Patent Description:
Currently, in a wireless communication system, technology of carrying out wireless data connections with a plurality of base stations over different carriers simultaneously by user equipment has been widely discussed. However, a solution under specific scenes has not been launched.

<CIT> and <CIT> disclose handover of a user equipment from a source node to a target node.

The invention is disclosed by the appended claims.

The disclosure can be better understood with reference to the detailed description given below in conjunction with the accompanying drawings, throughout which identical or like reference signs denote identical or like components. The accompanying drawings together with the following detailed description are incorporated into and form a part of the specification and serve to further illustrate the preferred embodiments of the disclosure and to explain the principle and advantages of the disclosure by way of example. In the drawings:.

Exemplary embodiments of the present disclosure will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all the features of practical implementations are described in the specification. However, it is to be appreciated that numerous implementation-specific decisions shall be made during developing any of such practical implementations so as to achieve the developer's specific goals, for example, to comply with system- and service-related constraining conditions which will vary from one implementation to another. Moreover, it shall also be appreciated that such a development effort might be very complex and time-consuming but may simply be a routine task for those skilled in the art benefiting from this disclosure.

It shall further be noted that only those device structures and/or process steps closely relevant to the solutions of the disclosure are illustrated in the drawings while other details less relevant to the disclosure are omitted so as not to obscure the disclosure due to those unnecessary details.

Embodiments of the disclosure will be described with reference to <FIG> below. First, an example of a wireless communication system according to an embodiment of the disclosure will be described with reference to <FIG> is a schematic block diagram illustrating a wireless communication system according to an embodiment of the disclosure.

As shown in <FIG>, the wireless communication system <NUM> according to the embodiment of the disclosure may include a first base station <NUM>, a second base station <NUM>, a third base station <NUM> and user equipment <NUM>. Particularly, the first base station <NUM> and the second base station <NUM> perform wireless data connection with the user equipment <NUM> over different carriers, and a triggering node triggers a transfer procedure if it judges a predetermined transfer condition for transferring services provided to the user equipment <NUM> by the second base station <NUM> to the third base station <NUM> is satisfied, so that the user equipment <NUM> releases wireless data connection with the second base station <NUM> and establishes wireless data connection with the third base station <NUM>, and thus the first base station <NUM> and the third base station <NUM> perform wireless data connection with the user equipment <NUM> over different carriers, and at least part of the services originally provided by the second base station <NUM> is transferred to the third base station <NUM>.

The predetermined transfer condition under which the services provided to the user equipment <NUM> by the second base station <NUM> is transferred to the third base station <NUM> includes one or more of the following factors: service quality of the third base station <NUM> is higher than service quality of the second base station <NUM> by a predetermined threshold; the service quality of the third base station <NUM> is higher than a predetermined threshold; the service quality of the second base station <NUM> is lower than a first predetermined threshold and the service quality of the third base station <NUM> is higher than a second predetermined threshold; and so on. It is to be understood that the above predetermined transfer condition has been described assuming that an object to be transferred has been determined among the first base station <NUM> and the second base station <NUM>.

On the other hand, when both base stations which perform wireless data connection with the user equipment over different carriers satisfy the predetermined transfer condition at the same time, in a case that it has not been determined which base station is to be transferred first (that is, during a two-step transfer procedure, which base station is the first base station <NUM>, which base station is the second base station <NUM> and which base station is the third base station <NUM>), as an alternative example, the above described predetermined transfer condition may further include for example the service quality of one base station is higher than that of another base station.

Preferably, when determining the object to be transferred among the above two base stations, measurement results regarding serving carriers of these two base stations should be reported to the triggering node, then the triggering node will determine the transfer procedure with respect to which base station is to be started first based on a type of the base station (for example, master node/slave node, macro base station/low power node, and the like), channel quality or load condition or the like. As an alternative example, if the channel quality of one base station is lower than a predetermined threshold and approximates failure while another base station is looking for a better neighbor, then a base station with poorest channel quality is determined as the object to be transferred, and the transfer procedure with respect to this base station is started first. As another alternative example, if two base stations have substantially the same channel quality, then a base station with heavier load will be determined as the object to be transferred, and the transfer procedure with respect to this base station is started first.

Further, preferably, in a case that all of the services originally provided by the second base station <NUM> can not be transferred to the third base station <NUM>, the transfer procedure further causes part of the services originally provided by the second base station <NUM> to be transferred to the first base station <NUM>. It is to be noted that although <FIG> shows only one first base station <NUM>, the number of the first base station <NUM> is not limited thereto, and the first base station <NUM> may be a set of base stations including a plurality of first base stations, for example, a plurality of coordinated base stations in Joint Processing technology, and thus during the above transfer procedure, part of the services originally provided by the second base station <NUM> may be transferred to one or more first base stations in the set of base stations. Further, in this case, the service quality of the plurality of first base stations is measured in a cell unit, for example, in case of Coordinated Multiple Point (CoMP) transmission, the service quality of multiple coordinated base stations may be measured by regarding a carrier coordinated by the multiple base stations as one cell.

Further, it is to be understood that during the above transfer procedure, the first base station <NUM> always maintains the wireless data connection with the user equipment, the services provided by the second base station <NUM> is transferred, and at least part of the services originally provided by the second base station <NUM> is transferred to the third base station <NUM>, and thus in some embodiments of the invention, the first base station <NUM> may be also referred to as a connection maintaining node, the second base station <NUM> may be also referred to as a connection transfer source node, and the third base station <NUM> may be also referred to as a connection transfer target node. The above described triggering node may be one serving node to which the user equipment <NUM> is connected currently, for example, may be the first base station <NUM> as the connection maintaining node, and may be also the second base station <NUM> as the connection transfer source node.

Further, it is to be understood that the terms "first", "second" and "third" used herein are only used for distinguishing to facilitate description but not limitation, for example, when the first base station <NUM> conforms to characteristics of the connection transfer source node or the connection transfer target node, the first base station <NUM> can of course be the connection transfer source node or the connection transfer target node, and this also applies to the second base station <NUM> and the third base station <NUM>.

Specifically, in a case that the triggering node judges the predetermined transfer condition is satisfied according to mobility measurement result regarding serving carriers of at least the second base station <NUM> and optionally the first base station <NUM> and the third base station <NUM>, the triggering node sends a transfer request containing relevant information of the first base station and the second base station to the third base station <NUM>, and the third base station <NUM> performs a first admission control according to the transfer request and sends a transfer response to notify a result of the first admission control. Particularly, the third base station <NUM> may return the transfer response directly to the triggering node, or may send the transfer response to another serving node connected with the user equipment <NUM>.

