(19)
(11)EP 2 832 149 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
16.01.2019 Bulletin 2019/03

(21)Application number: 12717065.2

(22)Date of filing:  30.03.2012
(51)International Patent Classification (IPC): 
H04W 36/00(2009.01)
H04W 92/20(2009.01)
(86)International application number:
PCT/EP2012/055837
(87)International publication number:
WO 2013/143610 (03.10.2013 Gazette  2013/40)

(54)

DEVICES, METHODS AND COMPUTER PROGRAM PRODUCTS FOR AN IMPROVED HANDOVER IN INTER-SITE CARRIER AGGREGATION SCENARIOS

VORRICHTUNGEN, VERFAHREN UND COMPUTERPROGRAMMPRODUKTE FÜR VERBESSERTE WEITERREICHUNG IN STANDORTÜBERGREIFENDEN TRÄGERAGGREGATIONSSZENARIEN

DISPOSITIFS, PROCÉDÉS ET PRODUITS PROGRAMMES D'ORDINATEUR POUR UN TRANSFERT AMÉLIORÉ DANS DES SCÉNARIOS D'AGRÉGATION DE PORTEUSES INTER-SITES


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
04.02.2015 Bulletin 2015/06

(73)Proprietor: Nokia Solutions and Networks Oy
02610 Espoo (FI)

(72)Inventors:
  • VESTERINEN, Seppo Ilmari
    FI-90460 Oulunsalo (FI)
  • PEKONEN, Johanna Katariina
    FI-02110 Espoo (FI)
  • KOSKINEN, Henri Markus
    FI-02600 Espoo (FI)

(74)Representative: Style, Kelda Camilla Karen et al
Page White & Farrer Bedford House John Street
London, WC1N 2BF
London, WC1N 2BF (GB)


(56)References cited: : 
WO-A1-2011/100492
GB-A- 2 472 789
WO-A2-2011/111973
GB-A- 2 479 534
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Field of the invention



    [0001] The present invention relates to devices, methods and computer program products for an improved handover in inter-site carrier aggregation scenarios. In particular, the present invention relates to such devices, methods and computer program products applicable in mobile communication systems operating based on carrier aggregation, in which a primary cell/carrier is relocated during a handover in an inter-site carrier aggregation scenario.

    Background



    [0002] Mobile data transmission and data services are constantly making progress. With the increasing penetration of such services, a terminal apparatus such as a user equipment UE (or mobile station MS, or the like; different names may apply for respective different standards) is capable of communicating using multiple frequencies or frequency bands and accessing various services. Data throughput is becoming more and more important in view of an increasing amount of data to be conveyed or carried for those services. According to one aspect to increase data throughput, a terminal UE is supplied or served from e.g. plural sources (sites) (e.g. bases stations BS or NodeB's, NB or evolved NodeBs, eNB) using plural carriers in carrier aggregation (CA). This is also referred to as inter-site carrier aggregation if the carriers are provided via distinct sites (in contrast to intra-site carrier aggregation in which one site, e.g. eNB, aggregates the plural carriers "alone").

    [0003] WO2011/100492 A1 is mainly concerned with how to split data between cells based on bandwidth availability. GB2 472789 A discloses that for LTE-Advanced, during handover, the target eNB will tell the user via the source eNB which Component Carriers (CCs) the UE will be assigned to in the target cell.

    [0004] In the following, aspects of the invention will be exemplarily described. In order to enhance legibility and understandability of the invention, for explanatory purposes only, reference is made to the communication system of LTE or LTE-A (Long Term Evolution, LTE-Advanced). However, reference to such specific system and using of specific signalling names or channel names is not intended to limit the present invention to those specific examples. Rather, the principles of the present invention can be transferred to any other communication system adopting different channel/signalling names as LTE/LTE-A.

    [0005] Along with the development of LTE system, high-speed data service has been treated as one of the most important requirements. Especially for local area network, higher data rate is expected from user's perspective. How to provide local service with high speed data rate has become a hot topic in 3GPP (3rd Generation Partnership Project).

    [0006] LTE-LAN (LTE-Local Area Network) is a research activity to compete with world-wide popular WiFi© or WLAN (Wireless Local Area Network) technique. LTE-LAN is basically assumed to be based on LTE technology, but is more focused on some local area use cases and scenarios. LTE-LAN is expected to provide high performance service for users with low cost, and is expected to become a competitor to WiFi©.

    [0007] Applicant is involved in investigating in such area, with a focus on potential LTE local area architectures as one of plural research topics. One of the most promising local area concepts identified in such preliminary works is the architecture based on the LTE-LAN (which is currently referred to as "LTE Hi-concept").

    [0008] Basic assumptions in this concept are:
    • Dual band operation in that local area and wide area accesses are using different radio bands,
    • Autonomous (local area) operation to mobile core network in that the usage of LTE-LAN network is transparent to a core network for simplicity and for keeping the signaling load low,
    • Offloading of LTE wide area network resources (EPS (Evolved Packet System) Bearer Services) to use LTE-LAN network resources in control of the serving eNB of the UE at E-UTRAN level (Evolved Universal Terrestrial Radio Access Network).


    [0009] At the moment, in 3GPP Rel-12 and above there is also some interest in studying Inter-Site Carrier Aggregation with LTE, where a Primary Component Carrier (PCC PCell or primary Cell) is transmitted via e.g. a macro eNB (PCell or primary Cell) and one or more Secondary component carrier (SCCs, SCells or Secondary Cells) is transmitted via e.g. one or more pico cell(s) (representing a SCell or Secondary Cell). Note that as used herein below 'PCell/eNB' is designated to denote a primary eNB and 'SCell BS' is designated to denote a secondary base station, and so on, as also the primary node may provide also SCells in Rel-10 fashion alongside those provided from the secondary node(s). Thus, there is only one Pcell for the UE. Apart from that, any base station can transmit several SCells to that UE. "Inter-site" thus means that at least one SCell is not co-sited with the PCell.

    [0010] In general, the mentioned "LTE-Hi concept" may support Inter-Site and "multi-radio" CA, where a serving eNB is in a role of a primary cell, PCell, and "LTE-Hi" Access Points (APs) are each in a role of a respective secondary cell, SCell.

    [0011] In the LTE-LAN or Inter-Site CA concepts targeted for 3GPP Rel-12, a terminal UE may move within the network coverage, so that there may be situations in which a current SCell(the pico cell or the LTE-LAN AP) has proper signal but the Serving macro eNB or the PCell is not any longer anymore the best cell. This will necessitate in an Inter eNB handover/PCell Relocation procedure to be carried out.

    [0012] Though, so far in the context of Inter Site CA studies, there have not been any discussions known by the inventors about such a scenario, because the CA scenario considered in 3GPP so far are assuming PCell and SCell being controlled by the same eNB (Intra-site CA).

    [0013] In 3GPP standardization, the Inter Site Carrier Aggregation is not supported before to the coming Rel-12 due to an assumption that a backhaul link (the X2 interface) between eNBs has constrains in terms of latency and capacity (3GPP TR 36.814). For such reason, inter-site CA remained unconsidered (omitted) so far.

