Patent Publication Number: US-2021176808-A1

Title: Method and apparatus for data transmission

Description:
TECHNICAL FIELD 
     The non-limiting and exemplary embodiments of the present disclosure generally relate to the technical field of communications, and specifically to methods, apparatuses and computer program product for data transmission. 
     BACKGROUND 
     This section introduces aspects that may facilitate a better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art. 
     CUPS (Control and User Plane Separation) of EPC (Evolved Packet Core) nodes provides architecture enhancements for the separation of functionality in the EPC. This enables flexible network deployment and operation, by distributed or centralized deployment and the independent scaling between control plane and user plane functions—while not affecting the functionality of the existing nodes subject to this split. 
     SUMMARY 
     Various embodiments of the present disclosure mainly aim at providing methods, apparatuses and computer programs for service discovery. Other features and advantages of embodiments of the present disclosure will also be understood from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of embodiments of the present disclosure. 
     In a first aspect of the disclosure, there is provided a method implemented at a control plane of a packet data network (PDN) gateway (PGW) in a wireless network. The method may comprise determining that an additional user plane of the PGW for a PDN connection needs to be allocated, wherein the PDN connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and an initial user plane of the PGW, and the additional user plane of the PGW is used for connecting with a second data network; selecting the additional user plane of the PGW; sending address information of the additional user plane of the PGW and instruction information to a control plane of the SGW, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In a second aspect of the disclosure, there is provided a method implemented at an additional user plane of a packet data network (PDN) gateway (PGW) in a wireless network. A PDN connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and an initial user plane of the PGW, the additional user plane of the PGW is used for connecting with a second data network. The method may comprise receiving from a control plane of a PGW, address information of the initial user plane of the PGW and instruction information indicating the specified part of uplink data in the PDN connection is forwarded to the second data network and the other part of uplink data in the PDN connection is forwarded to the initial user plane of the PGW; receiving the uplink data from the user plane of the SGW; and forwarding the uplink data based on the instruction information. 
     In a third aspect of the disclosure, there is provided a method implemented at a control plane of a serving gateway (SGW) in a wireless network. A packet data network (PDN) connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of the SGW and an initial user plane of a PDN gateway (PGW) of the wireless network, and the additional user plane of the PGW is used for connecting with a second data network. The method may comprise receiving address information of the additional user plane of the PGW and instruction information from the control plane of the PGW; and sending the address information of the additional user plane of the PGW and instruction information to the user plane of the SGW, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In a fourth aspect of the disclosure, there is provided a method implemented at a user plane of a serving gateway (SGW) in a wireless network. A packet data network (PDN) connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of the SGW and an initial user plane of a PDN gateway (PGW) of a wireless network, the additional user plane of the PGW is used for connecting with a second data network. The method may comprise receiving, from a control plane of the SGW, address information of the additional user plane of the PGW and instruction information; and processing the uplink data in the PDN connection according to the instruction information, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In a fifth aspect of the disclosure, there is provided a method implemented at an initial user plane of a packet data network (PDN) gateway (PGW) in a wireless network. A PDN connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and the initial user plane of the PGW, an additional user plane of the PGW is used for connecting with a second data network, and the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. The method may comprise receiving from a control plane of the PGW, address information of the additional user plane of the PGW and instruction information indicating that the initial user plane of the PGW switches communication from the user plane of the SGW to the additional user plane of the PGW; and switching communication from the user plane of the SGW to the additional user plane of the PGW. 
     In a sixth aspect of the disclosure, there is provided an apparatus for a control plane of a packet data network (PDN) gateway (PGW) in a wireless network. The apparatus may comprise a processor; and a memory coupled to the processor, said memory containing instructions executable by said processor, whereby said apparatus is operative to determine that an additional user plane of the PGW for a PDN connection needs to be allocated, wherein the PDN connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and an initial user plane of the PGW, and the additional user plane of the PGW is used for connecting with a second data network; select the additional user plane of the PGW; and send address information of the additional user plane of the PGW and instruction information to a control plane of the SGW, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In a seventh aspect of the disclosure, there is provided an apparatus for an additional user plane of a packet data network (PDN) gateway (PGW) in a wireless network. A PDN connection may be used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and an initial user plane of the PGW. The additional user plane of the PGW may be used for connecting with a second data network. The apparatus may comprise a processor; and a memory coupled to the processor, said memory containing instructions executable by said processor, whereby said apparatus is operative to receive from a control plane of a PGW, address information of the initial user plane of the PGW and instruction information indicating the specified part of uplink data in the PDN connection is forwarded to the second data network and the other part of uplink data in the PDN connection is forwarded to the initial user plane of the PGW; receive the uplink data from the user plane of the SGW; and forward the uplink data based on the instruction information. 
     In an eighth aspect of the disclosure, there is provided an apparatus for a control plane of a serving gateway (SGW) in a wireless network. A packet data network (PDN) connection may be used by a user equipment (UE) to connect to a first data network through at least a user plane of the SGW and an initial user plane of a PDN gateway (PGW) of the wireless network. The additional user plane of the PGW may be used for connecting with a second data network. The apparatus may comprise a processor; and a memory coupled to the processor, said memory containing instructions executable by said processor, whereby said apparatus is operative to receive address information of the additional user plane of the PGW and instruction information from the control plane of the PGW; and send the address information of the additional user plane of the PGW and instruction information to the user plane of the SGW, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In a ninth aspect of the disclosure, there is provided an apparatus for a user plane of a serving gateway (SGW) in a wireless network. A packet data network (PDN) connection may be used by a user equipment (UE) to connect to a first data network through at least a user plane of the SGW and an initial user plane of a PDN gateway (PGW) of a wireless network. The additional user plane of the PGW may be used for connecting with a second data network. The apparatus may comprise a processor; and a memory coupled to the processor, said memory containing instructions executable by said processor, whereby said apparatus is operative to receive, from a control plane of the SGW, address information of the additional user plane of the PGW and instruction information; and process the uplink data in the PDN connection according to the instruction information, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In a tenth aspect of the disclosure, there is provided an apparatus for an initial plane of a packet data network (PDN) gateway (PGW) in a wireless network. A PDN connection may be used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and the initial user plane of the PGW. The additional user plane of the PGW may be used for connecting with a second data network. The additional user plane of the PGW may implement an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. The apparatus may comprise a processor; and a memory coupled to the processor, said memory containing instructions executable by said processor, whereby said apparatus is operative to receive from a control plane of the PGW, address information of the additional user plane of the PGW and instruction information indicating that the initial user plane of the PGW switches communication from the user plane of the SGW to the additional user plane of the PGW; and switch communication from the user plane of the SGW to the additional user plane of the PGW. 
     In a eleventh aspect of the disclosure, there is provided a computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to the first aspect of the disclosure. 
