WO2019137264A1

WO2019137264A1 - Packet data network gateway, user equipment and serving gateway as well as method implemented thereon

Info

Publication number: WO2019137264A1
Application number: PCT/CN2018/125581
Authority: WO
Inventors: Min Zhu; Juying GAN; Jinyin Zhu
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2018-01-12
Filing date: 2018-12-29
Publication date: 2019-07-18

Abstract

A packet data network (PDN) gateway (PGW), a user equipment (UE) and a serving gateway (SGW) are disclosed for a wireless communication system. According to an embodiment, the PGW obtains information related to or having influence on a predetermined service that can be suspended in sleeping state of a UE. The PGW performs the predetermined service for the UE based on the obtained information. The obtained information may comprise power saving information that indicates whether a power saving functionality is enabled for the UE and possible maximum sleeping time. When the power saving functionality is enabled for the UE and the possible maximum sleeping time is long, a request may be sent for subscribing a reachability monitoring event for the UE. The predetermined service may be initiated in response to receipt of a reachability report indicating that the UE is in a reachable state.

Description

PACKET DATA NETWORK GATEWAY, USER EQUIPMENT AND SERVING GATEWAY AS WELL AS METHOD IMPLEMENTED THEREON

Technical Field

Embodiments of the disclosure generally relate to wireless communication, and, more particularly, to a packet data network (PDN) gateway (PGW) , a user equipment (UE) and a serving gateway (SGW) as well as a method implemented thereon.

Background

This section introduces aspects that may facilitate better understanding of the present 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.

For cognitive Internet of things (CIoT) devices (or UEs) , 3rd generation partnership project (3GPP) has defined power saving mode (PSM) which can dramatically reduce their power consumption. When PSM is enabled, the UE is not reachable for a terminating service if the UE is in power saving state, i.e. sleeping state. The maximum sleeping time can be up to more than one year. The UE can wake up any time for an originating service. Each time the UE wakes up, there is much more power consumption.

Summary

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

One of the objects of the disclosure is to reduce the power consumption of a UE.

According to one aspect of the disclosure, there is provided a method implemented at a PGW. The method comprises obtaining information related to or having influence on a predetermined service that can be suspended in sleeping state of a UE. The method further comprises performing the predetermined service for the UE based on the obtained information.

In an embodiment of the disclosure, obtaining the information comprises receiving power saving information that indicates whether a power saving functionality is enabled for the UE. Performing the predetermined service comprises, when the power saving functionality is enabled for the UE, sending a request for subscribing a reachability monitoring event for the UE. Performing the predetermined service further comprises initiating the predetermined service in response to receipt of a reachability report indicating that the UE is in a reachable state.

In an embodiment of the disclosure, obtaining the information comprises receiving power saving information that indicates whether a power saving functionality is enabled for the UE and possible maximum sleeping time in a case where the power saving functionality is enabled for the UE. Performing the predetermined service comprises, when the power saving functionality is enabled for the UE and the possible maximum sleeping time is longer than or equal to a first predetermined threshold, sending a request for subscribing a reachability monitoring event for the UE. Performing the predetermined service further comprises initiating the predetermined service in response to receipt of a reachability report indicating that the UE is in a reachable state.

In an embodiment of the disclosure, performing the predetermined service comprises, when the power saving functionality is enabled for the UE and the possible maximum sleeping time is shorter than the first predetermined threshold, initiating the predetermined service at a predetermined timing.

In an embodiment of the disclosure, obtaining the information comprises receiving power saving information that indicates whether a power saving functionality is enabled for the UE and possible maximum sleeping time in a case where the power saving functionality is enabled for the UE. Performing the predetermined service comprises, when the power saving functionality is enabled for the UE, determining a target timing according to the possible maximum sleeping time. Performing the predetermined service further comprises initiating the predetermined service at the target timing.

In an embodiment of the disclosure, performing the predetermined service comprises, when the power saving functionality is not enabled for the UE, initiating the predetermined service at a predetermined timing.

In an embodiment of the disclosure, the power saving information is received in a Create Session Request message and/or a Modify Bearer Request message. The request for subscribing a reachability monitoring event is an Update Bearer Request message. The reachability report is a Modify Bearer Request message.

In an embodiment of the disclosure, the predetermined service is an IPv6 Stateless Address autoconfiguration service for the UE.

In an embodiment of the disclosure, the predetermined service is an IPv6 Stateless Address autoconfiguration service for the UE. Obtaining the information comprises receiving an indication that the UE supports extended router lifetime field in a Routing Advertisement message. The extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE. Performing the predetermined service comprises sending a Routing Advertisement message including the extended router lifetime field having the target value.

In an embodiment of the disclosure, the target value is expressed by a binary value greater than the possible maximum sleeping time of the UE. Alternatively, the target value is expressed by a specific value which is predetermined to represent infinity.

In an embodiment of the disclosure, the indication is received in a Create Session Request message.

According to another aspect of the disclosure, there is provided a method implemented at a UE with a power saving functionality. The method comprises detecting a trigger event which is to trigger the UE to wake up from sleeping state. The method further comprises determining whether the trigger event is to trigger a predetermined service that can be suspended in sleeping state. The method further comprises, when the trigger event is to trigger the predetermined service, keeping the UE in sleeping state. The method further comprises, when the trigger event is not to trigger the predetermined service, waking the UE up.

In an embodiment of the disclosure, the method further comprises, when a trigger event has been previously determined to trigger the predetermined service, initiating the predetermined service after the UE wakes up.

