GB2506659A

GB2506659A - Managing handover parameters

Info

Publication number: GB2506659A
Application number: GB1217887.7A
Authority: GB
Inventors: Marko Tapani Niemi
Original assignee: Broadcom Corp
Current assignee: Broadcom International Ltd; Broadcom Corp
Priority date: 2012-10-05
Filing date: 2012-10-05
Publication date: 2014-04-09
Also published as: GB201217887D0

Abstract

A user equipment (UE) may receive one or more handover parameters during a handover preparation phase from a network device. This may be in response to the network device receiving a request to handover a communication device from a source cell in a circuit switching domain to a target cell in a packet switching domain. If a handover process is determined to have failed, the current handover parameters may be removed or invalidated. The failure indication may occur after the first failed handover attempt or, after a predetermined time has elapsed without receiving a handover successful message. The handover may be part of a Reverse Single Radio Voice Call Continuity (RSRVCC) process.

Description

Methods and Apparatuses for Managing Handover Parameters

Technical Field

Embodiments of the present invention relate generally to wireless S communications technology and, more particularly, to a method and apparatus for managing handover parameters in response to a handover failure in a communications system.

Background

Currently, Reverse Single Radio Voice Call Continuity (RSRVCC) occurs when a call is to be transferred from a circuit switching (CS) domain to packet switching (PS) domain. In this regard, the call may be changed from a CS call to an Internet Protocol (IP) Multimedia Subsystem (IMS) call. In a handover preparation phase, or during the handover, User Equipment (liE) may be provided with IMS parameters and security parameters.

The IMS and security parameters that are transferred to the liE during the handover phase are related to the call that is going to be handed over. The IMS and security parameters may become obsolete in response to a handover failure. In an instance in which the handover of the liE from a CS domain to the PS domain fails, the liE typically should not continue to store the parameters and should treat the IMS paramctcrs and security paramctcrs as invalid. However, current cxisting solutions typically continue to facilitate storage of the obsolete IMS parameters and security parameters in the liE even in an instance in which the handover fails.

For instance, at present, the IMS and security parameters may continue to be stored by a UE in an instancc in which a handovcr proccdurc fails and the handovcr procedure is not attempted again to the same target, for example, the PS domain.

Additionally, at present, if the RSRVCC handover preparation has been performed, for example, when the IMS and security parameters have been sent to the liE but a handover command is never sent to the UE, the liE may continue to store the obsolete or invalid IMS and security parameters.

In view of the foregoing drawbacks, it may be beneficial to provide a mechanism of managing handover parameters in an instance in which a handover fails.

S Summary

A method, apparatus and computer program product are therefore provided according to an example embodiment in order to provide an efficient and reliable manner of managing handover parameters in an instance in which a handover fails.

An example embodiment may remove or invalidate IMS parameters and/or security parameters in an instance in which a handover (e.g., a RSRVCC handover) or preparation phase of the handover fails and the tiE has received the IMS parameters and/or security parameters related to a call (e.g., a RSRVCC call) from a network device (e.g., a base station).

Additionally, an example embodiment may enable a UE to remove or invalidate IMS parameters and/or security parameters in an instance in which the handover fails in the preparation phase, for example, when a handover command is not sent to the UE from a network device. In this regard, the UE may trigger or start a predetermined time period and upon expiration of the time period, the UE may remove or delete the IMS parameters and/or security parameters since these parameters may be obsolete. The tiE may also remove or invalidate the IMS parameters and/or security parameters even in an instance in which handovcr fails after a handover command is received from the network device. For instance, the UE may remove or invalidate the IMS parameters and/or security parameters upon expiration of the predetermined time period in response to detecting that handover failed afler the handover command is received from the network device.

In an alternative example embodiment, the network device may send an indication to the UE instructing the UE to remove or invalidate the TMS parameters and/or security parameters.

In another alternative example embodiment, a TIE may keep received handover parameters (e.g., RSRVCC parameters (e.g., IMS parameters, security parameters)) stored for a specified time (for example, based on a time period) in order to enable a fast recovery from a failed handover. For instance, in response to detecting a handover failure, the UE may store the IMS parameters and/or security parameters and may start a predefined time period to determine whether the handover is successful upon a second or subsequent handover attempt. In response to S determining that a second or subsequent handover attempt is successful within the predefined time period, the TIE may continue to store and utilize the IMS parameters and/or security parameters. In this regard, the network device may not need to resend the parameters to the liE and instead may restart the handover procedure (e.g., a RSRVCC handover procedure) during the second or subsequent successful handover attempt. On the other hand, in an instance in which the TJE does not detect a successful handover, in response to a second or subsequent handover attempt, during the predefined time period, the UE may remove or invalidate the IMS parameters and/or security parameters.

In one example embodiment, a method is provided that includes receiving one or more handover parameters during a handover preparation phase from a network device in response to the network device receiving a request to handover a communication device from a source cell providing a current communication to the communication device in a circuit switching domain to a target cell providing communications in a packet switching domain. The method of this embodiment also determines whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.

In another example embodiment, an apparatus is provided that includes a processing system, which may be embodied as at least one processor and at least one memory including computer program code. The processing system is arranged to cause the apparatus to at least receive one or more handover parameters during a handover preparation phase from a network device in response to the network device receiving a request to handover the apparatus from a source cell providing a current communication to the apparatus in a circuit switching domain to a target cell providing communications in a packet switching domain. The processing system of this embodiment is also arranged to cause the apparatus to determine whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.

In a further example embodiment, a computer program product is provided S that includes at least one non-transitory computer-readable storage medium having computer-readable program instructions stored therein with the computer-readable program instructions including program instructions, which, when executed by an apparatus, causes the apparatus to perform the steps of: receiving one or more handovcr parameters during a handovcr preparation phase from a nctwork dcvicc in response to the network device receiving a request to handover an apparatus from a source cell providing a current communication to the apparatus in a circuit switching domain to a target cell providing communications in a packet switching domain; and determining whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.

In yet another example embodiment, an apparatus is provided that includes means for receiving one or more handover parameters during a handover preparation phase from a network device in response to the network device receiving a request to handovcr a communication device from a source cell providing a current communication to the communication device in a circuit switching domain to a target cell providing communications in a packct switching domain. The apparatus of this embodiment also includes means for determining whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.

In yet anothcr cxamplc embodiment, a method is provided that includes enabling provision of one or more handover parameters during a handover preparation phase to a communication device in response to receiving a request to handover the communication device from a source cell providing a current communication to the communication device in a circuit switching domain to a target cell providing communications in a packet switching domain. The method of this embodiment also enables provision of an indication to the communication device to trigger the communication device to determine whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.

In another example embodiment, an apparatus is provided that includes a S processing system, which may be embodied by at least one processor and at least one memory including computer program code. The processing system is arranged to cause the apparatus to at least enable provision of one or more handovcr parameters during a handover preparation phase to a communication device in response to receiving a request to handovcr the communication dcvicc from a source cell providing a current communication to the communication device in a circuit switching domain to a target cell providing communications in a packet switching domain. The processing system is also arranged to cause the apparatus to enable provision of an indication to the communication device to trigger the communication device to determine whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.

In a further example embodiment, a computer program product is provided that includes at least one non-transitory computer-readable storage medium having computer-readable program instructions stored therein with the computer-readable program instructions including program instructions, which, when executed by an apparatus, causes the apparatus to pcrform the steps of: provisioning of onc or more handover parameters during a handover preparation phase to a communication device in response to receiving a request to handover the communication device from a source cell providing a current communication to the communication device in a circuit switching domain to a target cell providing communications in a packet switching domain; and provisioning of an indication to the communication device to trigger the communication device to determine whether to remove or invalidate the handovcr parameters in response to detecting that the handovcr, from the source cell to the target cell, failed during one or more handover attempts.

