WO2017109572A1

WO2017109572A1 - Methods and devices for determining a wlan access point

Info

Publication number: WO2017109572A1
Application number: PCT/IB2016/001910
Authority: WO
Inventors: Zhi Wang; Yigang Cai
Original assignee: Alcatel Lucent
Priority date: 2015-12-22
Filing date: 2016-12-13
Publication date: 2017-06-29
Also published as: CN106912084A; CN106912084B

Abstract

An objective of the present invention is to provide methods and apparatuses for selecting a WLAN access point in LWA. According to the present invention, a WLAN access point selection policy is set in a PCRF, the WLAN access point selection policy is transmitted to the e NB in a UE attach phase, and then the e NB selects the optimal WLAN access point for the UE in LWA based on the WLAN access point selection policy. In the WLAN access point selection policy, various real-time and dynamic factors are considered. By virtue of the present invention, selection of the WLAN access point becomes more reasonable, which may meet various demands for the operators and the end users. Moreover, the present invention enables the operators not only to configure the WLAN access point selection policy based on various demands, but may also dynamically adjust the WLAN access point, thereby achieving an optimal selection of a WLAN access point in LWA.

Description

METHODS AND DEVICES FOR

DETERMINING A WLAN ACCESS POINT

TECHNICAL FIELD

[001] The present invention relates to the field of communication technology, more specifically to a LWA technology.

BACKGROUND

[002] Currently, WiFi and cellular technologies (mainly represented by LTE) have become two most successful wireless technologies. In many years, they have complemented each other with advantages. With people's increasing demands on wireless capacities, it is a good opportunity to facilitate their combination. At present, there are mainly two solutions for combining WiFi and LTE.

[003] One solution is to use LTE on unlicensed spectrum, i.e., LTE-U (LTE in Unlicensed spectrum) or LTE-LAA (LTE-Licensed Assisted Access).

[004] LTE-U or LTE-LAA is an approach of directly operating LTE on the unlicensed spectrum, which expands the LTE system from the licensed spectrum to the unlicensed spectrum. This approach uses more radio spectrum to support mobile services, such that its advantage in coverage will be lowered. [005] The other solution is to aggregate LTE and WiFi, i.e., LWA (LTE WiFi Aggregation).

[006] Fig. 1 exemplarily shows a principle diagram of LWA. As can be seen, by virtue of LWA, eNB can split LTE data payload, such that some traffic will be transmitted through WiFi, while the remaining will be transmitted over LTE per se, which therefore can significantly enhance the performance of LTE services. LWA utilizes WLAN access points to enhance LTE RAN (Radio Access Network).

[007] Although this technology, which has been strenuously promoted by Qualcomm, has some differences from LTE-U and LTE-LAA, its implementation effect is still very similar to LTE-U and LTE-LAA. [008] By virtue of LWA, WiFi operates on the unlicensed spectrum, while LTE operates on the licensed spectrum. Combination of these two wireless technologies will bring about good user experience. Both technologies may exert their advantages, and LTE is not required to perform any abnormal operations. Different from the deployment of LTE-U or LTE-AAA (this deployment requires brand-new network hardware and brand-new smart phones), LWA can be enabled by simple software upgrade.

[009] The WLAN access points may also continue supporting non-LWA traffic on an independent SSID (Service Set ID), which has more advantages than using LTE in the unlicensed spectrum. Meanwhile, it avoids drawbacks and combines advantages of the two. Therefore, LWA is a solution that will not affect the unlicensed spectrum, but can sufficiently leverage the existing WLAN access points and enhance the performance.

[010] In the existing LWA solution, when selecting a WLAN access point, the eNB only takes its signal intensity into account, ignoring other factors such as charge, load or processing capacity of related network elements, and network traffic. However, these factors are all crucial to operators and end users. For example, a user expects to select a WLAN access point charging as less as possible when selecting a WLAN access point, while for the operators, they hope that the network resources will be utilized properly and sufficiently, such that more traffic is attracted when some WLAN access points have relatively lower loads; otherwise, the use of the access point will be reduced.

[011] In view of the above, the existing LWA solution is not able to select a WLAN access point flexibly and dynamically so as to meet various demands from the operators and end users. SUMMARY

[012] An objective of the present invention is to provide methods and devices for dynamically and flexibly selecting a WLAN access point in LWA.

[013] According to a first aspect of the present invention, there is provided a method for selecting a WLAN access point in a PCRF of a LWA network, the method comprising steps of: a. receiving a session establishment request from an eNB, the session establishment request being triggered by an attach request from a UE; b. generating a WLAN access point selection policy for the UE, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for the UE in LWA; c. transmitting to the eNB a session establishment request response in which the WLAN access point selection policy is included.

[014] Preferably, the WLAN access point selection policy includes WLAN access points selectable for the UE in LWA and a priority of each of the selectable WLAN access points.

[015] Preferably, the priority is a calculation formula or a calculation rule.

[016] Preferably, the PCRF determines the priority of each of the selectable WLAN access points based on at least one of the following information: charging information of the WLAN access point; a location of the UE; a load of the eNB; a size of user data traffic; available bandwidth for a connection between the WLAN access point and the eNB; a stable state for the connection between the WLAN access point and the eNB; a historical completion situation of processing LWA traffic distribution by the WLAN access point.

