WO2011120571A1

WO2011120571A1 - Stopping minimization of drive test measurement logging

Info

Publication number: WO2011120571A1
Application number: PCT/EP2010/054294
Authority: WO
Inventors: Malgorzata Tomala
Original assignee: Nokia Siemens Networks Oy
Current assignee: Nokia Solutions and Networks Oy
Priority date: 2010-03-31
Filing date: 2010-03-31
Publication date: 2011-10-06
Anticipated expiration: 2012-09-30

Abstract

It is provided an apparatus, comprising measuring means configured to perform a measurement of a radio parameter entity of a network; logging means configured to log the measurement; monitoring means configured to monitor a change of validity state of a system information of a radio resource control; and stopping means configured to stop the logging of the measurement based on the change of the validity state of the system information monitored by the monitoring means.

Description

DESCRIPTION

TITLE

Stopping minimization of drive test measurement logging

Field of the invention

The present invention relates to an apparatus, a method, a system, and a computer program product related to minimizing drive test measurements. More particularly, the present in^¬ vention relates to an apparatus, a method, a system, and a computer program product for stopping minimize drive test (MDT) measurement logging.

Background of the invention Minimizing drive tests (MDT) has been addressed in the long term evolution (LTE) standardization, in particular in 3^rd generation partnership project (3GPP) radio access networks (RAN) working group 2 (WG2) . The activity aims to define automatic collection of measurements performed by a user equipment (UE) , to enable easier monitoring of network performance and consequently to replace expensive drive-tests performed by operators dedicatedly. Since the functionality requires relevant input from the terminal, i.e. the user equipment, an involvement of the UEs is evident.

The MDT feature considers re-usage of the existing measure^¬ ments defined for typical mobility control and corresponding real-time reporting mode. However, the available means have been recognized as not sufficient to detect some network is- sues identified for e.g. coverage optimization, which is the prioritized MDT use case. E.g., idle mode mobility parameter settings and information about radio coverage when UE is idle are not possible to discover, whereas they are crucial for network dimensioning and planning.

Thus, a new approach in terms of measurement performance has been justified and introduced. Namely, the MDT has considered logging measurements and non-real time reporting mechanism and brought them into the LTE standard.

Therefore, the evaluation of the UE management is currently being investigated with regard to the newly introduced log^¬ ging functionality. In particular, a setting-up of the log- ging of MDT measurements in idle mode and non-real time re^¬ porting of the MDT measurements by the UE is addressed.

In document R2-100262 of 3GPP RAN WG2 two methods for set^¬ ting-up the logging of UE measurements for MDT in idle mode are proposed: one assumes the UE will be configured before entering idle state by a final RRC signalling, the second configuration involves broadcast signalling and assumes the UE will follow the configuration parameters periodically ac^¬ cording to the system information changes. Either solution has some pros and cons, thus needs to be further assessed in terms of technical viability.

Summary of the invention

It is an object of the present invention to improve the prior art . According to a first aspect of the invention, there is pro^¬ vided an apparatus, comprising measuring means configured to perform a measurement of a radio parameter entity of a net^¬ work; logging means configured to log the measurement; moni- toring means configured to monitor a change of validity state of a system information of a radio resource control; and stopping means configured to stop the logging of the measure^¬ ment based on the change of the validity state of the system information monitored by the monitoring means.

In the apparatus according to the first aspect, the change of the validity state may be at least one of a change of the system information and an expiry of a maximum validity period of the system information.

The apparatus according to the first aspect may further com^¬ prise first network monitoring means configured to monitor a first status of the network; and first number setting means configured to set a first defined number based on the first status, wherein the stopping means may be configured to stop the logging if the change of the validity state has occurred the first defined number of times.

The apparatus according to the first aspect may further com- prise second number setting means configured to set a second defined number based on a setting information received from the network, wherein the stopping means may be configured to stop the logging if the change of the validity state has oc^¬ curred the second defined number of times.

In the apparatus according to the first aspect, the radio pa^¬ rameter entity may comprise at least one of a common pilot channel received signal code power, a reference signal re- ceived power, a reference signal received quality, a location information, a time information, and a cell identification.

The apparatus according to the first aspect may further com- prise enabling means configured to enable a transmitting of the logged measurements when the apparatus is in a connected mode, in which at least one of radio resources, mobility, and a handover of the apparatus are controlled by the network. In the apparatus according to the first aspect, the stopping means may be configured to stop the logging only if the change of the validity state is caused by a change of a pre^¬ defined parameter contained in the system information, or if the maximum validity period of the system information is ex- pired.

According to a second aspect of the invention, there is pro^¬ vided an apparatus, comprising measuring processor configured to perform a measurement of a radio parameter entity of a network; logging processor configured to log the measurement; monitoring processor configured to monitor a change of valid^¬ ity state of a system information of a radio resource con^¬ trol; and stopping processor configured to stop the logging of the measurement based on the change of the validity state of the system information monitored by the monitoring proces^¬ sor .

In the apparatus according to the second aspect, the change of the validity state may be at least one of a change of the system information and an expiry of a maximum validity period of the system information.