     In a twelfth aspect of the disclosure, there is provided a computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to the second aspect of the disclosure. 
     In a thirteenth aspect of the disclosure, there is provided a computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to the third aspect of the disclosure. 
     In a fourteenth aspect of the disclosure, there is provided a computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to the fourth aspect of the disclosure. 
     In a fifteenth aspect of the disclosure, there is provided a computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to the fifth aspect of the disclosure. 
     The embodiments of present disclosure may provide support for a specified service such as low latency communication service without deleting an old PDN connection and establishing a new PDN connection. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and benefits of various embodiments of the present disclosure will become more fully apparent, by way of example, from the following detailed description with reference to the accompanying drawings, in which like reference numerals or letters are used to designate like or equivalent elements. The drawings are illustrated for facilitating better understanding of the embodiments of the disclosure and not necessarily drawn to scale, in which: 
         FIG. 1  schematically shows a system according to an embodiment of the present disclosure; 
         FIG. 2  schematically shows a system according to another embodiment of the present disclosure; 
         FIG. 3  shows a flowchart of a method according to an embodiment of the present disclosure; 
         FIG. 4  shows a flowchart of a method according to another embodiment of the present disclosure; 
         FIG. 5  shows a flowchart of a method according to another embodiment of the present disclosure; 
         FIG. 6  shows a flowchart of a method according to another embodiment of the present disclosure; 
         FIG. 7  shows a flowchart of a method according to another embodiment of the present disclosure; 
         FIG. 8  shows a flowchart of a method according to another embodiment of the present disclosure; 
         FIGS. 9 a -9 e    illustrate simplified block diagrams of an apparatus in PGW-C, additional PGW-U, SGW-C, SGW-U and initial PGW-U respectively, according to an embodiment of the present disclosure; 
         FIG. 10  illustrates a simplified block diagram of an apparatus for a PGW-C according to an embodiment of the present disclosure; 
         FIG. 11  illustrates a simplified block diagram of an apparatus for an additional PGW-U according to an embodiment of the present disclosure; 
         FIG. 12  illustrates a simplified block diagram of an apparatus for a SGW-C according to an embodiment of the present disclosure; 
         FIG. 13  illustrates a simplified block diagram of an apparatus for a SGW-U according to an embodiment of the present disclosure; and 
         FIG. 14  illustrates a simplified block diagram of an apparatus for an initial PGW-U according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For the purpose of explanation, details are set forth in the following description in order to provide a thorough understanding of the embodiments disclosed. It is apparent, however, to those skilled in the art that the embodiments may be implemented without these specific details or with an equivalent arrangement. 
     The term “network function” refers to any suitable function which can be implemented in a network device of a wireless communication network via which a terminal device can access the network and receives services therefrom. In the wireless communication network, the network device may refer to Mobility Management Entity (MME), Serving GateWay (SGW), Packet Data Network GateWay (PGW), Policy and Charging Rules Function (PCRF), Home Subscriber Server (HSS) or any other suitable device in the wireless communication network. It is noted that the network function may comprise different network elements depending on the type of network. 
     The term “terminal device” refers to any end device that can access a wireless communication network and receive services therefrom. By way of example and not limitation, the terminal device refers to a mobile terminal, user equipment (UE), or other suitable devices. The UE may be, for example, a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, portable computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, wearable terminal devices, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE) and the like. In the following description, the terms “terminal device”, “terminal”, “user equipment” and “UE” may be used interchangeably. As one example, a terminal device may represent a UE configured for communication in accordance with one or more communication standards promulgated by the 3GPP (3rd Generation Partnership Project), such as 3GPP&#39;s GSM, UMTS, LTE standards. As used herein, a “user equipment” or “UE” may not necessarily have a “user” in the sense of a human user who owns and/or operates the relevant device. In some embodiments, a terminal device may be configured to transmit and/or receive information without direct human interaction. For instance, a terminal device may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the wireless communication network. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but that may not initially be associated with a specific human user. 
     As yet another example, in an Internet of Things (IOT) scenario, a terminal device may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another terminal device and/or network equipment. The terminal device may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as a machine-type communication (MTC) device. As one particular example, the terminal device may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances, for example refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a terminal device may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. 
     References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed terms. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be liming of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and/or “including”, when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. 
     In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs. 
     For illustrative purposes, several embodiments of the present disclosure will be described in the context of a wireless core network and a low latency communication (LLC) service. Those skilled in the art will appreciate, however, that the concept and principle of the several embodiments of the present disclosure may be more generally applicable to any other suitable networks and service. 
     There is also ongoing study in 3GPP, i.e., in 3GPP TR23.739, for “enhancement of EPC for low latency communication including device mobility”. A purpose of this study is how to select a new and local user plane with low latency which can meet LLC requirement when the service requiring low latency is detected and/or UE moves to a new location. Some solutions have been identified in TR 23.739. 
     A solution in TR 23.739 is to select a local user plane by establishing a new packet data network (PDN) connection for the LLC. The problems of this solution may comprise much extra signaling in the network for the PDN connection establishment and deletion, service not being able to be served with low latency before the PDN establishment procedure is completed and UE being impacted. 
     Another solution in TR 23.739 is to keep the existing control plane of a serving gateway (SGW-C) and control plane of PDN gateway (PGW-C) (as combined one) and an initial user plane of the PGW (PGW-U) and select a new user plane node with both a user plane of the SGW (SGW-U) and PGW-U function. The new user plane supports UL CL (UpLink Classifier) function so that the service data flows for the LLC (Low Latency Communication) application can break out locally to data network. The problems of this solution may comprise the assumptions of combining SGW-C with PGW-C and combining SGW-U with additional PGW-U are not always applicable and changing the SGW-U to be collocated with the additional PGW-U will cause extra signaling in network and add the delay of local network serving the LLC service. 
     To overcome or mitigate at least one of above mentioned problems or other problems, the embodiments of the present disclosure propose a solution to support addition of additional PGW-U. The addition of additional PGW-U may be triggered based on various conditions for example when a low latency communication service is detected and/or UE mobility is detected which requires to setup a new local user plane close to a local data network. With introduction of the additional PGW-U, there may be the uplink classification (UL CL) functionality in the network so that uplink packets for a specified service such as LLC are sent to the additional PGW-U and the other services are sent to initial PGW-U. There may be two options regarding where the UL CL is located: one is SGW-U supporting the UL CL functionality and the other one is the additional PGW-U supporting the UL CL functionality. 
