Patent Publication Number: US-2023164623-A1

Title: Application Function Node, Access and Mobility Management Function Node, System and Methods in a Communications Network

Description:
TECHNICAL FIELD 
     Embodiments herein relate to an application function node, an access and mobility management function node, a system and methods therein. In particular, they relate to handling a data session in a communication network. 
     BACKGROUND 
     In a typical wireless communication network, user equipment (UE), also known as wireless communication devices, mobile stations, stations (STA) and/or wireless devices, communicate via a Radio Access Network (RAN) with one or more core networks belonging to different network operators. The RAN covers a geographical area which is divided into areas or cell areas, with each area or cell area being served by a radio network node, e.g., a Wi-Fi access point or a Radio Base Station (RBS), which in some networks may also be called, for example, a NodeB, eNodeB or a gNodeB. The area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node communicates over an air interface operating on radio frequencies with the UE within range of the radio network node. 
     A Universal Mobile Telecommunications System (UMTS) is a third generation telecommunication network, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). The UMTS Terrestrial Radio Access Network (UTRAN) is essentially a RAN using Wideband Code Division Multiple Access (WCDMA) and/or High Speed Packet Access (HSPA) for user equipment. In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for third generation networks and UTRAN specifically, and investigate enhanced data rate and radio capacity. In some RANs, e.g. as in UMTS, several radio network nodes may be connected, e.g., by landlines or microwave, to a controller node, such as a Radio Network Controller (RNC) or a Base Station Controller (BSC), which supervises and coordinates various activities of the plural radio network nodes connected thereto. The RNCs are typically connected to one or more core networks. 
     Specifications for the Evolved Packet System (EPS) have been completed within the 3GPP and this work continues in the coming 3GPP releases. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E-UTRAN/LTE is a variant of a 3GPP radio access technology wherein the radio network nodes are directly connected to the EPC core network rather than to RNCs. In general, in E-UTRAN/LTE the functions of an RNC are distributed between the radio network nodes, e.g. eNodeBs in LTE, and the core network. As such, the RAN of an EPS has an essentially “flat” architecture comprising radio network nodes which can be connected directly to one or more core networks, i.e. they do not need to be connected to the core via RNCs. 
     With the emerging 5G technologies such as New Radio (NR), the use of a large number of transmit- and receive-antenna elements is of great interest as it makes it possible to utilize beamforming, such as transmit-side and receive-side beamforming. Transmit-side beamforming means that the transmitter can amplify the transmitted signals in a selected direction or directions, while suppressing the transmitted signals in other directions. Similarly, on the receive-side, a receiver can amplify received signals coming from a selected direction or directions, while suppressing received unwanted signals coming from other directions. 
       FIG.  1    depicts various nodes in a 5G reference network architecture as defined by 3GPP. Some architectural nodes and aspects in  FIG.  1    that are relevant to this description include: Application Function (AF), Network Exposure Function (NEF), Policy Control Function (PCF), Session Management Function (SMF), User Plane Function (UPF) and Access and Mobility management Function (AMF). 
     The Application Function (AF) may interact with the 3GPP Core Network, and specifically when referred to in this disclosure, the AF may provision information to a network operator and to subscribe to certain events happening in an operator&#39;s network. 
     The Network Exposure Function (NEF) may support different functionality and as mentioned in this disclosure, the NEF may act as an entry point into the operator&#39;s network, so that the AF may interact with the 3GPP Core Network through the NEF. 
     The Policy Control Function (PCF) may support unified policy framework to govern the network behavior. For example in this disclosure, the PCF may provide PCC rules to the SMF. 
     The Session Management Function (SMF) may support different functionality, e.g. in this disclosure, the SMF may configure the UPF, e.g. for event reporting. The User Plane Function (UPF) may support handling of user plane traffic based on rules received from the SMF. For example in this disclosure, the UPF may handle packet inspection and different enforcement actions, e.g. event detection and reporting). 
     The AMF may receive all connection and session related information from the UE, e.g. via interface N1 or N2, but the AMF is responsible mainly for handling connection and mobility management tasks. 
     3GPP TS 29.518 defines the services offered by the AMF to other Network Functions (NF). 
     A Network Data Analytics Function (NWDAF) may represent an operator managed network analytics logical function. The NWDAF is part of the architecture specified in 3GPP TS 23.501 and may use various mechanisms and interfaces specified for 5GC and Operations Administration and Maintenance (OAM). 
     The NWDAF may interact with different entities for different purposes such as:
         Data collection based on event subscription, provided by the AMF, SMF, PCF, Unified Data Management (UDM), AF directly or via NEF, and OAM;   Retrieval of information from data repositories, e.g. from a Unified Data Repository (UDR) via UDM for subscriber-related information;   Retrieval of information about NFs e.g. Network Repository Function (NRF) for NF-related information, and Network Slice Selection Function (NSSF) for slice-related information; and   On demand provision of analytics to consumers.       

     It will now be described how optimization of user plane traffic can be addressed according to existing procedures. 
     There are multiple traffic algorithms to optimize the user plane traffic payload which contribute to improve the Quality of Experience (QoE) and ensure the required Quality of Service (QoS):
         Transmission Control Protocol (TCP) optimization: Most of the applications today are based on TCP transport, currently the TCP traffic presence is beyond 90% in mobile broadband networks. The TCP was developed in the 70s and was originally designed for wired communication and not for wireless communications. TCP may thus not be suitable for wireless networks, e.g. transmission errors are usually handled by the protocol as congestion events. Due to the above, different improvements to the TCP have been proposed, e.g. improved TCP congestion control algorithms such as TCP Cubic, Google&#39;s BBR, solutions based on TCP Proxy at the network side, AQM based solutions like CoDel, transparent solutions based on TCP split connection such as TCP ACK regulator or transparent buffer, etc. Most TCP optimizations aim for improved user experience by increasing TCP throughput, especially for high demanding services, as video streaming.   Domain Name System (DNS) optimization. DNS requests are required for every type of traffic. DNS optimizers can improve the time elapsed to get content.   Optimizers to ensure single user peak throughput for Augmented Reality (AR) applications, as high throughput may typically be needed for supporting AR applications.   Quick UDP Internet Connections (QUIC) optimization is similar to TCP optimization but tries to improve the QUIC throughput.       

     Some available congestion mechanisms include: TCP Cubic, BBR, TCP Reno, TCP New Reno, TCP Tahoe and Yeah. 
     The above-mentioned 5G New Radio (NR) will now be discussed. 
     Previous releases, e.g. 4G, 3G, 2G, can be useful in the same portions of the spectrum, e.g. with reorganized frequency bands. The 5G frequency band plans are more complex, as the frequency spectrum for sub-6 GHz 5G spans from 450 MHz to 6 GHz, and millimeter-wave 5G frequencies span from 24.250 GHz to 52.600 GHz, and also include unlicensed spectrum. 
     According to 3GPP TS 38.101-3 the frequency ranges in which NR can operate according to this version of the specifications are identified as shown in Table 1 below. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Definition of frequency ranges 
               
            
           
           
               
               
               
            
               
                   
                 Frequency 
                 Corresponding  
               
               
                   
                 range 
                 frequency 
               
               
                   
                 designation 
                 range 
               
               
                   
                   
               
               
                   
                 FR1 
                 410 MHz-7125 MHz 
               
               
                   
                 FR2 
                 24250 MHz-52600 MHz 
               
               
                   
                   
               
            
           
         
       
