Network-commanded handover from WLAN to another radio access network

Abstract

Disclosed are systems and methods for providing network-directed handover of a wireless device from a wireless local area network (WLAN) to a radio access network (RAN) of another radio access technology (RAT), such as a 3rd Generation Partnership Project (3GPP) or 3rd Generation Partnership Project 2 (3GPP2) RAT. In one embodiment, a WLAN access node determines that a handover of the wireless device from the WLAN to another RAN of a different RAT is to be performed, and transmits a handover instruction to the wireless device, instructing the wireless device to perform a handover from the WLAN to the RAN of the different RAT. In this manner, the WLAN access node is able to direct the wireless device from the WLAN to the RAN of the different RAT.

Description

[0001] Related applications

[0002] This application claims the benefit of Provisional Patent Application Serial No. 61 / 811,732, filed April 13, 2013, and U.S. Patent Application Serial No. 14 / 246,841, filed April 7, 2014, the disclosures of which are hereby incorporated by reference herein in their entireties. Technical Field

[0003] The present disclosure relates to network-instructed handover of a wireless device from a wireless local area network (WLAN) to a radio access network (RAN) of another radio access technology (RAT), such as a 3rd Generation Partnership Project (3GPP) or 3rd Generation Partnership Project 2 (3GPP2) RAT. Background Art

[0004] The Institute of Electrical and Electronics Engineers (IEEE) has created and maintains a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (WLAN) communications. This set of MAC and PHY layer specifications is known as the IEEE 802.11 specifications (more specifically, IEEE Standard for Information Technology—Telecommunications and Information Exchange between Local and Metropolitan Area Networks—Specific Requirements Part 11: Wireless LAN Media Access Control (MAC) and Physical Layer (PHY) Specifications). WLANs operating according to the IEEE 802.11 specifications are also known as Wi-Fi® networks. Currently, Wi-Fi® networks primarily operate in the 2.4 GHz or 5 GHz frequency bands.

[0005] The IEEE 802.11 specification regulates the MAC layer, the PHY layer, and other aspects of each addressable unit, which is called a station (STA) (e.g., an access point or wireless device), to ensure compatibility and interoperability security between access points and wireless devices. A wireless device may also be referred to as a wireless terminal, a portable device, or a portable terminal. Wi-Fi® networks generally operate in unlicensed frequency bands. Therefore, communications on a Wi-Fi® network may be subject to interference from any number of known and unknown devices. Wi-Fi® networks are commonly used as a wireless extension to fixed / wired broadband access, for example, in residential environments and hotspots such as airports, train stations, and restaurants.

[0006] Recently, Wi-Fi® networks have seen increased interest from cellular network operators. Specifically, there has been increased interest in using Wi-Fi® networks as an extension or alternative to cellular radio access networks (RANs) to handle the ever-increasing demand for wireless bandwidth. Cellular network operators that currently serve mobile devices, such as those using any of the Third Generation Partnership Project (3GPP) technologies, view Wi-Fi® networks as a wireless technology that can provide improved service within their regular cellular networks. 3GPP technologies encompass Long Term Evolution (LTE), Universal Mobile Telecommunications System (UMTS) / Wideband Code Division Multiple Access (WCDMA), and Global System for Mobile Communications (GSM).

[0007] The term "operator-controlled Wi-Fi®" refers to Wi-Fi® deployments that are integrated at some level with a cellular network operator's existing network, where the 3GPP RAN and Wi-Fi® radio access may even connect to the same core network and provide the same services. There is currently considerable activity in the area of ​​operator-controlled Wi-Fi® within several standardization organizations. Within 3GPP, efforts are underway to connect Wi-Fi® access points to the 3GPP-specified core network. Within the Wi-Fi® Alliance (WFA), activities related to Wi-Fi® product certification are being pursued, driven in part by the need to make Wi-Fi® networks a viable wireless technology for cellular operators to support high-bandwidth offerings in their networks. In this regard, the term "Wi-Fi® offload" is often used to refer to the ability of cellular network operators to offload traffic from their cellular networks to Wi-Fi® networks, for example during peak traffic hours, and in situations where the cellular network needs to be offloaded for one reason or another, such as to provide a requested quality of service, maximize bandwidth, or simply for coverage reasons.

[0008] For cellular network operators, providing a mix of Wi-Fi® and cellular (e.g., 3GPP) radio access technologies (RATs) creates new problems. Specifically, some of these problems arise from the fact that Wi-Fi® networks and cellular networks (3GPP networks) were standardized in isolation from each other. Therefore, there is a need for intelligent mechanisms to enable coexistence of Wi-Fi® and cellular network technologies. One such area is connection management. In addition, wireless devices (e.g., LTE user equipment devices (UEs)) typically support Wi-Fi® and several 3GPP cellular technologies. However, many of these wireless devices essentially behave as two separate devices from a radio access perspective. The 3GPP RAN, as well as modems and protocols, operating in accordance with 3GPP specifications, are largely unaware of the Wi-Fi® protocols and modems operating in accordance with IEEE 802.11 specifications.

[0009] In light of the above discussion, there exists a need for systems and methods for providing intelligent connection management in communication systems having a mix of Wi-Fi® and cellular (eg, 3GPP) RATs. Summary of the Invention

[0010] Disclosed are systems and methods for network-directed handover of a wireless device from a wireless local area network (WLAN) to a radio access network (RAN) of another radio access technology (RAT), such as a 3rd Generation Partnership Project (3GPP) or 3rd Generation Partnership Project 2 (3GPP2) RAT. In one embodiment, a method of operating a WLAN access node is provided. In one embodiment, the method of operating a WLAN access node includes determining that a handover of the wireless device from the WLAN to another RAN of a different RAT is to be performed, and transmitting a handover instruction to the wireless device instructing the wireless device to perform a handover from the WLAN to the RAN of the different RAT. In this manner, the WLAN access node is able to direct the wireless device from the WLAN to the RAN of the different RAT.

[0011] In one embodiment, the handover is a selective handover. More specifically, in one embodiment, the handover is a handover of at least one but less than all communication sessions (e.g., Internet Protocol (IP) sessions) of the wireless device from the WLAN to a RAN of a different RAT. In another embodiment, the handover is a full handover. More specifically, in one embodiment, the handover is a handover of all communication sessions (e.g., IP sessions) of the wireless device from the WLAN to a RAN of a different RAT.

[0012] In one embodiment, the handover instruction is a general instruction to perform a handover from the WLAN to a RAN of a different RAT. In another embodiment, the handover instruction contains information identifying the different RAT for handover.

[0013] In yet another embodiment, the handover instruction includes information identifying a target cell in a RAN of a different RAT. Furthermore, in one embodiment, the handover instruction also includes information identifying the different RAT and the RAN of the different RAT. In another embodiment, the handover instruction also includes assistance information to assist the wireless device in performing the handover. In one embodiment, the assistance information includes at least some system information of the target cell.

[0014] In one embodiment, the different RAT is a 3GPP RAT, and the handover instruction includes one or more parameters that enable the wireless device to connect to the RAN of the 3GPP RAT.

[0015] In one embodiment, the handover instruction includes a retry timer value defining an amount of time the wireless device should attempt to access the RAN of the different RAT when performing the handover.

[0016] In one embodiment, the WLAN is an Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless network. Furthermore, in one embodiment, the different RAT is a cellular network RAT. In one embodiment, the cellular network RAT is a 3GPP or 3GPP2 RAT. Furthermore, in one embodiment, transmitting the handover instruction to the wireless device includes transmitting to the wireless device a management frame selected from the group consisting of: a deauthentication management frame including a cause code corresponding to the handover instruction; and a disassociation management frame including a cause code corresponding to the handover instruction. Furthermore, in one embodiment, transmitting the management frame further includes transmitting information about the handover instruction in one or more vendor-specific elements within the management frame. In one embodiment, the information about the handover instruction includes at least one item from the group consisting of: a target set of networks for the handover, a target RAT for the handover, a target cell, assistance information to assist the wireless device when performing the handover, and a 3GPP handover command. It should be noted that the 3GPP handover command may alternatively be referred to herein as a 3GPP handover command message. In another embodiment, the information regarding the handover instruction includes a retry timer value defining an amount of time that the wireless device should attempt to access the RAN of a 3GPP or 3GPP2 RAT when performing the handover.

