HK1175921B - Interworking of networks with single radio handover - Google Patents

Description

Interworking of networks with single radio handover

Technical Field

The present disclosure relates generally to the field of wireless communications, and more particularly to interworking of networks using radio systems with multi-networking capability across heterogeneous networks.

Background

As wireless communications become increasingly popular in offices, homes, and schools, different wireless technologies and applications may be available to meet the demand for computing and communications at any time and/or anywhere. For example, multiple wireless communication networks may coexist to provide a wireless environment with more computing and/or communication capabilities, greater mobility, and/or ultimately seamless roaming.

In particular, Wireless Personal Area Networks (WPANs) may provide fast short-range connectivity within a relatively small space, such as an office workspace or a room within a home. Wireless Local Area Networks (WLANs) may provide a wider range than WPANs within office buildings, homes, schools, and the like. Wireless Metropolitan Area Networks (WMANs) may cover greater distances than WLANs by interconnecting, for example, buildings over a wider geographic area. Wireless Wide Area Networks (WWANs) may provide even wider range as such networks are widely deployed in cellular infrastructure. While each of the above wireless communication networks may support different uses, the ability to seamlessly interwork across two or more of these networks would be useful.

Drawings

The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

fig. 1 illustrates a wireless network according to some embodiments;

fig. 2 shows a block diagram of a Station (STA) according to various embodiments;

fig. 3 is a block diagram of an architecture for interworking of networks, in accordance with some embodiments;

FIG. 4 is another block diagram illustrating interworking function elements according to some embodiments;

FIG. 5 illustrates network entry using an interworking function element, in accordance with some embodiments;

fig. 6 illustrates a single radio handover without a pre-existing context (context), in accordance with some embodiments;

fig. 7 illustrates a single radio handover in idle mode, in accordance with some embodiments;

figure 8 illustrates a single radio handover with pre-existing context, in accordance with some embodiments;

fig. 9 illustrates a single radio handover with access control in an interworking function, in accordance with some embodiments; and

fig. 10 is a flow diagram of a method for interworking of networks, according to some embodiments.

It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding or analogous elements.

Detailed Description

In the following detailed description, numerous specific details for providing interworking of networks using single radio handover are set forth in order to provide a thorough understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.

It would be an advancement in the art to provide systems and methods for interworking of networks using multi-radio systems or systems with a single radio that lack the ability to operate two separate networks simultaneously or nearly simultaneously by sharing the radio. Interworking of networks in this manner may allow for authenticated, roaming, integrated billing, and optimized handoff use of single credentials for systems such as platforms, Stations (STAs), mobile STAs, advanced mobile STAs, and subscriber STAs.

For example, a first network (e.g., a wireless fidelity (WiFi) network) may be used to access a second network (e.g., a Worldwide Interoperability for Microwave Access (WiMAX) network) using a single radio handover. In this embodiment, the WiFi network is a WLAN and the WiMAX network is a WWAN. WiFi is widely used in many public, business, and residential environments. Due to its unlicensed nature, WiFi cannot cover very large areas, while WiMAX is a cellular technology designed to cover large outdoor environments. However, WiMAX does not provide adequate coverage in an indoor environment. The combination of one or more MLANs and one or more WiMAX networks can potentially provide ubiquitous indoor and outdoor coverage. A system and method for interworking between networks that provides for transfer from one network to another in a transparent manner without causing meaningful or perceptible interruption to one or more active sessions of a user would be useful.

Turning now to the figures, fig. 1 illustrates a wireless communication system 100 in accordance with some embodiments of the present invention. The wireless communication system 100 may include one or more wireless networks, shown generally as 110, 120, and 130. In particular, wireless communication system 100 may include a Wireless Wide Area Network (WWAN) 110, a Wireless Local Area Network (WLAN) 120, and a Wireless Personal Area Network (WPAN) 130. Although fig. 1 depicts three wireless networks, the wireless communication network 100 may include additional or fewer wireless communication networks. For example, the wireless communication system 100 may include one or more Wireless Personal Area Networks (WPANs), additional WLANs, WWANs, and/or WMANs. The methods and apparatus described herein are not limited in this respect.

The wireless communication system 100 also includes one or more Stations (STAs), including platforms, clients, subscriber stations, mobile stations, and advanced mobile stations, generally shown as a multi-radio station 135 capable of accessing multiple wireless networks using multiple radios, and a single radio station 140 that may lack the ability to operate two different radios at the same time or nearly the same time due to the STA being configured with a single Radio Frequency (RF) module or communication device. For example, STAs 135 and 140 may comprise wireless electronic devices such as desktop computers, laptop computers, handheld computers, tablet computers, cellular telephones, smart phones, pagers, audio and/or video players (e.g., MP3 player or DVD player), gaming devices, video cameras, digital cameras, navigation devices (e.g., GPS device), wireless peripherals (e.g., printer, scanner, headset, keyboard, mouse, etc.), medical devices (e.g., heart rate monitor, blood pressure monitor, etc.), and/or other suitable fixed, portable, or mobile electronic devices. Although fig. 1 depicts seven STAs, the wireless communication system 100 may include more or fewer STAs 135 and 140.