     
     Accordingly, the congestion control schemes in prior art are not completely equipped to handle the highly volatile millimetre Wave (mmWave). The mmWawe spectrum refers to a band of spectrum between 30 GHz and 300 GHz channels. A common congestion control protocol that can be used for most of the expected data traffic is TCP Cubic. TCP Cubic treats packet loss as the signal for congestion in the network. When introducing link outages and capacity variations, which are fairly common in mmWave channels, TCP Cubic fails. When bottleneck buffers are large, loss-based congestion control, like TCP Cubic, keeps the buffers full, causing so-called buffer bloat, and when the buffers are small, loss-based congestion control can further reduce throughput by multiplicative decrease depending on packet loss. If a greater amount of packet loss occurs, throughput will be reduced. 
     The role and purpose of congestion control is to regulate the amount of injected traffic in the network according to its congestion state. However, in wireless communications, traditional congestion control protocols, such as TCP New Reno, are unable to differentiate between losses attributed to congestion and those attributed to transmission errors caused by a decay in channel quality. 
     Radio Link Control (RLC) buffer size may scale proportionally to Bandwidth-Delay Product (BDP) to achieve maximum TCP goodput, i.e. throughput of useful data. However, it is very challenging to properly dimension the buffers for mmWave links, given the rapid bandwidth variations between Line-Of-Sight (LOS) and Non-Line-Of-Sight (NLOS) conditions, and to protect from link losses without introducing buffer bloat. 
     SUMMARY 
     An object of embodiments herein is to handle communication in a communication network in an efficient manner. 
     According to a first aspect of embodiments herein, the object is achieved by a method performed an AF node for handling a data session for a UE in a communication network. The AF node obtains information about usage of a first frequency for the UE from an AMF node. The AF node then applies a first congestion mechanism based on the obtained information about usage of the first frequency. The AF node further obtains information about usage of a second frequency for the UE from the AMF node. The AF node then further applies a second congestion mechanism in response to the obtained information about usage of the second frequency. 
     According to another aspect of embodiments herein, the object is achieved by a method performed by an AMF node for handling a data session for a UE in a communication network. The AMF node provides information about usage of a first frequency for the UE to an AF node. The AMF node then detects that usage of the frequency of the UE changes. The AMF node further provides information about usage of a second frequency for the UE to the AF node. 
     According to yet another aspect of embodiments herein, the object is achieved by an AF node for handling a data session for a UE in a communication network. The AF node is configured to obtain information about usage of a first frequency for the UE from an AMF node. The AF node is further configured to apply a first congestion mechanism based on the obtained information about usage of the first frequency. The AF node is further configured to obtain information about usage of a second frequency for the UE from the AMF node. The AF node is further configured to apply a second congestion mechanism in response to the obtained information about usage of the second frequency. 
     According to still another aspect of embodiments herein, the object is achieved by an AMF node for handling a data session of a UE in a communication network. The AMF node is configured to provide information about usage of a first frequency for the UE to an AF node. The AMF node is further configured to detect that usage of the frequency of the UE changes. The AMF node is further configured to provide information about usage of a second frequency for the UE to the AF node. 
     According to another aspect of embodiments herein, the object is achieved by a system for handling a data session for a UE in a communication network. 
     It is furthermore provided herein a computer program product comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out the method above, as performed by the network node or the UE. It is additionally provided herein a computer-readable storage medium, having stored thereon a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to the method above, as performed by the network node or the UE. 
     With the realisation that by obtaining information about usage of a first frequency for the UE from an AMF node, the AF node can apply a first congestion mechanism based on the obtained information about usage of the first frequency. By obtaining information about usage of a second frequency for the UE from the AMF node, the AF node can apply a second congestion mechanism in response to the obtained information about usage of the second frequency. Thereby the communication in the wireless communications network in handled in an efficient matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Examples of embodiments herein are described in more detail with reference to attached drawings in which: 
         FIG.  1    is a schematic overview depicting a 5G reference network architecture; 
         FIG.  2    is a schematic block diagram illustrating embodiments of a communications network; 
         FIG.  3    is a combined signalling scheme and flowchart according to some embodiments herein; 
         FIG.  4    is a flowchart depicting embodiments of a method in an application function node; 
         FIG.  5    is a flowchart depicting embodiments of a method in an access and mobility management node; 
         FIG.  6    is a combined signalling scheme and flowchart according to some embodiments herein; 
         FIGS.  7 A and  7 B  are combined signalling schemes and flowcharts according to some embodiments herein; 
         FIG.  8    is a schematic block diagram illustrating embodiments of an application function node; 
         FIG.  9    is a schematic block diagram illustrating embodiments of an access and mobility management function node; 
         FIG.  10    is a schematic block diagram illustrating embodiments of a system; 
         FIG.  11    schematically illustrates a telecommunication network connected via an intermediate network to a host computer; 
         FIG.  12    is a generalized block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection; and 
         FIGS.  13  to  16    are flowcharts illustrating methods implemented in a communication system including a host computer, a base station and a user equipment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  2    is a schematic overview depicting a communications network  100  wherein embodiments herein may be implemented. The communication network  100  is able to provide wireless services for communication devices e.g. a User Equipment (UE)  120 , such as a mobile station, a non-access point (non-AP) STA, a STA, a wireless device and/or a wireless terminal. It should be understood by those skilled in the art that “UE” is a non-limiting term which means any terminal, wireless communication terminal, user equipment, Machine Type Communication (MTC) device, Internet of Things operable device, Device to Device (D2D) terminal, mobile device e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or any device communicating within a cell or service area. 
     Network nodes operate in the core network, such as an Application Function node (AF)  131 , an Access and Mobility management Function node (AMF)  132 , a Network Exposure Function node (NEF)  133  and a User Plane Function (UPF) node  134 . These nodes have basically the following functions and tasks. 
     The AF node  131  may support application influence on traffic routing, accessing NEF, interaction with policy framework for policy control. 
     The AMF node  132  may support termination of Non-access stratum (NAS) signalling, NAS ciphering and integrity protection, registration management, connection management, mobility management, access authentication and authorization and security context management. 
     The NEF node  133  may support exposure of capabilities and events, secure provision of information from external application to 3GPP network and translation of internal/external information. 
     The UPF node  134  may support packet routing and forwarding, packet inspection, Quality of Service (QoS) handling and may be an anchor point for intra- and inter-RAT mobility. 
     There are also network nodes, in addition to those cited above, for providing radio coverage over a geographical area by means of antenna beams. The geographical area may be referred to as a cell, a service area, beam or a group of beams. These network nodes may in this case be a transmission and reception point e.g. a radio access network node such as a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNode B), an NR Node B (gNB), a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a transmission arrangement of a radio base station, a stand-alone access point, a Wireless Local Area Network (WLAN) access point, an Access Point Station (AP STA), an access controller, a UE acting as an access point or a peer in a Device to Device (D2D) communication, or any other network unit capable of communicating with a UE within the cell  11  served by the radio network node  110  depending e.g. on the radio access technology and terminology used. 
     The procedures and activities according to embodiments herein are chiefly performed by the AF node  131  and the AMF node  132 , as described herein. The communications network  100  may use 5G NR for radio access but may further use a number of other different technologies, such as, Wi-Fi, (LTE), LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. 
     The communication network  100  comprises one or more CNs  140  and one or more RANs  150 . The UE  120  is connected via one or more RANs  150 , to the one or more CNs  140 . 
     As an alternative, a Distributed Node (DN) and functionality, e.g. comprised in a cloud  130  as shown in  FIG.  2    may be used for performing or partly performing the methods. 
     In an example scenario of the handling of a data session for the UE  120  in the communication network  100  the AF node  131  may subscribe to changes in the radio frequency by subscribing to radio frequency events in the AMF node  132  through the NEF node  133 . Radio frequency events may relate to access mobility of the UE  120  such as location changes, the UE  120  moving in or out of a subscribed area of interest, time zone changes, access type changes, registration state changes, connectivity state changes, UE  120  loss of communication and UE  120  reachability status. The AMF node  132  may thereby send information about those events to the AF node  131 , via the NEF node  133 , so that the AF node  131  can apply the corresponding congestion window based on this information. 
     An example of how a data session could be handled for the UE  120  in the communication network  100  will now be described with reference to  FIG.  3   , thereafter methods will be described from the view of the AF node  131  and AMF node  132  respectively with reference to  FIGS.  4  and  5   .  FIG.  3    is a combined signalling scheme and flowchart of a procedure where some embodiments herein are used. The method e.g. comprises the following actions: 
     Action  301 . To be able to know what frequency the UE  120  is using, the AF node  131  obtains information about usage of a first frequency for the UE  120  from the AMF node  132 . Therefore the AF node  131  transmits, towards the NEF node  133 , a subscription request to a UE frequency event. The subscription request comprises a UE identifier and an event identifier. The AF node  131  transmits the subscription request to the NEF node  133  because the AF node  131  and the AMF node  132  may communicate with each other via the NEF node  133 . 
     Action  302 . The NEF node  133  thus receives the subscription request to the UE frequency event from the AF node  131  and transmits the subscription request towards the AMF node  132 . 
     Action  303 . The AMF node  132  receives the subscription request to the UE frequency event from the NEF node  133 . As the AF node now subscribes to the UE frequency, the AMF node  132  then provides information about usage of the first frequency for the UE  120  to the AF node  131 . As the AF node  131  and AMF node  132  communicate via the NEF node  133 , the AMF node  132  transmits, towards the NEF node  133 , information about usage of the first frequency for the UE  120 . 
     Action  304 . The NEF node  133  receives the information about usage of the first frequency for the UE  120  from the AMF node  132  and transmits the received information about usage of the first frequency for the UE  120  towards the AF node  131 . 
     Action  305 . As the AF node  131  now has obtained the information about usage of the first frequency for the UE  120 , the AF node  131  thus knows what frequency the UE  120  is using. The AF node then applies a first congestion mechanism based on the obtained information about usage of the first frequency. 
     Action  306 . The AMF node  132  then detects that usage of the frequency of the UE  120  changes. Such changes may e.g. be due to availability and/or unavailability of frequencies or due to that certain applications in the UE  120  may need higher frequencies to have more bandwidth. The frequency used by the UE  120  is typically controlled by a radio scheduling function in the network which may change the UE&#39;s frequency usage for whatever reason. 
     Action  307 . When the AMF node  133  has detected that the frequency of the UE  120  has changed, the AMF node  132  provides the changed UE frequency, e.g. the information about usage of a second frequency for the UE to the AF node  131 . Again, as explained above, as the AMF node  132  and the AF node  131  communicate via the NEF node  133 , the AMF node transmits the information about usage of the second frequency for the UE  120  towards the NEF node  133 . 
     Action  308 . The NEF node  133  receives the information about usage of the second frequency for the UE  120  from the AMF node  132  and then transmits this information to the AF node  131 . 
     Action  309 . The AF node  131  now has obtained information about usage of the second frequency for the UE  120  from the AMF node  132  and thus applies a second congestion mechanism in response to the obtained information. 
     Example embodiments of a method performed by the AF node  131  for handling the data session for the UE  120  in the communication network  100  will now be described with reference to a flowchart depicted in  FIG.  4   . The method comprises the following actions, which actions may be taken in any suitable order. 
     Action  401   
     The AF node  131  obtains information about usage of the first frequency for the UE  120  from the AMF node  132 . The AF node  131  and the AMF node  132  may communicate via the NEF node  133 . The obtaining information about usage of the first frequency may comprise transmitting, towards the NEF node  133 , the subscription request to the UE frequency event, and receiving, from the NEF node  133 , information about usage of the first frequency for the UE  120 . The subscription request may comprise the UE identifier and the event identifier. This action corresponds to the above actions  301  and  304 . 
     Action  402   
     The AF node  131  then applies the first congestion mechanism based on the obtained information about usage of the first frequency. This action corresponds to the above action  305 . 
     Action  403   
     The AF node  131  obtains information about usage of the second frequency for the UE  120  from the AMF node  132 . The obtaining information about usage of the second frequency for the UE  120  may comprise receiving, from the NEF node  133 , information about usage of the second frequency for the UE  120 . This action corresponds to the above action  308 . 
     Action  404   
     The AF node  131  then applies the second congestion mechanism in response to the obtained information about usage of the second frequency. This action corresponds to the above action  309 . 
     Example embodiments of a method performed by the AMF node  132  for handling the data session for the UE  120  in the communication network  100  will now be described with reference to a flowchart depicted in  FIG.  5   . The method comprises the following actions, which actions may be taken in any suitable order. 
     Action  501   
     The AMF node  132  may receive, from the NEF node  133 , a subscription request to a UE frequency event. The subscription request may comprise the UE identifier and the event identifier. This action corresponds to the above action  302 . 
     Action  502   
     The AMF node  132  provides information about usage of the first frequency for the UE  120  to the AF node  131 . As mentioned before, the AF node  131  and the AMF node  132  may communicate via the NEF node  133 . The providing information about usage of the first frequency may comprise transmitting, towards the NEF node  133 , information about usage of the first frequency for the UE  120 . This action corresponds to the above action  303  and  304 . 
     Action  503   
     The AMF node  132  detects that usage of the frequency of the UE  120  changes. This action corresponds to the action  306 . 
     Action  504   
     The AMF node  132  provides information about usage of the second frequency for the UE  120  to the AF node  131 . The providing information about usage of the second frequency may comprise transmitting, towards the NEF node  133 , information about usage of the second frequency for the UE  120 . This action corresponds to the above action  307  and  308 . 
     Embodiments herein such as mentioned above will now be further described and exemplified. The text below is applicable to and may be combined with any suitable embodiment described above. 
     An, example of a method according to some embodiments, is shown in the combined signalling scheme and flowchart of  FIG.  6   .  FIG.  6    illustrates the example where the AF node  131  subscribes to the UE frequency event and comprises the steps 1-10 where the order of the steps may vary in different implementations: 
     Preconditions: The UE  120  has a PDU session already established. A single UE  120  is shown for the sake of simplicity. 
     Step 1. The AF node  131  which may be a content provider such as e.g. Vimeo, may subscribe to the UE frequency. In order to do so, it triggers a Nnef_AnalyticsExposure Subscribe (HTTP POST) message including the following information:
         The identifier of the (new) Analytic of interest, e.g. Analytic-ID=UE frequency.   The identifier of the UE  120 , e.g. UE-ID. The subscription may relate to a single UE, a group of UEs.       