    [0014] A reason for this is that the current Intra Site Carrier Aggregation is supposed to happen at the radio link layer (below RLC in LTE radio stack), so that the fast radio control loop on all the CCs must be terminated at the primary eNB (PCell/eNB). Thus, it has not been feasible to consider relocation of only a subset of a UE's serving cells so far, but CA mobility is assumed to be handled by removing/adding secondary CC(s) in conjunction with Inter PCell handover procedures, i.e. (at first) terminate CA operation temporarily (terminate any secondary carriers/cells) and then, if possible, restart CA and the secondary carriers/cells after the PCell handover was executed.

    [0015] Thus, carrier aggregation is not maintained during inter-site HO, an increased signaling load is involved to terminate/restart the secondary carriers/cells, and it is unsure whether the SCCs/SCells can be reactivated after HO.

    [0016] Thus, there is still a need to further improve such systems in relation to handover in inter-site carrier aggregation scenarios, and hence a need to provide improved devices, methods and computer program products for a corresponding handover procedure for inter-site carrier aggregation scenarios.

    Summary



    [0017] Various aspects of examples of the invention are set out in the claims.

    [0018] According to a first aspect of the present invention, there are provided respective devices as defined in claims 1, 5, and 7.

    [0019] According to a second aspect of the present invention, there are provided respective devices as defined in claims 8, 12, and 14.

    [0020] Advantageous further developments of the respective devices / methods are as set out in respective dependent claims.

    [0021] According to a third aspect of the present invention, there are provided computer program products, as defined in claims 15 to 17, comprising computer-executable components which, when the program is run on a computer, are configured to perform the method aspects as indicated above. The above computer program product/products may be embodied as a computer-readable storage medium.

    [0022] It is thus proposed, according to at least exemplary aspects of the invention, a new procedure and correspondingly configured devices which is/are at least beneficial in regard to the following:
    • an Inter-Site eNB handover/PCell relocation is enabled such that a secondary eNB can remain configured to provide one or more SCells towards the UE (after HO) without interruption;
    • the procedure for PCell Relocation enables to maintain the configuration of serving cells provided by the secondary eNB unaltered, like e.g. shown in the Fig. 1;
    • the procedure supports relocating the "associated macro eNB" (PCell) while a terminal UE has dual-radio connectivity by using LTE and LTE-LAN radio;
    • the procedure/architecture supports a primary eNB to control the resources of a secondary eNB and to pass user-plane data accordingly via a common interface between a primary eNB and Local Area Access Point, the interface representing a backhaul interface supporting X2/S1 like functions;
    • the presented PCell relocation procedure is for example particularly feasible in Inter-Site Carrier Aggregation by using Carrier Aggregation where data flows are split already at Layer Three i.e. in between RLC and PDCP in the LTE radio stack, like for example shown in figure 2;
    • the active backhaul interface can be switched in such scenario to its new route from a secondary/LA BS to a new (target) macro eNB without altering the radio secondary component carrier (CC) connection in between the UE and a secondary base station;
    • the radio handover from the source PCell to the target PCell and the said backhaul-interface path switching is time-organized so that the procedure is seamless without causing packet loss, un-necessary delay or service worsening.

    Brief description of drawings



    [0023] For a more complete understanding of example embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:

    Fig. 1 illustrates a scenario of inter-site carrier aggregation and the entities/interfaces involved prior to (Fig. 1 a) and after (Fig. 1b) handover;

    Fig. 2 illustrates radio-protocol stacks in inter-site carrier aggregation with a flow splitting at Layer 3; and

    Fig. 3 illustrates an example of a signaling for a PCell relocation procedure with carrier aggregation service continuation.


    Description of exemplary embodiments



    [0024] Exemplary aspects / embodiments of the invention will be described herein below.

    [0025] For better understanding of subsequent aspects of the invention, it is noted that in his projects, applicant has already made a couple of associated macro eNB relocation procedure proposals. Those are or were based on an assumption that a handover on the primary radio connection and the macro eNB - LTE-LAN AP backhaul interface path switching for the secondary connection should be executed in two phases, i.e. assuring first that the inter macro eNB (PCell in CA) handover is executed successfully, and only after that perform the said backhaul interface path switching for the "secondary carrier" for possible offloaded or aggregated EPS bearers.

    [0026] This is a quite natural initial thinking as the primary radio connection via the PCell is seen more important to be maintained also in the failure cases, and one easily concludes to make a trade between robustness and overall performance.

    [0027] However, here it should be noted that such two phase procedure does not increase robustness in case an Inter PCell handover failure will occur. This is because the terminal UE may have no possibility to return back to the source PCell/eNB in which radio link quality was fading. Rather, it must perform a new RRC-connection/Service Request procedure to the best received Cell, and previous "old" UE context data become deleted in the source primary eNB (PCell/eNB). Then, after an Inter-eNBl handover failure, the source PCell simply cannot continue serving the former "secondary carrier(s)" and thus the robustness does not become any better by using the proposed two phase solution.

    [0028] In applicant's conceptual work, there is assumed Inter-Site CA, with data split among the sites done within the air-interface protocol stack, and where a fast radio control loop for the secondary carrier component is terminated at the secondary base station. This L3 based multi-radio solution enables less stringent latency requirement in the backhaul between the primary and the secondary base stations in order to support Inter Site CA.

    [0029] The subsequently outlined newly proposed PCell relocation procedure is particularly feasible in the context of Inter Site Carrier Aggregation, where data flow split happens already at Layer Three (L3), i.e. in between RLC and PDCP in the LTE radio stack like shown in figure 2. Though, this is not a pre-requisite for the proper functioning of the example embodiments of the present invention.

    [0030] Fig. 2 shows a master node (serving eNB incl. primary CC), a slave node (secondary eNB incl. secondary CC), and a terminal UE. For substantially each of those nodes, the protocol stack comprises: the packet data convergence protocol, PDCP, at which data are received (for the master node), and below which the data are split prior to being supplied to radio link control, RLC. Below RLC normal LTE MAC-protocol functionality takes place i.e. multiplexing MUX is performed and data are supplied to the hybrid automatic repeat request HARQ stack level, followed by the physical layer PHY, the rafio frequency RF part, which establishes the respective component carriers CC. Control data between master and slave node are exchanged via X2 interface over the X2AP protocol, independent from the shown air-interface protocol stack. Substantially the same applies for the terminal UE, with the exception that downlink data flow through the stack levels is reversed, and e.g. multiplexing is replaced by demultiplexing, and data flow splitting is replaced by data flow combining at layer three, i.e. between RLC and PDCP.

    [0031] In the LTE-LAN and Inter Site CA concepts, it is common that the Serving eNB and the secondary eNB or base station have a backhaul interface supporting X2/S1 like functions in order to let the master node control or at least request for the slave node's resources and to pass user-plane data accordingly.

