access via at least one base station or similar wireless transmitting and / or receiving node or point. The terminal is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other devices. The communication device may access a carrier provided by a base station or access point, and transmit and / or receive communications on the carrier. Figure 2 illustrates an example of a control apparatus 200. The control apparatus 200 may be for controlling a function of one or more network entities / network functions, such as the entities of the 5G-RAN or the 5GC as illustrated on Figure 1. The control apparatus 200 may control a DU of a 5G-RAN. A separate instance of the control apparatus 200 may control a CU of the 5G-RAN. The control apparatus 200 comprises at least one random access memory (RAM) 211 a, at least one read only memory (ROM) 211 b, at least one processor 212, 213 and an input / output interface 214. The at least one processor 212, 213 is coupled to the RAM 211a and the ROM 211b. The at least one processor 212, 213 may be configured to execute an appropriate software code 215. The software code 215 may for example allow to perform one or more steps to perform one or more of the present aspects or examples. The software code 215 may be stored in the ROM 211b. The control apparatus 200 may be interconnected with another control apparatus 200 controlling another entity / function of the 5G-AN or the 5GC. In some examples, each function of the 5G-AN or the 5GC comprises a control apparatus 200. In alternative examples, two or more functions of the 5G-AN or the 5GC may share a control apparatus. The control apparatus 200 may comprise one or more circuits, or circuitry (not shown) which may be configured to perform one or more of the present aspects or examples. Figure 3 illustrates an example of a terminal 300, such as the UE / terminal illustrated in Figure 1. The terminal 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples of a terminal are a user equipment, a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, a machine-type communications (MTC) device, a Cellular Internet of things (CloT) device or any combinations of these or the like. The terminal 300 may provide, for example, communication of data for carrying communications. The communications may be one or more of voice, electronic mail (email), text message, multimedia, data, machine data and so on. The terminal 300 may receive signals over an air or radio interface 307 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 3, a transceiver apparatus is designated schematically by block 306. The transceiver apparatus 306 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device. The terminal 300 may be provided with at least one processor 301, at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 302b and the ROM 302a. The at least one processor 301 may be configured to execute an appropriate software code 308. The software code 308 may for example allow to perform one or more of the present aspects. The software code 308 may be stored in the ROM 302a. The terminal 300 may comprise one or more circuits, or circuitry (not shown) which may be configured to perform one or more of the present aspects or examples. The processor, storage and other relevant control apparatus may be provided on an appropriate circuit board and / or in chipsets. This feature is denoted by reference 304. The device may optionally have a user interface such as keypad 305, touch sensitive screen or pad, combinations thereof or the like. Optionally one or more of a display, a speaker and a microphone may be provided depending on the type of the device. Due to the exponential increase in wireless network traffic, the increasing performance demands (e.g. coverage, throughput, latency), the increasing operational expenditure, and the increasing cost of energy, many mobile network operators (MNOs) are targeting a balance between service quality and network energy consumption. Network energy saving may be achieved by optimising the network operations through advanced algorithms for energy efficiency using, for example, sleep modes. Sleep or muting modes are beneficial in the radio unit (RU), which consumes the most power / energy in a base station (e.g. gNB). A power amplifier (PA) module of the RU is often the highest energy consuming module in a radio unit (RU) of the gNB. With the introduction of massive multiple input / multiple output (MIMO) technology in 5G, the energy consumption of the radio unit (RU) is further increased due to the presence of a large antenna array. Use of sleep modes and muting techniques that shutdown some (or all) of the hardware (HW) components help to reduce energy consumption especially at low to medium load scenarios, where network capacity demands are lower. In 5G, RAN architecture is split into functional units, namely a distributed unit (DU) and a centralised unit (CU). Another component of the RAN architecture in a radio unit (RU). The purpose of the RU is to convert radio signals sent to and from an antenna to a digital signal that can be transmitted over the fronthaul to the DU. One or more RUs can be controlled by a DU. A DU may be responsible for real-time layer 1 (L1) and L2 scheduling functions, while a CU may be responsible for non-real time, higher L2 and L3. A DU’s server and relevant software may be hosted on a site itself or can be hosted in an edge cloud (e.g. data center or central office) depending on transport availability and fronthaul interface. A CU’s server and relevant software may be co-located with the DU, or may be hosted in a regional cloud data center (remote from the DU). The actual split between DU and RU may be different depending on the specific use-case and implementation. Figure 4a shows a schematic representation of a 5G RAN architecture and a 5G core network. There is provided a 5GC 401 and an NG-RAN 403. The 5GC 401 and NG-RAN 403 are able to communicate with each other through NG interfaces. The NG-RAN 403 comprises two gNBs 405. The gNBs 405 are linked with an Xn-C interface. One of the gNBs 405 comprises a gNB-CU 407 and two gNB-DUs 409. The two gNB-DUs 409 are connected to one or more RUs (not shown). The two gNB-DUs 409 are linked to the gNB-CU 407 through F1 interfaces. Figure 4b shows a schematic representation of a