HK1194900B - Methods, apparatuses and computer program products for inter-system handoff implementing tunneling between source and target access systems - Google Patents

Description

Method, apparatus, and computer program product for implementing inter-system handover of tunnel transmission between source and target access systems

This application is a divisional application of a Chinese patent application filed on July 18, 2008, with application number 200880024970.8 and invention name “Method, device and computer program product for implementing inter-system switching of tunnel transmission between source and target access systems”.

Claiming priority under 35 U.S.C. §119

This application claims the benefit of U.S. Provisional Patent Application No. 60/950,583, filed July 18, 2007, entitled “UMB TO DO HANDOFF,” and is a continuation-in-part of U.S. Patent Application No. 12/047,234, filed March 12, 2008, entitled “METHOD AND APPARATUS FOR HANDOFF BETWEEN ACCESS SYSTEMS,” which also claims the benefit of U.S. Provisional Application No. 60/895,365, filed March 16, 2007, entitled “INTERTECHNOLOGIES INTERWORKING,” all of which are assigned to the assignee of the present application and are hereby specifically incorporated herein by reference.

Technical Field

The following description relates generally to wireless communications and, more particularly, to methods and apparatus for session handover procedures in heterogeneous networks.

Background Art

Wireless network systems have become a ubiquitous means of communicating with others around the world. Wireless communication devices, such as cellular phones and personal digital assistants, have become smaller and more versatile to meet consumer demands and enhance portability and convenience. Consumers have become dependent on these devices, demanding reliable service, expanded coverage, additional services (such as web browsing capabilities), and continued reductions in size and price.

Specifically, with the continued advancement of wireless technology, mobile services are evolving into richer, more compelling mobile convergence services than ever before. As end users demand more and higher-quality multimedia content for all environments, innovations in device technology continue to fuel ever-increasing data consumption. For example, over the past few years, wireless communication technology has evolved from analog-driven systems to digital systems. Typically, in traditional analog systems, analog signals are relayed on forward and reverse links, requiring significant amounts of bandwidth to transmit and receive signals while maintaining adequate quality. Analog signals are continuous in time and space, thus eliminating the need for status messages (e.g., messages indicating the receipt or non-reception of data). In contrast, packet-switched systems convert analog signals into data packets, which are transmitted over physical channels between access terminals and base stations, routers, and the like. Furthermore, the use of packet-switched networks allows digital data to be relayed in its natural form (text, internet data, etc.).

As a result, digital wireless communication systems have become widely adopted to provide a variety of communication services, such as telephony, video, data, messaging, and broadcasting. These systems typically employ access networks, which connect multiple access terminals to a wide area network (WAN) by sharing available network resources. These access networks are typically implemented with multiple access points distributed across a geographic coverage area. Furthermore, this geographic coverage area can be divided into multiple cells, each with an access point. Similarly, the cells can be further divided into multiple sectors. However, within these system architectures, providing efficient handover between multiple access systems that do not utilize the same communication procedures and specifications can be challenging.

Summary of the Invention

The following provides a simplified summary of one or more solutions to provide a basic understanding of these solutions. This summary is not an extensive overview of all contemplated solutions and is neither intended to identify key or important elements of all solutions nor to outline the scope of any or all solutions. Its sole purpose is to provide some concepts of one or more solutions in a simplified form as a prelude to the more detailed description provided later.

The described schemes enable handover of a mobile unit between multiple heterogeneous networks, thereby providing intercommunication between a source access system and a target access system during a session handover using an inter-system handover control component. Thus, the inter-system handover control component can pre-provision tunneling as part of session negotiation between the AT and the target access system, wherein packets are transmitted via the source access system (e.g., to reduce interruptions during the handover process and reduce the need to perform session setup during the handover process). A tunnel can be established from the AT to the target access system, wherein, from the AT's perspective, "mobile-to-target access system" signaling occurs through the tunnel. This tunneling can be further accompanied by establishing additional tunnels to the target access system depending on the type of tunneling involved (e.g., whether the tunneling occurs at the data link layer). The source access system can also specify a target access system based on a pilot report, wherein the AT can then communicate with the target access system and establish a negotiation process.