According to another aspect of the disclosure, there is provided a UE with a power saving functionality. The method comprises sending an indication that the UE supports extended router lifetime field in a Routing Advertisement message. The extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE. The method further comprises receiving a Routing Advertisement message including the extended router lifetime field having the target value, such that the target value is used as the UE’s router lifetime.

In an embodiment of the disclosure, the indication is sent in a PDN Connectivity Request message.

According to another aspect of the disclosure, there is provided a method implemented at a SGW. The method comprises determining whether to perform message inspection for a predetermined service that can be suspended in sleeping state of a UE. The method further comprises, when determining to perform message inspection, determining whether there is a redundant message buffered for the UE for the predetermined service. The method further comprises, when determining that there is the redundant message, dropping the redundant message.

In an embodiment of the disclosure, it is determined to perform message inspection when one of following events occurs: it is determined that the UE is in sleeping state; and it is determined that buffering duration indicated in a received Downlink Data Notification Acknowledgement (DDNA) message is longer than a second predetermined threshold.

In an embodiment of the disclosure, the method further comprises forwarding a request for subscribing a reachability monitoring event for the UE, from a PGW to a MME. The method further comprises forwarding a reachability report indicating that the UE is in a reachable state, from the MME to the PGW.

According to another aspect of the disclosure, there is provided a PGW. The PGW comprises a processor and a memory. The memory contains instructions executable by the processor, whereby the PGW is operative to obtain information related to or having influence on a predetermined service that can be suspended in sleeping state of a UE. The PGW is further operative to perform the predetermined service for the UE based on the obtained information.

In an embodiment of the disclosure, the PGW is operative to perform the method according to the above aspect.

According to another aspect of the disclosure, there is provided a UE with a power saving functionality. The UE comprises a processor and a memory. The memory contains instructions executable by the processor, whereby the UE is operative to detect a trigger event which is to trigger the UE to wake up from sleeping state. The UE is further operative to determine whether the trigger event is to trigger a predetermined service that can be suspended in sleeping state. The UE is further operative to, when the trigger event is to trigger the predetermined service, keep the UE in sleeping state. The UE is further operative to, when the trigger event is not to trigger the predetermined service, wake the UE up.

In an embodiment of the disclosure, the UE is operative to perform the method according to the above aspect.

According to another aspect of the disclosure, there is provided a UE with a power saving functionality. The UE comprises a processor and a memory. The memory contains instructions executable by the processor, whereby the UE is operative to send an indication that the UE supports extended router lifetime field in a Routing Advertisement message. The extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE. The UE is further operative to receive a Routing Advertisement message including the extended router lifetime field having the target value, such that the target value is used as the UE’s router lifetime.

According to another aspect of the disclosure, there is provided a SGW. The SGW comprises a processor and a memory. The memory contains instructions executable by the processor, whereby the SGW is operative to determine whether to perform message inspection for a predetermined service that can be suspended in sleeping state of a UE. The SGW is further operative to, when determining to perform message inspection, determine whether there is a redundant message buffered for the UE for the predetermined service. The SGW is further operative to, when determining that there is the redundant message, drop the redundant message.

In an embodiment of the disclosure, the SGW is operative to perform the method according to the above aspect.

According to another aspect of the disclosure, there is provided a computer program product. The computer program product comprises instructions which when executed by at least one processor, cause the at least one processor to perform the method according to the above aspect.

According to another aspect of the disclosure, there is provided a computer readable storage medium. The computer readable storage medium comprises instructions which when executed by at least one processor, cause the at least one processor to perform the method according to the above aspect.

According to another aspect of the disclosure, there is provided a PGW. The PGW comprises an obtaining module for obtaining information related to or having influence on a predetermined service that can be suspended in sleeping state of a UE. The PGW further comprises a performing module for performing the predetermined service for the UE based on the obtained information.

According to another aspect of the disclosure, there is provided a UE with a power saving functionality. The UE comprises a detection module for detecting a trigger event which is to trigger the UE to wake up from sleeping state. The UE further comprises a determination module for determining whether the trigger event is to trigger a predetermined service that can be suspended in sleeping state. The UE further comprises a keeping module for, when the trigger event is to trigger the predetermined service, keeping the UE in sleeping state. The UE further comprises a waking module for, when the trigger event is not to trigger the predetermined service, waking the UE up.

According to another aspect of the disclosure, there is provided a UE with a power saving functionality. The UE comprises a sending module for sending an indication that the UE supports extended router lifetime field in a Routing Advertisement message. The extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE. The UE further comprises a reception module for receiving a Routing Advertisement message including the extended router lifetime field having the target value, such that the target value is used as the UE’s router lifetime.

According to another aspect of the disclosure, there is provided a SGW. The SGW comprises a first determination module for determining whether to perform message inspection for a predetermined service that can be suspended in sleeping state of a UE. The SGW further comprises a second determination module for, when determining to perform message inspection, determining whether there is a redundant message buffered for the UE for the predetermined service. The SGW further comprises a dropping module for, when determining that there is the redundant message, dropping the redundant message.

Brief Description of the Drawings

These and other objects, features and advantages of the disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which are to be read in connection with the accompanying drawings.