Preferably, the transfer response may include for which part of radio bearer of the user equipment <NUM> that the third base station <NUM> can perform communication, a dedicated preamble code as required when making synchronized access to the third base station <NUM>, system information about a carrier for communication between the user equipment <NUM> and the third base station <NUM> and configuration information about a control plane protocol for establishing communication between the user equipment <NUM> and the third base station <NUM>.

Preferably, if the result of the first admission control indicates that the third base station <NUM> can not accept all the radio bearers between the user equipment <NUM> and the second base station <NUM>, then according to the transfer response of the third base station <NUM> (the transfer response directly received from the third base station <NUM> or the transfer response of the third base station <NUM> forwarded to the first base station <NUM> via the second base station <NUM>), the first base station <NUM> performs a second admission control according to the result of the first admission control and notifies a result of the second admission control to the second base station <NUM>.

Further, preferably, the first base station <NUM> or the second base station <NUM> sends, after acquiring the final result of the first admission control or the second admission control, a notification message to the user equipment <NUM> to notify the user equipment <NUM> to perform the transfer procedure according to the final result and the transfer response of the third base station <NUM>. The notification message includes at least one of: for which part of radio bearer of the user equipment that the first base station <NUM> can perform communication, for which part of radio bearer of the user equipment <NUM> that the third base station <NUM> can perform communication, a dedicated preamble code as required when making synchronized access to the third base station <NUM>, system information about a carrier for communication between the user equipment <NUM> and the third base station <NUM> and configuration information about a control plane protocol for establishing communication between the user equipment <NUM> and the third base station <NUM>. Also, the user equipment <NUM> releases radio bearers which can not be accepted by the first base station <NUM> and the third base station <NUM> after receiving the notification message, releases the wireless data connection with the second base station <NUM> and performs synchronized access operation to the third base station <NUM>.

Further, preferably, the above described triggering node may be the first base station <NUM> or the second base station <NUM>.

Examples of scenes of the transfer procedure in cases that the first base station <NUM> and the second base station <NUM> serve as the triggering node respectively will be described with reference to <FIG> below. <FIG> is a schematic diagram illustrating an exemplary scene in which the first base station serves as the triggering node to trigger the transfer procedure according to an embodiment of the disclosure, and <FIG> is a schematic diagram illustrating an exemplary scene in which the second base station serves as the triggering node to trigger the transfer procedure according to an embodiment of the disclosure.

As shown in <FIG>, in a case that the first base station <NUM> serves as the triggering node, the user equipment <NUM> may send the mobility measurement result to the second base station <NUM>, and the second base station <NUM> forwards the mobility measurement result to the first base station <NUM> as shown by solid-line arrows in <FIG> as reference for the first base station <NUM> to trigger the transfer procedure. An advantage of this example lies in reducing modifications to the existing standard (the user equipment directly reports to a serving base station the mobility carrier measurement result of the serving base station). Further, the user equipment <NUM> may also send the mobility measurement result regarding a serving carrier (containing at least a primary carrier) of the second base station <NUM> to the first base station <NUM> in "measurement report" for example, as shown by a broken-line arrow in <FIG>. An advantage of this example lies in that the user equipment <NUM> may directly send the measurement report regarding the serving carrier of the second base station <NUM> to the first base station <NUM>, thereby saving information interaction between the second base station <NUM> and the first base station <NUM>.

Next, the first base station <NUM> may send a transfer request to the third base station <NUM> in "transfer request" for example after judging the above predetermined transfer condition is satisfied according to the received information of the mobility measurement result, then the third base station <NUM> performs the first admission control according to the transfer request, and sends a response to the transfer request to the first base station <NUM> in "transfer response" for example so as to notify the result of the first admission control to the first base station <NUM>. The result of the first admission control indicates whether the third base station <NUM> can accept all the radio bearers between the user equipment <NUM> and the second base station <NUM> or which part of the radio bearers can be accepted by the third base station <NUM>.

Thereafter, the first base station <NUM> or the third base station <NUM> notifies the result of the first admission control to the second base station <NUM> in "transfer notification" for example, and the first base station <NUM> or the second base station <NUM> notifies the user equipment <NUM> to perform the transfer procedure in "transfer confirmation" for example according to the result and the transfer response of the third base station <NUM>. The specific contents contained in the notification message "transfer confirmation" have been described above, and no repeated description will be made herein.

Preferably, if the result of the first admission control performed by the third base station <NUM> indicates that the third base station <NUM> can not accept all the radio bearers between the user equipment <NUM> and the second base station <NUM>, the first base station <NUM> may perform the second admission control according to the result of the first admission control contained in the received "transfer response", as shown by broken-line block in <FIG>. It is to be understood that by performing the second admission control by the first base station <NUM> to transfer at least part of the radio bearers that can not be accepted by the third base station <NUM> to the first base station <NUM>, it is possible to further ensure the user equipment <NUM> obtains excellent service quality. This is merely a preferred example of course but not limitation, and it is also possible to directly notify the user equipment <NUM> to release the services unacceptable by the third base station <NUM> after performing the first admission control, without performing the second admission control by the first base station <NUM>. After judging through the first admission control and/or the second admission control, the second base station <NUM> releases the radio bearers which are originally transmitted by the second base station <NUM> and which can not be accepted by the third base station <NUM> and the first base station <NUM>, and notifies the core network to release core network bearers corresponding to the radio bearers.

It is to be noted that in this case, the first base station <NUM> may notify the final result about the first admission control and the second admission control to the second base station <NUM> in "transfer notification" for example after performing the second admission control, then the first base station <NUM> or the second base station <NUM> notifies the final result to the user equipment <NUM> in "transfer confirmation" for example, and thus the radio bearer acceptable by the third base station can be transferred to the third base station <NUM> and the radio bearer acceptable by the first base station <NUM> can be transferred to the first base station <NUM>.

After receiving the above notification message "transfer confirmation", the user equipment <NUM> releases the services that can not be accepted by the first base station <NUM> and the third base station <NUM>, releases the wireless data connection with the second base station <NUM> and performs the synchronized access operation to the third base station <NUM>.

A basic signaling flow of the transfer procedure in a case that the first base station <NUM> serves as the triggering node has been described in detail with reference to <FIG> above, and next, an example of a scene of the transfer procedure in a case that the second base station <NUM> serves as the triggering node will be described in detail with reference to <FIG>.

