[0001] Wireless mobile communication networks by which wireless mobile devices such as smartphones can communicate wirelessly have greatly increased in popularity. Such wireless mobile communication networks provide for both voice and data communication. Traditionally, these two types of communication were separate. More recently, with the advent of voice-over- Internet protocol (VoIP) technologies, voice communication has been merged with data communication, where voice is considered as just another type of data communication.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 is a diagram of an example wireless mobile communication network and wireless local-area network (WLAN) architecture.

[0003] FIG. 2 is a flowchart of an example method for providing seamless integration between a WLAN and a wireless mobile communication network when voice communication is terminated.

[0004] FIG. 3 is a diagram of an example server for providing seamless integration between a WLAN and a wireless mobile communication network when voice communication is terminated. DETAILED DESCRIPTION

[0005] As noted in the background, although traditionally wireless mobile communication networks treated voice communication separately from data communication, more recently voice communication is being treated as just another type of data communication. For example, wireless mobile

communication networks employing second generation (2G) and third generation (3G) protocols typically treat voice communication in a circuit-switching manner akin to wired public switched telephone networks (PSTNs), and treat data communication in a packet-switching manner similar to Internet protocol (IP)-type networks like the Internet. However, newer fourth generation (4G) data transmission protocols such as long-term evolution (LTE) permit voice

communication to be treated as data, using voice-over-Internet protocol (VoIP) technologies, specifically voice-over-LTE (VoLTE) technologies.

[0006] As such, wireless mobile communication networks have been upgraded to support VoLTE technologies, permitting voice communication using both traditional packet-switching approaches provided by the 2G/3G protocol as well as packet-switching approaches that 4G protocols like LTE permit. (The terminology "2G/3G" protocol is used herein to specify just the 2G protocol, just the 3G protocol, or both the 2G and 3G protocols.) One advantage of providing voice communication in a packet-switching manner is greater efficiency in network resource utilization as compared to providing such voice communication in a circuit-switching manner. [0007] Packet-switching approaches for supporting voice communication in wireless mobile communication networks, such as VoLTE, can be likened to VoIP technologies that have already proven popular as a lower cost and more flexible alternative to traditional landline PSTN technologies by moving voice communications from a PSTN and onto the Internet. With the advent of wireless local-area network (WLAN) technologies such as Wi-Fi, VoIP in context of WLAN - i.e., voice-over-WLAN (VoWLAN) such as voice over Wi-Fi (VoWiFi) - has also been shown to be feasible. VoWLAN technologies have a decided cost advantage in expanding coverage areas over VoLTE technologies that rely upon mobile communication networks: in general, it is usually cheaper and faster to add Wi-Fi "hot spots" than it is to add mobile communication network towers and antennas.

[0008] The desirable outcome is for seamless integration between WLANs and mobile communication networks. For example, a user of a smartphone might connect to a Wi-Fi network, and when he or she travels out of range, be automatically switched over to a mobile communication network using a 4G protocol or the 2G/3G protocol. If a user is currently on a phone call using VoWLAN when he or she moves out of range, the user may be switched over to VoLTE automatically, for instance, without the phone call dropping out. In this way, WLAN technologies can supplement existing mobile communication networks, or even supplant them, with existing networks using a 4G or the 2G/3G protocol serving as secondary networks where a WLAN hot spot is unavailable. [0009] However, existing mobile communication network technologies do not currently support such seamless integration with WLANs. For example, when a user of a smartphone is called using his or her phone number, the access domain to which the smartphone is currently connected (i.e., attached) is determined so that the phone call can terminate (i.e., connect to) to the user's smartphone. The terminology "access domain" refers to the protocol and/or the underlying infrastructure by which the smartphone communicates. Current technologies specify the access domain as being a type of third generation partnership project (3GPP) access domain: either a 4G-type domain that may be supported by a network device known as a mobile management entity (MME), or a 2G/3G-type domain that may be supported by a serving general packet radio service (GPRS) support node (SGSN). When the user moves within a "cell" supported by an MME or an SGSN, the smartphone registers with the MME or the SGSN to become attached to the corresponding access domain.

[0010] VoWLAN, by comparison, involves the user's smartphone being attached to a non-3GPP access domain not supported by existing mobile communication network technologies, specifically a VoWLAN-type non-3GPP access domain. In general, attachment occurs when the smartphone registers with an authentication, authorization, and account (AAA) server. Such AAA registration and non-3GPP domain attachment occur outside the auspices of existing MME/SGSN registration and 3GPP domain attachment topologies, which means that terminating a phone call to a smartphone attached to a non-3GPP domain is at best difficult to accomplish. As such, seamless integration between mobile communication networks using a 4G protocol or the 2G/3G protocol and WLANs connected to the Internet is difficult to achieve in practice.