       FIG. 1  schematically shows a system according to an embodiment of the present disclosure. As shown in  FIG. 1 , the system  100  may comprise a PGW control plane (PGW-C)  102 , a PGW additional user plane (PGW-U)  104 , a SGW control plane (SGW-C)  106 , a SGW user plane (SGW-U)  108 , an initial PGW-U  110 , UE  112 , a first data network  114  and a second data network  116 . A PDN connection may be used by UE  112  to connect to the first data network  114  through at least SGW-U  108  and an initial user plane of PGW (i.e., PGW-U  110 ), and an additional user plane of the PGW (i.e., PGW-U  104 ) may be used for connecting UE  112  with the second data network  116 . The system  100  may be CUPS (Control and User Plane Separation) architecture as defined in 3GPP TS23.214. With CUPS, Sxb interface is defined between PGW-C and PGW-U and Sxa interface is defined between SGW-C and SGW-U. CUPS provides the architecture enhancements for the separation of functionality in the Evolved Packet Core functionality such as SGW, PGW, TDF (Traffic Detection Function), etc. This enables flexible network deployment and operation, by distributed or centralized deployment and the independent scaling between control plane and user plane functions while not affecting the functionality of the existing nodes subject to this split. 
     In system  100 , SGW-U  108  implements an uplink classifier (UL CL) function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network  116  through PGW-U  104 . 
     During PDN connection setup or mobility, if SGW-C  106  knows, e.g., by local configuration or informed by other node, that a specified service such as low latency communication service is applicable for this PDN, SGW-C  106  may try to select SGW-U  108  which supports UL CL. 
     When a local PGW-U (referred to as additional PGW-U) needs to be selected, the PDN connection and the initial PGW-U  110  may be kept while PGW-C  102  may select an additional PGW-U  104  to serve the specified service data such as low latency communication service data in the PDN connection and this additional PGW-U  104  may be added to the current PDN connection. 
     The current UE IP address may be kept unchanged. If the additional PGW-U  104  and the initial PGW-U  110  are in a different IP domain and if the UE IP address is also supported by the additional PGW-U  104 , the UE IP address may be directly used by the additional PGW-U  104  for data matching and routing. Otherwise PGW-C  102  may allocate a new IP address as additional UE IP address and this information may be provided to the additional PGW-U  104 . 
     The additional PGW-U  104  does a network address translation (NAT) between an initial UE IP address and the additional UE IP address. 
     PGW-C  102  provides the additional PGW-U information, e.g., an IP address and the new S5/S8-U PGW F-TEID (Fully Qualified tunnel endpoint identifier), to SGW-C  106  together with instruction information, such as service data flow filter (SDF) and/or application identity (ID) information, indicating which IP flow should be delivered to the additional PGW-U  104 . In case of combined SGW-C  106  and PGW-C  102 , this step may be omitted. 
     SGW-C  106  forwards the additional PGW-U information together with the instruction information such as SDF Filter or Application ID information to SGW-U  108 . 
     SGW-U  108  classifies the uplink data for example using the SDF Filter or Application ID information and forwards the packet matching the SDF Filter or Application ID to the additional PGW-U  104  while for other data flows to the initial PGW-U  110 . 
       FIG. 2  schematically shows a system according to another embodiment of the present disclosure. As shown in  FIG. 2 , the system  200  may comprise PGW-C  202 , additional PGW-U  204 , SGW-C  206 , SGW-U  208 , initial PGW-U  210 , UE  212 , a first data network  214  and a second data network  216 . A PDN connection  218  may be used by UE  212  to connect to the first data network  214  through at least SGW-U  208  and initial PGW-U  210 . An additional PGW-U  204  may be used for connecting UE  212  with the second data network  216 . The system  200  may be CUPS (Control and User Plane Separation) architecture as defined in 3GPP TS23.214. For some parts which have been described in the above embodiments, detailed description thereof is omitted here for brevity. 
     In system  200 , the additional PGW-U  204  implements the UL CL function to enable the specified part of uplink data in the PDN connection to be forwarded to the second data network  116  through the additional PGW-U  204 . 
     When an additional PGW-U needs to be selected, the PDN connection and the initial PGW-U  210  may be kept while PGW-C  202  may select the additional PGW-U  204  which supports UL CL. PGW-C  202  may send, to the additional PGW-U  204 , address information of the initial PGW-U and instruction information indicating the specified part of uplink data in the PDN connection is forwarded to the second data network  216  and the other part of uplink data in the PDN connection is forwarded to the initial PGW-U  210 . 
     PGW-C  202  may send, to the PGW-U  210 , address information of additional PGW-U  204  and instruction information indicating that the PGW-U  210  switches communication from the SGW-U  208  to the additional PGW-U  204 . 
     The current UE IP address may be kept unchanged as described above. Otherwise PGW-C  202  may allocate a new IP address as additional UE IP address and this information is provided to the additional PGW-U  204 . The additional PGW-U  204  may perform NAT between the initial UE IP address and the additional UE IP address. 
     PGW-C  202  may provide the additional PGW-U information, e.g., an IP address and the new S5/S8-U PGW F-TEID (Fully Qualified tunnel endpoint identifier), to SGW-C  206  together with instruction information indicating that all the uplink data in the PDN connection is forwarded to the additional PGW-U  204 . 
     SGW-C  206  may send address information of PGW-U  204  and instruction information to SGW-U  208  which may send all the uplink data in the PDN connection to the additional PGW-U  204  based on the instruction information. 
     SGW-C  206  may initiate the PFCP (Packet Forwarding Control Plane (PFCP) protocol) session modification procedure towards the SGW-U  208  and in a PFCP Session Modification Request message, and the access side S5/8-U PGW F-TEID of the additional PGW-U  204  may be included. SGW-U  208  may switch a S5/8-U tunnel from the initial PGW-U  210  to the additional PGW-U  204 . 
     Then PGW-U  210  may perform data handling according to the instruction information. For downlink data both from the initial PGW-U  210  and the second data network  216 , PGW-U  210  may send it to the SGW-U  108 . For uplink data which is classified as the specified service such as LLC service, this data is directly sent to the second data network  216  for example over a SGi interface, and for other uplink data, it is sent to the initial PGW-U  210 . 
       FIG. 3  shows a flowchart of a method according to an embodiment of the present disclosure. The method  300  may be implemented at PGW-C in a wireless network such as PGW-Cs  106  and  206  as shown in  FIGS. 1 and 2 . 
     As shown in  FIG. 3 , the method  300  may start at block  302  where PGW-C may determine that an additional PGW-U for a PDN connection needs to be allocated. The PDN connection may be used by a UE to connect to a first data network through at least a SGW-U of the wireless network and an initial PGW-U. The additional PGW-U may be used for connecting with a second data network. The first and second data networks may be same or different data networks. UE may access a service through the first or second data network and the service quality such as service latency provided by the first and second data network may be different. For example, if UE accesses the service through the second data network, UE may achieve low latency and/or low packet loss and/or low cost for the service as compare to accessing the service through the first data network. 