[017] Preferably, the method further comprises: updating the WLAN access point selection policy based on a real-time monitoring result; notifying the eNB of the updated WLAN access point selection policy.

[018] Preferably, the WLAN access point selection policy further includes at least one of the following information: a manner of using each selectable WLAN access point; a priority of LTE; a preferred value of each selectable WLAN access point.

[019] According to a second aspect of the present invention, there is provided a method for selecting a WLAN access point in an eNB of a LWA network, the method comprising steps of: A. receiving from a PCRF a session establishment request response in which a WLAN access point selection policy is included, the session establishment request response being responsive to an attach request from a UE, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for the UE in LWA; B. transmitting to the UE a configuration message for indicating the UE to detect available WLAN access points; C. in response to a measurement report from the UE, the measurement report including the available WLAN access points detected by the UE, determining an optimal WLAN access point from the available WLAN access points detected by the UE based on the WLAN access point selection policy; D. if the optimal WLAN access point exists, dividing data to be transmitted to the UE into two parts, where one of the parts is directly transmitted to the UE via a LTE, and the other part is transmitted to the optimal WLAN access point and then transmitted to the UE by the optimal WLAN access point. [020] Preferably, the WLAN access point selection policy includes WLAN access points selectable for the UE in LWA and a priority of each of the selectable WLAN access points.

[021] Preferably, the WLAN access point selection policy further includes a priority of LTE, wherein the step of determining an optimal WLAN access point further comprises: if a priority of a WLAN access point with the highest priority is less than the priority of the LTE, determining that the optimal WLAN access point does not exist.

[022] Preferably, the priority is a calculation formula or a calculation rule, the calculation formula or the calculation rule comprising at least one of the following information: a location of the UE; a load of the eNB; a size of user data traffic; available bandwidth for a connection between the WLAN access point and the eNB; a stable state for the connection between the WLAN access point and the eNB; a historical completion situation of processing LWA traffic distribution by the WLAN access point.

[023] Preferably, the method further comprises: updating the WLAN access point selection policy based on a real-time monitoring result or a notification including the updated WLAN access point selection policy from the PCRF; and re-performing the step B to the step D based on the updated WLAN access point selection policy.

[024] According to a third aspect of the present invention, there is provided a device for selecting a WLAN access point in a PCRF of a LWA network, the device comprising: a first receiving apparatus configured to receive a session establishment request from an eNB, the session establishment request being triggered by an attach request from a UE; a policy generating apparatus configured to generate a WLAN access point selection policy for the UE, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for the UE in LWA; a first transmitting apparatus configured to transmit to the eNB a session establishment request response in which the WLAN access point selection policy is included.

[025] Preferably, the WLAN access point selection policy includes WLAN access points selectable for the UE in LWA and a priority of each of the selectable WLAN access points. [026] According to a fourth aspect of the present invention, there is provided a device for selecting a WLAN access point in an eNB of a LWA network, the device comprising: a second receiving apparatus configured to receive from a PCRF a session establishment request response in which a WLAN access point selection policy is included, the session establishment request response being responsive to an attach request from a UE, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for the UE in LWA; a second transmitting apparatus configured to transmit to the UE a configuration message for indicating the UE to detect available WLAN access points; a determining apparatus configured to, in response to a measurement report from the UE, the measurement report including the available WLAN access points detected by the UE, determine an optimal WLAN access point from the available WLAN access points detected by the UE based on the WLAN access point selection policy; a LWA implementing apparatus configured to, if the optimal WLAN access point exists, divide data to be transmitted to the UE into two parts, where one of the parts is directly transmitted to the UE via LTE, and the other part is transmitted to the optimal WLAN access point and then transmitted to the UE by the optimal WLAN access point.

[027] Preferably, the WLAN access point selection policy includes WLAN access points selectable for the UE in LWA and a priority of each of the selectable WLAN access points.

[028] Compared with the existing LWA, the present invention provides a dynamic and flexible WLAN access point selection solution in LWA. During the WLAN access point selection procedure, various dynamic factors, such as charging factor, load of related network elements, processing capacity of related network elements, and network traffic, are sufficiently considered, such that the selection of the WLAN access point becomes more reasonable, which may meet various demands for the operators and the end users. Moreover, the present invention enables the operators not only to configure the WLAN access point selection policy based on various demands, but also may dynamically adjust the WLAN access point, thereby achieving an optimal selection of a WLAN access point in LWA.

BRIEF DESCRIPTION OF THE DRAWINGS [029] Other features, objectives, and advantages of the present invention become more apparent by reading detailed description of the non-limiting embodiments with reference to the accompanying drawings:

[030] Fig. 1 shows a principle schematic diagram of LWA;

[031] Fig. 2 shows a schematic diagram of a process for determining a WLAN access point in a LWA network according to one embodiment of the present invention;

[032] Fig. 3 shows a schematic diagram of a process for determining a WLAN access point in a LWA network according to one embodiment of the present invention;

[033] Fig. 4 shows a schematic diagram of a device for determining a WLAN access point in a PCRF according to one embodiment of the present invention; [034] Fig. 5 shows a schematic diagram of a device for determining a WLAN access point in an eNB according to a further embodiment of the present invention.

