Method for handover and user equipment - Patents.com

Abstract

A method, apparatus, associated computer program product and data structure for determining a handover signaling scheme are provided. A first method includes transmitting an indication of a first protocol version in a handover request message. A second method includes receiving the indication in the handover request message, determining a value of an information element in a handover request acknowledgement message to be transmitted based on the received indication and a second protocol version, the value indicating use of the first signaling scheme or a second signaling scheme different from the first signaling scheme, and transmitting the handover request acknowledgement message including the information element, wherein the handover request acknowledgement message including the information element is received using the first method.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate to determining a signaling scheme for handover. More particularly, embodiments of the present invention relate to methods, apparatus, related computer program products and data structures for determining a signaling scheme for handover. Embodiments of the present invention are applicable, for example, to handovers within Long Term Evolution (LTE) and between evolved Node Bs (eNBs) in the 3rd Generation Partnership Project (3GPP). [Background technology]

[0002] 3GPP decided in LTE Release 8 (Rel-8) to use so-called delta signaling to reduce, for example, the size or configuration of handover command messages (such as Radio Resource Controller (RRC) Connection Reconfiguration messages), which means that if the target eNB does not include, for example, a parameter in the handover command, the User Equipment (UE) can assume that that parameter or functionality will continue after the handover. Summary of the Invention [Problem to be solved by the invention]

[0003] However, in current Universal Mobile Telecommunications Systems (UMTS) (such as so-called 3G systems), this type of scheme is not used for handovers between so-called Radio Network Controllers (RNCs), but for example when the UE is involved in a Radio Network System (RNS) relocation (such as a hard handover), the target RNC can configure the handover command message based on Radio Access Bearer (RAB) information, which means that the target RNC can explicitly include the parameters to be used after the handover.

[0004] Much effort has been devoted to finding ways to solve this problem.

[0005] For example, a full signaling configuration may be used, however, no consideration has been given in 3GPP as to how the target eNB may choose between using so-called delta signaling or full signaling.

[0006] However, in delta signaling, it is assumed that the source eNB and the target eNB use the same RRC protocol release or that the target eNB's RRC protocol release is newer than the source eNB's RRC protocol release. However, additional rules may be needed, for example, if the target eNB's RRC protocol release is earlier than the source eNB's RRC protocol release, since the target eNB cannot continue the later release functionality after handover. Therefore, it can release all additional features and parameters defined in the later release. [Means for solving the problem]

[0007] In view of the above, according to embodiments of the present invention, there is provided a method, apparatus, associated computer program product and data structure for determining a handover signaling scheme.

[0008] In this regard, embodiments of the invention enable one or more of the following: - Defines the logic for the target eNB to select whether to use delta signaling or full signaling. - Allows parameter exchange to assist the target eNB in ​​making said decision. - Avoid complex networks and therefore complex Operation and Management (O&M) configuration efforts. - It provides a simple logic for the target eNB to negotiate when to use delta signaling and when to use full configuration signaling.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 illustrates a method for determining a signaling scheme for handover according to an embodiment of the present invention. [Diagram 2] FIG. 2 illustrates an apparatus for determining a signaling scheme for handover according to an embodiment of the present invention. [Diagram 3] A diagram showing a data structure for determining a signaling method for handover according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0012] It should be noted that in this description, the terms "protocol release, at least one bit, radio resource control connection reconfiguration message, radio resource control protocol, full signaling, and delta signaling" are examples of "protocol version, information element, message sent to UE to command handover, first and second protocol, signaling scheme using a fully configured handover command message (parameters etc.), and signaling scheme using a reduced configured handover command message", respectively, without the latter terms being limited to any special technical or implementation details imposed on the former terms.

[0013] Fig. 1 illustrates a method for determining a handover signaling scheme according to an embodiment of the invention. While the signaling between elements is illustrated horizontally, the vertical configuration of signaling sequences and sequence numbers may reflect the time phase between the signaling. It should be noted that the time phase illustrated in Fig. 1 does not necessarily limit any one of the illustrated method steps to the outlined step sequence. This is especially true for method steps that can be functionally separated from one another. For ease of illustration, in Fig. 1, means or parts that can provide main functions are illustrated with solid functional blocks or arrows and / or regular font, while means or parts that can provide any function are illustrated with dashed functional blocks or arrows and / or italic font.

[0014] 1, the communication system 200 may include a UE 201 and a network 202. The network 202 may further include a source eNB 2021 and a target eNB 2022, where the terms "target" and "source" refer to a handover relationship between the eNBs 2021 and 2022, for example.

[0015] First, in an operation preparation step S0, for example, the UE 201 and the source eNB 2021 can execute a step of performing a measurement procedure and determining the source eNB 2021 for performing a handover (HO).

[0016] 1, in step S1-1, for example, the source eNB 2021 may send an indication (e.g., an enumerated information element) of a first protocol version (e.g., the RRC protocol version of the source eNB 2021) in a handover request message. Then, in step S2-1, for example, the target eNB 2022 may receive the indication of the first protocol version in a handover request message.