    [0032] Fig. 1 illustrates a scenario of inter-site carrier aggregation and the entities/interfaces involved prior to (Fig. 1 a) and after (Fig. 1b) handover. Entities or apparatuses involved are as follows for Fig. 1a and 1b.

    [0033] A terminal UE, a source/primary cell eNB such as e.g. a macro eNB #1, a secondary eNB or base station such as e.g. a pico eNB, and a target/primary cell eNB such as a macro eNB #2.

    [0034] The terminal in CA mode has established a primary component carrier PCC towards the serving eNB (eNB#1 before HO, eNB#2 after HO), and at least one secondary component carrier SCC towards secondary eNB or base station. The secondary cell/local access point eNB has a backhaul interface towards each of the (potential) primary cell eNBs. The backhaul interface towards the serving primary eNB is denoted as active backhaul interface. The (potential) primary cell eNBs #1 and #2, respectively, interface each other via an X2 interface.

    [0035] As shown in Fig. 1b, after (and during) HO, the secondary component carrier SCC from the terminal remains the same towards the secondary cell/local access point eNB as before HO. However, the active backhaul interface from the secondary eNB has changed to be the one towards the new serving primary, i.e. target eNB #2, denoted as active backhaul interface in Fig. 1b.

    [0036] The invention is implemented in, at least under an exemplary aspect,
    an apparatus such as an eNB, and comprises a device according to an aspect of the invention. Such device can be a chip or chipset, or a subunit of the apparatus, or the like. The device comprises at least a memory module, MEM, in which software code portions and/or data is stored or are stored. The memory module is connected to a control module ctrl such as a processor, or CPU, or ASIC. The control module is connected to a transceiver module. The transceiver module is configured for communication via the respective RAT and/or frequency band, i.e. configured for the associated service such as LTE, LTE-A with the UE. Such "eNB" may for example be represented by a macro eNB, a pico eNB and/or an LTE-LAN base station (BS).

    [0037] Note that under an implementation aspect of the invention that is software "centric" rather than hardware "centric", respective modules may even be implemented as corresponding functional means (and without departing from the gist of the invention).

    [0038] Note that herein below aspects of the invention are described with a focus on a source eNB (serving primary eNB prior to handover) as well as with a focus on a target eNB (serving primary eNB after handover). This, however, serves to keep the explanation simple. It is to be understood that in practice, each eNB (e.g. macro eNB) may take the role of a source as well as of a target eNB. Thus, it is to be understood that a device such as a eNB comprises/unites both functionalities at a time, as its role may change over time. Moreover, it may take both roles at a time, as an eNB may be a source eNB for a first terminal, e.g. user equipment UE1, but simultaneously may be a target eNB for another terminal, e.g. user equipment UE2.

    [0039] Under a primary eNB/PCell aspect, an eNB represents a device, comprising a control module configured to control a communication module, the communication module being controlled to communicate with a terminal UE in association with at least a first other device (i.e. a secondary eNB), using at least two carriers (PCC and SCC), wherein at least a first carrier (PCC) towards the terminal is established from the device (primary eNB) and at least a second carrier (SCC) is established towards the terminal from the first other device (secondary eNB or base station).

    [0040] Under a target eNB /Pcell aspect, an eNB represent a device, comprising a control module configured to control a communication module, the communication module being controlled to communicate with a terminal UE in association with at least a first other device (i.e. a secondary eNB), using at least two carriers (PCC and SCC), wherein at least a first carrier towards (PCC) towards the terminal is to be established (during HO) from the device, and at least a second carrier (SCC) is established towards the terminal from the first other device (secondary eNB or base station)

    [0041] Under a secondary eNB (or secondary base station) aspect, such an eNB represents a device, comprising a control module configured to control a communication module, the communication module being controlled to communicate with a terminal UE in association with at least another device (source or target primary eNB), using at least two carriers (PCC, SCC), wherein at least a first carrier (PCC) towards the terminal UE is established from the at least one another device (serving or target primary eNB) and at least a second carrier (SCC) is established towards the terminal UE from the device; and an interface towards said another devices, i.e. a backhaul interface to each of a source and target primary eNBs.

    [0042] Now, method aspects in relation to such apparatuses or devices will briefly be outlined below and with reference to Fig. 3. The method can be implemented using computer program products and/or software code portions executed by the control modules of the devices, which when execute perform those method steps.

    [0043] The entities involved and depicted in Fig. 3 are those as explained with reference to Fig. 1 already. Signaling exchanged is illustrated with the horizontal arrows, time/sequence of signaling is reflected by the vertical arrangement of the signals exchanged, and processing performed at a respective entity or apparatus is indicated in "boxes" allocated on the timeline of the respective entity.

    [0044] The following signaling flow diagram in figure 3 illustrates an example implementation of an optimized relocation procedure of a PCell in Inter Site Carrier Aggregation and Local Area offloading, where the ongoing secondary radio path services via the secondary base station will be continued alongside the target primary eNB. The proposed simultaneous data-path handling in LTE-Radio Handover and SCell - PCell backhaul path switching between the secondary and primary base stations provides the best performance and no or at least a shortest possible service break if Inter Site carrier aggregation is used.

    [0045] In order to provide accurate synchronization, the primary eNBs measure and store the average transport delay of the backhaul interface between the secondary and primary base station. This is for example accomplished by using a Ping utility directed to the IP address of the secondary base station(s). (Note that each entity (apparatus or node) in such scenario is identifiable and addressable by an IP (internet Protocol) address associated thereto.)

    [0046] In step 0, there are in advance established an IPSec and SCTP Associations for the SCell - PCell backhaul interfaces, i.e. secondary Base Station is prepared to have backhaul interfaces to multiple primary base stations.

    [0047] In step 1, an evolved packet system connection management, ECM, is set up into connected state.

    [0048] In step 2, the UE is moved to Inter Site Carrier Aggregation mode, i.e. there is a PCell via the primary base station and at least one SCell via the secondary base station.

    [0049] In step 3, UE is sending a measurement report to the primary eNB, with an indication that the primary CC radio connection is fading, which results in that primary eNB makes Inter eNB handover decision. And as a secondary CC is working well, it also decides to continue CA via the target primary eNB.

    [0050] In step 4, a Message 4, Handover Request is used to deliver the required information in order to continue CA operation via the target eNB. For example, such message in step 4 includes secondary BS Identifier, based on which a target eNB is able to verify connectivity and respond accordingly to the source eNB in a subsequent message in a step 5. The message in step 4, for example, optionally also contains UE measurement results of an SCell, based on which the target eNB may verify if the SCell is working well enough in order to continue the CA operation. Now, if the target eNB cannot continue offloading/carrier aggregation, it configures all E-RABs (evolved Radio Access Bearers) into normal LTE single radio mode, and the source eNB issues a resource release request to the secondary base station. The target primary eNB prepares itself to receive the UE in handover and in addition to the current standardized information, it returns in step 5 in a message "Handover Request Ack" the required "target eNB Info", in order to enable the secondary BS to switch its backhaul interface towards the target primary eNB.