     The AF node  131  subscribes to changes of the frequency of the UE  120 , e.g. the subscriber&#39;s frequency. The AF node  131  has different congestion schemes according to the frequency of the UE  120 . One congestion window for FR1 and for FR2, as was shown in Table 1 above. 
     Step 2. The NEF node  133  may answer the AF node  131  with a Nnef_AnalyticsExposure 200 OK message. 
     Step 3-4. Optionally, in case the NEF node  132  does not know the AMF node  132  to which the UE  120  is attached, the NEF node  133  can request for the AMF node  131  from a Unified Data Repository (UDR). The UDR is a converged repository of subscriber information and can be used to service a number of network functions. The UDR may then respond with the AMF node  132 . 
     Step 5. The NEF node may subscribe to changes of frequency in the AMF node  132  using the Namf_EventExposureService with an event called Frequency. The AMF node  132  may provide a new event to be provided by Namf_EventExposure Service. 
     The definition of this event is the following: 
     Event: Frequency 
     A Network Function (NF) may subscribe to the event Frequency to receive the event report of a UE or group of UEs when an AMF detects that a target UE has changed the frequency, by default the so-called arfcnDL parameter in accordance with 3GPP TS 28.541. 
     UE Type: One UE, Group of UEs. 
     Report Type: One-Time Report, Continuous Report 
     Input: UE ID(s). Optionally: NG-RAN node, or RRU, N3IWF, UE-IP 
     Notification: UE-ID, frequency band e.g. FR1, FR2 or values provided by arfcnDL Parameter. Optionally the recommended congestion control mechanism with some parameters may be provided. 
     Step 6. The AMF node  132  may answer to the NEF node  133  e.g. with frequency band FR1, FR2 or values provided by arfcnDL. 
     Step 7. The AMF node  132  notifies the frequency of the UE  120 . In this example in  FIG.  6    the frequency of the UE 120  is FR1, not mmWave. 
     Step 8. The NEF node  133  may notify the AF node  132  of the UE identifier, e.g. UE-ID, and the frequency band of the UE  120 . Optionally, the NEF node  133  may provide a recommended congestion window with some parameters. In this particular case, the congestion mechanism TCP cubic with an initial congestion window=10. The AF may apply the TCP Cubic congestion mechanism due to that the UE  120  is using this frequency. 
     Step 9. The UE  120  enters in a zone where high frequency, such as mmWave, is provided or the radio network provides a higher frequency, so the UE  120  changes from FR1 to FR 2 frequency. The AMF node  132  notifies to NEF node  133  of the new frequency of the UE  120 . In this example it is FR2. 
     Step 10. The NEF node  133  may notify the AF node  131  of the frequency band of the UE  120 . Optionally, the NEF node  133  can provide the best recommended congestion window with some parameters. In this particular case, the congestion mechanism Yeah with an initial congestion window=r0. The AF node  131  may apply, e.g. the congestion mechanism Yeah, due to that the UE  120  is using this frequency band. The Yeah congestion mechanism is used as it may be better in mmWave scenarios. 
     The AMF node  132  may send information about those events to the UPF node  134  so that the UPF node can apply corresponding optimizations based on this information. 
     Another example according to some embodiments is shown in the combined signalling scheme and flowchart in  FIGS.  7 B and  7 A , where  FIG.  7 B  is a continuation of  FIG.  7 A .  FIGS.  7 A and  7 B  concern a case where the UPF node  134  subscribes to a UE frequency event and comprises the steps as described below.  FIGS.  7 A and  7 B  comprise the steps 1-17 where the order of the steps may vary in different implementations. 
     Precondition: An optimization information storage/retrieval policy may be pre-configured in the UDR as subscriber policy data, e.g. UE  120  policy data. This example shows per subscriber policies, but this flow information storage policy may also be applied to a certain application, to a group of UEs, e.g. subscribers, to a certain network slice or globally e.g. on a per node or network basis. In this example the behaviour in case handover occurs in a traffic optimization, is shown. 
     Steps 1-2. At a Packet Forwarding Control Protocol (PFCP) Association procedure between UPF and SMF entities, it is proposed to extend the existing mechanism to report UPF capabilities with a new capability Frequency Information for Optimization (FIOP), see Table 2 below in bold). 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 UP Function Features 
               