STAs 135 and 140 may use a variety of modulation techniques such as spread spectrum modulation (e.g., direct sequence code division multiple access (DS-CDMA) and/or frequency hopping code division multiple access (FH-CDMA)), Time Division Multiplexing (TDM) modulation, Frequency Division Multiplexing (FDM) modulation, Orthogonal Frequency Division Multiplexing (OFDM) modulation, Orthogonal Frequency Division Multiple Access (OFDMA), multi-carrier modulation (MDM), and/or other suitable modulation techniques to communicate via a wireless link.

In one embodiment, the STAs 135 and 140 may implement the WLAN 120 using Direct Sequence Spread Spectrum (DSSS) modulation and/or Frequency Hopping Spread Spectrum (FHSS) modulation (e.g., the 802.11 family of standards developed by the Institute of Electrical and Electronics Engineers (IEEE) and/or variations and evolutions of these standards). For example, the STAs 135 and 140 may communicate with other STAs 135 and 140 or the access point 125 in the WLAN 120 via wireless links. The AP 125 may be operably coupled to a router (not shown). Alternatively, the AP 125 and the router may be integrated into a single device (e.g., a wireless router).

STAs (e.g., multi-radio station 1125 and single-radio station 140) may use OFDM or OFDMA modulation to transmit large amounts of digital data by splitting a radio frequency signal into multiple small sub-signals, which in turn are transmitted simultaneously at different frequencies. In particular, STAs 135 and 140 may implement WWAN 110 using OFDMA modulation. For example, the STAs may operate in accordance with 802.16 family standards developed by IEEE to provide fixed, portable, and/or mobile Broadband Wireless Access (BWA) networks (e.g., IEEE standard 802.16 published in 2004) to communicate with the base or advanced base station 105 via wireless link(s).

Although some of the above examples are described above with respect to specific standards developed by IEEE, the methods and apparatus disclosed herein are readily applicable to many specifications and/or standards developed by other special interest groups and/or standard development organizations (e.g., wireless fidelity (WiFi) alliance, Worldwide Interoperability for Microwave Access (WiMAX) forum, infrared data association (IrDA), third generation partnership project (3 GPP), etc.). In some embodiments, access point 125 and/or base station 105 may communicate in accordance with a particular communication standard, such as an Institute of Electrical and Electronics Engineers (IEEE) standard, including IEEE 802.11 (a), 802.11 (b), 802.11 (g), 802.11 (h), and/or 802.11 (n) standards and/or specifications set forth for WLANs, although the scope of the invention is not limited in this respect as they may also be suitable for transmitting and/or receiving communications in accordance with other techniques and standards. In some embodiments, access point 125 and/or base station 105 may communicate in accordance with the IEEE 802.16-2004, IEEE 802.16 (e), and IEEE 802.16 (m) standards, including variations and evolutions thereof, although the scope of the invention is not limited in this respect as they may also be suitable to transmit and/or receive communications in accordance with other techniques and standards.

For more Information on the IEEE 802.11 and IEEE 802.16 Standards, reference is made to "IEEE Standards for Information Technology- -Telecommunications and Information Exchange between Systems" - -Local Area Networks-Specific Requirements-Part 11 "Wireless LAN Medium Access Control (MAC) and Physical Layer 880 (PHY), ISO/IEC 2-11: 1999" and Metapolar Area Networks-Specific Requirements-Part 16: "Air Interface for Fixed Broadband Wireless Access (System 2005 month 5) and related modifications/versions.

WWAN 110 and WLAN 120 may be operatively coupled to a public or private network 145 such as the internet, a telephone network (e.g., the Public Switched Telephone Network (PSTN)), a Local Area Network (LAN), a cable network, and/or another wireless network via a connection to an ethernet, a Digital Subscriber Line (DSL), a telephone line, a coaxial cable, and/or any wireless connection, among others. In one example, WLAN 120 may be operatively coupled to public or private network 145 via AP 125, and WWAN 110 may be operatively coupled to public or private network 145 via base station 105.