In yet another example embodiment, an apparatus is provided that includes means for enabling provision of one or more handovcr parameters during a handovcr preparation phase to a communication device in response to receiving a request to handover the communication device from a source cell providing a current communication to the communication device in a circuit switching domain to a target cell providing communications in a packet switching domain. The apparatus of this S embodiment also includes means for enabling provision of an indication to the communication device to trigger the communication device to determine whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source ccli to the target cell, failed during one or more handover attcmpts.

Brief Description of the Drawings

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: FIG. is a schematic representation of a system that may benefit from an

example embodiment;

FIG. 2 is a schematic block diagram of an apparatus from the perspective of a base station in accordance with an example embodiment; FIG. 3 is a block diagram of an apparatus that may be embodied by a mobile terminal in accordance with an example embodiment; FIG. 4 is a schematic diagram of a system for providing a mcchanism to manage handover parameters in accordance with one example embodiment; FIG. 5 is a flowchart illustrating operations performed in accordance with one example embodiment; and FIG. 6 is a flowchart of operations performed in accordance with another

example embodiment.

Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

As used in this application, the term circuitry' refers to all of the following: S (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) to combinations of circuits and software (and/or firmware), such as (as applicable): (i) to a combination of proccssor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (e) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

This definition of circuitry' applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term "circuitry" would also cover, for example and if applicable to the particular claim element, a baseband integrated circuit or application specific integrated circuit for a mobile phone or a similar integrated circuit in server, a cellular network device, or other network device.

As defined herein a "computer-readable storage medium," which refers to a non-transitory, physical or tangible storage medium (e.g., volatile or non-volatile memory device), may be differentiated from a "computer-readable transmission medium," which refers to an electromagnetic signal.

Referring now to FIG. I, a system according to an example embodiment is provided. The system of FIG. I includes a first communication device (e.g., mobile terminal 10) that is capable of communication via a serving cell 12, such as a base station, a Node B, an evolved Node B (eNB), a radio network controller (RNC) or other access point, with a network 14 (e.g., a core network). While the network may be configured in accordance with Universal Mobile Telecommunications System (UMTS), Long Term Evolution LTE) or LTE-Advanced (LTE-A), other networks may support the method, apparatus and computer program product of embodiments of the present invention including those configured in accordance with wideband code S division multiple access (W-CDMA), CDMA2000, global system for mobile communications (GSM), general packet radio service (GPRS) and/or the like.

The network 14 may include a collection of various different nodes, devices or functions that may be in communication with each other via corresponding wired and/or wirelcss interfaccs. For exampic, the network may include one or more cells, including serving cell 12 and one or more neighbor cells 16 (designated neighbor cell I, neighbor cell 2, ... neighbor cell n in the embodiment of FIG. 1), each of which may serve a respective coverage area. The serving cell and the neighbor cells could be, for example, part of one or more cellular or mobile networks (e.g., CS domain networks, PS domain networks, etc.) or public land mobile networks (PLMNs). In turn, other devices such as processing devices (e.g., personal computers, server computers or the like) may be coupled to the mobile terminal 10 and/or other communication devices via the network.

A communication device, such as the mobile terminal 10 (also referred to herein as User Equipment (UE) 10), may be in communication with other communication devices or other devices via the serving cell 12, as well as a neighbor cell (e.g., neighbor cell 16) and, in turn, the network 14. In some cases, the communication device may include an antenna for transmitting signals to and for receiving signals from a serving cell and/or a neighbor cell, for example, during a handover (e.g., a RSRVCC handover).

In some example embodiments, the mobile terminal 10 may be a mobile communication device such as, for example, a mobile telephone, portable digital assistant (PDA), pager, laptop computer, or any of numerous other hand held or portable communication devices, computation devices, content generation devices, content consumption devices, or combinations thereof As such, the mobile terminal 10 may include one or more processors that may define processing circuitry either alone or in combination with one or more memories. The processing circuitly may utilize instructions stored in the memory to cause the mobile terminal 10 to operate in a particular way or execute specific functionality when the instructions are executed by the one or more processors. The mobile terminal 10 may also include communication circuitry and corresponding hardware/software to enable S communication with other devices and/or the network 14.

In one embodiment, for example, a neighbor cell 16 and/or the serving cell 12 (also referred to herein as eNB 12 or Node B 12) may be embodied as or otherwise include an apparatus 20 as generically represented by the block diagram of FIG. 2.

Additionally, in one example embodiment, the mobile terminal 10 may be embodied as or otherwise include an apparatus 30 as generically represented by the block diagram of FIG. 3. While the apparatus 20 may be employed, for example, by a serving cell 12, or a neighbor cell 16 and the apparatus 30 may be employed, for example, by a mobile terminal 10, it should be noted that the components, devices or elements described below may not be mandatory and thus some may be omitted in certain embodiments. Additionally, some embodiments may include further or different components, devices or elements beyond those shown and described herein.

As shown in FIG. 2, the apparatus 20 may include or otherwise be in communication with a processing system including, for example, processing circuitry 22 that is configurable to perform actions in accordance with example embodiments describcd herein. The processing circuitry may be configured to perform data processing, application execution and/or other processing and management services according to an example embodiment of the invention. In some example embodiments, the apparatus or the processing circuitry may be embodied as a chip or chip set. In other words, the apparatus or the processing circuitry may comprise one or more physical packages (e.g., chips) including materials, components and/or wires on a structural assembly (e.g., a baseboard). The structural assembly may provide physical strength, conservation of size, and/or limitation of electrical interaction for component circuitry included thereon. The apparatus or the processing circuitry may therefore, in some cases, be configured to implement an embodiment of the present invention on a single chip or as a single "system on a chip." As such, in some cases, a chip or chipsct may constitute means for performing one or more operations for providing the functionalities described herein.

In an example embodiment, the processing circuitry 22 may include a processor 24 and memory 26 that may be in communication with or otherwise control S a device interface 28. As such, the processing circuitry may be embodied as a circuit chip (e.g., an integrated circuit chip) configured (e.g., with hardware, software or a combination of hardware and software) to perform operations described herein in relation to the apparatus 20. In an alternative example embodiment, thc processing circuitry 22 may be cmbodicd in a modem (e.g., cellular modem 21).

The device interface 28 may include one or more interface mechanisms for enabling communication with other devices, such as one or more mobile terminals 10.

In some eases, the device interface may be any means such as a device or circuitry embodied in either hardware, or a combination of hardware and software that is configured to receive and/or transmit data fromito a network and/or any other device or module in communication with the processing circuitry 22. In this regard, the device interface may include, for example, an antenna (or multiple antennas) and supporting hardware and/or software for enabling communications with a wireless communication network and/or a communication modem, such as a cellular modem 21 (e.g., a CS domain modem, a PS domain modem, a IJMTS modem, a LTE modem, etc.), and/or an optional non-cellular modem 23 (e.g., a WiFi modem, WLAN modem, etc.) for enabling communications with other terminals (e.g., WiFi terminals, WLAN terminals, APs, etc).

In an example embodiment, the memory 26 may include one or more non-transitory memory devices such as, for example, volatile and/or non-volatile memory that may be either fixed or removable. The memory may be configured to store information, data, applications, instructions or the like for enabling the apparatus 20 to carry out various functions in accordance with example embodiments of the present invention. For example, the memory could be configured to buffer input data for processing by the processor 24. Additionally or alternatively, the memory could be configured to store instructions for execution by the processor. As yet another alternative, the memory may include one of a plurality of databases that may store a variety of files, contents or data sets. Among the contents of the memory, applications may be stored for execution by the processor in order to carry out the functionality associated with each respective application. In some cases, the memory may be in coninunication with the processor via a bus for passing information among S components of the apparatus.