functional split of a gNB for a 5G RAN architecture. There is provided a RU 451 which is linked with a DU 453. The RU 451 and DU 453 may communicate with each other. The link between the RU 451 and the DU 453 is referred to as the ‘fronthaul’. The DU 453 is also linked to a CU 455. The link between the DU 453 and the CU 455 is referred to as the ‘midhaul’. The RU 451, the DU 453, and the CU 455 may together form a gNB. The CU 455 is also linked to a 5GC 457. The link between the CU 455 and the 5GC 457 is referred to as the ‘backhaul’. Open Radio Access Network (O-RAN) is a disaggregated approach to deploying mobile fronthaul and midhaul networks built on cloud native principles. O-RAN is an evolution of the Next Generation RAN (NG-RAN) architecture, which was first introduced in 3GPP release 15 technical specification TS 38.401. The O-RAN Alliance was formed to undertake the advancement of NG-RAN, and expanding on the scope that was originally outlined by the 3GPP. Figure 5 shows a schematic representation of an O-RAN architecture. The system 500 comprises a session management and orchestration (SMO) 501 framework which has a real time RAN intelligent controller (RIC) 503. The real time RIC 503 interfaces a near real-time RC 505. The near real-time RIC 505 interfaces Y1 consumers 507 and an open-eNB (O-eNB) 509. A ‘Y1 consumer’ is a service consumers entity. A Y1 interface allows the Y1 consumers to subscribe to, or request, the RAN analytics information service(s) provided by near-RT RIC 505. The near real-time RIC 505 also interfaces an open centralised unit control plane (O-CU-CP) 511. The O-CU-CP 511 interfaces an open control unit user plane (O-CU-UP) 513 and an O-DU 515. The O-CU-CP 511 also has a number of 3GPP interfaces. The O-CU-UP 513 interfaces the near real time RIC 505 and the O-DU 515. The O-CU-UP 513 also has a number of 3GPP interfaces. The O-DU 515 interfaces an O-RU 517. The O-RU 517 interfaces the SMO 501. The SMO 501 also interfaces the O-eNB 509 and an O-Cloud 519. In some systems, an O-RU may expose its sleep mode capabilities to an O-DU. Next, the O-DU can expose a set of commonly supported sleep modes to an SMO and a non-real-time RIC (via an SMO) and / or the near-RT RIC which is available for utilization during operation. Information exposed towards the Non-RT and / or Near-RT RIC may include a unique identifier of each sleep mode, and additional operational parameters. Examples of operational parameters include: minimum duration of activation, transition times between SMs, whether to be applied on uplink (UL) / downlink (DL), etc. However, these systems do not provide a way to control sleeps modes, using the RIC, and between the DU and RU. In the RAN, an RU may spend a considerable amount of time in low traffic loading conditions. This is because the RU is typically configured for the ‘busy hour’, which occupies small part of the 24-hour traffic profile of a cell. In order to minimize RU power consumption in those low traffic loading conditions, several parts of RU may be powered-off, or turned off, while maintaining I balancing QoS. For example, hardware (HW) components like antenna, or power amplifiers. However, the powering-off of these HW components (and their later reactivation) often takes more time the more components are powered off. For example, micro-cuts in a power amplifier (PA) may be performed almost instantaneously, rather than a ‘full’ power-off of the PA. A powering-off of a radio frequency integrated circuit (RFIC) and / or a system on chip (SoC) may also take more time, similar to the PA. The RU does not have visibility of the current and / or future traffic demands. Therefore, the RU is unaware of whether there will be enough time to power off components or switch to a power saving mode (and back). This lack of control at the RU may lead to QoS impacts and reduce power saving potential. However, if the RU does power off components, and / or switch modes, then a DU controlling the RU may attempt to schedule traffic to or from the RU using currently unavailable resources of the RU. This would lead be to problems in the gNB, such as overloading and increased latencies. One or more of the following examples aims to address one or more of the problems identified above. In examples, there is provided an apparatus (e.g. for a distributed unit) that is configured for determining traffic associated with a radio unit, and determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes. The apparatus is further configured for providing, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode. In some examples, a DU detects a traffic level for a RU that the DU controls, including current traffic and / or traffic anticipated in near future. In some examples, a DU determines a suitable / most optimal power mode for an RU based on detected RU traffic and an available traffic capacity of the RU associated to each power mode. Traffic capacity may be a capability of an RU to deal with / process data traffic. A volume of (data) traffic may not exceed the traffic capacity of the RU. Traffic capacity for an RU may refer to a maximum amount of data / information transfer limit of the RU at any given point / time. In some examples, there is signalling from a DU to an RU to configure the RU to enter, or switch to, a determined power mode. In some examples, a traffic detector in a DU determines that RU traffic level is below a threshold for a time duration to switch the RU to a lower capacity and power saving mode. Once traffic demand is detected to increase above a threshold, the traffic detector triggers a switch of the RU back to a higher capacity mode (i.e. less power saving). In some examples, Dll-RU signalling is provided to synchronize DU and RU to ensure that the DU does not use unavailable capacity of the RU during a low capacity mode. A time period (e.g. a ‘transition time’) used by the RU to switch to a different mode may exceed a scheduling time window. During the transition time for switching mode, the unavailable resources should not be used for scheduling by the DU. In order to switch the power mode, the DU sends an indication / command to the RU to switch mode. In some examples, an RU sends an indication / acknowledgement of the mode switch to the DU after it is complete, in order to ensure synchronisation