JP2010193456A - Method and apparatus for measurement with respect to handover in mobile communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for measurement with respect to handover in mobile communications. <P>SOLUTION: The method includes: determining a first object set which includes one or a plurality of measurement objects; assigning a plurality of unit measurement time periods (Tunit) to respective measurement objects in the first object set in turn; excluding one or a plurality of measurement objects from the first object set to obtain second object set, wherein the unit measurement time periods of the excluded measurement objects are reassigned to the measurement objects of the second object set; measuring signal intensity of each measurement object in the second object set based on the correspondence relationship between the unit measurement time periods obtained by the reassignment and the measurement objects in the second object set; and transmitting a measurement report based on the monitored situation of a measurement-report trigger event. Based on the method and apparatus, accuracy and timeliness of the measurement result can be assured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to user handover in a mobile communication system, and more particularly to a handover measurement method and apparatus in mobile communication.

  Cellular mobile phones bring tremendous convenience to people's communication, and the second generation Global System for Mobile Communication (GSM) adopts digital communication to further improve the call quality of mobile communication. The 3rd Generation Partnership Project (3GPP), as an important organization in the mobile communication field, greatly promotes the standardization of the 3rd generation mobile communication technology (3G: The Third Generation), and wideband code division Multiple access (WCDMA: Wide Speed Multiple Access), high-speed downlink packet access (HSDPA: High Speed Downlink Packet Access), and high-speed uplink packet access (HSUPA: High Speed Upcc) Was enacted.

  In order to meet the challenges of broadband access technology and meet the increasing demand for new services, 3GPP has started standardization work for 3G Long Term Evolution (LTE) technology from the end of 2004 As a result, the spectrum efficiency is further improved, the performance of the cell edge user is improved, the system delay is reduced, and a higher speed access service is provided to a high speed mobile user. Future LTE-A technology will further increase the spectrum bandwidth several times, double the data rate based on LTE, and provide more mobile users with higher speed and better performance I will provide a.

  In the mobile communication system described above, management of user mobility in the connected state (CONNECTED) is particularly important. In order to realize management of user mobility in the connected state, a handover is defined in the mobile communication system, and a user in the connected state is allowed to be handed over to another cell if certain conditions are met. The If there is no handover, when the user leaves the serving cell, a new cell may be re-accessed after the call drop, which greatly affects the user's service satisfaction.

  In general, handover includes three main processes: measurement, handover determination, and handover execution. FIG. 1 is a flowchart of handover in a conventional method, which includes the following steps.

  In steps 101 to 103, after receiving the measurement setting provided from the serving base station, the user measures a reference signal received power (RSRP) between the serving cell and the neighboring cell, and satisfies a certain condition. If so, send a measurement report to the serving base station.

  In steps 104 to 105, the serving base station determines whether to perform handover based on the received measurement report. If it determines to perform handover, the serving base station determines one target base station based on the signal strength of each neighboring cell in the measurement report. And notifies the user to hand over to the target base station.

  In steps 106 to 107, after receiving the handover command from the serving base station, the user leaves the serving base station, synchronizes with the target base station, and accesses the target base station.

  As can be seen from the above handover process, the accuracy of the measurement report is particularly important for the handover. If the measurement report is not accurate, one target base station with poor channel conditions will be selected by the serving base station. In this way, after the user has handed over to the target base station, a ping-pong effect occurs, which may result in a call drop, which greatly affects the service quality of the user.

  Considering the difference in carrier frequency and access technology between the target base station and the serving base station, the handover is classified into three types: the same frequency handover, the inter-frequency handover, and the inter-system handover. In the overlay network shown in FIG. 2, various wireless access methods coexist.

  When the target base station and the serving base station belong to the same carrier frequency of the same radio access system, the handover is the same frequency handover. For example, if both the target base station and the serving base station are located in the LTE-A 3.4G layer (that is, the indoor hot spot cover), they belong to the same frequency handover. If the target base station and the serving base station belong to the same system, but belong to different carrier frequencies, the handover is an inter-frequency handover. For example, when the serving base station is located in the LTE-A 3.4G layer and the target base station is located in the LTE-A 2.5G layer, it belongs to the inter-frequency handover. When the target base station and the serving base station belong to different radio access systems, the handover is an inter-system handover. For example, when the serving base station is located in the LTE-A 800M layer and the target base station is located in the WCDMA layer, it belongs to the inter-system handover.

  As shown in Table 1, different types of measurements need to be employed for different handovers.

  In the case of the same frequency handover, since the target base station and the serving base station are on the same carrier frequency, the user can connect to the serving base station and monitor the signal strength of the target base station. Need only be measured, and need not be assisted by a specific measurement time (gap).

  In the case of inter-frequency handover and inter-system handover, it is necessary to employ different frequency measurement. When measuring the signal strength of the target base station, the user can monitor the signal strength only after synchronizing with the carrier frequency of the target base station. At this time, the user cannot communicate with the serving base station. As can be seen, different frequency measurements need to be assisted by a specific measurement gap.

  In the conventional technique, the measurement shown in steps 101 to 103 in FIG. 1 specifically includes the following.

  1. After the user establishes a connection with the serving base station, the serving base station performs measurement settings for the user. The measurement setting mainly includes, for example, setting measurement parameters such as a measurement target, a measurement time (gap), a measurement report trigger event, and a measurement report observation time (Ttrig).

  The measurement target refers to another frequency or another system that covers the user's location, for example, frequency 1 (F1) or frequency 2 (F2), or WCDMA or GSM.

  Regarding the measurement gap, two types of formats are shown in the 3GPP technical standards. Here, the length of the measurement gap is set to 6 ms, but the repetition period of the measurement gap is 40 ms and 80 ms, respectively. In addition, in order to obtain a relatively accurate measurement result, one measurement value can be obtained for one measurement object (for example, F2) only after a unit measurement time period (Tunit) has elapsed. The unit measurement time zone includes a plurality of continuous measurement gaps. In other words, when the user assigns the measurement gap, the user actually assigns the measurement gap to the measurement target in units of units. For example, a plurality of continuous measurement gaps in a certain unit are all assigned to the same measurement object, and a plurality of continuous measurement gaps in the next unit are assigned to other measurement objects. In general, when the unit measurement time zone is 480 ms and the repetition period of the measurement gap is 80 ms, the unit includes six measurement gaps of 6 ms, and other times other than the measurement gap remain unchanged. Used for communication with base stations.

  Ttrig is an observation period. If a predefined measurement report trigger event has been satisfied throughout the observation period, after the observation period ends, the user sends a measurement report. The range of the value of Ttrig is 0 to 5 s. Here, it is assumed that the value of Ttrig is 2.4 s, that is, five 480 ms.

  2. After receiving the measurement setting, the user monitors the signal strength of the measurement object within a unit measurement time zone of a measurement object (for example, F2), and the measurement object is, for example, event A3 (Event A3) If it finds that an event is met, it starts timing.

  3. If the duration that F2 satisfies Event A3 exceeds Ttrig, the user sends a measurement report to the serving base station. The measurement report is attached with information (for example, a cell number, a signal strength value, etc.) related to a cell that satisfies Event A3 in F2.

  Specifically, Event A3 is defined as the RSRP of the neighboring cell being one offset amount larger than the serving cell, as shown in inequality (1).

Mn + Ofn + Ocn-Hys> Ms + Ofs + Ocs + Off (1)
Here, Mn is the measurement result of the adjacent cell, Ofn is the frequency offset amount of the adjacent frequency, Okn is the cell offset amount of the adjacent cell, Hys is the hysteresis coefficient, and Ms is the measurement result of the serving cell. , Ofs is the frequency offset amount of the service frequency, Ocs is the cell offset amount of the serving cell, and Off is the event offset amount. In inequality (1), Mn, Ms and Off are three relatively major parameters.

  In the standard, when it is necessary to measure a plurality of measurement objects of different frequencies or different systems, the measurement cycle is Nobject × 480 ms because the measurement is performed on a plurality of measurement objects, and Nobject is a measurement object. Indicates that it is a number. Since multiple measurement objects are measured with a ring number, each measurement object can be measured for the next time only after one measurement is performed and after all other measurement objects have been measured. it can. Thus, there are cases as follows.

[Case 1]
As shown in FIG. 3, it is assumed that a certain measurement target (for example, F2) has actually been able to satisfy Event A3 at time t0. However, according to the conventional measurement mechanism, both the time t0 and the next unit measurement time zone are for measurement with respect to other measurement objects, and for the measurement with respect to F2 only after the time t1 is reached. The unit measurement time zone starts. That is, the user can discover that F2 has already satisfied Event A3 only after waiting until time t1, and starts Ttrig timing for F2 at time t1. Hereinafter, the delay from t0 to t1 is referred to as a Ttrig delay.