            
           
           
               
               
            
               
                 Feature 
                   
               
            
           
           
               
               
               
               
            
               
                 Octet/ 
                   
                   
                   
               
               
                 Bit 
                 Feature 
                 Interface 
                 Description 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 5/1 
                 BUCP 
                 Sxa, N4 
                 Downlink Data Buffering in CP function is 
               
               
                   
                   
                   
                 supported by the UP function. 
               
               
                 5/2 
                 DDND 
                 Sxa, N4 
                 The buffering parameter ‘Downlink Data 
               
               
                   
                   
                   
                 Notification Delay’ is supported by the UP 
               
               
                   
                   
                   
                 function. 
               
               
                 5/3 
                 DLBD 
                 Sxa, N4 
                 The buffering parameter ‘DL Buffering 
               
               
                   
                   
                   
                 Duration’ is supported by the UP function. 
               
               
                 5/4 
                 TRST 
                 Sxb, Sxc,  
                 Traffic Steering is supported by the UP 
               
               
                   
                   
                 N4 
                 function. 
               
               
                 5/5 
                 FTUP 
                 Sxa, Sxb,  
                 F-TEID allocation/release in the UP 
               
               
                   
                   
                 N4 
                 function is supported by the UP function. 
               
               
                 5/6 
                 PFDM 
                 Sxb, Sxc,  
                 The PFD Management procedure is 
               
               
                   
                   
                 N4 
                 supported by the UP function. 
               
               
                 5/7 
                 HEEU 
                 Sxb, Sxc,  
                 Header Enrichment of Uplink traffic is 
               
               
                   
                   
                 N4 
                 supported by the UP function. 
               
               
                 5/8 
                 TREU 
                 Sxb, Sxc,  
                 Traffic Redirection Enforcement in the UP 
               
               
                   
                   
                 N4 
                 function is supported by the UP function. 
               
               
                 6/1 
                 EMPU 
                 Sxa, Sxb,  
                 Sending of End Marker packets supported 
               
               
                   
                   
                 N4 
                 by the UP function. 
               
               
                 6/2 
                 PDIU 
                 Sxa, Sxb,  
                 Support of PDI optimised signalling in UP 
               
               
                   
                   
                 Sxc, N4 
                 function (see clause 5.2.1A.2). 
               
               
                 6/3 
                 UDBC 
                 Sxb, Sxc,  N4 
                 Support of UL/DL Buffering Control 
               
               
                 6/4 
                 QUOAC 
                 Sxb, Sxc,  
                 The UP function supports being 
               
               
                   
                   
                 N4 
                 provisioned with the Quota Action to apply 
               
               
                   
                   
                   
                 when reaching quotas. 
               
               
                 6/5 
                 TRACE 
                 Sxa, Sxb,  
                 The UP function supports Trace (see 
               
               
                   
                   
                 Sxc, N4 
                 clause 5.15). 
               
               
                 6/6 
                 FRRT 
                 Sxb, N4 
                 The UP function supports Framed Routing 
               
               
                   
                   
                   
                 (see IETF RFC 2865 [37] and 
               
               
                   
                   
                   
                 IETF RFC 3162 [38]). 
               
               
                 6/7 
                 PFDE 
                 Sxb, N4 
                 The UP function supports a PFD Contents 
               
               
                   
                   
                   
                 including a property with multiple values. 
               
               
                 6/8 
                 EPFAR 
                 Sxa, Sxb,  
                 The UP function supports the Enhanced 
               
               
                   
                   
                 Sxc, N4 
                 PFCP Association Release feature (see 
               
               
                   
                   
                   
                 clause 5.18). 
               
               
                 7/1 
                 DPDRA 
                 Sxb, Sxc,  
                 The UP function supports Deferred PDR 
               
               
                   
                   
                 N4 
                 Activation or Deactivation. 
               
               
                 7/2 
                 ADPDP 
                 Sxa, Sxb,  
                 The UP function supports the Activation 
               
               
                   
                   
                 Sxc, N4 
                 and Deactivation of Pre-defined PDRs 
               
               
                   
                   
                   
                 (see clause 5.19). 
               
               
                 7/3 
                 UEIP 
                 N4 
                 The UPF supports allocating UE IP 
               
               
                   
                   
                   
                 addresses or prefixes (see clause 5.21). 
               
               
                 7/4 
                 SSET 
                 N4 
                 UPF support of PFCP sessions 
               
               
                   
                   
                   
                 successively controlled by different SMFs 
               
               
                   
                   
                   
                 of a same SMF Set (see clause 5.22). 
               
               
                 7/5 
                 MNOP 
                 Sxa, Sxb,  
                 UPF supports measurement of number of 
               
               
                   
                   
                 Sxc, N4 
                 packets which is instructed with the flag 
               
               
                   
                   
                   
                 ‘Measurement of Number of Packets’ in a 
               
               
                   
                   
                   
                 URR. See also 5.2.2.2.1. 
               
               
                 7/6 
                 MTE 
                 N4 
                 UPF supports multiple instances of Traffic 
               
               
                   
                   
                   
                 Endpoint IDs in a PDI. 
               
               
                 7/7 
                 BUNDL 
                 Sxa, Sxb,  
                 PFCP messages bunding (see clause 6.5) 
               
               
                   
                   
                 Sxc, N4 
                 is supported by the UP function. 
               