between the DU and RU. In some examples, when a traffic level is determined to be very low and it is determined that a geographical area could be served by another RU, a DU may determine to switch a cell (or cells) served by a RU off. The DU may indicate for the RU to switch / change entire components, or parts of the components, to a ‘deep’ sleep mode in some examples. For example, the ‘deep’ sleep mode may comprise the components using a small amount of power, or no power. In some examples, multiple levels of low capacity modes and power save modes are utilised to account for energy saving features such as, for example: micro discontinuous transmission (pDTX), cell DTX / cell discontinuous reception (DRX), (which corresponds to a time-domain resource ‘muting’), massive MIMO (mMIMO) antenna muting (which corresponds to a spatial-domain resource ‘muting’), bandwidth muting (which corresponds to a frequency-domain resource ‘muting’), transmit power reduction (which corresponds to a power-domain resource ‘muting’). These examples will be described in more detail below. Some power modes (which may also be referred to as ‘power states’) to be applied at an RU for reduced energy consumption may be applied instantaneously. For example, by setting beam-weights corresponding to some antenna elements / TRX to zero at an RU, it would reduce power consumption at the RU. The setting of these beam-weights could be applied near-instantaneously. However, in order to enable further energy saving modes or operations, a non-zero transition time is expected to enter a power mode for energy saving. Transition times experienced at the RU when switching between two power modes is shown in Figures 6 and 7. Figures 6 and 7 show example scenarios of fixed and variable transition times respectively. In some examples, a transition time may be longer or shorter than a scheduling period of a DU, but this transition time is to be synchronized with the scheduling period. This is because, during a mode change / state change from a first to a second mode, an RU is powering off certain components / parts, and only the components that are left active / powered in a lower power mode of the two involved mode should be considered as available during the transition time. The transition time to enter and / or exit a given power mode in an RU may be fixed or variable depending on the implementation details. A DU may be aware or unaware of the RU transition time associated with each of the power modes. After being configured to apply or switch to a different power mode than the current mode, an RU may provide an indication to the DU when the mode has been successfully changed. This may be referred to as a ‘feedback signal’ or ‘acknowledgment’. The feedback signal of mode change completion from RU to DU may be omitted in examples whereby the RU transition time is fixed and DU is aware of this time. In some examples, the DU may request and receive information of the available / supported power modes (and transition times) of a RU during an RU configuration procedure. This will be described in more detail alongside Figures 6 and 7. Figure 6 shows an example graphical representation of timing for mode changes at a radio unit for a fixed transition time. Figure 6 shows operations for an RU and a DU, wherein the RU is controlled by the DU. For the example of Figure 6, it is assumed that the transition time at the RU for changing modes is fixed and that the DU is aware of the fixed transition time(s). In the following example, the term “transition time” is used. In other examples, the terms “change time”, “changing time”, “switch time”, “switching time”, etc., may be used interchangeably. In the example of Figure 6, the RU is shown as operating in one of two modes, a ‘high capacity mode’ (i.e. a first mode) and a ‘low capacity mode’ (i.e. a second mode). The first mode (high capacity mode) has a higher capacity compared to the second mode (low capacity mode). For example, in the ‘high capacity mode’ all components of the RU are powered on, and in the ‘low capacity mode’ half of the components of the RU are powered off. It should be understood that this is shown as an example only. In other examples, the RU is configured with more than two different modes. For example, more than one ‘high capacity mode’ and / or more than one ‘low capacity mode’, or a plurality of different modes (wherein each mode has a different capacity. Each mode is associated with a power usage, a supported capacity, and a transition time. In examples whereby multiple modes are supported for a high capacity and / or a low capacity, the DU determines which one of the modes should be used at a given time based on, for example, the amount of measured or estimated traffic, so to maximize energy saving while been able to provision the demanded traffic. This is also applicable to Figure 7 discussed below. Figure 6 shows an RU mode / state 601, DU-RU signalling 603, and a DU scheduler mode / state 605, over time. At time zero (tO), the RU is operating with the ‘high capacity mode’. The DU is scheduling, for the RU, a ‘high capacity’. At t1, the DU detects / determines traffic associated with the RU. The DU detects ‘low’ traffic associated with the RU. The detecting may comprise monitoring a buffer associated with the radio unit. The detecting may comprise monitoring physical resource block usage associated with the radio unit. The detecting of ‘low traffic’ may comprise determining that traffic within the buffer has been below a threshold amount for a predetermined period of time. The detecting of ‘low traffic’ may comprise determining that physical resource block usage has been below the threshold amount for a predetermined period of time. Alternatively or additionally, the determining may comprise predicting / estimating that traffic within the buffer will remain within a threshold amount for a predetermined period of time in the future. At t2, which is the next scheduling period following the detection of the low traffic, a scheduler of the DU reduces the scheduling capacity for the RU. The DU may switch to ‘low capacity’ scheduling for the RU. A scheduling period is shown with label 607. DU scheduler state changes are synchronised with scheduling periods of the DU. This is shown with label 651. At t3, the DU