KR20140031991A - Releasing time domain measurement restrictions - Google Patents

Abstract

In some implementations, the method includes identifying a reestablishment with a subsequent eNB after losing a handover from the source eNodeB (eNB) or a connection with the initial eNB. The time domain measurement resource limit for the UE is identified. The time domain measurement resource restriction for the UE is released in connection with identifying handover or reestablishment.

Description

Releasing time domain measurement limits {RELEASING TIME DOMAIN MEASUREMENT RESTRICTIONS}

TECHNICAL FIELD The present invention relates to communication networks and, more particularly, to releasing time domain measurement restrictions.

Heterogeneous networks (HetNet) are networks comprising low power nodes and macro cells such as pico cells, femto cells and repeaters. Low power nodes or small cells are often overlaid on top of the macro cell, and it is also possible to share the same frequency. Such small cells can offload macro cells, improve indoor and cell edge performance, or provide other advantages. The 3GPP study for LET-Advanced (Release 10) includes a HetNet deployment as a major performance enhancement enabler. In HetNet deployment, inter cell interference coordination (ICIC) plays a key role, and time domain based resource sharing or coordination has been adopted as enhanced ICIC (eICIC), and eICIC is ABS (Almost Blank Subframe) ) Based solutions. LTE-Advanced (LET-A) identifies two major deployment scenarios in which eICIC is used. In a first or CSG (femto cell) scenario, the dominant interference condition may occur when the non-member user is very close to the CSG cell. In some cases, downlink transmissions from non-member CSG cells can significantly interfere with the Physical Downlink Control Channel (PDCCH). Interference to the PDCCH of the macro cell can have a detrimental effect on both uplink data transmission and downlink data transmission between the UE and the macro cell. In addition, downlink transmissions from non-member CSG cells can also interfere with other downlink control channels and reference signals, while other downlink control channels and reference signals can originate from macro cells and neighboring cells, cell measurement and wireless Can be used for link monitoring. Depending on network deployment and strategy, the system may not be able to convert users who are experiencing intercell interference to other E-UTRA carriers or other Radio Access Technology (RAT). Time domain ICIC may be used to allow such non-member UEs to continue to be served by the macro cell on the same frequency layer. Interference can be removed, minimized or reduced by the CSG cell using the Almost Blank Subframe (ABS) to protect the subframe of the corresponding macro cell from interference. The non-member UE signals to use the protected resource for radio resource measurement (RRM), radio link monitoring (RLM) and channel state information (CSI) measurements for the serving macro cell. This allows the UE to continue to be serviced by the macro cell under strong interference from the CSG cell.

In a second or pico cell scenario, time domain ICIC may be used for pico cell users, where the pico cell users are served on the edge of the serving pico cell as in the case of traffic offloading from the macro cell to the pico cell. Typically, downlink transmissions from macro cells can severely interfere with the PDCCH. In addition, downlink transmissions from macro cells may also interfere with reference signals and other downlink control channels from pico cells or neighboring pico cells. Other downlink control channels and reference signals can be used for cell measurement and radio link monitoring. Time domain ICIC may be used to allow such UEs to continue to be served by the pico cell on the same frequency layer. This interference can be reduced by the macro cell (s) using ABS to protect the subframe of the corresponding pico cell from interference. The UE served by the pico cell may use the protected resource for radio resource measurement (RRM), radio link monitoring (RLM) and channel state information (CSI) measurement for the serving pico cell.

For time domain ICIC, the use of subframes across different cells is temporally coordinated through so-called ABS pattern backhaul signaling or operations and management (OAM) configuration. In general, the ABS of the attacker cell is used to protect the resources of the subframe in the victim cell receiving strong intercell interference from the attacker cell. The ABS is a subframe with reduced transmit power (including no transmission) and / or reduced activity on some physical channels. The eNB ensures backward compatibility towards the UEs by transmitting system information as well as the necessary control channels and physical signals. A pattern based on ABS is signaled to the UE to limit the UE's measurement for a particular subframe, which is called time domain measurement resource limitation. Different patterns may be implemented depending on the type of cell being measured (serving cell or neighbor cell) and the type of measurement (eg RRM, RLM). In some cases, the macro eNB (attack) constructs an ABS pattern and passes it to the pico eNB (victim). The macro eNB does not schedule data transmissions in ABS subframes to protect the UEs served by the pico eNB at the edge of the pico cell. The pico eNB may schedule transmissions with the UEs of the cell center regardless of the ABS pattern. On the other hand, the pico eNB can schedule transmissions with UEs at the edge of the cell only in the ABS. The pico cell can configure the UE with three different measurement resource limits independently at the edge of the cell based on the received ABS pattern. The first limitation is for radio link monitoring (RLM) and RRM measurements for the PCell (in this case, the serving pico cell on the primary frequency). If configured, the RLM of the PCell is measured and performed only in the configured subframe. The second limitation is for the RRM measurement of neighboring cells on the primary frequency. If configured, the UE only measures neighbor cells in the configured subframe. This restriction may also include target neighbor cells to which the restriction is to be applied. The third limitation is for channel state estimation of the PCell. If configured, the UE can estimate CSI and CQI / PRM / RI only in the configured subframe.

In accordance with the current Radio Resource Control (RRC) protocol specification, MeasSubframePatternConfigNeigh is a Need ON information element (IE) in the EUTRA measurement object (measObjectEUTRA). The phrase "Need ON" means that in the absence of this element of information, the UE takes no action and, if applicable, continues to use the existing value (and / or associated function).