The processor 24 may be embodied in a number of different ways. For example, the processor may be embodied as various processing means such as one or more of a microprocessor or other processing element, a eoprocessor, a controller or various other computing or processing devices including integrated circuits such as, for example, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), or the 111cc. In an example embodiment, the processor may be configured to execute instructions stored in the memory 26 or otherwise accessible to the processor. As such, whether configured by hardware or by a combination of hardware and software, the processor may represent an entity (e.g., physically embodied in circuitry -in the form of processing circuitry 22) capable of performing operations according to embodiments of the present invention while configured accordingly. Thus, for example, when the processor is embodied as an ASIC, FPGA or the like, the processor may be specifically configured hardware for conducting the operations described herein. Alternatively, as another example, when the processor is embodied as an executor of software instructions, the instructions may specifically configure the processor to perform the operations described herein.

In one embodiment, the mobile terminals 10 may be embodied as or otherwise include an apparatus 30 as generically represented by the bloclc diagram of FIG. 3. In this regard, the apparatus may be configured to provide for communications with a Node B and/or eNB (e.g., serving cell 12) or another terminal(s) via a communications system. While the apparatus may be employed, for example, by a mobile terminal, it should be noted that the components, devices or elements described below may not be mandatory and thus some may be omitted in certain embodiments. Additionally, some embodiments may include further or different components, devices or elements beyond those shown and described herein.

As shown in FIG. 3, the apparatus 30 may include or otherwise be in conmmnication with a processing system including, for example, processing circuitry 32 that is configurable to perform actions in accordance with example embodiments described herein. The processing circuitry may be configured to perform data S processing, application execution and/or other processing and management services according to an example embodiment of the present invention. In some embodiments, the apparatus or the processing circuitry may be embodied as a chip or chip set. In other words, the apparatus or the processing circuitry may comprise one or more physical packages (e.g., chips) including materials, components and/or wires on a structural assembly (e.g., a baseboard). The structural assembly may provide physical strength, conservation of size, and/or limitation of electrical interaction for component circuitry included thereon. The apparatus or the processing circuitry may therefore, in some cases, be configured to implement an embodiment of the present invention on a single chip or as a single "system on a chip." As such, in some cases, a chip or chipset may constitute means for performing one or more operations for providing the functionalities described herein.

In an example embodiment, the processing circuitry 32 may include a processor 34 and memory 36 that may be in communication with or otherwise control a device interface 38 and, in some cases, a user interface 44. As such, the processing circuitry may be embodied as a circuit chip (e.g., an integrated circuit chip) configured (e.g., with hardware, software or a combination of hardware and software) to perform operations described herein. However, in some embodiments taken in the context of the mobile terminal, the processing circuitry may be embodied as a portion of a mobile computing device or other mobile terminal. In an altemative example embodiment, the processing circuitry 32 may be embodied in a modem (e.g., cellular modem 40).

The optional user interface 44 may be in communication with the processing circuitry 32 to receive an indication of a user input at the user interface and/or to provide an audible, visual, mechanical or other output to the user. As such, the user interface in the context of a mobile terminal may include, for example, a keyboard, a mousc, a joystick, a display, a touch screen, a microphone, a speaker, and/or othcr input/output mechanisms.

The device interface 38 may include one or more interface mechanisms for enabling communication with other devices and/or networks, in some cases, the S device interface may be any means such as a device or circuitry embodied in either hardware, or a combination of hardware and software that is configured to receive and/or transmit data from/to a network and/or any other device or module in communication with the processing circuitry 32. In this regard, the device interface may include, for cxamplc, an antenna (or multiple antennas) and supporting hardware and/or software for enabling communications with a wireless communication network and/or a communication modem or other hardware/software for supporting communication via cable, digital subscriber line (DSL), universal serial bus (USB), Ethernet or other methods. In the illustrated embodiment, for example, the device interface includes a cellular modem 40 (e.g., a CS domain modem, a PS domain modem, a IJMTS modem, a LTE modem, etc.) for supporting communications with the eNB 12 and an optional non-cellular modem 42 (e.g., a WiFi modem, WLAN modem, Bluetooth (BT) modem, etc.) for supporting communications with other terminals (e.g., a WiFi station(s), a WLAIN station(s)), etc.).

In an example embodiment, the memory 36 may include one or more non-transitory memory devices such as, for example, volatile and/or non-volatile memory that may be either fixed or removable. The memory may be configured to store information, data, applications, instructions or the like for enabling the apparatus 30 to carry out various functions in accordance with example embodiments of the present invention. For example, the memory could be configured to buffer input data for processing by the processor 34. Additionally or alternatively, the memory could be configured to store instructions for execution by the processor. As yet another alternative, the memory may include one of a plurality of databases that may store a variety of files, contents or data sets. Among the contents of the memory, applications may be stored for execution by the processor in order to carry out the functionality associated with each respective application. In some cases, the memory may be in communication with the processor via a bus for passing information among components of the apparatus.

The processor 34 may be embodied in a number of different ways. For example, the processor may be embodied as various processing means such as one or S more of a microprocessor or other processing element, a coprocessor, a controller or various other computing or processing devices including integrated circuits such as, for example, an ASIC, an FPGA or the like. In an example embodiment, the processor may be configured to execute instructions stored in the memory 36 or othcrwisc acccssiblc to the proccssor. As such, whcthcr configured by hardware or by a combination of hardware and software, the processor may represent an entity (e.g., physically embodied in circuitry -in the form of processing circuitry 32) capable of performing operations according to embodiments of the present invention while configured accordingly. Thus, for example, when the processor is embodied as an ASIC, FPGA or the like, the processor may be specifically configured hardware for conducting the operations described herein. Alternatively, as another example, when the processor is embodied as an executor of software instructions, the instructions may specifically configure the processor to perform the operations described herein.

Referring now to FIG. 4, a schematic block diagram of a system for enabling removal of handover parameters according to an exemplary embodiment is provided.

Thc system 7 may include, among other things, a Node B (e.g., originating Node B 72) in communication with a Radio Network Controller (RNC) 74 via an interface such as, for example, a lub interface. The RNC 74 may be connected to a Serving General Packet Radio Service (GPRS) Support Node (SGSN) 75 via a lu interface.

The system 7 may also include an evolved Node B (e.g., target eNB 73 (e.g., an E-UTRAN Node B)) in communication with an evolved packet core (EPC) 78 which may include one or more mobility management entities (MME5) (not shown) and one or more system architecture evolution (SAE) gateways (not shown). In some example embodiments, the Node B (e.g., originating Node B 72) and the evolved Node B (e.g., target eNB 73 may also be in communication with the FE 70 and other liEs. The EPC 78 may be connected to the SGSN 75 via an S3/S4 interface and the EPC 78 may be connected to a eNB(s) (e.g., eNB 73) via an SI interface. Although FIG. 4 shows one Node B 72 and one cNB 73, the system 7 of FIG. 4 may include any suitable number of Node Bs 72 and eNBs 73 without departing from the spirit and scope of the invention.

The UE 70 may be exemplary of one embodiment of the apparatus 30 (e.g., S liE 10). Additionally, the originating Node B 72 may be exemplary of one embodiment of the serving cell 12 (also referred to herein as origin cell or source cell) (e.g., a Node B 12) and the target cNB 73 may be exemplary of one embodiment of the neighbor ccli 16 (also referred to herein as target cell) (e.g., an cNB 12). In one example embodiment, the source cell may be a Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), or a Universal Terrestrial Radio Access Network (UTRAN) in a CS domain or the like and the target cell may be a UTRAN/FISPA (High Speed Packet Access), or an Evolved-UTRAN (E-UTRAN) in a PS-domain or the like. It should be noted that the system of FIG. 4, may be employed in connection with a variety of other devices, both mobile and fixed, and therefore, embodiments of the invention should not be limited to application on devices that are mobile (e.g., a TIE) or the Node Bs and eNBs of FIG. 4.

The Node B 72 and eNB 73 may provide E-TJITRA user plane and control plane (radio resource control (RRC)) protocol terminations for the UE 70. The Node B 72 and eNB 73 may provide functionality hosting for such functions as radio resource management, radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to UEs in both uplink and downlink, selection of an MME at UE attachment, IP header compression and encryption, scheduling of paging and broadcast information, routing of data, measurement and measurement reporting for configuration mobility, and the like.