[0017] In one embodiment, the WLAN is an IEEE 802.11 wireless network, the different RAT is a 3GPP or 3GPP2 cellular network RAT, and transmitting the handover instruction to the wireless device includes transmitting an association response management frame including the handover instruction to the wireless device. In another embodiment, the WLAN is an IEEE 802.11 wireless network, the different RAT is a 3GPP or 3GPP2 cellular network RAT, and transmitting the handover instruction to the wireless device includes transmitting a Basic Service Set (BSS) Transition Management frame with a zero Neighbor Report element to the wireless device. In one embodiment, transmitting the BSS Transition Management frame further includes transmitting information regarding the handover instruction in one or more vendor-specific elements within the BSS Transition Management frame. In one embodiment, the information regarding the handover instruction includes at least one item from the group consisting of: a target set of networks for handover, a target RAT for handover, a target cell, assistance information to assist the wireless device when performing the handover, and a 3GPP handover command. In another embodiment, the information regarding the handover instruction includes a retry timer value defining an amount of time the wireless device should attempt to access the RAN of the 3GPP or 3GPP2 RAT when performing the handover.

[0018] In one embodiment, the WLAN is an IEEE 802.11 wireless network, the different RAT is a 3GPP or 3GPP2 cellular network RAT, and transmitting the handover instruction to the wireless device comprises transmitting a Radio Network Management Notification (WNM Notification) request frame containing the handover instruction within one or more optional sub-elements formatted as one or more vendor-specific elements to the wireless device. In one embodiment, the handover instruction comprises at least one item selected from the group consisting of: information indicating a 3GPP or 3GPP2 RAT to handover to; a cell identifier of a target cell in a RAN of the 3GPP or 3GPP2 RAT to which the wireless device is to handover; and one or more attach parameters indicating which communication sessions of the wireless device are to be handed over.

[0019] In one embodiment, the WLAN is an IEEE 802.11 wireless network, the different RAT is a 3GPP or 3GPP2 cellular network RAT, and transmitting the handover instruction to the wireless device includes transmitting a WNM Notification Request frame including the handover instruction to the wireless device.

[0020] In one embodiment, determining to perform a handover of the wireless device from a WLAN to another RAN of a different RAT includes: deciding to initiate a handover to a 3GPP RAT; sending a handover prepare request to the RAN of the 3GPP RAT; and receiving a handover prepare response from the RAN including a 3GPP handover command. In this embodiment, transmitting the handover instruction includes transmitting a 3GPP handover command to the wireless device. Additionally, in one embodiment, transmitting the 3GPP handover command includes transmitting a frame selected from the group consisting of: a deauthorization management frame including a 3GPP handover command; a disassociation management frame including a 3GPP handover command; an association response management frame including a 3GPP handover command; a BSS transition management frame including a 3GPP handover command; and a WNM notification frame (e.g., a WNM notification request frame) including a 3GPP handover command.

[0021] In one embodiment, a WLAN access node includes a processor and a memory containing instructions executable by the processor, whereby the WLAN access node operates to: determine that a handover of a wireless device from the WLAN to another RAN of a different RAT is to be performed, and transmit a handover instruction to the wireless device instructing the wireless device to perform a handover from the WLAN to the RAN of a different RAT. The memory may include additional instructions executable by the processor, whereby the WLAN access node operates to, for example, perform any of the embodiments described above.

[0022] In another embodiment, the WLAN access node is adapted to determine that a handover of the wireless device from the WLAN to another RAN of a different RAT is to be performed, and transmit a handover instruction to the wireless device, instructing the wireless device to perform a handover from the WLAN to the RAN of a different RAT. The WLAN access node may also be adapted to perform any of the methods described above.

[0023] In another embodiment, a WLAN access node includes means for determining to perform a handover of a wireless device from the WLAN to another RAN of a different RAT and means for transmitting a handover instruction to the wireless device instructing the wireless device to perform a handover from the WLAN to the RAN of a different RAT.

[0024] In yet another embodiment, a WLAN access node includes: a WLAN communication module configured to provide WLAN communication with a wireless device; a handover decision module configured to determine that a handover of the wireless device from the WLAN to another RAN of a different RAT is to be performed; and a handover instruction module configured to transmit a handover instruction to the wireless device, instructing the wireless device to perform a handover from the WLAN to the RAN of a different RAT.

[0025] In another embodiment, a computer program is provided that includes instructions that, when executed on at least one processor, cause the at least one processor to perform any of the methods of operating a WLAN access node described above. In one embodiment, a carrier embodying the computer program is provided, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium).

[0026] In one embodiment, a method of operating a wireless device is provided, comprising: communicating with a WLAN access node; receiving a handover instruction from the WLAN access node to perform a handover from the WLAN to another RAN of a different RAT; and performing the handover in response to receiving the handover instruction.

[0027] In one embodiment, the handover instruction is an instruction for selective handover from the WLAN to another RAN of a different RAT, and performing the handover includes performing the selective handover. In another embodiment, the handover instruction is an instruction for full handover from the WLAN to another RAN of a different RAT, and performing the handover includes performing the full handover.

[0028] In one embodiment, the handover instruction is a general instruction to perform a handover to a RAN of a different RAT, and performing the handover includes performing a handover to a RAN of a different RAT. In another embodiment, the handover instruction includes information identifying a different RAT for handover, and performing the handover includes performing a handover to a RAN of a different RAT identified by the information included in the handover instruction.

[0029] In yet another embodiment, the handover instruction includes information identifying a target cell in a RAN of a different RAT, and performing the handover includes performing the handover of the target cell. In one embodiment, the handover instruction further includes information identifying the different RAT and the RAN of the different RAT. In another embodiment, the handover instruction further includes assistance information to assist the wireless device when performing the handover, and performing the handover to the target cell includes performing the handover to the target cell based on the assistance information. In one embodiment, the assistance information includes at least some system information of the target cell.

[0030] In one embodiment, the different RAT is a 3GPP RAT, and the handover instruction includes one or more parameters that enable the wireless device to connect to the RAN of the 3GPP RAT.

[0031] In one embodiment, the handover instruction includes a retry timer value defining an amount of time the wireless device should attempt to access the RAN of the different RAT when performing the handover. Additionally, in one embodiment, performing the handover includes: retrying the handover within the amount of time defined by the retry timer value; and notifying the WLAN access node of a handover failure if the handover is unsuccessful within the amount of time defined by the retry timer.

[0032] In one embodiment, the WLAN is an IEEE 802.11 wireless network. Furthermore, in one embodiment, the different RAT is a cellular network RAT. In one embodiment, the cellular network RAT is a 3GPP or 3GPP2 RAT. Furthermore, in one embodiment, receiving the handover instruction comprises receiving a management frame transmitted by the WLAN access node, wherein the management frame is selected from the group consisting of: a deauthentication management frame including a cause code corresponding to the handover instruction; and a disassociation management frame including a cause code corresponding to the handover instruction. In another embodiment, receiving the handover instruction comprises receiving an association response management frame including the handover instruction from the WLAN access node. In yet another embodiment, receiving the handover instruction comprises receiving a BSS transition management frame with a zero neighbor report element from the WLAN access node. In yet another embodiment, receiving the handover instruction comprises receiving a WNM notification frame (e.g., a WNM notification request frame) from the WLAN access node including the handover instruction within one or more optional sub-elements formatted as one or more vendor-specific elements. In yet another embodiment, receiving the handover instruction comprises receiving a WNM notification frame including the handover instruction from the WLAN access node.