STAs 135 and 140 may operate in accordance with other wireless communication protocols to support WWAN 110. In particular, these wireless communication protocols may be based on analog, digital, and/or dual-mode communication system technologies (e.g., global system for mobile communications (GSM) technologies, Wideband Code Division Multiple Access (WCDMA) technologies, General Packet Radio Service (GPRS) technologies, Enhanced Data GSM Environment (EDGE) technologies, Long Term Evolution (LTE), Universal Mobile Telecommunications System (UMTS) technologies), standards based on these technologies, variations and evolutions of these standards, and/or other suitable wireless communication standards.

The wireless communication system 100 may also include other WPAN, WLAN, WWAN, and/or WMAN devices (not shown) such as network interface devices and peripherals (e.g., Network Interface Cards (NICs)), Access Points (APs), redistribution points, endpoints, gateways, bridges, hubs, and the like, to implement a cellular telephone system, a satellite system, a Personal Communication System (PCS), a two-way radio system, a one-way paging system, a two-way paging system, a Personal Computer (PC) system, a Personal Data Assistant (PDA) system, a Personal Computing Assistant (PCA) system, and/or any other suitable communication system. Although certain examples have been described above, the scope of coverage of this disclosure is not limited thereto.

Fig. 2 shows a block diagram of a single radio station 140 according to various embodiments of the present invention. The single radio station 140 may include one or more host processors or central processing unit(s) (CPUs) 202 (which may be collectively referred to herein as "processors 202" or more generally "processor 202") coupled to an interconnection network or bus 204. The processor 202 may be any type of processor such as a general purpose processor, a network processor (which may process data communicated over a computer network), or the like (including a Reduced Instruction Set Computer (RISC) processor or a Complex Instruction Set Computer (CISC)). Further, the processors 202 may have a single or multiple core design. Processors 202 with a multiple core design may integrate different types of processor cores on the same Integrated Circuit (IC) die. Also, the processors 202 with a multiple core design may be implemented as symmetric or asymmetric multiprocessors.

The processor 202 may include one or more caches 203, which may be private and/or shared in various embodiments. Generally, cache 203 stores data corresponding to raw data stored elsewhere or computed earlier. To reduce memory access latency, once data is stored in cache 203, future use may be accomplished by accessing a cached copy rather than refetching or recalculating the original data. The cache 203 may be any type of cache (e.g., a level 1 (L1) cache, a level 2 (L2) cache, a level 3 (L-3) cache, a mid-level cache, a Last Level Cache (LLC), etc.) to store electronic data (e.g., including instructions) utilized by one or more components of the multi-communication platform 200.

A chipset 206 may additionally be coupled to the interconnection network 204. The chipset 206 may include a Memory Control Hub (MCH) 208. The MCH 208 may include a memory controller 210 coupled to a memory 212. The memory 212 may store data, including for example sequences of instructions that are executed by the processor 202 or any other device in communication with the components of the single radio station 140. In various embodiments, the memory 212 may include one or more volatile storage or memory devices, such as Random Access Memory (RAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Static RAM (SRAM), and so forth. Non-volatile memory (e.g., a hard disk) may also be utilized. Additional devices may be coupled to the interconnection network 204, such as multiple processors and/or multiple system memories.

The MCH 208 may also include a graphics interface 214 coupled to a display 216, e.g., via a graphics accelerator. In various embodiments, a display device 216 (which may include, for example, a flat panel display or cathode ray tube) may be coupled to the graphics interface 214 through, for example, a signal converter that converts a digital representation of an image stored in a storage device (e.g., video memory or system memory) into display signals that are interpreted and displayed by the display. The display signals generated by the display device 216 may pass through various control devices before being interpreted by the display device 216 and subsequently displayed on the display device 216.

As shown in FIG. 2, a hub interface 218 may couple the MCH 208 to an input/output control hub (ICH) 220. The ICH 220 may provide an interface to input/output (I/O) devices coupled to the single radio station 140. The ICH 220 may be coupled to a bus 222 through a peripheral bridge or host controller 224 (e.g., a Peripheral Component Interconnect (PCI) bridge, a Universal Serial Bus (USB) controller, etc.). The controller 224 may provide a data path between the processor 202 and peripheral devices. Other types of topologies may be utilized. Further, multiple buses may be coupled to the ICH 220, e.g., through multiple bridges or controllers. For example, bus 222 may conform to the universal serial bus specification at 23/9/1998, the universal serial bus specification at 27/4/2000, revision 2.0 (including subsequent modifications to either revision). Alternatively, the bus 222 may comprise other types and configurations of bus systems. Moreover, other peripherals coupled to the ICH 220 may include, in various embodiments, Integrated Drive Electronics (IDE) or Small Computer System Interface (SCSI) hard drive(s), USB port(s), a keyboard, a mouse, parallel port(s), serial port(s), floppy disk drive(s), digital output support (e.g., Digital Video Interface (DVI)), and so forth.