The MME may host functions such as distribution of messages to respective cNBs, security control, idle state mobility control, EPS (Evolved Packet System) bearer control, ciphering and integrity protection of access stratum (AS) and non-access stratum (NAS) signaling, and the like. In an exemplary embodiment, the MME of the EPC 78 may receive one or more messages from respective eNBs (e.g., eNB 73) via an SI interface and may send or report the messages to corresponding eNBs (e.g., other eNBs 73) via the Si interfacc. In this rcgard, the MME may exchange one or more messages and data between the EPC 78 and the eNB 73 via the Si interface. The messages may include, but are not limited to, data such as handover requests, handover parameters (e.g., 1MS parameters, security parameters), handover S commands and any other suitable data. In an example embodiment, the messages (e.g., handover requests, handover parameters, handover commands, etc.) may be sent from the eNB 73 to the EPC 78, via the SI interface, and the EPC 78 may provide the messages to the SGSN 75, via the 53/54 interface. The SGSN 75 may provide the messages to the RNC 74 which may provide the messages to the UE 70 via Node B 72.

In one example embodiment, the handover parameters may be call specific parameters (e.g., call specific parameters that are valid during an ongoing call or session). The parameters may include, but arc not limited to, one or more IP addresses (e.g., Internet Protocol version 4 (Ipv4) addresses, IPvô addresses, etc.) and/or IP port(s) and/or one or more codecs (e.g., an Adaptive Multi-Rate (AMR) speech codcc for an IMS call (e.g., a codec (or list of supported codecs) in order to continue a speech call in an IMS of a PS domain) in which a communication (e.g., a call) is connected in an IMS. The security parameters may include, but are not limited to, a nonce msc security parameter any other suitable security parameters. In one example embodiment, the nonce_msc may be a security parameter to secure CS domain signaling/traffic. The noncc msc may be used to derive keys for a PS domain (e.g., of a target cell) with other security parameters such as, for example, a cipher key (CK) (e.g., a CK_CS key) and/or integrity key (1K) (e.g., an 1K_CS key).

In one example embodiment, the Node B 72 may be currently providing communication services (e.g., a call) to UE 70 in the CS domain and may send a handover request (e.g., a CS to PS handover request), via the RNC 74 and SGSN 75, to the EPC 78. The handovcr request may include data requesting handover of the TIE to eNB 73 which may provide communications services (e.g., a voice call, a video call, etc.) in the PS domain to the TJE 70 in response to the UE 70 being successfully handed over to the eNB 73. The SAE gateway may host functions such as termination and switching of certain packets for paging and support of IJE mobility.

In an exemplary embodiment, the EPC 78 may provide connection to a network such as the Internet.

As shown in FIG. 4, the Node B 72 and eNB 73 may each include a memory device 86 (e.g., memory 26). The memory device 86 may include, for example, S volatile and/or non-volatile memory. The memory device 86 may be configured to store information (e.g., handover parameters), data, applications, instructions or the like for enabling the Node B 72 and eNB 73 to early out various functions in accordance with some exemplary embodiments of the invention. The memory device 86 could be configured to buffer input data for processing by the handover managers 80 of the Node B 72 and eNB 73. Additionally or alternatively, the memory device 86 could be configured to store instructions for execution by the handover managers of the Node B(s) and eNB(s). As yet another alternative, the memory device 86 may be, or may include, one of a plurality of databases that store information and/or media content.

Additionally, as shown in FIG. 4, the Node B 72 and cNB 73 may each include a handovcr manager 80 configured to execute functions associated with each corresponding Node B and eNB with respect to receiving information from and/or providing information to the UE 70 and/or other Node Bs and/or eNBs related to, for example, communication format parameters (e.g., handover parameters, transmission format, etc.) of the corresponding Node B and/or eNB and/or neighboring Node Bs and/or eNBs. As such, the handover manager 80 may be any means or device embodied in hardware, software or a combination of hardware and software that is configured to perform the functions of the handover manager 80 as described herein.

In an exemplary embodiment, the handover manager 80 of each of the Node B 72 and eNB 73 may operate under the control of or otherwise be embodied as a processor (e.g., processor 24) or a processing element.

Some example embodiments may include handovcr managers 80 for an optional IP Multimedia Subsystem (IMS) 83. The IMS 83 may identify one or more handover parameters such as, for example, IMS parameters and/or security parameters that should be utilized for a handover (e.g., a RSRVCC handover) of a UB 70 from a CS domain to a PS domain. In one example embodiment, the handover manager 80 of the eNB 72 may not necessarily include the IMS 83 in an instance in which the eNB 72 provides communication services in the CS domain. In this example embodiment the handover manager 80 of the eNB 73 may provide communication services in the PS domain and may include the IMS 83. In other example embodiments, the handover manager 80 of the Node B 72 and the handover manager of the eNB 73 may include the IMS 83. In one example embodiment, the handover managers 80 may provide the IMS parameters to the UE 70 via NAS signaling (e.g., a NAS layer) and may provide the security parameters to the UE 70 via AS signaling (e.g., a AS layer). In othcr example embodiments, the handover managers may provide the IMS parameters and/or the security parameters to the UE via any suitable signaling (e.g., layers of a protocol stack (e.g., a AS layer, a NAS layer, an IF layer, a Transmission Control Protocol (TCP) layer, etc.)).

The lIE 70 may include a processor 82 which may be configured to execute functions with respect to receiving information from and/or providing information to the Node B 72 and/or eNB 73 related to, for example, handover parameters and handover commands of the corresponding Node B and/or eNB and/or neighboring Node Bs and/or eNBs. As such, the processor 82 may be any means or device embodied in hardware, software or a combination of hardware and software that is configured to perform the functions of the processor 82 as described herein. In an exemplary embodiment, the processor 82 may operate under the control of or otherwise be embodied as a processing element (e.g., the processor 34). A processing element such as those described above may be embodied in many ways. For example, the handover managers 80 and/or the processor 82 may be embodied as a processor, a coprocessor, a controller or various other processing means or devices including integrated circuits such as, for example, an ASIC (application specific integrated circuit) or a FPGA (field-programmable gate array). It should be noted that although FIG. 4 illustrates a handover manager as being disposed at each of the Node 72 and eNB 73, the handover manager 80 could alternatively be disposed at another element of the system 7 or the EPC 78 (e.g., the SAE gateway, the MME, a RAN, etc.) that is accessible to the Node B 72 and eNB 73.

In an exemplary embodiment, the handover manager 80 of each of the Node B 72 and eNB 73 may be capable of communication with each other (e.g., via the RNC 74, SGSN 75 and EPC 78)) and/or with the processor 82 (either directly or indirectly).

Accordingly, the tiE 70 may communicate with the handover managers of either or both of the originating Node B 72 (e.g., of a source cell in a GERAN or an UT RAN, etc.) and the target eNB 73 (e.g., of a target cell in an UTRAN-HSPA or an E-UTRAN, etc.) in connection with a potential handover of the tiE 70 from the originating Node B 72 to the target cNB 73, for example, when the tiE 70 moves from a serving area (e.g., cell) associated with the originating Node B 72 to a serving area associated with the target eNB 73. Although communications may be described below as occurring between the Node B 72 and eNB 73 and the tiE 70, it should be understood that communications related to handover as described herein may be assumed to occur via the handovcr manager 80 of the Node B and eNB and the processor 82, respectively.

It should be noted that the terms "originating" and "target" are merely used herein to refer to roles that any Node B and/or eNB may play at various different times in relation to being a source (e.g., originating) cell initially providing service to a UE or a neighboring or destination or (e.g., target) cell to which service is to be transferred to, for example, the tiE moving from the source cell to the neighboring or destination cell. Thus, the terms "originating" and "target" could be applicable to the same Node B and/or cNB at various different times and such terms are not meant to be limiting in any way.

In general terms, some embodiments of the invention may provide that the tiE is informed via the originating Node B 72 (e.g., the cell in which the tiE 70 is located initially or at least prior to a handovcr) as to whether the originating Node B 72 will handover the tiE 70 to the target eNB 73.