[0011] FIG. 1 shows an example wireless mobile communication network and WLAN architecture 100 in which wireless devices can receive phone calls when attached to a 3GPP domain, such as a 4G-type or a 2G/3G-type domain, or when attached to a non-3GPP domain, such as a WLAN-type domain. The architecture 100 includes a home subscriber server (HSS) 102, an MME 104, an SGSN 106, and an AAA server 108. The architecture 100 further includes 4G LTE wireless communication infrastructure 1 10, 2G/3G wireless communication infrastructure 1 12, and WLAN infrastructure 1 14. The architecture 100 includes user equipments (UEs) 1 16 and a service centralization and continuity

application server (SCC-AS) 1 18. The communication depicted in FIG. 1 among the HSS 102, the MME 104, the SGSN 106, the AAA server 108, the

infrastructures 1 10, 1 12, and 1 14, and the SCC-AS 1 18 is specifically signaling communication for maintaining and determining registration of the UEs 1 16 with the MME 104, the SGSN 106, and the AAA server 108 as managed by the HSS 102.

[0012] The HSS 102 communicates over wired communication lines with the MME 104, the SGSN 106, the AAA server 108, and the SCC-AS 1 18. The MME 104 communicates over a wired communication line with the LTE wireless communication infrastructure 1 10 that supports a 4G-type 3GPP access domain, and the SGSN 106 communicates over a wired communication line with the 2G/3G wireless communication infrastructure 1 12 that supports a 2G/3G-type 3GPP access domain. The AAA server 108 also communicates over a wired communication line with the WLAN infrastructure 1 14 that supports a WLAN-type non-3GPP access domain, such as a VoWLAN-type non-3GPP access domain in the case of voice communication like phone calls. The UEs 1 16 communicate wireless with the infrastructures 1 10, 1 12, and 1 14.

[0013] The HSS 102 is a type of server, and maintains registrations of the UEs 1 16 with the MME 104, the SGSN 106, and the AAA server 108. The MME 104 is a type of network component or cellular communication network device that is compatible with the just the LTE protocol, and the SGSN 106 is a type of network component or cellular communication network device that is compatible with just the 2G/3G protocol. The AAA server 108 is another type of server, which performs authentication, authorization, and accounting functionality for WLAN communication, including VoWLAN communication) in relation to the UEs 1 16. That is, the AAA server 108 authenticates a UE 1 16 to verify that the UE 1 16 is that which it identifies itself as, authorizes the UE 1 16 so that it

communicate over WLAN, such as participating in VoWLAN voice

communication, and performs accounting as to the usage of the WLAN infrastructure 1 14 by the UE 1 16.

[0014] The wireless communication infrastructure 1 10 includes the radio transmission towers and other components with which the UEs 1 16 directly communicate in a wireless manner using the LTE protocol, including VoLTE for voice communication. The wireless communication infrastructure 1 12 includes the radio transmission towers and other components with which the UEs 1 16 directly communicate in a wireless manner using the 2G/3G protocol, including voice communication in a circuit-switching manner. The WLAN infrastructure 1 14 includes the access points, routers, and other components with which the UEs 1 16 directly communicate in a wireless manner using an IP protocol, including VoWLAN such as VoWiFi for voice communication. The WLAN infrastructure 1 14 may include the Internet, or connections thereto. The UEs 1 16 are wireless devices, such as wireless mobile devices like smartphones.

[0015] The HSS 102 maintains LTE registration of the UEs 1 16 with the MME 104, 2G/3G registration of the UEs 1 16 with the SGSN 106, and WLAN registration of the UEs 1 16 with the AAA server 108. Registration of a UE with a component like the MME 104, the SGSN 106, or the AAA server 108 means that the UE 1 16 has moved into a physical location serviced by the component in question, and as such registers with the component to receive wireless communication services in that area. A UE 1 16 can be concurrently registered with more than one of the MME 104, the SGSN 106, and the AAA server 108.

[0016] When a phone call (i.e., a voice communication) is initiated to a UE 1 16, the SCC-AS 1 18 has to determine the current registration of the UE 1 16 so that the SCC-AS 1 18 can terminate the phone call to the UE 1 16. Registration of the UE 1 16 with the AAA server 108 means that the UE 1 16 is attached to a non- 3GPP domain, and is able to receive voice communication over VoWLAN.