               
                 7/8 
                 GCOM 
                 N4 
                 UPF support of 5G VN Group 
               
               
                   
                   
                   
                 Communication. (See clause 5.23) 
               
               
                 8/1 
                 MPAS 
                 N4 
                 UPF support for multiple PFCP 
               
               
                   
                   
                   
                 associations to the SMFs in an SMF set 
               
               
                   
                   
                   
                 (see clause 5.22.3). 
               
               
                 8/2 
                 RTTL 
                 N4 
                 The UP function supports redundant 
               
               
                   
                   
                   
                 transmission at transport layer. 
               
               
                 8/3 
                 VTIME 
                 Sxb,N4 
                 UPF support of quota validity time feature. 
               
               
                 8/4 
                 FIOP 
                 Sxb, Sxc,  
                 Frequency Information Optimization. 
               
               
                   
                   
                 N4 
                 UPF gets information of frequency and 
               
               
                   
                   
                   
                 optimizes flows or not considering 
               
               
                   
                   
                   
                 frequency of the subscriber. 
               
               
                   
               
            
           
         
       
     
     Step 3. The UE  120  may trigger a PDU session establishment, by means of sending a PDU Session Establishment Request to the AMF node  132 . 
     Step 4. The AMF node  132  may select an SMF to manage the PDU session, the SMF selection function in the AMF node  132  selects an SMF instance based on the available SMF instances obtained from NRF or on the configured SMF information in the AMF node  132 , and triggers a Nsmf PDU Session Create message. 
     Step 5. The SMF may trigger an Npcf_SMPolicyControl_Create Request message to retrieve Session Management (SM) policies for the user PDU session. 
     Step 6) The PCF triggers a so-called Nudr_Query Request message, including a subscriber identifier, e.g. UE identifier, to retrieve the policy data for the UE&#39;s  120  PDU session. 
     Step 7. The UDR answers with a Nudr_Query Response message, including the Subscriber Policy Data, which includes a new handover information for optimization policies. As an example, a binary flag as handover information policies may be assumed:
         TRUE: Track frequency for optimization   FALSE: No consider frequency       

     This value may be extended with more granular information in case it is needed to check frequency at other levels such as Radio Resource Unit (RRU) set of NG-RAN nodes, etc. 
     In  FIGS.  7 A and  7 B  it may be assumed that optimization will be performed at the UPF node  134 . This example also assumes the optimization with frequency information policy applied on a per subscriber&#39;s PDU session basis. It is also possible to configure different optimization with frequency information policies for each application. 
     Step 8. The PCF may generate the corresponding PCC rule/s based on Subscriber Policy Data, and may also include the optimization with handover information (TRUE), which in this example applies on a per PDU session basis. 
     Step 9. The SMF may select the UPF and triggers a PFCP Session Establishment procedure towards the UPF to provision Packet Detection Rules (PDRs), and the corresponding enforcement actions: QoS Enforcement Rule (QER) Forwarding Action Rules (FARs), Usage Reporting Rules (URRs), etc., for the PDU session. Specifically, the SMF may provision the handover information. In order to do this, it is proposed to extend the PFCP protocol by adding a new “Frequency Information” IE at “PFCP Session Establishment/Modification Request”, as shown in Table 3 and Table 4 below in bold: 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Create QER IE within PFCP Session Establishment Request 
               
            
           
           
               
               
            
               
                   
                 Octet 1 and 2 
               
               
                   
                 Create QER IE Type = 7 (decimal) 
               
               
                   
                 Octets 3 and 4 
               
               
                   
                 Length = n 
               
            
           
           
               
               
               
               
               
            
               
                 Information 
                   
                   
                 Appl. 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 elements 
                 P 
                 Condition/Comment 
                 SXa 
                 SXb 
                 SXc 
                 N4 
                 IE Type 
               
               
                   
               
               
                 QER ID 
                 M 
                 This IE shall uniquely identify the QER among 
                 — 
                 X 
                 X 
                 X 
                 QER ID 
               
               
                   
                   
                 all the QER configured for that PFCP session 
                   
                   
                   
                   
                   
               
               
                 QER 
                 C 
                 This IE shall be present if the UP function is 
                 — 
                 X 
                 — 
                 X 
                 QER 
               
               
                 Correlation ID 
                   
                 required to correlate the QERs of several 
                   
                   
                   
                   
                 Correlation 
               
               
                   
                   
                 PFCP sessions, for APN-AMBR enforcement 
                   
                   
                   
                   
                 ID 
               
               
                   
                   
                 of multiple UE’s PDN connections to the same 
                   
                   
                   
                   
                   
               
               
                   
                   
                 APN. 
                   
                   
                   
                   
                   
               
               
                 Gate Status 
                 M 
                 This IE shall indicate whether the packets are 
                 — 
                 X 
                 X 
                 X 
                 Gate Status 
               
               
                   
                   
                 allowed to be forwarded (the gate is open) or 
                   
                   
                   
                   
                   
               
               
                   
                   
                 shall be discarded (the gate is closed) in the 
                   
                   
                   
                   
                   
               
               
                   
                   
                 uplink and/or downlink directions. 
                   
                   
                   
                   
                   
               
               
                 Maximum 
                 C 
                 This IE shall be present if an MBR enforcement 
                 — 
                 X 
                 X 
                 X 
                 MBR 
               
               
                 Bitrate 
                   
                 action shall be applied to packets matching this 
                   
                   
                   
                   
                   
               
               
                   
                   
                 PDR. When present, this IE shall indicate the 
                   
                   
                   
                   
                   
               
               
                   
                   
                 uplink and/or downlink maximum bit rate to be 
                   
                   
                   
                   
                   
               
               
                   
                   
                 enforced for packets matching the PDR. 
                   
                   
                   
                   
                   
               
               
                   
                   
                 For EPC, this IE may be set to the value of: 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the APN-AMBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of the non- 
                   
                   
                   
                   
                   
               
               
                   
                   
                 GBR bearers of a PDN connection; 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the TDF session MBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of a TDF 
                   
                   
                   
                   
                   
               
               
                   
                   
                 session; 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the bearer MBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of a bearer; 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the SDF MBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of a SDF. 
                   
                   
                   
                   
                   
               
               
                   
                   
                 For 5GC, this IE may be set to the value of: 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the Session-AMBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of the non- 
                   
                   
                   
                   
                   
               
               
                   
                   
                 GBR QoS flows of a PDU session; 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the QoS Flow MBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of a QoS 
                   
                   
                   
                   
                   
               
               
                   
                   
                 Flow; 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the SDF MBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of a SDF. 
                   
                   
                   
                   
                   
               
               
                 Guaranteed 
                 C 
                 This IE shall be present if a GBR has been 
                 — 
                 X 
                 X 
                 X 
                 GBR 
               
               
                 Bitrate 
                   
                 authorized to packets matching this PDR. 
                   
                   
                   
                   
                   
               
               
                   
                   
                 When present, this IE shall indicate the 
                   
                   
                   
                   
                   
               
               
                   
                   
                 authorized uplink and/or downlink guaranteed 
                   
                   
                   
                   
                   
               
               
                   
                   
                 bit rate. 
                   
                   
                   
                   
                   
               
               
                   
                   
                 This IE may be set to the value of: 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the aggregate GBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of a GBR 
                   
                   
                   
                   
                   
               
               
                   
                   
                 bearer; 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the QoS Flow GBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of a QoS 
                   
                   
                   
                   
                   
               
               
                   
                   
                 Flow (for 5GC); 
                   
                   
                   
                   
                   
               
               
                   
                   
                 the SDF GBR, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of a SDF. 
                   