[0033] In one embodiment, receiving the handover instruction includes receiving a 3GPP handover command within a WLAN frame.

[0034] In one embodiment, a wireless device is provided. In one embodiment, the wireless device includes a transceiver, a processor, and a memory containing instructions executable by the processor, whereby the wireless device operates to communicate with a WLAN access node of a WLAN via the transceiver; receive a handover instruction from the WLAN access node via the transceiver to perform a handover from the WLAN to another RAN of a different RAT; and perform the handover in response to receiving the handover instruction.

[0035] In another embodiment, the wireless device is adapted to: communicate with a WLAN access node of a WLAN; receive a handover instruction from the WLAN access node to perform a handover from the WLAN to another RAN of a different RAT; and perform the handover in response to receiving the handover instruction. The wireless device may also be adapted to perform any embodiment of the method of operating a wireless device described above.

[0036] In another embodiment, a wireless device includes: means for communicating with a WLAN access node of a WLAN; means for receiving a handover instruction from the WLAN access node to perform a handover from the WLAN to another RAN of a different RAT; and means for performing the handover in response to receiving the handover instruction.

[0037] In another embodiment, a wireless device includes: a WLAN communication module configured to provide WLAN communication with a WLAN access node of the WLAN; a handover instruction receiving module configured to receive a handover instruction from the WLAN access node to perform a handover from the WLAN to another RAN of a different RAT; and a handover module configured to perform the handover in response to the handover instruction.

[0038] In one embodiment, a computer program is provided. The computer program includes instructions that, when executed on at least one processor, cause the at least one processor to perform a method for operating a wireless device according to any of the embodiments described above. In one embodiment, a carrier embodying the computer program is provided, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium).

[0039] Those skilled in the art will appreciate the scope of the present disclosure and realize additional aspects thereof after reading the following detailed description of the embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings incorporated in and forming a part of this specification illustrate several aspects of the disclosure and together with the description serve to explain the principles of the disclosure.

[0041] Figure 1Illustrated is a communication system including a hybrid of a cellular network and a wireless local area network (WLAN) that provides network-directed handover of a wireless device from a WLAN to a cellular network according to one embodiment of the present disclosure;

[0042] Figure 2 An embodiment according to the present disclosure is shown Figure 1 The communication system performs a network-instructed handover operation of the wireless device from the WLAN to the cellular network;

[0043] Figure 3 FIG2 illustrates a frame structure of an Institute of Electrical and Electronics Engineers (IEEE) 802.11 deauthentication management frame or an IEEE 802.11 disassociation management frame used to transmit a handover instruction from a WLAN access node to a wireless device according to one embodiment of the present disclosure;

[0044] Figure 4 Another embodiment of the present disclosure is shown Figure 1 The communication system performs a network-instructed handover operation of the wireless device from the WLAN to the cellular network;

[0045] Figure 5 FIG2 illustrates a frame structure of an IEEE 802.11 association response management frame used to transmit a handover instruction from a WLAN access node to a wireless device according to another embodiment of the present disclosure;

[0046] Figures 6A to 6C The figure illustrates the frame structure of a conventional IEEE 802.11 Basic Service Set (BSS) transition management frame;

[0047] Figure 7A and 7B FIG2 illustrates a frame structure of an IEEE 802.11 BSS transition management frame used to transmit a handover instruction from a WLAN access node to a wireless device according to another embodiment of the present disclosure;

[0048] Figure 8 The figure illustrates the frame structure of the IEEE 802.11 Wireless Network Management Notification (WNM Notification) request frame;

[0049] Figure 9 FIG2 illustrates a frame structure of an IEEE 802.11 WNM Notification Request frame having a vendor-specific format used to transmit a handover instruction from a WLAN access node to a wireless device according to another embodiment of the present disclosure;

[0050] Figure 10 FIGURE 1 illustrates a frame structure of an IEEE 802.11 WNM Notification Request Action frame formatting an optional sub-element in a vendor-specific format for transmitting a Third Generation or Partnership Project (3GPP) handover command according to one embodiment of the present disclosure;

[0051] Figure 11A and 11B FIG2 illustrates a frame structure of an IEEE 802.11 WNM notification request frame used to transmit a switching instruction for multi-band operation according to another embodiment of the present disclosure;

[0052] Figure 12 According to one embodiment of the present disclosure Figure 1 A block diagram of one of the base stations of a cellular network;

[0053] Figure 13 According to one embodiment of the present disclosure Figure 1 A functional block diagram of one of the base stations of a cellular network;

[0054] Figure 14 According to one embodiment of the present disclosure Figure 1 A block diagram of a WLAN access node;

[0055] Figure 15 According to one embodiment of the present disclosure Figure 1 Functional block diagram of a WLAN access node;

[0056] Figure 16 According to one embodiment of the present disclosure Figure 1 a block diagram of one of the wireless devices; and

[0057] Figure 17 According to one embodiment of the present disclosure Figure 1 Functional block diagram of one of the wireless devices. DETAILED DESCRIPTION

[0058] The embodiments set forth below represent information that will enable those skilled in the art to practice the embodiments and illustrate the best modes for practicing the embodiments. After reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts not specifically addressed herein. It should be understood that these concepts and applications fall within the scope of the present disclosure and the appended claims.

[0059] Disclosed are systems and methods for network-directed handover of a wireless device from a wireless local area network (WLAN) to a radio access network (RAN) of another radio access technology (RAT), such as a 3rd Generation Partnership Project (3GPP) or 3rd Generation Partnership Project 2 (3GPP2) RAT. Figure 1The diagram shows a communication system 10 including a cellular RAN 12 and a WLAN 14. The cellular RAN 12 includes base stations 16-1 through 16-5 (generally referred to herein collectively as base stations 16 and individually as base stations 16) operating in accordance with a cellular RAT, such as, for example, a 3GPP or 3GPP2 RAT. Some examples of 3GPP or 3GPP2 RATs are Long Term Evolution (LTE), Universal Mobile Telecommunications System (UMTS) / Wideband Code Division Multiple Access (WCDMA), and Global System for Mobile Communications (GSM) RATs. Although five base stations 16 are shown in this example, the cellular RAN 12 may include any number of base stations 16.

[0060] WLAN 14 includes a WLAN access node 18 that operates according to a WLAN RAT and provides a connection point for WLAN 14. WLAN access node 18 may alternatively be referred to as an access point, a wireless access controller, or the like. In the embodiments described herein, the WLAN RAT is an Institute of Electrical and Electronics Engineers (IEEE) 802.11 WLAN RAT (i.e., WLAN 14 is an IEEE 802.11 or Wi-Fi® network). For example, WLAN 14 may be a Wi-Fi® hotspot. However, the present disclosure is not limited in this regard. Other WLAN RATs may be used. In one embodiment, WLAN 14 is an operator-controlled WLAN that is integrated at some level with the cellular network operator's cellular network (including cellular RAN 12). Additionally, although not shown, WLAN 14 and cellular RAN 12 may be connected to the same core network (e.g., the Evolved Packet Core (EPC) network of an LTE RAN).

[0061] Cellular RAN 12 and WLAN 14 together provide services to a number of wireless devices 20-1 through 20-5 (generally referred to herein collectively as wireless devices 20 and individually as wireless devices 20). Although five wireless devices 20 are shown in this example, there may be any number of wireless devices 20 served by cellular RAN 12 and WLAN 14. In this example, wireless devices 20-1 and 20-2 are connected to WLAN 14, while wireless devices 20-3 through 20-5 are connected to cellular RAN 12. Wireless devices 20 (which may also be referred to as wireless communication devices) may represent any suitable type of device capable of wireless communication, including, but not limited to: conventional user equipment devices (UEs) and other types of cellular phones; machine-type communication (MTC) / machine-to-machine (M2M) devices (e.g., wireless sensors or meters); radio frequency identifiers (RFIDs); WLAN terminals or stations (STAs); and laptops, tablets, and other computers with wireless capabilities.