The bus 222 may be coupled to a video device 226, one or more rotating or solid state disk drives 228, and a communication device 230, which may be a Network Interface Card (NIC) or tuner card in various embodiments. Other devices may be coupled to the bus 222. Also, various components (e.g., the communication device 230) may be coupled to the MCH 208 in various embodiments. In addition, the processor 202 and the MCH 208 may be combined to form a single chip.

In addition, the single radio station 140 may include volatile and/or non-volatile memory or storage. For example, the non-volatile memory may include one or more of the following: read-only memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Electrically EPROM (EEPROM), a disk drive or solid state drive (e.g., 228), a floppy disk, a compact disk ROM (CD-ROM), a Digital Versatile Disk (DVD), flash memory, a magneto-optical disk, or other types of nonvolatile machine-readable media that are capable of storing electronic data including instructions.

Memory 212 may include one or more of the following in various embodiments: an operating system (O/S) 232, applications 234, device drivers 236, buffers 238, function drivers 240, and/or protocol drivers 242. Programs and/or data stored in the memory 212 may be swapped into the solid state drive 228 as part of memory management operations. Processor(s) 302 executes various commands and processes one or more packets 246 with one or more computing devices coupled to WLAN 120 or WWAN 110. In various embodiments, a packet may be a sequence of one or more symbols and/or values that may be encoded by one or more electrical signals transmitted from at least one transmitter to at least one receiver (e.g., over a network such as network 102). For example, each packet may have a header that includes information that may be utilized in the routing and/or processing of the packet, which may include continuity counters, synchronization bytes, source addresses, destination addresses, packet types, and so forth. Each packet may also have a payload that includes the original data or content that the packet is communicating between the various stations.

In various embodiments, the applications 234 may utilize the O/S232 to communicate with various components of the single radio station 140, such as through a device driver 236 and/or a function driver 240. For example, the device driver 236 and the function driver 240 may be used for different categories, e.g., the device driver 236 may manage general device class attributes, while the function driver 240 may manage device specific attributes (e.g., USB specific commands). In various embodiments, the device driver 236 may allocate one or more buffers to store packet data.

As shown in fig. 2, the communication device 230 includes a first network protocol layer 250 and a second network protocol layer 252 that implement a physical communication layer to transmit and receive network packets to and from the base station 105, the access point 105, and/or other STAs (e.g., multi-radio station 135 and single-radio station 140). The communication device 230 may also include a Direct Memory Access (DMA) engine 252 that may write packet data to the buffer 238 to transmit and/or receive data. Additionally, the communication device 230 may include a controller 254, which may include logic (e.g., such as a programmable processor) to perform operations related to the communication device. In various embodiments, controller 254 may be a MAC (media access control) component. The communication device 230 may also include a memory 256 (e.g., any type of volatile/non-volatile memory (e.g., including one or more caches and/or other memory types discussed with reference to memory 212)) and an antenna 262. Antenna 262 may represent a single structure or an array of multiple structures for the reception and/or transmission of signals.

In various embodiments, communication device 230 may include a firmware storage 260 that stores firmware (or software) that may be utilized in the management of various functions performed by components of communication device 230. Storage device 260 may be any type of storage device, such as a non-volatile storage device. For example, storage device 260 may include one or more of the following: ROM, PROM, EPROM, EEPROM, disk drive, floppy disk, CD-ROM, DVD, flash memory, magneto-optical disk, or other type of non-volatile machine-readable medium capable of storing electronic data including instructions.

In various embodiments, bus 222 may comprise a USB bus. Isochronous mode is one of the four data stream types for USB devices (others are control, interrupt and bulk). Isochronous mode is typically used for streaming multimedia data types such as video or audio sources. In isochronous mode, the device may reserve bandwidth on the bus, making isochronous mode desirable for multimedia applications. The single-radio STA 140 may be configured to communicate over two networks (e.g., WWAN 110 and WLAN 120) using the same communication device 230, although not simultaneously. This may make interworking between networks difficult because network entry may take a relatively long period of time, resulting in service interruption or loss of service.

Fig. 3 is a block diagram of a system for interworking of networks, in accordance with some embodiments. The single radio station 140 establishes access to the WLAN 120 through the interworking Access Point (AP) 125 using a first Service Set Identifier (SSID) 306. In alternative embodiments, the interworking AP 310 is a carrier-like WiFi access point that separates STAs with network interworking capabilities from other STAs, and/or the first SSID 306 is a broadcast SSID (BSSID). The single radio station 140 communicates with the interworking AP 310 through user traffic using a first SSID 306, which is mapped to a separate Virtual Local Area Network (VLAN). Devices provisioned to interwork between networks (e.g., the single radio station 140) may search for an interworking SSID in the WLAN 120. The interworking AP 310 may communicate with multiple STAs (which include a single radio station 140 with or without network interworking capabilities). In addition, the interworking AP may also communicate with one or more other STAs (including the multi-radio STA 135) using the second SSID 307.