                   
                   
                   
                   
               
               
                 Packet Rate 
                 C 
                 This IE shall be present if a Packet Rate 
                 — 
                 X 
                 — 
                 — 
                 Packet Rate 
               
               
                   
                   
                 enforcement action (in terms of number of 
                   
                   
                   
                   
                   
               
               
                   
                   
                 packets per time interval) shall be applied to 
                   
                   
                   
                   
                   
               
               
                   
                   
                 packets matching this PDR. 
                   
                   
                   
                   
                   
               
               
                   
                   
                 When present, this IE shall indicate the uplink 
                   
                   
                   
                   
                   
               
               
                   
                   
                 and/or downlink maximum packet rate to be 
                   
                   
                   
                   
                   
               
               
                   
                   
                 enforced for packets matching the PDR. 
                   
                   
                   
                   
                   
               
               
                   
                   
                 This IE may be set to the value of: 
                   
                   
                   
                   
                   
               
               
                   
                   
                 downlink packet rate for Serving PLMN 
                   
                   
                   
                   
                   
               
               
                   
                   
                 Rate Control, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all PDRs of the UE 
                   
                   
                   
                   
                   
               
               
                   
                   
                 belonging to the PDN connection using 
                   
                   
                   
                   
                   
               
               
                   
                   
                 CloT EPS Optimizations as described in 
                   
                   
                   
                   
                   
               
               
                   
                   
                 3 GPP TS 23.401 [2]); 
                   
                   
                   
                   
                   
               
               
                   
                   
                 uplink and/or downlink packet rate for 
                   
                   
                   
                   
                   
               
               
                   
                   
                 APN Rate Control, for a QER that is 
                   
                   
                   
                   
                   
               
               
                   
                   
                 referenced by all the PDRs of the UE 
                   
                   
                   
                   
                   
               
               
                   
                   
                 belonging to PDN connections to the 
                   
                   
                   
                   
                   
               
               
                   
                   
                 same APN using CioT EPS 
                   
                   
                   
                   
                   
               
               
                   
                   
                 Optimizations as described in 
                   
                   
                   
                   
                   
               
               
                   
                   
                 3 GPP TS 23.401 [2]). 
                   
                   
                   
                   
                   
               
               
                 DL Flow Level 
                 C 
                 This IE shall be set if the UP function is 
                 — 
                 X 
                 X 
                 — 
                 DL Flow 
               
               
                 Marking 
                   
                 required to mark the packets for QoS 
                   
                   
                   
                   
                 Level 
               
               
                   
                   
                 purposes: 
                   
                   
                   
                   
                 Marking 
               
               
                   
                   
                 by the TDF-C, for DL flow level marking 
                   
                   
                   
                   
                   
               
               
                   
                   
                 for application indication (see clause 5.4.5); 
                   
                   
                   
                   
                   
               
               
                   
                   
                 by the PGW-C, for setting the GTP-U 
                   
                   
                   
                   
                   
               
               
                   
                   
                 Service Class Indicator extension 
                   
                   
                   
                   
                   
               
               
                   
                   
                 header for service indication towards 
                   
                   
                   
                   
                   
               
               
                   
                   
                 GERAN (see clause 5.4.12). 
                   
                   
                   
                   
                   
               
               
                 QoS flow 
                 C 
                 This IE shall be present if the QoS flow 
                 — 
                 — 
                 — 
                 X 
                 QFI 
               
               
                 identifier 
                   
                 identifier shall be inserted by the UPF. 
                   
                   
                   
                   
                   
               
               
                 Reflective QoS 
                 C 
                 This IE shall be present if the UP function is 
                 — 
                 — 
                 — 
                 X 
                 RQI 
               
               
                   
                   
                 required to insert a Reflective QoS Identifier to 
                   
                   
                   
                   
                   
               
               
                   
                   
                 request reflective QoS for uplink traffic. 
                   
                   
                   
                   
                   
               
               
                 Paging Policy 
                 C 
                 This IE shall be present if the UPF is required 
                 — 
                 — 
                 — 
                 X 
                 Paging Policy 
               
               
                 Indicator 
                   
                 to set the Paging Policy Indicator (PPI) in 
                   
                   
                   
                   
                 Indicator 
               
               
                   
                   
                 outgoing packets (see clause 5.4.3.2 of 
                   
                   
                   
                   
                   
               
               
                   
                   
                 3 GPP TS 23.501 [28]). 
                   
                   
                   
                   
                   
               
               
                   
                   
                 When present, it shall be set to the PPI value 
                   
                   
                   
                   
                   
               
               
                   
                   
                 to set. 
                   
                   
                   
                   
                   
               
               
                 Averaging 
                 O 
                 This IE may be present if the UP function is 
                 — 
                 — 
                 — 
                 X 
                 Averaging 
               
               
                 Window 
                   
                 required to use a different Averaging window 
                   
                   
                   
                   
                 Window 
               
               
                   
                   
                 than the default one. (NOTE) 
                   
                   
                   
                   
                   
               
               
                 Frequency 
                 O 
                 This IE may be present if the UPF function 
                 — 
                 — 
                 — 
                 X 
                 Frequency 
               
               
                 Information 
                   
                 is required to modify its behaviour in case 
                   
                   
                   
                   
                 Information 
               
               
                   
                   
                 of frequency modification 
               
               
                   
               
               
                 NOTE: 
               
               
                 As 5Q is not signalled over N4, one default averaging window shall be pre-configured in the UPF. 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 Frequency Information IE 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 Octet 1 and 2 
                 Usage Report IE Type = 80 (decimal) 
               
               
                 Octets 3 and 4 
                 Length = n 
               
            
           
           
               
               
               
               
            
               
                 Information 
                 P 
                 Condition/Comment 
                 IE Type 
               
               
                 elements 
                   
                   
                   
               
               
                 Frequency 
                 C 
                 The name of the Frequency 
                 Frequency 
               
               
                 Information 
                   
                 Information profile. 
                 Information 
               
               
                 Profile 
                   
                   
                 Profile 
               
               
                   
               
            
           
         
       
     