FIG. 1 is a schematic diagram showing an exemplary wireless communication system into which an embodiment of the disclosure is applicable;

FIGs. 2A-2C are flowcharts each illustrating a method implemented at a PGW according to an embodiment of the disclosure;

FIG. 3 is a flowchart illustrating a method implemented at a UE according to an embodiment of the disclosure;

FIG. 4 is a flowchart illustrating an exemplary solution according to an embodiment of the disclosure;

FIG. 5 is a flowchart illustrating a method implemented at a SGW according to an embodiment of the disclosure;

FIG. 6 is a flowchart illustrating a method implemented at a PGW according to another embodiment of the disclosure;

FIG. 7 is a flowchart illustrating a method implemented at a UE according to another embodiment of the disclosure;

FIG. 8 is a flowchart illustrating an exemplary solution according to another embodiment of the disclosure;

FIG. 9 is a flowchart illustrating a method implemented at a PGW according to an embodiment of the disclosure; and

FIG. 10 is a block diagram showing an apparatus suitable for use in practicing some embodiments of the 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.

For Internet protocol version 6 (IPv6) CIoT devices (or UEs) , PGW is responsible for allocating IPv6 prefixes to them. Specifically, the PGW sends Router Advertisement messages periodically to the UE for Stateless Address autoconfiguration. According to request for comments (RFC) 4861 proposed by the Internet engineering task force (IETF) , the maximum value of Router Lifetime in Router Advertisement message is 65535 seconds (18.2 hours) , which means the maximum interval between two Router Advertisement messages should be less than 18.2 hours. In some cases, the Router Lifetime can be limited to 9000 seconds, i.e. 2.5 hours. From the UE’s perspective, if the expected Router Advertisement is not received before the expiry of Router Lifetime, the sleeping UE wakes up and initiates the originating service by sending a Router Solicitation message to the PGW.

For the above IPv6 CIoT device (or UE) which has enabled PSM with a potential long sleeping time, there may be problems on both UE and network side. Specifically, on the UE side, since the maximum sleeping time can be approximately 9920 hours while the maximum Router Lifetime is only 18.2 hours, the UE needs to wake up periodically in response to the expiry of Router Lifetime and send a Router Solicitation message to do Stateless Address autoconfiguration. As a result, the sleeping cycle of the UE is disrupted by the Router Lifetime which is shorter than the sleeping time.

On the network side, the PGW periodically sends unsolicited Router Advertisement messages towards the UE. These messages may be sent hundreds of times but they cannot reach the UE in sleeping state and are buffered in SGW instead. Since these messages are duplicated, it is a waste of resource to buffer all these duplicated messages and send them all to the UE after the UE is reachable.

The present disclosure proposes improved solutions which may or may not solve at least one of the above problems. Hereinafter, the solutions will be described in detail with reference to FIGs. 1-10.

FIG. 1 is a schematic diagram showing an exemplary wireless communication system into which an embodiment of the disclosure is applicable. At least part of the wireless communication system may follow any suitable communication standards, such as long term evolution (LTE) -advanced (LTE-A) , LTE, wideband code division multiple access (WCDMA) , high-speed packet access (HSPA) , and so on. Furthermore, the communications may be performed in the wireless communication system according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future.

As shown, the wireless communication system comprises a user equipment (UE) 110, a radio access network (RAN) 120, a mobility management entity (MME) 130, a serving gateway (SGW) 140 and a packet data network (PDN) gateway (PGW) 150. Note that the amount of each entity mentioned above may be more than one. The UE 110 can communicate through a radio access communication link with the RAN 120. The UE may also be referred to as, for example, mobile station, mobile unit, subscriber station, access terminal, terminal device, or the like. It may refer to any end device that can access a wireless communication network and receive services therefrom. By way of example and not limitation, the UE may include a portable computer, an image capture terminal device such as a digital camera, a gaming terminal device, a music storage and playback appliance, a mobile phone, a cellular phone, a smart phone, a tablet, a wearable device, a personal digital assistant (PDA) , or the like.

In an Internet of things (IoT) scenario, a UE 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 UE and/or a network equipment. In this case, the UE may be a machine-to-machine (M2M) device, which may, in a 3GPP context, be referred to as a machine-type communication (MTC) device. Particular examples of such machines or devices may include sensors, metering devices such as power meters, industrial machineries, or home or personal appliances, e.g. refrigerators, televisions, personal wearables such as watches, and so on.

The RAN 120 may include, for example, an universal mobile telecommunications system (UMTS) terrestrial RAN (UTRAN) , a global system for mobile communication (GSM) enhanced data rate for GSM evolution (EDGE) RAN (GERAN) , and/or an evolved universal terrestrial RAN (E-UTRAN) . The UTRAN and the GERAN can each include radio network controller (RNC) nodes to control communications through radio base stations providing radio access communication links to UEs that are within their respective communication service cells. The E-UTRAN can include radio base station nodes (evolved node Bs simply referred to as eNodeBs) that can provide the combined functionality of the RNC nodes and base stations of the UTRAN and the GERAN.

The MME 130 can route and forward signalling packets for the RAN 120. For example, the MME 130 may support functionalities such as tracking and paging procedures for idle mode UEs, authorization of UEs to camp on a service provider’s public land mobile network (PLMN) , generation and allocation of temporary identities to UEs, choosing a SGW for a UE at the initial attachment and at time of handover, enforcement of UE roaming restrictions, control plane functionality for carrying out mobility between LTE and 2G/3G access networks, or the like.