    [0051] Upon reception of the message in step 5, the Source primary eNB sends first the message 6' to the secondary base station, and only thereafter then sends the message 6, delayed according to the current measured backhaul delay value, to the UE as an explicit radio handover command (for the UE) to the target PCell.

    [0052] In this handover command, the UE is informed that the SCell configuration specific to the secondary base station remains despite the new PCell (i.e. the RRC is switched to a new eNB, but the User plane remains same through the SCell (s) of the secondary base station).

    [0053] In an example embodiment of this invention, it is encompassed that in addition and prior to the message 6, the Source primary eNB has also sent message 6' in order to command the secondary BS to perform backhaul interface path switching between the primary base stations timely aligned with said radio handover. Among other information, the message 6' contains the mentioned "target eNB Info" which is required for the backhaul interface path switching in uplink direction in the secondary BS.

    [0054] In a message 7, the UE indicates to the target primary eNB the handover/relocation type (i.e. "the PCell relocation while certain SCell configuration remains"). In a similar manner like message 7 indicates successful UE movement to target PCell/eNB, the secondary BS sends message 8 to indicate that a new Backhaul interface between primary and secondary base stationsis to be established. This message 8 contains at least the required information to setup the downlink direction connectivity over the backhaul accordingly.

    [0055] The target primary eNB sends message 9 to the Secondary base station in order to indicate successful relocation procedure.

    [0056] Thereafter, the inter site CA operation can continue via the target PCell/eNB by using new primary CC and intact secondary CC via the secondary base station.

    [0057] The remaining steps of the signaling flow are as usual in the X2 based handover. It should be noted that message 9' may return NAK (negative acknowledgement, Non-ACK) in case UE has not moved to the target PCell/eNB, i.e. a handover failure has happened. In such case, the Secondary base station may release CC resources locally.

    [0058] The present scenario according to Fig. 3 is optimized to full extent, provides lossless packet delivery by using data forwarding in case of acknowledged-mode (AM) bearers, and enables reliable recovery from LTE Handover failure. As a result there is no tradeoff or compromise between performance versus robustness when compared with the basic X2-interface based Inter eNB Handover.

    [0059] Thus, from the above it is understood that according to at least those aspects as outlined above, the present invention proposes an optimized relocation procedure of a primary eNB (PCC) in Inter Site Carrier Aggregation and Local Area offloading, where the ongoing secondary radio path services via the secondary BS will be continued in the target primary eNB, and will not be interrupted during PCC relocation (handover). In this context it is to be noted that the secondary radio link between the UE and secondary BS/eNB remains intact, i.e. only the backhaul interface is switched from SCell to the target PCell/eNB (which will become the new serving cell after HO/relocation).

    [0060] Characteristic to at least an aspect of this relocation procedure is that it timely aligns the execution of the X2 based Inter PCell/eNB Handover and backhaul interface path switching for the secondary connection via the SCell, i.e. these occur synchronized in a single phase, in order to seamlessly continue inter site Carrier Aggregated services in the target PCell/eNB.

    [0061] Also, according to an aspect of the proposed procedure, such relocation procedure includes the Carrier Aggregation related context data transfers over the X2 interface between the source PCell/eNB and the target PCell/eNB, and control signaling over the backhaul interfaces between PCells and the SCell, thus managing the timely aligned sequences. Additionally, according to an aspect, it is proposed to inform in the Radio resource configuration signaling served UE and the target PCell/eNB about the relocation type (i.e. the PCell relocation while SCell configuration remains).

    [0062] In addition to proper timely alignment, an aspect of the present invention also encompasses usage of data forwarding over the "old" backhaul interface between the SCell and the source PCell/eNB, and further over the X2 interface between the Source PCell/eNB and the (new) target PCell/eNB, in order to provide a lossless relocation procedure.

    [0063] Embodiments of the present invention may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware generally reside on a memory module. A memory module may be a volatile or nonvolatile memory module, such as a RAM, ROM, EPROM, EEPROM, or hard disk, or the like. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer or smart phone, or user equipment.

    [0064] The present invention relates in particular but without limitation to mobile communications, for example to environments under LTE, LTE-A, and subsequent releases thereof and can advantageously be implemented in user equipments or smart phones, or personal computers connectable to such networks.

    [0065] That is, it can be implemented as/in chipsets to connected devices, and/or modems thereof. More generally, all products which are subject to a similar environment will see performance improvement with the invention being implemented thereto.

    [0066] If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined.

    [0067] Aspects of the invention as described above encompass an optimised relocation procedure of a PCell/eNB in Inter Site Carrier Aggregation and Local Area offloading, where the ongoing secondary radio path services via the SCell will be continued in the target PCell/eNB. The secondary radio link between the UE and SCell remains intact, i.e. only the backhaul interface is switched from SCell to the target PCell/eNB. Characteristic to this relocation procedure is that it timely aligns the execution of the X2 based Inter PCell/eNB Handover and backhaul interface path switching for the secondary connection via the SCell i.e. these happen synchronized in one (single) phase in order to seamlessly continue inter site Carrier Aggregated services in the target PCell/eNB.

    [0068] In individual aspects thereof, the invention proposes an optimized inter-site CA PCell handover procedure, while keeping the SCell eNB connection active (i.e. the ongoing secondary radio path services via the Scell will be continued in the target PCell/eNB) which comprising transfer the CA context to the target eNB, instruction of the Scell to switch the path to the target Pcell, indication to the UE and target node for the relocation, alignment of the HO sequence for Pcell and Scell. A particular aspect resides in that the Pcell is being subjected to HO first, and then once the UE and target node have received the needed request, the SCell is switched. This involves an optimized timely aligned radio HO and backhaul path switching with related messaging.

    [0069] Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

    [0070] It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

    [0071] The present invention proposes a device, comprising a control module configured to control a communication module, the communication module being controlled to communicate with a terminal in association with at least a first other device, using at least two carriers, wherein at least a first carrier towards the terminal is established from the device and at least a second carrier is established towards the terminal from the first other device; and wherein the control module is configured to receive of a report indicative of a connection quality of the first carrier, responsive thereto a issue a request for handover of the first carrier towards a second device, send a relocation information in relation to the first carrier towards the first other device, and only after sending that relocation information, command the terminal to perform a handover of the first carrier to the second device. Such device, in cooperation with other devices, accomplishes an optimized handover in terms of a primary component carrier relocation from a serving eNB towards a target eNB, while a secondary component carrier is maintained.