In some scenarios, in-frequency handover is to an area managed by an LTE-A system or an LTE system or Release 8 or 9 eNB without the eICIC / HetNet feature as opposed to an LTE-A system with support of the eICIC / HetNet feature. The UE can be switched. The target eNB prepares a handover command, but the target eNB does not support time domain measurement resource limitation. The target release 8 or 9 eNB cannot release this restriction in the prepared handover command or release it by the reconfiguration message after the handover without using the full configuration option and the measurement configuration by the preconfiguration option. All radio configurations, including the, are released. With the full configuration option, the size of the reconfiguration message is larger than without this option. Therefore, use of these options should be limited to maintain efficient operation. In addition, a target LTE-A eNB without eICIC / HetNet features may not instruct the UE to release measurement limits. The UE will then continue to apply this restriction because measSubframePatternConfigNeigh is not included in the handover command. In an in-frequency handover example, measurement resource limits for neighboring cells can be applied incoherently. That is, the UE applies the restriction but the eNB does not. This incoherent application may cause unintended handover or radio link failure due to differences in performance requirements (RSRP and RSRQ accuracy and detection time of neighbor cells) with or without measurement resource limitations for neighboring cells. With measurement resource limits, better signal-to-interference and noise to have the same Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ) accuracy than without these limits. Signal to interference and noise ratio (SINR) is required so that the measurement results reported by the UE applying this restriction may be less accurate than the eNB expects, which may cause unintended handovers. . In addition, using such measurement limits can take longer to detect cells in neighboring frequencies, which can cause radio link failure. The source eNB may perform measurement reconfiguration while preparing for handover with the target eNB. However, due to this additional processing, handover execution can be delayed, which results in a higher handover failure rate.

For the inter-frequency handover case, after the inter-frequency handover (f1 to f2), the time domain measurement resource limit configured for the primary frequency f1 of the source does not apply to f1 (after handover f1 Since it is no longer the primary frequency), it remains (ie is not released) unless explicitly done by the RRC Connection Reconfiguration message. Depending on the release of the target eNB or the support of the eICIC / HetNet feature, time domain measurement resource limits for neighboring cells may be applied incoherently. That is, the UE applies the restriction but the eNB does not. Such incoherent application can cause unintentional handover or radio link failure as described above.

In some scenarios, after the aforementioned handover (f1 to f2), subsequent inter-frequency handover (f2 to f1) is managed by a LET-A eNB or Release 8 or 9 eNB without eICIC / HetNet features. The UE to the desired area. The target eNB prepares a handover command. In this case, the target eNB does not support time domain measurement resource restriction. The target release 8 or 9 eNB cannot release this restriction in the prepared handover command or release it by the reconfiguration message after the handover without using the full configuration option and the measurement configuration by the preconfiguration option. All radio configurations, including the, are released. With the full configuration option, the size of the reconfiguration message is larger than without this option. Therefore, use of these options should be limited to maintain efficient operation. In addition, a target LTE-A eNB without eICIC / HetNet features may not instruct the UE to release measurement limits. The UE then restarts to apply the restriction on f1 upon handover. The problem is also applicable when the UE reestablishes an RRC connection. Time domain measurement resource limits for neighboring cells may be applied incoherently, which may cause another radio link failure or unintended handover.

In some scenarios, after experiencing a radio link failure, the UE may discover a suitable cell and re-establish the RRC connection in a cell controlled by a LET-A eNB or Release 8 or 9 eNB without eICIC / HetNet features. It can be established. In this case, subsequent eNBs do not support time domain measurement resource limits. Subsequent Release 8 or 9 eNBs may not indicate the release of this restriction by the reconfiguration message after the reestablishment without using the full configuration option, and all radio configurations including the measurement configuration are released by the preconfiguration option. With the full configuration option, the size of the reconfiguration message is larger than without this option. Therefore, use of these options should be limited to maintain efficient operation. In addition, subsequent LTE-A eNBs without eICIC / HetNet features may not instruct the UE to release measurement limits. The UE will then begin applying this restriction upon reestablishment. This problem applies regardless of the frequency of the cell in which the UE reestablishes the RRC connection.

In some scenarios, the UE reestablishes the RRC connection in the cell where the restriction no longer applies. The eNB releases this restriction by sending a reconfiguration message after the reestablishment procedure, but this message transmission is delayed due to overload on the eNB or this message does not reach the UE due to poor radio conditions. In the meantime, the UE restarts to apply this restriction. This problem applies regardless of the frequency of the cell in which the UE reestablishes the RRC connection.

It is an object of the present invention to provide a method and apparatus for releasing time domain measurement limitations.

In some implementations, the method includes identifying a reestablishment with a subsequent eNB after losing a handover from the source eNodeB (eNB) or a connection with the initial eNB. The time domain measurement resource limit for the UE is identified. The time domain measurement resource restriction for the UE is released in connection with identifying handover or reestablishment.

According to the present invention, it is possible to provide a method and apparatus for releasing time domain measurement constraints.