[0062] As discussed below, the WLAN access node 18 initiates a network-directed handover of the wireless device 20-1 from the WLAN 14 to the cellular RAN 12. Using conventional techniques, the wireless device 20-1 would remain connected to the WLAN 14 until a connection to the WLAN 14 is no longer possible. Specifically, the wireless device 20-1 would remain connected to the WLAN 14 as long as the wireless device 20-1 is within the coverage area 22 of the WLAN 14. As a result, the wireless device 20-1 would remain connected to the WLAN 14 in at least some situations, although the connection to the cellular RAN 12 would be better (e.g., providing lower latency, higher data rates, etc.). According to one embodiment of the present disclosure, the WLAN access node 18 operates to initiate a handover of the wireless device 20-1 from the WLAN 14 to the cellular RAN 12 whenever such a handover is desired. As one example, when the wireless device 20-1 is greater than a predefined radio distance from the WLAN access node 18 (as indicated by dashed line 24) but still within the coverage area 22 of the WLAN 14, the WLAN access node 18 may initiate a handover from the WLAN 14 to the cellular RAN 12. As used herein, radio distance is any value (e.g., a received signal strength indicator (RSSI)) that indicates the quality or strength of a radio signal received by the wireless device 20-1 from the WLAN access node 18 or by the WLAN access node 18 from the serving device 20-1.

[0063] As discussed in detail below, to initiate a handoff of the wireless device 20-1 from the WLAN 14 to the cellular RAN 12, the WLAN access node 18 sends a handoff (HO) instruction to the wireless device 20-1. The handoff instruction may be used for a full handoff of all communication sessions (e.g., Internet Protocol (IP) sessions) from the WLAN 14 to the cellular RAN 12 or a selective handoff of one or more communication sessions, but potentially less than all communication sessions, from the WLAN 14 to the cellular RAN 12. In response to the handoff instruction, the wireless device 20-1 performs the handoff by connecting to the cellular RAN 12. In this specific example, the wireless device 20-1 connects to the base station 16-1 (more specifically, to the cell served by the base station 16-1). From that point on, the handed-off communication session is isolated from the cellular RAN 12. It is noted that although Figure 1 The embodiment of and many other embodiments described below focus on handover from WLAN 14 to cellular RAN 12, but the disclosure is not limited thereto. The handover may be from WLAN 14 to any RAN of a different RAT.

[0064] Figure 2 An embodiment according to the present disclosure is shown Figure 1The communication system 10 of FIG. 1 illustrates an operation for performing a network-directed handover of a wireless device 20-1 from a WLAN 14 to a cellular RAN 12. As illustrated, initially, communication is established between the wireless device 20-1 and the WLAN 14 via the WLAN access node 18 (step 100). At some point, the WLAN access node 18 decides or determines that a handover of the wireless device 20-1 from the WLAN 14 to a RAN of a different RAT is desired (step 102). In one embodiment, the handover is a global handover of all communications or services (e.g., all IP sessions). In another embodiment, the handover is a selective handover of specific communications or services (e.g., only certain types of IP sessions). Alternatively, the decision to perform a handover can be a general decision to perform a handover from the WLAN 14. In other words, the handover decision can be a general decision to perform a handover, wherein it is left to the wireless device 20-1 to determine the target of the handover. Alternatively, the handover decision can be a specific handover decision. More specifically, the specific handover decision may be a decision to perform handover to a target RAT (e.g., LTE), a decision to perform handover to a target RAN of the target RAT type (e.g., a specific LTE RAN), or a decision to perform handover to a target cell in a target RAN of the target RAT type (e.g., a specific cell in a specific LTE RAN).

[0065] Next, the WLAN access node 18 transmits a handover instruction to the wireless device 20-1 (step 104). As discussed in detail below, in one embodiment, the WLAN 14 is an IEEE 802.11 or Wi-Fi® network, and the handover instruction is transmitted within an IEEE 802.11 frame. The IEEE 802.11 frame may be, for example, a deauthentication management frame, a disassociation management frame, an association response management frame, a basic service set (BSS) transition management request action frame, or a wireless network management notification (WNM notification) frame (e.g., a WNM notification request frame). The handover instruction includes information indicating that a handover is to be performed. More specifically, in one embodiment, the handover instruction includes one or more of the following:

[0066] - a code indicating that a switch is to be performed (e.g., a special status code or a special reason code),

[0067] - Information indicating whether the switch is full or selective,

[0068] - information identifying the communication session to be handed over in case of selective handover (e.g. one or more 3GPP Non-Access Stratum (NAS) parameters indicating a subset of ongoing services or communication sessions (e.g. a Packet Data Network (PDN) connection identified by an Access Point Name (APN), an IP session identified by a Traffic Flow Template (TFT) to be handed over)),

[0069] - information identifying the target RAT for handover,

[0070] - information identifying the target RAN for handover,

[0071] - information identifying the target cell for handover,

[0072] - assistance information that will assist the wireless device 20-1 when performing a handover (e.g., at least some system information (SI) of the target cell),

[0073] a 3GPP handover command (which may be received by the WLAN access node 18 for handover, e.g. from the base station 16 of the target cell) or one or more parameters from the 3GPP handover command,

[0074] - one or more 3GPP NAS parameters (e.g., attach type, APN, etc.), and

[0075] - A retry time, which defines the amount of time the wireless device 20-1 should attempt to access a RAN of a different RAT (which, as discussed above, may or may not be specified by the handover instruction) when performing a handover, e.g., before notifying the WLAN access node 18 of a handover failure or attempting to reestablish handover communications with the WLAN 14.

[0076] In response to the handover instruction, the wireless device 20-1, in this example, performs a handover to the cell served by the base station 16-1 in the cellular RAN 12 (step 106). The manner in which the wireless device 20-1 performs the handover may vary depending on the specific implementation. As an example, the wireless device 20-1 synchronizes to the cell served by the base station 16-1, obtains system information for the cell (if necessary), and initiates a random access procedure to establish a connection to the cell served by the base station 16-1. Once the random access procedure is complete, the final steps of the handover are complete. The exact details then depend on the RAT of the cellular RAN 12 and the specific implementation (e.g., whether assistance information is provided in the handover instruction). Once the handover is complete, the wireless device 20-1 communicates with the base station 16-1 (step 108). In addition, if the handover is a selective handover, the wireless device 20-1 also communicates with the WLAN access node 18 for any communication sessions or services that are not being handed over (step 110).

[0077] As discussed above, in some embodiments, the handover instruction is transmitted from the WLAN access node 18 to the wireless device 20-1 within a specific type of IEEE 802.11 or Wi-Fi® frame. Figure 3The figure illustrates the frame formats of an IEEE 802.11 deauthentication management frame and an IEEE 802.11 disassociation management frame that can be used to transmit a handover instruction according to one embodiment of the present disclosure. These two frames have the same frame format. It should be noted that the frame formats of the deauthentication management frame and the disassociation management frame are defined in sections 8.3.3.12 and 8.3.3.4 of the "802.11-2012 IEEE Standard for Information technology--Telecommunications and information exchange between systems Local and metropolitan area networks--Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications," which is referred to herein as the IEEE 802.11-2012 specification.

[0078] Importantly, the frame body of the deauthentication / disassociation frame includes a reason code and one or more vendor-specific elements. In one embodiment, the handover instruction includes a special reason code transmitted in the frame body. Specifically, the IEEE 802.11-2012 specification defines several reason codes in section 8.4.1.7. In this embodiment, new reason codes are defined for handover instructions from the WLAN 14. Thus, in this embodiment, the WLAN access node 18 transmits the handover instruction by transmitting a deauthentication / disassociation management frame that includes a new or special reason code defined for indicating the handover instruction.