  In the Ttrig period, when the user measures that F2 always satisfies Event A3 in the unit measurement time zone assigned to F2, the user transmits information on the cell that satisfies Event A3 in F2 to the serving base station after the end of Ttrig. Hereinafter, the delay from t0 to t2 is referred to as a measurement report (MR) delay. The MR delay is composed of a Ttrig delay and a Ttrig. If Ttrig is a fixed value, the MR delay is mainly determined by the Ttrig delay. After receiving the measurement report, the serving base station selects a target base station and sends a handover command to the user.

  As can be seen from this, if there is no Ttrig delay, the user may have already performed a handover at time (t1 + Δt), and at this time, the channel quality of the serving base station is still very bad. Not. However, since there is a Ttrig delay, the user handover is delayed until time t3, and at this time, the channel quality of the serving base station has a great influence on the communication quality, and thus may have deteriorated so as to cause a call drop. The influence of such delay is shown in Table 2.

[Case 2]
After F2 is monitored to meet EventA3, the user starts Ttrig timing. When all the measurement results of F2 obtained in the Ttrig period satisfy EventA3, the user transmits a measurement report related to F2, that is, MR (F2) after the end of Ttrig. As shown in FIG. 4, since there are a plurality of measurement objects and a plurality of measurement objects are measured by the rotation number even in the Ttrig period, the user can measure only one unit for measurement in the Ttrig period. It is only possible to assign to a target (for example, F2) and transmit the measurement result in the unit as a measurement report to the serving base station. If the change state between F2 and the service frequency F0 is as shown in FIG. 5 and FIG. 6, only one-time sampling or high-speed fading affects the received signal quality. The real situation cannot be adequately reflected, and it is more likely that the wrong measurement report will be provided to the serving base station, eventually the serving base station selects the wrong target base station and the user gets the wrong target It is clear that ping-pong, instantaneous re-handover, and hence call drop will occur when accessing the base station.

[Case 3]
As shown in FIG. 7, it is possible that a plurality of frequencies trigger the Ttrig timing almost simultaneously. Since it is monitored that F2 satisfies EventA3 at time t1, the user starts measuring Ttrig. This Ttrig is referred to as Ttrig2. As shown in FIG. 8, before the end of Ttrig2, and since F1 is monitored to satisfy Event A3, the user starts measuring Ttrig. This Ttrig is referred to as Ttrig1. The time lengths of Ttrig1 and Ttrig2 are the same. As can be seen from this, in the time zone from t2 to t3, there are two Ttrigs being counted, where Ttrig2 corresponds to F2 and Ttrig1 corresponds to F1. If F2 and F1 monitored by the user satisfy EventA3 over the Ttrig period after Ttrig2 and Ttrig1 have ended, the user separately transmits a measurement report for F2 and F1 to the serving base station. The specific process is as shown in FIG.

  In step 901, after the end of Ttrig2, the user transmits MR related to F2, that is, MR (F2) to the serving base station.

  In steps 902 to 903, the serving base station performs handover determination by MR, selects cell2 (F2) as a target base station, and transmits a handover request to cell2.

  In step 904, after the end of Ttrig1, the user transmits MR related to F1, that is, MR (F1) to the serving base station.

  When the time interval between MR (F1) and MR (F2) reaching the serving base station is too long, the serving base station has already transmitted a handover execution command including cell2 (F2) to the user. Ignore F1). However, if cell1 is dominant based on various causes, such as the RSRP strength, the current load of the cell, the telephone bill, the data rate that can be provided by the system, etc., then the user can use cell1 (F1 ) May be further inclined to select as a target base station. However, the user could not be handed over to the most desirable target base station, cell1 (F1). This affects user satisfaction.

  In LTE and LTE-A, the system bandwidth increases from a 3G maximum bandwidth of 10M to a maximum of 20M and 100M. If the 20M bandwidth is synthesized by multiple discrete 5M bandwidths, or if the 100M bandwidth is synthesized by multiple discrete 20M bandwidths, some users At one time, data can be transmitted / received using only one 5M bandwidth or one 20M bandwidth, and data cannot be transmitted / received using the entire 20M bandwidth or the entire 100M bandwidth. Thus, adjacent cells of different frequencies (inter-F: Inter Frequency) usually exist. At the same time, since the future mobile communication system is a multiple access network in which various radio access technologies coexist, adjacent cells that employ a heterogeneous radio access technology (inter-RAT) are also usually present. Inter-F and inter-RAT handovers are very important to balance load between inter-F and inter-RAT systems and to ensure that users are connected to the best cell This makes the measurement to ensure handover quality even more important. Correspondingly, it seems to be particularly important how to properly deal with the problem of performing measurement with a ring number on a plurality of measurement objects in different frequency measurement.

  In view of the above, the present invention provides a method and apparatus for handover measurement in mobile communication, and a specific implementation is as follows.

  A handover measurement method in mobile communication, wherein a first target set including one or a plurality of measurement targets is determined, and a plurality of unit measurement time zones (Tunits) are assigned to each measurement target in the first target set by a rotation number. , One or a plurality of measurement objects are removed from the first object set to obtain a second object set, a unit measurement time period of the removed measurement object is reassigned, and a unit measurement time period obtained by reassignment And measuring the signal strength of each measurement target in the second target set according to the correspondence between the measurement target and the measurement target in the second target set, and transmitting the measurement report according to the monitoring status of the measurement report trigger event.

  Removing one or more measurement objects from the first object set sets an object removal trigger event, and at least one unit measurement time period of the measurement object in the first object set, the object removal trigger event Is stopped, and the measurement of the signal strength of the measurement object is stopped in a plurality of subsequent unit measurement time periods of the measurement object.

  The target removal trigger event is Mm + Ofm + Ocm + Hys <Mn + Ofn + Ocn−Off, where M is a measurement result of the measurement target, Of is a frequency offset amount of the measurement target, and Oc is a cell offset amount of the measurement target. Hys is a hysteresis coefficient, Off is an event offset amount, a subscript n represents a measurement target having the best signal strength in the first target set, and a subscript m is one measurement target in the first target set. And that the target removal trigger event is monitored in at least one unit measurement time zone of the measurement target in the first target set, the signal strength of the measurement target obtained in the unit measurement time zone, The signal strength of all the measurement targets in the first target set is compared with the best signal strength, and the measurement pair The strength of the signal comprises than the best signal strength, if one of the offset amount small, determines a target removal trigger event is monitored, that.

  The target removal trigger event is Mm + Ofm + Ocm + Hys <Ms + Ofs + Ocs−Off, where M is a measurement result of the measurement target, Of is a frequency offset amount of the measurement target, and Oc is a cell offset amount of the measurement target. Hys is a hysteresis coefficient, Off is an event offset amount, a subscript s represents a serving base station, a subscript m represents one measurement target in the first target set, and a measurement target in the first target set The fact that the target removal trigger event is monitored in at least one unit measurement time zone is that the signal strength of the measurement target obtained in the unit measurement time zone is compared with the signal strength of the serving base station, If the signal strength of the measurement target is one offset smaller than the signal strength of the serving base station, Determining a trigger event has been monitored, comprising.

  The target removal trigger event is Mm + Hys <Threshold, where M is a measurement result of the measurement target, Hys is a hysteresis coefficient, Threshold is a threshold value, and the subscript m is one in the first target set. Representing a measurement object, the fact that the object removal trigger event is monitored in at least one unit measurement time zone of the measurement object in the first object set is that the signal intensity of the measurement object obtained in the unit measurement time zone And a preset threshold value, and if the signal strength of the measurement target is smaller than the threshold value, it is determined that the target removal trigger event is monitored.

  The method sets an object removal observation time, starts the object removal observation time for a removal waiting measurement object after the object removal trigger event is monitored, and performs the removal waiting measurement within the object removal observation time. Monitoring over all unit measurement time zones assigned to the target, and when the target removal trigger event is monitored over all the unit measurement time zones, after the target removal observation time is over, It further includes stopping the measurement and changing the measurement target waiting to be removed to the measurement target that has been removed.

  Reassigning the unit measurement time zone of the removed measurement target means that the user terminal transmits uplink signaling to which the unit measurement time zone is attached to the serving base station, and the user terminal transmits the unit measurement time zone to the serving base station. Informing that the mobile station is stopped at the service frequency in the measurement time zone, the serving base station includes transmitting and receiving data of the user terminal in the unit measurement time zone according to the uplink signaling instruction.

  Reassigning the unit measurement time zone of the removed measurement object includes setting the user terminal to sleep in the unit measurement time zone.

  Reassigning the unit measurement time period of the removed measurement object includes assigning all subsequent unit measurement time periods to each measurement object in the second object set by a rotation number.