[0017] In step S2-2, for example, the target eNB2022 may perform a step of determining, based on an indication (e.g., an RRC indication) of the received first protocol version and second protocol version (e.g., the RRC protocol version of the target eNB2022), a value (e.g., 1 bit) of an information element to be included in a handover request acknowledgement message to be sent (e.g., an RRC connection reconfiguration message that may be encapsulated within the handover request acknowledgement message), indicating the use of either a first signaling scheme (e.g., delta signaling) or a second signaling scheme (e.g., full signaling) different from the first signaling scheme.

[0018] In step S2-3, for example, the target eNB 2022 may perform a step of transmitting a handover request acknowledgement message (which may include an RRC connection reconfiguration message) including an information element indicating the use of one of the first and second signaling schemes (e.g., delta signaling or full signaling). In response, in step S1-2, for example, the source eNB 2021 may perform a step of receiving a handover request acknowledgement message (e.g. including an RRC connection reconfiguration message) including an information element indicating the use of one of the first and second signaling schemes determined based on the first protocol version and the external second protocol version in response to the transmitting step in step S1-1.

[0019] In optional step S1-3, for example, the source eNB 2021 may perform a step of extracting a handover command message including the information element from the received handover request acknowledgement message.

[0020] Next, in step S1-4, for example the source eNB 2021 may perform a step of transmitting a handover command message (eg an RRC connection reconfiguration message) to the user equipment (eg UE 201) after said reception.

[0021] Finally, in step S3-2, for example, UE 201 may perform a step of receiving a handover command message including the information element, and in step S3-2, for example, UE 201 may perform a step of performing a configuration according to the first or second signaling scheme indicated by the information element.

[0022] In a deployment for the target eNB 2022, the above decision steps may be performed during handover preparation. Furthermore, an indication of the first protocol version (such as the RRC protocol version of the source eNB 2021) may be included in a radio resource control container or signaled in an X2 / S1 application signaling protocol.

[0023] In the deployment of both the source eNB 2021 and the target eNB 2022, the first signaling scheme may utilize a radio resource control container defined in the radio resource control specification (e.g., handover preparation information message). In this case, the information element may be set to positive. Furthermore, in this case, the first protocol version (e.g., RRC protocol version of the source eNB 2021) may be higher than the second protocol version (e.g., RRC protocol version of the target eNB 2022). Alternatively, the second signaling scheme may utilize a message defined in the X2 application protocol specification (e.g., handover request message) or the S1 application protocol specification (e.g., handover required message). In this case, the information element may be set to non-positive. Furthermore, in this case, the first protocol version may be equal to or lower than the second protocol version. However, regardless of the signaling scheme, the same information should be transferred from the source eNB 2021 to the target eNB 2022. Furthermore, the protocol version may be configured by a protocol release. Also, the information element may be configured by at least one bit. Furthermore, the handover request acknowledgement message may be constituted by a radio resource control connection reconfiguration message or may encapsulate the radio resource control connection reconfiguration message. Furthermore, the first protocol may be constituted by a radio resource control protocol of the handover source entity, while the indication of the first protocol version may be an enumerated information element. Furthermore, the second protocol may be constituted by a radio resource control protocol of the handover target entity. Finally, the handover command message for full or delta configuration may be constituted by a radio resource control connection reconfiguration message, while the radio resource control container may be constituted by a handover preparation information message.

[0024] 2 illustrates an apparatus (such as a UE 201, a source eNB 2021, and a target eNB 2022) for determining a signaling scheme for handover according to an embodiment of the present invention. In FIG. 2, for ease of explanation, means or parts capable of providing main functions are shown with solid functional blocks or arrows and / or regular font, while means or parts capable of providing optional functions are shown with dashed functional blocks or arrows and / or italic font.

[0025] The UE 201 may include a CPU (or circuitry) 2011 , a memory 2012 , an optional transmitter (or means for transmitting) 2013 , a receiver (or means for receiving) 2014 , and a configurer (or means for configuring) 2015 .

[0026] The source eNB 2021 may include a CPU (or circuitry) 20211 , a memory 20212 , a transmitter (or means for transmitting) 20213 , a receiver (or means for receiving) 20214 , and an optional extractor (or means for extracting) 20215 .

[0027] The target eNB 2022 may include a CPU (or circuit) 20221, a memory 20222, a transmitter (or transmitting means) 20223, a receiver (or receiving means) 20224, and a determiner (or determining means) 20225.

[0028] As indicated by the dashed extensions of the functional blocks of CPU 2011, 20211 or 20221, the configuration means 2015, extraction means 20215 and determination means 20225 (and the transmitting means 2013 and receiving means 2014 of UE 201, the transmitting means 20213 and receiving means 20214 of source eNB 2021, and the transmitting means 20223 and receiving means 20224 of target eNB 2022) may be functions performed in CPU 2011, 20211 or 20221 of UE 201 and / or source eNB 2021 and target eNB 2022, or may be separate functional entities or means.