The SGW 140 can route and forward signalling and user data packets, while also acting as the mobility anchor for user plane during inter-base station/eNodeB handovers and as the anchor for mobility between LTE and other 3GPP technologies. The SGW 140 may manage and store UE communication connection contexts, which for each connection may include identification of the connection, an IP address of a packet gateway, a tunneling identifier, and a Quality of Service value.

The PGW 150 can provide entry and exit points to a packet-based network for UE traffic flowing through the SGW 140. The packet-based network may include the Internet and/or other packet network elements. A UE may have simultaneous connectivity with more than one PGW 150 for accessing multiple packet-based networks. The PGW 150 may also function as the anchor for mobility between 3GPP and non-3GPP technologies such as worldwide interoperability for microwave access (WiMAX) .

It should be noted that the MME 130, the SGW 140 and the PGW 150 are merely exemplary examples of the components in the wireless communication system and may be replaced by components with similar functionalities. For example, in 5G core (5GC) , the SGW and the PGW may be replaced by a session management function (SMF) entity, and the MME may be replaced by an access and mobility management function (AMF) entity.

FIGs. 2A-2C are flowcharts each illustrating a method implemented at a PGW according to an embodiment of the disclosure. In the first embodiment shown in FIG. 2A, at block 202, the PGW receives power saving information that indicates whether a power saving functionality is enabled for a UE. The power saving functionality may be the power saving mode (PSM) defined by 3GPP for CIoT devices. Although the embodiment is described in the context of the PSM, those skilled in the art can understand that the principle of the present disclosure may also be applied to any other similar power saving functionalities.

For example, the UE may indicate, in an Attach Request message during Attach procedure, to a corresponding MME whether the UE has enabled the power saving functionality. The MME may send the power saving information in a Create Session Request message to the PGW via a corresponding SGW. Note that the power saving information may also be indicated from the UE to the PGW in any other suitable ways as long as the PGW can obtain this information.

If the power saving information indicates that the power saving functionality is not enabled for the UE, the PGW initiates a predetermined service at a predetermined timing at block 204. The predetermined service may be any service which can be suspended in sleeping state of the UE for the purpose of avoiding unnecessary power consumption due to the initiation of such service in sleeping state of the UE. For example, the predetermined service may be an IPv6 Stateless Address autoconfiguration service for the UE. Since the power saving functionality is not enabled for the UE, the predetermined timing may be the originally configured timing for initiating the predetermined service.

On the other hand, if the power saving information indicates that the power saving functionality is enabled for the UE, the PGW sends a request for subscribing a reachability monitoring event for the UE at block 206. For example, the PGW may send an Update Bearer Request message to the MME via the SGW. If the UE is in a reachable state, the PGW will receive an Update Bearer Response message indicating that the UE is reachable immediately. This Update Bearer Response message can be used as a reachability report indicating that the UE is in a reachable state.

However, if the UE is in sleeping state, the PGW will receive an Update Bearer Response message without UE reachability indication. In this case, after the UE wakes up, the PGW will receive a Modify Bearer Request message from the MME via the SGW. This Modify Bearer Request message can be used as a reachability report indicating that the UE is in a reachable state.

At block 208, in response to receipt of the reachability report indicating that the UE is in a reachable state, the PGW initiates the predetermined service. For example, in the case of IPv6 Stateless Address autoconfiguration service for the UE, the PGW may send a Routing Advertisement message to the UE. In this way, since the PGW can initiate the predetermined service only when knowing that the UE is reachable, duplicated messages sent to the UE and thus unnecessary data buffering in the SGW can be avoided.

In the second embodiment shown in FIG. 2B, at block 202’, the PGW receives power saving information that indicates whether a power saving functionality is enabled for a UE and possible maximum sleeping time in a case where the power saving functionality is enabled for the UE. That is, compared with the first embodiment, the power saving information further indicates the possible maximum sleeping time of the UE, which may be determined by the MME based on factors such as the value proposed by the UE, the subscription data of the UE from a corresponding home subscriber server (HSS) , and so on.

Similar to the first embodiment, the MME may send the power saving information in a Create Session Request message to the PGW via the SGW. As another example, if the power saving information has been changed (for example, if it is changed by the MME after the UE enters sleeping state and then wakes up) , the PGW may receive the new power saving information in a Modify Bearer Request message from the MME via the SGW.

If the power saving information indicates that the power saving functionality is not enabled for the UE, the PGW initiates a predetermined service at a predetermined timing at block 204. This block has been described above and its details are omitted here.

If the power saving information indicates that the power saving functionality is enabled for the UE and the possible maximum sleeping time is longer than or equal to a first predetermined threshold, the PGW sends a request for subscribing a reachability monitoring event for the UE at block 206’. For example, in the case of IPv6 Stateless Address autoconfiguration service for the UE, the first predetermined threshold may be set to be equal to or greater than (e.g., equal to several times of) the Router Lifetime configured by the PGW. However, any other suitable value may also be used depending on the specific conditions of the application scenario. The subscription of the reachability monitoring event has been described above and its details are omitted here. Due to block 206’, compared with the first embodiment, unnecessary subscriptions to the reachability monitoring event can be avoided. At block 208’, in response to receipt of the reachability report indicating that the UE is in a reachable state, the PGW initiates the predetermined service. This block may be the same as block 208 and its details are omitted here.

If the power saving information indicates that the power saving functionality is enabled for the UE and the possible maximum sleeping time is shorter than the first predetermined threshold, the PGW initiates the predetermined service at a predetermined timing at block 210. Similar to block 204, the predetermined timing may be the originally configured timing for initiating the predetermined service.