provides an indication (which may be in the form of a request or instruction) to the RU to switch mode to a given ‘low capacity mode’. The ‘low capacity mode’ is supported by the RU. In some examples, the DU provides the indication to the RU at the same time as the scheduling capacity is reduced (i.e. t2 and t3 occur at the same time), or the indication is provided subsequently. Based on the received indication, the RU changes from the ‘high capacity mode’ to the ‘low capacity mode’. The change from the ‘high capacity mode’ to the ‘low capacity mode’ will take a certain amount of time, referred to as the ‘transition time’. A transition time may be nearly instantaneous (e.g. a few microseconds) in some examples. In other example, a transition time may be longer, or shorter, than a few microseconds. During a mode change / state change, the RU will be in the lower capacity of the two modes because the RU is powering down parts / powering up parts (e.g. HW components / subcomponents) during the mode change, which will not be available for scheduling (e.g. transmission / reception operations) during this transition time. Therefore, at t3, the RU will be in ‘low capacity mode’ as soon as the switch starts. In some examples, the RU provides an indication to the DU that the change has completed (at the end of the transition time). At t4, the DU detects traffic associated with the RU. The DU detects a ‘high’ amount of traffic. The detection of ‘high’ traffic may comprise determining that traffic is above a threshold amount for a predetermined amount of time. Alternatively or additionally, the DU may estimate / predict an increase of traffic / a high amount of traffic in a subsequent time window. At t5, the DU provides an indication to the RU to change to the ‘high capacity mode’. The providing of the indication is based on the detection of the high traffic. Based on receiving the indication, the RU changes to the ‘high capacity mode’. During the change to the ‘high capacity mode’ (i.e. during the transition time), the components being powered on will not be available until the end of the transition time. At the end of the transition time (i.e. completion of the change of modes), the RU may provide an indication of the completed mode change to the DU. At t6, the scheduler of the DU increases the scheduling capacity associated with the RU. The increase of the scheduling is based on the transition time, and the time the indication to change mode that was sent to the DU. Said another way, the DU increases the scheduling capacity for the RU once the transition time has expired. In some examples, the scheduler will change the scheduling capacity for the RU once the transition time has expired and at the next scheduling period. In the example of Figure 6, the DU does not rely on an indication / feedbackfrom the RU regarding a completed mode change as the DU is aware of the fixed transition time. The scheduler of the DU changes scheduling capacity / scheduling mode after a set time delay, which is long enough to ensure that the RU mode has changed. This is shown with label 653. Figure 7 shows an example graphical representation of timing for mode changes at a radio unit for a variable transition time. Figure 7 shows operations for an RU and a DU, wherein the RU is controlled by the DU. For the example of Figure 7, it is assumed that the transition time at the RU for changing between two modes is variable, and so the DU is not aware of the transition time. In the following example, the term “transition time” is used. In other examples, the terms “change time”, “changing time”, “switch time”, “switching time”, etc., may be used interchangeably. In the example of Figure 7, the RU is shown as operating in one of two modes, a ‘high capacity mode’ (i.e. a first mode) and a ‘low capacity mode’ (i.e. a second mode). The first mode (high capacity mode) has a higher capacity compared to the second mode (low capacity mode). For example, in the ‘high capacity mode’ all components of the RU are powered on, and in the ‘low capacity mode’ half of the components of the RU are powered off. It should be understood that this is shown as an example only. In other examples, the RU is configured with more than two different modes. Each mode is associated with a power usage, a capacity, and a transition time. Figure 7 shows an RU mode / state 701, DU-RU signalling 703, and a DU scheduler mode / state 705, over time. At time zero (tO), the RU is operating with the ‘high capacity mode’. The DU is scheduling, for the RU, a ‘high capacity’. At t1, the DU detects traffic associated with the RU. The DU detects ‘low’ traffic associated with the RU. The detecting may comprise monitoring a buffer associated with the radio unit. The detecting may comprise monitoring physical resource block usage associated with the radio unit. The determining of ‘low traffic’ may comprise determining that traffic within the buffer has been below a threshold amount for a predetermined period of time. The determining of ‘low traffic’ may comprise determining that physical resource block usage has been below the threshold amount for a predetermined period of time. At t2, which is the next scheduling period following the detection of the low traffic, a scheduler of the DU reduces the scheduling capacity for the RU. The DU may switch to ‘low capacity’ scheduling for the RU. A scheduling period is shown with label 607. DU scheduler state changes are synchronised with scheduling periods of the DU. This is shown with label 751. At t3, the DU provides an indication to the RU to switch mode to the ‘low capacity mode’. In some examples, the DU provides the indication to the RU at the same time as the scheduling capacity is reduced (i.e. t2 and t3 occur at the same time), or the indication is provided subsequently. Based on the received indication, the RU changes from the ‘high capacity mode’ to the ‘low capacity mode’. The change from the ‘high capacity mode’ to the ‘low capacity mode’ will take a certain amount of time, referred to as the ‘transition time’. During a mode change / state change, the RU will be in the lower capacity of the two modes because the RU is powering down parts / powering up parts during the mode change, and will not be available for scheduling during this transition time. Therefore, at