In one example embodiment of FIG. 4, the Node B 72 may be providing communication services such as, for example, a call (e.g., a voice call, a video call, etc.) to the UE 70 in a CS domain. The Node B 72 may send a handover request (e.g., an RSRVCC CS to PS handover request) to the EPC 78 in an instance in which the Node B 72 desires to handover the tiE 70 to an eNB such as, for example, eNB 73 providing communications services in the PS domain. The Node B 72 may send the handover request to the EPC 78 (for example, via the RNC 74 and the SGSN 75) in an instance in which the UE 70 moves in an area (e.g., a cell) in which the eNB 73 provides communication services. The EPC 78 may, but need not, send the Node B 72, a response (e.g., a RSRVCC CS to PS handover response) acknowledging receipt of the handover request.

The EPC 78 may communicate with the cNB 73 to initiate the handover of the liE 70 from Node B 72 to eNB 73 in a handover preparation phase. In this regard, the EPC 78 may retrieve one or more handover parameters, including but not limited to one or more IMS parameters and/or security parameters, from the eNB 73. For instance, the handover manager 80 of the eNB 73 may trigger the IMS 83 to provide the handover parameters to the EPC 78. The IMS parameters retrieved by the IMS 83 may indicate one or more IP addresses and/or IP ports that the UE 70 should be switched upon the TiE 70 being handed over to the eNB 73. In one example embodiment, receipt of the handover parameters by the liE 70 from the EPC 78 (for example, via the SGSN 75, RNC 74 and Node B 72) may trigger the processor 82 of the UE 70 to start a predetermined time period or a time period determined by a network device (e.g., EPC 78, eNB 73). For example, the time period may be determined by the network device and the network device may provide the handover parameters and the determined time period to liE 70. In an instance in which the processor 82 of the UE 70 determines that the handover fails before receiving a handover command from the EPC 78 or the eNB 73 (e.g., via the SGSN 75, RNC 74 and Node B 72), the processor 82 of the liE 70 may remove (e.g., delete) or invalidate the received handover parameters (e.g., IMS parameters and/or security parameters).

For instance, in response to the processor 82 of the UE 70 determining that handover failed, before receipt of a handover command, upon expiration of the predetermined time period, the processor 82 of the HE 70 may remove or invalidate the handover parameters. In this regard, in one example embodiment the processor 82 of the liE 70 may delete the handover parameters from a memory (e.g., memory 36).

In alternative example embodiment, a network device such as, for example, the EPC 78 or cNB 73 may send an indication (e.g., a message) to the liE 70 (e.g., via the SGSN 75, RNC 74 and Node B 72). The indication sent to the UE 70 may instruct the TJE 70 remove or invalidate the handover parameters in an instance in which the network device (e.g., EPC 78, eNB 73) determines that the handover failed even before a handover command is received by the tiE 70 from the network device.

The network device may send the indication to the UE 70 via core network signaling (e.g., AS signaling (e.g., a AS layer), NAS signaling (e.g., a NAS layer), or any other signaling (e.g., higher layers ofa protocol stack)). The network device may determine that the handover failed before a handovcr command is sent from the network device to the liE 70. In response to receipt of the indication, the processor 82 of the liE 70 may remove or invalidate the handover parameters.

In another alternative example embodiment, the processor 82 of the tiE 70 may utilize both the predetermined time period and the indication received from the network device to remove or invalidate the handover parameters. For instance, in response to receipt of the handover parameters from the network device (e.g., EPC 78, eNB 73), the processor 82 of the tiE 70 may start the predetermined time period. In an instance in which the processor 82 of the tiE 70 receives an indication from the network device that the handover failed, the processor 82 of the liE 70 may stop the predetermined time period and may remove or invalidate the handover parameters.

On the other hand, in an instance in which the processor 82 of the tiE 70 determines that the handover failed, even before receipt of a handover command, upon expiration of the predetermined time period and that the network device did not send the indication during the predetermined time period, the processor 82 of the TiE 70 may remove or invalidate the handover parameters.

In some example embodiments, the tiE 70 may remove or invalidate one or more handovcr parameters in response to a handovcr (c.g., a RSRVCC handover) failing after receiving a handover command from a network device (e.g., EPC 78, cNB 73), for example, via SGSN 73, the RNC 74 and Node B 72. For examp'e, the tiE 70 may receive the handovcr parameters from the network device during a handover preparation phase. The receipt of the handover parameters may trigger the lIE to start a predetermined time period. During the predetermined time period, the tiE 70 may receive a handovcr command from the network device (for example, via SGSN 75, RNC 74 and Node B 72). The handover command may, but need not, include data indicating that handover of the UE 70 from the Node B 72 (e.g., providing communication services in the CS domain) to the eNB 73 (e.g., providing communications services in the PS domain) is initiated.

In an instance in which the UE 70 determines that the handover failed or in which the network device (e.g., EPC 78, eNB 73) sends an indication to the TiE 70 informing the liE 70 that the handover failed, during the predetermined time, the liE may stop the predetermined time period from running and may remove or invalidate the handover parameters. On the other hand, in an instance in which the processor 82 of the UE 70 has not detected or received an indication from a network device (e.g., EPC 78, eNB 73) that handover was successful upon expiration of the predetermined time period, the processor 82 of the liE 70 may remove or invalidate the handover parameters from the UE 70. In an instance in which the UE receives an indication from the network device that the handover failed, the UE may receive the indication from the network device via an AS layer (e.g., AS signaling), a NAS layer (e.g., NAS signaling) or one more upper layers (e.g., upper layer signaling).

In an alternative example embodiment, in an instance in which a handover fails after the TiE 70 receives a handover command from a network device (e.g., EPC 78, eNB 73), the liE 70 may not necessarily remove the received handover parameters upon the detection of the handover failure. For example, the liE 70 may not remove the handover parameters immediately after the first handover failure but may keep the handover parameters until, for example, a specific time (e.g., based on a predefined time period being run by the liE 70). As such, this approach of not immediately removing the handover parameters upon detection of the first handover failure may enable fast recovery from handover failure since the TiE 70 may utilize the same handover parameters in an instance in which a second or subsequent handover attempt to the target cell by a network device (e.g., EPC 78, eNB 73) is successful.

For instance, in this example embodiment, receipt of the handover parameters by the TiE 70 from the network device (for example, via SGSN 75, RNC 74 and Node B 72) during the handover preparation phase may trigger the processor 82 of the TiE to start a predefined time period. In response to the processor 82 of the liE 70 dctecting that a first handovcr attcmpt failed or receiving an indication from the network device that the haildover failed (e.g., the first handover attempt), the processor 82 of the UE 70 may not stop the predefined time period. Instead, the predefined time period may continue to run and in an instance in which the processor 82 of the UE 70 detects that a second or subsequent handover attempt to the target cell was successful during the continued runnillg of the predefrned time period, the processor 82 of the IJE 70 may utilize the previously received handover parameters to enable fast recovery from the failed handover (e.g., the first failed handover). In this regard, the network device (e.g., EPC 78, cNB 73) may not necd to rcscnd the handover parameters to the UE 70.

In an alternatiye example embodiment, instead of continuing to run the predefined time period in an instance in which a first handover failure is detected, the proccssor 82 of the TilE 70 may rcstart thc predefincd time pcriod. In this rcgard, the processor 82 of the UE 70 may not remove or invalidate the handover parameters in an instance in which the rcstartcd prcdefincd timc pcriod is being run. In an instance in which the processor 82 of the IJE 70 detects that a second or subsequent handover attempt(s) to the target cell was successftil during the restarted predefined time period, the processor 82 of the UE 70 may utilize the previously received handover parameters to enable fast recovery from the failed handover.