[0079] Furthermore, in some embodiments, the handover instruction includes additional information transmitted in one or more vendor-specific elements of the deauthentication / disassociation management frame. This additional information may include information related to the wireless device 20-1 switching from the WLAN 14 to the cellular RAN 12 (in the Figure 1 and 2 In one embodiment, the additional information includes one or more of the following:

[0080] - A target set of networks for handover (e.g., Public Land Mobile Networks (PLMNs) or Network Identifiers / System Identifiers (NIDs / SIDs) for handover). The WLAN 14 may belong to a separate network compared to the cellular RAN 12. Additionally, different equivalent PLMNs may exist in the cellular / 3GPP domain.

[0081] - Target 3GPP / 3GPP2 RAT for handover (ie, the 3GPP / 3GPP2 RAT to which the wireless device 20 - 1 should handover).

[0082] - Target 3GPP / 3GPP2 RAT and target cell for handover. This may indicate the RAT and cell to which the wireless device 20-1 should handover. The target cell may be indicated, for example, as a GSM Cell Global Identity (CGI) (comprising a Mobile Country Code (MCC), a Mobile Network Code (MNC), a Location Area Code (LAC), and a Cell Identity (CI)) or any other RAT-specific cell identifier, such as a 28-bit Universal Terrestrial Radio Access Network (UTRAN) Cell Identifier (UC-ID), comprising a Radio Network Controller Identifier (RNC-ID) and a Cell ID (C-ID). Note that the UC-ID is 28 bits, with a portion of the UC-ID used for the RNC-ID (e.g., 12 bits) and the remainder for the C-ID (e.g., 16 bits). The entire UC-ID may then identify a cell within a PLMN, and the C-ID may be used to identify a cell within a Radio Network Subsystem (RNS).

[0083] Assistance information to assist the wireless device 20-1 when performing a handover to a target cell in the target RAT. For example, the assistance information may include at least some SI elements that the wireless device 20-1 will need to read first on the target cell. When such assistance information has been provided to the wireless device 20-1 from the WLAN 14, the wireless device 20-1 may be able to access the target cell more quickly.

[0084] A 3GPP handover command as defined in the 3GPP specifications for the target RAT. For example, if the target RAT is GSM, the handover command is defined in 3GPP Technical Specification (TS) 44.018 (e.g., version 12.2.0). The same applies to UTRAN and Evolved UTRAN (E-UTRAN), where handover commands are defined in 3GPP TS 25.331 (e.g., version 12.1.0) and 36.331 (e.g., version 12.1.0), respectively. In this case, the WLAN 14 is integrated into the cellular network in such a way that it is possible to perform handover preparation phase signaling towards the RAN nodes that control / handle the target RAT and target cell. The handover command is created by the target RAN node (e.g., base station 16-1) and provided to the WLAN access node 18 for transmission to the wireless device 20-1.

[0085] - One or more 3GPP NAS parameters (eg, attach type APN, etc.).

[0086] A retry time, which indicates the amount of time the wireless device 20-1 should attempt to access the target RAT / cell in any of the situations described above. If the wireless device 20-1 is unable to access the target RAN / cell within the amount of time indicated by the retry timer, then in some embodiments, the wireless device 20-1 should attempt to abandon the access attempt to the target RAT / cell and attempt to notify the WLAN 14 (e.g., the WLAN access node 18) of the handover failure.

[0087] As discussed above, in one embodiment, the handover instruction transmitted by the WLAN access node 18 to the wireless device 20-1 may include a 3GPP handover command. Figure 4 The diagram shows a Figure 1 1. Operation of the communication system 10 in accordance with the present invention, wherein the handover instruction includes a 3GPP handover command. As illustrated, initially, communication is established between the wireless device 20-1 and the WLAN 14 via the WLAN access node 18 (step 200). In this embodiment, at some point, the WLAN access node 18 decides or determines that a handover of the wireless device 20-1 from the WLAN 14 to the cellular RAN 12 is desired (step 202). In one embodiment, the decision is a full handover. However, in another embodiment, the WLAN access node 18 may decide to initiate a full handover or a selective handover. The WLAN access node 18 then sends a handover prepare request to the base station 16-1 serving the target cell for the handover (step 204). In response, the base station 16-1 sends a handover prepare response including a 3GPP handover command to the WLAN access node 18 (step 206). It should be noted that while a 3GPP handover command is used in this example, one or more parameters normally included in a 3GPP handover command may be used instead of a full 3GPP handover command. Communications between the WLAN access node 18 and the base station 16 - 1 in steps 202 and 204 may be directly via a wired or wireless connection (eg, a cellular connection) or indirectly between the base station 16 - 1 and the WLAN access node 18 , eg, through a common core network of the cellular RAN 12 and the WLAN 14 .

[0088] Next, the WLAN access node 18 transmits a handover instruction including a 3GPP handover command to the wireless device 20-1 (step 208). As discussed above, in one embodiment, the 3GPP handover command is transmitted in an IEEE 802.11 deauthentication / disassociation management frame. However, the handover command may be transmitted in other types of IEEE 802.11 frames. In this embodiment, the handover instruction may include, for example, the 3GPP RAT type to be used for handover, the 3GPP RAT identifier (ID) to be used for handover, and one or more attach parameters in the form of a 3GPP handover command or one or more parameters normally included in a 3GPP handover command. Additionally, the handover instruction may include one or more 3GPP NAS parameters to be used in the attach request as defined in Section 5.3.2.1 of 3GPP TS 23.401 (Version 12.4.0). These parameters may include, for example, the APN, the attach type for each APN (initial attach, handover attach, handover attach with IP Flow Mobility (IFOM), etc.), the TFT, and the like.

[0089] In response to the handover instruction, which includes a 3GPP handover command, the wireless device 20-1, in this example, performs a handover to a cell served by the base station 16-1 in the cellular RAN 12 (step 210). Once the handover is complete, the wireless device 20-1 communicates with the base station 16-1 (step 212). In addition, if the handover is a selective handover, the wireless device 20-1 also communicates with the WLAN access node 18 for any communication sessions or services that are not being handed over (step 214).

[0090] As discussed above, the handover instruction may be transmitted in various types of IEEE 802.11 frames. Figure 5 、 6A 6C, 7A, 7B, and 8-10 illustrate various IEEE 802.11 frame formats that may be used to transmit a handover instruction from the WLAN access node 18 to the wireless device 20-1 according to additional embodiments of the present disclosure. More specifically, Figure 5 The figure illustrates the frame format of the IEEE 802.11 Association Response Management Frame, as defined in section 8.3.3.6 of the IEEE 802.11-2012 specification. As illustrated, the frame body of the Association Response Management Frame includes, among other elements, a Status Code element and one or more Vendor Specific Elements. In one embodiment, the Handover Instruction includes a special Status Code transmitted in the frame body, wherein the special Status Code is a new Status Code defined for Handover Instructions from the WLAN 14. Thus, in this embodiment, the WLAN access node 18 transmits the Handover Instruction by transmitting an Association Response Management Frame that includes a new or special Status Code defined for indicating a Handover Instruction.

[0091] Furthermore, in some embodiments, the handover instruction includes additional information transmitted in one or more vendor-specific elements of the association response management frame. This additional information may include information related to the wireless device 20-1 switching from the WLAN 14 to the cellular RAN 12 (in Figure 1 and 2 This legacy information may include, for example, any information described above with respect to the deauthentication / disassociation management frame.

[0092] Additionally, in another embodiment, the handover instruction may use only one or more vendor-specific elements (i.e., without any special status codes). For example, in one embodiment, the information conveyed in the one or more vendor-specific elements includes a code indicating the handover instruction. Additional information related to the handover may also be conveyed in the vendor-specific elements, as described above.