In a related approach, existing mobility models can be used in IP tunneling between a mobile unit and a target access system to ensure trust and privacy, thereby enabling secure and seamless handovers between heterogeneous networks (e.g., device mobility between networks and administrative domains). Exemplary handovers between these heterogeneous access systems include Ultra Mobile Broadband (UMB) with High-Rate Packet Data (HRPD); WiMax/HRPD; and Long Term Evolution (LTE)/HPRD, where the system architecture can implement Internet Protocol (IP) mobility using Client Mobile IP, thereby actively involving the mobile device in handover preparation. Alternatively, the system can utilize a system that is more network-controlled than the mobile unit itself. This interworking enables handovers between different access systems, while maintaining a continuous call.

According to a related method, in preparation for a handover session, settings are established between the source access system and the target access system. This setup may include discovering the IP address of an interworking security gateway (IWSG) used to ensure the security of transmitted packets. This setup may also include discovering the IP address of the target access system's radio access network (RAN), or RAN-lite. RAN-lite typically consists of only a protocol stack, without radio transceiver functionality. It also supports existing RAN interfaces to core network elements and the real RAN. After pre-establishing a session with RAN-lite, it can be transferred to the real RAN via the existing RAN interface (which is used to support intra-technology inter-RAN handover). This enables, for example, inter-technology handover to the target system without requiring an upgrade to the existing real RAN (to support L3 tunnels from the AT).

According to another approach, RAN-lite is associated with a protocol (e.g., a protocol included in the mobile device and/or IWSG) that enables the mobile device to discover the IP address and establish a tunnel, thereby pre-setting up a session with the target radio system. Depending on the requirements for over-the-air handover, the session negotiated in RAN-lite can be transported over well-known, existing interfaces. Therefore, from the perspective of the radio access network, the access after the handover can be based on the same radio technology, eliminating the need to modify the target radio access system to support handover to heterogeneous radio technologies. RAN-lite can logically function as any other real RAN (e.g., a base station controller) without actually controlling any physical base stations. Once a mobile device has established a tunnel with RAN-lite, it can negotiate a session with RAN-lite, thereby obtaining a session for the target radio technology, and RAN-lite can store a copy of the session for the target radio technology, while the mobile device continues to operate on the source radio technology.

Thus, after an over-the-air handover from a mobile device to a target radio technology, the mobile device can access the target access system's real RAN—e.g., the mobile device accesses the target access system, and the target access system queries the mobile device for a session to negotiate technologies. The mobile unit also provides a Unicast Access Terminal Identifier (UATI) or equivalent identifier that can be used to locate the session, where the UATI from the mobile device can point to a RAN-lite, where the real RAN can be used to obtain a session from the RAN-lite to the real RAN. After obtaining the session, the mobile device can then communicate with the real RAN in the target radio system. It will be appreciated that the real RAN can represent a base station controller with a real connection to a base station.

The inter-system handover control component thus enables tunneling between the AT and the target system, wherein signaling/packets associated with the target system can be forwarded via the source system. According to another approach, L3 tunneling provides the functionality and procedural procedures for transmitting variable-length data sequences between heterogeneous systems while maintaining quality of service and error control. Furthermore, regardless of the direction (e.g., from LTE to HRPD or vice versa), this tunneling is transparent to the underlying access system (e.g., the source of the IP packets is not changed).

In a related aspect, a computer-readable medium is provided having code or computer-executable instructions for: discovering IP addresses of security gateways of a target access system and a source access system; and establishing a secure tunnel to the security gateway and/or any heterogeneous access system.

According to another aspect, a processor is provided that executes instructions and/or includes modules related to: discovering an address of a security gateway; and establishing a tunnel between an AT and a source or target access system.

To accomplish the foregoing and related ends, certain illustrative aspects are described in conjunction with the following description and accompanying drawings. These aspects, however, represent only a few of the various ways in which the principles of the disclosed subject matter may be employed, and the claimed subject matter is intended to encompass all such aspects and their equivalents. Additional advantages and novel features will become apparent from the following detailed description when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

1 illustrates an exemplary inter-system handover control component that provides tunneling of a mobile unit's communication layer from a source access system to a target access system via the source access system.

FIG2 illustrates a detailed handover between an Ultra Mobile Broadband (UMB) and a High Rate Packet Data (HRPD) system via L3 tunneling according to another solution.

FIG3 shows an exemplary handover between HRPD-UMB systems via L3 tunneling.