  Reallocating the unit measurement time zone of the removed measurement object searches for the measurement object having the maximum signal strength from the second object set, and then sets a plurality of subsequent unit measurement time zones of the removed measurement object, Assigning to the measurement object that maximizes the signal strength.

  The transmission of the measurement report according to the monitoring status of the measurement report trigger event is set by the serving base station for the first measurement target after the measurement report trigger event is monitored for the first measurement target. A first measurement report observation time Ttrig is started, monitored over all unit measurement time zones assigned to the first measurement object in the Ttrig, and the measurement report trigger event is monitored over all unit measurement time zones. In this case, after completion of the Ttrig, a measurement report is transmitted regarding the first measurement object.

  Sending the measurement report according to the monitoring status of the measurement report trigger event sets the second measurement report observation time Ttrig ′ as Ttrig ′ = Ttrig + (Nskip / 2) * Tunit, where Ttrig is the serving The first measurement report observation time set by the base station, Nskip is the number of measurement objects removed, and after the measurement report trigger event is monitored for the first measurement object, the first measurement report observation time is The Ttrig 'is started, the unit is monitored over all unit measurement time zones assigned to the first measurement object in the Ttrig', and the measurement report trigger event is monitored over all the unit measurement time zones. , Transmitting a measurement report regarding the first measurement object after the end of Ttrig ′.

  Sending the measurement report according to the monitoring status of the measurement report trigger event sets the third measurement report observation time Ttrig ″ as Ttrig ″ = T1−mod (T1, mod (T1, Nkeep * Tunit). Here, T1 is the first measurement report observation time Ttrig or the second measurement report observation time Ttrig ', Nkeep is the number of measurement objects in the second object set, and the measurement report trigger event for the first measurement object Is started for the first measurement object, and is monitored over all unit measurement time periods assigned to the first measurement object in the Ttrig '' When the measurement report trigger event is monitored over a unit measurement time period, the first report is executed after the end of the Ttrig ″. Sending a measurement report with respect to a constant target involves.

  The method further includes recovering the measurement of the signal strength of the removed measurement object if it is determined that a preset recovery condition has been met.

  Determining that the preset recovery condition has been satisfied is to start measuring the removal time after removing the measurement object from the first object set, and to determine one or more current times after the removal time is over. If it is not within any measurement report observation time, and if it is not within any measurement report observation time, it is determined that a preset recovery condition has been satisfied, or after all measurement report observation times are over, If it is determined that a preset recovery condition has been satisfied, or the signal strength of the measurement target in the second target set has deteriorated, the first signal strength having the best signal strength among the one or more removed measurement targets is determined. Selecting two measurement objects and determining that the recovery condition for the second measurement object is satisfied.

  Determining a first set of objects including the one or more measurement objects receives a measurement configuration provided from a serving base station, and the one or more measurement objects specified in the measurement configuration Determining a first target set.

  Determining a first target set including the one or more measurement targets is performed by a user terminal searching for a different carrier frequency or access method, and using the searched carrier frequency or access method as a measurement target. Including adding to a set.

  Determining a first target set including the one or more measurement targets may be performed when a user terminal receives a measurement configuration provided from a serving base station, searches for a different carrier frequency or access scheme, Determining the first target set based on the designated measurement target and the measurement target searched by the user terminal.

  The carrier frequency used by the measurement target and the serving base station in the first target set is different, or the access method used by the measurement target and the serving base station in the first target set is different.

  A parameter storage unit that is a user terminal and stores a first target set including one or a plurality of measurement targets, and stores a correspondence relationship between the measurement target and a single measurement time zone (Tunit), and the parameter storage Measure the signal strength of each measurement target based on the correspondence between the measurement target stored in the unit and the unit measurement time zone, send the measurement result to the target control unit, and send the measurement report based on the monitoring status of the measurement report trigger event The measurement execution unit to be set, the correspondence between the measurement target and the unit measurement time zone are set, and one or more measurement targets are removed from the first target set according to the measurement result obtained by the measurement execution unit. Obtain the second target set, reassign the unit measurement time zone of the removed measurement target, and update the correspondence between the measurement target and the unit measurement time zone according to the reassignment result Including a target control unit.

  The target control unit includes a removal definition module for setting a target removal trigger event, and the measurement target after the target removal trigger event is monitored in at least one unit measurement time zone of the measurement target in the first target set. And an object removal module that stops measuring the signal strength of the measurement object in a plurality of subsequent unit measurement time periods.

  The target removal module sets a target removal observation time, and after the target removal trigger event is monitored, starts the target removal observation time for a measurement target waiting for removal, and the removal within the target removal observation time. Monitoring over all unit measurement time zones assigned to the waiting measurement object, and if the target removal trigger event is monitored over all the unit measurement time zones, the removal waiting measurement is performed after the target removal observation time is over. The measurement for the object is stopped, and the measurement object waiting for removal is changed to a measurement object that has been removed.

  The target control unit further includes a unit assignment module that assigns all subsequent unit measurement time zones to each measurement target in the second target set by a rotation number.

  The target control unit searches for a measurement target having the maximum signal strength from the second target set, and assigns a plurality of subsequent unit measurement time zones of the removed measurement target to the measurement target having the maximum signal strength. It further includes a unit assignment module.

  The target control unit further includes a target recovery module that recovers the measurement of the signal strength of the removed measurement target when it is determined that a preset recovery condition is satisfied.

  The parameter storage unit stores measurement settings provided from a serving base station, and the measurement settings are for specifying a first target set including one or more measurement objects.

  The measurement execution unit further searches for a different carrier frequency or access method, and adds the searched carrier frequency or access method as a measurement target to the first target set stored in the parameter storage unit.

  As can be seen from the above solution, the handover measurement method and apparatus according to the present invention eliminates the object removal in the case of different frequencies or different systems if it is necessary to measure a plurality of measurement objects. By setting the trigger event, the measurement target with relatively poor signal strength is temporarily removed, and the unit measurement time zone of the removed target is assigned to the measurement target with relatively good signal strength. Increase monitoring frequency and measurement frequency for good measurement objects.

  Furthermore, in the embodiment of the present invention, Ttrig is adaptively updated, that is, the length of Ttrig can be adaptively changed according to the total number of measurement objects and the number of measurement objects ignored. Further, when the measurement object that triggered the Ttrig is not remeasured within the remaining time of the Ttrig, the measurement report delay is reduced by moving the measurement report forward. In this way, the accuracy and timeliness of the measurement results can be extremely greatly ensured, and the reliability of handover and the call quality of cell edge users can be improved.

It is a flowchart of the hand-over in the conventional method. It is a figure which shows the structure of the multilayer cover network where various radio | wireless access systems coexist. It is a figure which shows that a measurement report is transmitted and a hand-over is performed by the change of the channel quality of a target cell (F2) and a serving cell (F0). It is a figure which shows performing a measurement with a ring number with respect to several measuring object in the conventional method. It is a figure which shows the comparison of the change of the channel quality of the measuring object F2 and the service frequency F0 under the influence of a shadow. It is a figure which shows the comparison of the change of the channel quality of the measuring object F2 and the service frequency F0 under the influence of high-speed fading. It is a figure which shows that a several measuring object triggers Ttrig time measurement substantially simultaneously. It is a figure which shows that several measurement object transmits a measurement report to a serving base station substantially simultaneously in the conventional method. It is a flowchart of transmission of a plurality of measurement reports. 3 is a flowchart of an inter-frequency / system-to-system handover measurement method according to the present invention. 6 is a flowchart of a method for removing a measurement object having a relatively low signal strength by a user according to an embodiment of the present invention. 4 is a flowchart of a method for a user to update Ttrig in one embodiment of the present invention. FIG. 6 is a diagram showing Ttrig update in one embodiment of the present invention. In one Example of this invention, after removing the comparatively bad measurement object, it is the sequence diagram of the measurement by which the conventional Ttrig timing was triggered. 1 is a configuration diagram of an apparatus for performing a handover measurement according to the present invention. FIG. 1 is a block diagram of an apparatus for setting a target removal trigger event in one embodiment of the present invention. FIG. In one Example of this invention, it is a block diagram of the apparatus for removing the measurement object with comparatively bad signal strength, and recovering this measurement object. FIG. 3 is a block diagram of an apparatus for updating Ttrig in one embodiment of the present invention. It is a figure which shows the comparison of the handover stability at the time of employ | adopting Ttrig after an update in one specific example of this invention, and the handover stability of the conventional method. In one specific example of this invention, after removing a measuring object, it is a figure which shows the comparison with the measurement report delay at the time of employ | adopting conventional Ttrig, and the measurement report delay of a conventional method. FIG. 6 is a diagram showing a comparison between a transmission time interval of measurement reports of two different measurement objects and a transmission time interval in a conventional method in one specific example of the present invention.