In another alternative example embodiment, instead of continuing to run the predefined time pcriod in an instancc in which a first handover failurc is detected, the processor 82 of the TiE 70 may start another designated time period and may stop the running of the predefined time period. In this manner, the processor 82 of the liE 70 may not remove or invalidate the handover parameters in an instance in which the designated time period is started. In response to the processor 82 of the UE 70 detecting that a second or subsequent handover attempt(s) to the target cell was succcssfu during thc dcsignatcd timc pcriod, thc processor 82 of the UE 70 may utilize the previously received handover parameters to enable fast recovery from the failed handover.

In an alternative example embodiment, detection by the processor 82 of the liE 70 of a loss of network (e.g., cell) coverage, or any other trigger in which the processor 82 of the UE 70 may determine that the handover may not occur, may trigger the processor 82 to remove the handover parameters. In this regard, the processor 82 of the liE 70 may stop a predetermined time period in an instance in which the predetermined time period is running and may remove or invalidate the S handover parameters.

In response to the processor 82 of the TiE 70 determining that the handover (e.g., a RSRVCC handover) of the UE 70 from the Node B 72 (e.g., providing communication services in the CS domain) to the eNB 73 (e.g., providing communication scrviccs in thc PS domain) is successifil, the proccssor 82 may stop the predetermined time period from running upon detection that the handover is successfully completed. In an instance in which the network device provides the indication of the successful completion of the handover to the UE 70, the indication may be provided by the network device to the UE 70 via core network signaling (e.g., AS signaling, NAS signaling, other higher layer signaling, etc.). In this regard, the processor 82 may not remove or invalidate the parameters since the handover was successful, at least not while a call (e.g., a voice call, a video call) remains in session or active.

In an instance in which the call is successfully ended or the call failed, (e.g., loss of network coverage) the processor 82 of the liE 70 may remove or invalidate the handover parameters. In this regard, the processor 82 of the liE 70 may stop the predetermined time period in an instance in which the predetermined time pcriod is running when the call (e.g., a RSRVCC call) is ended or fails.

Referring now to FIG. 5, a flowchart is provided of an example method for managing one or more handover parameters. At operation 500, an apparatus (e.g., liE 70 (e.g., apparatus 30)) may include means, such as the processing circuitry 32, the processor 34, the processor 82 or the like, for receiving one or more handover parameters (e.g., IMS parameters, security parameters) during a handovcr preparation phase from a network device (e.g., EPC 78, eNB 73) in response to the network device receiving a request to handover the apparatus from a source cell (e.g. a source cell of originating Node B 72) providing a current communication to the apparatus in a circuit switching domain to a target cell (e.g., a target cell of target eNB 73) providing communications in a packet switching domain. In one example embodiment, the apparatus (e.g., UE 70) may receive the handover parameters from the network device (e.g., EPC 78, eNB 73) via the SGSN 75, RNC 74 and Node B 72.

At operation 505, an apparatus (e.g., IJE 70 (e.g., apparatus 30)) may include S means, such as the processing circuitry 32, the processor 34, the processor 82 or the like, for determining whether to remove or invalidate the handover parameters in response to detecting that the handover, from thc source cell to the target cell, failed during one or more handover attempts.

Rcfcrring now to FIG. 6, a flowchart is provided of an example method for managing handover parameters. At operation 600, an apparatus (e.g., EPC 78, eNB 73 (e.g., apparatus 20)) may include means, such as the processing circuitry 22, the processor 24, the handover manager 80 or the like, for providing one or more handovcr parameters during a handover preparation phase to a communication device (e.g., UE 70 (e.g., apparatus 30)) in response to receiving a request to handover the communication device from a source cell (e.g., a source cell of originating Node B 72) providing a current communication to the communication device in a circuit switching domain to a target cell (e.g., a target cell of target eNB 73) providing communications in a packet switching domain.

At operation 600, an apparatus (e.g., EPC 78, eNB 73 (e.g., apparatus 20)) may include means, such as the processing circuitry 22, the processor 24, the handovcr manager 80 or the like, for providing an indication to the communication device to trigger the communication device to determine whether to remove or invalidate the handover parameters (e.g., IMS parameters and/or security parameters) in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts. The indication may include data speeif'ing that the handover failed. In one example embodiment, the network device (e.g., EPC 78, cNB 73) may provide the handovcr parameters and/or the indication to the communication device (e.g., UE 70) via the SGSN 75, RNC 74 and Node B 72.

It should be pointed out that FIGS. 5 and 6 are flowcharts of a system, method and computer program product according to an example embodiment of the invention.

It will be understood that each block of the flowcharts, and combinations of blocks in the flowcharts, can be implemented by various means, such as hardware, firmware, and/or a computer program product including one or more computer program instructions. For example, one or more of the procedures described above may be embodied by computer program insiructions. In this regard, in an example embodiment, the computer program instructions which embody the procedures described above are stored by a memory device (e.g., memory 26, memory 36, memory device 86) and executed by a processor (e.g., processor 24, processor 34, processor 82, handover manager 80). As will be appreciated, any such computer program instructions may be loaded onto a computer or other programmable apparatus (e.g., hardware) to produce a machine, such that the instructions which execute on the computer or other programmable apparatus cause the functions specified in the flowcharts blocks to be implemented. In one embodiment, the computer program instructions are stored in a computer-readable memory that can direct a computer or other programmable apparatus to flmction in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function(s) specified in the flowcharts blocks. The computer program instructions may also be loaded onto a computer or other programmable apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmablc apparatus implemcnt the functions specified in the flowcharts blocks.

Accordingly, blocks of the flowcharts support combinations of means lbr performing the specified functions. It will also be understood that one or more blocks of the flowcharts, and combinations of blocks in the flowcharts, can be implemented by special purpose hardware-based computer systems which perform the specified functions, or combinations of special purpose hardware and computer instructions.

In an example embodiment, an apparatus for performing the methods of FIGS. and 6 above may comprise a processor (e.g., the processor 24, the processor 34, the processor 82, the handover manager 80) configured to perform some or each of the operations (500 -505, 600 -605) described above. The processor may, for example, be configured to perform the operations (500 -505, 600 -605) by performing hardware implemented logical functions, executing stored instructions, or executing algorithms for performing each of the operations. Alternatively, the apparatus may comprise means for performing each of the operations described above. In this regard, according to an example embodiment, examples of means for performing operations (500 -505, 600 -605) may comprise, for example, the processor 24 (e.g., as means for performing any of the operations described above), the processor 34, the processor 82, the handover manager 80 and/or a device or circuitry for executing instructions or executing an algorithm for processing information as described above.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