The third embodiment shown in FIG. 2C shares the same blocks 202’ and 204 with the second embodiment. Thus, only the difference between these two embodiments will be described here. Specifically, if the power saving information indicates that the power saving functionality is enabled for the UE, the PGW determines a target timing according to the possible maximum sleeping time at block 212. For example, the target timing may be determined to be subsequent to the expiry of the possible maximum sleeping time. Optionally, if the possible maximum sleeping time is shorter than or equal to the time interval between the originally configured timings, the target timing may be determined as the originally configured timing. At block 214, the PGW initiates the predetermined service at the target timing. In this way, the timing for initiating the predetermined service can be adjusted dynamically based on the possible maximum sleeping time.

FIG. 3 is a flowchart illustrating a method implemented at a UE according to an embodiment of the disclosure. As shown, at block 302, a trigger event which is to trigger the UE to wake up from sleeping state is detected. The examples of the trigger event may include, but not limited to, the expiry of a specific timer, the receipt of a specific message, and so on.

At block 304, whether the trigger event is to trigger a predetermined service is determined. As described above, the predetermined service may be any service which can be suspended in sleeping state of the UE for the purpose of avoiding unnecessary power consumption due to the initiation of such service in sleeping state of the UE. For example, in the case of IPv6 Stateless Address autoconfiguration service for the UE, the corresponding trigger event is the expiry of the router lifetime configured from the PGW.

If the trigger event is to trigger the predetermined service, the UE is kept in sleeping state at block 306. On the other hand, if the trigger event is not to trigger the predetermined service, the UE is woken up at block 308. In this way, it can secure the power saving functionality to be fully used such that the power saving effect is achieved as expected. Optionally, at block 310, if a trigger event has been previously determined to trigger the predetermined service, the UE may initiate the predetermined service after the UE wakes up.

FIG. 4 is a flowchart illustrating an exemplary solution according to an embodiment of the disclosure. In this exemplary solution, the IPv6 Stateless Address autoconfiguration service for the UE is taken as the example of the predetermined service. At block 402, the UE initiates an Attach procedure by sending an Attach Request message to the MME. Within the Attach Request message, an IPv6 PDN or IPv4v6 PDN is requested.

At block 404, the MME sends a Create Session Request message to the PGW via the SGW. As described above, the Create Session Request message may include power saving information which indicates at least whether a power saving functionality is enabled for the UE. The power saving information may further indicate possible maximum sleeping time in a case where the power saving functionality is enabled for the UE.

At block 406, the PGW allocates an IPv6 prefix for the UE and also decides the Routing Advertisement parameters, such as Router Lifetime, IPv6 Prefix Valid Lifetime, and so on. At block 408, the PGW sends a Create Session Response message to the MME via the SGW. At block 410, the MME sends an Attach Accept message to the UE. The UE answers with an Attach Complete message. In the Attach Accept message, power saving parameters, such as Active Time and Periodical Tracking Area Update (TAU) timer, are provided.

Optionally, at block 412, the UE may send a Routing Solicitation message to the PGW for the purpose of Stateless Address autoconfiguration. At block 414, the PGW sends a solicited or unsolicited Routing Advertisement message to the UE for a few times in an initial period.

At block 416, the UE enters sleeping state. The method shown in FIG. 3 may be performed by the UE such that in this sleeping state, the UE will not wake up just for sending the Routing Solicitation message to the PGW.

At block 418, the method shown in FIG. 2B may be performed by the PGW such that the PGW will not directly send the unsolicited Routing Advertisement message to the UE if the PGW knows that the UE can sleep a long time. Instead, the PGW subscribes the “UE reachability” monitoring event to the MME. Specifically, the PGW sends an Update Bearer Request message to the MME via the SGW to subscribe the UE Reachability Monitoring event. Then, the PGW receives an Update Bearer Response message from the MME via the SGW.

At block 420, the UE wakes up due to other reasons, for example, the periodical TAU timer expires. At block 422, since the MME has received the “UE reachability” monitoring event from the PGW, the MME sends a Modify Bearer Request message to the PGW via the SGW for UE Reachability Report. Then, the PGW sends a Modify Bearer Response message to the MME via the SGW.

Optionally, at block 424, the UE sends a Routing Solicitation message to the PGW. At block 426, the PGW sends a solicited or unsolicited Routing Advertisement message to the UE. It should be noted that although a PGW without control plane and user plane split (CUPS) has been described above, the principle can also be equally applicable for a PGW with CUPS.

Optionally, the SGW may support message inspection, which may be implemented by performing the method shown in FIG. 5. At block 502, the SGW determines whether to perform message inspection for a predetermined service that can be suspended in sleeping state of a UE. The predetermined service has been defined above and will not be detailed here. As an option, if the SGW determines that the UE is in sleeping state, the SGW determines to perform message inspection. For example, as described above, the SGW may forward the request for subscribing a reachability monitoring event for the UE, from the PGW to the MME, and forward a reachability report indicating that the UE is in a reachable state, from the MME to the PGW. From this reachability report, the SGW can determine whether the UE is in sleeping state. It is also possible to perform this determination based on other messages such as the Create Session Request, the Create Session Response, the Routing Solicitation, and so on.

As another option, if the SGW determines that buffering duration indicated in a received Downlink Data Notification Acknowledgement (DDNA) message is longer than a second predetermined threshold, the SGW determines to perform message inspection. The second predetermined threshold may be set depending on the specific conditions of the application scenario.