  In order to further clarify the object, solution, and merit of the present invention, the present invention will be described in more detail below with reference to the drawings.

  The embodiments of the present invention provide a method for performing handover measurement between frequencies / systems in a user terminal. In the method, the user terminal includes determining a first target set including one or a plurality of measurement objects, and assigning a plurality of unit measurement time zones Tunit to each measurement object in the first target set by a rotation number.

  Here, the specific method for the user terminal to determine the first target set is to receive the measurement setting provided from the serving base station and obtain the designated first target set from the measurement setting. Alternatively, the user terminal may search for different carrier frequencies or access schemes, and finally form the first target set using the searched carrier frequencies or access schemes as measurement targets.

  Next, the user terminal removes one or a plurality of measurement targets to obtain a second target set according to a measurement situation with respect to the signal strength of the measurement target in the first target set, and sets a unit measurement time zone of the removed measurement target. Reassign.

  That is, since the removed measurement object no longer uses the unit measurement time period, these unit measurement time periods that have become idle can be reassigned to one or more measurement objects in the second object set. For example, when these unit measurement time zones that have become idle are uniformly assigned to all measurement targets in the second target set, it is necessary to readjust the entire previously set correspondence. When these unit measurement time zones that have become idle are assigned only to the measurement target having the maximum signal strength in the second target set, the unit measurement time zones previously assigned to other measurement targets need not be readjusted. .

  Finally, the signal strength of each measurement target in the second target set is measured, and a measurement report is transmitted according to the monitoring status of the measurement report trigger event. Here, the measurement object to be removed is usually a measurement object having a relatively poor signal quality.

  Here, the measurement setting is for designating a first object set including one or more measurement objects. In the measurement setting, a measurement time is set. That is, one or a plurality of measurement times are pre-divided by the serving base station, and the user assigns these measurement times to each measurement target in the first target set in a rotation number for each unit measurement time zone (Tunit), that is, The correspondence between the unit and the measurement target is set by the user.

  FIG. 10 is a flowchart of a handover measurement method according to the present invention. The method includes the following steps.

  In step 1001, the measurement setting provided from the serving base station is received, and the measurement target specified by the measurement setting is obtained. In the embodiment of the present invention, the set of measurement objects is called a first object set.

  In step 1002, the user obtains a second target set by removing one or more measurement targets having relatively poor signal quality from the first target set according to a certain rule in the course of measurement.

  In step 1002, the process of removing one or more measurement objects with relatively poor signal quality is triggered by an object removal trigger event (EventC). That is, when it is detected that the signal intensity of the measurement target satisfies EventC within a unit measurement time zone assigned to a measurement target, the measurement target may be directly removed. Generally, a measurement object having a relatively bad signal strength is removed.

  When applied specifically, the object removal trigger event (EventC) may have various implementation methods, and will be described below with three examples. As to be described here, since the measurement report trigger events A1 to A5 and B1 to B2 are already defined in TS 36.331, three specific implementations of the target removal trigger event (EventC) can be realized. Name it C3. In the following definition, the measurement object F3 has a relatively low signal strength (hereinafter also referred to as a relatively bad measurement object), and the measurement object F2 has the best signal strength (hereinafter also referred to as the best measurement object). Suppose that

  Event C1 is that, as shown in inequality (2), the signal strength of the relatively poor measurement target F3 is one offset smaller than the best measurement target F2.

M3 + Of3 + Oc3 + Hys <M2 + Of2 + Oc2-Off (2)
The reason for setting EventC1 is that the signal strength of F3 is relatively poor compared to F2. Therefore, since the signal strength of F3 is one offset larger than the service frequency F0, even if it can be selected as the target base station, the signal strength of F2 is one higher than that of F3 after the user hands over to F3. Since the offset amount is large, the user will be handed over immediately from F3 to F2. Such frequent handover affects the user's call quality. Therefore, the measurement efficiency can be improved by removing F3 from the first target set. In addition, by setting TtrigC and offset amount Off, it is possible to guarantee that the possibility that the signal strength of F3 is larger than the signal strength of F2 within the removal time (Tskip) is very low, and the accuracy of measurement is also guaranteed. .

  More generally, inequality (2) can be expressed as:

Mm + Ofm + Ocm + Hys <Mn + Ofn + Ocn-Off
Here, the subscript m represents a certain measurement object in the first object set, and n represents the measurement object having the best signal strength in the first object set.

  (2) Event C2, as shown in inequality (3), is that the signal strength of a relatively bad measurement target is one offset amount smaller than the service frequency.

M3 + Of3 + Oc3 + Hys <Ms + Ofs + Ocs-Off (3)
(3) Event C3 is that the signal strength of a relatively bad measurement target is smaller than the absolute threshold, as shown in inequality (4).

M3 + Hys <Threshold (4)
By setting TtrigC and offset amount Off for EventC2 and EventC3, it is very unlikely that the signal strength of F3 will increase to satisfy the target base station within the removal time (Tskip). It is reasonable to ignore without measuring for F3 in Tskip.

  In addition, an observation period may be set for the target removal trigger event. This observation period is an object removal observation time (TtrigC), and its role is similar to that of Ttrig. However, Ttrig is an observation period set for the measurement report trigger event. When it is detected that the signal strength of the measurement target satisfies EventC within the unit measurement time zone assigned to a certain measurement target, the unit measurement time zone is used as the starting point of the target removal observation time (TtrigC). Are continuously detected in the unit measurement time zone belonging to the measurement object. When the signal strength of the measurement target satisfies EventC over all the unit measurement time zones assigned to the measurement target in TtrigC, the measurement target is removed after the end of TtrigC. Specifically, TtrigC may be set for three events C1 to C3. That is, only when any of these three events is satisfied over the TtrigC period, the target removal process can be performed and the relatively bad measurement target can be ignored.

  Further, the number of relatively bad measurement objects can be determined by the minimum number of measurement objects (Nmin). Here, Nmin is for designating the number of measurement objects that need to be left at least. For example, at least two measurement objects are left.

  In step 1003, the unit measurement time zone of the removed measurement target is reassigned.

  Consider how to use the unit measurement time zone of the removed measurement target after the target removal trigger event is satisfied and the TtrigC time has elapsed, after the relatively bad measurement target is removed. Also good. In a specific example of the present invention, the following three types of schemes are provided.

  1. By assigning the removed measurement target unit to the service frequency F0 and using it for uplink / downlink communication with the base station, the communication quality of the user is improved. Specifically, the user notifies the serving base station that the user has stopped at the service frequency by these tunits by transmitting uplink signaling to the serving base station, and continuously transmits and receives data related to the user. Request that. This scheme can improve user throughput.

  2. The user sleeps in the unit measurement time zone (including a plurality of measurement gaps) of the removed measurement target. This method can save power, does not require any extra processing, and saves power consumption of the mobile terminal.

  3. The user resets the correspondence between all unit measurement time zones and the measurement objects in the second object set. This method does not require an extra signaling load.

  There are the following two specific implementations for setting the correspondence relationship of method 3.

  (1) Reassign the Units according to the number of measurement objects included in the second object set, and perform measurement on the measurement objects in the second object set using the reassigned Tunit.

  The measurement targets specified by the serving base station are F1 to F4, and the unit measurement time zone numbers are Tunit1, Tunit2, Tunit3, Tunit4, Tunit5, Tunit6,... Assume that the unit measurement time zones assigned, ie, previously assigned to F1, are Tunit1, Tunit5, Tunit9,. After F2 is removed, all Units are assigned again in the second target set as a rotation number, so the unit measurement time zones assigned to F1 are Tunit1, Tunit4, Tunit7,. Here, each Tunit is a set of a plurality of measurement gaps.

  (2) The unit measurement time zone of the removed measurement object is assigned to the measurement object having a relatively good signal strength in the second object set, thereby enhancing the measurement for the measurement object having a relatively good signal strength.

  For (2) above, if no Ttrig has been started, the reassignment can increase the monitoring frequency of the measurement target having a relatively good signal strength and start the Ttrig in a timely manner. , Send measurement reports in a timely manner. If there is a starting Ttrig, assigning a unit measurement time zone to a measurement target having a relatively good signal strength increases the number of measurements for a measurement target having a relatively good signal strength in the Ttrig period, thereby improving the accuracy of the measurement result. Sexuality can be guaranteed.

  In step 1004, measurement is performed on all measurement objects in the second object set, measurement results are obtained, and a measurement report is transmitted according to the monitoring status of the measurement report trigger event.

  In step 1005, the measurement of the signal intensity may be recovered for the removed measurement object according to a predetermined recovery condition. This further matches the measurement to the actual signal conditions of the network, eg avoiding the fact that the signal strength of a certain removed measurement object has been improved, but it is ignored and causes a Ttrig delay.