Claims 1. A method for managing handover parameters, the method comprising: receiving one or more handover parameters during a handover preparation S phase from a network device in response to the network device receiving a request to handover a communication device from a source cell providing a current communication to the communication device in a circuit switching domain to a target ccli providing communications in a packet switching domain; and determining whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.
2. Thc method of claim 1, wherein the handover parameters comprise one or more call or session specific parameters.
3. The method of claim I or claim 2, wherein the handover parameters comprise one or more Internet Protocol Multimedia Subsystem parameters or one or more security parameters.
4. The method of any one of the preceding claims, wherein the handover parameters comprise at least one of an Internet Protocol address, an Internet Protocol port, a eodec, or a noneemsc.
5. The method of any one of the preceding claims, further comprising: removing or invalidating the handover parameters in response to detecting that the handover failed during a first handover attempt.
6. The method of claim 5, wherein: triggering a start of a predetermined time period, or a time period received from the network device, in response to receiving the handover parameters; and said detecting comprises determining that the handover failed upon expiration of the predetermined time period in an instance in which an indication is not received during the predetermined time period indicating that the handover is successful.
7. The method of claim 5, wherein: said detecting comprises receiving an indication from the network device specif,'ing that the handover failed.
8. The method of claim 7, whcrcin: said receiving the indication comprises receiving the indication from the network device via at least one of an access stratum layer, a non-access stratum layer or an upper layer that is higher than the non-access stratum layer in a protocol stack.
9. The method of claim 3, wherein: said receiving the handover parameters comprises receiving the Internet Protocol Multimedia Subsystem parameters from the network device via a non-access stratum layer and receiving the security parameters from the network device via an access stratum layer.
10 The method of any one of the preceding claims, further comprising: detecting that the handovcr failed prior to receiving a handovcr command from the network device.
11. The method of any one of claim Ito claim 9, further comprising: detecting that the handover failed after receiving a handover command from the network device.
12. The method of any one of the preceding claims, wherein the current communication comprises a voice call or a video call.
13. The method of any one of the preceding claims, further comprising: deciding not to remove or invalidate the handover parameters upon detecting failure of the handover during a first handover attempt in response to detecting that the handover was successful during a second or subsequent handover attempt to the target cell detected during at least one predetermined time period triggered upon S receipt of the handover parameters.
14. The method of claim 13, further comprising: enabling fast recovery from the failure of the handover by utilizing the handovcr parameters upon detecting the successful handover during the second or subsequent handover attempt to the target cell.
15. The method of any one of the preceding claims, wherein the handover comprises a Reverse Single Radio Voice Call Continuity handover.
16. The method of any one of the preceding claims, wherein the source cell is deployed in a Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), or a Universal Terrestrial Radio Access Network (TJTRAN) and the target cell is deployed in a (JTRAN-Fligh Speed Packet Access (FISPA) Network, or an Evolved-UTRAN (E-UTRAN).
17. An apparatus for managing handover parameters, the apparatus comprising: a processing system arranged to cause the apparatus to at least: receive one or more handover parameters during a handover preparation phase from a network device in response to the network device receiving a request to handover the apparatus from a source cell providing a current communication to the apparatus in a circuit switching domain to a target cell providing communications in a packet switching domain; and determine whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.
18. The apparatus of claim 17, wherein the handover parameters comprise one or more call or session specific parameters.
19. The apparatus of claim 17 or claim 18, wherein the handover parameters comprise one or more Internet Protocol Multimedia Subsystem parameters or one or more security parameters.
20. The apparatus of any one of claim 17 to claim 19, wherein the handover parameters comprise at least one of an Internet Protocol address, an Internet Protocol port, a codec, or a noncemsc.
21. The apparatus of any one of claim 17 to claim 20, wherein the processing system is arranged to cause the apparatus to: remove or invalidate the handover parameters in response to detecting that the handover failed during a first handover attempt.
22. The apparatus of claim 21, wherein the processing system is arranged to cause the apparatus to: trigger a start of a predetermined time period, or a time period received from the network device, in response to receiving the handover parameters; and perform the detecting by determining that the handovcr failed upon expiration of the predetermined time period in an instance in which an indication is not received during the predetermined time period indicating that the handover is successfuL
23. The apparatus of claim 21, wherein the processing system is arranged to cause the apparatus to: perform the detecting by receiving an indication from the network device speciing that the handover failed.
24. The apparatus of claim 23, wherein the processing system is arranged S to cause the apparatus to: receive the indication by receiving the indication from the network device via at least one of an access stratum layer, a non-access stratum layer or an upper layer that is higher than the non-access stratum layer in a protocol stack.
25. The apparatus of claim 19, wherein the processing system is arranged to cause the apparatus to: receive the handover parameters by receiving the Internet Protocol Multimedia Subsystem parameters from the network device via a non-access stratum layer and receiving the security parameters from the network device via an access stratum layer.
26. The apparatus of any one of claim 17 to claim 25, wherein the processing system is arranged to cause the apparatus to: detect that the handover failed prior to receiving a handover command from the network device.
27. The apparatus of any one of claim 17 to claim 25, wherein the processing system is arranged to cause the apparatus to: detect that the handover failed after receiving a handover command from the network device.
28. The apparatus of any one of claim 17 to claim 27, wherein the current communication comprises a voice call or a video cafl.
29. The apparatus of any one of claim 17 to claim 28, wherein the processing system is arranged to cause the apparatus to: decide not to remove or invalidate the handover parameters upon detecting failure of the handover during a first handover attempt in response to detecting that the handover was successful during a second or subsequent handover attempt to the target cell detected during at least one predetermined time period triggered upon S receipt of the handover parameters.
30. The apparatus of claim 29, wherein the processing system is arranged to cause the apparatus to: enable fast recovery from the failure of the handover by utilizing the handover parameters upon detecting the successful handover during the second or subsequent handover attempt to the target cell.
31. The apparatus of any one of claim 17 to claim 30, wherein the handover comprises a Reverse Single Radio Voice Call Continuity handover.
32. The apparatus of any one of claim 17 to claim 31, wherein the source cell is deployed in a Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), or a Universal Terrestrial Radio Access Network (UTRAN) and the target cell is deployed in a UTRAN-High Speed Packet Access (HSPA) Network, or an Evolved-UTRAN (E-UTRAN).
33. The apparatus of any one of claim 17 to claim 32, wherein the apparatus comprises User Equipment.
34. A computer readable medium for managing handover parameters comprising a set of instructions, which, when executed on an apparatus, causes the apparatus to perform the steps of: receiving one or more handover parameters during a handover preparation phase from a network device in response to the network device receiving a request to handover the apparatus from a source cell providing a current communication to the apparatus in a circuit switching domain to a targct ccli providing communications in a packet switching domain; and determining whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed S during one or more handover attempts.
35. Thc computcr rcadablc mcdium of claim 34, wherein thc handovcr paramctcrs comprisc onc or more call or session specific parameters.
36. The computer readable medium of claim 34 or claim 35, wherein the handover parameters comprise one or more Internet Protocol Multimedia Subsystem parameters or one or more security parameters.
37. The computer readable medium of any one of claim 34 to claim 36, wherein the handover parameters comprise at least one of an Internet Protocol address, an Internet Protocol port, a codee, or a noneemsc.
38. The computer readable medium of any one of claim 34 to claim 37, further comprising instructions, which, when executed on the apparatus causes the apparatus to perform the additional steps of: removing or invalidating the handover parameters in response to detecting that the handover failed during a first handover attempt.
39. The computer readable medium of claim 38, further comprising instructions, which, when executed on the apparatus causes the apparatus to perform the additional steps of: triggering a start of a predetermined time period, or a time period received from the network device, in response to receiving the handover parameters; and performing the detecting by determining that the handover failed upon expiration of the predetermined time period in an instance in which an indication is not received during the predetermined time period indicating that the handover is successful.
40. The computer readable medium of claim 38, further comprising S instructions, which, when executed on the apparatus causes the apparatus to perform the additional steps of: performing the detecting by receiving an indication from the network device specifting that the handover failed.
41. The computer readable medium of claim 40, further comprising instructions, which, when executed on the apparatus causes the apparatus to perform the additional steps of: receiving the indication by receiving the indication from the network device via at least one of an access stratum layer, a non-access stratum layer or an upper layer that is higher than the non-access stratum layer in a protocol stack.
42. The computer readable medium of claim 36, further comprising instructions, which, when executed on the apparatus causes the apparatus to perform the additional steps of: receiving the handover parameters by receiving the Internet Protocol Multimcdia Subsystem parameters from the network device via a non-access stratum layer and receiving the security parameters from the network device via an access stratum layer.