FIG4 illustrates a related method for transferring a session state from a source access system to a target access system according to one aspect.

FIG5 illustrates a hierarchical arrangement for providing handover between a user device and a source/target access system according to one embodiment.

FIG6 illustrates a call flow according to an exemplary scenario.

FIG. 7 illustrates a system capable of implementing handover in the L3 layer according to one aspect.

FIG8 illustrates a specific system for transmitting data to an access terminal when a handover is requested in the L3 layer;

9 illustrates a system that enables partial data transmission to an access terminal before and after handoff in the L3 layer.

FIG. 10 illustrates a system that can be utilized to receive a handover indication and/or transmit data to an access system accordingly.

DETAILED DESCRIPTION

Various embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are described for the purpose of explanation to provide a thorough understanding of one or more solutions. However, it is apparent that the above solutions can be implemented without these specific details.

As used in this application, the terms "component," "module," "system," and the like are intended to refer to computer-related entities such as, but not limited to, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable, an execution thread, a program, and/or a computer. For example, both an application running on a computing device and the computing device can be components. One or more components can be located within an execution process and/or execution thread, and components can be located on one computer and/or distributed across two or more computers. In addition, these components can be executed from various computer-readable media having various data structures stored thereon. Components can communicate by means of local and/or remote processes, for example, based on signals having one or more data packets (e.g., data from a component interacting with another component in a local system, a distributed system, and/or interacting with other systems by means of signals over a network such as the Internet).

Furthermore, various aspects are described herein in conjunction with terminals, which can be either wired or wireless. A terminal may also be referred to as a system, device, subscriber unit, subscriber station, mobile station, mobile phone, mobile device, remote station, remote terminal, access terminal, user terminal, terminal, communication device, user agent, or user equipment (UE). A wireless terminal may be a cellular phone, satellite phone, cordless phone, Session Initiation Protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless connectivity, computing device, or other processing device connected to a wireless modem. Furthermore, various aspects are described herein in conjunction with base stations. Base stations can be used to communicate with wireless devices and may also be referred to as access points, Node Bs, or other terminology.

Furthermore, the word "or" is intended to mean an inclusive or rather than an exclusive or. That is, unless specified otherwise or clear from the context, the phrase "X employs A or B" is intended to mean any inherently inclusive permutation. That is, any of the following instances would satisfy the phrase "X employs A or B": X employs A; X employs B; or X employs A and B. Furthermore, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more," unless specified otherwise or clear from the context to refer to the singular.

The techniques described herein can be used in a variety of wireless communication systems, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and others. The terms "system" and "network" are often used interchangeably. A CDMA system can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (W-CDMA) and other CDMA variants. cdma2000 also encompasses the IS-2000, IS-95, and IS-856 standards. A TDMA system can implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA system can implement radio technologies such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDM. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE, and GSM are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). Additionally, cdma2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2).

Various aspects or features may be provided in the form of a system that may include multiple devices, components, modules, etc. It is to be understood and appreciated that various systems may include additional devices, components, modules, etc., and/or may not include all of the devices, components, modules, etc. described in conjunction with the figures. Combinations of these methods may also be used.

Figure 1 illustrates a network system 100 that provides handover between multiple heterogeneous networks and intercommunication between a source access system 110 and a target access system 112. It should be understood that this diagram is illustrative in nature, and that the intersystem handover control component may be part of an access terminal (AT). The session between the AT and the target system can be pre-established (with transparency to the source system), for example, via an L3 tunnel. The intersystem handover control component 115 can set up L3 tunneling with a mobile unit 104 operating in dual mode (i.e., operating in both the source access system 110 and the target access system 112). The intersystem handover control component 115 initially enables the mobile unit 104 to obtain the local domain name associated with the source and/or target access systems 110, 112. The intersystem handover component then discovers the IP address of the target access system's 112 security gateway and radio access network (RAN). This gateway serves as the network entry point into the target access system 112. Thus, the inter-system handover control component 115 enables the mobile unit 104 to establish L3 tunneling, wherein signaling and packet transmissions associated with the target access system 112 are subsequently forwarded via the source access system in a seamless operation.