[035] The same or similar reference numerals in the accompanying drawings represent the same or similar elements.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[036] The present invention achieves an objective of flexibly and dynamically selecting a WLAN access point by generating a WLAN access point selection policy in a PCRF and executing the policy by an eNB, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for a UE in LWA.

[037] Hereinafter, the present invention will be described in further detail with reference to the accompanying drawings.

[038] Fig. 2 shows a schematic diagram of a process for determining a WLAN access point in a LWA network according to one embodiment of the present invention. [039] It should be noted that the process is improvement over the UE attach procedure as specified in section 5.3.2 of 3GPP TS23.401. Fig. 2 only shows messages associated with the present invention. More message flows can be referred to section 5.3.2 of 3GPP TS 23.401 and section 7.2 of 3GPP TS23.203.

[040] The process starts from step S201. [041] In step S201, a UE 20 transmits an attach request to an eNB 21, e.g., the Attach Request message as shown in the figure.

[042] Next, in step S202, the eNB 21 transmits an attach request to a MME 22, e.g., the Attach Request message as shown in the figure.

[043] Then, in step S203 and step S204, the MME 22 transmits a create session Request to the PGW 24 via the SGW 23, e.g., the Create Session Request as shown in the figure.

[044] Next, in step S205, the PGW 24 transmits a session establishment request to the PCRF 25, e.g., the Indication of IP-CAN Session Establishment message as shown in the figure. [045] Then, in step S206, the PCRF 25 generates a WLAN access point selection policy P for the UE 20, the WLAN access point selection policy P being used to indicate the eNB 21 to determine an optimal WLAN access point for the UE 20 in LWA.

[046] The PCRF 25 may generate the WLAN access point selection policy P based on information from SPR, local configuration information, a preset rule, a network condition, and the like.

[047] In one embodiment, the WLAN access point selection policy P includes WLAN access points selectable for the UE 20 in LWA and a priority of each of the selectable WLAN access points.

[048] PCRF 25 may determine the priority of each of the selectable WLAN access points based on one or more of the following information (but not limited to the following information):

- Charging information of the WLAN access point;

Different priorities may be set based on different rates. The higher the rate of a WLAN access point is, the lower the corresponding priority is.

- Time;

Different priorities may be set for the selectable WLAN access point based on different time. For example, considering that the load of a certain WLAN access point varies over time, where the load is relatively high in daytime, while relatively low in the evening, the priority of the WLAN access point in daytime is relatively low, while the priority of this WLAN access point is relatively high in the evening.

- A location of the UE;

Different priorities may be set for the selectable WLAN access point based on the location of the UE. For example, a WLAN access point closer to the UE has a relatively high priority, while a WLAN access point distant from the UE has a relatively low priority.

- A size of the user data traffic;

Different priorities are set for the WLAN access point based on dynamic change of the UE's data traffic. For example, if the user's peak data traffic exceeds a certain set value, a higher priority is set for the WLAN access point, facilitating the LWA transmission so as to distribute traffic from the eNB. When the user's peak data traffic is lower than a certain set value, a lower priority is set for the WLAN access point, such that the data is transmitted via a LTE interface as far as possible, thereby avoiding unnecessary consumption caused by using LWA for low data traffic.

- Available bandwidth for a connection between the WLAN access point and the eNB;

When the available bandwidth for the connection between the WLAN access point and the eNB is larger than a certain threshold, a higher priority is set; otherwise, when the available bandwidth for the connection between the WLAN access point and the eNB is smaller than a certain threshold, a lower priority is set.

-A stable state for a connection between the WLAN access point and the eNB;

The more stable the connection between the WLAN access point and the eNB is, the higher the corresponding priority is.

- A historical completion situation of processing LWA traffic distribution by the WLAN access point;

It mainly refers to the processing capability of the WLAN access point, including data traffic that can be processed, the time delay, etc. If the WLAN access point has a better performance in processing the LWA traffic distribution in a past period of time, the corresponding priority will be high. For example, if the time delay of the WLAN access point in processing the distributed data is constantly higher than a certain threshold, the priority of this WLAN access point will be lowered.

[049] In one embodiment, the priority is a specific value. The PCRF 25 may determine a specific value for the priority based on the above information. In a further embodiment, the priority is a calculation formula or a calculation rule. The PCRF 25 may include the above information in the calculation formula or the calculation rule.

[050] In a further embodiment, the WLAN access point selection policy P further includes at least one of the following information:

-A manner of using each of the selectable WLAN access points;

Indicating how to use the WLAN access point, for example, that the WLAN access point is only for downlink data, for uplink data, or for both uplink and downlink data.

- A priority of LTE;

The WLAN access point selection policy P may also include a LTE priority, and the WLAN access point may be selected only when its priority is higher than the LTE priority.

In this case, the PCRF 25 may also determine the priority of each selectable WLAN access point based on the load of the eNB. Specifically, different priorities may be selected for the selectable WLAN access point based on dynamic load changes of the eNB who serves the UE. When the load of the eNB rises continuously, it means that the overhead of using LTE transmission is rising; in other words, the relative positions of the priority of the WLAN access point and the LTE priority change, and the priority of the WLAN access point relative to the LTE is increasing. In order to reflect this change, it may be set that when the load of the eNB is above a certain threshold, the priority of the selectable WLAN access point will increase by one level each time when the load rises to a certain range. For example, the initial LTE priority is 7, and the priority of the WLAN access point is 5. Since the LTE priority is higher (it will be more expensive in using the WLAN access point than using the existing LTE bearer), the WLAN access point will not be selected. In other words, the data is only transmitted via LTE, rather than LWA. However, when the load of the corresponding eNB continues rising to 75%, the priority of the WLAN access point will rise to 8. Then, this WLAN access point will be selected, and the data transmission uses the manner of LWA.