     PGW-C may determine that an additional PGW-U for a PDN connection needs to be allocated based on various criterions. In an embodiment, PGW-C may determine that the additional PGW-U for the PDN connection needs to be allocated based on at least one of a detection of a low latency communication service in the PDN connection, the UE&#39;s location change with ongoing low latency communication service and a request from a network function such as AF (application function) or PCRF (Policy and Charging Rules Function). As an example, the operator may have prior knowledge of which applications (and which UEs) they want to provide with low latency. When the application detection is performed in the TDF, the PCRF may request the TDF to detect when a UE is using those applications. Upon the reporting of the detection of the application, the PCRF may request the PGW-C to use the low latency PGW-U for those applications. As another example, the allocation of the additional PGW-U for the PDN connection may be initiated by the PGW-C after the UE mobility event. As still another example, if AF is aware that edge compute resources are available in a Presence Reporting Area and that there is a PGW-U for breakout to the edge compute resources which can benefit from the UE. The AF may provide a trigger to the PCRF that the LLC is required for this service. Then this trigger may be provided to the PGW-C. As still another example, when the application detection is performed in the PCEF, the PCRF installs a PCC (Policy and Charging Control) rule including the SDF templates and an indication that the SDF requires a LLC PDN connection. Upon the detection of the SDF in the PCEF, the PGW-C may determine that an additional PGW-U for the PDN connection needs to be allocated. 
     At block  304 , PGW-C may select the additional PGW-U. PGW-C may select the additional PGW-U based on various criterions. In an embodiment, PGW-C may select the additional PGW-U which is close to the UE&#39;s location. For example, the PGW-C may use User Location Reporting/Presence Reporting Area to know the UE&#39;s current location, and then uses its Domain Name System (DNS) to determine the correct additional PGW-U. Then PGW-C may initiate a PFCP session establishment procedure towards the newly selected PGW-U to setup the PFCP session. 
     At block  306  (optional), if an initial UE IP address for the PDN connection is not supported and/or cannot be directly used by the additional PGW-U, then PGW-C may allocate an additional UE IP address used by the additional PGW-U. For example, if the additional PGW-U is in the same IP domain as the initial PGW-U which means the initial UE IP address cannot be directly used by the additional PGW-U to route the traffic over SGi interface, PGW-C may allocate the additional UE IP address which is used by the additional PGW-U over SGi interface. 
     At block  308  (optional), PGW-C may send the initial UE IP address and the additional UE IP address to the additional PGW-U to enable the additional PGW-U to perform NAT between the initial UE IP address and additional UE IP address when data is exchanged between the UE and the second data network through the additional PGW-U. For example, both the initial UE IP address and the additional UE IP address may be sent to the additional PGW-U for packet matching and network address translation as below:
         For uplink data: the additional PGW-U may use the initial UE IP address for packet matching and translate the initial UE IP address to the additional UE IP address when the specified part of uplink data is sent over for example the SGi interface;   For downlink data: the additional PGW-U may use the additional UE IP address for packet matching and translate the additional UE IP address to the initial UE IP address when the downlink data is sent over for example a S5/8 interface.       

     At block  310 , PGW-C may send address information of the additional PGW-U and instruction information to SGW-C. The address information may be any suitable address such as IP address, a tunnel endpoint identifier, etc. The instruction information may be used by the SGW-C to instruct SGW-U to forward the uplink data in the PDN connection based on the instruction information. The address information and the instruction information may be comprised in any suitable message. For example, PGW-C may send an update bearer request or modify bearer response (if mobility procedure is ongoing) to the SGW-C to add the address information and the instruction information. For example, the address information such as S5/8-U PGW F-TEID of the additional PGW-U and the instruction information such as the corresponding SDF Filter and/or Application ID information may be included in the update bearer request or modify bearer response. The SDF Filter and/or Application ID information may indicate that service data flows for a specified service such as LLC should be delivered to the additional PGW-U. SGW-C may store the instruction information together with address information such as the S5/8-U PGW F-TEID of the additional PGW-U. If there is a mobility procedure (e.g., handover) ongoing with SGW-C relocation, PGW-C may include the address information and the instruction information in a Modify Bearer Response sent to a new SGW-C. 
     In an embodiment, the SGW-U or the additional PGW-U may implement an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional PGW-U. The specified part of uplink data may comprise any suitable service data such as low latency communication service data, etc. 
     In an embodiment, the SGW-U implements the uplink classifier function and the instruction information may indicate that the specified part of uplink data in the PDN connection is forwarded to the second data network through the additional PGW-U and the other part of uplink data in the PDN connection is forwarded to the first data network through the initial PGW-U. For example, the SGW-U may already support uplink classifier function because when this SGW-U is selected, SGW-C may have already considered this based on an indication that this PDN connection is applicable for a specified service such as LLC. The address information of the additional PGW-U may comprise an IP address and a tunnel endpoint identifier of the additional PGW-U and the instruction information may comprise SDF filter and/or application ID information associated with the specified part of uplink data. 
       FIG. 4  shows a flowchart of a method according to another embodiment of the present disclosure. In this embodiment, the additional PGW-U implements the uplink classifier function and the instruction information may indicate that all the uplink data in the PDN connection is forwarded to the additional PGW-U. The method  400  may be implemented at a PGW-C such as PGW-Cs  106  and  206  as shown in  FIGS. 1 and 2 . For some parts which have been described in the above embodiments, detailed description thereof is omitted here for brevity. 
     As shown in  FIG. 4 , the method  400  may comprise determining that an additional PGW-U for a PDN connection needs to be allocated at block  402 ; selecting the additional user plane of the PGW at block  404 ; allocating an additional UE Internet protocol (IP) address used by the additional user plane of the PGW if an initial UE IP address for the PDN connection is not supported and/or cannot be directly used by the additional user plane of the PGW at block  406 ; sending the initial UE IP address and the additional UE IP address to the additional user plane of the PGW to enable the additional user plane of the PGW to perform NAT between the initial UE IP address and additional UE IP address when data is exchanged between the UE and the second data network through the additional user plane of the PGW at block  408 . Blocks  402 ,  404 ,  406  and  408  are similar to blocks  302 ,  304 ,  306  and  308  of  FIG. 3 , and detailed description thereof is omitted here for brevity. 
     At block  410 , PGW-C may send address information of the additional PGW-U and instruction information to the SGW-C. The address information may be any suitable address such as IP address, a tunnel endpoint identifier, etc. For example, PGW-C may send an update bearer request or modify bearer response (if mobility procedure is ongoing) to SGW-C. The address information such as access side S5/8-U PGW F-TEID of the additional PGW-U and the instruction information may be included in the update bearer request or modify bearer response. The access side S5/8-U PGW F-TEID of the additional PGW-U may be to replace the S5/8-U PGW F-TEID of the initial PGW-U. After receiving the address information and the instruction information, SGW-C may initiate a PFCP session modification procedure towards the SGW-U and in the PFCP Session Modification Request message which may comprise address information such as the access side S5/8-U PGW F-TEID of the additional PGW-U and the instruction information. SGW-U then switches the S5/8-U tunnel from initial PGW-U to the additional PGW-U after receiving the address information and the instruction information. 