1 is an exemplary system for releasing time domain measurement constraints in accordance with some embodiments of the present disclosure.
2 is an exemplary LTE system of FIG.
3 illustrates an example UE of FIG. 1.
4 and 5 illustrate example methods for releasing time domain measurement constraints.
6 illustrates an example MobilityControlInfo information element including preserveMeasSubframePatternNeigh.
7 illustrates an example RRCConnectionReestablishment message including preserveMeasSubframePatternNeigh.
8 illustrates another example method for releasing time domain measurement constraints.
9 illustrates an example MeasObjectEUTRA information element.
10 illustrates an example HandoverPreparationInformation message.
11 is a flowchart illustrating another example method for releasing time domain measurement constraints.
12 is a flow diagram illustrating another example method for releasing a time domain measurement restriction.
Like reference symbols in the various drawings indicate like elements.

The present disclosure relates to a system and method for releasing time domain measurement resource limits in accordance with some embodiments of the present disclosure. For example, the UE may release time domain measurement resource restriction for neighbor cells upon handover or reestablishment. The UE may release the time domain measurement resource restriction for neighbor cells configured for the primary frequency of the source, the primary frequency of the target, or any EUTRA frequency. In general, in contrast to LTE-A systems with eICIC / HetNet features, LTE-A systems or LTE systems without eICIC / HetNet features include eNBs or legacy eNBs that do not support time domain measurement resource limitations. In order to eliminate the problems caused by eNBs without eICIC / HetNet features, measurement resource limits for neighboring cells configured for the primary frequency of the target are associated with UEs implementing these limits while the eNB does not support them. It can be released automatically to avoid. For example, the UE can identify handover or reestablishment and automatically set any time domain measurement resource limits configured for the target's primary frequency, for the source's primary frequency or for any EUTRA frequency. You can turn it off. By automatically releasing the limits configured for the primary frequency of the target, at least in response to handover or reestablishment, it is possible to minimize or reduce the impact of the preconfigured limits and to sufficiently avoid problems. This implementation is a simple solution and can be implemented independently of RRC signaling or without any change to RRC signaling. In addition, this solution can be implemented according to the Release 10 standard. After releasing the restriction, the target eNB can reestablish the restriction if the same restriction is needed in the target cell.

When the source eNB requests handover preparation from the target eNB, the source eNB indicates ue-ConfigRelease indicating RRC protocol release applicable to the current UE configuration. For example, if a UE with time domain measurement constraints is configured, ue-ConfigRelease is set to release 10. This information can be used by the target eNB to determine if the full configuration option should be used. If this field is not present, the target assumes that the current UE configuration is based on the Release 8 version of the RRC protocol. The overall configuration option includes the initialization of the radio configuration, which initializes the procedure independent of the configuration used for the source cell (s) except that the security algorithm continues during the RRC reestablishment. Since the size of the reconfiguration message with the full configuration options increases, its use must be limited to maintain efficient operation. Using the proposed automatic release of the measurement limit by the UE, even if a UE with time domain measurement limit is configured, the source eNB may move the ue-ConfigRelease to Release 8 or 9 to avoid full configuration by the target Release 8 or 9 eNB. Can be set. In the area of the network where time domain measurement constraints are used, the serving eNB can avoid using the more rewritten multi-antenna transmission technique defined in Release 10. Therefore, using the automatic release of the time domain measurement limit by the UE, the change to avoid the whole configuration in handover or reestablishment from the LTE-A system with the eICIC / HetNet feature to the LET system will be increased. Alternatively, the handover preparation request may be extended to indicate that no full reconfiguration is required, as shown in FIG. 10, and FIG. 10 illustrates an example andoverPreparationInformation message 1000.

In some implementations, the time domain measurement resource limit can be released for the neighbor cell by defining measSubframePatternConfigNeigh as "Need OR" in the MeasObjectEUTRA information element. The phrase "Need OR" means that if a message is received by the UE, in the absence of this information element, the UE can stop, stop using, delete or release any existing values. In other words, the UE may maintain the time domain measurement resource limit if the information element instructs the UE to maintain the limit. The absence of this information element may instruct the UE to release the time domain measurement resource restriction. To implement this solution, the RRC signaling definition of Release 10 can be updated.

In some implementations, the target eNB can indicate in the handover command whether the time domain measurement resource limit for the neighbor cell should be preserved. The preservation indication may be for a measurement object dedicated to the primary frequency of the target, a measurement object dedicated to the primary frequency of the source, or a measurement object of any EUTRA frequency. For example, if the same restriction is applicable in the target cell, preservation may be indicated for the target frequency, which may eliminate reconfiguring the restriction. This indication may be sent to the UE in an RRC Connection Reconfiguration message. If the UE receives the preservation indication in the reconfiguration message, the UE may maintain the measurement resource limit for the frequency specified by the preservation indication, and may release the measurement resource limit for other EUTRA frequencies. If no preservation indication is present, the UE may release time domain measurement resource restriction for neighbor cells configured for the target's primary frequency, source's primary frequency, or any EUTRA frequency. If the target eNB is Release 8 or 9, if there is no preservation indication, the UE may release the measurement restriction configured for the primary frequency of the target, the primary frequency of the source, or any EUTRA frequency. In the reestablishment procedure, the eNB dealing with the reestablishment indicates whether this restriction on the primary frequency of the target, the primary frequency of the source, or any EUTRA frequency should be preserved. If a previously configured restriction is applicable to the cell in which reestablishment occurs, an indication may be sent in an RRC Connection Reestablishment message.

In some implementations, the target LTE-A eNB without eICIC / HetNet feature instructs the UE to release the time domain measurement restriction if the UE with the restriction is configured by setting measSubframePatternConfigNeigh for release in the prepared handover command.