[0029] The CPU 20x1 (x=1, 21 and / or 22) may be configured, e.g. by software present in the memory 20x2, to process various data inputs and control the functionality of the memory 20x2, the transmitting means 202x3 and the receiving means 20x4 (as well as the configuring means 2015 of the UE 201, the extracting means 20215 of the target eNB 2022 and the determining means 20225). The memory 20x2 may be operable, e.g., to store code means for implementing methods according to embodiments of the present invention when executed, e.g., on the CPU 20x1. It should be noted that the transmitting means 20x3 and the receiving means 20x4 may alternatively be provided as respective integrated transceivers. Furthermore, the transmitter / receiver may be realized as: i) a physical transmitter / receiver, for example for transmitting / receiving over a radio interface (such as between the UE201 and the source entity 2021); ii) a routing entity, for example for transmitting / receiving data packets within a PS (packet switched) network (such as between the source eNB2021 and the target eNB2022 when deployed as separate network entities); iii) a function for writing / reading information to / from a given storage area (such as in the case of a shared / common CPU or memory of the source eNB2021 and the target eNB2022 when deployed as an integrated network entity); or iv) any suitable combination of i) to iii).

[0030] 2, a sending means 20213 of, for example, the source eNB 2021 may perform a step of receiving an indication (e.g., an enumerated information element) of a first protocol version (e.g., an RRC protocol version of the source eNB 2021) in a handover request message. A receiving means 20224 of, for example, the target eNB 2022 may then perform a step of receiving an indication of the first protocol version in the handover request message.

[0031] For example, the determination means 20225 of the target eNB2022 may perform a step of determining a value (e.g., 1 bit) of an information element indicating the use of either a first signaling scheme (e.g., delta signaling) or a second signaling scheme (e.g., full signaling) different from the first signaling scheme, to be included in a handover request acknowledgment message to be sent (e.g., an RRC connection reconfiguration message that may be encapsulated within the handover request acknowledgment message) based on an indication (e.g., an RRC indication) of the received first protocol version and second protocol version (e.g., the RRC protocol version of the target eNB2022).

[0032] Further, for example, the transmitting means 20223 of the target eNB 2022 may perform the step of transmitting a handover request acknowledgement message (which may include an RRC connection reconfiguration message) including an information element indicating the use of one of the first and second signaling schemes (such as delta signaling or full signaling). In response, for example, the receiving means 20214 of the source eNB 2021 may perform the step of receiving a handover request acknowledgement message (e.g. including an RRC connection reconfiguration message) including an information element indicating the use of one of the first and second signaling schemes determined based on the first protocol version and the external second protocol version in response to the transmission made by the transmitting means 20213.

[0033] Optionally, for example, the extracting means 20215 of the source eNB 2021 may perform the step of extracting a handover command message including the information element from the received handover request acknowledgement message.

[0034] Optionally, thereafter, for example the sending means 20213 of the source eNB 2021 may execute a step of sending a handover request acknowledgement message (such as an RRC connection reconfiguration message) to the user equipment (such as the UE 201) after said receiving.

[0035] Finally, a receiving means 2014 of, for example, the UE 201 can perform a step of receiving a handover command message including the information element, and a configuring means 2015 of, for example, the UE 201 can perform a step of performing configuration according to the first or second signaling scheme indicated by the information element.

[0036] In a deployment for the target eNB 2022, the determining means 20225 may be configured to execute during handover preparation. Further, an indication of the first protocol version (such as the RRC protocol version of the source eNB 2021) may be included in a radio resource control container or signaled in an X2 / S1 application signaling protocol.

[0037] In the deployment of both the source eNB 2021 and the target eNB 2022, the first signaling scheme may utilize a radio resource control container defined in the radio resource control specification (e.g., handover preparation information message). In this case, the information element may be set to positive. Furthermore, in this case, the first protocol version (e.g., RRC protocol version of the source eNB 2021) may be higher than the second protocol version (e.g., RRC protocol version of the target eNB 2022). Alternatively, the second signaling scheme may utilize a message defined in the X2 application protocol specification (e.g., handover request message) or the S1 application protocol specification (e.g., handover required message). In this case, the information element may be set to non-positive. Furthermore, in this case, the first protocol version may be equal to or lower than the second protocol version. However, regardless of the signaling scheme, the same information should be transferred from the source eNB 2021 to the target eNB 2022. Furthermore, the protocol version may be configured by a protocol release. Also, the information element may be configured by at least one bit. Furthermore, the handover request acknowledgement message may be constituted by a radio resource control connection reconfiguration message or may encapsulate the radio resource control connection reconfiguration message. Furthermore, the first protocol may be constituted by a radio resource control protocol of the handover source entity, while the indication of the first protocol version may be an enumerated information element. Furthermore, the second protocol may be constituted by a radio resource control protocol of the handover target entity. Finally, the handover command message for full or delta configuration may be constituted by a radio resource control connection reconfiguration message, while the radio resource control container may be constituted by a handover preparation information message.