If the SGW determines to perform message inspection, the SGW determines whether there is a redundant message buffered for the UE for the predetermined service at block 504. For example, in the case of IPv6 Stateless Address autoconfiguration service for the UE, the message to be inspected is a Routing Advertisement message. If the SGW determines that there is the redundant message, the SGW drops the redundant message at block 506. In this way, the waste of buffering resources can be avoided.

FIG. 6 is a flowchart illustrating a method implemented at a PGW according to another embodiment of the disclosure. At block 602, the PGW receives an indication that the UE supports extended router lifetime field in a Routing Advertisement message. The extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE. As an option, the target value may be expressed by a binary value greater than the possible maximum sleeping time of the UE. For example, the extended router lifetime field may be, for example, defined as a 32-bit unassigned integer and the unit is second, which means up to 4,294,967,295 seconds (that is, approximately 1,193,046 hours) can be set. As another option, the target value may be expressed by a specific value which is predetermined to represent infinity. For example, a specific value (e.g. FFFFFFFF) can be defined as infinity, meaning the lifetime never expires. The indication may be sent in a PDN Connectivity Request message from the UE to the MME. The MME may send this indication in a Create Session Request message to the PGW via the SGW.

At block 604, the PGW sends a Routing Advertisement message including the extended router lifetime field having the target value. With the extended router lifetime which is much longer than the UE’s sleeping time, in most cases, the UE does not need to wake up to send a Router Solicitation message in sleeping cycle.

FIG. 7 is a flowchart illustrating a method implemented at a UE according to another embodiment of the disclosure. At block 702, the UE sends an indication that the UE supports extended router lifetime field in a Routing Advertisement message. The extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE. At block 704, the UE receives a Routing Advertisement message including the extended router lifetime field having the target value, such that the target value is used as the UE’s router lifetime. Since this method corresponds to the method shown in FIG. 6, the details of

blocks

702 and 704 are omitted here.

FIG. 8 is a flowchart illustrating an exemplary solution according to another embodiment of the disclosure. At block 802, the UE initiates an IPv6 or IPv4v6 PDN connectivity setup procedure by sending a PDN Connectivity Request message to the MME. Within the message, the UE indicates the support of Extended Router Lifetime in protocol configuration option (PCO) or extended PCO (ePCO) .

At block 804, the MME sends a Create Session Request message to the PGW via the SGW. Within the message, the PCO or ePCO parameter received in the PDN Connectivity Request message is copied and included. At block 806, the PGW allocates an IPv6 prefix for the UE and also decides the Routing Advertisement parameters. Based on the indication of support of Extended Router Lifetime in the received PCO or ePCO, the PGW decides to use Extended Router Lifetime. At block 808, the PGW sends a Create Session Response message to the MME via the SGW. Within the message, the PGW indicates the support of Extended Router Lifetime in PCO or ePCO.

At block 810, the MME sends an Activate Default Evolved Packet System (EPS) Bearer Context Request message to the UE. Within the message, the PCO or ePCO parameter received in the Create Session Response message is copied and included. The UE answers with an Activate Default EPS Bearer Context Accept message.

Optionally, at block 812, the UE sends a Routing Solicitation message to the PGW for the purpose of Stateless Address autoconfiguration. At block 814, the PGW sends a solicited or unsolicited Routing Advertisement message to the UE for a few times in the initial period. Within the Routing Advertisement message, the option of Extended Router Lifetime is included.

At block 816, since both the UE and the PGW support Extended Router Lifetime and the option Extended Router Lifetime is included in the Router Advertisement message, the UE and the PGW use the Extended Router Lifetime instead of Router Lifetime as the lifetime of the PGW acting as the default Router. With the Extended Router Lifetime which is set to be much longer than the UE’s sleeping time, in most cases, the UE’s sleeping cycle can be kept without interruption from the need to send the Router Solicitation message.

FIG. 9 is a flowchart illustrating a method implemented at a PGW according to an embodiment of the disclosure. At block 902, the PGW obtains information related to or having influence on a predetermined service that can be suspended in sleeping state of a UE. For example, the information related to the predetermined service may comprise the indication that the UE supports extended router lifetime field in a Routing Advertisement message. The information having influence on the predetermined service may comprise the power saving information that indicates at least whether a power saving functionality is enabled for the UE and optionally the possible maximum sleeping time. Block 902 may be implemented as

blocks

202, 202’ and 602.

At block 904, the PGW performs the predetermined service for the UE based on the obtained information. This block may be implemented as blocks 204-208 of FIG. 2A, blocks 202’-210 of FIG. 2B and blocks 202’-214 of FIG. 2C. It should be noted that two blocks shown in succession in the above figures may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

FIG. 10 is a block diagram showing an apparatus suitable for use in practicing some embodiments of the disclosure. For example, any one of the PGW, the UE and the SGW described above may be implemented through the apparatus 1000. As shown, the apparatus 1000 may include a processor 1010, a memory 1020 that stores a program, and a communication interface 1030 for communicating data with other external devices through wired and/or wireless communication.

The program includes program instructions that, when executed by the processor 1010, enable the apparatus 1000 to operate in accordance with the embodiments of the present disclosure, as discussed above. That is, the embodiments of the present disclosure may be implemented at least in part by computer software executable by the processor 1010, or by hardware, or by a combination of software and hardware.