     In this example:
         Frequency Information Profile=FR1       

     There may be similar attributes for a session modification message. 
     Step 11. The SMF answers to the AMF node  132  request. 
     Step 12. The UE  120  has a PDU session established. 
     Steps 13-14. Optionally, in case the UPF node  134  does not know the AMF node  132  to which the UE  120  is attached, the UPF node  134  may ask for the AMF node  132  from the UDR. The UDR may then answer with the AMF node  132 . 
     Step 15. The UPF node  134  may subscribe to the Namf_EventExposure Service. In this case, a new event is exposed with this service. It is the handover of cells performed by the UE  120 . The definition of this event is the following: 
     The AMF node  132  may provide a new event to be provided by Namf_EventExposure Service. 
     Event: Frequency 
     An NF subscribes to this event to receive the event report of a UE or group of UEs when the AMF node  132  detects that a target UE has changed the frequency, by default the arfcnDL parameter, as described in 3GPP TS 28.541. 
     UE Type: One UE, Group of UEs. 
     Report Type: One-Time Report, Continuous Report. 
     Input: UE ID(s). Optionally: NG-RAN node, or RRU, N3IWF, UE-IP. 
     Notification; UE-ID, Frequency (FR1, FR2 or values provided by arfcnDL Parameter) 
     Step 16. The AMF node  132  may confirm that the subscription is correct. 
     Step 17. The AMF may notify that the UE  120  has changed the frequency, using the Namf_EventExposure Service. The UPF node  134  may adapt its optimization to this UE  120  based on this information, such as e.g. modifying its buffer size or changing parameters in the AQM algorithm. 
       FIG.  8    is a block diagram depicting the AF node  131  for handling the data session for the UE  120  in the communication network  100 , according to embodiments herein. 
     The AF node  131  may comprise processing circuitry  801 , e.g. one or more processors, configured to perform the methods herein. 
     The AF node  131  may comprise an obtaining unit  802 . The AF node  131 , the processing circuitry  801 , and/or the obtaining unit  802  is configured to obtain information about usage of the first frequency for the UE  120  from the AMF node  132 . 
     The AF node  131  and the AMF node  132  may communicate via the NEF node  133 . 
     The obtaining information about usage of the first frequency may be adapted to comprise to transmit, towards the NEF node  133 , the subscription request to the UE frequency event, wherein the subscription request comprises the UE identifier and the event identifier, and to receive, from the NEF node  133 , information about usage of the first frequency for the UE  120 . 
     The AF node  131 , the processing circuitry  801 , and/or the obtaining unit  802  is configured to obtain information about usage of the second frequency for the UE  120  from the AMF node  132 . The obtaining information about usage of the second frequency for the UE  120  may be adapted to comprise to receive, from the NEF node  133 , information about usage of the second frequency for the UE  120 . 
     The AF node  131  may comprise an applying unit  803 . The AF node  131 , the processing circuitry  801 , and/or the applying unit  803  is configured to apply the first congestion mechanism based on the obtained information about usage of the first frequency of the UE  120 . 
     The AF node  131 , the processing circuitry  801 , and/or the applying unit  803  is configured to apply the second congestion mechanism in response to the obtained information about usage of the second frequency of the UE  120 . 
     The AF node  131  further comprises a memory  805 . The memory  805  comprises one or more units to be used to store data on, such as frequency information, UE identifier and event identifier information, input/output data, metadata, etc. and applications to perform the methods disclosed herein when being executed, and similar. The AF node  131  may further comprise a communication interface comprising e.g. one or more antenna or antenna elements. 
     The methods according to the embodiments described herein for the AF node  131  are respectively implemented by means of e.g. a computer program product  806  or a computer program, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the AF node  131 . The computer program product  806  may be stored on a computer-readable storage medium  807 , e.g. a disc, a universal serial bus (USB) stick or similar. The computer-readable storage medium  807 , having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the AF node  131 . In some embodiments, the computer-readable storage medium may be a transitory or a non-transitory computer-readable storage medium. 
       FIG.  9    is a block diagram depicting the AMF node  132  for handling the data session for the UE  120  in the communication network  100 , according to embodiments herein. 
     The AMF node  132  may comprise processing circuitry  901 , e.g. one or more processors, configured to perform the methods herein. 
     The AMF node  132  may comprise a receiving unit  902 . The AMF node  132 , the processing circuitry  901 , and/or the receiving unit  902  may be configured to receive from the NEF node  133 , the subscription request to the UE frequency event, wherein the subscription request comprises the UE identifier and the event identifier. 
     The AMF node  132  may comprise a providing unit  903 . The AMF node  132 , the processing circuitry  901 , and/or the providing unit  903  is configured to provide information about usage of the first frequency for the UE to the AF node  131 . 
     The AF node  131  and the AMF node  132  may communicate via the NEF node  133 . 
     The providing information about usage of the first frequency may be adapted to comprise to transmit, towards the NEF node  133 , information about usage of the first frequency. 
     The AMF node  132 , the processing circuitry  901 , and/or the providing unit  903  is configured to provide information about usage of the second frequency for the UE  120  to the AF node  131 . The providing information about usage of the second frequency may be adapted to comprise to transmit, towards the NEF node  133 , information about usage of the second frequency. 
     The AMF node  132  may comprise a detecting unit  904 . The AMF node  132 , the processing circuitry  901 , and/or the detecting unit  904  is configured to detect that usage of the frequency of the UE  120  changes. 
     The AMF node  132  further comprises a memory  905 . The memory  905  comprises one or more units to be used to store data on, such as frequency information, UE identifier and event identifier information, input/output data, metadata, etc. and applications to perform the methods disclosed herein when being executed, and similar. The AMF node  132  may further comprise a communication interface comprising e.g. one or more antenna or antenna elements. 
     The methods according to the embodiments described herein for the AMF node  132  are respectively implemented by means of e.g. a computer program product  906  or a computer program, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the AMF node  132 . The computer program product  906  may be stored on a computer-readable storage medium  907 , e.g. a disc, a universal serial bus (USB) stick or similar. The computer-readable storage medium  907 , having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the AMF node  132 . In some embodiments, the computer-readable storage medium may be a transitory or a non-transitory computer-readable storage medium. 
     The system for handling a data session for the UE  120  in the communication network  100  is illustrated in  FIG.  10   . The system may comprise the AF node  131  and the AMF node  132 , shown in  FIG.  8    and  FIG.  9    respectively. The system may also comprise the UPF node  134 . The UPF node  134  may comprise processing circuitry  1001 , e.g. one or more processors, configured to perform the methods herein. 
     The UPF node  134  may comprise a transmitting unit  1002 . The UPF node  134 , the processing circuitry  1001 , and/or the transmitting unit  1002  may be configured to transmit, towards the AMF node  132 , a subscription request to a UE frequency event, wherein the subscription request comprises a UE identifier and an event identifier. 
     The UPF node  134  may comprise an obtaining unit  1003 . The UPF node  134 , the processing circuitry  1001 , and/or the obtaining unit  1003  may be configured to obtain, from the AMF node  132 , information about usage of the frequency for the UE  120 . 
     The UPF node  134  may comprise an optimizing unit  1004 . The UPF node  134 , the processing circuitry  1001 , and/or the optimizing unit  1004  may be configured to optimize UE traffic in accordance with the received information about usage of the frequency for the UE  120 . 
     In some embodiments a more general term “network node” is used and it can correspond to any type of radio-network node or any network node, which communicates with a wireless device and/or with another network node. Examples of network nodes are gNodeB, eNodeB, NodeB, MeNB, SeNB, a network node belonging to Master cell group (MCG) or Secondary cell group (SCG), base station (BS), multi-standard radio (MSR) radio node such as MSR BS, eNodeB, network controller, radio-network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), access point (AP), transmission points, transmission nodes, Remote radio Unit (RRU), Remote Radio Head (RRH), nodes in distributed antenna system (DAS), etc. 
     In some embodiments the non-limiting term wireless device or user equipment (UE) is used and it refers to any type of wireless device communicating with a network node and/or with another wireless device in a cellular or mobile communication system. Examples of UE are target device, device to device (D2D) UE, proximity capable UE (aka ProSe UE), machine type UE or UE capable of machine to machine (M2M) communication, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles etc. 
     Embodiments are applicable to any radio access technology (RAT) or multi-RAT systems, where the devices receives and/or transmit signals, e.g. data, such as New Radio (NR), Wi-Fi, Long Term Evolution (LTE), LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. 
     As will be readily understood by those familiar with communications design, that functions means or circuits may be implemented using digital logic and/or one or more microcontrollers, microprocessors, or other digital hardware. In some embodiments, several or all of the various functions may be implemented together, such as in a single application-specific integrated circuit (ASIC), or in two or more separate devices with appropriate hardware and/or software interfaces between them. Several of the functions may be implemented on a processor shared with other functional components of a UE or network node, for example. 
     Alternatively, several of the functional elements of the processing units discussed may be provided through the use of dedicated hardware, while others are provided with hardware for executing software, in association with the appropriate software or firmware. Thus, the term “processor” or “controller” as used herein does not exclusively refer to hardware capable of executing software and may implicitly include, without limitation, digital signal processor (DSP) hardware and/or program or application data. Other hardware, conventional and/or custom, may also be included. Designers of communications devices will appreciate the cost, performance, and maintenance trade-offs inherent in these design choices. 
     It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and apparatus taught herein. As such, the apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited only by the following claims and their legal equivalents. 