  In concrete implementation, the following three types of methods may be adopted to set the recovery condition for the removed measurement object.

  1. After all Ttrigs are completed, the measurement for the removed measurement object is restored.

  2. When one of the remaining measurement targets with relatively good signal strength suddenly deteriorates, one measurement target with relatively good signal strength is determined from the plurality of removed measurement targets. Then, the measurement for the measurement object is recovered.

  3. When the removal time (Tskip) is set and Ttrig is not started for any measurement object after the completion of Tskip, the measurement for the removed measurement object is restored. The value of Tskip may be set independently for EventC1, EventC2, and EventC3.

  As can be seen from FIG. 10, in step 1001 of FIG. 10, the first target set is obtained by receiving the measurement setting provided from the serving base station. When specifically realizing, the user terminal itself may search for the measurement target to form the first target set. For example, at power-on, the user terminal selects and accesses one appropriate cell by searching in all accessible frequencies, stores the searched frequency or access method, and stores the first target set. It may be added to. Further, for example, after accessing an appropriate cell, the user terminal may read the broadcast information of the cell and obtain some information of the measurement target that can be added to the first target set from the broadcast information. . The obtained information includes information on a measurement object such as a different frequency or a different system. Further, for example, when the user terminal enters the idle state, the user terminal may search for a different measurement target. This search may be periodic or triggered by an event. Further, for example, the user may search for a new measurement target such as a different frequency or a different system using the measurement gap after transitioning to the connected state. This search may be periodic or triggered by an event. It should be explained here that once a new measurement target is searched, the user terminal can add it to the first target set.

  In either of the two types of methods, that is, the setting by the base station and the search by the user, the first target set may be constantly updated. In the case of setting by the base station, the base station can change the measurement target at any time, and the user terminal updates the first target set by receiving the measurement setting of the base station in the connected state. Moreover, you may use combining these two types of systems. For example, the first target set may be determined based on the measurement target specified by the measurement setting and the measurement target searched by the user terminal.

  FIG. 11 is a flowchart of a method for removing a measurement object having a relatively low signal strength by a user in one embodiment of the present invention.

  In step 1101, after receiving the measurement setting of the serving base station, the user terminal starts measurement for the measurement target. When EventC is set by the serving base station, the user may execute according to the setting. Otherwise, the user terminal itself sets a target removal trigger event (EventC) according to the measurement result in a certain period, and sets parameters such as the minimum number of measurement targets (Nmin) that need to be left.

  In step 1102, the set number of measurement objects (Noject) is compared with Nmin. If Noject> Nmin, step 1103 is executed. Otherwise, the process is terminated without removing the target.

  In step 1103, the user monitors whether or not the signal strength of the corresponding measurement target satisfies EventC in each unit measurement time zone. If a measurement target satisfies EventC, step 1104 is executed; 1103 is repeatedly executed.

  In step 1104, the user starts TtrigC timing for the measurement object.

  In Step 1105, during the measurement of TtrigC, measurement is continuously performed on a plurality of measurement targets with a rotation number, and when the measurement result for the measurement target that triggered TtrigC satisfies EventC within the unit assigned to the TtrigC, after completion of TtrigC, 1106 is executed. Otherwise, the process ends.

  In step 1106, the user removes the measurement object, i.e., no measurement is performed on the measurement object within the next Tskip period.

  In addition, after removing one or more measurement objects, the measurement report set by the user is updated by updating the measurement report observation time (Ttrig) set by the base station using the saved Ttrig delay. An observation time (Tx) may be obtained and stored in the user terminal.

  The number of measurement targets set for the user by the serving base station is Noject, the number of measurement targets with relatively poor signal strength removed is Nskip, and the number of measurement targets with relatively good signal strength remaining is Nkeep. Suppose that With respect to the removed Nskip measurement objects, all subsequent Tunits are assigned to Nkeep measurement objects in the second object set by the rotation number. In this case, when the number of objects to be measured is N, the average Ttrig delay is as shown in Expression (5).

Trigdelay = {(N−1) / 2} * Tunit (5)
Furthermore, the Ttrig delay saved by removing a relatively bad measurement object is as shown in equation (6).

δTtrigdelay = (Nskip / 2) * Tunit (6)
Therefore, as shown in Formula (7), Ttrig can be updated to Ttrig ′.

Ttrig '= Ttrig + (Nskip / 2) * Tunit (7)
Further, when the number of Tunits included in Ttrig is not an integral multiple of the number of objects to be measured, measurement in a short period immediately before the end of Ttrig is not useful for the object to be measured that triggered Ttrig. Therefore, the short period may be skipped. Thereby, the transmission of the measurement report is carried forward. Specifically, when Ttrig 'is a multiple of Nkeep * Tunit, the measurement result in one unit immediately before the end of Ttrig' is for the measurement object that triggered Ttrig, and is useful for the measurement report. The transmission needs to wait until after the end of Ttrig '. When Ttrig ′ is not a multiple of Nkeep * Tunit, the measurement results at one or more Tunits immediately before the end of Ttrig ′ are not for the measurement object that triggered Ttrig, and are not useful for measurement reporting. In this case, as shown in equation (8), Ttrig can be further updated to Ttrig ″, thereby raising the transmission of the measurement report.

Ttrig '' = Ttrig'-mod (Ttrig ', Nkeep * Tunit) (8)
Here, Tunit is the length of time required for measurement of one measurement object, and generally has a value of 480 ms.

  Table 3 shows updated values of Ttrig when five measurement objects are set in the serving base station and Nkeep is 2, 3, and 4, respectively. Here, the parameter value representing the time is obtained by multiplying the value in Table 3 by 480 ms.

  As can be seen from Table 3, according to Equation (7), the saved Ttrig delay is used to increase the length of Ttrig to obtain Ttrig ′, and the number of measurement times of the measurement target is obtained by performing observation in the Ttrig ′ period. Increase the accuracy of the measurement results. Next, according to equation (8), the measurement reporting delay can be reduced to some extent by further optimizing Ttrig '. If it is desired to further reduce the measurement reporting delay, the saved Ttrig delay may not be used to increase the length of Ttrig. Thus, when the number of objects to be measured is reduced, the discovery of Event A3 can be carried forward and measurement report observation can be performed using the conventional Ttrig.

  Of course, the conventional Ttrig can also be updated as shown in Expression (9) to obtain Ttrig ″. The update is similar to equation (8). Table 4 shows the effect of updating the Ttrig using only the equation (9) when the conventional Ttrig is adopted.

  Ttrig "" = Ttrig'-mod (Ttrig, Nkeep * Tunit) (9)

  In Tables 3 and 4, the number of measurements can reflect the accuracy of the measurement results, and the greater the number of measurements, the more accurate the measurement results. The MR delay represents the time to delay the handover. The larger the measurement report delay, the slower the handover and the greater the possibility of a user call drop. In Table 3, MR delay is the sum of Ttrig delay and Ttrig ″, and in Table 4, MR delay is the sum of Ttrig delay and Ttrig ″ ″.

  Comparing Table 3 and Table 4, when the measurement object is removed, increasing the Ttrig with the saved time gives a more accurate measurement result, but uses the conventional Ttrig. Perhaps a shorter measurement reporting delay is obtained. As can be seen, the delay and accuracy of the measurement report cannot be obtained simultaneously. The method of Table 3 aims to further improve the accuracy of measurement reporting, but the measurement reporting delay is slightly reduced. The method of Table 4 further reduces the measurement reporting delay, but does not improve the accuracy of the measurement reporting.

  Furthermore, even if the number of objects to be measured is not reduced, an update similar to that shown in Expression (9) can be performed on the conventional Ttrig. At this time, it is only necessary to replace Nkeep with Noject, that is, Ttrig '' '' = Ttrig-mod (Ttrig, Noject * Tunit).

  As can be seen, the measurement report observation time (Tx) set by the user may directly take Ttrig, and is a value obtained by updating Ttrig, for example, Ttrig ′, Ttrig ″, Ttrig ′ ″, Ttrig ′. '' 'Etc. may be taken.

  FIG. 12 is a flowchart of a method for a user to update Ttrig to Ttrig 'or Ttrig "in one embodiment of the present invention.

  In step 1201, if the user detects that the signal strength of a certain measurement target satisfies a condition for becoming a target base station (for example, Event A3) in the process of measurement, step 1202 is executed. Exit.

  In step 1202, it is determined whether the number of objects to be measured (Noject) set by the base station is larger than the current number of objects to be measured (Nkeep). If so, step 1204 is executed; otherwise, step 1203 is executed. Execute.

  In step 1203, Ttrig is left as it is, and this process is terminated.