The memory 1020 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, flash memories, magnetic memory devices and systems, optical memory devices and systems, fixed memories and removable memories. The processor 1010 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 multi-core processor architectures, as non-limiting examples.

As another embodiment, the PGW may comprise an obtaining module and a performing module. The obtaining module may be configured to obtain information related to or having influence on a predetermined service that can be suspended in sleeping state of a UE, as described above with respect to block 902. The performing module may be configured to perform the predetermined service for the UE based on the obtained information, as described above with respect to block 904.

As another embodiment, the UE may comprise a detection module, a determination module, a keeping module and a waking module. The detection module may be configured to detect a trigger event which is to trigger the UE to wake up from sleeping state, as described above with respect to block 302. The determination module may be configured to determine whether the trigger event is to trigger a predetermined service that can be suspended in sleeping state, as described above with respect to block 304. The keeping module may be configured to, when the trigger event is to trigger the predetermined service, keep the UE in sleeping state, as described above with respect to block 306. The waking module may be configured to, when the trigger event is not to trigger the predetermined service, wake the UE up, as described above with respect to block 308.

As another embodiment, the UE may comprise a sending module and a reception module. The sending module may be configured to send an indication that the UE supports extended router lifetime field in a Routing Advertisement message, as described above with respect to block 702. The extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE. The reception module may be configured to receive a Routing Advertisement message including the extended router lifetime field having the target value, such that the target value is used as the UE’s router lifetime, as described above with respect to block 704.

As another embodiment, the SGW may comprise a first determination module, a second determination module and a dropping module. The first determination module may be configured to determine whether to perform message inspection for a predetermined service that can be suspended in sleeping state of a UE, as described above with respect to block 502. The second determination module may be configured to, when determining to perform message inspection, determine whether there is a redundant message buffered for the UE for the predetermined service, as described above with respect to block 504. The dropping module may be configured to, when determining that there is the redundant message, drop the redundant message, as described above with respect to block 506. The modules described above may be implemented by hardware, or software, or a combination of both.

In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the exemplary embodiments of this disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As such, it should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be practiced in various components such as integrated circuit chips and modules. It should thus be appreciated that the exemplary embodiments of this disclosure may be realized in an apparatus that is embodied as an integrated circuit, where the integrated circuit may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor, a digital signal processor, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this disclosure.

It should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be embodied in computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on a computer readable medium such as a hard disk, optical disk, removable storage media, solid state memory, RAM, etc. As will be appreciated by one of skill in the art, the function of the program modules may be combined or distributed as desired in various embodiments. In addition, the function may be embodied in whole or in part in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA) , and the like.

References in the present disclosure to “one embodiment” , “an embodiment” and so on, 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 implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It should be understood that, although the terms “first” , “second” and so on 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 the disclosure. 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 limit the present disclosure. 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, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. The terms “connect” , “connects” , “connecting” and/or “connected” used herein cover the direct and/or indirect connection between two elements.

The present disclosure includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. Various modifications and adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-Limiting and exemplary embodiments of this disclosure.

Claims

A method implemented at a packet data network, PDN, gateway, PGW, the method comprising:

obtaining (902) information related to or having influence on a predetermined service that can be suspended in sleeping state of a user equipment, UE; and

performing (904) the predetermined service for the UE based on the obtained information.
The method according to claim 1, wherein obtaining (902) the information comprises:

receiving (202) power saving information that indicates whether a power saving functionality is enabled for the UE; and

wherein performing (904) the predetermined service comprises:

when the power saving functionality is enabled for the UE, sending (206) a request for subscribing a reachability monitoring event for the UE; and

initiating (208) the predetermined service in response to receipt of a reachability report indicating that the UE is in a reachable state.
The method according to claim 1, wherein obtaining (902) the information comprises:

receiving (202’) power saving information that indicates whether a power saving functionality is enabled for the UE and possible maximum sleeping time in a case where the power saving functionality is enabled for the UE; and

wherein performing (904) the predetermined service comprises:

when the power saving functionality is enabled for the UE and the possible maximum sleeping time is longer than or equal to a first predetermined threshold, sending (206’) a request for subscribing a reachability monitoring event for the UE; and

initiating (208’) the predetermined service in response to receipt of a reachability report indicating that the UE is in a reachable state.
The method according to claim 3, wherein performing (904) the predetermined service comprises:

when the power saving functionality is enabled for the UE and the possible maximum sleeping time is shorter than the first predetermined threshold, initiating (210) the predetermined service at a predetermined timing.
The method according to claim 1, wherein obtaining (902) the information comprises:

receiving (202’) power saving information that indicates whether a power saving functionality is enabled for the UE and possible maximum sleeping time in a case where the power saving functionality is enabled for the UE; and

wherein performing (904) the predetermined service comprises:

when the power saving functionality is enabled for the UE, determining (212) a target timing according to the possible maximum sleeping time; and

initiating (214) the predetermined service at the target timing.
The method according to any of claims 2 to 5, wherein performing (904) the predetermined service comprises:

when the power saving functionality is not enabled for the UE, initiating (204) the predetermined service at a predetermined timing.
The method according to any of claims 2 to 6, wherein the power saving information is received in a Create Session Request message and/or a Modify Bearer Request message;

wherein the request for subscribing a reachability monitoring event is an Update Bearer Request message; and