A device provisioned to interwork between a first network (e.g., WLAN 120) and a second network (e.g., WMAN 110) may search for an interworking SSID in the first network. The interworking AP 310 may use a link (e.g., a networking standard) to allow multiple bridging networks to transparently share a common physical network link. One such example that may be used is the IEEE 802.1Q protocol, such as tunneling VLAN traffic to a tunnel endpoint (e.g., an ethernet switch or router 315). The use of the 802.1Q protocol may allow for the separation of conventional internet and interworking traffic and also allow for the same Internet Protocol (IP) address assignment to various devices (e.g., single radio STA 140 and multi-radio STA 135) on the same interworking AP 310. Switch/router 315 is linked to network infrastructure 320 to provide access to the internet and internet protocol services 350.

Switch/router 315 is also coupled to a WiFi Interworking Function (WIF) 325 element. The WIF 325 is a network element located between the first network and the second network and interfaces the two networks (e.g., the WiFi network of the WLAN 120 and the WiMAX network of the WMAN 110). The WIF 325 serves as a data path and control path anchor on behalf of an interworking STA (e.g., single radio STA 140 or multi-radio STA 135). The WIF 325 is further described below with reference to fig. 4. Referring to fig. 3, WIF 325 interfaces with several elements of WWAN 110, including interfacing with an access service network gateway (ASN-GW) 335 through a first control line 326, interfacing with AAA 340 elements through a second control line 327, and interfacing with a Home Agent (HA) 345 through a first link 328, where solid lines indicate user traffic and dashed lines indicate control traffic. HA 345 of WMAN 110 is linked to internet/IP services 350 elements. WMAN 110 also includes other elements, such as one or more base stations 330 linked to ASN-GW 335.

In one embodiment, a STA (e.g., multi-radio station 135 or single-radio station 140) receives a signal from an AP 125 in a first network (e.g., WLAN 120). The STA studies the signal to identify the SSID and uses the SSID to determine whether the AP 125 supports interworking of networks to access a second network (e.g., WMAN 110) using the first network. The STA then associates with the first network to access the second network using the WIF 325.

Figure 4 is another block diagram illustrating a WIF 325 element including AN AAA proxy 405 for tunnel authentication, authorization, and accounting exchanges between a WiFi Access Network (AN) 430 and AN AAA 340 element (e.g., AAA server), in accordance with some embodiments. In fig. 4, solid lines indicate user traffic and dotted lines indicate control traffic.

The WIF 325 also includes a single (singling) forwarding function 410 to enable single radio handover from the WLAN 120 (which may be a WiFi network) to the WMAN 110 (which may be a WiMAX network). The WIF 325 also includes a DHCP proxy 415 to respond to client request(s) for IP address (es) and trigger a Proxy Mobile IP (PMIP) procedure towards the HA 345 through the PMIP client 420. The WIF 325 also includes a data path function or mobile IP Foreign Agent (FA) to facilitate data path tunneling from the WLAN Access Network (AN) 430 to the HA 345.

To support mobility, various scenarios need to be considered when determining a method for interworking of networks, as described below in table 1:

	mobility patterns	Pre-existing context
			Case 1	Free up	Without context
Case 2	Free up	Having a context of presence
			Case 3	Movement of	Without context
Case 4	Movement of	Having a context of presence

Table 1. handover situation.

In one embodiment, a method for interworking of networks includes receiving a signal from a first network. The signal may be received by a STA (e.g., single radio station 140 or multi-radio station 135) from WLAN 120, where WLAN 120 is a WiFi network. Signals are studied in the STA to determine whether an Access Point (AP) in the first network deploys a virtual AP using the BSSID. The BSSID is used to determine whether the AP supports interworking of networks to access a second network using a first network. The STA associates with the first network to access the second network using a WiFi Interworking Function (WIF) 325 element.

Figure 5 illustrates a network entry procedure for WiFi and WiMAX networks using WIF 325 elements, according to some embodiments. Several elements are used in the process including a Mobile Station (MS) 505, which Mobile Station (MS) 505 may be the single radio station 140 or the multi-radio station 135 of fig. 1. WiFi AN 510, WIF 325, HA 345 and AAA 340 are also used in this process.