As described above, some implementations may include additional information elements to indicate whether a restriction should be preserved. Another solution may be that the source eNB adds the measurement configuration information element to the handover command prepared by the target eNB. For example, if explicit release of the measurement resource restriction is required, the source eNB may include this indication in the handover command prepared by the target eNB. The source eNB may acquire knowledge about the target eNB release information through the OAM system. Alternatively or additionally, the X2 interface may be extended to convey eNB release information.

 Referring to the environment description, FIG. 1 illustrates an example system 100 for releasing time domain measurement resource limits in connection with handover or reestablishment. For example, system 100 may release time domain measurement resource limits for a specified frequency, a predetermined frequency, or a preconfigured frequency in response to at least handover or reestablishment. As illustrated, the system 100 may be an LTE system without an eICIC / HetNet feature configured to communicate with a UE 106 or an LTE-A system (non-eICIC LTE system) 102 and an LTE system with an eICIC / HetNet feature ( eICIC LTE system) 104. The non-eICIC system 102 includes a base station 108a for wireless communication with the UE 106, where the base station 108a may have a signal coverage area partially indicated by the dashed line 110a. As mentioned above, the non-eICIC system 102 is not configured to enforce time domain measurement resource limits compared to LTE-A systems with eICIC / HetNet features, such as the eICIC system 104. The eICIC system 104 includes a base station 108b for wireless communication with the UE 106, where the base station 108b may have a signal coverage area partially indicated by the dashed line 110b. The eICIC system 104 is configured to implement time domain measurement resource limits using ABS. In some implementations, the UE 106 identifies a handover or reestablishment; Release the time domain measurement resource restriction in connection with handover or reestablishment; Automatically release time domain measurement resource limits in response to handover or reestablishment; Receive a message from the eICIC system 104 including information indicating to the UE 106 whether to release or maintain the time domain measurement resource restriction; One or more of lifting the restriction on at least one of the target's primary frequency, the source's primary frequency, the initial primary frequency, the subsequent primary frequency, or any EUTRAN frequency may be performed. By releasing the time domain restriction, incoherent application of the restrictions can be eliminated or reduced, which can improve mobility robustness by avoiding unintended handovers and radio link failures.

With a more detailed description of the elements, the non-eICIC system 102 communicates wirelessly using a base station 108a or an eNB 108a. In some implementations, non-eICIC system 102 can include a plurality of eNBs. In some implementations, the non-eICIC system 102 communicates with a network providing connectivity to other wireless and wired communication systems. The non-eICIC system 102 can communicate with the UE 106 using orthogonal frequency division multiplexing (OFDM) wireless technology. Similarly, eICIC system 104 includes an eNB 108b and communicates using OFDM. In addition, the eICIC system 104 may execute ABS (Almost Blank Subframe) to reduce intercell interference by temporally adjusting through backhaul signaling or operations and management (OAM) configuration. The eICIC system 104 may use ABS in the attacker cell to protect the resources of the subframe in the victim cell receiving strong intercell interference from the attacker cell. As mentioned above, an ABS is a subframe with reduced transmit power (including no transmission) and / or reduced activity on some physical channels. The eNB 108b may signal patterns based on ABS to the UE 106 to limit the UE's measurement for a particular subframe, which is called time domain measurement resource limitation. Different patterns may be implemented depending on the type of cell being measured (serving cell or neighbor cell) and the type of measurement (eg RRM, RLM).

In general, UE 106 may receive and transmit wireless and / or contactless communication signals in system 100. As used in the present disclosure, the UE 106 may be a cellular phone, data phone, pager, portable computer, SIP phone, smart phone, personal digital assistant (PDA), digital camera, MP3 player, camcorder, these devices or It is intended to include one or more processors in other devices, or any other suitable processing devices capable of communicating information with the LTE system 102 and the LTE-A system 104. In some implementations, the UE 106 can be based on cellular wireless technology. For example, UE 106 may be a PDA operable to wirelessly connect with an external or insecure network. In another example, the UE 106 may be an input device, such as a keypad, touch screen, mouse, or other device capable of receiving information, and digital data, visual information, or a graphical user interface (GUI) 112. And a smartphone including an output device capable of conveying information associated with the LTE system 102 and the LTE-A system 104.

GUI 112 is a graphical user operable to allow a user of UE 106 to interface with at least a portion of system 100 for any suitable purpose (eg, authorizing to indicate enablement of alert notification). Contains interfaces. In general, the GUI 112 provides a specific user with an efficient and user friendly representation of the data provided by or communicated within the system 100 and / or the access service and self provided by the PLMN 102. Provides an efficient and user friendly means for users to manage settings. GUI 112 may include a plurality of custom frames or views with interactive fields, pull-down lists, and / or buttons operated by a user. The term graphical user interface may be used in the singular or plural to describe each of the one or more graphical user interfaces and the displays of a particular graphical user interface. GUI 112 may include any graphical user interface, such as a general web browser or touch screen that processes information of system 100 and displays the results to a user.

Referring to FIG. 2, LTE network 200 includes a core network called an Evolved Packet Core (EPC) and an LTE radio access network (eg, an evolved UTRAN (E-UTRAN)). The core network provides access to an external network, such as the internet 230. LTE network 200 includes one or more base stations, such as eNodeB (eNB) base stations 210a and 210b, which provide wireless service (s) to one or more devices, such as UE 205.