  In step 1204, Ttrig delay saved by removal of one or more measurement objects is calculated according to equation (6).

  In step 1205, Ttrig is updated to Ttrig 'according to equation (7).

  In step 1206, it is determined whether Ttrig 'is a multiple of Nkeep * Tunit. If Ttrig 'is a multiple of Nkeep * Tunit, step 1207 is executed; otherwise, step 1208 is executed.

  In step 1207, Ttrig 'is left as it is, and this process ends.

  In step 1208, Ttrig 'is updated to Ttrig "according to equation (8), and the process ends.

  It should be noted that the process may be terminated by executing until step 1205, and steps 1206 to 1208 are selectable execution steps.

  FIG. 13 is a diagram illustrating the update of the Ttrig value in one embodiment of the present invention, where Ttrig 'and Ttrig' 'are shown. In FIG. 13, Ttrig ′ is 2.4 s, which includes five tunits, and there are currently three measurement objects F1, F2, and F3. Then, since the 4th and 5th Units are not useful for the measurement object that triggered Ttrig, the measurement is performed by updating Ttrig to Ttrig ″ (ie, 3 Tunits) using Equation (8). You can carry forward the report.

  FIG. 14 is a diagram showing a measurement in which a conventional Ttrig timing is triggered after removing a relatively bad measurement object in one embodiment of the present invention. Assuming that the signal strength of F3 is the worst, after removing F3, only F1 and F2 remain as measurement objects. Thus, if F2 already satisfies the measurement report trigger event, at most, it will be monitored simply by waiting until the measurement of F1 is completed. This reduces the trigger delay of Ttrig and ensures the timeliness of measurement reports. In the conventional Ttrig period, the number of times F2 is monitored is increased from once to twice, and the frequency of monitoring the frequency is increased to ensure the accuracy of the measurement report. As can be seen, the arrival time interval between the two measurement results is also reduced due to the decrease in the measurement object. This helps the serving base station to select the most appropriate target base station.

  Corresponding to the method according to the present invention, the present invention also provides an apparatus for performing a handover measurement as shown in FIG. FIG. 15 is a block diagram of an apparatus for performing handover measurement according to the present invention. The apparatus includes the following units:

  The parameter storage unit 1501 stores a first target set including one or a plurality of measurement objects, and stores a correspondence relationship between the measurement objects and the single measurement time zone Tunit.

  Specifically, the parameter storage unit 1501 may store the measurement settings provided from the serving base station. The measurement setting is for designating a first object set including one or more measurement objects.

  The measurement execution unit 1502 measures the signal strength of each measurement object according to the correspondence relationship between the measurement object stored in the parameter storage unit and the unit measurement time zone, transmits the measurement result to the object control unit 1503, and measures the measurement report. Send a measurement report according to the monitoring status of the trigger event.

  Furthermore, the measurement execution unit 1502 searches for a different carrier frequency or access method, and adds the searched carrier frequency or access method as a measurement target to the first target set stored in the parameter storage unit 1501. At this time, the first target set stored in the parameter storage unit 1501 has been searched by the user terminal itself.

  Alternatively, the first target set stored in the parameter storage unit 1501 may include the measurement target set by the base station, or may include the measurement target searched by the terminal.

  The target control unit 1503 sets the correspondence between the measurement target and the unit measurement time zone, and removes one or more measurement targets from the first target set according to the measurement result obtained by the measurement execution unit. The second target set is obtained, the unit measurement time zone of the removed measurement target is reassigned, and the correspondence relationship between the measurement target and the unit measurement time zone is updated according to the reassignment result.

  Specifically, in the target control unit 1503, a removal definition module 1513 and a target removal module 1523 may be provided. Here, the removal definition module 1513 sets a target removal trigger event and stores it in the parameter storage unit 1501. The object removal module 1523 may be configured to detect the object removal trigger event in at least one unit measurement time period of the measurement object in the first object set, and then perform a plurality of unit measurement time periods subsequent to the measurement object in the plurality of unit measurement time periods. Stop measuring the signal strength of the measurement target.

  Specifically, the target removal module 1523 sets the target removal observation time (TtrigC), and after the target removal trigger event is monitored, the target removal module 1523 starts the TtrigC for a certain measurement target waiting to be removed, and the TtrigC within the TtrigC Monitor over all unit measurement time periods assigned to the measurement target waiting for removal. Further, when the target removal trigger event is monitored over all the unit measurement time periods, the target removal module 1523 stops the measurement for the measurement target waiting for removal after the end of TtrigC, and the measurement target waiting for removal has been removed. Change to measurement target.

  Further, in the target control unit 1503, a unit assignment module 1533 may be provided. The Tunit assignment module 1533 assigns all subsequent unit measurement target time zones of the removed measurement target to each measurement target in the second target set by a rotation number, or selects a measurement target having the maximum signal strength from the second target set. Search and assign a plurality of subsequent unit measurement time zones of the removed measurement target to the measurement target having the maximum signal intensity, and the parameter storage unit indicates the correspondence between the updated measurement target and the unit measurement time zone 1501 is stored.

  Furthermore, a target recovery module 1543 may be provided in the target control unit 1503. If the target recovery module 1543 determines that a preset recovery condition has been met, the target recovery module 1543 recovers the measurement of the signal strength of the removed measurement target.

  As can be seen from this, the correspondence relationship between the measurement object and the unit measurement time zone is constantly updated. Once the object removal trigger event is satisfied, there is removal of the measurement object. Correspondingly, the correspondence between the measurement object and the unit measurement time zone is adjusted, for example, the unit measurement time zone of the removed measurement object is reassigned to another measurement object. Since the updated correspondence relationship is stored in the parameter storage unit 1501, the measurement execution unit 1502 determines the signal strength of a certain measurement target in a corresponding unit measurement time zone according to the updated correspondence relationship when executing the measurement. Can be measured.

  Furthermore, in order to set the object removal trigger event, the embodiment of the present invention provides a user terminal. FIG. 16 is a block diagram of a user terminal for setting a target removal trigger event in one embodiment of the present invention. The user terminal includes a parameter storage unit 1601, a measurement execution unit 1602, an event definition unit 1603, and an event evaluation unit 1604.

  The parameter storage unit 1601 includes measurement parameters set by the base station, target removal trigger event (EventC) and EventC parameters provided from the event definition unit 1603, and measurement target and unit measurement time set by the event evaluation unit 1604. The correspondence with the belt is stored.

  Here, the correspondence between the measurement object and the unit measurement time zone is updated according to the monitoring status of EventC.

  What is stored in the parameter storage unit 1601 at the beginning of the measurement is the correspondence between the unit measurement time zone and all the measurement objects in the first object set. Here, the measurement target in the first target set is set by the base station.

  After one or more objects are removed, the correspondence relationship between the measurement object and the unit measurement time zone is updated to the correspondence relationship between the unit measurement time zone and all the measurement objects in the second object set. Specifically, one or more measurement objects are removed from the first object set to obtain a second object set.

  The measurement execution unit 1602 measures the corresponding measurement object in each unit measurement time zone according to the correspondence relationship between the measurement object stored in the parameter storage unit 1601 and the unit measurement time zone, and sends the measurement result to the event definition unit. 1603 and the event evaluation unit 1604.

  The event definition unit 1603 defines a target removal trigger event, sets an EventC parameter according to a measurement result in a certain period, and transmits the defined target removal trigger event and the set EventC parameter to the parameter storage unit 1601. To do. The functions of the event definition unit 1603 and the removal definition module 1513 in FIG. 15 are similar.

  When specifically realizing, the event definition unit 1603 may define EventC1, EventC2, or EventC3 as EventC. When EventC1 is set as a target removal trigger event, it is necessary to determine the best measurement target n within the period. The EventC parameter corresponding to EventC1 includes the measurement result Mn of the best measurement target n, the frequency offset amount Ofn of the best measurement target n, the cell offset amount Ocn of the best measurement target n, the hysteresis coefficient Hys, the event offset amount Off, etc. including.

  Also, the base station may set EventC and EventC parameters and provide them to the user terminal, and the user terminal may perform target removal according to the setting by the base station. In this case, the event definition unit 1603 may not be provided in the user terminal.

  The event evaluation unit 1604 initializes the correspondence relationship between the measurement target and the unit measurement time zone, evaluates the measurement result of the measurement target based on the target removal trigger event stored in the parameter storage unit 1601, and performs a certain target removal trigger. When the event is satisfied, the correspondence relationship between the measurement target and the unit measurement time zone stored in the parameter storage unit 1601 is updated. The basic functions of the event evaluation unit 1604 and the object removal module 1523 in FIG. 15 are similar.