- A preferred value of each of the selectable WLAN access points;

If the priorities of two WLAN access points are identical, the WLAN access point having a higher preferred value will be selected.

[051] After the PCRF 25 generates the WLAN access point selection policy P, in step S207, the PCRF 25 transmits a session establishment request response to the PGW 24, e.g., the Acknowledge of IP-CAN Session Establish message as shown in the figure, which includes the WLAN access point selection policy P. The PCRF 25 may add a new AVP (Attribute Value Pair) in the existing Acknowledge of IP-CAN Session Establish message to carry information on the WLAN access point selection policy P.

[052] In step S208 and step S209, the PGW 24 transmits a create session response to the MME 22 via the SGW3, e.g., the Create Session Response message as shown in the figure, which includes the WLAN access point selection policy P. The information on the WLAN access point selection policy P may be carried by adding a new AVP in the existing Create Session Response message.

[053] Next, in step S210, the MME 22 transmits an attach completion message to the eNB 21, e.g., the Initial Context Setup Request or Attach Accept message as shown in the figure, which includes the information on the WLAN access point selection policy P. The information on the WLAN access point selection policy P may be carried by adding a new AVP in the existing Initial Context Setup Request or Attach Accept message.

[054] After receiving the information on the WLAN access point selection policy P, the eNB 21 will store the WLAN access point selection policy P. The eNB 21 will select, in LWA, the optimal WLAN access point for the UE 20 based on the WLAN access point selection policy P.

[055] In another embodiment, the process also further comprises step S211 (not shown in the figure) and S212 (not shown in the figure).

[056] In step S211 , the PCRF 25 updates the WLAN access point selection policy P based on a real-time monitoring result. The monitored data here may be used to determine respective parameters for the priorities of the WLAN access points. For example, if the priority of a WLAN access point is determined by the charging information, then the PCRF 25 updates the WLAN access point selection policy P based on change of the charging information of the corresponding WLAN access point.

[057] Then, in step S212, the PCRF 25 notifies the eNB 21 of the updated WLAN access point selection policy. The eNB 21 may select an optimal WLAN access point for the UE 20 in LWA based on the updated WLAN access point selection policy.

[058] Fig. 3 shows a schematic diagram of a process for determining a WLAN access point in a LWA network according to another embodiment of the present invention. [059] The process starts from step S301. It should be noted that the process refers to a LWA procedure provided by Qualcomm.

[060] In step S301, the UE 20 and the eNB 21 perform an ELS (Extended LTE Signaling) discovery procedure.

[061] In step S302, the eNB 21 queries the UE 20 about its ELS capability (i.e., the capability of supporting LWA). The UE 20 replies to the eNB 21 with indication information that it supports LWA.

[062] Then, in step S303, the eNB 21 transmits to the UE 20 a R C (Radio Resource Control) configuration request for indicating the UE 20 to detect available WLAN access points. The configuration request may include a threshold, used to indicate the UE 20 to detect WLAN access points whose energy is greater than the threshold.

[063] In step S304, the UE 20 transmits a measurement report to the eNB 21, the measurement report including the available WLAN access points detected by the UE 20. [064] Then, in step S305, the eNB 21 determines an optimal WLAN access point from the available WLAN access points detected by the UE 20 based on the WLAN access point selection policy P obtained from the PCRF 25 during the UE 20 attach procedure and stored locally.

[065] In one embodiment, the WLAN access point selection policy P includes WLAN access points selectable for the UE 20 in LWA and a priority of each of the selectable WLAN access points. The eNB 21 may determine an optimal WLAN access point based on a preset rule, for example, determine a WLAN access point with the highest priority as the optimal WLAN access point, or determine an optimal WLAN access point from the WLAN access points whose priorities are higher than a certain threshold.

[066] In one embodiment, the priority is a specific value. The eNB 21 may directly determine an optimal WLAN access point based on the value for the priority of each WLAN access point.

[067] In a further embodiment, the priority is a calculation formula or a calculation rule. The eNB 21 may first calculate the priority of each WLAN access point, and then determine an optimal WLAN access point. The calculation formula or the calculation rule may include one or more of the following information (but not limited to the following information):

- Time;

The calculation formula or the calculation rule may set different priorities for the selectable WLAN access points based on different time. For example, considering that the load of a certain WLAN access point varies over time, where the load is relatively high in daytime, while relatively low in the evening, the priority of the WLAN access point in daytime is relatively low, while the priority of the WLAN access point is relatively high in the evening.

- A location of the UE;

The calculation formula or the calculation rule may set different priorities for the selectable WLAN access points based on the location of the UE. For example, a WLAN access point closer to the UE has a relatively high priority, while a WLAN access point distant from the UE has a relatively low priority.