t3, the RU will be in ‘low capacity mode’ as soon as the switch starts. At t4, the transition time has expired, and the RU has successfully changed to the ‘low capacity mode’. In response to this, the RU provides an indication to the DU that the RU has completed the change to the ‘low capacity mode’. As the scheduler of the DU has already switch to low capacity scheduling for the RU, the reception of the indication from the RU will not trigger any further actions at the DU. At t5, the DU detects traffic associated with the RU. The DU detects a ‘high’ amount of traffic for the RU. The detection of ‘high’ traffic may comprise determining that traffic is above a threshold amount for a predetermined amount of time. At t6, the DU provides an indication to the RU to change to the ‘high capacity mode’. The providing of the indication is based on the detection of the high traffic. Based on receiving the indication, the RU changes to the ‘high capacity mode’. During the change to the ‘high capacity mode’ (i.e. during the transition time), the components being powered on will not be available until the end of the transition time. At t7, at the end of the transition time (i.e. completion of the change of modes), the RU provides an indication of the completed mode change to the DU. Once the variable transition time has completed, the RU will be in the ‘high capacity mode’, and the components associated with the ‘high capacity mode’ will be available. At t8, based on the received indication from the RU, the scheduler of the DU increases the amount of scheduling available for the RU. For example, when the ‘high capacity mode’ is associated with all of the components of the RU being powered on, then the increasing of scheduling will comprise increasing the available scheduling to a maximum capacity for the RU. The scheduler of the DU may increase the scheduling for the RU at the next scheduling period following the reception of the indication from the RU. In this example, the increasing of the scheduling may be said to be based on the received indication and the next / subsequent scheduling period. Table 1 below shows when an indication or feedback signal from the RU to the DU may be provided to confirm the mode change has completed. Based on the scenarios (according to Table 1), the DU may configure the RU with the request for feedback. Variable RU transition time Fixed RU transition time DU unaware of transition time Feedback provided Feedback provided DU aware of transition time Feedback provided Feedback optional Table 1: RU to DU feedback signals for different scenarios In examples, the traffic detection performed by the DU of Figure 6 and / or Figure 7 may be implemented in several ways. The traffic detection method may vary, and any suitable method may be used. This would also include using artificial intelligence (Al)Zmachine learning (ML) based methods to predict incoming traffic in the near future (e.g. next tens of milliseconds). The traffic detection may comprise monitoring physical resource block (PRB) usage of the monitored RU. In some examples, the traffic monitoring is parameterized for performance optimization of both the throughput / capacity and power / energy. For example, relevant parameters for the traffic may include at least one of the following: a parameter associated with a high load (e.g. a high-load threshold amount), a parameter associated with a low load (e.g. a low-load threshold amount), a parameter associated with a time based on RU power state’s transition time (e.g. a predefined time window during which the traffic amount is measured, or for which it is estimated. In this way, for example, it may be determined that the associated low power mode can be entered without the risk of it being reverted too quickly). In one example, the traffic detection may estimate / predict the required capacity to be provisioned by the RU in one or more subsequent periods. Figure 8 shows an example signalling diagram for communications between a DU and an RU. In the example of Figure 8, the DU is split into a buffer (e.g. L2 buffer) and a scheduler (e.g. L2 scheduler). The L2 buffer and the L2 scheduler may be co-located in some examples. In other examples, the L2 buffer and the L2 scheduler are separate. The ‘L2 Buffer1 may correspond to a traffic detector in the DU, and the ‘L2 scheduler’ may correspond to the packet scheduler in the DU. There is also provided an RU. The RU is associated with the DU. The RU is controlled by the DU. At S801, the DU (at the L2 buffer) determines traffic associated with the RU. In some examples, the determining traffic associated with a radio unit comprises at least one of the following: detecting traffic associated with the radio unit, measuring traffic associated with the radio unit, estimating traffic associated with the radio unit, or predicting traffic associated with the radio unit. The detection of the traffic may comprise monitoring a buffer associated with the RU, or monitoring PRB usage associated with the RU. At S801, the DU detects a ‘low’ traffic. For example, traffic below a threshold amount. Alternatively or additionally the DU may estimate the ‘low’ traffic. The DU determines a first mode from a plurality of modes for the RU, wherein the determining of the first mode is based on the determined traffic and a traffic capacity supported by the RU associated with each mode of the plurality of modes. The traffic capacity of the RU associated with each mode is related to / linked to a power usage of the radio unit. For example, the power usage may be proportional to the traffic capacity for a mode. In an example, the first mode is associated with a different traffic capacity and power usage than the second mode. For example, a lower traffic capacity corresponds to a lower power usage, and vice-versa. Said another way, the DU determines that the first mode (e.g. low capacity mode / low power mode in this example) is suitable based on the determined ‘low’ traffic. The capacity of the mode should be adequate to meet the current / predicted capacity demand for the traffic and for quality of service (QoS)Zquality of experience (QoE). The DU uses the traffic capacity and parameters such as QoS and QoE in order to determine / select the mode. In this example, there are two different modes, namely