  Specifically, when the update is performed, the measurement target is deleted from the first target set, the unit measurement time zone of the measurement target is reassigned, and the measurement target and the unit measurement time zone obtained by the reallocation are reassigned. Is stored in the parameter storage unit 1601.

  Furthermore, FIG. 17 is a block diagram of an apparatus for removing a measurement object having a relatively low signal strength and recovering the measurement object in one embodiment of the present invention. The apparatus includes a parameter storage unit 1701, a measurement execution unit 1702, an event evaluation unit 1704, and a removal target timing unit 1705.

  The parameter storage unit 1701 stores the measurement parameter and target removal trigger event (EventC) set by the base station, and removes one or more measurement targets set by the base station by the notification of the removal target timing unit 1705. Or recover.

  The measurement execution unit 1702 performs measurement using the measurement parameters stored in the parameter storage unit 1701 and transmits the measurement result to the event evaluation unit 1704.

  The event evaluation unit 1704 evaluates the measurement result from the measurement execution unit 1702 based on the setting related to EventC in the parameter storage unit 1701, and notifies the removal target timing unit 1705 when the EventC is satisfied. Further, the event evaluation unit 1704 determines whether or not a certain measurement target satisfies EventC over the TtrigC period, and notifies the removal target timing unit 1705 if it satisfies.

  The removal target timing unit 1705 receives the notification from the event evaluation unit 1704, starts TtrigC timing for a certain measurement target, and notifies the parameter storage unit 1701 to remove the measurement target after the TtrigC timing ends. The correspondence relationship between the measurement object and the unit measurement time zone in the parameter storage unit 1701 is updated. In the correspondence after the update, the unit measurement time zone is not assigned to the removed measurement object.

  Further, the removal target timing unit 1705 starts the Tskip timing for the measurement target after a certain measurement target is removed, and after the completion of the Tskip timing, or when another recovery condition for the measurement target is satisfied. When judged by the evaluation unit 1704, the parameter storage unit 1701 is notified to recover the measurement object, that is, the unit measurement time zone is reassigned to the recovered measurement object.

  In a specific application, the removal target timing unit 1705 can be realized by employing one or more timers.

  Furthermore, FIG. 18 is a block diagram of an apparatus for updating Ttrig in one embodiment of the present invention. The apparatus includes a parameter storage unit 1801, a measurement execution unit 1802, an event evaluation unit 1804, and an observation time update unit 1806. here,

  The parameter storage unit 1801 stores measurement settings provided from the serving base station (for example, the number of objects to be measured Nobject), and stores the measurement report observation time (Tx) set by the user. Initially, the value of Tx is Ttrig.

  The measurement execution unit 1802 acquires the measurement setting stored in the parameter storage unit 1801, measures the signal strength between the measurement target and the service frequency, and transmits the measurement result to the event evaluation unit 1804.

  The event evaluation unit 1804 makes a determination based on the measurement result provided from the measurement execution unit 1802 and the target removal trigger event provided from the parameter storage unit 1801, and when the measurement result of a certain measurement target satisfies the target removal trigger event When it is determined, the observation time update unit 1806 is notified.

  The observation time update unit 1806 receives the notification from the event evaluation unit 1804, calculates Ttrig ′ and Ttrig ″, compares the Noject stored in the parameter storage unit 1801 with the current number of measurement objects, and compares As a result, Ttrig ′ and Ttrig ″ are stored in the parameter storage unit 1801 as updated Tx values.

  Further, the event evaluation unit 1804 acquires the updated Tx value from the parameter storage unit 1801, and determines the time for transmitting the measurement report based on the updated Tx value. The Tx value is updated from Ttrig to Ttrig 'or Ttrig ", thereby further improving the accuracy of the measurement report.

  FIG. 19 is a diagram illustrating a comparison between the handover stability when the Ttrig is updated to Ttrig ′ and Ttrig ″ in one specific example of the present invention and the handover stability of the conventional method. Here, the conventional method means that all the measurement objects set by the serving base station are measured with a rotation number and a fixed measurement report observation time (Ttrig) is used. In a specific example of the present invention, a measurement object having a relatively low signal strength is removed, the saved Ttrig delay is used for extending the Ttrig, and the measurement object corresponding to the Ttrig immediately before the end of the Ttrig is invalid. Remove the unit measurement time zone and advance the measurement report transmission.

  As can be seen from the simulation results, after a measurement report trigger event is satisfied for a certain measurement object, according to a specific embodiment of the present invention, the measurement frequency of the measurement object is increased to increase the accuracy of the measurement result. Improve the degree. Thereby, the serving base station can more appropriately select a reliable target base station based on the measurement report. Therefore, after the user hands over to the target base station selected by the above method, re-handover does not occur within a short period. This improves handover stability, reduces unnecessary handovers, reduces user interruption time, and improves user throughput and user satisfaction.

  FIG. 20 shows a comparison between the measurement report delay of the conventional method and the measurement report delay when the Ttrig is updated to Ttrig ″ ′ after the measurement object is removed in one specific example of the present invention. FIG. In FIG. 20, in a specific example of the present invention, a measurement object having a relatively low signal strength is removed, the saved Ttrig delay is used to reduce the measurement report delay, and an invalid unit measurement time zone immediately before the end of the Ttrig is used. Remove and advance sending of measurement report. As can be seen, compared to conventional methods, the specific example of the present invention further reduces the measurement reporting delay much more and ensures that the user is handed over in a timely manner.

  FIG. 21 is a diagram showing a comparison between transmission time intervals of measurement reports of two different measurement objects in one specific example of the present invention and transmission time intervals in the conventional method. The two different measurement objects refer to two different frequencies. In FIG. 21, in a specific example of the present invention, two Ttrig triggers are used to reduce the measurement interval between two measurement objects having relatively good signal strength by removing measurement objects having relatively poor signal strength. Decrease the time interval and finally reduce the transmission time interval of the two measurement reports.

  When the time interval between two measurement reports reaching the serving base station decreases, the serving base station transmits a handover execution command including cell2 (F2) to the user when receiving the measurement report of cell1 (F1). It may not be. Then, the serving base station makes a handover decision again, selects cell1 (F1) as the target base station, and transmits a handover cancel command to cell2 (F2), thereby cell2 (F2). To notify the user in a timely manner that the user will not be handed over to it. That is, before the handover execution command including cell2 (F2) is transmitted from the serving base station, the handover has already been canceled. At the same time, the serving base station transmits a handover request command to cell1 (F1). After that, processes such as handover preparation and handover execution are performed.

As can be seen, by reducing the time interval between measurement reports, it can be ensured that the user can be handed over to the best target base station, and the user is connected to the best target base station much more. This avoids the problem shown in FIG. 9 and improves the user's service satisfaction.
The above are only preferred embodiments of the present invention and do not limit the protection scope of the present invention. Various modifications, equivalent replacements, improvements and the like made within the spirit and principle of the present invention should all be included in the protection scope of the present invention.

Claims (27)