The EPC-based core network may include a Serving Gateway (SGW) 220, a Mobility Management Entity (MME) 215, and a Packet Gateway (PGW) 225. SGW 220 may route traffic within the core network. The MME 215 is responsible for core network mobility control attachment of the UE 205 to the core network 205 and for maintaining contact with idle mode UEs. PGW 225 is responsible for enabling input / output of traffic to and from the Internet 230. PGW 225 may assign IP addresses to UEs 205.

An LTE based wireless communication system has a network interface defined between system elements. The network interface is defined as Uu interface defined between UE and eNB, S1U user plane interface defined between eNB and SGW, S1C control plane interface defined between eNB and MME (also known as S1-MME), and defined between SGW and PGW Includes a S5 / S8 interface. Note that the combination of S1U and S1C is usually simplified to "S1".

3 illustrates an example UE 305 that includes a processor electronic device 310 such as a processor that implements one or more of the techniques presented herein. The UE 305 may include a transceiver electronic device 315 to send and receive wireless signals over one or more communication interfaces, such as one or more antennas 320. The UE 305 may include other communication interfaces for transmitting and receiving data. In some implementations, the UE 305 can include one or more wired network interfaces to communicate with the wired network. In other implementations, the UE 305 can input / output (I / I) of user data (eg, text input from a keyboard, graphical output to a display, touch screen input, vibrator, accelerometer, test port, or debug port). One or more data interfaces 330 for O). The UE 305 may include one or more memories 340 configured to store information such as data and / or instructions. In still other implementations, the processor electronic device 310 can include at least a portion of the transceiver electronic device 315.

4, 5, and 8 are flow diagrams illustrating example methods 400, 500, and 800 for releasing time domain measurement resource limits. The illustrated methods 400, 500, and 800 are described with respect to the system 100 of FIG. 1, but this method may be used by any other suitable system. Moreover, system 100 may use any other suitable technique for performing these tasks. Thus, many of the steps in this flowchart may occur simultaneously and / or in a different order than the one shown. As long as the methods remain appropriate, the system 100 may also use methods with additional steps, fewer steps, and / or different steps. In addition, the system 100 may have settings based on other granularities without departing from the scope of the present disclosure.

4, a method 400 is a flowchart for automatically releasing time domain measurement resource limits in response to handover or reestablishment. For the E-UTRAN executing the handover, a measObjectId corresponding to the primary frequency of each handover target is configured. For the E-UTRAN executing the reestablishment, a measObjectId corresponding to the primary frequency of each handover target is configured and subsequent connection reconfiguration procedure immediately follows the reestablishment.

The method 400 begins at step 402, where the UE 106 identifies each measId included in the measIdList in VarMeasConfig. At decision step 404, if triggerType is set periodically, at step 406, UE 106 removes this measId from measIdList in VarMeasConfig. Otherwise, execution proceeds to step 408, where the UE releases MeasSubframePatternConfigNeigh if MeasSubframePatternConfigNeigh is configured in measObject for the primary frequency of the target. If the procedure was triggered due to a handover or successful reestablishment, and in decision step 410, if the process includes a change in the primary frequency, then in step 412, the UE 106 updates the measId value in the measIdList in VarMeasConfig. do. In decision step 414, if there is a measObjectId value corresponding to the primary frequency of the target, then in step 416, if the measId value is linked to the measObjectId value corresponding to the primary frequency of the source, this measId value is determined by the target's primary frequency. Linked to the measObjectId value corresponding to the primary frequency. In step 418, if the measId value is linked to a measObjectId value corresponding to the primary frequency of the target, this measId value is linked to a measObjectId value corresponding to the primary frequency of the source. Returning to decision step 414, if there is no measObjectId value corresponding to the primary frequency of the target, then at step 420, all measId values linked to the measObjectId value corresponding to the primary frequency of the source are removed. In step 422, the UE 106 removes all measurement report entries in VarMeasReportList. Next, at step 424, the UE 106 stops the periodic reporting timer or timer T321 (which timer is running) as well as associated information for all measIds (eg, timeToTrigger). In step 426, the UE 106 releases the measurement gap if the measurement gap has been activated. If the UE requires a measurement gap to perform an inter-frequency measurement or an inter-RAT measurement, the UE may resume the inter-frequency measurement and the inter-RAT measurement after the E-UTRAN sets up the measurement gap.

Referring to FIG. 11, a method 1100 is a flow chart for handover preparation by an eICIC LTE eNB 104 as a source eNB. The method 1100 begins at step 1102, where the source eNB 104 selects a target eNB to which the UE 106 is switched. In step 1104, the source eNB 104 generates a handover preparation command shown in FIG. 10. In step 1106, if a UE is configured that does not have any Release 10 features except for time domain measurement restrictions, the source eNB releases the features configured in the UE 106 to prevent the target eNB from applying the full configuration option. Set ue-ConfigRelease (1002 in FIG. 10) to Release 8 or 9 according to this. If only Release 8 features are configured, except for time domain measurement restrictions, then ue-ConfigRelease may not be included. Source eNB 104 may also set FullConfig (1004 in FIG. 10) to FALSE to prevent the target eNB from applying the full configuration option. If the UE with the Release 10 feature is configured with the exception of the time domain measurement restriction at step 1106, then at step 1110 the source eNB sets the ue-ConfigRelease to Release 10. In step 1112, the source eNB 104 sends a handover ready command to the target eNB. The method can be applied to other Release 10 features other than time domain measurement limitations.