    List of exemplary abbreviations/acronyms used:



    [0072] 
    3GPP
    3rd Generation Partnership Project
    AP
    Access Point
    BS
    Base Station
    CA
    Carrier Aggregation
    CC
    Component Carrier
    eNB
    enhanced NodeB
    EPC
    Evolved Packet Core
    EPS
    Evolved Packet System
    EUTRAN
    Evolved UMTS Terrestrial Radio Access Network
    HeNB
    Home enhanced NodeB
    HW
    Hardware
    ID
    Identity
    IP
    Internet Protocol
    IPSec
    IP Security
    LA
    Local Area
    LTE
    Long Term Evolution
    LAE
    Local Area Evolution
    LAN
    Local Area Network
    MME
    Mobility Management Entity
    NB
    NodeB
    PCell
    Primary Cell
    PDCP
    Packet Data Convergence Protocol
    PLMN
    Public Land Mobile Network
    SCell
    Secondary Cell
    UE
    User Equipment
    MS
    Mobile Station
    WLAN
    Wireless Local Area Network
    CATR
    China Academy of Telecommunication Research
    MIIT
    Ministry of Industry and Information Technology (China)
    ERAB
    Evolved Radio Access Bearer



    Claims

    1. A base station in a source primary cell, comprising

    a control module configured to cause the base station in the source primary cell at least to,

    communicate with a terminal associated with at least one other base station in a secondary cell,

    wherein at least a first carrier towards the terminal is established from the base station in the source primary cell and at least a second carrier is established towards the terminal from the at least one other base station in the secondary cell;

    receive from the terminal, a report indicative of a connection quality of the first carrier;

    responsive thereto, issue to a base station in a target primary cell, a request for handover of the first carrier towards the base station in the target primary cell;

    send towards the at least one other base station in the secondary cell, a relocation information in relation to the first carrier; and

    command the terminal to perform a handover of the first carrier to the base station in the target primary cell.


     
    2. A base station in a source primary cell according to claim 1, further comprising

    an interface towards said at least one other base station in the secondary cell,

    a measurement module configured to measure an average transport delay for data that are exchanged between the base station in the source primary cell and said at least one other base station in the secondary cell via said interface, wherein

    the control module is configured to

    delay the command to the terminal after sending the relocation information according to the measured transport delay.


     
    3. A base station in a source primary cell according to claim 2, wherein

    the measurement module is configured to measure the transport delay based on a Ping procedure directed to an address of a respective other base station in the secondary cell.


     
    4. A base station in a source primary cell according to claim 1, wherein
    the control module is configured to

    include, in said request for handover, information indicative of the first carrier established towards the terminal from the base station in the source primary cell and of the at least second carrier established towards the terminal from the at least one other base station in the secondary cell.


     
    5. A base station in a target primary cell, comprising

    a control module configured to cause the base station in the target primary cell at least to,

    communicate with a terminal associated with at least one other base station in a secondary cell,

    wherein at least a first carrier towards the terminal is to be established from the base station in the target primary cell and at least a second carrier is established towards the terminal from the at least one other base station in a secondary cell;

    receive from a base station in a source primary cell, a request for handover of the first carrier from the base station in the source primary cell to the base station in the target primary cell;

    determine, responsive thereto, that the base station in the target primary cell has connectivity to the at least one other base station in the secondary cell, and

    acknowledge to the base station in the source primary cell, the determined connectivity together with the identification information of the base station in the target primary cell.


     
    6. A base station in a target primary cell according to claim 5, further comprising

    an interface towards said at least one other base station in the secondary cell, and

    wherein said request for handover includes an identifier of the one other base station in the secondary cell, and

    the control module is configured to determine that the base station in the target primary cell has connectivity via the interface to the at least one other base station in the secondary cell based on the identifier.


     
    7. A base station in a secondary cell, comprising

    a first interface towards a base station in a source primary cell and a second interface towards a base station in a target primary cell; and

    a control module configured to cause the base station in the secondary cell at least to,

    communicate with a terminal associated with a base station in a source or target primary cell,

    wherein at least a first carrier towards the terminal is established from the base station in the source primary cell and at least a second carrier is established towards the terminal from the base station in the secondary cell;

    receive relocation information in relation to the first carrier to be relocated towards the base station in the target primary cell, and

    switch, responsive thereto, secondary cell-primary cell backhaul path from the first interface to the second interface.


     
    8. A method, comprising

    in a base station in a source primary cell,

    communicating with a terminal associated with at least one other base station in a secondary cell, wherein at least a first carrier towards the terminal is established from the base station in the source primary cell and at least a second carrier is established towards the terminal from the at least one other base station in the secondary cell;

    receiving from the terminal, a report indicative of a connection quality of the first carrier;

    responsive thereto, issuing to a base station in a target primary cell, a request for handover of the first carrier towards the base station in the target primary cell;

    sending towards the at least one other base station in the secondary cell, a relocation information in relation to the first carrier; and

    commanding the terminal to perform a handover of the first carrier to the base station in the target primary cell.


     
    9. A method according to claim 8, further comprising

    providing for an interface from the base station in the source primary cell towards said at least one other base station in the secondary cell,

    measuring an average transport delay for data that are exchanged between the base station in the source primary cell and said at least one other base station in the secondary cell via said interface, and

    delaying the commanding the terminal after sending the relocation information according to the measured transport delay.


     
    10. A method according to claim 9, wherein

    measuring the transport delay is based on a Ping procedure directed to an address of a respective other base station in the secondary cell.


     
    11. A method according to claim 8, further comprising

    including, in said request for handover, information indicative of the first carrier established towards the terminal and of the at least second carrier established towards the terminal from the at least one other base station in the secondary cell.


     
    12. A method, comprising
    in a base station in a target primary cell,

    communicating with a terminal associated with at least one other base station in a secondary cell, wherein at least a first carrier towards the terminal is to be established from the base station in the target primary cell and at least a second carrier is established towards the terminal from the at least one other base station in the secondary cell;

    receiving from a base station in a source primary cell, a request for handover of the first carrier from the base station in the source primary cell to the base station in the target primary cell;

    determining, responsive thereto, that the base station in the target primary cell has connectivity to the at least one other base station in the secondary cell, and

    acknowledging to the base station in the source primary cell, the determined connectivity together with the identification information of the base station in the target primary cell.


     
    13. A method according to claim 12, further comprising

    providing for an interface from the base station in the target primary cell towards said at least one other base station in the secondary cell, and

    wherein said request for handover includes an identifier of the at least one other base station in the secondary cell, and

    determining that the base station in the target primary cell has connectivity via the interface to the at least one other base station in the secondary cell based on the identifier.


     
    14. A method, comprising
    in a base station in a secondary cell,

    communicating with a terminal associated with a base station in a source or target primary cell, wherein at least a first carrier towards the terminal is established from the base station in the source primary cell and at least a second carrier is established towards the terminal from the base station in the secondary cell;

    providing a first interface towards the base station in the source primary cell and a second interface towards to the base station in the target primary cell, and

    receiving from said base station in the source primary cell, relocation information in relation to the first carrier to be relocated towards the base station in the target primary cell, and

    switching, responsive thereto, secondary cell-primary cell backhaul path from the first interface to the second interface.


     
    15. A computer program product comprising computer-executable components which, when the program is run on a computer, are configured to perform the method steps according to any of claims 8 to 11.
     
    16. A computer program product comprising computer-executable components which, when the program is run on a computer, are configured to perform the method steps according to any of claims 12 to 13.
     
    17. A computer program product comprising computer-executable components which, when the program is run on a computer, are configured to perform the method steps according to claim 14.
     