By capturing a WiFi signal by MS 505 and performing WiFi network discovery and selection, access to a first network is established through association 530 of MS 505 to WiFi AN 510. MS 505 authenticates to the Core Service Network (CSN) of the WiMAX network by sending messages through WiFi AN 510 and reaching WIF 325, where AAA proxy 405 facilitates authentication of MS 505 to AAA 340 server. A DHCP discover message 540 is sent from MS 505 to WIF 325 for discovering the DHCP server. The DHCP proxy 415 in the WIF 325 may be used for discovery purposes. A Mobile IP (MIP) registration request 545 may be sent to the HA 345 and a MIP registration response is sent to the WIF 325 to form a MIP tunnel. The MS 505 receives a DHCP offer 555 message from the DHCP proxy 415 in the WIF 325. The MS 505 responds to the DHCP offer 555 by sending a DHCP request 560 message to the DHCP proxy 415 in the WIF 325. DHCP proxy 415 in WIF 325 sends a DHCP acknowledge 565 message to MS 505 to provide data 570 to be sent from MS 505 and from the WiFi network to the WiMAX network.

A method of network entry by a STA includes receiving a first signal from a first network using the STA, the STA configured to communicate over the first network and a second network. The first network is a wireless fidelity (WiFi) network and the second network is a Worldwide Interoperability for Microwave Access (WiMAX) network. An association is established with the first network and the STA is authenticated in the second network by sending EAP messages to the WIF via the AP. A DHCP discover message is transmitted to discover the DHCP server. The DHCP offer message is received by the STA and, in response, a DHCP request message is sent. An acknowledgement is received from the WIF 325 and data is transmitted by the STA over the second network using the first network.

Fig. 6 illustrates a single radio handover without a pre-existing context, in accordance with some embodiments. Several elements are used in the process including a Mobile Station (MS) 505, which Mobile Station (MS) 505 may be the single radio station 140 or the multi-radio station 135 of fig. 1. Also used in this process are a WiFi AN 510, a HA 345, AN AAA 340, a Separate Forwarding Function (SFF) 605 to enable single radio handover from a WiFi network to a WiMAX network, a target Base Station (BS) in a WiMAX network, and AN access service network gateway (ASN-GW) 335. SFF 605 may also be referred to as WIF 325.

MS 505 in fig. 6 enters WiFi network 615, using, as an example, the method shown in fig. 5 and described above. The MS 505 detects availability of WiMAX network, availability of interworking capability, discovers SFF 605, and decides to create WiMAX context 620. Exchanging a series of messages or calls comprising one or more of: ranging (RNG) Request (REQ)/Response (RSP) 621 between MS 505 and SFF 605, Station Basic Capability (SBC) REQ/RSP 622 exchange, pre-attach 623 exchange, secret key management (PKM)/EAP exchange 624, EAP authentication exchange 625, EAP authentication exchange 626, secure exchange (SA) Traffic Encryption Key (TEK) handshake 627, Registration (REG) REQ/RSP 628, MS attach REQ/RSP 629, Dynamic Service Assignment (DSA) REQ/RSP 630, and data path registration 631 exchange.

MS 505 decides to use a single radio handover using a tunnel formed to SFF 605 in the WiMAX network to switch to the WiMAX network in element 640. Performing a series of exchanges or calls comprising one or more of: MOB Mobile station Handover (MOB _ MSHO) -Req 641, Handover (HO) request 642, Req/Rsp 643, MOB-MSHO-Rsp 644, HO-Rsp 645, HO-Ack 646, HO-Ack 647, MOB _ HO-Ind 648, MOB _ Cnf 649, Cnf/Ack 650, and HO-Ack 651. Performing a single radio handover to WiMAX 660 using another series of messages or calls, the messages or calls including one or more of: network re-entry 661, data path registration 662, HO _ complete 663, HO _ complete 664, HO-Ack 665, HO-Ack 666, and data path de-registration 667 before data traffic 670 is established. The dashed box 680 indicates the procedure for a single radio handover to a WiMAX network with pre-existing context.

In a related embodiment, the STA performs the single radio handover using a method that includes connecting to a first network and detecting availability of a second network. The STA discovers an address of a Signal Forwarding Function (SFF) or WIF 325 of the second network and establishes a tunnel to the SFF of the second network. The STA then performs initial entry through the tunnel to the second network and performs handover to the base station 105 in the second network. The first network may be a wireless fidelity (WiFi) network and the second network may be a Worldwide Interoperability for Microwave Access (WiMAX) network.

Fig. 7 illustrates a single radio handover to a WiFi network in idle mode, in accordance with some embodiments. Several elements are used in the process including a Mobile Station (MS) 505, which Mobile Station (MS) 505 may be the single radio station 140 or the multi-radio station 135 of fig. 1. WiFi AN 510, WIF 325, target BS 610, ASN-GW 335, HA 345, and AAA 340 are also used in this process.