Thus, the inter-system handoff control component 115 can use tunneling to exchange handoff setup and execution packets between the AT 104 and the target access system 112 as part of session negotiation prior to handoff, thereby reducing disruptions during the handoff process and reducing the need to perform session setup during the handoff process. The inter-system handoff control component 115 also enables communication data packets to be transmitted via the source access system 110, which typically does not participate in the negotiation between the AT 104 and the target access system 112.

Figures 2 and 3 illustrate handovers from UMB system 210 to HRPD system 215, and vice versa, via L3 tunneling. In Figure 2, the source access system is represented as UMB system 210, where an access terminal or mobile unit 211 communicates with an evolved base station (eBS) 222. IP packets are forwarded from the eBS to a gateway, and from a home agent to the Internet. In response to a request for handover from UMB 210 (representing the source access system) to HRPD access system 215 (representing the target access system), HRPD setup is initiated, while mobile unit 211 remains in UMB system 210. The intersystem handover control component then implements tunneling between UMB 210 and HRPD 215, with HRPD signaling and associated packet transmission transparently conveyed via L3 tunneling. The L3 tunneling can be carried over IP through UMB system 210.

Path line 250 represents a traffic data line, where mobile unit 211 in UMB 210 requests to discover the radio access network RAN/RAN lite 212 and associated IP address of HRPD 215 in order to prepare and set up communications (e.g., for packet transfer). After discovering the IP address, signals destined for HRPD 215 are transmitted via the RAN lite IP address/packets, where packets pass through access gateway (AGW) 217 in the UMB system before being transferred to RAN lite 212. The packet data serving node (PDSN) 219 serves as the connection point between the HRPD RAN 212 and the IP network, where the interworking security gateway (IWSG) 214 provides security (e.g., IP security) for IPsec tunnel 260, ensuring the security of packet transfers between AT 211 and RAN/RAN lite 212. Gateway 214 serves as the network entry point into the HRPD target access system 215. Additionally, the Session Reference Network Controller (SRNC) 218 typically includes authentication functionality and related configurations, negotiates between the base station 222 and the access terminal 211, and serves as a reference for the base station 222 to obtain information (eg, obtain session information to avoid conflicts during session changes).

Similarly, Figure 3 illustrates another scenario for handover from HRPD 310 to UMB system 315 via Layer 3 tunneling. When a handover request is made from source system HRPD 310 to target system UMB 315, UMB RAN-lite/eBS 312 is discovered and the associated UMB gateways 316 and 325 are identified. For example, initially, UMB RAN-lite 312 is discovered, associated with Interworking Security Gateway (IWSG) 325. Next, after discovering the aforementioned IP address, packets can be sent to that destination IP address via Layer 3 tunneling. This pre-configuration ensures that packets flow to the UMB target system 315.

FIG4 illustrates an exemplary method for performing handovers between multiple heterogeneous systems according to one embodiment. Although the exemplary method is illustrated and described herein as a series of blocks representing various events and/or actions, the subject embodiment is not limited to the illustrated order of the blocks. For example, according to the described embodiment, some actions or events may occur in a different order than illustrated, and/or concurrently with other actions or events. Furthermore, not all illustrated blocks, events, or actions are required to implement the method according to the subject embodiment. Furthermore, it will be appreciated that the exemplary method and other methods according to the described embodiment may be implemented in conjunction with the methods illustrated and described herein, as well as in conjunction with other systems and apparatuses not illustrated and described. Initially, at 410, a change in wireless point conditions is detected that can trigger a handover preparation request from the AT to the target access system. Alternatively, the handover preparation may be triggered by a notification from the target access system to the source access system as a neighbor notification technique. Subsequently, during preparation for the handover session, at 412, settings are established between the AT and the target access system. This setup may include, at 416, discovering the IP address of an interworking security gateway used to secure transmitted packets. This setup may also include discovering the IP address of the RAN/RAN-lite of the target access system at 418. Subsequently, at 420, the inter-system handover control component may implement tunneling between the AT and the target access system, wherein signaling/packets associated with the target system may be forwarded via the source system. Furthermore, at 422, the AT negotiates an air interface session and an IP session with the target access system. Consequently, at 424, a request for radio resources of the target system is received, and then, at 426, radio resources are allocated from the target system to the AT. Consequently, at 430, IP traffic data can be redirected to the AT (or scheduled after 434), and the handover is then completed at 432. Next, at 434, the AT acquires the target system over the air.