[0093] Figures 6A to 6C The figure shows the frame format of the BSS Transition Management Request frame defined in section 8.5.14.9 of the IEEE 802.11-2012 specification. Normally, the BSS Transition Management Request frame contains one or more neighbor report elements. Figure 7A and 7B As illustrated in FIG, in one embodiment, a handover instruction is transmitted from the WLAN access node 18 to the wireless device 20-1 by transmitting a BSS Transition Management Request frame with a 0 Neighbor Report element, and in particular, a BSS Transition Candidate List Entry field. This frame is then interpreted by the wireless device 20-1 as a handover instruction. More specifically, the 0 Neighbor Report element can be interpreted as indicating that there is no suitable WLAN access node to transition to, and therefore, a handover to a RAN of a different RAT (e.g., cellular RAN 12) is required. In addition, the handover instruction includes additional information related to the handover in one or more vendor-specific elements. This additional information can include, for example, any of the additional information described above with respect to the Deauthentication / Disassociation Management Frame.

[0094] Figure 8 The figure illustrates the frame format of the IEEE WNM Notification Request frame defined in section 8.5.14.28 of the IEEE 802.11-2012 specification. Importantly, the WNM Notification Request frame contains one or more optional sub-elements in which the handover instruction is transmitted from the WLAN access node 18 to the wireless device 20-1 according to one embodiment of the present disclosure. More specifically, in one embodiment, the optional sub-elements of the WNM Notification Request frame are formatted as vendor-specific elements, such as in Figure 9. Although not essential to the present disclosure, the optional sub-element may be formatted as a vendor-specific element as defined in section 8.4.2.28 of the IEEE 802.11-2012 specification. The handover instruction may then be conveyed as the vendor-specific content of the optional sub-element. As described above, the handover instruction may include code indicating handover instructions and / or information related to the desired handover (e.g., target RAT, target RAN, target cell, 3GPP handover command, 3GPP NAS parameters, retry timer, etc., or any combination thereof).

[0095] In one embodiment, the vendor-specific elements of the WNM Notification Request frame are formatted according to the Wi-Fi® Alliance (WFA) rules for this type of frame, such as Figure 10 In this embodiment, the fields of the WFA formatted vendor specific element contain the following information:

[0096] - Sub-element ID set to "221" ("Vendor Specific" as specified by the IEEE 802.11-2012 specification)

[0097] - Organization identifier set to "0x 50 6F 9A" (as requested by the WFA guidelines).

[0098] - Set to "Type" of "0x01" (along with the "WFA Technology Assignment" command).

[0099] -3GPP RAT Type indicates a handover preference regarding a specific RAT (i.e., target RAT) to be selected by the wireless device 20-1. In one embodiment, the 3GPP RAT Type field may assume the following values:

[0100] 0: Reserved

[0101] 1: Any RAT

[0102] 2: Enhanced Data Rates for Global System for Mobile Communications Global Evolution Radio Access Network (GERAN)

[0103] 3: UTRAN

[0104] 4: E-UTRAN

[0105] 5–255: Reserved

[0106] - 3GPP RAT ID specifies the ID of the target 3GPP RAN node for handover (eg the ID of the target base station 16).

[0107] Additionally, in some embodiments, the handover may be a full handover or a selective handover. In this regard, the WFA formatted vendor-specific element may optionally include one or more attachment parameters indicating a subset of ongoing services or communication sessions (e.g., IP sessions) to be switched. Examples of such attachment parameters include, but are not limited to, the APN to be switched, the attachment type for each APN (initial attachment, handover attachment, handover attachment with IFOM, etc.), a TFT indicating an n-tuple to be switched, etc., or any combination thereof. It is noted that the APN identifies the PDN with which the wireless device 20-1 communicates via the WLAN 14, such as, for example, the Internet, an IP Multimedia System (IMS) network, an enterprise network, etc. It is noted that the information discussed above may be transmitted in other types of IEEE 802.11 frames (e.g., deauthentication management frames, disassociation management frames, association request management frames, BBS transition management request action frames, etc.). Similarly, the above with respect to Figure 10 The information discussed in the WFA formatted WNM notification request frame is only one example of information included in the handover instruction. Additional or alternative information may be included in the handover instruction.

[0108] The embodiments described above focus on manipulating the wireless device 20 from the WLAN 14 to the cellular RAN 12 (or at least from the WLAN 14 to a RAN of a different RAT). Figure 11A and 11B The figure illustrates a modified IEEE 802.11 WNM Notification Request frame that can be used for multi-band manipulation according to one embodiment of the present disclosure. More specifically, the WLAN 14 may include multiple WLAN access nodes 18 operating in different frequency bands (e.g., 2.4 and 5 gigahertz (GHz) bands), or a single WLAN access node 18 operating in two or more frequency bands. Multi-band manipulation is the manipulation of a wireless device 20 from one WLAN frequency band to another WLAN frequency band. Figure 11A and 11B The WNM Notification Request frame includes the BSS Transition Management capability. Using the BSS Transition Management capability, the WNM Notification Request frame can be transmitted by the WLAN 18 to the wireless device 20-2, for example, to direct the wireless device 20-2 from one frequency band of the WLAN 14 to another frequency band of the WLAN 14.

[0109] Specific implementations of the embodiments described herein introduce mechanisms by which a WLAN access node can operate a wireless device to another RAT. Some implementations of the embodiments described above are relatively simple and can be implemented with minimal effort by network and wireless device vendors. Some implementations of the embodiments described herein also utilize elements of standardized solutions and, thus, can be implemented without excessive substantial changes to, for example, the IEEE 802.11-2012 specification.

[0110] Some implementations of the embodiments described above introduce sophisticated solutions that enable WLAN access nodes to deliver all services, full handovers, or selective handovers of only certain types of services (i.e., WLAN access nodes can deliver handovers at a desired granularity). Additionally, some implementations of the embodiments described herein provide WLAN access nodes with the ability to specify a target 3GPP RAT for handovers. Further embodiments provide enhanced WLAN multi-band manipulation that can be communicated using the same type of frames as handover instructions, requiring less implementation effort.

[0111] Although base station 16 (or any type of cellular access node) may be implemented in hardware or any combination of hardware and / or software, Figure 12 According to one embodiment of the present disclosure Figure 1 1 is a block diagram of one of the base stations 16 of FIG. 1 . It is noted that while a base station 16 is discussed herein, the functionality of the base station 16 described herein may be performed by any type of cellular access node (e.g., a RAN node, a base station, an enhanced Node B (eNodeB), a radio network controller (RNC), etc.). As illustrated, the base station 16 includes a baseband unit 26 including a processor 28, a memory 30, and a network interface 26, and a radio unit 34 including a transceiver 36 coupled to one or more antennas 38. In one embodiment, the functionality of the base station 16 described herein is implemented in software stored in the memory 30 and executed by the processor 28. Additionally, the base station 16 may include additional components responsible for providing additional functionality, including any of the functionality described above and / or any functionality necessary to support the embodiments described herein.

[0112] In one embodiment, a computer program is provided which comprises instructions which, when executed on at least one processor, causes the at least one processor to perform any of the above-described embodiments of the base station 16. In one embodiment, a carrier embodying the computer program is provided, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium).

[0113] Figure 13 According to one embodiment of the present disclosure Figure 1 As shown, the base station 16 includes a functional block diagram of one of the base stations 16. Figure 12The handover module 40 and the communication module 42 are software-implemented and executed by the processor 28 of the wireless device 20. The handover module 40 operates, for example, with the wireless device 20-1 to perform a handover of the wireless device 20-1 to a cell served by the base station 16. In addition, in some embodiments, the handover module 40 processes a handover prepare request received from the WLAN access node 18 and constructs a 3GPP handover command message as part of a handover prepare response that is sent directly or indirectly to the WLAN access node 18. Once the wireless device 20-1 is handed over to the cell served by the base station 16, the communication module 42 provides communication with the wireless device 20-1.