Data traffic 705 is exchanged between the MS 505, the target BS 610, and the HA 345, and a decision to handover to WiFi 710 is determined. With WiMAX idle 720, EAP authentication 722 messages or calls are exchanged between the MS 505, the WiFi AN 510, the WIF 325, and the AAA 340. A handoff of the IP virtual adapter to WiFi is performed in element 730. A DHCP discover message 732 is sent from MS 505 to WIF 325 for discovering the DHCP server. The DHCP proxy 415 in the WIF 325 may be used for discovery purposes. A Mobile IP (MIP) registration request 734 may be sent to the HA 345 and a MIP registration response 736 is sent to the WIF 325. The MS 505 receives the DHCP offer 738 message from the DHCP proxy 415 in the WIF 325. The MS 505 responds to the DHCP offer 555 by sending a DHCP request 740 message to the DHCP proxy 415 in the WIF 325. A DHCP acknowledge 742 message is sent by DHCP proxy 415 in WIF 325 to MS 505 to provide data 750 to be exchanged with MS 505.

Fig. 8 illustrates a single radio handover with a pre-existing context, in accordance with some embodiments. Data traffic 705 is exchanged between MS 505, WiFi AN 510, WIF 325, target BS 610, ASN-GW 335, and HA 345, and a decision to switch to WiFi 820 is determined. A handoff of the IP virtual adapter to WiFi is performed in element 830. DHCP discover message 832 is sent from MS 505 to WIF 325 for discovering the DHCP server. A Mobile IP (MIP) registration request 834 is sent to the HA 345 and a MIP registration response 836 is sent to the WIF 325. The MS 505 receives a DHCP offer 838 message from the DHCP proxy 415 in the WIF 325. The MS 505 responds to the DHCP offer 838 by sending a DHCP request 840 message to the DHCP proxy 415 in the WIF 325. A DHCP acknowledge 842 message is sent by DHCP proxy 415 in WIF 325 to MS 505 to provide data 850 to be exchanged with MS 505.

Fig. 9 illustrates a single radio handover with access control in an interworking function (WIF) in accordance with some embodiments. Data traffic 910 is exchanged between MS 505, target BS 610, ASN-GW 335, and HA 345, and a decision to switch to WiFi is determined in element 920. WIF/SFF discovery and authentication processes occur between MS 505, WiFi AN 510, and WIF 325 in element 930. A series of messages are exchanged between MS 505, WIF 325, target BS 610, and ASN-GW 335, including an uncontrolled Handover (HO) (RNG-REQ/IP) 932, context retrieval 934, handover to WiFi required 936, handover response to WiFi 938, handover complete 940, handover complete 942, handover ACK 944, and handover complete 946 messages.

A handoff of the IP virtual adapter to WiFi is performed in element 950. A DHCP discover message 952 is sent from MS 505 to WIF 325 for discovering the DHCP server. A Mobile IP (MIP) registration request 954 is sent to HA 345 and a MIP registration response 956 is sent to WIF 325. The DHCP offer 958 message is received by the MS 505 from the DHCP proxy 415 in the WIF 325. The MS 505 responds to the DHCP offer 838 by sending a DHCP request 960 message to the DHCP proxy 415 in the WIF 325. A DHCP acknowledge 962 message is sent by DHCP proxy 415 in WIF 325 to MS 505 to provide data 970 to be exchanged with MS 505.

Fig. 10 is a flow chart of a method for interworking of networks, including receiving a signal from a first network in element 1000. The signal may be received by the STA from the WLAN 120, where the WLAN 120 is a WiFi network. In element 1010, the signal is studied in the STA to identify a Service Set Identifier (SSID). In element 1020, the SSID is used to determine whether the AP supports interworking of networks to access a second network using a first network. In element 1030, the STA associates with the first network to access the second network using a WiFi Interworking Function (WIF) 325 element.

Embodiments may have been described herein with reference to data (e.g., instructions, functions, procedures, data structures, applications, configuration settings, etc.). For the purposes of this disclosure, the term "program" covers a wide range of software components and constructs, including applications, drivers, processes, routines, methods, modules, and subroutines. The term "program" may be used to refer to a complete compilation unit (i.e., a set of instructions that may be compiled independently), a collection of compilation units, or a portion of a compilation unit. Thus, the term "program" may be used to refer to any set of instructions that, when executed by the wireless communication system 100, performs a desired signal transmission. The programs in the wireless communication system 100 may be considered components of a software environment.

The operations discussed herein may be generally facilitated via execution of appropriate firmware or software embodied as code instructions on a tangible medium, where applicable. Thus, embodiments of the invention may include a set of instructions executed upon some form of processing core or otherwise implemented or realized upon or within a machine-readable medium. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable medium may include an article of manufacture such as a Read Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk storage medium, an optical storage medium, and a flash memory device, among others. Additionally, a machine-readable medium may include propagated signals such as electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.).