- A size of the user data traffic;

The calculation formula or the calculation rule may set different priorities for the WLAN access point based on dynamic change of the UE's data traffic. For example, if the user's peak data traffic exceeds a certain set value, a higher priority is set for the WLAN access point, facilitating the LWA transmission so as to distribute traffic from the eNB. When the user's peak data traffic is lower than a certain set value, a lower priority is set for the WLAN access point, such that the data is transmitted via a LTE interface as far as possible, thereby avoiding unnecessary consumption caused by using LWA for low data traffic.

The calculation formula or the calculation rule may set the priority such that: when the available bandwidth for the connection between the WLAN access point and the eNB is larger than a certain threshold, a higher priority is set; otherwise, when the available bandwidth for the connection between the WLAN access point and the eNB is smaller than a certain threshold, a lower priority is set.

-A stable state for a connection between the WLAN access point and the eNB;

The calculation formula or the calculation rule may set the priority such that the more stable the connection between the WLAN access point and the eNB is, the higher the corresponding priority is.

The calculation formula or the calculation rule may set different priorities for the WLAN access points based on the processing capabilities of the WLAN access points (including data traffic that can be processed, the time delay, etc.). If a WLAN access point has a better performance in processing LWA traffic distribution in a past period of time, the corresponding priority will be high. For example, if the time delay of the WLAN access point in processing the distributed data is constantly higher than a certain threshold, the priority of this WLAN access point will be lowered.

[068] In another embodiment, the WLAN access point selection policy P further includes the priority of the LTE. Step S305 further comprises: if the priority of a WLAN access point having the highest priority is lower than the priority of the LTE, determining that the optimal WLAN access point does not exist. When the priority of the LTE is added to the WLAN access point selection policy, only the WLAN access point whose priority is higher than the LTE priority may be selected to perform LWA. This is because the priority indicates the cost of data transmission to a certain extent. If the cost of using the WLAN access point is higher than the LTE, it will be unnecessary to employ LWA, and it is enough to employ the LTE transmission only. For example, when using charge as the basis for generating a priority, since the charge policy of the LTE will be different from that of the WLAN, the priority of the LTE will also be generated by the PCRF and carried in the WLAN access point selection policy so as to be delivered to the eNB. The WLAN access point whose priority is lower than the LTE will not be selected by the eNB, because it means that it is more expensive in using the WLAN access point than the existing LTE bearer.

[069] In this case, the calculation formula or the calculation rule of the priority may also include the load information of the eNB. Specifically, different priorities may be set for the selectable WLAN access points based on the dynamic load changes of the eNB who serves the UE. When the load of the eNB rises continuously, it means that the overheads of using LTE transmission is rising; in other words, the relative positions of the priority of the WLAN access point and the LTE priority change, and the priority of the WLAN access point relative to the LTE is rising. In order to reflect this change, it may be set that when the load of the eNB is above a certain threshold, the priority of the selectable WLAN access point will increase by one level each time when the load rises to a certain range.

[070] For example, the initial LTE priority is 7, and the priority of the WLAN access point is 5. Since the LTE priority is higher (it will be more expensive in using the WLAN access point than using the existing LTE bearer), the WLAN access point will not be selected. In other words, the data is only transmitted via LTE, rather than LWA. However, when the corresponding eNB load continues rising to 75%, the priority of the WLAN access point will rise to 8. Then, this WLAN access point will be selected, and the data transmission uses the manner of LWA. [071] In the present embodiment, the eNB 21 determines a WLAN access point 30 as the optimal WLAN access point after performing step S305.

[072] Then, in step S306, the eNB 21 establishes a bearer with the WLAN access point 30.

[073] In step S307 the eNB 21 configures the UE 20 and the WLAN access point 30 to establish a connection.

[074] Meanwhile, the data between the eNB 21 and the UE 20 are still transmitted through LTE.

[075] In step S308, the UE 20 and the WLAN access point 30 are authorized.

[076] Then, in step S309, the eNB 21 divides the data to be transmitted to the UE 20 into two parts: one of the parts is directly transmitted to the UE 20 via the LTE, while the other part is transmitted to the WLAN access point 30, which in turn transmits the part to the UE 20, thereby implementing LWA.

[077] In a further embodiment, the process further comprises step S311 (not shown in the figure) and step S312 (not shown in the figure).

[078] In step S311, the eNB 21 updates the WLAN access point selection policy P based on a real-time monitoring result or a notification including the updated WLAN access point selection policy from the PCRF. The monitored data here may be various parameters above for determining the priorities of the WLAN access points, e.g., the load of the eNB 21.

[079] In step S312, the eNB re-performs steps S303 to S309 based on the updated WLAN access point selection policy.

[080] Fig. 4 shows a schematic diagram of a device for determining a WLAN access point in the PCRF 25 according to one embodiment of the present invention. The device 400 comprises: a first receiving apparatus 401, a policy generating apparatus 402, and a first transmitting apparatus 403. [081] Hereinafter, the work process of the device 400 will be described in detail with reference to Fig. 2.

[082] First, the first receiving apparatus 401 receives a session establishment request from the UE 20, e.g., the Indication of IP-CAN Session Establishment message as shown in Fig. 2. The session establishment request is triggered by an attach request (the Attach Request shown in Fig. 2) transmitted by the UE 20.