The following is a specific example of a fully qualified domain name for a DNS query, where any IP host (such as an AT) can perform a DNS query with a DNS server. Example calls for discovering the security gateway and RAN/RAN-lite of the target system include:

Active handover from UMB to HRPD

<HRPD-subnet>.HRPD.IWSG.<local-domain-name>

<HRPD-subnet>.HRPD.RAN.<local-domain-name>

Active handover from HRPD to UMB

<UMB-ANID>.UMB.IWSG.<local-domain-name>

<UMB-ANID>.UMB.RAN.<local-domain-name>

Active Handover from WiMAX to HRPD

<HRPD-subnet>.HRPD.IWSG.<local-domain-name>

<HRPD-subnet>.HRPD.RAN.<local-domain-name>

Active Handover from HRPD to WiMAX

<WiMAX-APID>.WiMAX.IWSG.<local-domain-name>

<WiMAX-APID>.WiMAX.RAN.<local-domain-name>

Active handover from LTE to HRPD

<HRPD-subnet>.HRPD.IWSG.<local-domain-name>

<HRPD-subnet>.HRPD.RAN.<local-domain-name>

Active handover from HRPD to LTE

<LTE-eNBID>.LTE.IWSG.<local-domain-name>

<LTE-eNBID>.LTE.RAN.<local-domain-name>

The HRPD subnet, UMB ANID, WiMax APID, and LTE-eNBID can be obtained directly over the air by the target access system or can be obtained through the neighbor technology record advertised by the source access system.

Figure 5 shows an exemplary block diagram of the interaction between a user device or access terminal 510, a source access system 540, and a target access system 560. UE 510 includes a target system protocol 511 and a source system protocol 512 to enable dual-mode operation with both systems. This setup enables discovery of the IP address of the IWSG and establishment of an IPsec tunnel. Furthermore, the IP address of the target RAN can be discovered to pre-setup a target RAN session. This setup 500 facilitates session handover from the source access system 540 to the target access system 560 by implementing an IPsec tunnel, using handover preparation and handover execution prior to the handover.

Figure 6 illustrates an exemplary call flow 600 for establishing an IP security tunnel according to another approach. AT 602 initially associates with a source access system 604 and obtains the domain name of a target access system via call 610. AT 602 may then send a Domain Name System (DNS) 606 query to obtain the IP address of an Interworking Security Grid (IWSG) 608 for accessing the target access system. This DNS query may also include discovery of the IP address of the target access system's RAN/RAN-lite. AT 602 may then initiate tunneling to the target access system, where signaling/packets associated with the target system may be forwarded via source system 604. As described above, exemplary handovers between these heterogeneous access systems may include UMB/HRPD, WiMax/HRPD, and LTE/HRPD, where the system architecture may implement IP mobility using Client Mobile IP to proactively involve the mobile or access terminal 602 in handover preparation; alternatively, a system with greater network control than the mobile unit itself may be used. This interworking allows for session handovers between different access systems, preserving the call without dropping the connection.

FIG7 illustrates exemplary heterogeneous wireless communication systems 711 and 721 capable of providing services to a wireless terminal 726. Systems 711 and 721 represent a source access system and a target access system, respectively, and include multiple sectors 702, 704, 708 and 706, 710, 712. Target access system 711 and source access system 721 may utilize different wireless services within these sectors. While these sectors are illustrated as hexagonal and substantially similar in size, it should be appreciated that the size and shape of these sectors may vary depending on the geographic area, the number, size, and shape of obstacles such as buildings, and certain other factors. Access points (base stations, access routers, etc.) 714, 716, 720 are associated with sectors 702, 704, 708, utilizing technology "A" as part of these sectors. Similarly, access points 718, 722, 724 are associated with sectors 706, 712, 710, which utilize technology "B" as part thereof, where technology "B" is different from technology "A."

As the wireless terminal 726 geographically moves in, the signal strength it receives from the target access system 711 may be greater than the signal strength it receives from the source access system 721. It will be appreciated that the wireless terminal 726 can operate in a dual mode with respect to both the source access system 721 and the target access system 711, wherein the inter-system handoff control component 719 can provide tunneling as part of the session negotiation between the AT 726 and the target access system 711 prior to handoff. Thus, as the AT prepares to handoff to the target system, data packets can be transmitted (transparently or non-transparently) via the source access system 721, and then after the handoff is complete, the data packets can be redirected to the target system.