[0038] Furthermore, the above-mentioned transmitting means 20213, 20223, receiving means 20214, 20224, configuring means 2015, extracting means 20215 and determining means 20225, as well as at least one or more of the UE 101, source eNB 2021 and target eNB 2022, or each of the functions performed therein, may be realized as a chipset, module or subassembly.

[0039] Finally, an embodiment of the present invention also relates to a system which may include a source eNB 2021, a target eNB 2022, and a UE 201 according to the above-described embodiments of the present invention.

[0040] FIG. 3 illustrates a data structure 300 for determining a signaling scheme for a handover, according to an embodiment of the present invention.

[0041] As shown in FIG. 3, the data structure 300 may include an information element 301 that indicates the use of one of a first signaling scheme (e.g., delta signaling) and a second signaling scheme (e.g., full signaling) determined based on a first protocol version (e.g., an RRC protocol version of the source eNB 2021 signaled to the target eNB 2021 during handover preparation) and an external second protocol version (e.g., an RRC protocol version that the target eNB 2022 is configured to support).

[0042] Additionally, the data structure may include an optional header 302 , an optional payload portion 303 , and an optional trailer 304 .

[0043] In the deployment regarding the data structure, the data structure may be configured by a handover request acknowledgement message. Furthermore, the first signaling scheme may utilize a radio resource control container defined in the radio resource control specification (e.g., handover preparation information message). In this case, the information element may be set to positive. Furthermore, in this case, the first protocol version (e.g., RRC protocol version of the source eNB 2021) may be higher than the second protocol version (e.g., RRC protocol version of the target eNB 2022). Alternatively, the second signaling scheme may utilize a message defined in the X2 application protocol specification (e.g., handover request message) or the S1 application protocol specification (e.g., handover required message). In this case, the information element may be set to non-positive. Furthermore, in this case, the first protocol version may be equal to or lower than the second protocol version. However, regardless of the signaling scheme, the same information should be transferred from the source eNB 2021 to the target eNB 2022. Furthermore, the protocol version may be configured by a protocol release. Also, the information element may be constituted by at least one bit. Furthermore, the handover request acknowledgement message may be constituted by a radio resource control connection reconfiguration message or the handover request acknowledgement message may encapsulate the radio resource control connection reconfiguration message. Furthermore, the first protocol may be constituted by a radio resource control protocol of the handover source entity, while the indication of the first protocol version may be an enumerated information element. Furthermore, the second protocol may be constituted by a radio resource control protocol of the handover target entity. Finally, the handover command message for full or delta configuration may be constituted by a radio resource control connection reconfiguration message, while the radio resource control container may be constituted by a handover preparation information message.

[0044] Although not limited to the details below in this section, embodiments of the present invention can be summarized as follows. For example, if a new Channel Quality Indicator (CQI) reporting parameter is defined in Release 9 and a UE is configured with the new CQI reporting parameter in a Release 9 source eNB, then upon handover to a Release 8 eNB, the new CQI reporting parameter should be released. However, since a Release 8 eNB does not support this feature, it has no means to release the feature or correctly interact with a UE that continues to use this feature. Therefore, we consider how to handle handover (HO) when the source and target eNBs use, for example, different protocol versions or releases. Essentially, an embodiment of the present invention provides a mechanism to indicate the RRC (Radio Resource Control) protocol version (release) used at the source eNB, so that, for example, a new parameter can be added to the handover preparation information message, based on which the target eNB can decide whether full or delta signaling is required to successfully complete the HO and indicate this to the UE. In other words, this indicator can tell the UE (User Equipment) whether the target eNB uses the delta or full configuration method, meaning that a specific RRC release version is signaled from the source eNB to the target eNB during handover preparation so that the target eNB can decide which method is or should be used. If the RRC protocol version of the target eNB is equal to or newer than the protocol version used by the source eNB, delta signaling can be supported. To use full signaling, it is proposed to include e.g. one bit for indication in the RRC connection reconfiguration message, e.g. in Release 8 or later. Thus, if the "full signaling indicator" is set to "yes", the UE can clearly understand that the RRC connection reconfiguration message is not based on delta signaling. Since this full signaling may be required when the RRC protocol release of the source eNB is higher than the RRC protocol release of the target eNB, having a "full signaling indicator" for Release 8 or later can solve the problem. This information element may be sent, e.g. in an RRC Connection Reconfiguration message, to the source eNB, e.g. in a Handover Request Acknowledge message, so that the target eNB can make a decision, e.g. during HO preparation, whether to set the "Full Signaling Indicator" to "Yes" or not. In other words, it is proposed to allow the source eNB to indicate the source eNB's RRC protocol release to the target eNB during handover preparation. This information element can be included in the RRC container or signaled over X2 and / or S1 in the X2 and / or S1 application protocols. After the target eNB knows the RRC protocol release used by the source eNB, if this release is higher than the one used by the target eNB or if the target eNB does not understand this release (e.g. because the source eNB's RRC protocol release indicator is higher than the one the target eNB supports), the target eNB can use full signaling. If the source eNB's RRC protocol release is lower or equal to the target eNB's RRC protocol release, the target eNB can use so-called delta signaling. In other words, the signaling of the first protocol version can be done for example by RRC container or X1 / S1 message. This signaling itself does not have to be about delta or full signaling. The source eNB can indicate for example its RRC protocol release via RRC container (e.g. handover preparation information message) or X1 / S1 message (handover request message / handover required message). And gradually the RRC container can be encapsulated in X1 / S2 message. Thus the handover command can be RRC message and the handover request acknowledge message can be X2 message. The handover command message can be in a form that the UE can process, so the handover command can be encapsulated in the handover request acknowledge message and the source eNB can send this handover command to the UE. Finally, the full / delta signaling can be associated to the handover command message configured in this target eNB and sent to the UE via the source eNB. Therefore, a one-bit indicator within this same message (ie, the Handover Command message) can be used to allow the UE to correctly configure the parameters.