As shown in <FIG>, since the triggering node is the second base station <NUM> at this time, the user equipment <NUM> only needs to notify the carrier mobility measurement result to the second base station <NUM>, and the second base station <NUM> sends the transfer request to the third base station <NUM> after judging the predetermined transfer condition is satisfied according to the measurement result so as to trigger the transfer procedure. Then, the third base station <NUM> sends to the second base station <NUM> a response message "transfer response" for the transfer request after performing the first admission control, so as to notify the result of the first admission control to the second base station <NUM>. Next, the second base station <NUM> or the third base station <NUM> may notify the result to the first base station <NUM>, and the second base station <NUM> sends the notification message to the user equipment <NUM> in "transfer confirmation" according to the received "transfer response".

Preferably, similar to the case described in <FIG>, the first base station <NUM> may also perform the second admission control according to the received result of the first admission control. Specifically, when the "transfer response" of the third base station <NUM> received by the second base station <NUM> indicates that the third base station <NUM> can not accept all the radio bearers between the user equipment <NUM> and the second base station <NUM>, the second base station <NUM> sends "transfer request" to the first base station <NUM> with respect to the radio bearers that can not be by the third base station <NUM>, the first base station <NUM> performs the second admission control according to the "transfer request" and notifies the final result of the admission control to the second base station <NUM> in "transfer response" for example. Then, the second base station <NUM> sends a notification to the user equipment <NUM> according to the final result. In this example, the "transfer response" sent by the first base station includes for which part of the radio bearers of the user equipment that the first base station <NUM> can perform communication.

As can be seen from comparison of <FIG>, the transfer procedures in these two cases are similar to each other, and the difference only lies in that the base stations serving as the triggering node are different, thereby leading to differences in transmitting and receiving nodes and timings for some signaling. Therefore, parts which are not described in detail in <FIG> can be referred to <FIG>, and no repeated description will be made herein.

Examples of scenes for basic signaling interactions of the transfer procedure in different cases have been described in detail with reference to <FIG>, and examples of scenes for data forwarding and path switch among network nodes in different cases after the basic signaling interaction of the transfer procedure will be described in detail with reference to <FIG> below.

<FIG> is a schematic diagram illustrating an exemplary scene in a case that the data of the first, second and third base stations is directly routed from the core network before triggering the transfer procedure and after completing triggering of the transfer procedure and synchronized access to the third base station by the user equipment succeeds according to an embodiment of the disclosure.

Specifically, if the data of the first base station <NUM>, the second base station <NUM> and the third base stations <NUM> is directly routed from the core network before triggering the transfer procedure and after completing triggering of the transfer procedure, the second base station <NUM> performs data forwarding operation to forward data of a first radio bearer acceptable by the third base station <NUM> to the third base station <NUM> according to the result of the first admission control, and further performs data forwarding operation to forward data of a second radio bearer acceptable by the first base station <NUM> to the first base station <NUM> according to the result of the second admission control, and the first base station <NUM> or the second base station <NUM> notifies the core network to switch a path corresponding to the second radio bearer to the first base station <NUM>.

It is to be noted that if the result of the first admission control indicates that the third base station <NUM> can accept all the radio bearers, then only data of the first radio bearer accepted by the third base station <NUM> is needed to be forwarded to the third base station <NUM>, otherwise, data of the second radio bearer accepted by the first base station <NUM> also needs to be forwarded to the first base station <NUM> at the same time.

After the data forwarding operation, as shown in <FIG>, if the synchronized access to the third base station <NUM> by the user equipment <NUM> succeeds, the third base station <NUM> notifies the core network to switch a path corresponding to the first radio bearer to the third base station <NUM>. Specifically, the third base station <NUM> may send "path switch request" for example to a mobility management entity (MME). After receiving the request, the mobility management entity sends "bearer modifying request" for example to a gateway , and after receiving the request, the gateway performs switching downlink path operation and thus the data of the first radio bearer acceptable by the third base station <NUM> is directly routed to the third base station <NUM>, and the gateway sends to the second base station <NUM> an end flag to inform a number of a last data packet forwarded to the third base station <NUM> via the second base station <NUM>. Thereafter, the gateway sends "bearer modifying response" for example to the mobility management entity, and meanwhile, after receiving the response, the mobility management entity sends "path switch confirmation" for example as confirmation for the path switch request. Then, the third base station <NUM> may notify the second base station <NUM> to release relevant user equipment information, and the second base station <NUM> may release the resources related to the user equipment <NUM> and services thereof after receiving the notification.

Otherwise, as shown in <FIG>, if the synchronized access to the third base station <NUM> by the user equipment <NUM> fails, the user equipment <NUM> will notify the first base station <NUM>, and the first base station <NUM> performs a third admission control to perform admission control on the first radio bearer and notifies the second base station <NUM> and the third base station <NUM> after the third admission control, to notify the failure of the synchronized access and cause data of a third radio bearer acceptable by the first base station <NUM> in the first radio bearer to be forwarded to the first base station <NUM>. The first base station <NUM> also notifies the core network to switch a path corresponding to the third radio bearer to the first base station <NUM>. Meanwhile, the first base station <NUM> notifies the user equipment <NUM> of which data can be transmitted over carriers of the first base station <NUM> and which data needs to be released, notifies the second base station <NUM> and the third base station <NUM> of which radio bearers should be released and notifies the core network to release core network bearers corresponding to the radio bearers.

It is to be noted that in a case that the synchronized access fails, as shown in <FIG>, except that the mobility management entity is notified by the first base station <NUM> at this time, specific path switch operations related to the core network end are similar to the procedure as described above with reference to <FIG>, and thus, no repeated description will be made herein.

As can be seen from the above description with reference to <FIG> and <FIG>, for the second radio bearer determined according to the result of the second admission control performed by the first base station <NUM>, irrespective of success or failure of the synchronized access to the third base station <NUM> by the user equipment <NUM>, the core network is notified to switch corresponding path to the first base station <NUM>. As for the first radio bearer determined according to the result of the first admission control performed by the third base station <NUM>, only if the synchronized access to the third base station <NUM> by the user equipment <NUM> succeeds, the core network is notified to switch path corresponding to the first radio bearer to the third base station <NUM>, and if the synchronized access fails, the first base station <NUM> performs the third admission control for the first radio bearer and notifies the core network to switch path corresponding to the third radio bearer determined according to the result of the third admission control to the first base station <NUM>. That is to say, for the services corresponding to the second radio bearer and the third radio bearer which are originally provided by the second base station <NUM>, the first base station <NUM> provides these services at this time. Further, in a case that the synchronized access fails, it also needs to notify the user equipment <NUM> that the third radio bearer should be transferred to the first base station <NUM> for transmission and to notify the user equipment <NUM> to release the radio bearers unacceptable by the first base station <NUM> after the third admission control.