Registration of the UE 1 16 with the MME 104 means that the UE 1 16 is attached to a 4G-type 3GPP domain, and can receive voice communication over VoLTE if supported. Registration of the UE 1 16 with the SGSN 106 means that the UE 1 16 is attached to a 2G/3G-type 3GPP domain. Priority among VoWLAN, VoLTE, and circuit switching may be specified by the provider of the architecture 100 or by the user of the UE 1 16. For example, one prioritization may favor VoWLAN over VoLTE, and both VoWLAN and VoLTE over circuit switching.

[0017] FIG. 2 shows an example method 200 for providing seamless integration among the LTE infrastructure 1 10, the 2G/3G infrastructure 1 12, and the WLAN infrastructure 1 14 when terminating a voice communication to a UE 1 16. The HSS 102 performs the method 200. In one implementation, VoWLAN is prioritized over VoLTE, which is prioritized over circuit switching, when terminating a phone call to the UE 1 16. Furthermore, in one implementation, it is assumed that registration of the UE 1 16 with the MME 104 means that the UE 1 16 can perform voice communication using VoLTE.

[0018] The HSS 102 receives a request from the SCC-AS 1 18 pertaining to the UE 1 16 (202). The SCC-AS 1 18 generates the request to determine what access domain to which the UE 1 16 is currently attached, so that the SCC-AS 1 18 can appropriately route an incoming phone call to the UE 1 16. This request can be a terminating access domain selection (T-ADS)-related request.

[0019] In response to receiving the request, the HSS 102 determines whether the UE 1 16 is currently registered with the AAA server 108 (204). In one implementation, the HSS 102 does not have this information stored, and therefore queries the AAA server 108 (206). In response, the HSS 102 receives from the AAA server 108 information regarding the registration of the UE 1 16 with the AAA server 108 if the UE 1 16 is registered with the AAA server 108, or an indication that the UE 1 16 is not registered with the AAA server 108 (208).

[0020] In another implementation, the HSS 102 determines whether the AAA server 108 previously provided the information (210). In general, when the UE 1 16 registers with the AAA server 108 for attachment to the VoWLAN-type non-3GPP access domain, the AAA server 108 provides this registration information to the HSS 102, which the HSS 102 then stores. However, some implementations of the HSS 102 may perform parts 206 and 208 in lieu of part 210, just in case the information previously provided has changed.

[0021] If the UE 1 16 is registered with the AAA server 108, then the HSS 102 concludes that the UE 1 16 is currently attached to the VoWLAN-type non- 3GPP access domain (214). In this respect, it is noted that the HSS 102 may not have any direct knowledge that the UE 1 16 is indeed attached to this access domain. Rather, the HSS 102 presumes that the UE 1 16 is currently attached to the VoWLAN-type non-3GPP access domain if the UE 1 16 is currently registered with the AAA server 108. This presumption is innovative, because it permits the HSS 102 to leverage existing information regarding registration of the UE 1 16 with the AAA server 108.

[0022] The HSS 102 returns a response to the SCC-AS 1 18 providing the information regarding the registration of the UE 1 16 with the AAA server 108 (216). This information thus permits the SCC-AS 1 18 to terminate an incoming voice communication to the currently attached VoWLAN-type non-3GPP access domain of the UE 1 16. The response can be a T-ADS-related response, and can be considered as providing infornnation regarding the VoWLAN-related access domain of the UE 1 16 as its current access domain. The information may include, for instance, the type of network to which the UE 1 16 is currently attached, on which basis the SCC-AS 1 18 can determine whether the UE 1 16 could receive a VoIP phone call with sufficient quality and then correspondingly terminate the incoming phone call at the UE 1 16.

[0023] If the UE 1 16 is not registered with the AAA server 108, however, then the HSS 102 determines whether the UE 1 16 is registered with the MME 104 or the SGSN 106 (218). In one implementation, the HSS 102 maintains registration of the UE 1 16 with the MME 104 and the SGSN 106, and can determine this information directly, whereas in another information the HSS 102 may query the MME 104 and the SGSN 106 in a similar manner by which it queried the AAA server 108 in part 206. If the UE 1 16 is registered with the MME 104 (220), regardless of whether the UE 1 16 is registered with the SGSN 106 (224), then in one implementation the HSS 102 responsively returns a response to the SCC-AS 1 18 providing the information regarding this registration. By comparison, if the UE 1 16 is not registered with the MME 104 (220) but is registered with the SGSN 106 in one implementation (224), then the HSS 102 responsively returns a response to the SCC-AS 1 18 providing the information regarding this registration.