     At block  412 , PGW-C may send, to the additional PGW-U, address information of the initial PGW-U and instruction information indicating the specified part of uplink data in the PDN connection is forwarded to the second data network and the other part of uplink data in the PDN connection is forwarded to the initial PGW-U. In an embodiment, the address information of the initial PGW-U may comprise an IP address and a tunnel endpoint identifier of the initial PGW-U, and the instruction information sent to the additional PGW-U may comprise service data flow filter and/or application identity information associated with the specified part of uplink data. For example, PGW-C may include SDF filter and/or application ID information in one or more PDRs (Packet Detection Rules) which may be used to match the specified service such as LLC service in the uplink data and PGW-C may also include PDRs to match other service data in the uplink data. PGW-C may include the S5/8-U F-TEID of the initial PGW-U in one or more FARs (Forward Action Rules) which may be used for routing other service in the uplink data such as non-LLC service. 
     At block  414 , PGW-C may send, to the initial PGW-U, address information of the additional PGW-U and instruction information indicating that the initial PGW-U switches communication from the SGW-U to the additional PGW-U. In an embodiment, the address information of the additional PGW-U comprises an IP address and a tunnel endpoint identifier of the additional PGW-U. For example, PGW-C may initiate the PFCP session modification procedure towards the initial PGW-U. In PFCP Session Modification Request message, the IP address and the core side S5/8-U F-TEID information of the additional PGW-U may be included so that the initial PGW-U switches the S5/8-U tunnel from SGW-U to the additional PGW-U. 
     In an embodiment, PGW-C may initiate a session deletion procedure towards an old additional user plane of the PGW if there is an old additional user plane of the PGW at block  312  (optional) of  FIG. 3  and block  416  (optional) of  FIG. 4 . For example, if there is already an old additional PGW-U allocated for the specified part of uplink data in the PDN connection and the PGW-C has known that the specified part of uplink data has been forwarded to the second data network through the new additional PGW-U, then PGW-C may initiate the PFCP session deletion procedure towards the old additional PGW-U. 
       FIG. 5  shows a flowchart of a method according to another embodiment of the present disclosure. The method  500  may be implemented at an additional PGW-U in a wireless network. A PDN connection may be used by a UE to connect to a first data network through at least a SGW-U of the wireless network and an initial PGW-U. The additional PGW-U may be used for connecting with a second data network. For some parts which have been described in the above embodiments, detailed description thereof is omitted here for brevity. 
     As shown in  FIG. 5 , the method  500  may start at block  502  where the additional PGW-U may receive, from a PGW-C, address information of the initial PGW-U and instruction information indicating the specified part of uplink data in the PDN connection is forwarded to the second data network and the other part of uplink data in the PDN connection is forwarded to the initial PGW-U. For example, PGW-C may send the address information and the instruction information at block  412  of  FIG. 4 , and then the additional PGW-U may receive this information. 
     In an embodiment, the address information of the initial PGW-U may comprise an IP address and a tunnel endpoint identifier of the initial PGW-U. The instruction information may comprise service data flow filter and/or application identity information associated with the specified part of uplink data. 
     In an embodiment, the specified part of uplink data may comprise low latency communication service data. 
     At block  504  (optional), the additional PGW-U may receive an initial UE IP address for the PDN connection and an additional UE IP address allocated by the PGW-C and perform NAT between the initial UE IP address and the additional UE IP address when data is exchanged between the UE and the second data network through the additional user plane of the PGW at block  506  (optional). For example, PGW-C may send the initial UE IP address and the additional UE IP address to the additional PGW-U at block  308  of  FIG. 3  or block  408  of  FIG. 4  as described above. 
     At block  508 , the additional PGW-U may receive the uplink data from SGW-U. For example, PGW-C may send address information of the additional PGW-U and instruction information to SGW-C, wherein the instruction information may indicate that all the uplink data in the PDN connection is forwarded to the additional PGW-U. Then SGW-C may instruct SGW-U to forward all the uplink data in the PDN connection to the additional PGW-U. 
     At block  510 , the additional PGW-U may forward the uplink data based on the instruction information. For example, if the specified part of uplink data is LLC service, then for uplink data which is classified as the LLC service, the uplink data may be directly forwarded to the second data network for example over SGi interface and the other uplink data may be forwarded to the initial PGW-U. In addition, for downlink data both from the initial PGW-U and the second network, it may be sent to the SGW-U. 
       FIG. 6  shows a flowchart of a method according to another embodiment of the present disclosure. The method  600  may be implemented at a SGW-C in a wireless network. A PDN connection may be used by a UE to connect to a first data network through at least a SGW-U of the wireless network and an initial PGW-U of the wireless network. The additional PGW-U may be used for connecting with a second data network. The SGW-U or the additional PGW-U may implement an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional PGW-U. For some parts which have been described in the above embodiments, detailed description thereof is omitted here for brevity. 
     As shown in  FIG. 6 , the method  600  may start at block  602  where SGW-C may receive, from a PGW-C, address information of the additional PGW-U and instruction information from PGW-C. For example, PGW-C may send the address information and the instruction information at block  310  of  FIG. 3  or block  410  of  FIG. 4 , and then the SGW-C may receive this information. 
     At block  604 , SGW-C may send the address information of the additional PGW-U and the instruction information to the SGW-U. In an embodiment, the information sent to the SGW-U may be included in a packet forwarding control protocol session modification request. 
     In an embodiment, the method  600  may further comprise selecting the SGW-U supporting uplink classifier function at block  601  (optional). For example, SGW-C may select the SGW-U supporting uplink classifier function when the PDN connection is established based on an indication that the PDN connection is applicable for a specified service such as LLC. 
     In an embodiment, the SGW-U may implement the uplink classifier function and the instruction information may indicate that the specified part of uplink data in the PDN connection is forwarded to the second data network through the additional user plane of the PGW and the other part of uplink data in the PDN connection is forwarded to the initial PGW-U through the PDN connection. In an embodiment, the address information may comprise an IP address and a tunnel endpoint identifier of the additional PGW-U and the instruction information may comprise service data flow filter and/or application identity information associated with the specified part of uplink data. 
     In an embodiment, the additional PGW-U may implement the uplink classifier function and the instruction information may indicate that all the uplink data in the PDN connection is forwarded to the additional user plane of the PGW. In an embodiment, the address information of the additional user plane of the PGW may comprise an IP address and a tunnel endpoint identifier of the additional PGW-U. 