Next, exemplary scenes in a case that the data of the second base station <NUM> is forwarded via the first base station <NUM> will be described with reference to <FIG>, <FIG> and <FIG>. <FIG> is a schematic diagram illustrating an exemplary scene in a case that the data of the second base station and the third base station is forwarded via the first base station and the synchronized access to the third base station by the user equipment succeeds according to an embodiment of the disclosure; <FIG> is a schematic diagram illustrating another exemplary scene in a case that the data of the second base station and the third base station is forwarded via the first base station and the synchronized access to the third base station by the user equipment succeeds according to an embodiment of the disclosure; <FIG> is a schematic diagram illustrating an exemplary scene in a case that the data of the second base station is forwarded via the first station while the data of the third base station is directly routed from the core network after completing triggering of the transfer procedure and the synchronized access to the third base station by the user equipment succeeds according to an embodiment of the disclosure; and <FIG> is a schematic diagram illustrating an exemplary scene in a case that the data of the second base station is forwarded via the first base station and the synchronized access to the third base station by the user equipment fails according to an embodiment of the disclosure.

Specifically, if the data of the second base station <NUM> and the third base station <NUM> is forwarded from the first base station <NUM>, the first base station <NUM> stops forwarding data to the second base station <NUM> after completing confirmation for the first admission control or completing the second admission control, and the second base station <NUM> performs data forwarding operation according to the result of the first admission control to forward the data of the first radio bearer acceptable by the third base station <NUM> to the third base station <NUM> and also performs data forwarding operation according to the result of the second admission control to forward the data of the second radio bearer acceptable by the first base station <NUM> to the first base station <NUM>.

At this time, the data of the second base station <NUM> is forwarded from the first base station <NUM>, and thus the first base station <NUM> also needs to perform data forwarding operation for the third base station <NUM>, and the first base station <NUM> may perform, after completing confirmation for the first admission control, the data forwarding operation simultaneously with the second base station <NUM> so as to forward the data of the first radio bearer to the third base station <NUM> regardless of success or failure of the synchronized access between the user equipment <NUM> and the third base station <NUM>, as shown in <FIG>. Alternatively, the first base station <NUM> may also perform data forwarding operation only after acquiring the success of the synchronized access between the user equipment <NUM> and the third base station <NUM>, as shown in <FIG>, which is more suitable for a situation in which the first base station <NUM> and the second base station <NUM> transmit services for one same radio bearer at the same time.

Further, the second base station <NUM> automatically releases resources related to the services of the user equipment <NUM> after completing the data forwarding operation.

Particularly, if the result of the first admission control indicates that the third base station <NUM> can not accept all the radio bearers, while the data forwarding operation for the first radio bearer accepted by the third base station <NUM> is performed, in addition to stopping forwarding data to the second base station <NUM> by the first base station <NUM>, the second base station <NUM> also needs to transfer the data of the second radio bearer accepted by the first base station <NUM> back to the first base station <NUM> for transmission.

Alternatively, as shown in <FIG>, if the data of the second base station <NUM> is forwarded from the first base station <NUM> while the data of the third base station <NUM> is directly routed from the core network after completing triggering of the transfer procedure, in a case that the synchronized access to the third base station <NUM> by the user equipment <NUM> succeeds, in addition to the processing procedures described above with reference to <FIG>, operations at the core network end are also involved, that is, the third base station <NUM> needs to notify the core network to modify the core network bearer corresponding to the first radio bearer acceptable by the third base station <NUM>. Specifically, after the synchronized access to the third base station <NUM> by the user equipment <NUM> succeeds, the third base station <NUM> further sends "path switch request" for example to the mobility management entity, the mobility management entity sends, after receiving the request, "bearer modifying request" for example to the gateway, and the gateway performs switching downlink path operation after receiving the request and thus the data of the first radio bearer acceptable by the third base station <NUM> is directly routed to the third base station <NUM>, and the gateway sends an end flag to the first base station <NUM> to inform the number of the last data packet forwarded to the third base station <NUM> via the first base station. Thereafter, the gateway sends "bearer modifying response" for example to the mobility management entity, and the mobility management entity sends, after receiving the response, "path switch confirmation" for example as confirmation for the "path switch request" to the third base station <NUM>, thereby notifying the third base station <NUM> of completion of the path switch operation at the core network end.

However, if the synchronized access to the third base station <NUM> by the user equipment <NUM> fails, as shown in <FIG>, similar to the scene described with reference to <FIG>, the user equipment <NUM> first notifies the first base station <NUM>, the first base station <NUM> stops forwarding data to the third base station <NUM> after receiving the notification, and the first base station <NUM> notifies the second base station <NUM> and the third base station <NUM> after performing the third admission control to notify the failure of the synchronized access and cause the second base station <NUM> and the third base station <NUM> to perform data forwarding operation for the third radio bearer acceptable by the first base station <NUM> in the first radio bearer, so that the data of the third radio bearer acceptable by the first base station <NUM> in the first radio bearer is forwarded to the first base station <NUM> and the radio bearer unacceptable by the first base station <NUM> in the first radio bearer is released. Meanwhile, the first base station <NUM> notifies the user equipment <NUM> of which data can be transmitted over carriers of the first base station <NUM> and which data needs to be released.

As can be seen from above description with reference to <FIG> and <FIG>, under these scenes, the first base station <NUM> is responsible for forwarding data to other base stations in the wireless communication system, and thus, no path switch operation at the core network end will be involved in both cases of success and failure of the synchronized access operation.

Further, it is to be noted that although <FIG> shows that the first base station <NUM> and the second base station <NUM> performs data forwarding operation for the third base station <NUM> at the same time, but this is merely an example, and similar to <FIG>, the first base station <NUM> may also not perform data forwarding operation for the third base station <NUM> at first, which is not limited herein.

Exemplary scenes in a case that the data of the first base station is forwarded via the second base station will be described with reference to <FIG> and <FIG> below. <FIG> is a schematic diagram illustrating an exemplary scene in a case that the data of the first base station is forwarded via the second base station and the synchronized access to the third base station by the user equipment succeeds according to an embodiment of the disclosure; and <FIG> is a schematic diagram illustrating an exemplary scene in a case that the data of the first base station is forwarded via the second base station and the synchronized access to the third base station by the user equipment fails according to an embodiment of the disclosure.

Specifically, if the data of the first base station <NUM> is forwarded via the second base station <NUM>, the second base station <NUM> performs data forwarding operation according to the result of the first admission control to forward the data of the first radio bearer acceptable by the third base station <NUM> to the third base station <NUM>, and performs data forwarding operation according to the result of the second admission control to forward the data of the second radio bearer acceptable by the first base station <NUM> to the first base station <NUM>.