[083] Then, the policy generating apparatus 402 generates a WLAN access point selection policy P for the UE 20, the WLAN access point selection policy P being used to indicate the eNB 21 to determine an optimal WLAN access point for the UE 20 in LWA. [084] The policy generating apparatus 402 may generate the WLAN access point selection policy P based on information from SPR, local configuration information, a preset rule, a network condition, and the like.

[085] In one embodiment, the WLAN access point selection policy P includes WLAN access points selectable for UE 20 in LWA, and a priority of each of the selectable WLAN access points. [086] The policy generating apparatus 402 may determine the priority of each of the selectable WLAN access points based on one or more of the following information (but not limited to the following information):

- Charging information of the WLAN access point;

- Time;

Different priorities may be set for the selectable WLAN access point based on different time. For example, considering that the load of a certain WLAN access point changes over time, where the load is relatively high in daytime, while relatively low in the evening, the priority of the WLAN access point in daytime is relatively low, while the priority of the WLAN access point is relatively high in the evening.

- A location of the UE;

- A size of the user data traffic;

When the available bandwidth for the connection between the WLAN access point and the eNB is larger than a certain threshold, a higher priority is set; otherwise, when the available bandwidth for the connection between the WLAN access point and the eNB is smaller than a certain threshold, a lower priority is set. - A stable state for connection between the WLAN access point and the eNB;

- A historical completion situation of processing LWA traffic distribution by the WLAN access point; It mainly refers to the processing capability of the WLAN access point, including data traffic that can be processed, the time delay, etc. If the WLAN access point has a better performance in processing LWA traffic distribution in a past period of time, the corresponding priority will be high. For example, if the time delay of the WLAN access point in processing the distributed data is constantly higher than a certain threshold, the priority of this WLAN access point will be lowered.

[087] In one embodiment, the priority is a specific value. The policy generating apparatus 402 may determine a specific value for the priority based on the above information. In a further embodiment, the priority is a calculation formula or a calculation rule. The policy generating apparatus 402 may include the above information in the calculation formula or the calculation rule.

[088] In a further embodiment, the WLAN access point selection policy P further comprises at least one of the following information:

-A manner of using each of the selectable WLAN access points;

- A priority of LTE

The WLAN access point selection policy P may also include a LTE priority, and the WLAN access point may be selected only when its priority is higher than the LTE priority. In this case, the policy generating apparatus 402 may also determine the priority of each selectable WLAN access point based on the load of eNB. Specifically, different priorities may be selected for the selectable WLAN access point based on dynamic load changes of the eNB who serves the UE. When the load of the eNB rises continuously, it means the overheads of using LTE transmission is rising; in other words, the relative positions of the priority of the WLAN access point and the LTE priority change, and the priority of the WLAN access point relative to LTE is increasing. In order to reflect this change, it may be set that when the eNB load is above a certain threshold, the priority of the selectable WLAN access point will increase by one level each time when the load rises to a certain range.

For example, the initial LTE priority is 7, and the priority of the WLAN access point is 5. Since the LTE priority is higher (it will be more expensive in using the WLAN access point than using the existing LTE bearer), the WLAN access point will not be selected. In other words, the data is only transmitted via LTE, rather than LWA. However, when the load of the corresponding eNB continues rising to 75%, the priority of the WLAN access point will rise to 8. Then, this WLAN access point is selected, and the data transmission uses the manner of LWA.

- A preferred value of each selectable WLAN access point;

[089] After the policy generating apparatus 402 generates the WLAN access point selection policy P, the first transmitting apparatus 403 transmits a session establishment request response to the PGW 24, e.g., the Acknowledge of IP-CAN Session Establish message as shown in Fig. 2, which includes the WLAN access point selection policy P. The first transmitting apparatus 403 may add a new AVP (Attribute Value Pair) in the existing Acknowledge of IP-CAN Session Establish to carry information on the WLAN access point selection policy P. The message reaches the eNB 21 via the SGW 23 and MME 22. Thus, the eNB 21 obtains the WLAN access point selection policy P generated by the PCRF 25.

[090] Fig. 5 shows a schematic diagram of a device for determining a WLAN access point in the eNB 21 according to a further embodiment of the present invention. The device 500 comprises: a second receiving apparatus 501, a second transmitting apparatus 502, a determining apparatus 503, and a LWA implementing apparatus 504.

[091] Hereinafter, the work process of the device 500 will be described in detail with reference to Figs. 2 and 3. [092] First, the second receiving apparatus 501 receives a session establishment request response from the PCRF 25, e.g., the Acknowledge of IP-CAN Session Establish message as shown in Fig. 2, which includes a WLAN access point selection policy P. The session establishment request response message is responsive to the attach request of UE 20, e.g., the Attach Request as shown in Fig. 2. The WLAN access point selection policy P is used to indicate the eNB 21 to determine an optimal WLAN access point for the UE 20 in LWA.

[093] Then, the second transmitting apparatus 502 transmits to UE 20 a RRC (Radio Resource Control) configuration request for indicating the UE 20 to detect available WLAN access points. The configuration request may include a threshold for indicating the UE 20 to detect WLAN access points whose energy is greater than the threshold.

[094] Next, the determining apparatus 503, in response to a measurement report from the UE 20, the measurement report including the available WLAN access points detected by the UE 20, determines an optimal WLAN access point from the available WLAN access points detected by the UE 20 based on the WLAN access point selection policy P obtained from the PCRF 25 during the UE 20 attach procedure and stored locally.