the first mode and a second mode. Each of the first and second modes are associated with a capacity of the RU (also referred to as a ‘traffic capacity’ of the RU) (while in the mode) and power usage supported by the RU (while in the mode). For example, the first mode is associated with a lower power usage than the second mode. Said another way, the first mode is associated with a first traffic capacity / power usage for the RU and the second mode has a second traffic capacity / power usage for the RU, wherein the first traffic capacity / power usage is lower than the second traffic capacity / power usage. For example, the first mode may be half capacity, meaning that half of the components of the RU are powered off while in the first mode. The second mode may be a full capacity, meaning that all of the components are powered on while in the second mode. It should be understood that this is given as an example only to aid in the understanding of the invention. In other examples, there are more than two different modes configured at the RU, wherein each mode is associated with a power usage and capacity of the RU. Said another way, the DU has detected a low traffic for the RU (e.g. buffer is filled below a threshold), and the DU determines that the first mode (as a half capacity mode) is most suitable, in order to optimize (maximize) power / energy saving at the RU. At S802, an indication that the first mode has been determined, is provided to the L2 scheduler from the L2 buffer. At S803, the L2 scheduler of the DU reduces scheduling for the RU. The reduction of the scheduling is related to the first mode. For example, as the first mode is associated with a half capacity in this example, the scheduling for the RU may be halved. In some examples, based on determining the first mode for the RU, the L2 scheduler changes at least one radio parameter for the RU according to the first mode. For example, the changing of the at least one parameter may comprise: reducing a transmit power and / or reducing a modulation and coding scheme (MCS) set of values. A transmit power limitation in a low capacity mode is useful for optimizing the power amplifiers operation (“slow drain modulation”). In some examples, based on determining the first mode for the RU, the L2 scheduler masks at least one radio resource as available or unavailable for the radio unit according to the first mode. For example, some part of the frequency spectrum / a certain number of PRBs are masked as available or unavailable. For example, a maximum number of PRBs can be used for scheduling whereas the remaining PRBs are considered unavailable for scheduling. In some examples, based on determining the first mode for the RU, the L2 scheduler limits (reduces) a maximum amount of UEs to be scheduled (e.g. simultaneously) for the RU according to the first mode. In some examples, based on determining the first mode for the RU, the L2 scheduler reduces a maximum amount of traffic to be scheduled (e.g. simultaneously) for the RU according to the first mode. In some examples, the maximum simultaneous traffic amount that can be supplied may be related to bandwidth and the number of MIMO layers. Reducing the used bandwidth and / or MIMO layers are ways to save power. In this context, “simultaneously” may mean in the same scheduling interval. For example, in the same subframe, slot or mini-slot. In some examples, a spatial resolution limitation may be associated to the first mode as a way to save power. For example, by using a massive MIMO antenna array partially. In this way, certain L2 functionalises (e.g. a scheduler) may, in response to determining the first mode, reduce maximum transmit power and reduce spatial resolution, in addition or alternatively. At S804, the DU provides, to the RU, an indication to change to the first mode from the second mode. As described above, the first mode is associated with a different power usage than the second mode. At S805, once the RU has successfully changed to the first mode, the RU provides an indication to the DU that the first mode has been activated. The RU may provide the indication to the L2 scheduler of the DU (e.g. MAC layer). The indication is provided after the transition time associated with the change has expired. In other examples, the RU does not provide such indication. For example, the Rll may not provide the indication when the transition time to change to the first mode is fixed and the DU knows the fixed transition time. In other examples, even when the transition time to change to the first mode is fixed and the DU knows the fixed transition time, the RU provides the indication to the DU that the first mode has been activated. The indication may be a confirmation that the first mode has been activated at the RU, and no error has been encountered. At S806, the indication from the RU is also provided to the L2 buffer of the DU. At S807, the DU determines traffic associated with the RU. The determination may comprise monitoring a buffer associated with the RU, or monitoring PRB usage associated with the RU. At S807, the DU detects a ‘high’ traffic. For example, traffic above a threshold amount. The threshold amounts of S801 and S807 may be different in some examples. The threshold amounts of S801 and S807 may be the same in some examples. The threshold amounts of S801 and S807 may be the same with an offset or hysteresis applied, in some examples. The DU determines the second mode from the plurality of modes for the RU, wherein the determining of the second mode is based on the determined traffic and a traffic capacity of the RU associated with each mode of the plurality of modes. Said another way, the DU determines that the second mode is suitable based on the determined ‘high’ traffic. At S808, the L2 buffer of the DU provides an indication of the determined second mode for the RU. At S809, the DU provides, to the RU, an indication to change to the second mode from the first mode. As described above, the second mode is associated with a different traffic capacity / power usage than the first mode. At S810, once the RU has successfully changed to the second mode, the RU provides an indication to the DU that the second mode has been activated. The RU may provide the indication to the L2 scheduler of the DU. The indication is