    Ansprüche

    1. Basisstation in einer Quellen-Primärzelle, umfassend:

    ein Steuermodul, das dafür ausgelegt ist, die Basisstation in der Quellen-Primärzelle zu mindestens Folgendem zu veranlassen:

    Kommunizieren mit einem Endgerät, das mindestens einer anderen Basisstation in einer Sekundärzelle zugeordnet ist,

    wobei mindestens ein erster Träger in Richtung des Endgeräts von der Basisstation in der Quellen-Primärzelle hergestellt wird und mindestens ein zweiter Träger in Richtung des Endgeräts von der mindestens einen anderen Basisstation in der Sekundärzelle hergestellt wird;

    Empfangen einer Meldung von dem Endgerät, die eine Verbindungsqualität des ersten Trägers angibt;

    als Reaktion darauf Ausgeben, an eine Basisstation in einer Ziel-Primärzelle, einer Anforderung der Weiterreichung des ersten Trägers in Richtung der Basisstation in der Ziel-Primärzelle;

    Senden einer Versetzungsinformation in Beziehung auf den ersten Träger in Richtung der mindestens einen anderen Basisstation in der Sekundärzelle; und

    Anweisen des Endgeräts, eine Weiterreichung des ersten Trägers an die Basisstation in der Ziel-Primärzelle durchzuführen.


     
    2. Basisstation in einer Quellen-Primärzelle nach Anspruch 1, ferner umfassend:

    eine Schnittstelle in Richtung der mindestens einen anderen Basisstation in der Sekundärzelle,

    ein Messmodul, ausgelegt zum Messen einer mittleren Transportverzögerung für Daten, die zwischen der Basisstation in der Quellen-Primärzelle und der mindestens einen anderen Basisstation in der Sekundärzelle über die Schnittstelle ausgetauscht werden, wobei

    das Steuermodul ausgelegt ist zum
    Verzögern der Anweisung an das Endgerät nach dem Senden der Versetzungsinformation gemäß der gemessenen Transportverzögerung.


     
    3. Basisstation in einer Quellen-Primärzelle nach Anspruch 2, wobei
    das Messmodul ausgelegt ist zum Messen der Transportverzögerung auf der Basis einer Ping-Prozedur, die an eine Adresse einer jeweiligen anderen Basisstation in der Sekundärzelle gerichtet ist.
     
    4. Basisstation in einer Quellen-Primärzelle nach Anspruch 1, wobei
    das Steuermodul ausgelegt ist zum
    Aufnehmen von Informationen in die Anforderung der Weiterreichung, die den ersten Träger, der in Richtung des Endgeräts von der Basisstation in der Quellen-Primärzelle hergestellt wird, und den mindestens einen zweiten Träger, der in Richtung des Endgeräts von der mindestens einen anderen Basisstation in der Sekundärzelle hergestellt wird, angeben.
     
    5. Basisstation in einer Ziel-Primärzelle, umfassend:

    ein Steuermodul, das dafür ausgelegt ist, die Basisstation in der Ziel-Primärzelle zu mindestens Folgendem zu veranlassen:

    Kommunizieren mit einem Endgerät, das mindestens einer anderen Basisstation in einer Sekundärzelle zugeordnet ist,

    wobei mindestens ein erster Träger in Richtung des Endgeräts von der Basisstation in der Quellen-Primärzelle hergestellt wird und mindestens ein zweiter Träger in Richtung des Endgeräts von der mindestens einen anderen Basisstation in einer Sekundärzelle hergestellt wird;

    Empfangen, von einer Basisstation in einer Quellen-Primärzelle, einer Anforderung der Weiterreichung des ersten Trägers von der Basisstation in der Quellen-Primärzelle an die Basisstation in der Ziel-Primärzelle;

    als Reaktion darauf Bestimmen, dass die Basisstation in der Ziel-Primärzelle Konnektivität mit mindestens einer anderen Basisstation in der Sekundärzelle aufweist, und

    der Basisstation in der Quellen-Primärzelle die bestimmte Konnektivität zusammen mit den Identifikationsinformationen der Basisstation in der Ziel-Primärzelle bestätigen.


     
    6. Basisstation in einer Ziel-Primärzelle nach Anspruch 5, ferner umfassend:

    eine Schnittstelle in Richtung mindestens einer anderen Basisstation in der Sekundärzelle und

    wobei die Anforderung der Weiterreichung eine Kennung der einen anderen Basisstation in der Sekundärzelle umfasst und

    das Steuermodul ausgelegt ist zum Bestimmen, dass die Basisstation in der Ziel-Primärzelle Konnektivität über die Schnittstelle zu der mindestens einen anderen Basisstation in der Sekundärzelle hat, auf der Basis der Kennung.


     
    7. Basisstation in einer Sekundärzelle, umfassend:

    eine erste Schnittstelle in Richtung einer Basisstation in einer Quellen-Primärzelle und eine zweite Schnittstelle in Richtung einer Basisstation in einer Ziel-Primärzelle; und

    ein Steuermodul, das dafür ausgelegt ist, die Basisstation in der Sekundärzelle zu mindestens Folgendem zu veranlassen:

    Kommunizieren mit einem Endgerät, das einer Basisstation in einer Quellen- oder Ziel-Primärzelle zugeordnet ist,

    wobei mindestens ein erster Träger in Richtung des Endgeräts von der Basisstation in der Quellen-Primärzelle hergestellt wird und mindestens ein zweiter Träger in Richtung des Endgeräts von der Basisstation in der Sekundärzelle hergestellt wird;

    Empfangen von Versetzungsinformationen in Bezug auf den ersten Träger, der in Richtung der Basisstation in der Ziel-Primärzelle versetzt werden soll, und

    als Reaktion darauf Wechseln des Sekundärzellen-Primärzellen-Backhaul-Pfads von der ersten Schnittstelle auf die zweite Schnittstelle.


     
    8. Verfahren, das in einer Basisstation in einer Quellen-Primärzelle Folgendes umfasst:

    Kommunizieren mit einem Endgerät, das mindestens einer anderen Basisstation in einer Sekundärzelle zugeordnet ist, wobei mindestens ein erster Träger in Richtung des Endgeräts von der Basisstation in der Quellen-Primärzelle hergestellt wird und mindestens ein zweiter Träger in Richtung des Endgeräts von der mindestens einen anderen Basisstation in der Sekundärzelle hergestellt wird;

    Empfangen einer Meldung von dem Endgerät, die eine Verbindungsqualität des ersten Trägers angibt;

    als Reaktion darauf Ausgeben, an eine Basisstation in einer Ziel-Primärzelle, einer Anforderung der Weiterreichung des ersten. Trägers in Richtung der Basisstation in der Ziel-Primärzelle;

    Senden einer Versetzungsinformation in Bezug auf den ersten Träger in Richtung der mindestens einen anderen Basisstation in der Sekundärzelle; und

    Anweisen des Endgeräts, eine Weiterreichung des ersten Trägers an die Basisstation in der Ziel-Primärzelle durchzuführen.