If the synchronized access to the third base station <NUM> by the user equipment <NUM> succeeds, as shown in <FIG>, the third base station <NUM> triggers the core network to perform path switch to route the data sent from the core network to the second base station <NUM> directly to the third base station <NUM>, and after completing the path switch, the third base station <NUM> starts forwarding the data of downlink bearer transmitted via the first base station <NUM> to the first base station <NUM>, and the second base station <NUM> releases information related to the user equipment and services thereof after completing the data forwarding operation. Specifically, after succeeding in the synchronized access, the third base station <NUM> sends "path switch request" for example to the mobility management entity, the mobility management entity sends, after receiving the request, "bearer modifying request" for example to the gateway, and the gateway performs switching downlink path operation after receiving the request and thus the data of the first radio bearer acceptable by the third base station <NUM> is directly routed to the third base station <NUM>, and the gateway sends an end flag to the second base station <NUM>. Then, the second base station <NUM> forwards this end flag to the first base station <NUM> to inform the first base station of the number of last data packet forwarded via the second base station <NUM>. Thereafter, the gateway sends "bearer modifying response" for example to the mobility management entity, and the mobility management entity sends "path switch confirmation" for example as confirmation for the "path switch request" to the third base station <NUM> after receiving the response, and thus notifies the third base station <NUM> that the path switch operation at the core network end has been completed.

As can be seen from <FIG>, in a case that the synchronized access succeeds, after receiving the end flag for the services transmitted by the first base station <NUM>, the second base station <NUM> forwards the flag to the first base station <NUM>, and then releases all resources related to the user equipment <NUM> after receiving a message "user equipment information release" sent by the third base station <NUM> and/or the first base station <NUM>.

Otherwise, if the synchronized access to the third base station <NUM> by the user equipment <NUM> fails, then as shown in <FIG>, the user equipment <NUM> notifies the first base station <NUM>, and the first base station <NUM> notifies the second base station <NUM> and the third base station <NUM> after performing the third admission control to notify the failure of the synchronized access and cause the second base station <NUM> and the third base station <NUM> perform data forwarding operation for the third radio bearer acceptable by the first base station <NUM> in the first radio bearer, and meanwhile notifies the user equipment <NUM> of which data can be transmitted over carriers of the first base station <NUM> and which data needs to be released.

Preferably, in the case that the synchronized access fails, the data of the services transmitted by the first base station <NUM> (that is, data of the original services of the first base station <NUM>, data of the second radio bearer and data of the third radio bearer) may also be forwarded to the first base station <NUM> via the second base station <NUM>. In this case, when switching needs to be performed among small base stations, there always exists one anchor base station (for example, the second base station <NUM> herein ) being responsible for data forwarding, and thus it only needs to notify the anchor base station of the transfer the data forwarding.

However, alternatively, it is also possible that after completing the third admission control by the first base station <NUM> , the first base station <NUM> or the second base station <NUM> notifies the core network to perform path switch for the data of all the radio bearers accepted by the first base station <NUM>, so that the path corresponding to the data forwarded to the first base station <NUM> via the second base station <NUM> is switched to the first base station <NUM> and the core network bearer corresponding to the radio bearer unacceptable by the first base station <NUM> in the first radio bearer is released, and meanwhile notifies the user equipment <NUM> to release the radio bearer unacceptable by the first base station <NUM> in the first radio bearer.

It is to be noted that in the case that the synchronized access fails, as shown in <FIG>, except that the mobility management entity is notified by the first base station <NUM> or the second base station <NUM> at this time, specific path switch operations involving the core network are similar to those described above with reference to <FIG>, and thus no repeated description will be made herein.

Although data forwarding and path switch operations after the transfer procedure in various situations have been described above with reference to <FIG>, it should be understood that the drawings and related description thereof are only examples but not limitation, and those skilled in the art may modify the above procedures according to the principle of the invention. For example, although in the above the first base station <NUM> and the third base station <NUM> together undertake at least part of the services originally provided by the second base station <NUM>, it is also possible that the third base station <NUM> undertakes this individually, while for the services unacceptable by the third base station <NUM>, the user equipment <NUM> is notified to release this part of the services. Further, although it only shows the second base station <NUM> performs data forwarding operation to the third base station <NUM> in <FIG>, this is merely for the purpose of clarity of illustration but not limitation, it should be understood that in a case that the first base station <NUM> performs admission control, the second base station <NUM> also performs data forwarding operation to the first base station <NUM> with respect to the radio bearer accepted by the first base station <NUM>.

Further, it should be noted that for the purpose of clarity, only signaling interactions closely related to the disclosure are shown in the drawings, and for other well-known signaling interactions in the art, no detailed description will be made herein.

As can be understood from the above detailed description of the embodiments of the disclosure, by performing the above transfer procedure in the case that the predetermined transfer condition is satisfied, it is possible to ensure the user equipment obtains optimized service quality while improving data transmission efficiency.

An example of functional configuration of a first base station serving as the connection maintaining node according to an embodiment of the disclosure will be described with reference to <FIG> below. <FIG> is a block diagram illustrating an example of functional configuration of a first base station serving as the connection maintaining node according to an embodiment of the disclosure.

As shown in <FIG>, the first base station <NUM> according to the present embodiment may include a measurement result receiving unit <NUM>, a judging unit <NUM>, a transfer request sending unit <NUM> and a transfer response receiving unit <NUM>. Examples of functional configurations of respective units will be described in detail below.

The measurement result receiving unit <NUM> may be configured to receive, in a case that the first base station <NUM> is the triggering node to trigger the above transfer procedure, a mobility measurement result regarding the serving carrier between the user equipment and the second base station from the user equipment or the second base station as the connection transfer source node.

The judging unit <NUM> may be configured to judge whether the predetermined transfer condition of transferring the services provided to the user equipment by the second base station to the third base station is satisfied based on the mobility measurement result received by the measurement result receiving unit <NUM>.

The transfer request sending unit <NUM> may be configured to send a transfer request to the third base station as the connection transfer target node in a case that the judging unit <NUM> judges the predetermined transfer condition is satisfied, so as to trigger the user equipment to release the wireless data connection with the second base station and establish the wireless data connection with the third base station, and thus the first base station and the third base station perform wireless data connection with the user equipment over different carriers. Particularly, at least part of the services originally provided by the second base station is transferred to the third base station.

The transfer response receiving unit <NUM> may be configured to receive from the third base station the transfer response which may include the result of the admission control performed by the third base station.