provided after the transition time associated with the change has expired. At S811, based on the indication from the RU, the scheduler of the DU increases the amount of traffic that could be scheduled for the RU. This may be termed increasing the capacity of the RU, in some examples. In some examples, the scheduler of the DU increases the scheduling for the RU after receiving the indication at a next / subsequent scheduling period of the DU (as seen in Figures 6 and 7). At S812, the L2 buffer is informed that the RU has successfully changed to the second mode. The signalling of Figure 8 shows the example scenario whereby the DU is unaware of the transition time. For example, when the transition time is variable, or the transition time is fixed and the DU in unaware of the transition time associated with the relevant mode switch. In examples, whereby the DU is aware of the transition time, the indications / feedback provided by the RU may not occur. When the DU is aware of the transition time associated with the relevant mode change, the DU will change the scheduling for the RU based on the known transition time. For example, the DU may start a timer when the indication is provided to the RU (e.g. S804 / S809), wherein the timer is related to the known transition time. When the timer expires, at the next scheduling period, the DU will increase or decrease the scheduling for the RU according to the relevant mode. It should be understood that in some examples, one or more of the signalling steps of Figure 8 may not be performed, or may be performed in a different order. One or more of the examples discussed above allows the DU to determine times of lower traffic for the RU, in order to instruct the RU to enter low power modes, in order to save energy. It also allows for synchronisation between a DU and an RU. The synchronisation means that the DU does not schedule traffic for the RU on resources that are not currently available on the RU. This reduces the chances of errors in scheduling, whereby said errors could lead to increased latencies in receptions and / or transmissions involving the RU and DU. In a similar manner, the synchronisation also means that the DU is able to schedule more traffic for the RU on resources immediately after they are made available again at the RU after switching to a high capacity mode. Figure 9 shows an example method flow performed by an apparatus. The apparatus may be comprised in a distributed unit. The apparatus may be for a distributed unit. The apparatus may be a distributed unit. The distributed unit may be part of / comprised in a base station (e.g. a gNB). In S901, the method comprises determining traffic associated with a radio unit. In S903, the method comprises determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes. In S905, the method comprises providing, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode. Figure 10 shows an example method flow performed by an apparatus. The apparatus may be comprised in a radio unit. The apparatus may be for a radio unit. The apparatus may be a radio unit. The radio unit may be part of / comprised in a base station (e.g. a gNB). In S1001, the method comprises receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode. In S1003, the method comprises, based on the indication, activating the first mode. Figure 11 shows a schematic representation of non-volatile memory media 1100a (e.g. computer disc (CD) or digital versatile disc (DVD)) and 1100b (e.g. universal serial bus (USB) memory stick) storing instructions and / or parameters 1102 which when executed by a processor allow the processor to perform one or more of the steps of the methods of Figure 9 and / or Figure 10. It is noted that while the above describes example embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention. The examples may thus vary within the scope of the attached claims. In general, some embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although embodiments are not limited thereto. While various embodiments may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. The examples may be implemented by computer software stored in a memory and executable by at least one data processor of the involved entities or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any procedures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The term “non-transitory”, as used herein, is a limitation of the medium itself (i.e. tangible, not a signal) as opposed to a limitation on data storage persistency (e.g. RAM vs ROM). As used herein, “at least one of the following:” and “at least one of: ” and similar wording, where the list of two or more elements are joined by “and”, or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all of the elements. The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi core processor architecture, as non-limiting examples. As used herein, the term “means for”, or “means configured to perform” (or similar) may be any means that are suitable for performing the feature. The “means” may be configured to perform one or more of the functions and / or method steps previously described. For example, the “means” may include one or more of: at least one processor, at least one memory, transceiver circuitry, antenna circuitry, etc. It should be understood that these are provided as non-limiting examples. Alternatively, or additionally some examples may be implemented using circuitry. The circuitry may be configured to perform one or more of the functions and / or method steps previously described. That circuitry may be provided in the base station and / or in the communications device. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analogue and / or digital circuitry); (b) combinations of hardware circuits and software, such as: (i) a combination of analogue and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as the communications device or base station to perform the various functions previously described; and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example integrated device. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device. The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of some embodiments. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings will still fall within the scope as defined in the appended claims.