[0024] The information regarding the registration with the MME 104 returned in part 222 can include the identification of the LTE cell within which the UE 1 16 is currently located. Similarly, the information regarding the registration with the SGSN 106 returned in part 226 can include the identification of the 2G/3G cell within which the UE 1 16 is currently located. Both types of registration indicate that the UE 1 16 is currently attached to a 3GPP access domain. In the former case, the 3GPP access domain is a 4G-type (such as LTE-type) 3GPP access domain, whereas in the latter case, the 3GPP access domain is a 2G/3G-type access domain. The response that the HSS 102 returns in part 222 or 226 can be a T-ADS-related response.

[0025] If the UE 1 16 is not currently registered with the AAA server 108 (212), is not currently registered with the MME 104 (220), and is not currently registered with the SGSN 108 (224), then the HSS 102 responsively returns a response to the SCC-AS 1 18 indicating that the UE 1 16 is not currently registered (228). This may also be a T-ADS-related response. The UE 1 16 may not be currently registered because it is powered off, or has been placed in a mode in which its radios for communicating with the infrastructures 1 10, 1 12, and 1 14 have been turned off. The UE 1 16 further may not be currently registered because even though its radios are on, the UE 1 16 is located in a physical location that is out of range of the LTE infrastructure 1 10, the 2G/3G

infrastructure 1 12, and the WLAN infrastructure 1 14.

[0026] The method 200 thus provides seamless integration between a mobile communication network - i.e., the LTE infrastructure 1 10 and the 2G/3G infrastructure 1 12 - and the WLAN infrastructure 1 14. Stated another way, the method 200 provides seamless integration with a VoWLAN-type non-3GPP access domain and 3GPP access domains like 4G-type (such as LTE-type) and 2G/3G-type 3GPP access domains. Regardless of whether a UE 1 16 is specifically registered with the MME 104, the SGSN 106, or the AAA server 108, and thus regardless of whether the UE 1 16 is specifically attached to a 3GPP access domain or a non-3GPP access domain, the UE 1 16 receives incoming voice communication such as phone calls.

[0027] It is noted, too, that the method 200 advantageously reduces or eliminates needless network traffic between the HSS 102 and the MME 104 and the SGSN 106. Specifically, if the UE 1 16 is registered with the AAA server 106, then the HSS 102 can automatically conclude that the UE 1 16 is currently attached to the VoWLAN-type non-3GPP access domain, and provide this information to the SCC-AS 1 18 for terminating the incoming phone call. That is, the HSS 102 in this implementation does not determine whether the UE 1 16 is registered with the MME 104 or the SGSN 106 (i.e., with a cellular

communication network device). As such, network traffic between the HSS 102 and the MME 104 and the SGSN 106 is reduced.

[0028] FIG. 3 shows an example server 300, which may implement the HSS 102. The server 300 includes networking hardware 302, an access domain determiner 304, and a memory 306. The server 300 can and typically does include other components, in addition to those depicted in FIG. 3. The

networking hardware 302 permits the server 300 to communicate with networking components, such as the MME 104 and the SGSN 106, and servers, such as the AAA server 108 and the SCC-AS 1 18, in a wired manner. [0029] The access domain determiner 304 performs the method 200 that has been described. The determiner 304 may be implemented in hardware or in a combination of hardware and software. In the former implementation, the determiner 340 may be an application-specific integrated circuit (ASIC) or a field- programmable gate array (FPGA), for instance, appropriately programmed to perform the method 200. In the latter implementation, the determine 340 may include a non-transitory computer-readable data storage medium storing computer-executable code that when executed by a hardware processor performs the method 200.

[0030] The memory 306 is a hardware memory, and may be volatile memory or non-volatile. The memory 306 stores a flag 308. The flag 308 is set to indicate that on the mobile communication network on which wireless devices like the UEs 1 16 communicate, VoWLAN is enabled. As such, the access domain determiner 304 performs the method 200 when the flag 308 is set. That is, the determiner 340 determines whether wireless devices are registered with an authorization server when the flag is set. The flag is a network-wide flag.

[0031] The memory 306 can also stores VoWLAN information 310. The information 310 is with respect to the current attachment of wireless devices, such as the UEs 1 16, that the authorization server provided when the wireless devices were attached to a VoWLAN-related access domain. As has been described above, the AAA server 108, for instance, sends this information to the HSS 102 when a UE 1 16 registers with the server 108. This information may include radio access technology (RAT)-type infornnation, which specifies that the radio access in question is WLAN, for example, as opposed to 4G or 2G/3G.