[0114] Although the WLAN access node 18 may be implemented using any type of hardware or any combination of hardware and software, Figure 14 According to one embodiment of the present disclosure Figure 1 4. In particular embodiments, some or all of the functionality described above provided by the WLAN access node 18 may be provided by the processor 44 executing data stored on a computer-readable medium, such as the memory 46. Alternative embodiments of the WLAN access node 18 may include additional components responsible for providing additional functionality, including any of the functionality identified above and / or any functionality necessary to support the embodiments described above.

[0115] In one embodiment, a computer program is provided that includes instructions that, when executed on at least one processor, cause the at least one processor to perform any of the above-described embodiments of the WLAN access node 18. In one embodiment, a carrier embodying the computer program is provided, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium).

[0116] Figure 15 According to one embodiment of the present disclosure Figure 1 1 . A functional block diagram of a WLAN access node 18 is shown. As shown, the WLAN access node 18 includes a WLAN communication module 52, a handover decision module 54, and a handover instruction module 56, each of which is implemented in software that is executed by one or more processors of the WLAN access node 18 to provide the functionality described herein. The WLAN communication module 52 provides for communication with wireless devices 20 connected to the WLAN 14. The handover decision module 54 determines when to perform a handover of the wireless device 20 from the WLAN 14 to another RAT. The handover instruction module 56 provides handover instructions to the wireless device 20 when appropriate. Although not shown, the WLAN access node 18 may include additional modules, such as, for example, a communication module for communicating to and / or from the cellular RAN 12 (e.g., to and / or from the base stations 16 in the cellular RAN 12, e.g., directly or via a public core network).

[0117] Although wireless device 20 may be implemented in any type of hardware or any combination of hardware and software, Figure 16 According to one embodiment of the present disclosure Figure 1 6 is a block diagram of one of the wireless devices 20. As illustrated, the wireless device 20 includes a processor 58, a memory 60, and a transceiver 62 coupled to one or more antennas 64. In particular embodiments, some or all of the functionality described above provided by the wireless device 20 may be provided by the processor 58 executing instructions stored on a computer-readable medium, such as the memory 60. Alternative embodiments of the wireless device 20 may include additional components responsible for providing additional functionality, including any of the functionality identified above and / or any functionality necessary to support the embodiments described above.

[0118] In one embodiment, a computer program is provided that includes instructions that, when executed on at least one processor, cause the at least one processor to perform any of the embodiments of the wireless device 20 described above. In one embodiment, a carrier embodying the computer program is provided, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium).

[0119] Figure 17 According to one embodiment of the present disclosure Figure 1 1 . A functional block diagram of one of the wireless devices 20 of FIG. 1 is shown. As illustrated, the wireless device 20 includes a WLAN communication module 66, a handover instruction receiving module 68, a handover module 70, and a cellular network communication module 72, each of which is implemented in software that is executed by one or more processors of the wireless device 20 to provide the functionality described herein. The WLAN communication module 66 provides for communication with the WLAN access node 18 of the WLAN 14. The handover instruction receiving module 68 operates to receive a handover instruction from the WLAN access node 18. When the handover instruction receiving module 68 receives the handover instruction, the handover module 70 operates to perform a handover from the WLAN 14 to another RAT (e.g., the 3GPP RAT of the cellular RAN 12). The cellular network communication module 72 provides for communication with the cellular RAN 12.

[0120] The following acronyms are used throughout this disclosure:

[0121] 3GPP Third Generation Partnership Project

[0122] 3GPP2 Third Generation Partnership Project 2

[0123] APN Access Point Name

[0124] BSS Basic Service Set

[0125] CGI Community Global Identity

[0126] CI Community Identity

[0127] C-Id Cell identifier

[0128] eNodeB Evolved Universal Terrestrial Radio Access Network NodeB

[0129] EPC Evolved Packet Core

[0130] E-UTRAN Evolved Universal Terrestrial Radio Access Network

[0131] GERAN Global System for Mobile Communications Enhanced Data Rates for Global Evolution Radio Access Network

[0132] GHz Gigahertz

[0133] GSM Global System for Mobile Communications

[0134] HO Handover

[0135] ID identifier

[0136] IEEE Institute of Electrical and Electronics Engineers

[0137] IFOM Internet Protocol Flow Mobility

[0138] IMS Internet Protocol Multimedia System

[0139] IP Internet Protocol

[0140] LAC Location Area Code

[0141] LTE Long Term Evolution

[0142] M2M Machine to Machine

[0143] MAC Media Access Control

[0144] MCC Mobile Country Code

[0145] MNC Mobile Network Code

[0146] MTC Machine Type Communication

[0147] NAS Non-Access Stratum

[0148] NID Network Identifier

[0149] PDN Packet Data Network

[0150] PHY Physical Layer

[0151] PLMN Public Land Mobile Network

[0152] RAN Radio Access Network

[0153] RAT Radio Access Technology

[0154] RFID Radio Frequency Identifier

[0155] RNC Radio Network Controller

[0156] RNC-ID Radio Network Controller Identifier

[0157] RNS Radio Network Subsystem

[0158] RSSI Received Signal Strength Indicator

[0159] SI System Information

[0160] SID System Identifier

[0161] STA Station

[0162] TFT business flow template

[0163] TS Technical Specification

[0164] UC-Id Universal Terrestrial Radio Access Network Cell Identifier

[0165] UE User Equipment

[0166] UMTS Universal Mobile Telecommunications System

[0167] UTRAN Universal Terrestrial Radio Access Network

[0168] WCDMA Wideband Code Division Multiple Access

[0169] WFA Wi-Fi® Alliance

[0170] LAN Wireless Local Area Network

[0171] WNM-Notification Wireless Network Management Notification.

[0172] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure, and all such improvements and modifications are considered to be within the scope of the concepts disclosed herein and the claims that follow.

Claims

1. A method for operating a wireless local access network (WLAN) access node, comprising: Deciding to perform a handover of the wireless device from the WLAN to another radio access network of a different radio access technology; as well as transmitting a handover instruction to the wireless device, the handover instruction directing the wireless device to perform a handover from the WLAN to a radio access network of a different radio access technology, wherein the different radio access technology is a Third Generation Partnership Project (3GPP) radio access technology, and wherein the handover instruction includes information indicating whether the handover is a full handover or a selective handover, wherein the WLAN is capable of performing both full and selective handovers, The transmitting of the handover instruction to the wireless device comprises transmitting a basic service set (BSS) transition management frame with a zero neighbor report element to the wireless device, the transition management frame being interpreted by the wireless device as the handover instruction. The method of claim 1 , wherein the switching is selective switching. The method of claim 1 , wherein the handover is a full handover.

4. The method of claim 1, wherein the handover instruction is a general instruction to perform a handover to a radio access network of a different radio access technology.

5. The method of claim 1, wherein the handover instruction includes information identifying the different radio access technology to be used for the handover.

6. The method of claim 1, wherein the handover instruction comprises information identifying a target cell in the radio access network of the different radio access technology. 7 . The method of claim 6 , wherein the handover instruction further comprises information identifying the different radio access technology and the radio access network of the different radio access technology.

8. The method of claim 6, wherein the handover instruction further includes assistance information to assist the wireless device when performing the handover.

9. The method of claim 8, wherein the assistance information includes at least some system information of the target cell.

10. The method of claim 1, the handover instruction comprising one or more parameters that enable the wireless device to connect to the radio access network of the 3GPP radio access technology.

11. The method of claim 1 , wherein the handover instruction includes a retry timer value defining an amount of time the wireless device should attempt to access the radio access network of the different radio access technology when performing the handover.