Claims

1. An apparatus comprising:means for determining traffic associated with a radio unit;means for determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes; andmeans for providing, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode.

2. The apparatus according to claim 1, wherein the apparatus comprises:means for receiving information related to each of the plurality of modes, wherein the information for each of the plurality of modes comprises at least one of the following: a traffic capacity, a power usage, or a transition time.

3. The apparatus according to claim 1 or claim 2, wherein the apparatus comprises:means for receiving, from the radio unit, a further indication that the radio unit has completed the change from the second mode to the first mode.

4. The apparatus according to any of claims 1 to 3, wherein one of: the first mode is associated with a higher traffic capacity than the second mode, the first mode is associated with a lower traffic capacity than the second mode.

5. The apparatus according to any of claims 1 to 4, wherein one of: the first mode is associated with a higher power usage than the second mode, the first mode is associated with a lower power usage than the second mode.

6. The apparatus according to any of claims 1 to 5, wherein the apparatus comprises:means for, based on determining the first mode for the radio unit, at least one of the following: changing at least one radio parameter for the radio unit according tothe first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, changing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode, or changing a maximum amount of traffic to be scheduled for the radio unit according to the first mode.

7. The apparatus according to any of claims 1 to 6, wherein the means for determining traffic comprises at least one of the following:means for monitoring a buffer associated with the radio unit, ormeans for monitoring physical resource block usage associated with the radio unit.

8. The apparatus according to claim 7, wherein the means for determining the first mode comprises:means for determining the first mode based on at least one of the following: determining that traffic within the buffer has been below a threshold amount for a predetermined period of time, or determining that physical resource block usage has been below the threshold amount for a predetermined period of time,wherein the first mode is associated with a capacity sufficient to provision the determined traffic.

9. The apparatus according to claim 7 or claim 8, wherein the means for determining the first mode comprises:means for determining the first mode based on at least one of the following: determining that traffic within the buffer has been above a threshold amount for a predetermined period of time, or determining that physical resource block usage has been above the threshold amount for a predetermined period of time,wherein the first mode is associated with a capacity sufficient to provision the determined traffic.

10. The apparatus according to any of claims 1 to 9, wherein the apparatus comprises:means for, based on the providing, starting a timer associated with the first mode; andmeans for, based on the timer expiring, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode.

11. The apparatus according to claim 10, wherein the means for, based on the timer expiring, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode comprises:means for, based on the timer expiring and at a subsequent scheduling period, at least one of the following: increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode, changing at least one radio parameter for the radio unit according to the first mode, masking at least one radio resource as available or unavailable for the radio unit according to the first mode, or increasing a maximum amount of user equipments to be scheduled for the radio unit according to the first mode.

12. The apparatus according to claim 3, wherein the apparatus comprises: means for, based on the further indication, increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode.

13. The apparatus according to claim 12, wherein the means for, based on the further indication, increasing a maximum amount of traffic to be scheduled for the radio unit according to the first mode comprises:means for, based on the further indication and at a subsequent scheduling period, increasing the maximum amount of traffic to be scheduled for the radio unit according to the first mode.

14. The apparatus according to any of claims 1 to 13, wherein one of: the apparatus is for a distributed unit, the apparatus is comprised in a distributed unit, the apparatus is a distributed unit.

15. An apparatus comprising:means for receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode; andmeans for, based on the indication, activating the first mode.

16. The apparatus according to claim 15, wherein the means for, based on the indication, activating the first mode comprises: means for, based on the indication, changing from the second mode to the first mode.

17. The apparatus according to claim 15 or claim 16, wherein the apparatus comprises:means for providing, to the distributed unit, information related to first mode and the second mode, wherein the information for each modes comprises at least one of the following: a traffic capacity, a power usage, or a transition time.

18. The apparatus according to any of claims 15 to 17, wherein the apparatus comprises:means for providing, to the distributed unit, a further indication that the radio unit has completed the change from the second mode to the first mode.

19. The apparatus according to any of claims 15 to 18, wherein one of: the first mode is associated with a higher traffic capacity than the second mode, the first mode is associated with a lower traffic capacity than the second mode.

20. The apparatus according to any of claims 15 to 19, wherein one of: when the first mode is associated with a higher power usage than the second mode, the first mode is associated with a lower power usage than the second mode.

21. The apparatus according to any of claims 15 to 20, wherein one of: the apparatus is for a radio unit, the apparatus is comprised in a radio unit, the apparatus is a radio unit.

22. A method comprising:determining traffic associated with a radio unit;determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes; andproviding, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode.

23. A method comprising:receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode; and based on the indication, activating the first mode.

24. A computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform at least the following:determining traffic associated with a radio unit;determining a first mode from a plurality of modes for the radio unit, wherein the determining of the first mode is based on the determined traffic and a traffic capacity of the radio unit associated with each mode of the plurality of modes; andproviding, to the radio unit, an indication to change to the first mode from a second mode of the plurality of modes, wherein the first mode is associated with a different traffic capacity than the second mode.

25. A computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform at least the following:receiving, from a distributed unit, an indication to change to a first mode from a second mode, wherein the first mode is associated with a different traffic capacity than the second mode; and based on the indication, activating the first mode.

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