A method for measuring handover in mobile communication,
Determining a first object set including one or more measurement objects, assigning a plurality of unit measurement time zones (Tunits) to each measurement object in the first object set by a rotation number;
Removing one or more measurement objects from the first object set to obtain a second object set, and reallocating a unit measurement time zone of the removed measurement object;
The signal strength of each measurement target in the second target set is measured based on the correspondence relationship between the unit measurement time zone obtained by reassignment and the measurement target in the second target set, and measured according to the monitoring status of the measurement report trigger event. Send report,
A method comprising: Removing one or more measurement objects from the first set of objects;
Set the target removal trigger event,
After the target removal trigger event is monitored in at least one unit measurement time zone of the measurement target in the first target set, the signal strength of the measurement target is measured in a plurality of subsequent unit measurement time zones of the measurement target. Stop measuring,
The method of claim 1, comprising: The target removal trigger event is Mm + Ofm + Ocm + Hys <Mn + Ofn + Ocn−Off,
Here, M is the measurement result of the measurement target, Of is the frequency offset amount of the measurement target, Oc is the cell offset amount of the measurement target, Hys is the hysteresis coefficient, Off is the event offset amount,
The subscript n represents the measurement object having the best signal strength in the first object set, the subscript m represents one measurement object in the first object set,
The object removal trigger event is monitored in at least one unit measurement time zone of the measurement object in the first object set,
The signal strength of the measurement target obtained in the unit measurement time period is compared with the best signal strength of all the measurement target signal strengths in the first target set, and the signal strength of the measurement target is the best. Determining that an object removal trigger event has been monitored if one offset amount is less than the signal strength;
The method according to claim 2. The target removal trigger event is Mm + Ofm + Ocm + Hys <Ms + Ofs + Ocs−Off,
Here, M is the measurement result of the measurement target, Of is the frequency offset amount of the measurement target, Oc is the cell offset amount of the measurement target, Hys is the hysteresis coefficient, Off is the event offset amount,
The subscript s represents the serving base station, the subscript m represents one measurement target in the first target set,
The object removal trigger event is monitored in at least one unit measurement time zone of the measurement object in the first object set,
When the signal strength of the measurement target obtained in the unit measurement time period is compared with the signal strength of the serving base station, and the signal strength of the measurement target is one offset amount smaller than the signal strength of the serving base station, the target Determining that a removal trigger event has been monitored,
The method according to claim 2. The target removal trigger event is Mm + Hys <Threshold.
Here, M is the measurement result of the measurement object, Hys is the hysteresis coefficient, Threshold is the threshold value, the subscript m represents one measurement object in the first object set,
The object removal trigger event is monitored in at least one unit measurement time zone of the measurement object in the first object set,
The signal strength of the measurement target obtained in the unit measurement time period is compared with a preset threshold value, and when the signal strength of the measurement target is smaller than the threshold value, it is determined that the target removal trigger event is monitored. Including,
The method according to claim 2. After the target removal observation time is set and the target removal trigger event is monitored, the target removal observation time is started for the measurement object waiting for removal and assigned to the measurement object waiting for removal within the target removal observation time. Monitoring over all unit measurement times
When the target removal trigger event is monitored over all the unit measurement time periods, after the target removal observation time ends, the measurement for the measurement target waiting for removal is stopped and the measurement target waiting for removal is removed. Change to
The method according to any one of claims 2 to 5, further comprising: Reassigning the unit measurement time zone of the removed measurement object,
The user terminal transmits uplink signaling to which the unit measurement time zone is attached to the serving base station, and notifies the serving base station that the user terminal is stopped at the service frequency in the unit measurement time zone,
The serving base station transmits / receives data of the user terminal in the unit measurement time period according to the instruction of the uplink signaling.
The method of claim 1, comprising:   The method according to claim 1, wherein reassigning the unit measurement time zone of the removed measurement target includes setting a user terminal to sleep in the unit measurement time zone. Reassigning the unit measurement time zone of the removed measurement object,
All subsequent unit measurement time zones are assigned to each measurement target in the second target set as a rotation number.
The method of claim 1, comprising: Reassigning the unit measurement time zone of the removed measurement object,
Search the second target set for the measurement target with the maximum signal strength,
Assigning a plurality of subsequent unit measurement time zones of the removed measurement object to the measurement object having the maximum signal strength;
The method of claim 1, comprising: Sending a measurement report according to the monitoring status of the measurement report trigger event,
After the measurement report trigger event is monitored for the first measurement object, the first measurement report observation time Ttrig set by the serving base station is started for the first measurement object, and the first measurement report observation time Ttrig set in the Ttrig is started. Monitor over all unit measurement time slots assigned to one measurement object,
When the measurement report trigger event is monitored over all the unit measurement time periods, a measurement report is transmitted regarding the first measurement object after the end of the Ttrig.
11. A method according to claim 9 or claim 10 comprising: Sending a measurement report according to the monitoring status of the measurement report trigger event,
The second measurement report observation time Ttrig ′ is set as Ttrig ′ = Ttrig + (Nskip / 2) * Unit, where Ttrig is the first measurement report observation time set by the serving base station, and Nskip is The number of measurement objects removed,
After the measurement report trigger event is monitored for the first measurement object, the Ttrig 'is started for the first measurement object, and all unit measurements assigned to the first measurement object in the Ttrig' Monitor over time,
When the measurement report trigger event is monitored over all the unit measurement time periods, a measurement report is transmitted regarding the first measurement object after the end of Ttrig ′.
11. A method according to claim 9 or claim 10 comprising: Sending a measurement report according to the monitoring status of the measurement report trigger event,
The third measurement report observation time Ttrig ″ is set as Ttrig ″ = T1−mod (T1, Nkeep * Tunit), where T1 is the first measurement report observation time Ttrig or the second measurement report observation time. Ttrig ', Nkeep is the number of objects to be measured in the second object set,
After the measurement report trigger event is monitored for the first measurement object, the Ttrig '' is started for the first measurement object, and all the assigned to the first measurement object in the Ttrig '' Monitor over the unit measurement time zone,
When the measurement report trigger event is monitored over all the unit measurement time periods, a measurement report is transmitted regarding the first measurement object after the end of Ttrig ''.
The method of claim 12, comprising:   The method of claim 1, further comprising recovering the measurement of the signal strength of the removed measurement object if it is determined that a preset recovery condition is met. Determining that the preset recovery condition has been met is:
After removing the measurement object from the first object set, start measuring the removal time, and after the removal time is over, determine whether the current time is within one or more measurement report observation times, and any measurement If it is not within the report observation time, it is determined that a preset recovery condition has been met, or
After all measurement report observation times are over, determine that preset recovery conditions have been met, or
When the signal strength of the measurement target in the second target set is deteriorated, the second measurement target having the best signal strength is selected from the one or more removed measurement targets, and the recovery for the second measurement target is performed. Determine that the condition has been met,
The method of claim 14, comprising: Determining a first set of objects including the one or more measurement objects;
Receiving a measurement configuration provided from a serving base station, and determining the first target set according to one or more measurement targets specified in the measurement configuration;
The method according to any one of claims 1 to 5, claims 7 to 10, and claims 13 to 15. Determining a first set of objects including the one or more measurement objects;
The user terminal searches for a different carrier frequency or access method, and adds the searched carrier frequency or access method as a measurement target to the first target set.
The method according to any one of claims 1 to 5, claims 7 to 10, and claims 13 to 15. Determining a first set of objects including the one or more measurement objects;
The user terminal receives the measurement configuration provided from the serving base station, searches on a different carrier frequency or access scheme,
The first target set is determined by the measurement target specified by the measurement setting and the measurement target searched by the user terminal.
The method according to any one of claims 1 to 5, claims 7 to 10, and claims 13 to 15.   The carrier frequency used by the measurement target and the serving base station in the first target set is different, or the access method used by the measurement target and the serving base station in the first target set is different. The method of any one of Claims 1-5, Claims 7-10, and Claims 13-15. A user terminal,
A parameter storage unit for storing a first target set including one or a plurality of measurement objects and storing a correspondence relationship between the measurement objects and a single measurement time zone (Tunit);
Based on the correspondence between the measurement target stored in the parameter storage unit and the unit measurement time zone, the signal strength of each measurement target is measured, the measurement result is transmitted to the target control unit, and measured according to the monitoring status of the measurement report trigger event A measurement execution unit that sends a report;
A correspondence relationship between a measurement target and a unit measurement time zone is set, and one or more measurement targets are removed from the first target set according to a measurement result obtained by the measurement execution unit to obtain a second target set. A target control unit that reassigns the unit measurement time zone of the removed measurement target and updates the correspondence between the measurement target and the unit measurement time zone according to the reassignment result;
A user terminal comprising: The target control unit is:
A removal definition module to set the removal trigger event,
After the target removal trigger event is monitored in at least one unit measurement time zone of the measurement target in the first target set, the signal strength of the measurement target is measured in a plurality of subsequent unit measurement time zones of the measurement target. An object removal module to stop the measurement;
The user terminal according to claim 20, comprising:   The target removal module sets a target removal observation time, and after the target removal trigger event is monitored, starts the target removal observation time for a measurement target waiting for removal, and the removal within the target removal observation time. Monitoring over all unit measurement time zones assigned to the waiting measurement object, and if the target removal trigger event is monitored over all the unit measurement time zones, the removal waiting measurement is performed after the target removal observation time is over. The user terminal according to claim 21, wherein measurement for an object is stopped, and the removal-waiting measurement object is changed to a removed measurement object. The target control unit is:
And further including a Tunit assignment module that assigns all subsequent unit measurement time periods to each measurement object in the second object set by a rotation number.
The user terminal according to claim 21. The target control unit is:
The unit further includes a unit assignment module that searches for a measurement target having the maximum signal strength from the second target set, and assigns a plurality of subsequent unit measurement time zones of the removed measurement target to the measurement target having the maximum signal strength. ,
The user terminal according to claim 21. The target control unit is:
If it is determined that a preset recovery condition has been met, the method further comprises an object recovery module for recovering the measurement of the signal strength of the removed measurement object;
The user terminal according to any one of claims 20 to 24, wherein:   The parameter storage unit stores a measurement configuration provided from a serving base station, and the measurement configuration is for specifying a first target set including one or more measurement targets. The user terminal according to any one of claims 20 to 24.   The measurement execution unit further searches for a different carrier frequency or access method, and adds the searched carrier frequency or access method as a measurement target to the first target set stored in the parameter storage unit. The user terminal according to any one of claims 20 to 24.

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