[0045] Further Examples As mentioned hereinabove, in the present invention, the following points should be noted. The circuitry may be at least one or a mixture of the following: (a) a pure hardware circuit implementation (such as a pure analog and / or digital circuit implementation); and (b) (where applicable) a combination of circuitry and software (and / or firmware) that: (i) a combination of processor(s); or (ii) processor(s) / portions of software (including digital signal processor(s)), software and memory(s) that cooperate to cause the device as defined above to perform various functions; and (c) A circuit such as a (micro)processor(s) or part of a (micro)processor(s) (a) that requires software and / or firmware for its operation even when the software or firmware is not physically present. The processor may be any processing unit such as a CPU, an arithmetic and logic unit (ALU), a microprocessor unit (MPU), a digital signal processor (DSP), etc., and may be a single-core processor, a dual-core processor, or a multi-core processor. - the program may be embodied by or on any computer program (product), computer readable medium, processor(s), memory(s), circuitry, circuits, random access memory (RAM), read only memory (ROM), and / or data structure(s), such as compiled / uncompiled program (source) code, executable object, (meta)file, etc. - the access technology may be any technology that allows a user equipment to access the access network (or to the base station, respectively). Any current or future technology may be used, such as WiMAX (Worldwide Interoperability for Microwave Access) or WLAN (Wireless Local Area Network), Bluetooth, Infrared, etc., and most of these technologies are wireless access technologies, for example in different radio spectrums, but the access technology in the sense of the present invention may also imply wirebound technologies, such as cable networks or IP-based access technologies, such as fixed lines. - A network may be any equipment, unit or means that enables station entities or other user equipment to connect to and / or use the services offered by an access network, such services including, inter alia, data and / or (audio)visual communication, data downloads, etc. In general, the invention can be applied in a network / user equipment environment that transmits data in data packets and that relies on a data packet-based transmission scheme based for example on the Internet Protocol (IP), but the invention is not limited thereto and can also be applied in any other current or future IP or Mobile IP (MIP) version or more generally in any protocol following similar principles to (M)IPv4 / 6. - User Equipment is any device, unit or means that enables a system user to experience services from an access network. - The method steps which are likely to be realized as software code portions (as an example of an apparatus, device and / or modules thereof, or as an example of an entity comprising an apparatus, circuit and / or modules thereof) and which are executed using a processor in a network element or terminal do not rely on software code and can be configured using any known or later developed programming language, as long as the functionality defined by these method steps is preserved. In general, any method step is suitable to be realized as software or by hardware without changing the idea of ​​the invention in terms of the functions performed. - the method steps and / or apparatus, units or means likely to be realized as hardware components in the above defined apparatus or any module / circuit(s) thereof are hardware independent and may be realized using any known or future developed hardware technology such as MOS (Metal Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor-Transistor Logic) or any hybrid of these, for example using ASIC (Application Specific Integrated Circuit) components, FPGA (Field Programmable Gate Array) components, CPLD (Combined Programmable Logic) components or DSP (Digital Signal Processor) components, and any steps and / or apparatus, units or means likely to be realized as software components may instead be based on any security architecture capable of performing authentication, authorization, keying and / or traffic protection etc. - any equipment, unit, circuit or means (such as any one of the devices defined above or their respective means) may be realised as individual equipment, units or means, but this does not exclude them being realised in a distributed manner throughout the system, as long as the functionality of these equipment, units, circuits or means is maintained. - an apparatus may be represented by a semiconductor chip, a chipset, a (hardware) module comprising said chips or chipsets, or a circuit, but this does not exclude the possibility that the functionality of the apparatus, module or circuit may instead be realized in hardware as software in a (software) module, such as a computer program or computer program product comprising executable software code portions for execution / operation on a processor. - For example, a device may be considered as one device or as an assembly of several devices, depending on whether they are functionally associated with each other or functionally separate from each other but reside within the same device housing.