FIG8 illustrates a specific system 800 for implementing data transmission between heterogeneous access systems when a handover is requested via an L3 tunnel established by a mobile unit. The system 800 can be associated with an access point and include a group 802 of multiple components that can communicate with each other to transmit data to an access terminal during a handover between heterogeneous access systems. The group 802 includes a component 804 for determining that an access terminal has requested a handover from a first access system to a second access system. This determination can be performed, for example, by analyzing the identity of the target access system by the access terminal. The identity can include any suitable indication of an IP address that identifies a module of the target access system among one or more other modules of the access system. It will be appreciated that various processes for indicating the identity of the target access system are contemplated for the described approach, and all such processes are intended to be encompassed thereby.

Group 802 also includes a component 806 for receiving data from a first access system and an indication from the first access system of what data should be transmitted next to the access terminal. For example, a timestamp or other sequence number in an RLP packet header may indicate what data should be transmitted next to the access terminal. Group 802 also includes a component 808 for receiving data from a network module, where the data is intended for transmission to the access terminal. Furthermore, the data received from the network module may be an IP-encapsulated data packet associated with a sequence number or timestamp, enabling the second transceiver function to determine what data should be transmitted next to the access terminal. Group 802 may also include a component 810 for transmitting data received from the first access system and the network module in the proper sequence to the access terminal. For example, the second access system may receive data to be transmitted to the access terminal, where the data is non-duplicateable and is to be transmitted in a specific order. System 800 may also include a memory 812 that may store instructions related to executing components 804-810. System 800 enables a new or target access system to begin receiving data in preparation for a handover, even if the source system has not yet relinquished control and data is queued at the target access system. The target access system has the necessary information to reset network layer protocol information and the data being transferred, wherein the handover can be performed at sufficiently high speeds and with minimal downtime without interrupting current data transmission. System 800 can be incorporated into a distributed and/or centralized architecture as part of the system.

FIG9 illustrates a system 900 that can be used to transmit data to an access terminal before or after a handover in the L3 layer. System 900 includes a receiver 902 that receives signals from, for example, one or more receive antennas and performs typical operations on the received signals (e.g., filtering, amplifying, downconverting), and digitizing the conditioned signals to obtain samples. A demodulator 904 can demodulate received pilot symbols and provide them to a processor 906 for channel estimation.

Processor 906 may be a processor dedicated to analyzing information received by receiver component 902 and/or generating information transmitted by transmitter 914. Processor 906 may be a processor for controlling one or more components of system 900 and/or a processor for analyzing information received by receiver 902, generating information transmitted by transmitter 914, and controlling one or more components of system 900. System 900 may include an optimization component 908 that may optimize the performance of a user device before, during, and/or after a handover. Optimization component 908 may be incorporated into processor 906. It will be appreciated that optimization component 908 may include optimization code for performing functions based on the analysis to determine whether to handover from a source access system to a target access system. The optimization code may use artificial intelligence-based methods to perform inference and/or probabilistic and/or statistically based judgments when performing a handover.

System (user device) 900 may also include memory 910, which is operably coupled to processor 906 and stores information about base stations, scheduling information, and the like, such as signal strength information. This information may be used when determining whether and when to request a handover. Memory 910 may also store protocols related to generating lookup tables, etc., so that system 900 can use the stored protocols and/or algorithms to improve system performance. It should be understood that the data storage components (e.g., memories) described herein may be volatile or non-volatile memory, or may include both volatile and non-volatile memory. By way of example and not limitation, non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable PROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM), which may serve as external cache memory. By way of example and not limitation, RAM can be provided in a variety of ways, such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). Memory 910 is intended to include, but is not limited to, these memory types and any other suitable memory types. Processor 906 is connected to symbol modulator 912 and transmitter 914, which transmits the modulated signal.