       FIG. 7  shows a flowchart of a method according to an embodiment of the present disclosure. The method  700  may be implemented at a SGW-U in a wireless network. A PDN connection may be used by a UE to connect to a first data network through at least a SGW-U and an initial PGW-U of the wireless network. The additional PGW-U may be used for connecting with a second data network. The SGW-U or the additional PGW-U may implement an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional PGW-U. The specified part of uplink data may comprise low latency communication service data. For some parts which have been described in the above embodiments, detailed description thereof is omitted here for brevity. 
     As shown in  FIG. 7 , the method  700  may start at block  702  where SGW-U may receive, from a SGW-C, address information of the additional PGW-U and instruction information. For example, SGW-C may send to SGW-U the address information of the additional PGW-U and instruction information at block  604  of  FIG. 6 . In an embodiment, the information received from the SGW-C may be included in a packet forwarding control protocol session modification request. 
     At block  704 , SGW-U may process the uplink data in the PDN connection according to the instruction information. 
     In an embodiment, the SGW-U implements the uplink classifier function and the instruction information may indicate that the specified part of uplink data in the PDN connection is forwarded to the second data network through the additional PGW-U and the other part of uplink data in the PDN connection is forwarded to the first data network through the initial PGW-U. In an embodiment, the address information may comprise an IP address and a tunnel endpoint identifier of the additional PGW-U and the instruction information comprises service data flow filter and/or application identity information associated with the specified part of uplink data. For example, if the specified part of uplink data is LLC service, then for uplink data which is classified as the LLC service, the uplink data may be directly forwarded to the additional PGW-U which may send it to the second data network for example over SGi interface and the other uplink data may be forwarded to the initial PGW-U. In addition, for downlink data both from the initial PGW-U and the additional PGW-U, it may be sent to the UE. 
     In an embodiment, the additional PGW-U implements the uplink classifier function and the instruction information may indicate that all the uplink data in the PDN connection is forwarded to the additional user plane of the PGW. In an embodiment, the address information of the additional PGW-U comprises an IP address and a tunnel endpoint identifier of the additional user plane of the PGW. In this embodiment, SGW-C may forward all the uplink data to the additional PGW-U. 
       FIG. 8  shows a flowchart of a method according to an embodiment of the present disclosure. The method  800  may be implemented at an initial PGW-U in a wireless network. A PDN connection may be used by a UE to connect to a first data network through at least a SGW-U of the wireless network and the initial PGW-U. An additional PGW-U may be used for connecting with a second data network. The SGW-U or the additional PGW-U may implement an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional PGW-U. The specified part of uplink data may comprise low latency communication service data. For some parts which have been described in the above embodiments, detailed description thereof is omitted here for brevity. 
     As shown in  FIG. 8 , the method  800  may start at block  802  where the initial PGW-U may receive from a PGW-C, address information of the additional PGW-U and instruction information indicating that the initial PGW-U switches communication from the SGW-U to the additional PGW-U. 
     At block  804 , the initial PGW-U may switch communication from the SGW-U to the additional PGW-U. 
       FIG. 9 a    illustrates a simplified block diagram of an apparatus  910  that may be embodied in/as PGW-C in a wireless network according to an embodiment of the present disclosure.  FIG. 9 b    illustrates an apparatus  920  that may be embodied in/as an additional PGW-U in a wireless network according to an embodiment of the present disclosure.  FIG. 9 c    shows an apparatus  930  that may be embodied in/as a SGW-C in a wireless network according to an embodiment of the present disclosure.  FIG. 9 d    shows an apparatus  940  that may be embodied in/as a SGW-U in a wireless network according to an embodiment of the present disclosure.  FIG. 9 e    shows an apparatus  950  that may be embodied in/as an initial PGW-U in a wireless network according to an embodiment of the present disclosure. 
     The apparatus  910  may comprise at least one processor  911 , such as a data processor (DP) and at least one memory (MEM)  912  coupled to the processor  911 . The apparatus  910  may further comprise a transmitter TX and receiver RX  913  coupled to the processor  911 . The MEM  912  stores a program (PROG)  914 . The PROG  914  may include instructions that, when executed on the associated processor  911 , enable the apparatus  910  to operate in accordance with the embodiments of the present disclosure, for example to perform the methods  300 ,  400 . A combination of the at least one processor  911  and the at least one MEM  912  may form processing means  915  adapted to implement various embodiments of the present disclosure. 
     The apparatus  920  comprises at least one processor  921 , such as a DP, and at least one MEM  922  coupled to the processor  921 . The apparatus  920  may further comprise a transmitter TX and receiver RX  923  coupled to the processor  921 . The MEM  922  stores a PROG  924 . The PROG  924  may include instructions that, when executed on the associated processor  921 , enable the apparatus  920  to operate in accordance with the embodiments of the present disclosure, for example to perform the method  500 . A combination of the at least one processor  921  and the at least one MEM  922  may form processing means  925  adapted to implement various embodiments of the present disclosure. 
     The apparatus  930  comprises at least one processor  931 , such as a DP, and at least one MEM  932  coupled to the processor  931 . The apparatus  930  may further comprise a transmitter TX and receiver RX  933  coupled to the processor  931 . The MEM  932  stores a PROG  934 . The PROG  934  may include instructions that, when executed on the associated processor  921 , enable the apparatus  930  to operate in accordance with the embodiments of the present disclosure, for example to perform the method  600 . A combination of the at least one processor  931  and the at least one MEM  932  may form processing means  935  adapted to implement various embodiments of the present disclosure. 
     The apparatus  940  may comprise at least one processor  941 , such as a data processor (DP) and at least one memory (MEM)  942  coupled to the processor  941 . The apparatus  940  may further comprise a transmitter TX and receiver RX  943  coupled to the processor  941 . The MEM  942  stores a program (PROG)  944 . The PROG  944  may include instructions that, when executed on the associated processor  941 , enable the apparatus  940  to operate in accordance with the embodiments of the present disclosure, for example to perform the method  700 . A combination of the at least one processor  941  and the at least one MEM  942  may form processing means  945  adapted to implement various embodiments of the present disclosure. 
     The apparatus  950  may comprise at least one processor  951 , such as a data processor (DP) and at least one memory (MEM)  952  coupled to the processor  951 . The apparatus  950  may further comprise a transmitter TX and receiver RX  953  coupled to the processor  951 . The MEM  952  stores a program (PROG)  954 . The PROG  954  may include instructions that, when executed on the associated processor  951 , enable the apparatus  950  to operate in accordance with the embodiments of the present disclosure, for example to perform the method  800 . A combination of the at least one processor  951  and the at least one MEM  952  may form processing means  955  adapted to implement various embodiments of the present disclosure. 
     Various embodiments of the present disclosure may be implemented by computer program executable by one or more of the processors  911 ,  921   931 ,  941  and  951 , software, firmware, hardware or in a combination thereof. 
     The MEMs  912 ,  922 ,  932 ,  942  and  952  may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. 