[095] In one embodiment, the WLAN access point selection policy P includes WLAN access points selectable for the UE 20 in LWA and a priority of each of the selectable WLAN access points. The determining apparatus 503 may determine an optimal WLAN access point based on a preset rule, for example, determine a WLAN access point with the highest priority as the optimal WLAN access point, or determine an optimal WLAN access point from the WLAN access points whose priorities are higher than a certain threshold. [096] In one embodiment, the priority is a specific value. The determining apparatus 503 may directly determine an optimal WLAN access point based on the value for the priority of each WLAN access point. [097] In a further embodiment, the priority is a calculation formula or a calculation rule. The determining apparatus 503 may first calculate the priority of each WLAN access point, and then determine an optimal WLAN access point. The calculation formula or the calculation rule may include one or more of the following information (but not limited to the following information):

- Time;

- A location of the UE;

- A size of the user data traffic;

- Available bandwidth for connection between the WLAN access point and the eNB;

-A stable state for a connection between the WLAN access point and the eNB; The calculation formula or the calculation rule may set the priority such that the more stable the connection between the WLAN access point and the eNB is, the higher the corresponding priority is.

- A historical completion situation of processing LWA traffic distribution by the WLAN access point; The calculation formula or the calculation rule may set different priorities for the

WLAN access points based on the processing capabilities of the WLAN access point (including data traffic that can be processed, the time delay, etc.). If a WLAN access point has a better performance in processing LWA traffic distribution in a past period of time, the corresponding priority will be high. For example, if the time delay of the WLAN access point in processing the distributed data is constantly higher than a certain threshold, the priority of the WLAN access point will be lowered.

[098] In another embodiment, the WLAN access point selection policy P further includes the priority of the LTE. The determining apparatus 503 may be further used to: if the priority of a WLAN access point having the highest priority is lower than the priority of LTE, determining that the optimal WLAN access point does not exist. When the priority of the LTE is added to the WLAN access point selection policy, only the WLAN access point whose priority is higher than the LTE priority may be selected to perform LWA. [099] In this case, the calculation formula or the calculation rule of the priority may also include the load information of the eNB. Specifically, different priorities may be set for the selectable WLAN access points based on the dynamic load changes of the eNB who serves the UE. When the load of the eNB rises continuously, it means the overheads of using LTE transmission is rising; in other words, the relative positions of the priority of the WLAN access point and the LTE priority change, and the priority of the WLAN access point relative to LTE is rising. In order to reflect this change, it may be set that when the load of the eNB is above a certain threshold, the priority of the selectable WLAN access point will increase by one level each time when the load rises to a certain range.

[0100] For example, the initial LTE priority is 7, and the priority of the WLAN access point is 5. Since the LTE priority is higher (it will be more expensive in using the WLAN access point than using the existing LTE bearer), the WLAN access point will not be selected. In other words, the data is only transmitted via LTE, rather than LWA. However, when the corresponding eNB load continues rising to 75%, the priority of the WLAN access point will rise to 8. Then, this WLAN access point is selected, and the data transmission uses the manner of LWA. [0101] In the present embodiment, the determining apparatus 503 determines a WLAN access point 30 as the optimal WLAN access point.

[0102] Then, the LWA implementing apparatus 504 divides the data to be transmitted to the UE 20 into two parts: one of the parts is directly transmitted to the UE 20 via the LTE, while the other part is transmitted to the WLAN access point 30 which in turn transmits the part to the UE 20, thereby implementing LWA.

[0103] It should be noted that the present invention may be implemented in software and/or a combination of software and hardware, for example, by an application-specific integrated circuit (ASIC), a general-purpose computer, or any other similar hardware device. In one embodiment, the software program of the present invention may be executed through a processor to implement the steps or functions as mentioned above. Likewise, the software program (including relevant data structures) of the present invention may be stored in a computer readable recording medium, e.g., a RAM memory, magnetic or optic driver, or soft floppy or similar devices. Additionally, some steps or functions of the present invention may be implemented by hardware, for example, a circuit cooperating with the processor so as to implement various steps or functions.

[0104] Additionally, a part of the present invention may be applied as a computer program product, e.g., computer program instructions, which, when executed by a computer, may invoke or provide a method and/or technical solution according to the present invention through operations of the computer. Further, the program instructions invoking the method of the present invention may be stored in a fixed or removable recording medium, and/or communicated through broadcast or data streams in other signal carrying media, and/or stored in a work memory of a computer device running based on the program instructions. Here, according to one embodiment of the present invention, there is provided a device that includes a memory storing the computer program instructions and a processor executing the program instructions, wherein the computer program instructions, when being executed by the processor, trigger the device to perform the method and/or technical solution according to various embodiments of the present invention as mentioned above.

[0105] It is apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention may be implemented with other embodiments without departing from the spirit or basic features of the present invention. Thus, in any way, the embodiments should be regarded as exemplary and non-limiting embodiments; and the scope of the present invention is limited by the appended claims, instead of the above description. Thus, all variations intended to fall into the meaning and scope of equivalent elements of the claims should be encompassed in the present invention. The reference signs in the claims should not be regarded as limiting the involved claims. Besides, it is apparent that the term "comprise" does not exclude other units or steps, and singularity does not exclude plurality. Various units or apparatus stated in a device claim may also be implemented by a single unit or apparatus through software or hardware. Terms such as the first and the second are used to indicate names, but not to indicate any specific sequence.