FIG10 illustrates a system that can be used to receive a handover indication and/or transmit data to an access terminal accordingly. System 1000 includes a base station 1002 having a receiver 1010 that receives signals from one or more user devices 1004 via one or more receive antennas 1006 and transmits signals to one or more user devices 1004 via multiple transmit antennas 1008. In one example, receive antennas 1006 and transmit antennas 1008 can be implemented using a single set of antennas. Receiver 1010 can receive information from receive antennas 1006 and be operatively associated with a demodulator 1012 that demodulates the received information. Receiver 1010 can be, for example, a Rake receiver (e.g., a technique that uses multiple baseband correlators to separately process multipath signal components), an MMSE-based receiver, or some other suitable receiver for distinguishing assigned user devices, as will be appreciated by those skilled in the art. For example, multiple receivers (e.g., one for each receive antenna) may be used, and such receivers may communicate with each other to provide an improved estimate of the user data. The demodulated symbols are analyzed by a processor 1014, similar to the processor described with respect to FIG. 9 , and are coupled to a memory 1016 that stores information related to user device assignments, associated lookup tables, and the like. The receiver outputs for the various antennas may be combined and processed by the receiver 1010 and/or the processor 1014. The modulator 1018 may multiplex the signals for transmission by the transmitter 1020 to the user device 1004 via the transmit antenna 1008.

As used herein, the terms "component," "system," and the like are intended to refer to a computer-related entity, either hardware, a combination of hardware and software, software, or software and/or electromechanical units in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an instance, an executable, a thread of execution, a program, and/or a computer. For example, both an application running on a computer and the computer can be a component. One or more components can reside within a process and/or thread of execution, and a component can be localized on one computer and/or distributed across two or more computers.

The word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be considered preferred or advantageous over other aspects or designs. Similarly, the examples provided herein are provided for clarity of description and ease of understanding only and are not intended to limit the described aspects or portions thereof in any way. It will be appreciated that a variety of additional or alternative examples may be provided, but these have been omitted for simplicity.

Moreover, all or part of the solutions described herein can be implemented as systems, methods, apparatus, or articles of manufacture using standard programming and/or engineering techniques to produce software, firmware, hardware, or any combination thereof for controlling a computer to implement the disclosed solutions. For example, computer-readable media can include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips, etc.), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs), etc.), smart cards, and flash memory devices (e.g., cards, sticks, key drives, etc.). In addition, it should be appreciated that carrier waves can be used to carry computer-readable electronic data, such as those used when sending and receiving emails or when accessing a network such as the Internet or a local area network (LAN). Of course, one of ordinary skill in the art will recognize that various modifications can be made to this configuration without departing from the scope or spirit of the claimed subject matter.

When realizing system and/or method as herein described with software, firmware, middleware or microcode, program code or code segment, they can be stored in the machine-readable medium such as storage component.Code segment can represent any combination of process, function, subroutine, program, routine, subroutine, module, software package, class, or instruction, data structure or program statement.Code segment can be coupled to another code segment or hardware circuit by transmitting and/or receiving information, data, independent variable, parameter, or memory content.Can transmit, forward or transmit information, independent variable, parameter, data etc. with any suitable mode that comprises memory sharing, message passing, token passing, network transmission etc.

For software implementations, the techniques described herein can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described herein. The software code can be stored in a memory unit and executed by a processor. The memory unit can be implemented within the processor or external to the processor. In the case of an external implementation, the memory unit can be communicatively coupled to the processor using various methods known in the art.

The above description includes several examples of the disclosed invention. Of course, it is not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but those skilled in the art will recognize that many other combinations and permutations exist. Accordingly, the present invention is intended to embrace all such changes, modifications, and variations that come within the spirit and scope of the appended claims. Furthermore, with respect to the use of the word "include" in the detailed description or claims, the word is intended to mean including, with a meaning similar to that of the word "comprising" when used as a transitional term in a claim.

Claims (30)