5, a method 500 is a flow chart for releasing time domain measurement resource constraints when retention instructions are omitted from communication in connection with handover or reestablishment. For example, measurement resource limits for neighboring cells may be released by the UE 106 upon handover or reestablishment if its conservation is not indicated, as shown below. For the E-UTRAN executing the handover, a measObjectId corresponding to the primary frequency of each handover target is configured. For the E-UTRAN executing the reestablishment, a measObjectId corresponding to the primary frequency of each handover target is configured and the subsequent connection reconfiguration procedure immediately follows the reestablishment.

The method 500 begins at step 502, where the UE 106 identifies each measId included in the measIdList in VarMeasConfig. In decision step 504, if the triggerType is set periodically, in step 506 the UE 106 removes measId from the measIdList in VarMeasConfig. Otherwise, execution proceeds to decision step 508. If PreserveMeasSubframePatternNeigh is not included, in step 510, UE 106 releases MeasSubframePatternConfigNeigh if MeasSubframePatternConfigNeigh is configured in measObject for the primary frequency of the target, for the primary frequency of the source, or for any EUTRA frequency. do. If PreserveMeasSubframePatternNeigh is included, at step 512, UE 106 releases MeasSubframePatternConfigNeigh if MeasSubframePatternConfigNeigh is configured in measObject for frequencies not indicated by PreserveMeasSubframePatternNeigh. With regard to handover, FIG. 6 illustrates an exemplary MobilityControlInfo information element 600 that includes preserveMeasSubframePatternNeigh. This field is used to indicate the frequency at which measSubframePatternConfigNeigh should be maintained during handover. SOURCE means to preserve the restriction on the source's primary frequency, TARGET means to preserve the limitation on the target's primary frequency, and ANY means to preserve the limitation on any EUTRA frequency. With regard to reestablishment, FIG. 7 illustrates an example RRCConnectionReestablishment message 700 that includes preserveMeasSubframePatternNeigh. This field is used only to indicate the frequency at which measSubframePatternConfigNeigh should be maintained upon reestablishment. SOURCE means to preserve the restriction on the source's primary frequency, TARGET means to preserve the limitation on the target's primary frequency, and ANY means to preserve the limitation on any EUTRA frequency. If the procedure was triggered due to a handover or successful reestablishment and the process included a change in the primary frequency at decision step 514, then at step 516, the UE 106 updates the measId value in the measIdList in VarMeasConfig. In decision step 518, if there is a measObjectId value corresponding to the primary frequency of the target, then in step 520, if the measId value is linked to a measObjectId value corresponding to the primary frequency of the source, this measId value is determined by the target's primary frequency. Linked to the measObjectId value corresponding to the primary frequency. In step 522, if the measId value is linked to a measObjectId value corresponding to the primary frequency of the target, this measId value is linked to a measObjectId value corresponding to the primary frequency of the source. Returning to decision step 518, if there is no measObjectId value corresponding to the primary frequency of the target, then at step 524 all measId values linked to the measObjectId value corresponding to the primary frequency of the source are removed.

Referring to FIG. 8, method 800 relates to redefining the current information element or measSubframePatternConfigNeigh such that time domain measurement resource limits are released when no explicit signaling is received in connection with handover or reestablishment. Currently, measSubframePatternConfigNeigh is defined as OPTIONAL-Need ON, so an explicit release is required to stop this application. The method 800 changes its value from Need ON to Need OR such that the configured measSubframePatternConfigNeigh is released if no explicit signaling is received upon handover or reestablishment. An example of measSubframePatternConfigNeigh, which is an exemplary MeasObjectEUTRA information element that includes the value of Need OR, is shown in FIG. 9.

The method 800 begins at step 802 and identifies each measObjectId included in the received measObjectToAddModList. In decision step 804, if an entry with a matching measObjectId exists in the measObjectList in VarMeasConfig, then in step 806, the UE 106 receives for measObject except for the cellsToAddModList, blackCellsToAddModList, cellsToRemoveList, blackCellsToRemoveList, and measSubframePatternConfigNeigh fields. Can replace that entry with the new value. If measSubframePatternConfigNeigh is configured in a measObject with a matching measObjectId and the received measObject does not contain measSubframePatternConfigNeigh, the configured measurement constraints will be released. In decision step 808, if the received measObject includes cellsToRemoveList, then in step 810, for each cellIndex included in cellsToRemoveList, the UE 106 removes the entry with the matching cellIndex from cellsToAddModList. Otherwise, execution proceeds to decision step 812. If the received measObject contains cellsToAddModList, for each cellIndex value contained in cellsToAddModList, at step 814, UE 106 returns the received value for this cellIndex if an entry with a matching cellIndex exists in cellsToAddModList. Replace that entry. Otherwise, at step 816, the UE 106 adds a new entry for the received cellIndex to cellsToAddModList. In decision step 818, if the received measObject includes blackCellsToRemoveList, for each cellIndex included in blackCellsToRemoveList, in step 820, UE 106 removes the entry with the matching cellIndex from blackCellsToAddModList. Otherwise, execution proceeds to decision step 822. If the received measObject contains blackCellsToAddModList, for each cellIndex included in blackCellsToAddModList, in step 824, the UE 106 receives the entry with the value received for cellIndex if the entry with the matching cellIndex is included in blackCellsToAddModList. Replace. If not, in step 826, UE 106 adds a new entry for the received cellIndex to blackCellsToAddModList. In step 832, for each measId associated with measObjectId in measIdList in VarMeasConfig, if any, UE 106 removes the measurement report entry for measId from VarMeasReportList, if included. Next, at step 834, the UE 106 stops the periodic reporting timer or timer T321 (which timer is running) and resets the associated information (eg, timeToTrigger) for the measId. Returning to decision step 804, if a matching measObjectId is not present in the measObjectList in VarMeasConfig, then at step 836, the UE 106 adds a new entry for the received measObject to the measObjectList in VarMeasConfig.