     
    9. Verfahren nach Anspruch 8, ferner umfassend:

    Bereitstellen einer Schnittstelle von der Basisstation in der Quellen-Primärzelle in Richtung der mindestens einen anderen Basisstation in der Sekundärzelle,

    Messen einer mittleren Transportverzögerung für Daten, die zwischen der Basisstation in der Quellen-Primärzelle und der mindestens einen anderen Basisstation in der Sekundärzelle über die Schnittstelle ausgetauscht werden, und

    Verzögern des Anweisens des Endgeräts nach dem Senden der Versetzungsinformation gemäß der gemessenen Transportverzögerung.


     
    10. Verfahren nach Anspruch 9, wobei
    Messen der Transportverzögerung auf einer Ping-Prozedur basiert, die an eine Adresse einer jeweiligen anderen Basisstation in der Sekundärzelle gerichtet ist.
     
    11. Verfahren nach Anspruch 8, ferner umfassend:

    Aufnehmen von Informationen in die Anforderung der Weiterreichung, die den ersten Träger, der in Richtung des Endgeräts hergestellt wird, und den mindestens einen zweiten Träger, der in Richtung des Endgeräts von der mindestens einen anderen Basisstation in der Sekundärzelle hergestellt wird, angeben.


     
    12. Verfahren, das in einer Basisstation in einer Ziel-Primärzelle Folgendes umfasst:

    Kommunizieren mit einem Endgerät, das mindestens einer anderen Basisstation in einer Sekundärzelle zugeordnet ist, wobei mindestens ein erster Träger in Richtung des Endgeräts von der Basisstation in der Ziel-Primärzelle herzustellen ist und mindestens ein zweiter Träger in Richtung des Endgeräts von der mindestens einen anderen Basisstation in der Sekundärzelle hergestellt wird;

    Empfangen, von einer Basisstation in einer Quellen-Primärzelle, einer Anforderung der Weiterreichung des ersten Trägers von der Basisstation in der Quellen-Primärzelle an die Basisstation in der Ziel-Primärzelle;

    als Reaktion darauf Bestimmen, dass die Basisstation in der Ziel-Primärzelle Konnektivität zu der mindestens einen anderen Basisstation in der Sekundärzelle hat, und

    der Basisstation in der Quellen-Primärzelle die bestimmte Konnektivität zusammen mit den Identifikationsinformationen der Basisstation in der Ziel-Primärzelle bestätigen.


     
    13. Verfahren nach Anspruch 12, ferner umfassend:

    Bereitstellen einer Schnittstelle von der Basisstation in der Ziel-Primärzelle in Richtung der mindestens einen anderen Basisstation in der Sekundärzelle und

    wobei die Anforderung der Weiterreichung eine Kennung der mindestens einen anderen Basisstation in der Sekundärzelle umfasst und

    Bestimmen, dass die Basisstation in der Ziel-Primärzelle Konnektivität über die Schnittstelle zu der mindestens einen anderen Basisstation in der Sekundärzelle hat, auf der Basis der Kennung.


     
    14. Verfahren, das in einer Basisstation in einer Sekundärzelle Folgendes umfasst:

    Kommunizieren mit einem Endgerät, das einer Basisstation in einer Quellen- oder Ziel-Primärzelle zugeordnet ist, wobei mindestens ein erster Träger in Richtung des Endgeräts von der Basisstation in der Quellen-Primärzelle hergestellt wird und mindestens ein zweiter Träger in Richtung des Endgeräts von der Basisstation in der Sekundärzelle hergestellt wird;

    Bereitstellen einer ersten Schnittstelle in Richtung der Basisstation in der Quellen-Primärzelle und einer zweiten Schnittstelle in Richtung der Basisstation in der Ziel-Primärzelle und

    Empfangen, von der Basisstation in der Quellen-Primärzelle, von Versetzungsinformationen in Bezug auf den ersten Träger, der in Richtung der Basisstation in der Ziel-Primärzelle zu versetzen ist, und

    als Reaktion darauf Wechseln des Sekundär-Zellenprimär-Zellen-Backhaul-Pfads von der ersten Schnittstelle auf die zweite Schnittstelle.


     
    15. Computerprogrammprodukt mit computerausführbaren Komponenten, die, wenn das Programm auf einem Computer ausgeführt wird, ausgelegt sind zum Ausführen der Verfahrensschritte nach einem der Ansprüche 8 bis 11.
     
    16. Computerprogrammprodukt mit computerausführbaren Komponenten, die, wenn das Programm auf einem Computer ausgeführt wird, ausgelegt sind zum Ausführen der Verfahrensschritte nach einem der Ansprüche 12 bis 13.
     
    17. Computerprogrammprodukt mit computerausführbaren Komponenten, die, wenn das Programm auf einem Computer ausgeführt wird, ausgelegt sind zum Ausführen der Verfahrensschritte nach Anspruch 14.
     


    Revendications

    1. Station de base dans une cellule primaire source, comprenant :

    un module de commande configuré pour amener la station de base dans la cellule primaire source au moins à :

    une communication avec un terminal associé à au moins une autre station de base dans une cellule secondaire,

    au moins une première porteuse vers le terminal étant établie à partir de la station de base dans la cellule primaire source et au moins une deuxième porteuse étant établie vers le terminal à partir de ladite autre station de base dans la cellule secondaire ;

    la réception, à partir du terminal, d'un rapport indiquant une qualité de connexion de la première porteuse ;

    en réponse à ce dernier, l'émission à une station de base dans une cellule primaire cible, d'une requête de transfert intercellulaire de la première porteuse vers la station de base dans la cellule primaire cible ;

    l'envoi à ladite autre station de base dans la cellule secondaire, d'informations de relocalisation relativement à la première porteuse ; et

    la commande d'exécution d'un transfert intercellulaire de la première porteuse vers la station de base dans la cellule primaire cible, au terminal.


     
    2. Station de base dans une cellule primaire source selon la revendication 1, comprenant en outre :

    une interface avec ladite autre station de base dans la cellule secondaire,

    un module de mesure configuré pour mesurer un retard de transport moyen pour des données qui sont échangées entre la station de base dans la cellule primaire source et ladite autre station de base dans la cellule secondaire par le biais de ladite interface,

    le module de commande étant configuré pour

    retarder la commande faite au terminal après l'envoi des informations de relocalisation selon le retard de transport mesuré.


     
    3. Station de base dans une cellule primaire source selon la revendication 2, dans laquelle :

    le module de mesure est configuré pour mesurer le retard de transport sur la base d'une procédure Ping adressée à une autre station de base respective dans la cellule secondaire.