Claims

WHAT IS CLAIMED IS:

1. A method for selecting a WLAN access point in a PCRF of a LWA network, the method comprising steps of: a. receiving a session establishment request from an eNB, the session establishment request being triggered by an attach request from a UE; b. generating a WLAN access point selection policy for the UE, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for the UE in LWA; c. transmitting to the eNB a session establishment request response in which the WLAN access point selection policy is included.

2. The method according to claim 1, wherein the WLAN access point selection policy includes WLAN access points selectable for the UE in LWA and a priority of each of the selectable WLAN access points.

3. The method according to claim 2, wherein the priority is a calculation formula or a calculation rule.

4. The method according to claim 2 or 3, wherein the PCRF determines the priority of each of the selectable WLAN access points based on at least one of the following information: charging information of the WLAN access point; a location of the UE; a load of the eNB; a size of user data traffic; available bandwidth for a connection between the WLAN access point and the eNB; a stable state for the connection between the WLAN access point and the eNB; a historical completion situation of processing LWA traffic distribution by the WLAN access point.

5. The method according to claim 1 or 2 or 3, wherein the method further comprises: updating the WLAN access point selection policy based on a real-time monitoring result; notifying the eNB of the updated WLAN access point selection policy.

6. The method according to claim 2, wherein the WLAN access point selection policy further includes at least one of the following information: a manner of using each of the selectable WLAN access points; a priority of LTE; a preferred value of each of the selectable WLAN access points.

7. A method for selecting a WLAN access point in an eNB of a LWA network, the method comprising steps of:

A. receiving from a PCRF a session establishment request response in which a WLAN access point selection policy is included, the session establishment request response being responsive to an attach request from a UE, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for the UE in LWA;

B. transmitting to the UE a configuration message for indicating the UE to detect available WLAN access points;

C. in response to a measurement report from the UE, the measurement report including the available WLAN access points detected by the UE, determining an optimal WLAN access point from the available WLAN access points detected by the UE based on the WLAN access point selection policy;

D. if the optimal WLAN access point exists, dividing data to be transmitted to the UE into two parts, where one of the parts is directly transmitted to the UE via LTE, and the other part is transmitted to the optimal WLAN access point and then transmitted to the UE by the optimal WLAN access point.

8. The method according to claim 7, wherein the WLAN access point selection policy includes WLAN access points selectable for the UE in LWA and a priority of each of the selectable WLAN access points.

9. The method according to claim 8, wherein the WLAN access point selection policy further includes a priority of LTE, wherein the step of determining an optimal WLAN access point further comprises: if a priority of a WLAN access point with the highest priority is less than the priority of the LTE, determining that the optimal WLAN access point does not exist.

10. The method according to claim 8, wherein the priority is a calculation formula or a calculation rule, the calculation formula or the calculation rule including at least one of the following information: a location of the UE; a load of the eNB; a size of user data traffic; available bandwidth for a connection between the WLAN access point and the eNB; a stable state for the connection between the WLAN access point and the eNB; a historical completion situation of processing LWA traffic distribution by the WLAN access point.

11. The method according to claim 7, wherein the method further comprises: updating the WLAN access point selection policy based on a real-time monitoring result or a notification including the updated WLAN access point selection policy from the PCRF; and re-performing the step B to the step D based on the updated WLAN access point selection policy.

12. A device for selecting a WLAN access point in a PCRF of a LWA network, the device comprising: a first receiving apparatus configured to receive a session establishment request from an eNB, the session establishment request being triggered by an attach request from a UE; a policy generating apparatus configured to generate a WLAN access point selection policy for the UE, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for the UE in LWA; a first transmitting apparatus configured to transmit to the eNB a session establishment request response in which the WLAN access point selection policy is included.

13. The device according to claim 12, wherein the WLAN access point selection policy includes WLAN access points selectable for the UE in LWA and a priority of each of the selectable WLAN access points.

14. A device for selecting a WLAN access point in an eNB of a LWA network, the device comprising: a second receiving apparatus configured to receive from a PCRF a session establishment request response in which a WLAN access point selection policy is included, the session establishment request response being responsive to an attach request from a UE, the WLAN access point selection policy being used to indicate the eNB to determine an optimal WLAN access point for the UE in LWA; a second transmitting apparatus configured to transmit to the UE a configuration message for indicating the UE to detect available WLAN access points; a determining apparatus configured to, in response to a measurement report from the UE, the measurement report including the available WLAN access points detected by the UE, determine an optimal WLAN access point from the available WLAN access points detected by the UE based on the WLAN access point selection policy; a LWA implementing apparatus configured to, if the optimal WLAN access point exists, divide data to be transmitted to the UE into two parts, where one of the parts is directly transmitted to the UE via LTE, and the other part is transmitted to the optimal WLAN access point and then transmitted to the UE by the optimal WLAN access point.

15. The device according to claim 14, wherein the WLAN access point selection policy includes WLAN access points selectable for the UE in LWA and a priority of each of the selectable WLAN access points.