Referring to FIG. 12, method 1200 is a flowchart for handover preparation by an LTE-A non-ICIC eNB 102 as a target eNB. In step 1202, the target eNB 102 receives a handover preparation command shown in FIG. 10 from the source eNB. In step 1204, the target eNB 102 reserves a radio resource for the UE 106 and generates a handover command. In step 1206, if the UE 106 with time domain measurement constraints is configured, in step 1208, the target eNB 102 determines the primary frequency of the target, the primary frequency of the source, or any EUTRA frequency. Set measSubframePatternConfigNeigh to release from measObject. In step 1210, the target eNB 102 sends a handover command back to the source eNB. The method may be applied to Release 10 features not supported by the LTE-A target eNB other than the time domain measurement restriction.

A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, if the source eNB knows that the target eNB is Release 8/9, the source eNB limits the measurement resource by adding measurement configuration information elements to the handover command prepared by the target eNB before sending the handover command to the UE. Can be released. Accordingly, other embodiments are within the scope of the following claims.

Claims (41)

In the method,
Identifying a restablishment with a subsequent eNB after losing handover or connection with the initial eNB from the source eNodeB (eNB);
Identifying a time domain measurement resource limit for the UE; And
Releasing time domain measurement resource restriction for the UE in connection with identifying the handover or reestablishment
≪ / RTI > 2. The method of claim 1, wherein releasing the time domain measurement resource limit comprises automatically releasing the time domain measurement resource limit in response to the handover or reestablishment. The method of claim 1, wherein releasing the time domain measurement resource restriction,
Receiving wireless communication in connection with the handover or reestablishment; And
Determining that the wireless communication is omitting a parameter instructing the UE to maintain the time domain measurement resource limit. 4. The method of claim 3 wherein the wireless communication is an EUTRAN measurement object and the parameter includes a preserveMeasSubframePatternNeigh information element (IE) in the EUTRAN measurement object. 4. The method of claim 3 wherein the wireless communication is an RRC Connection Reconfiguration message and the parameter includes a preservation indication in the RRC Connection Reconfiguration message. 4. The method of claim 3, wherein the wireless communication is an RRC Connection Reestablishment message from a secondary eNB and the parameter includes a retention indication in the RRC Connection Reestablishment message. 2. The method of claim 1, wherein releasing the time domain measurement resource restriction comprises: primary frequency of target, primary frequency of source, initial primary frequency, subsequent primary frequency, any EUTRA frequency, or predetermined or Releasing time domain measurement resource restriction for neighboring cells for at least one of the preconfigured frequencies. In User Equipment (UE),
One or more processors, wherein the one or more processors include:
Identify a reestablishment with a subsequent eNB after losing handover or connection with the initial eNB from the source eNodeB (eNB);
Identify a time domain measurement resource limit for the UE;
And release the time domain measurement resource restriction for the UE in connection with identifying the handover or reestablishment. 9. The user of claim 8, wherein the one or more processors configured to release the time domain measurement resource limit includes one or more processors configured to automatically release the time domain measurement resource limit in response to the handover or reestablishment. Equipment (UE). 10. The system of claim 8, wherein the one or more processors configured to release the time domain measurement resource limit comprises:
Receive wireless communication in connection with the handover or reestablishment;
And one or more processors configured to determine that the wireless communication is omitting a parameter instructing the UE to maintain the time domain measurement resource limit. 11. The UE of claim 10 wherein the wireless communication is an EUTRAN measurement object and the parameter comprises a preserveMeasSubframePatternNeigh information element (IE) in the EUTRAN measurement object. 11. The UE of claim 10 wherein the wireless communication is an RRC Connection Reconfiguration message and the parameter comprises a preservation indication in the RRC Connection Reconfiguration message. 12. The UE of claim 10 wherein the wireless communication is an RRC Connection Reestablishment message from a secondary eNB and the parameter includes a retention indication in the RRC Connection Reestablishment message. 10. The system of claim 8, wherein the one or more processors configured to release the time domain measurement resource constraints comprise: a primary frequency of a target, a primary frequency of a source, an initial primary frequency, a subsequent primary frequency, any EUTRA frequency, or And one or more processors configured to release time domain measurement resource limits for neighboring cells for at least one of a predetermined or preconfigured frequency. A computer readable storage medium encoded with a computer program product, the computer program product comprising:
Identify a reestablishment with a subsequent eNB after losing handover or connection with the initial eNB from the source eNodeB (eNB);
Identify a time domain measurement resource limit for the UE;
Releasing time domain measurement resource restriction for the UE in connection with identifying the handover or reestablishment
And computer readable instructions to cause at least one processor to perform an operation comprising a computer readable medium. 16. The computer of claim 15, wherein the act of releasing the time domain measured resource limit comprises an act of automatically releasing the time domain measured resource limit in response to the handover or reestablishment. Readable Storage Media. 16. The method of claim 15, wherein the act comprising releasing the time domain measurement resource limit comprises:
Receive wireless communication in connection with the handover or reestablishment;