43. The computer readable medium of any one of claim 34 to claim 42, further comprising instructions, which, when executed on the apparatus causes the apparatus to perform the additional steps of: detecting that the handover failed prior to receiving a handover command from the network device.
44. The computer readable medium of any one of claim 34 to claim 42, further comprising instructions, which, when executed on the apparatus causes the apparatus to perfbrm the additional steps of: detecting that the handover failed after receiving a handover command from the network device.
45. The computer readable medium of any one of claim 34 to claim 44, wherein the current communication comprises a voice call or a video call.
46. The computer readable medium of any one of claim 34 to claim 45, further comprising instructions, which, when executed on the apparatus causes the apparatus to perform the additional steps of: deciding not to remove or invalidate the handover parameters upon detecting failure of the handover during a first handover attempt in response to detecting that the handover was successful during a second or subsequent handover attempt to the target cell detected during at least one predetermined time period triggered upon receipt of the handover parameters.
47. The computer readable medium of claim 46, further comprising instructions, which, when executed on the apparatus causes the apparatus to perform thc additional steps of: enabling fast recovery from the failure of the handover by utilizing the handover parameters upon detecting the successful handover during the second or subsequent handover attempt to the target cell.
48. The computer readable medium of any one of claim 34 to claim 37, wherein the handover comprises a Reverse Single Radio Voice Call Continuity handover.
49. The computer readable medium of any one of claim 34 to claim 48, wherein the source cell is deployed in a Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), or a Universal Terrestrial Radio Access Network (UTRAN) and the target cell is deployed in a UTRAN-High Speed Packet Access (HSPA) Network, or an Evolved-UTRAN (E-IJTRAN).
50. A method for managing handover parameters, the method comprising: enabling provision of one or more handover parameters during a handover preparation phase to a communication device in response to receiving a request to handovcr thc communication device from a source cell providing a current communication to the communication device in a circuit switching domain to a target cell providing communications in a packet switching domain; and enabling provision of an indication to the communication device to trigger the communication device to determine whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.
51. The method of claim 50, wherein the indication comprises data specifying that the handover failed.
52. The method of claim 50 or claim 51, wherein the handover parameters comprise onc or morc call or session specific paramctcrs.
53. The method of any one of claim 50 or claim 52, wherein the handover parameters comprise one or more Internet Protocol Multimedia Subsystem parameters or one or more security parameters.
54. The method of any one of claim 50 or claim 53, wherein the handover parameters comprise at least one of an Internet Protocol address, an Internet Protocol port, a codec, or a noneemsc.
55. The method of claim 53, further comprising: enabling provision of the indication by providing the indication to the communication device via at least one of an access stratum layer, a non-access stratum layer or an upper layer that is higher than the non-access stratum layer in a protocol stack.S56. The method of claim 53, further comprising: enabling provision of the handover parameters by providing the Internet Protocol Multimedia Subsystem parameters to the communication device via a non-access stratum layer and providing the sccurity parameters to the communication device via an access stratum layer.57. The method of any one of claim 51 to claim 56, further comprising: enabling provision of a message to the communication device speciring that the handover was successful during a second or subsequent handover attempt to the target cell to trigger the communication device to utilize the handover parameters, during a predetermined time period, to recover from an initial failure of the handover that occurred during a first handover attempt to the target cell.58. The method of any one of claim 50 to claim 57, wherein the current communication comprises a voice call or a video call.59. The method of any one of claim 50 to claim 58, wherein the handover comprises a Reverse Single Radio Voice Call Continuity handover.60. The method of any one of claim 50 to claim 59, wherein the source cell is deployed in a Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), or a Universal Terrestrial Radio Access Network (IJTRAN) and the target cell is deployed in a IX[RM4-High Speed Packet Access (HSPA) Network, or an Evolved-IX[RAN (E-IJ[RAN).61. An apparatus for managing handover parameters, the apparatus comprising: a processing system arranged to cause the apparatus to at least: enable provision of one or more handover parameters during a handover S preparation phase to a communication device in response to receiving a request to handover the communication device from a source cell providing a current communication to thc communication dcvicc in a circuit switching domain to a targct ccli providing communications in a packet switching domain; and enablc provision of an indication to thc communication dcvicc to triggcr the communication device to determine whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.62. The apparatus of claim 61, wherein the indication comprises data speci'ing that thc handovcr failed.63. The apparatus of claim 61 or claim 62, wherein the handover parameters comprise one or more call or session specific parameters.64. Thc apparatus of any onc of claim 61 or claim 64, wherein the handover parameters comprise one or more Internet Protocol Multimedia Subsystem parameters or one or more secunty parameters.65. The apparatus of any one of claim 61 or claim 64, wherein the handovcr paramcters comprisc at least one of an Internet Protocol address, an Internet Protocol port, a codee, or a noneemsc.66. The apparatus of claim 64, wherein the processing system is arranged to cause the apparatus to: enable provision of the indication by providing the indication to the communication device via at least one of an access stratum layer, a non-access stratum layer or an upper layer that is higher than the non-access stratum layer in a protocol stack.67. The apparatus of claim 64, wherein the processing system is arranged S to cause the apparatus to: enable provision of the handover parameters by providing the Internet Protocol Multimedia Subsystem parameters to the communication device via a non-access stratum layer and providing the security parameters to the communication device via an access stratum layer.68. The apparatus of any one of claim 61 to claim 67, wherein the processing system is arranged to cause the apparatus to: enable provision of a message to the communication device specifying that the handover was successful during a second or subsequent handover attempt to the target cell to trigger the communication device to utilize the handovcr parameters, during a predetermined time period, to recover from an initial failure of the handover that occurred during a first handover attempt to the target cell.69. The apparatus of claims any one of claim 61 to claim 68, wherein the current communication comprises a voice call or a video call.70. The apparatus of any one of claim 61 to claim 69, wherein the handover comprises a Reverse Single Radio Voice Call Continuity handover.71. The apparatus of any one of claim 61 to claim 70, wherein the source cell is deployed in a Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), or a Universal Terrestrial Radio Access Network (UTRAN) and the target cell is deployed in a UfRAN-High Speed Packet Access (HSPA) Network, or an Evolved-IX[RAN (E-UTRAN).72. A computer readable medium for managing handover parameters comprising a set of instructions, which, when executed on a network device causes the network device to perform the steps of: enabling provision of one or more handover parameters during a handover S preparation phase to a communication device in response to receiving a request to handover the communication device from a source cell providing a current communication to the communication device in a circuit switching domain to a target ccli providing communications in a packet switching domain; and enabling provision of an indication to the communication dcvicc to trigger thc communication device to determine whether to remove or invalidate the handover parameters in response to detecting that the handover, from the source cell to the target cell, failed during one or more handover attempts.73. The computer readable medium of claim 72, wherein the indication comprises data specii,'ing that the handover failed.74. The computer readable medium of claim 72 or claim 73, wherein the handover parameters comprise one or more call or session specific parameters.75. The computer readable medium of any one of claim 72 to claim 74, wherein the handovcr parameters comprise one or more Intcrnct Protocol Multimedia Subsystem parameters or one or more security parameters.76. The computer readable medium of any one of claim 72 to claim 75, wherein the handovcr parameters comprise at least one of an Internet Protocol address, an Intemet Protocol port, a codec, or a noncemsc.77. The computer readable medium of claim 75, further comprising instructions, which, when executed on the network device causes the network device to perform the additional steps of enabling provision of the indication by providing the indication to the communication device via at least one of an access stratum layer, a non-access stratum layer or an upper layer that is higher than the non-access stratum layer in a protocol stack.S78. The computer readable medium of claim 75, further comprising instructions, which, when executed on the network device causes the network device to perform the additional steps of: cnabling provision of thc handovcr parameters by providing the Intcmct Protocol Multimedia Subsystem parameters to the communication device via a non-access stratum layer and providing the security parameters to the communication device via an access stratum layer.79. The computer readable medium of any one of claim 72 to claim 78, further comprising instructions, which, when executed on the network device causes the network device to perform the additional steps of: enabling provision of a message to the communication device speci'ing that the handover was successful during a second or subsequent handover attempt to the target cell to trigger the communication device to utilize the handover parameters, during a predetermined time period, to recover from an initial failure of the handover that occurred during a first handover attempt to the target cell.80. The computer readable medium of any one of claim 72 to claim 79, wherein the current communication comprises a voice call or a video call.81. The computer readable medium of any one of claim 72 to claim 80, wherein the handover comprises a Reverse Single Radio Voice Call Continuity handover.82. The computer readable medium of any one of claim 72 to claim 81, wherein the source cell is deployed in a Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), or a Universal Terrestrial Radio Access Network (UTRAN) and the target cell is deployed in a UTRAN-High Speed Packet Access (HSPA) Network, or an Eyolyed-UTRAN (E-IJTRAN).S