[0046] According to an embodiment of the present invention, in a first aspect, this object is e.g. receiving an indication of a first protocol version in a handover request message; determining a value of an information element in a handover request acknowledgement message to be sent, the information element indicating the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, based on the received indication of the first protocol version and the second protocol version; transmitting the handover request acknowledgement message including the information element indicating the use of one of the first and second signaling schemes; This is achieved by a method comprising:

[0047] According to a further refinement of the embodiment of the invention defined on the basis of the first aspect above, - said determining step is performed during handover preparation.

[0048] According to an embodiment of the present invention, in a second aspect, this object is e.g. sending an indication of a first protocol version in a handover request message; receiving a handover request acknowledgement message in response to the transmitting step, the handover request acknowledgement message including an information element indicating use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the second signaling scheme being determined based on the first protocol version and an external second protocol version; This is achieved by a method comprising:

[0049] According to a further refinement of the embodiment of the invention defined on the basis of the second aspect above, - extracting from the received handover request acknowledgement message a handover command message including the information element; - the method further comprising the step of, after said receiving, transmitting said handover command message to a user equipment.

[0050] According to a further refinement of the embodiment of the invention defined on the basis of the first and second aspects above, - an indication of the first protocol version is included in a radio resource control container; and - an indication of the first protocol version is signaled in an X2 / S1 application signaling protocol.

[0051] According to an embodiment of the present invention, in a third aspect, this object is e.g. - receiving a handover command message including an information element indicating the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the second signaling scheme being determined based on an external first protocol version and an external second protocol version; configuring according to one of the first and second signaling schemes indicated by the information element; This is achieved by a method comprising:

[0052] According to a further refinement of the embodiment of the invention defined on the basis of the first to third aspects above, - the first signaling scheme utilizes a fully configured handover command message; - said information element is set to the positive; - the first protocol version is higher than the second protocol version; - the second signaling scheme utilizes a reduced configuration handover command message; - said information element is set to non-positive, - the first protocol version is equal to or lower than the second protocol version; - the protocol version is constituted by a protocol release; - the information element is composed of at least one bit; - the handover request acknowledgement message is formed by or encapsulates a radio resource control connection reconfiguration message; - the first protocol is configured by a radio resource control protocol of a handover source entity; - the indication of the first protocol version is an enumerated information element; - the second protocol is configured by a radio resource control protocol of a handover target entity; - the fully configured handover command message comprises a radio resource control connection reconfiguration message; - the delta configuration handover command message is comprised of a radio resource control connection reconfiguration message; - said radio resource control container is constituted by a handover preparation information message.

[0053] According to an embodiment of the present invention, in a fourth aspect, this object is e.g. means for receiving an indication of a first protocol version in a handover request message; means for determining, based on the received indication of the first protocol version and the second protocol version, a value of an information element instructing the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the value being included in a handover request acknowledgement message to be transmitted; means for transmitting the handover request acknowledgement message including the information element indicating the use of one of the first and second signaling schemes; This is achieved by an apparatus comprising:

[0054] According to a further refinement of the embodiment of the invention defined on the basis of the fourth aspect above, - said determining means being adapted to execute during handover preparation;

[0055] According to an embodiment of the present invention, in a fifth aspect, this object is e.g. means for sending an indication of a first protocol version in a handover request message; means for receiving a handover request acknowledgement message in response to the transmitting means, the handover request acknowledgement message including an information element indicating use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the second signaling scheme being determined based on the first protocol version and an external second protocol version; This is achieved by an apparatus comprising:

[0056] According to a further refinement of the embodiment of the invention defined on the basis of the fifth aspect above, - means for extracting from the received handover request acknowledgement message a handover command message including the information element; - means for the apparatus transmitting, after said receiving, said handover command message to a user equipment.

[0057] According to a further refinement of the embodiment of the invention defined on the basis of the fourth and fifth aspects above, - the indication of the first protocol version is included in a radio resource control container; and - the indication of the first protocol version is configured to be signaled in an X2 / S1 application signaling protocol.

[0058] According to an embodiment of the present invention, in a sixth aspect, this object is e.g. means for receiving a handover command message including an information element for instructing the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the first signaling scheme being determined based on an external first protocol version and an external second protocol version; means for configuring according to one of the first and second signaling schemes indicated by the information element; This is achieved by an apparatus comprising:

[0059] According to a further refinement of the embodiment of the invention defined on the basis of the above fourth to sixth aspects, - the first signaling scheme is configured to utilize a fully configured handover command message; - the information element is configured to be set in the affirmative; - the first protocol version is higher than the second protocol version; - the second signaling scheme is configured to utilize a reduced configuration handover command message; - the information element is configured to be set to non-positive; - the first protocol version is equal to or lower than the second protocol version; - the protocol version is constituted by a protocol release; - the information element is composed of at least one bit; - the handover request acknowledgement message is formed by or encapsulates a radio resource control connection reconfiguration message; - the first protocol is configured by a radio resource control protocol of a handover source entity; - the indication of the first protocol version is an enumerated information element; - the second protocol is configured by a radio resource control protocol of a handover target entity; - the fully configured handover command message comprises a radio resource control connection reconfiguration message; - the delta configuration handover command message is comprised of a radio resource control connection reconfiguration message; - the radio resource control container is constituted by a handover preparation information message; at least one or more of the receiving means, determining means, sending means, extracting means, configuring means and said devices are implemented as a chipset, a module or a subassembly.