And determining that the wireless communication is omitting a parameter that instructs the UE to maintain the time domain measurement resource limit. 18. The computer readable storage medium of claim 17, wherein the wireless communication is an EUTRAN measurement object and the parameter comprises a preserveMeasSubframePatternNeigh information element (IE) in the EUTRAN measurement object. 18. The computer readable storage medium of claim 17, wherein the wireless communication is an RRC Connection Reconfiguration message, and wherein the parameter comprises a preservation indication in the RRC Connection Reconfiguration message. 18. The computer readable storage medium of claim 17, wherein the wireless communication is an RRC Connection Reestablishment message from a secondary eNB and the parameter includes a retention indication in the RRC Connection Reestablishment message. 16. The method of claim 15, wherein the act of releasing the time domain measurement resource restriction comprises: a primary frequency of a target, a primary frequency of a source, an initial primary frequency, a subsequent primary frequency, any EUTRA frequency, or And releasing time domain measurement resource limits for neighboring cells for at least one of a predetermined or preconfigured frequency. In the method,
Identifying, by the source eNB, a handover to the target eNB;
Identifying a time domain measurement resource limit for the UE; And
Sending a message to the UE to maintain a time domain measurement resource limit for the UE based on the handover or reestablishment
≪ / RTI > 23. The method of claim 22,
Receiving a handover command from the target eNB;
Updating the handover command using a measSubframePatternConfigNeigh information element (IE) instructing to maintain the time domain measurement resource limit,
The sent message comprises an RRC Connection Reconfiguration message containing the updated handover command. 23. The method of claim 22,
Sending a request to the target eNB for information identifying a type of network; And
Based on the response from the target eNB, determining that the target eNB is served by an LTE network. 25. The method of claim 24, wherein the request is sent using an X2 interface or an operations and management (OAM) system. 23. The method of claim 22, wherein the message indicates to maintain time domain measurement resource limits for neighboring cells for at least one of a target's primary frequency, source's primary frequency, or any EUTRA frequency. 24. The method of claim 23, wherein the received handover command comprises a measSubframePatternConfigNeigh information element (IE) set by the target eNB to release a primary frequency of a target, a primary frequency of a source, or any EUTRA frequency. ,
The method comprises:
Sending the handover command to the UE. In the eNB,
At least one processor, wherein the at least one processor,
Identify a handover to the target eNB;
Identify a time domain measurement resource limit for the UE;
And send a message to the UE to maintain a time domain measurement resource limit for the UE based on the handover or reestablishment. The processor of claim 28, wherein the processor is further configured to:
Receive a handover command from the target eNB;
Update the handover command using a measSubframePatternConfigNeigh information element (IE) indicating to maintain the time domain measurement resource limit,
The sent message comprises an RRC Connection Reconfiguration message including the updated handover command. The processor of claim 28, wherein the processor is further configured to:
Send a request to the target eNB for information identifying the type of network;
Based on the response from the target eNB, the target eNB is configured to determine to be served by an LTE network. 31. The eNB of claim 30 wherein the request is sent using an X2 interface or an operation and management (OAM) system. 29. The eNB of claim 28 wherein the message indicates to maintain time domain measurement resource limits for neighboring cells for at least one of a target's primary frequency, source's primary frequency, or any EUTRA frequency. 30. The method of claim 29, wherein the received handover command comprises a measSubframePatternConfigNeigh information element (IE) set by the target eNB to release a primary frequency of a target, a primary frequency of a source, or any EUTRA frequency. ,
The one or more processors may further comprise:
And transmit the handover command to the UE. A computer readable storage medium encoded with a computer program product, the computer program product comprising:
Identify, by the source eNB, the handover to the target eNB;
Identify a time domain measurement resource limit for the UE;
Sending a message to the UE to maintain a time domain measurement resource limit for the UE based on the handover or reestablishment
And computer readable instructions to cause at least one processor to perform an operation comprising a computer readable medium. The method of claim 34, wherein the command is:
Receive a handover command from the target eNB;
Updating the handover command using a measSubframePatternConfigNeigh information element (IE) instructing to maintain the time domain measurement resource limit,
And wherein the transmitted message comprises an RRC Connection Reconfiguration message containing the updated handover command. The method of claim 34, wherein the command is:
Send a request to the target eNB for information identifying the type of network;
And determining that the target eNB is serviced by an LTE network based on a response from the target eNB. 37. The computer readable storage medium of claim 36, wherein the request is transmitted using an X2 interface or an operating and management (OAM) system. 35. The computer readable medium of claim 34, wherein the message indicates to maintain time domain measurement resource limits for neighboring cells for at least one of a target's primary frequency, source's primary frequency, or any EUTRA frequency. Storage media. 36. The method of claim 35, wherein the received handover command comprises a measSubframePatternConfigNeigh information element (IE) set by the target eNB to release a primary frequency of a target, a primary frequency of a source, or any EUTRA frequency. ,
Wherein the command comprises:
And sending the handover command to the UE. In the method,
Identifying, by the source eNB, a handover to the target eNB;
Identifying a feature configured for the UE; And
sending a HandoverPreparationInformation message with no ue-ConfigRelease or with a ue-ConfigRelease set to Release 8 or 9 to the target eNB
≪ / RTI > 41. The method of claim 40, wherein the feature comprises time domain measurement resource limitation.

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