     Further Extensions and Variations 
     With reference to  FIG.  11   , in accordance with an embodiment, a communication system includes a telecommunication network  3210  such as the wireless communications network  100 , e.g. a NR network, such as a 3GPP-type cellular network, which comprises an access network  3211 , such as a radio access network, and a core network  3214 . The access network  3211  comprises a plurality of base stations  3212   a ,  3212   b ,  3212   c , such as the radio network node  110 , access nodes, AP STAs NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area  3213   a ,  3213   b ,  3213   c . Each base station  3212   a ,  3212   b ,  3212   c  is connectable to the core network  3214  over a wired or wireless connection  3215 . A first user equipment (UE) e.g. the wireless devices  120  such as a Non-AP STA  3291  located in coverage area  3213   c  is configured to wirelessly connect to, or be paged by, the corresponding base station  3212   c . A second UE  3292  e.g. the first or second radio node  110 ,  120  or such as a Non-AP STA in coverage area  3213   a  is wirelessly connectable to the corresponding base station  3212   a . While a plurality of UEs  3291 ,  3292  are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station  3212 . 
     The telecommunication network  3210  is itself connected to a host computer  3230 , which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer  3230  may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections  3221 ,  3222  between the telecommunication network  3210  and the host computer  3230  may extend directly from the core network  3214  to the host computer  3230  or may go via an optional intermediate network  3220 . The intermediate network  3220  may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network  3220 , if any, may be a backbone network or the Internet; in particular, the intermediate network  3220  may comprise two or more sub-networks (not shown). 
     The communication system of  FIG.  11    as a whole enables connectivity between one of the connected UEs  3291 ,  3292  and the host computer  3230 . The connectivity may be described as an over-the-top (OTT) connection  3250 . The host computer  3230  and the connected UEs  3291 ,  3292  are configured to communicate data and/or signalling via the OTT connection  3250 , using the access network  3211 , the core network  3214 , any intermediate network  3220  and possible further infrastructure (not shown) as intermediaries. The OTT connection  3250  may be transparent in the sense that the participating communication devices through which the OTT connection  3250  passes are unaware of routing of uplink and downlink communications. For example, a base station  3212  may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer  3230  to be forwarded (e.g., handed over) to a connected UE  3291 . Similarly, the base station  3212  need not be aware of the future routing of an outgoing uplink communication originating from the UE  3291  towards the host computer  3230 . 
     Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to  FIG.  12   . In a communication system  3300 , a host computer  3310  comprises hardware  3315  including a communication interface  3316  configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system  3300 . The host computer  3310  further comprises processing circuitry  3318 , which may have storage and/or processing capabilities. In particular, the processing circuitry  3318  may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer  3310  further comprises software  3311 , which is stored in or accessible by the host computer  3310  and executable by the processing circuitry  3318 . The software  3311  includes a host application  3312 . The host application  3312  may be operable to provide a service to a remote user, such as a UE  3330  connecting via an OTT connection  3350  terminating at the UE  3330  and the host computer  3310 . In providing the service to the remote user, the host application  3312  may provide user data which is transmitted using the OTT connection  3350 . 
     The communication system  3300  further includes a base station  3320  provided in a telecommunication system and comprising hardware  3325  enabling it to communicate with the host computer  3310  and with the UE  3330 . The hardware  3325  may include a communication interface  3326  for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system  3300 , as well as a radio interface  3327  for setting up and maintaining at least a wireless connection  3370  with a UE  3330  located in a coverage area (not shown in  FIG.  12   ) served by the base station  3320 . The communication interface  3326  may be configured to facilitate a connection  3360  to the host computer  3310 . The connection  3360  may be direct or it may pass through a core network (not shown in  FIG.  12   ) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware  3325  of the base station  3320  further includes processing circuitry  3328 , which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station  3320  further has software  3321  stored internally or accessible via an external connection. 
     The communication system  3300  further includes the UE  3330  already referred to. Its hardware  3335  may include a radio interface  3337  configured to set up and maintain a wireless connection  3370  with a base station serving a coverage area in which the UE  3330  is currently located. The hardware  3335  of the UE  3330  further includes processing circuitry  3338 , which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE  3330  further comprises software  3331 , which is stored in or accessible by the UE  3330  and executable by the processing circuitry  3338 . The software  3331  includes a client application  3332 . The client application  3332  may be operable to provide a service to a human or non-human user via the UE  3330 , with the support of the host computer  3310 . In the host computer  3310 , an executing host application  3312  may communicate with the executing client application  3332  via the OTT connection  3350  terminating at the UE  3330  and the host computer  3310 . In providing the service to the user, the client application  3332  may receive request data from the host application  3312  and provide user data in response to the request data. The OTT connection  3350  may transfer both the request data and the user data. The client application  3332  may interact with the user to generate the user data that it provides. 
     It is noted that the host computer  3310 , base station  3320  and UE  3330  illustrated in  FIG.  12    may be identical to the host computer  3230 , one of the base stations  3212   a ,  3212   b ,  3212   c  and one of the UEs  3291 ,  3292  of  FIG.  11   , respectively. This is to say, the inner workings of these entities may be as shown in  FIG.  12    and independently, the surrounding network topology may be that of  FIG.  11   . 
     In  FIG.  12   , the OTT connection  3350  has been drawn abstractly to illustrate the communication between the host computer  3310  and the use equipment  3330  via the base station  3320 , without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE  3330  or from the service provider operating the host computer  3310 , or both. While the OTT connection  3350  is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network). 
     The wireless connection  3370  between the UE  3330  and the base station  3320  is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE  3330  using the OTT connection  3350 , in which the wireless connection  3370  forms the last segment. More precisely, the teachings of these embodiments may improve the data rate, latency, and power consumption and thereby provide benefits such as user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime. 
     A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection  3350  between the host computer  3310  and UE  3330 , in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection  3350  may be implemented in the software  3311  of the host computer  3310  or in the software  3331  of the UE  3330 , or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection  3350  passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software  3311 ,  3331  may compute or estimate the monitored quantities. The reconfiguring of the OTT connection  3350  may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station  3320 , and it may be unknown or imperceptible to the base station  3320 . Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signalling facilitating the host computer&#39;s  3310  measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software  3311 ,  3331  causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection  3350  while it monitors propagation times, errors etc. 
       FIG.  13    is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to  FIG.  11    and  FIG.  12   . For simplicity of the present disclosure, only drawing references to  FIG.  13    will be included in this section. In a first action  3410  of the method, the host computer provides user data. In an optional subaction  3411  of the first action  3410 , the host computer provides the user data by executing a host application. In a second action  3420 , the host computer initiates a transmission carrying the user data to the UE. In an optional third action  3430 , the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth action  3440 , the UE executes a client application associated with the host application executed by the host computer. 
       FIG.  14    is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to  FIG.  11    and  FIG.  12   . For simplicity of the present disclosure, only drawing references to  FIG.  14    will be included in this section. In a first action  3510  of the method, the host computer provides user data. In an optional subaction (not shown) the host computer provides the user data by executing a host application. In a second action  3520 , the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third action  3530 , the UE receives the user data carried in the transmission. 
       FIG.  15    is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to  FIG.  11    and  FIG.  12   . For simplicity of the present disclosure, only drawing references to  FIG.  15    will be included in this section. In an optional first action  3610  of the method, the UE receives input data provided by the host computer. Additionally or alternatively, in an optional second action  3620 , the UE provides user data. In an optional subaction  3621  of the second action  3620 , the UE provides the user data by executing a client application. In a further optional subaction  3611  of the first action  3610 , the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in an optional third subaction  3630 , transmission of the user data to the host computer. In a fourth action  3640  of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure. 
       FIG.  16    is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to  FIG.  11    and  FIG.  12   . For simplicity of the present disclosure, only drawing references to  FIG.  16    will be included in this section. In an optional first action  3710  of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In an optional second action  3720 , the base station initiates transmission of the received user data to the host computer. In a third action  3730 , the host computer receives the user data carried in the transmission initiated by the base station. 
     When using the word “comprise” or “comprising” it shall be interpreted as non-limiting, i.e. meaning “consist at least of”. 
     The embodiments herein are not limited to the above described preferred embodiments. Various alternatives, modifications and equivalents may be used.