wherein the reachability report is a Modify Bearer Request message.
The method according to any of claims 1 to 7, wherein the predetermined service is an IPv6 Stateless Address autoconfiguration service for the UE.
The method according to claim 1, wherein the predetermined service is an IPv6 Stateless Address autoconfiguration service for the UE;

wherein obtaining (902) the information comprises:

receiving (602) an indication that the UE supports extended router lifetime field in a Routing Advertisement message, wherein the extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE; and

wherein performing (904) the predetermined service comprises:

sending (604) a Routing Advertisement message including the extended router lifetime field having the target value.
The method according to claim 9, wherein the target value is expressed by a binary value greater than the possible maximum sleeping time of the UE; or

wherein the target value is expressed by a specific value which is predetermined to represent infinity.
The method according to claim 9 or 10, wherein the indication is received in a Create Session Request message.
A method implemented at a user equipment, UE, with a power saving functionality, the method comprising:

detecting (302) a trigger event which is to trigger the UE to wake up from sleeping state;

determining (304) whether the trigger event is to trigger a predetermined service that can be suspended in sleeping state;

when the trigger event is to trigger the predetermined service, keeping (306) the UE in sleeping state; and

when the trigger event is not to trigger the predetermined service, waking (308) the UE up.
The method according to claim 12, further comprising:

when a trigger event has been previously determined to trigger the predetermined service, initiating (310) the predetermined service after the UE wakes up.
The method according to claim 12 or 13, wherein the predetermined service is an IPv6 Stateless Address autoconfiguration service for the UE.
A method implemented at a user equipment, UE, with a power saving functionality, the method comprising:

sending (702) an indication that the UE supports extended router lifetime field in a Routing Advertisement message, wherein the extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE; and

receiving (704) a Routing Advertisement message including the extended router lifetime field having the target value, such that the target value is used as the UE’s router lifetime.
The method according to claim 15, wherein the target value is expressed by a binary value greater than the possible maximum sleeping time of the UE; or

wherein the target value is expressed by a specific value which is predetermined to represent infinity.
The method according to claim 15 or 16, wherein the indication is sent in a PDN Connectivity Request message.
A method implemented at a serving gateway, SGW, the method comprising:

determining (502) whether to perform message inspection for a predetermined service that can be suspended in sleeping state of a user equipment, UE;

when determining to perform message inspection, determining (504) whether there is a redundant message buffered for the UE for the predetermined service; and

when determining that there is the redundant message, dropping (506) the redundant message.
The method according to claim 18, wherein it is determined to perform message inspection when one of following events occurs:

it is determined that the UE is in sleeping state; and

it is determined that buffering duration indicated in a received Downlink Data Notification Acknowledgement (DDNA) message is longer than a second predetermined threshold.
The method according to claim 18 or 19, further comprising:

forwarding a request for subscribing a reachability monitoring event for the UE, from a packet data network, PDN, gateway, PGW, to a mobility management entity, MME; and

forwarding a reachability report indicating that the UE is in a reachable state, from the MME to the PGW.
The method according to any of claims 18 to 20, wherein the predetermined service is an IPv6 Stateless Address autoconfiguration service for the UE; and

wherein the message for the predetermined service is a Routing Advertisement message.
A packet data network, PDN, gateway, PGW (1000) , comprising:

a processor (1010) ; and

a memory (1020) , the memory (1020) containing instructions executable by the processor (1010) , whereby the PGW (1000) is operative to:

obtain information related to or having influence on a predetermined service that can be suspended in sleeping state of a user equipment, UE; and

perform the predetermined service for the UE based on the obtained information.
The PGW (1000) according to claim 22, wherein the PGW (1000) is operative to perform the method according to any of claims 2 to 11.
A user equipment, UE (1000) , with a power saving functionality, the UE (1000) comprising:

a processor (1010) ; and

a memory (1020) , the memory (1020) containing instructions executable by the processor (1010) , whereby the UE (1000) is operative to:

detect a trigger event which is to trigger the UE to wake up from sleeping state;

determine whether the trigger event is to trigger a predetermined service that can be suspended in sleeping state;

when the trigger event is to trigger the predetermined service, keep the UE in sleeping state; and

when the trigger event is not to trigger the predetermined service, wake the UE up.
The UE (1000) according to claim 24, wherein the UE (1000) is operative to perform the method according to claim 13 or 14.
A user equipment, UE (1000) , with a power saving functionality, the UE (1000) comprising:

a processor (1010) ; and

a memory (1020) , the memory (1020) containing instructions executable by the processor (1010) , whereby the UE (1000) is operative to:

send an indication that the UE supports extended router lifetime field in a Routing Advertisement message, wherein the extended router lifetime field can have a target value greater than possible maximum sleeping time of the UE; and

receive a Routing Advertisement message including the extended router lifetime field having the target value, such that the target value is used as the UE’s router lifetime
The UE (1000) according to claim 26, wherein the UE (1000) is operative to perform the method according to claim 16 or 17.
A serving gateway, SGW (1000) , comprising:

a processor (1010) ; and

a memory (1020) , the memory (1020) containing instructions executable by the processor (1010) , whereby the SGW (1000) is operative to:

determine whether to perform message inspection for a predetermined service that can be suspended in sleeping state of a user equipment, UE;

when determining to perform message inspection, determine whether there is a redundant message buffered for the UE for the predetermined service; and

when determining that there is the redundant message, drop the redundant message.
The SGW (1000) according to claim 28, wherein the SGW (1000) is operative to perform the method according to any of claims 19 to 21.