     The processors  911 ,  921   931 ,  941  and  951  may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors DSPs and processors based on multicore processor architecture, as non-limiting examples. 
     Reference is now made to  FIG. 10 , which illustrates a schematic block diagram of an apparatus  1000  for PGW-C in a wireless network. The apparatus  1000  is operable to carry out the exemplary methods  300 ,  400  described with reference to  FIGS. 3-4  and possibly any other processes or methods. 
     As shown in  FIG. 10 , the apparatus  1000  may comprise: a determining unit  1002  configured to determine that an additional user plane of the PGW for a PDN connection needs to be allocated, wherein the PDN connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and an initial user plane of the PGW, and the additional user plane of the PGW is used for connecting with a second data network; a selecting unit  1004  configured to select the additional user plane of the PGW; a sending unit  1006  configured to send address information of the additional user plane of the PGW and instruction information to a control plane of the SGW, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In an embodiment, the determining unit  1002  is configured to determine that an additional user plane of the PGW for a PDN connection needs to be allocated based on at least one of a detection of a low latency communication service in the PDN connection, the UE&#39;s location change with ongoing low latency communication service and a request from a network function. 
     In an embodiment, the selecting unit  1004  is configured to select the additional user plane of the PGW comprises selecting the additional user plane of the PGW which is close to the UE&#39;s location. 
     In an embodiment, the apparatus  1000  may further comprise: an allocating unit  1008  (optional) configured to allocate an additional UE Internet protocol (IP) address used by the additional user plane of the PGW if an initial UE IP address for the PDN connection is not supported and/or cannot be directly used by the additional user plane of the PGW; and the sending unit  1006  is configured to send the initial UE IP address and the additional UE IP address to the additional user plane of the PGW to enable the additional user plane of the PGW to perform a network address translation (NAT) between the initial UE IP address and additional UE IP address when data is exchanged between the UE and the second data network through the additional user plane of the PGW. 
     In an embodiment, the user plane of the SGW implements the uplink classifier function, the instruction information indicates that the specified part of uplink data in the PDN connection is forwarded to the second data network through the additional user plane of the PGW and the other part of uplink data in the PDN connection is forwarded to the first data network through the initial user plane of the PGW. 
     In an embodiment, the address information of the additional user plane of the PGW comprises an IP address and a tunnel endpoint identifier of the additional user plane of the PGW and the instruction information comprises service data flow filter and/or application identity information associated with the specified part of uplink data. 
     In an embodiment, the additional user plane of the PGW implements the uplink classifier function and the instruction information indicates that all the uplink data in the PDN connection is forwarded to the additional user plane of the PGW, and the sending unit  1006  is configured to send, to the additional user plane of the PGW, address information of the initial user plane of the PGW and instruction information indicating the specified part of uplink data in the PDN connection is forwarded to the second data network and the other part of uplink data in the PDN connection is forwarded to the initial user plane of the PGW; and send to the initial user plane of the PGW, address information of the additional user plane of the PGW and instruction information indicating that the initial user plane of the PGW switches communication from the user plane of the SGW to the additional user plane of the PGW. 
     In an embodiment, the address information of the additional user plane of the PGW comprises an IP address and a tunnel endpoint identifier of the additional user plane of the PGW, the address information of the initial user plane of the PGW comprises an IP address and a tunnel endpoint identifier of the initial user plane of the PGW, and the instruction information sent to the additional user plane of the PGW comprises service data flow filter and/or application identity information associated with the specified part of uplink data. 
     In an embodiment, the apparatus  1000  may further comprise a deleting unit  1010  (optional) configured to initiate a session deletion procedure towards an old additional user plane of the PGW if there is an old additional user plane of the PGW. 
     In an embodiment, the information sent to the control plane of the SGW is included in an update bearer request or a modify bearer response. 
     In an embodiment, the specified part of uplink data comprises low latency communication service data. 
     Reference is now made to  FIG. 11 , which illustrates a schematic block diagram of an apparatus  1000  for PGW-C in a wireless network. A PDN connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and an initial user plane of the PGW, the additional user plane of the PGW is used for connecting with a second data network. The apparatus  1100  is operable to carry out the exemplary method  500  described with reference to  FIG. 5  and possibly any other processes or methods. 
     As shown in  FIG. 11 , the apparatus  1100  may comprise: an receiving unit  1102  configured to receive from a control plane of a PGW, address information of the initial user plane of the PGW and instruction information indicating the specified part of uplink data in the PDN connection is forwarded to the second data network and the other part of uplink data in the PDN connection is forwarded to the initial user plane of the PGW; the receiving unit  1102  is further configured to receive the uplink data from the user plane of the SGW; and an forwarding unit  1104  configured to forward the uplink data based on the instruction information. 
     In an embodiment, the apparatus  1100  may comprise: the receiving unit  1102  further configured to receive an initial UE IP address for the PDN connection and an additional UE IP address allocated by the control plane of the PGW; and a NAT unit  1106  (optional) further configured to perform a network address translation (NAT) between the initial UE IP address and additional UE IP address when data is exchanged between the UE and the second data network through the additional user plane of the PGW. 
     In an embodiment, the address information of the initial user plane of the PGW comprises an IP address and a tunnel endpoint identifier of the initial user plane of the PGW, and the instruction information comprises service data flow filter and/or application identity information associated with the specified part of uplink data. 
     In an embodiment, the specified part of uplink data comprises low latency communication service data. 
     Reference is now made to  FIG. 12 , which illustrates a schematic block diagram of an apparatus  1200  for SGW-C in a wireless network. A packet data network (PDN) connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of the SGW and an initial user plane of a PDN gateway (PGW) of the wireless network, and the additional user plane of the PGW is used for connecting with a second data network. The apparatus  1200  is operable to carry out the exemplary method  600  described with reference to  FIG. 6  and possibly any other processes or methods. 
     As shown in  FIG. 12 , the apparatus  1200  may comprise: a receiving unit  1202  configured to receive address information of the additional user plane of the PGW and instruction information from the control plane of the PGW; and a sending unit  1204  configured to send the address information of the additional user plane of the PGW and instruction information to the user plane of the SGW, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In an embodiment, the apparatus  1200  may further comprise a selecting unit  1206  (optional) configured to select the user plane of the SGW supporting uplink classifier function, wherein the user plane of the SGW implements the uplink classifier function and the instruction information indicates that the specified part of uplink data in the PDN connection is forwarded to the second data network through the additional user plane of the PGW and the other part of uplink data in the PDN connection is forwarded to the initial user plane of the PGW through the PDN connection. 
     In an embodiment, the address information comprises an IP address and a tunnel endpoint identifier of the additional user plane of the PGW and the instruction information comprises service data flow filter and/or application identity information associated with the specified part of uplink data. 