[0060] According to an embodiment of the present invention, in a seventh aspect, this object is e.g. a receiver configured to receive an indication of a first protocol version in a handover request message; a determiner configured to determine, based on the received indication of the first protocol version and the second protocol version, a value of an information element included in an outgoing handover request acknowledgement message, the information element indicating the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme; a transmitter configured to transmit the handover request acknowledgement message including the information element indicating the use of one of the first and second signaling schemes; This is achieved by an apparatus comprising:

[0061] According to a further refinement of the embodiment of the invention defined according to the seventh aspect above, - A decider is configured to run during handover preparation.

[0062] According to an embodiment of the present invention, in an eighth aspect, this object is e.g. a transmitter configured to transmit an indication of the first protocol version in a handover request message; a receiver configured to receive, in response to the transmitter, a handover request acknowledgement message including an information element indicating the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the second signaling scheme being determined based on the first protocol version and an external second protocol version; This is achieved by an apparatus comprising:

[0063] According to a further refinement of the embodiment of the invention defined according to the eighth aspect above, the apparatus further comprises an extractor configured to extract from the received handover request acknowledgement message a handover command message including the information element; - the apparatus further includes a transmitter configured to transmit, after said receiving, said handover command message to a user equipment.

[0064] According to a further refinement of the embodiment of the invention defined on the basis of the seventh and eighth aspects above, - an indication of the first protocol version is included in a radio resource control container; - the indication of the first protocol version is configured to be signaled in an X2 / S1 application signaling protocol.

[0065] According to an embodiment of the present invention, in a ninth aspect, this object is achieved, for example, by a receiver configured to receive a handover command message including an information element indicating the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the second signaling scheme being determined based on an external first protocol version and an external second protocol version; a configurator configured to perform configuration according to one of the first and second signaling schemes indicated by the information element; This is achieved by an apparatus comprising:

[0066] According to a further refinement of the embodiment of the invention defined on the basis of the seventh to ninth aspects above, - the first signaling scheme is configured to utilize a fully configured handover command message; - the information element is configured to be set in the affirmative; - the first protocol version is higher than the second protocol version; - the second signaling scheme is configured to utilize a reduced configuration handover command message; - the information element is configured to be set to non-positive; - the first protocol version is equal to or lower than the second protocol version; - the protocol version is constituted by a protocol release; - the information element is composed of at least one bit; - the handover request acknowledgement message is formed by or encapsulates a radio resource control connection reconfiguration message; - the first protocol is configured by a radio resource control protocol of a handover source entity; - the indication of the first protocol version is an enumerated information element; - the second protocol is configured by a radio resource control protocol of a handover target entity; - the fully configured handover command message comprises a radio resource control connection reconfiguration message; - the delta configuration handover command message is comprised of a radio resource control connection reconfiguration message; - the radio resource control container is constituted by a handover preparation information message; the receiver, the determiner, the extractor, the configurer and at least one or more of said devices are implemented as a chipset, a module or a subassembly.

[0067] According to an embodiment of the present invention, in a tenth aspect, this object is e.g. An apparatus according to the fourth or seventh aspect, An apparatus according to the fifth or eighth aspect, An apparatus according to the sixth or ninth aspect, This is achieved by a system comprising:

[0068] According to an embodiment of the present invention, in an eleventh aspect, this object is achieved by a computer program product comprising code means for performing the method according to any one of claims 1 to 15 when executed on, for example, a processing means or a module.

[0069] According to an embodiment of the present invention, in a twelfth aspect, this object, when executed on, for example, a processing means or module, receiving an indication of a first protocol version in a handover request message; determining a value of an information element in a handover request acknowledgement message to be sent, the information element indicating the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, based on the received indication of the first protocol version and the second protocol version; transmitting the handover request acknowledgement message including the information element indicating the use of one of the first and second signaling schemes; This is achieved by a computer program comprising code means for carrying out the method comprising:

[0070] According to an embodiment of the present invention, in a thirteenth aspect, this object, when executed on, for example, a processing means or module, sending an indication of a first protocol version in a handover request message; receiving a handover request acknowledgement message in response to the transmitting step, the handover request acknowledgement message including an information element indicating use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the second signaling scheme being determined based on the first protocol version and an external second protocol version; This is achieved by a computer program comprising code means for carrying out the method comprising:

[0071] According to an embodiment of the present invention, in a fourteenth aspect, this object, when executed on a processing means or module, receiving a handover command message including an information element indicating the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, the second signaling scheme being determined based on an external first protocol version and an external second protocol version; configuring according to one of the first and second signaling schemes indicated by the information element; This is achieved by a computer program comprising code means for carrying out the method comprising:

[0072] According to an embodiment of the present invention, in a fifteenth aspect, this object is achieved by a data structure including an information element including an information element indicating the use of one of a first signaling scheme and a second signaling scheme different from the first signaling scheme, determined for example on the basis of the first protocol version and an external second protocol version.