12. The method of claim 1, wherein the WLAN is an IEEE 802.11 wireless network.

13. The method of claim 12, wherein the different radio access technology is a cellular network radio access technology.

14. The method of claim 13, wherein the 3GPP cellular network radio access technology is a 3rd Generation Partnership Project 2 (3GPP2) radio access technology.

15. The method of claim 14, wherein transmitting the handover instruction to the wireless device comprises transmitting a management frame selected from the group consisting of: a deauthentication management frame including a reason code corresponding to the handover instruction; and A disassociation management frame includes a cause code corresponding to the handover instruction.

16. The method of claim 15, wherein transmitting the management frame further comprises transmitting information about the handover instruction in one or more vendor specific elements within the management frame.

17. The method of claim 16, wherein the information about the switching instruction comprises at least one item from the group consisting of: a target set of networks for said switching; a target radio access technology for the handover; Target cell; assistance information to assist the wireless device when performing the handover; 3GPP Handover Command; and Non-access stratum (NAS) parameters.

18. The method of claim 16, wherein the information about the handover instruction includes a retry timer value defining an amount of time the wireless device should attempt to access the radio access network of the 3GPP or 3GPP2 radio access technology when performing the handover.

19. The method of claim 14, wherein transmitting the handover instruction to the wireless device comprises transmitting an association response management frame including the handover instruction to the wireless device.

20. The method of claim 1, wherein transmitting the BSS transition management frame further comprises transmitting information about the switching instruction in one or more vendor specific elements within the BSS transition management frame.

21. The method of claim 20, wherein the information about the switching instruction comprises at least one item from the group consisting of: a target set of networks for said switching; a target radio access technology for the handover; Target cell; assistance information to assist the wireless device when performing the handover; 3GPP Handover Command; and Non-access stratum (NAS) parameters.

22. The method of claim 20, wherein the information about the handover instruction includes a retry timer value defining an amount of time the wireless device should attempt to access the radio access network of the 3GPP or 3GPP2 radio access technology when performing the handover.

23. The method of claim 14, wherein transmitting the handover instruction to the wireless device comprises: A wireless network management notification (WNM notification request) frame including the handover instruction within one or more optional sub-elements formatted as one or more vendor specific elements is transmitted to the wireless device.

24. The method of claim 23, wherein the handover instruction comprises at least one of the group consisting of: information indicating the 3GPP or 3GPP2 radio access technology to be used for the handover; a cell identifier of a target cell in the radio access network of the 3GPP or 3GPP2 radio access technology to which the wireless device is to handover; and One or more attach parameters indicating which communication sessions of the wireless device are to be handed over.

25. The method of claim 14, wherein transmitting the handover instruction to the wireless device comprises transmitting a wireless network management notification (WNM notification request) frame including the handover instruction to the wireless device.

26. The method of claim 1, wherein: Deciding to perform a handover of the wireless device from the WLAN to another radio access network of a different radio access technology includes: - deciding to initiate a handover to said 3rd Generation Partnership Project 3GPP radio access technology; - sending a handover prepare request to a radio access node in a radio access network of the 3GPP radio access technology; and - receiving a handover preparation response including a 3GPP handover command from the radio access node; and Transmitting the handover instruction includes transmitting the 3GPP handover command to the wireless device.

27. The method of claim 26, wherein transmitting the handover instruction comprises transmitting a frame selected from the group consisting of: a deauthorization management frame including the 3GPP handover command; A disassociation management frame including the 3GPP handover command; An association response management frame including the 3GPP handover command; A basic service set (BSS) transition management frame including the 3GPP handover command; as well as A radio network management notification (WNM) notification request frame including the 3GPP handover command.

28. A wireless local access network (WLAN) access node, comprising: processor; as well as A memory containing instructions executable by the processor, whereby the WLAN access node is operable to perform the method according to any one of claims 1-27.

29. A method of operating a wireless device, comprising: Communicate with a wireless local access network WLAN access node; receiving a handover instruction from the WLAN access node to perform a handover from the WLAN to another radio access network of a different radio access technology, the handover instruction being determined by the WLAN access node; as well as performing the handover in response to receiving the handover instruction, wherein the different radio access technology is a 3rd Generation Partnership Project (3GPP) radio access technology, and wherein the handover instruction includes information indicating whether the handover is a full handover or a selective handover, and wherein the wireless device is capable of performing both a full handover and a selective handover, Receiving the handover instruction includes receiving a basic service set (BSS) transition management frame with a zero neighbor report element from the WLAN access node, wherein the wireless device interprets the transition management frame as the handover instruction.

30. The method of claim 29, wherein the handover instruction is an instruction for selective handover from the WLAN to another radio access network of a different radio access technology, and performing the handover comprises performing the selective handover.

31. The method of claim 29, wherein the handover instruction is an instruction for a full handover from the WLAN to another radio access network of a different radio access technology, and performing the handover comprises performing the full handover.

32. The method of claim 29, wherein the handover instruction is a general instruction to perform a handover to a radio access network of a different radio access technology, and performing the handover comprises performing the handover to a radio access network of a different radio access technology.

33. The method of claim 29, wherein the handover instruction includes information identifying the different radio access technology for the handover, and performing the handover includes performing the handover to a radio access network of the different radio access technology identified by the information included in the handover instruction.

34. The method of claim 29, wherein the handover instruction comprises information identifying a target cell in the radio access network of the different radio access technology, and performing the handover comprises performing the handover to the target cell.

35. The method of claim 34, wherein the handover instruction further comprises information identifying the different radio access technology and the radio access network of the different radio access technology.

36. The method of claim 34, wherein the handover instruction further includes assistance information to assist the wireless device when performing the handover, and performing the handover to the target cell comprises performing the handover to the target cell based on the assistance information.

37. The method of claim 36, wherein the assistance information includes at least some system information of the target cell.

38. The method of claim 29, wherein the handover instruction comprises one or more parameters that enable the wireless device to connect to the radio access network of the 3GPP radio access technology.

39. The method of claim 29, wherein the handover instructions include a retry timer value defining an amount of time the wireless device should attempt to access the radio access network of the different radio access technology when performing the handover.

40. The method of claim 39, wherein: performing the handover includes retrying the handover within the amount of time defined by the retry timer value; as well as If the handover is unsuccessful within the amount of time defined by the retry timer, the WLAN access node is notified of a handover failure.

41. The method of claim 29, wherein the WLAN is an IEEE 802.11 wireless network.

42. The method of claim 41, wherein the different radio access technology is a cellular network radio access technology.

43. The method of claim 42, wherein the 3GPP cellular network radio access technology is a 3rd Generation Partnership Project 2 (3GPP2) radio access technology.

44. The method of claim 43, wherein receiving the handover instruction comprises receiving a management frame transmitted by the WLAN access node, the management frame selected from the group consisting of: a deauthentication management frame including a reason code corresponding to the handover instruction; and A disassociation management frame includes a cause code corresponding to the handover instruction.

45. The method of claim 43, wherein receiving the handover instruction comprises receiving an association response management frame including the handover instruction from the WLAN access node.

46. ​​The method of claim 43, wherein receiving the handover instruction comprises receiving a Wireless Network Management Notification (WNM) notification request frame from the WLAN access node that includes the handover instruction within one or more optional sub-elements formatted as one or more vendor specific elements.

47. The method of claim 43, wherein receiving the handover instruction comprises receiving a wireless network management notification (WNM notification) frame including the handover instruction from the WLAN access node.

48. The method of claim 29, wherein receiving the handover instruction comprises receiving a Third Generation Partnership Project (3GPP) handover command within a WLAN frame.

49. A wireless device comprising: transceiver; processor; as well as A memory containing instructions executable by the processor, whereby the wireless device is operable to perform the method of any one of claims 29-48.

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