Preferably, the first base station <NUM> may further include a first admission control performing unit <NUM>. The first admission control performing unit <NUM> may be configured to perform, in a case that the admission control result contained in the transfer response received by the transfer response receiving unit <NUM> indicates that the third base station can not accept all radio bearers of the second base station, admission control for radio bearer unacceptable by the third base station, so that the radio bearer acceptable by the first bases station can be transferred to the first base station <NUM>.

Also, optionally, the first base station <NUM> may further include a notifying unit <NUM>. The notifying unit <NUM> may be configured to notify the result of the admission control performed by the third base station and optionally the result of the admission control performed by the first base station to the user equipment and/or the second base station.

Further, optionally, the first base station <NUM> may further include a data forwarding unit <NUM>. The data forwarding unit <NUM> may be configured to perform data forwarding to the third base station in a case that the data of the second base station is forwarded via the first base station. Preferably, the data forwarding unit <NUM> may perform data forwarding simultaneously with the second base station after completing the basic signaling interaction of the transfer procedure, or may perform the data forwarding only after receiving a message that the synchronized access between the user equipment and the third base station succeeds.

Preferably, the first base station <NUM> may further include a second admission control performing unit <NUM>. The second admission control performing unit <NUM> may be configured to perform, in a case that the synchronized access between the user equipment and the third base station fails, admission control for the radio bearer that should be accepted by the third base station originally, so that the radio bearer acceptable by the first base station is transferred to the first base station <NUM>.

Further, preferably, the first base station <NUM> may further include a core network notifying unit <NUM>. The core network notifying unit <NUM> may be configured to notify the core network to switch the path corresponding to the radio bearer accepted by the first base station to the first base station in a case that the data of the second base station comes directly from the core network.

It is to be understood that all of the first admission control performing unit <NUM>, the notifying unit <NUM>, the data forwarding unit <NUM>, the second admission control performing unit <NUM> and the core network notifying unit <NUM> are optional, which are shown in broken-line blocks in <FIG>, and those skilled in the art may combine one or more of the above described units as required for example, and any such combinations are considered to fall within the scope of the disclosure.

Next, an example of functional configuration of the first base station serving as the connection maintaining node according to another embodiment of the disclosure will be described with reference to <FIG> is a block diagram illustrating an example of functional configuration of the first base station serving as the connection maintaining node according to another embodiment of the disclosure. Except for providing a receiving unit <NUM> instead of the measurement result receiving unit <NUM>, the transfer request sending unit <NUM>, the judging unit <NUM> and the transfer response receiving unit <NUM>, the functional configuration of the first base station <NUM> as shown in <FIG> is the same as that of the first base station <NUM> described above with reference to <FIG>, and thus some description will be omitted as appropriate.

The receiving unit <NUM> may be configured to receive a notification regarding the transfer procedure from the second base station or the third base station serving as the connection transfer target node in a case that the above transfer procedure is triggered by the second base station serving as the connection transfer source node, and the notification may include the result of the admission control performed by the third base station.

Further, for the optional first admission control performing unit <NUM>, the notifying unit <NUM>, the data forwarding unit <NUM>, the second admission control performing unit <NUM> and the core network notifying unit <NUM> as shown in broken-line blocks in <FIG>, functional configurations thereof are the same as those of corresponding units described above with reference to <FIG>, and no repeated description will be made herein.

Next, an example of functional configuration of the second base station serving as the connection transfer source node according to an embodiment of the disclosure will be described with reference to <FIG> is a block diagram illustrating an example of functional configuration of the second base station serving as the connection transfer source node according to an embodiment of the disclosure.

As shown in <FIG>, the second base station <NUM> according to the embodiment of the disclosure may include a receiving unit <NUM>. The receiving unit <NUM> may be configured to receive a notification regarding the transfer procedure from the first base station or the third base station serving as the connection transfer target node in a case that the transfer procedure is triggered by the first base station serving as the connection maintaining node, and the notification may include the result of the admission control performed by the third base station and optionally the result of the admission control performed by the first base station.

Optionally, the second base station <NUM> may further include a user equipment notifying unit <NUM>. The user equipment notifying unit <NUM> may be configured to notify the user equipment of the result of the admission control performed by the third base station and optionally the result of the admission control performed by the first base station.

Optionally, the second base station <NUM> may further include a data forwarding unit <NUM>. The data forwarding unit <NUM> may be configured to perform data forwarding operation to the third base station and optionally the first base station, so as to forward the data of the radio bearers acceptable by the third base station and the first base station to the third base station and the first base station respectively.

Optionally, the second base station <NUM> may further include a core network notifying unit <NUM>. The core network notifying unit <NUM> may be configured to notify the core network to switch the path corresponding to the radio bearer acceptable by the first base station to the first base station in a case that the data of the second base station directly comes from the core network.

Next, an example of the functional configuration of the second base station serving as the connection transfer source node according to another embodiment of the disclosure will be described with reference to <FIG> is a block diagram illustrating an example of the functional configuration of the second base station serving as the connection transfer source node according to another embodiment of the disclosure. Except for providing a measurement result receiving unit <NUM>, a judging unit <NUM>, a transfer request sending unit <NUM> and a transfer response receiving unit <NUM> instead of the receiving unit <NUM> of the second base station <NUM> as shown in <FIG>, the functional configuration of the second base station <NUM> as shown in <FIG> is the same as that of the second base station <NUM> as shown in <FIG>, and thus description thereof will be omitted as appropriate.

The measurement result receiving unit <NUM> may be configured to receive a mobility measurement result regarding a serving carrier between the user equipment and the second base station from the user equipment.

The judging unit <NUM> may be configured to judge whether a predetermined transfer condition of transferring the services provided to the user equipment by the second base station to the third base station is satisfied according to the mobility measurement result received by the measurement result receiving unit <NUM>.

The transfer request sending unit <NUM> may be configured to send a transfer request to the third base station serving as the connection transfer target node in a case that the judging unit <NUM> judges the predetermined transfer condition is satisfied, so as to trigger the user equipment to release the wireless data connection with the second base station and establish the wireless data connection with the third base station, and thus the first base station serving as the connection maintaining node and the third base station perform wireless data connection with the user equipment over different carriers, so that at least part of the services originally provided by the second base station is transferred to the third base station.

The transfer response receiving unit <NUM> may be configured to receive from the third base station a transfer response which may include the result of the admission control performed by the third base station.

Further, preferably, the third base station <NUM> may further include a transfer confirmation receiving unit <NUM>. The transfer confirmation receiving unit <NUM> may be configured to receive from the first base station a transfer confirmation which may include the result of the admission control performed by the first base station.