     
    4. Station de base dans une cellule primaire source selon la revendication 1, dans laquelle :

    le module de commande est configuré pour

    l'inclusion, dans ladite requête de transfert intercellulaire, d'informations indiquant la première porteuse établie vers le terminal à partir de la station de base dans la cellule primaire source et ladite deuxième porteuse établie vers le terminal à partir de ladite autre station de base dans la cellule secondaire


     
    5. Station de base dans une cellule primaire cible, comprenant :

    un module de commande configuré pour amener la station de base dans la cellule primaire cible au moins à :

    une communication avec un terminal associé à au moins une autre station de base dans une cellule secondaire,

    au moins une première porteuse vers le terminal devant être établie à partir de la station de base dans la cellule primaire cible et au moins une deuxième porteuse étant établie vers le terminal à partir de ladite autre station de base dans une cellule secondaire ;

    la réception, à partir d'une station de base dans une cellule primaire source, d'une requête de transfert intercellulaire de la première porteuse depuis la station de base dans la cellule primaire source vers la station de base dans la cellule primaire cible ;

    la détermination, en réponse à cette dernière, que la station de base dans la cellule primaire cible a une connectivité avec ladite autre station de base dans la cellule secondaire, et

    un accusé de réception envoyé à la station de base dans la cellule primaire source, de la connectivité déterminée conjointement avec les informations d'identification de la station de base dans la cellule primaire cible.


     
    6. Station de base dans une cellule primaire cible selon la revendication 5, comprenant en outre :

    une interface avec ladite autre station de base dans la cellule secondaire, et

    ladite requête de transfert intercellulaire comportant un identifiant de la une autre station de base dans la cellule secondaire, et

    le module de commande étant configuré pour déterminer que la station de base dans la cellule primaire cible a une connectivité par le biais de l'interface avec ladite autre station de base dans la cellule secondaire sur la base de l'identifiant.


     
    7. Station de base dans une cellule secondaire, comprenant :

    une première interface avec une station de base dans une cellule primaire source et une deuxième interface avec une station de base dans une cellule primaire cible ; et

    un module de commande configuré pour amener la station de base dans la cellule secondaire au moins à :

    une communication avec un terminal associé à une station de base dans une cellule primaire source ou cible,

    au moins une première porteuse vers le terminal étant établie à partir de la station de base dans la cellule primaire source et au moins une deuxième porteuse étant établie vers le terminal à partir de la station de base dans la cellule secondaire ;

    la réception d'informations de relocalisation relativement à la première porteuse devant être relocalisée vers la station de base dans la cellule primaire cible, et

    la commutation, en réponse à ces dernières, d'un chemin de liaison cellule secondaire - cellule primaire depuis la première interface vers la deuxième interface.


     
    8. Procédé, comprenant :

    dans une station de base dans une cellule primaire source,

    une communication avec un terminal associé à au moins une autre station de base dans une cellule secondaire, au moins une première porteuse vers le terminal étant établie à partir de la station de base dans la cellule primaire source et au moins une deuxième porteuse étant établie vers le terminal à partir de ladite autre station de base dans la cellule secondaire ;

    la réception, à partir du terminal, d'un rapport indiquant une qualité de connexion de la première porteuse ;

    en réponse à ce dernier, l'émission à une station de base dans une cellule primaire cible, d'une requête de transfert intercellulaire de la première porteuse vers la station de base dans la cellule primaire cible ;

    l'envoi à ladite autre station de base dans la cellule secondaire, d'informations de relocalisation relativement à la première porteuse ; et

    la commande d'exécution d'un transfert intercellulaire de la première porteuse vers la station de base dans la cellule primaire cible, au terminal.


     
    9. Procédé selon la revendication 8, comprenant en outre :

    la fourniture d'une interface depuis la station de base dans la cellule primaire source vers ladite autre station de base dans la cellule secondaire,

    la mesure d'un retard de transport moyen pour des données qui sont échangées entre la station de base dans la cellule primaire source et ladite autre station de base dans la cellule secondaire par le biais de ladite interface, et

    le retard de la commande faite au terminal après l'envoi des informations de relocalisation selon le retard de transport mesuré.


     
    10. Procédé selon la revendication 9, dans lequel :

    l'étape de mesure du retard de transport est basée sur une procédure Ping adressée à une autre station de base respective dans la cellule secondaire.


     
    11. Procédé selon la revendication 8, comprenant en outre :

    l'inclusion, dans ladite requête de transfert intercellulaire, d'informations indiquant la première porteuse établie vers le terminal et ladite deuxième porteuse établie vers le terminal à partir de ladite autre station de base dans la cellule secondaire.


     
    12. Procédé, comprenant :

    dans une station de base dans une cellule primaire cible,

    une communication avec un terminal associé à au moins une autre station de base dans une cellule secondaire, au moins une première porteuse vers le terminal devant être établie à partir de la station de base dans la cellule primaire cible et au moins une deuxième porteuse étant établie vers le terminal à partir de ladite autre station de base dans la cellule secondaire ;

    la réception, à partir d'une station de base dans une cellule primaire source, d'une requête de transfert intercellulaire de la première porteuse depuis la station de base dans la cellule primaire source vers la station de base dans la cellule primaire cible ;

    la détermination, en réponse à cette dernière, que la station de base dans la cellule primaire cible a une connectivité avec ladite autre station de base dans la cellule secondaire, et

    un accusé de réception envoyé à la station de base dans la cellule primaire source, de la connectivité déterminée conjointement avec les informations d'identification de la station de base dans la cellule primaire cible.


     
    13. Procédé selon la revendication 12, comprenant en outre :

    la fourniture d'une interface depuis la station de base dans la cellule primaire cible vers ladite autre station de base dans la cellule secondaire, et

    ladite requête de transfert intercellulaire comportant un identifiant de ladite autre station de base dans la cellule secondaire, et

    la détermination que la station de base dans la cellule primaire cible a une connectivité par le biais de l'interface avec ladite autre station de base dans la cellule secondaire sur la base de l'identifiant.


     
    14. Procédé, comprenant :

    dans une station de base dans une cellule secondaire,

    une communication avec un terminal associé à une station de base dans une cellule primaire source ou cible, au moins une première porteuse vers le terminal étant établie à partir de la station de base dans la cellule primaire source et au moins une deuxième porteuse étant établie vers le terminal à partir de la station de base dans la cellule secondaire ;

    la fourniture d'une première interface vers la station de base dans la cellule primaire source et d'une deuxième interface vers la station de base dans la cellule primaire cible, et

    la réception à partir de ladite station de base dans la cellule primaire source, d'informations de relocalisation relativement à la première porteuse devant être relocalisée vers la station de base dans la cellule primaire cible, et

    la commutation, en réponse à ces dernières, d'un chemin de liaison cellule secondaire - cellule primaire depuis la première interface vers la deuxième interface.


     
    15. Produit programme d'ordinateur comprenant des composants exécutables par ordinateur qui, lorsque le programme est exécuté sur un ordinateur, sont configurés pour mettre en oeuvre les étapes de procédé selon l'une quelconque des revendications 8 à 11.
     
    16. Produit programme d'ordinateur comprenant des composants exécutables par ordinateur qui, lorsque le programme est exécuté sur un ordinateur, sont configurés pour mettre en oeuvre les étapes de procédé selon l'une quelconque des revendications 12 à 13.
     
    17. Produit programme d'ordinateur comprenant des composants exécutables par ordinateur qui, lorsque le programme est exécuté sur un ordinateur, sont configurés pour mettre en oeuvre les étapes de procédé selon la revendication 14.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description