While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims (23)

1. A method for interworking of networks, comprising:

receiving a signal from an access point, AP, in a first network;

studying the signal to identify a service set identifier, SSID;

determining, using the SSID, whether the AP supports interworking of networks to access a second network using the first network; and

associating with the first network to access the second network using a wireless fidelity, WiFi, interworking function, WIF, element, wherein the WIF element includes a signal forwarding function, SFF, and a mobile Internet protocol, IP, foreign agent, FA, and wherein accessing the second network includes tunneling from the first network to the second network using the mobile IP FA.

2. The method of claim 1, wherein the AP is a carrier-class WiFi AP.

3. The method of claim 1, wherein the SSID is an interworking IWKSSID.

4. The method of claim 3, further comprising selecting the IWK SSID from a plurality of SSIDs, wherein each SSID is mapped into a separate Virtual Local Area Network (VLAN).

5. The method of claim 3, wherein the WIF element comprises: authentication, authorization and accounting AAA functions, or data path functions.

6. The method of claim 1, wherein the SSID is a broadcast SSID.

7. The method of claim 1, wherein the first network is a WiFi network and the second network is a worldwide interoperability for microwave access, WiMAX, network.

8. A method for network entry, comprising:

receiving a first signal from a first network using a Station (STA) configured to communicate over the first network and a second network;

establishing an association with the first network;

authenticating the STA in the second network by sending an Extensible Authentication Protocol (EAP) message to a WiFi Interworking Function (WIF) via an Access Point (AP), thereby enabling a single radio handover from the first network to the second network via a Signal Forwarding Function (SFF) in the WIF;

transmitting a Dynamic Host Configuration Protocol (DHCP) discovery message to discover a DHCP server;

receiving a DHCP offer message;

responding to the DHCP offer message with a DHCP request message;

receiving an acknowledgement from the WIF element; and

transmitting data over the second network using the first network via a mobile internet protocol, IP, foreign agent in the WIF.

9. The method of claim 8, wherein the first network is a WiFi network and the second network is a WiMAX network.

10. The method of claim 9, wherein the STA authenticates in the second network by sending extensible authentication protocol, EAP, messages to an authentication, authorization, and accounting, AAA, proxy in the WIF.

11. The method of claim 8, wherein the DHCP discover message is sent to the WIF.

12. The method of claim 8, wherein the DHCP offer message is received from the WIF.

13. The method of claim 12, wherein the DHCP request message is transmitted to the WIF.

14. The method of claim 8, wherein the AP is configured to provide multicast service set identifier BSSID support.

15. A single radio station, STA, comprising a first protocol layer for communicating over a first network and a second protocol layer for communicating over a second network via the first network, wherein the STA is configured to further comprise: means for receiving a signal from an access point, AP, in a first network, means for studying the signal to identify a service set identifier, SSID, to determine whether the AP supports interworking of networks, and means for associating with the first network to access the second network using a Wireless Fidelity, WiFi, interworking function, WIF, element,

wherein the WIF element comprises a Signal Forwarding Function (SFF) and a mobile Internet Protocol (IP) Foreign Agent (FA), and wherein accessing the second network comprises tunneling from the first network to the second network using the mobile IP FA.

16. The STA of claim 15, wherein the STA uses a dynamic host configuration protocol, DHCP, to discover the second network.

17. The STA of claim 15, wherein the STA is configured to receive an interworking IWKSSID.

18. The STA of claim 17, further comprising searching for an IWK SSID from a plurality of SSIDs transmitted by the AP.

19. The STA of claim 15, wherein the SSID is a broadcast ssidbsid from a carrier class WiFi AP.

20. The STA of claim 15, wherein the first network is a WiFi network and the second network is a worldwide interoperability for microwave access, WiMAX, network.

21. An apparatus for interworking of networks, comprising:

means for receiving a signal from an access point, AP, in a first network;

means for studying said signals to identify a service set identifier, SSID;

means for determining whether the AP supports interworking of networks using the SSID to access a second network using the first network; and

means associated with the first network for accessing the second network using a wireless fidelity WiFi Interworking Function (WIF) element, wherein the WIF element comprises a Signal Forwarding Function (SFF) and a mobile Internet Protocol (IP) Foreign Agent (FA), and wherein accessing the second network comprises tunneling from the first network to the second network using the mobile IP FA.

22. The apparatus of claim 21, wherein the SSID is an interworking IWKSSID.

23. The apparatus of claim 21, wherein the first network is a WiFi network and the second network is a worldwide interoperability for microwave access, WiMAX, network.