Further, for a user equipment notifying unit <NUM>, a data forwarding unit <NUM> and a core network notifying unit <NUM> as shown in broken-line blocks in <FIG>, functional configurations thereof are the same as those of the user equipment notifying unit <NUM>, the data forwarding unit <NUM> and the core network notifying unit <NUM> described above with reference to <FIG>, and no repeated description will be made herein.

Further, it is to be noted that similar to the cases as shown in <FIG> and <FIG>, the constitute units as shown in broken-line blocks in <FIG> and <FIG> are optional, and those skilled in the art may combine one or more of these units according to actual requirements, and any such combinations are considered to fall within the scope of the disclosure.

Next, an example of functional configuration of the third base station serving as the connection transfer target node according to an embodiment of the disclosure will be described with reference to <FIG> is a block diagram illustrating an example of functional configuration of the third base station serving as the connection transfer target node according to an embodiment of the disclosure.

As shown in <FIG>, the third base station <NUM> according to the embodiment of the disclosure may include a transfer request receiving unit <NUM>, an admission control performing unit <NUM> and a transfer response sending unit <NUM>.

The transfer request receiving unit <NUM> may be configured to receive a transfer request regarding the transfer procedure from the first base station serving as the connection maintaining node or the second base station serving as the connection transfer source node which is the triggering node to make the user equipment release the wireless data connection with the second base station, and in a case that the synchronized access between the user equipment and the third base station succeeds, the first base station and the third base station perform wireless data connection with the user equipment over different carriers so that at least part of the services originally provided by the second base station is transferred to the third base station.

The admission control performing unit <NUM> may be configured to perform the admission control according to the transfer request received by the transfer request receiving unit <NUM> so as to determine the radio bearer of the second base station acceptable by the third base station.

The transfer response sending unit <NUM> may be configured to send a transfer response which may include the result of the admission control performed by the third base station to the first base station or the second base station which is the triggering node for the transfer procedure.

Optionally, the third base station <NUM> may further include a core network notifying unit <NUM>. The core network notifying unit <NUM> may be configured to notify the core network to switch the path corresponding to the radio bearer acceptable by the third base station to the third base station in a case that the data of the second base station directly comes from the core network or the data of the first base station is forwarded via the second base station and the synchronized access between the user equipment and the third base station succeeds.

Further, optionally, the third base station <NUM> may further include a data forwarding unit <NUM>. The data forwarding unit <NUM> may be configured to perform data forwarding to the first base station in a case that the synchronized access between the user equipment and the third base station fails, so as to forward the data of the radio bearer acceptable by the first base station in the radio bearer originally accepted by the third base station to the first base station.

It is to be understood that both of the core network notifying unit <NUM> and the data forwarding unit <NUM> as shown in broken-line blocks in <FIG> are optional, and those skilled in the art may combine one or more of these units according to actual requirements and any such combinations are considered to fall within the scope of the disclosure.

Next, an example of functional configuration of the user equipment according to an embodiment of the disclosure will be described with reference to <FIG> is a block diagram illustrating an example of functional configuration of the user equipment according to an embodiment of the disclosure.

As shown in <FIG>, the user equipment <NUM> according to the embodiment of the disclosure may include a measurement result reporting unit <NUM>, a first notification receiving unit <NUM> and a synchronized accessing unit <NUM>.

The measurement result reporting unit <NUM> may be configured to report a mobility measurement result regarding a serving carrier between the user equipment and the second base station serving as the connection transfer source node to the second base station and optionally the first base station serving as the connection maintaining node, so as to serve as reference for the triggering node to judge whether the predetermined transfer condition of transferring the services provided to the user equipment by the second base station to the third base station is satisfied.

The first notification receiving unit <NUM> may be configured to receive a notification regarding the transfer procedure from the first base station or the second base station, and the notification may include the result of the admission control performed by the third base station serving as the connection transfer target node and optionally the result of the admission control performed by the first base station.

The synchronized accessing unit <NUM> may be configured to perform the synchronized access to the third base station according to the notification received by the first notification receiving unit <NUM>.

Preferably, the user equipment <NUM> may further include a second notification receiving unit <NUM>. The second notification receiving unit <NUM> may be configured to receive a notification from the first base station in a case that the synchronized access to the third base station by the user equipment fails, the notification including information about which data of the user equipment may be transmitted over the carrier of the first base station and which data needs to be released.

Similarly, the second notification receiving unit <NUM> as shown in broken-line block in <FIG> is also optional.

It is to be noted that although the examples of the functional configurations of the first base station, the second base station, the third base station and the user equipment in the wireless communication system according to the embodiments of the disclosure have been described above with reference to <FIG>, it should be understood that this constructs no limitation on the disclosure, and those skilled in the art may combine, sub-combine and alter the above configurations according to the principle of the disclosure.

Next, an example of a procedure of a method used in the wireless communication system according to an embodiment of the disclosure will be described with reference to <FIG> is a flow chart illustrating an example of a procedure of a method used in the wireless communication system according to an embodiment of the disclosure. The wireless communication system may include a first base station, a second base station, a third base station and user equipment, and the first base station and the second base station perform wireless data connection with the user equipment over different carriers.

As shown in <FIG>, the method <NUM> according to the embodiment of the disclosure may include a judging step S1602 and a triggering step S1604.

In the judging step S1602, whether the predetermined transfer condition of transferring the services provided to the user equipment by the second base station to the third base station is satisfied may be judged by the triggering node. The triggering node may be the first base station serving as the connection maintaining node or the second base station serving as the connection transfer source node.

Next, in the triggering step S1604, the transfer procedure may be triggered in a case that it is judged the predetermined transfer condition is satisfied, so as to make the user equipment release the wireless data connection with the second base station and establish the wireless data connection with the third base station, and thus the first base station and the third base station perform wireless data connection with the user equipment over different carriers. Particularly, at least part of the services originally provided by the second base station is transferred to the third base station.

Preferably, the above transfer procedure also causes part of the services originally provided by the second base station to be transferred to the first base station.

Further, preferably, the triggering node sends a transfer request to the third base station if it judges the predetermined transfer condition is satisfied according to a received mobility measurement result regarding a serving carrier of the second base station, and the third base station performs the first admission control according to the transfer request and sends a transfer response to the triggering node to notify the result of the first admission control.

Further, preferably, if the result of the first admission control indicates that the third base station can not accept all radio bearers between the user equipment and the second base station, the first base station performs the second admission control according to the result of the first admission control and notifies the second base station of the result of the second admission control.