[0073] According to a further refinement of the embodiment of the invention defined under the fifteenth aspect above, - the protocol version is constituted by a protocol release; - the information element is composed of at least one bit; - the data structure is constituted by a handover request acknowledgement message; - the handover request acknowledgement message is formed by or encapsulates a radio resource control connection reconfiguration message; - the first protocol is configured by a radio resource control protocol of a handover source entity; - the indication of the first protocol version is an enumerated information element; - the second protocol is configured by a radio resource control protocol of a handover target entity; - the fully configured handover command message comprises a radio resource control connection reconfiguration message; - the delta configuration handover command message is comprised of a radio resource control connection reconfiguration message; - said radio resource control container is constituted by a handover preparation information message.

[0074] Although the present invention has been described herein with reference to particular embodiments, the present invention is not limited to these embodiments and various modifications may be made to the present invention. [Explanation of symbols]

[0075] 201 UE (user equipment) 202 Network 2021 Source eNB 2022 Target eNB S0 Performs measurement procedures and source eNB determination for handover S1-1 Transmission S1-2 reception S1-3 Extract the handover command message (IE indicates the use of the first / second signaling method) from the handover request acknowledgement message S1-4 Transmission S2-1 Reception S2-2 Determine the IE value [first and second protocol version] that indicates the use of the first / second signaling method S2-3 Transmission S3-1 Reception Configured according to S3-2 1st / 2nd signaling method

Claims

1. 1. A method performed by a user equipment (UE) that supports a first protocol release and a second protocol release that is later than the first protocol release, the method comprising: receiving, from a source base station, a first RRC connection reconfiguration message that configures the UE according to the second protocol release; receiving, from the source base station, a handover command message instructing the UE to handover to a target base station that supports the first protocol release and does not support the second protocol release, the handover command message including a second RRC connection reconfiguration message generated by the target base station, the second RRC connection reconfiguration message including an information element indicating that the UE is going to perform a full configuration, the information element being based on the second protocol release used by the source base station to configure the UE; performing a full configuration according to the first protocol release for handover to the target base station; The method includes:

2. The method of claim 1 , further comprising the step of performing a measurement procedure for a handover.

3. The method of claim 1 , wherein the step of performing the full configuration comprises the step of releasing a current wireless configuration.

4. The method of claim 1 , wherein the step of performing the full configuration comprises releasing parameters configured by the first RRC connection reconfiguration message.

5. 2. The method of claim 1, wherein the first protocol release is 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Rel-8 and the second protocol release is 3GPP LTE Rel-9.

6. The method of claim 1 , wherein the information element is a one-bit information element.

7. The method of claim 1 , further comprising: performing a delta configuration according to the second protocol release for a handover to a second target base station.

8. The method of claim 1 , wherein the source base station is a first evolved Node B (eNB) and the target base station is a second eNB.

9. The method of claim 1 , wherein the handover command message is based on a handover request acknowledgement message from the target base station.

10. 10. The method of claim 9, wherein the handover request acknowledgement message is based on a handover request message from the source base station indicating the second protocol release.

11. A user equipment (UE) that supports a first protocol release and a second protocol release that is later than the first protocol release, receiving, from a source base station, a first RRC connection reconfiguration message that configures the UE according to the second protocol release; receiving a handover command message from the source base station instructing the UE to handover to a target base station that supports the first protocol release and does not support the second protocol release; the handover command message includes a second RRC connection reconfiguration message generated by the target base station, the second RRC connection reconfiguration message includes an information element indicating that the UE is going to perform a full configuration, the information element being based on the second protocol release used by the source base station to configure the UE, and the UE is configured to: The UE further comprises a processor configured to perform full configuration according to the first protocol release for handover to the target base station.

12. The UE of claim 11 , wherein the processor is further configured to perform a measurement procedure for handover.

13. The UE of claim 11 , wherein the processor is further configured to release a current radio configuration as at least part of performing the full configuration.

14. The UE of claim 11 , wherein the processor is further configured to release parameters configured by the first RRC connection reconfiguration message as at least part of performing the full configuration.

15. 12. The UE of claim 11, wherein the first protocol release is 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Rel-8 and the second protocol release is 3GPP LTE Rel-9.

16. The UE of claim 11, wherein the information element is a one-bit information element.

17. The UE of claim 11 , wherein the processor is further configured to perform delta configuration according to the second protocol release for a handover to a second target base station.

18. The UE of claim 11 , wherein the source base station is a first evolved Node B (eNB) and the target base station is a second eNB.

19. The UE of claim 11 , wherein the handover command message is based on a handover request acknowledgement message from the target base station.

20. 20. The UE of claim 19, wherein the handover request acknowledgement message is based on a handover request message from the source base station indicating the second protocol release.

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