     In an embodiment, the additional user plane of the PGW implements the uplink classifier function and the instruction information indicates that all the uplink data in the PDN connection is forwarded to the additional user plane of the PGW. 
     In an embodiment, the address information of the additional user plane of the PGW comprises an IP address and a tunnel endpoint identifier of the additional user plane of the PGW. 
     In an embodiment, the information sent to the user plane of the SGW is included in a packet forwarding control protocol session modification request. 
     In an embodiment, the specified part of uplink data comprises low latency communication service data. 
     Reference is now made to  FIG. 13 , which illustrates a schematic block diagram of an apparatus  1300  for SGW-U in a wireless network. A packet data network (PDN) connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of the SGW and an initial user plane of a PDN gateway (PGW) of a wireless network, the additional user plane of the PGW is used for connecting with a second data network. The apparatus  1300  is operable to carry out the exemplary method  700  described with reference to 
       FIG. 7  and possibly any other processes or methods. 
     As shown in  FIG. 13 , the apparatus  1300  may comprise: a receiving unit  1302  configured to receive, from a control plane of the SGW, address information of the additional user plane of the PGW and instruction information; and a processing unit  1304  configured to process the uplink data in the PDN connection according to the instruction information, wherein the user plane of the SGW or the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. 
     In an embodiment, the user plane of the SGW implements the uplink classifier function and the instruction information indicates that the specified part of uplink data in the PDN connection is forwarded to the second data network through the additional user plane of the PGW and the other part of uplink data in the PDN connection is forwarded to the first data network through the initial user plane of the PGW. 
     In an embodiment, the address information comprises an IP address and a tunnel endpoint identifier of the additional user plane of the PGW and the instruction information comprises service data flow filter and/or application identity information associated with the specified part of uplink data. 
     In an embodiment, the additional user plane of the PGW implements the uplink classifier function and the instruction information indicates that all the uplink data in the PDN connection is forwarded to the additional user plane of the PGW. 
     In an embodiment, the address information of the additional user plane of the PGW comprises an IP address and a tunnel endpoint identifier of the additional user plane of the PGW. 
     In an embodiment, the information received from the control plane of the SGW is included in a packet forwarding control protocol session modification request. 
     In an embodiment, the specified part of uplink data comprises low latency communication service data. 
     Reference is now made to  FIG. 14 , which illustrates a schematic block diagram of an apparatus  1400  for an initial PGW-U in a wireless network. A PDN connection is used by a user equipment (UE) to connect to a first data network through at least a user plane of a serving gateway (SGW) of the wireless network and the initial user plane of the PGW, an additional user plane of the PGW is used for connecting with a second data network, and the additional user plane of the PGW implements an uplink classifier function to enable a specified part of uplink data in the PDN connection to be forwarded to the second data network through the additional user plane of the PGW. The apparatus  1400  is operable to carry out the exemplary method  800  described with reference to  FIG. 8  and possibly any other processes or methods. 
     As shown in  FIG. 14 , the apparatus  1400  may comprise: an receiving unit  1402  configured to receive from a control plane of the PGW, address information of the additional user plane of the PGW and instruction information indicating that the initial user plane of the PGW switches communication from the user plane of the SGW to the additional user plane of the PGW; and a switching unit  1404  configured to switch communication from the user plane of the SGW to the additional user plane of the PGW. 
     In an embodiment, the address information of the additional user plane of the PGW comprises an IP address and a tunnel endpoint identifier of the additional user plane of the PGW. 
     It would be appreciated that, some units or modules in the apparatus  1000 ,  1100 ,  1200 ,  1300  or  1400  can be combined in some implementations. For example, in one embodiment, it is possible to use a single transceiving unit to send and receive the information. 
     According to an aspect of the disclosure it is provided a computer program product being tangibly stored on a computer readable storage medium and including instructions which, when executed on at least one processor, cause the at least one processor to carry out the method related to PGW-C as described above, such as the methods  300  and  400  and a part of methods  300  and  400 . 
     According to an aspect of the disclosure it is provided a computer program product being tangibly stored on a computer readable storage medium and including instructions which, when executed on at least one processor, cause the at least one processor to carry out the method related to the additional PGW-U as described above, such as the method  500  and a part of method  500 . 
     According to an aspect of the disclosure it is provided a computer program product being tangibly stored on a computer readable storage medium and including instructions which, when executed on at least one processor, cause the at least one processor to carry out the method related to SGW-C as described above, such as the method  600  and a part of method  600 . 
     According to an aspect of the disclosure it is provided a computer program product being tangibly stored on a computer readable storage medium and including instructions which, when executed on at least one processor, cause the at least one processor to carry out the method related to SGW-U as described above, such as the method  700  and a part of method  700 . 
     According to an aspect of the disclosure it is provided a computer program product being tangibly stored on a computer readable storage medium and including instructions which, when executed on at least one processor, cause the at least one processor to carry out the method related to the initial PGW-U as described above, such as the method  800  and a part of method  800 . 
     Although some embodiments are described in the context of exemplary systems shown in  FIGS. 1-2 , it should not be construed as limiting the spirit and scope of the present disclosure. The principle and concept of the present disclosure may be more generally applicable to other system/network architectures. 
     The embodiments of present disclosure may provide support for a specified service such as low latency communication service without deleting the old PDN connection and establishing a new PDN connection. 
     In addition, the present disclosure may also provide a carrier containing the computer program as mentioned above, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium. The computer readable storage medium can be, for example, an optical compact disk or an electronic memory device like a RAM (random access memory), a ROM (read only memory), Flash memory, magnetic tape, CD-ROM, DVD, Blue-ray disc and the like. 
     The techniques described herein may be implemented by various means so that an apparatus implementing one or more functions of a corresponding apparatus described with an embodiment comprises not only prior art means, but also means for implementing the one or more functions of the corresponding apparatus described with the embodiment and it may comprise separate means for each separate function, or means that may be configured to perform two or more functions. For example, these techniques may be implemented in hardware (one or more apparatuses), firmware (one or more apparatuses), software (one or more modules), or combinations thereof. For a firmware or software, implementation may be made through modules (e.g., procedures, functions, and so on) that perform the functions described herein. 
     Exemplary embodiments herein have been described above with reference to block diagrams and flowchart illustrations of methods and apparatuses. It will be understood that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, respectively, can be implemented by various means including computer program instructions. These computer program instructions may be loaded onto a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions which execute on the computer or other programmable data processing apparatus create means for implementing the functions specified in the flowchart block or blocks. 
     Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the subject matter described herein, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination. 
     While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any implementation or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular implementations. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. 
     It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The above described embodiments are given for describing rather than limiting the disclosure, and it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the disclosure as those skilled in the art readily understand. Such modifications and variations are considered to be within the scope of the disclosure and the appended claims. The protection scope of the disclosure is defined by the accompanying claims.