1. A method for inter-system handover in wireless communication between a source access system and a target access system, comprising: The access terminal communicates with the source access system via the air using the protocol of the source access system. The access terminal prepares for handover to the target access system by tunneling signal transmissions associated with the target access system via the source access system. This tunneling transmission is used to negotiate an air interface session with the target access system prior to handover from the source access system. The access terminal communicates with the target access system over the air based at least in part on information received from the target access system as part of the handover preparation, wherein the information received from the target access system is tunneled through the source access system to the access terminal. 2. The method of claim 1, wherein the switching preparation includes: The access terminal sends a request for radio resources at the target access system in order to perform tunnel transmission through the source access system. 3. The method of claim 2, further comprising: The allocation of radio resources at the target access system in response to the request is received via the tunnel transmission through the source access system. 4. The method of claim 1, wherein the transmission of signals associated with the target access system is transparent to the source access system. 5. The method of claim 1, wherein the handover preparation with the target access system is transparent to the source access system. 6. The method of claim 1, further comprising: When operating in the source access system, monitor the pilot signals of the target access system. 7. The method of claim 1, wherein the switching preparation includes: A tunnel is established from the access terminal to the target access system to exchange handover related information. 8. The method of claim 1, further comprising: The address of the target access system is discovered by the access terminal. 9. The method of claim 1, further comprising: When the access terminal is connected to the source access system, the access terminal communicates with the target access system via tunneled secure communication. 10. The method of claim 1, further comprising: The handover information for the target access system is forwarded from the access terminal to the source access system via tunneled secure communication. 11. The method of claim 1, further comprising: The access terminal communicates with the target access system via tunneled secure communication, wherein the tunneled secure communication extends from the access terminal, passes through the source access system, and reaches the target access system. 12. The method of claim 1, wherein the target access system includes a first radio access technology (RAT) and the source access system includes a second RAT. 13. The method of claim 12, wherein the target access system includes a High-Speed Packet Data (HRPD) RAT and the source access system includes a Long Term Evolution (LTE) RAT. 14. The method of claim 12, wherein the target access system includes a Code Division Multiple Access (CDMA) RAT and the source access system includes a Long Term Evolution (LTE) RAT. 15. An apparatus for inter-system handover of wireless communication between a source access system and a target access system, comprising: A module for communicating with the source access system via air in a protocol of the source access system; Module for preparing for handover to the target access system by tunneling signal transmissions associated with the target access system via the source access system, wherein the tunneling transmission is used to negotiate an air interface session with the target access system prior to handover from the source access system; and A module for communicating over the air with the target access system, at least in part based on information received from the target access system as part of the handover preparation, wherein the information received from the target access system is tunneled through the source access system. 16. The apparatus of claim 15, wherein the module for preparing for switching comprises: A module for sending a request for radio resources at the target access system for tunneling through the source access system. 17. The apparatus of claim 16, further comprising: A module for receiving the allocation of radio resources at the target access system in response to the request via the tunnel transmission through the source access system. 18. The apparatus of claim 15, wherein the tunneling of signal transmissions associated with the target access system is transparent to the source access system. 19. The apparatus of claim 15, wherein the handover preparation with the target access system is transparent to the source access system. 20. The apparatus of claim 15, further comprising: A module for monitoring the pilot signals of the target access system when operating in the source access system. 21. The apparatus of claim 15, wherein the module for preparing for switching comprises: A module used to establish a tunnel to the target access system in order to exchange switching information. 22. The apparatus of claim 15, further comprising: A module used to discover the address of the target access system. 23. The apparatus of claim 15, further comprising: A module for communicating with the target access system via tunneled secure communication when connected to the source access system. 24. The apparatus of claim 15, further comprising: A module for forwarding handover-related information for the target access system to the source access system via tunneled secure communication. 25. An access terminal for inter-system handover of wireless communication between a source access system and a target access system, comprising: processor; A memory that communicates electronically with the processor; and Instructions stored in the memory, which can be executed by the processor to perform the following operations: Communicating with the source access system via air using the protocol of the source access system; Preparation for handover to the target access system is performed by tunneling signal transmissions associated with the target access system via the source access system, wherein the tunneling transmission is used to negotiate an air interface session with the target access system prior to handover from the source access system; and The communication with the target access system is conducted over the air, at least in part based on information received from the target access system as part of the handover preparation, wherein the information received from the target access system is tunneled through the source access system. 26. The access terminal of claim 25, wherein the handover preparation includes instructions executable by the processor to perform the following operations: Send a request for radio resources at the target access system for tunneling through the source access system. 27. The access terminal of claim 26, wherein the instructions are executable by the processor to perform the following operations: The allocation of radio resources at the target access system in response to the request is received via the tunnel transmission through the source access system. 28. The access terminal of claim 25, wherein the transmission of signals associated with the target access system is transparent to the source access system. 29. The access terminal of claim 25, wherein the handover preparation with the target access system is transparent to the source access system. 30. The access terminal of claim 25, wherein the instructions are executable by the processor to perform the following operations: When operating in the source access system, monitor the pilot signals of the target access system.