Further, preferably, the first base station or the second base station sends, after acquiring the final result of the first admission control or the second admission control, a notification message to the user equipment to notify the user equipment to perform the transfer procedure according to the final result and the transfer response of the third base station, the notification message including at least one of the following: for which part of the radio bearer of the user equipment that the first base station can perform communication, for which part of the radio bearer of the user equipment that the third base station can perform communication, a dedicated preamble code as required when making synchronized access to the third base station, system information of a carrier for communication between the user equipment and the third base station, and configuration information of a control plane protocol for establishing communication between the user equipment and the third base station. Further, the user equipment releases, after receiving the notification message, the radio bearers unacceptable by the first base station and the third base station, and releases the wireless data connection with the second base station and performs synchronized access to the third base station at the same time.

It is to be understood that the method used in the wireless communication system according to the embodiment of the disclosure corresponds to the embodiments of the wireless communication system described above, and thus parts which are not described in detail herein may be referred to the foregoing description at previous corresponding positions, and no repeated description will be made herein.

Further, the embodiment of the disclosure also provides a storage medium including machine readable program codes which when executed on an information processing apparatus, cause the information processing apparatus to perform the method used in the wireless communication system according to the embodiment of the disclosure as described above, the method including the following steps: a judging step of judging, by a triggering node, whether a predetermined transfer condition for transferring services provided to user equipment by a second base station to a third base station is satisfied; and a triggering step of triggering the transfer procedure if it is judged that the predetermined transfer condition is satisfied, so that the user equipment releases wireless data connection with the second base station and establishes wireless data connection with the third base station, and thus a first base station and the third base station perform wireless data connection with the user equipment over different carriers, wherein at least part of the services originally provided by the second base station is transferred to the third base station. Particularly, the first base station, the second base station, the third base station and the user equipment are included in a wireless communication system, and the first base station and the second base station perform wireless data connection with the user equipment over different carriers.

Further, the embodiment of the disclosure also provides a program product including machine executable instructions which when executed on an information processing apparatus cause the information processing apparatus to perform the method used in the wireless communication system according to the embodiment of the disclosure as described above, the method including the following steps: a judging step of judging, by a triggering node, whether a predetermined transfer condition for transferring services provided to user equipment by a second base station to a third base station is satisfied; and a triggering step of triggering the transfer procedure if it is judged that the predetermined transfer condition is satisfied, so that the user equipment releases wireless data connection with the second base station and establishes wireless data connection with the third base station, and thus a first base station and the third base station perform wireless data connection with the user equipment over different carriers, wherein at least part of the services originally provided by the second base station is transferred to the third base station. Particularly, the first base station, the second base station, the third base station and the user equipment are included in a wireless communication system, and the first base station and the second base station perform wireless data connection with the user equipment over different carriers.

It should be appreciated that the machine executable instructions in the storage medium and the program product according to the embodiments of the disclosure may also be configured to perform the methods corresponding to the embodiments of the wireless communication system described above, and thus parts which are not described in detail herein may be referred to description at previous corresponding positions, and no repeated description will be made herein.

Accordingly, a storage medium on which the above program product storing machine readable instruction codes is carried is also included in the disclosure of the invention. The storage medium includes but not limited to a floppy disk, an optical disk, a magneto-optical disk, a storage card, a memory rod and the like.

Furthermore, it shall be noted that the foregoing series of processes and apparatuses can also be embodied in software and/or firmware. In the case of being embodied in software and/or firmware, a program constituting the software is installed from a storage medium or a network to a computer with a dedicated hardware structure, e.g., a general purpose personal computer <NUM> illustrated in <FIG>, which can perform various functions when various programs are installed thereon.

In <FIG>, a Central Processing Unit (CPU) <NUM> performs various processes according to a program stored in a Read Only Memory (ROM) <NUM> or loaded from a storage portion <NUM> into a Random Access Memory (RAM) <NUM> in which data required when the CPU <NUM> performs the various processes is also stored as needed.

The CPU <NUM>, the ROM <NUM> and the RAM <NUM> are connected to each other via a bus <NUM> to which an input/output interface <NUM> is also connected.

The following components are connected to the input/output interface <NUM>: an input portion <NUM> including a keyboard, a mouse, etc.; an output portion <NUM> including a display, e.g., a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), etc., a speaker, etc.; a storage portion <NUM> including a hard disk, etc.; and a communication portion <NUM> including a network interface card, e.g., an LAN card, a modem, etc. The communication portion <NUM> performs a communication process over a network, e.g., the Internet.

A driver <NUM> is also connected to the input/output interface <NUM> as needed. A removable medium <NUM>, e.g., a magnetic disk, an optical disk, an magneto optical disk, a semiconductor memory, etc., can be installed on the driver <NUM> as needed so that a computer program fetched therefrom can be installed into the storage portion <NUM> as needed.

In the case that the foregoing series of processes are performed in software, a program constituting the software is installed from a network, e.g., the Internet, etc., or a storage medium, e.g., the removable medium <NUM>, etc..

Those skilled in the art shall appreciate that such a storage medium will not be limited to the removable medium <NUM> illustrated in <FIG> in which the program is stored and which is distributed separately from the device to provide a user with the program. Examples of the removable medium <NUM> include a magnetic disk (including a Floppy Disk (a registered trademark)), an optical disk (including Compact Disk-Read Only memory (CD-ROM) and a Digital Versatile Disk (DVD)), a magneto optical disk (including a Mini Disk (MD) (a registered trademark)) and a semiconductor memory. Alternatively the storage medium can be the ROM <NUM>, a hard disk included in the storage portion <NUM>, etc., in which the program is stored and which is distributed together with the apparatus including the same to the user.

It shall further be noted that the steps of the foregoing series of processes may naturally but not necessarily be performed in the sequential order as described chronically. Some of the steps may be performed concurrently or separately from each other.

Claim 1:
An electronic device for a user equipment (<NUM>) in a communication system (<NUM>), the communication system comprising a connection maintaining node (<NUM>), a source node (<NUM>), a target node (<NUM>) and the user equipment (<NUM>),
the electronic device comprising
circuitry (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), configured to
acquire a notification message comprising configuration information of the target node from the connection maintaining node, being a result of an admission control procedure performed by the target node;
release connection with the source node, and setup a connection with the target node based on the configuration information;
receive data which are transmitted by at least one of the connection maintaining node and the target node from the source node based on the result of the admission control procedure of the target node; wherein when the data are transmitted from the connection maintaining node, they are acceptable by the connection maintaining node; and wherein when the data are transmitted from the target node, they are acceptable by the target node; and
wherein the notification message comprises at least one of the following: which part of data related radio bearers of the user equipment that the connection maintaining node admits and which part of the data related radio bearers of the user equipment that the target node admits.