The apparatus according to the second aspect may further com^¬ prise first network monitoring processor configured to moni- tor a first status of the network; and first number setting processor configured to set a first defined number based on the first status, wherein the stopping processor may be configured to stop the logging if the change of the validity state has occurred the first defined number of times.

The apparatus according to the second aspect may further com^¬ prise second number setting processor configured to set a second defined number based on a setting information received from the network, wherein the stopping processor may be configured to stop the logging if the change of the validity state has occurred the second defined number of times.

In the apparatus according to the second aspect, the radio parameter entity may comprise at least one of a common pilot channel received signal code power, a reference signal re^¬ ceived power, a reference signal received quality, a location information, a time information, and a cell identification. The apparatus according to the second aspect may further com^¬ prise enabling processor configured to enable a transmitting of the logged measurements when the apparatus is in a con^¬ nected mode, in which at least one of radio resources, mobil^¬ ity, and a handover of the apparatus are controlled by the network.

In the apparatus according to the second aspect, the stopping processor may be configured to stop the logging only if the change of the validity state is caused by a change of a pre- defined parameter contained in the system information, or if the maximum validity period of the system information is ex^¬ pired . The apparatus according to the first or second aspect may be an apparatus for stopping minimization of drive test measure^¬ ment logging. According to a third aspect of the invention, there is pro^¬ vided a user equipment comprising an apparatus according to the first or second aspect.

According to a fourth aspect of the invention, there is pro- vided a system, comprising a network element and an appara^¬ tus, wherein the network element comprises second network monitoring means configured to monitor a second status of the network, and defining means configured to define, based on the second status, a network setting information; and wherein the apparatus is an apparatus according to the first aspect comprising a second number setting means, and wherein the setting information is based on the network setting information . According to a fifth aspect of the invention, there is pro^¬ vided a system, comprising a network element and an apparatus, wherein the network element comprises second network monitoring processor configured to monitor a second status of the network, and defining processor configured to define, based on the second status, a network setting information; and wherein the apparatus comprises measuring processor configured to perform a measurement of a radio parameter entity of a network; logging processor configured to log the meas^¬ urement; monitoring processor configured to monitor a change of validity state of a system information of a radio resource control; stopping processor configured to stop the logging of the measurement based on the change of the validity state of the system information monitored by the monitoring processor, second number setting processor configured to set a second defined number based on the network setting information received from the network, wherein the stopping means is configured to stop the logging if the change of the validity state has occurred the second defined number of times.

The apparatus according to the fourth or fifth aspect may be different from the network element according to the respec^¬ tive aspect. The system according to the fourth or fifth aspect may be a system of stopping minimization of drive test measurement logging .

According to a sixth aspect of the invention, there is pro- vided a method, comprising performing, a measurement of a ra^¬ dio parameter entity of a network; logging the measurement; monitoring a change of a validity state of a system informa^¬ tion of a radio resource control; and stopping the logging of the measurement based on the change of the validity state of the system information.

The method of the sixth aspect may be a method of stopping minimization of drive test measurement logging. The method of the sixth aspect may be performed by an appara^¬ tus according to the first or second aspect.

In the method according to the sixth aspect, the change of the validity state may comprise at least one of a change of the system information and an expiry of a maximum validity period of the system information.

The method according to the sixth aspect may further comprise monitoring a first status of the network; and setting a first defined number based on the first status, wherein the logging may be stopped if the change of the validity state has oc^¬ curred the first defined number of times. The method according to the sixth aspect may further comprise setting a second defined number based on a setting informa^¬ tion received from the network, wherein the logging may be stopped if the change of the validity state has occurred the second defined number of times.

In the method according to the sixth aspect, the radio pa^¬ rameter entity may comprise at least one of a common pilot channel received signal code power, a reference signal re^¬ ceived power, a reference signal received quality, a location information, a time information, and a cell identification.

The method according to the sixth aspect may further comprise enabling a transmitting of the logged measurements when an apparatus performing the method is in a connected mode, in which at least one of radio resources, mobility, and a hand^¬ over of the apparatus are controlled by the network.

In the method according to the sixth aspect, the logging may be stopped only if the change of the validity state is caused by a change of a predefined parameter contained in the system information, or if the maximum validity period of the system information is expired.

In the method according to the sixth aspect, an apparatus performing the method may be comprised by a user equipment.

According to a seventh aspect of the invention, there is provided a method, comprising monitoring, by a network element of a network of an apparatus, a second status of the network, and defining, by the network based on the second status, a network setting information; and

performing, by the apparatus, a measurement of a radio pa^¬ rameter entity of a network; logging the measurement by the apparatus; monitoring, by the apparatus, a change of a valid^¬ ity state of a system information of a radio resource con^¬ trol; stopping, by the apparatus, the logging of the measure^¬ ment based on the change of the validity state of the system information; setting a second defined number based on the network setting information received from the network, wherein the logging is stopped if the change of the validity state has occurred the second defined number of times.

The method of the seventh aspect may be a method of stopping minimization of drive test measurement logging.

The apparatus according to the seventh aspect may be differ^¬ ent from the network element according to the seventh aspect. According to an eighth aspect of the invention, there is provided a computer program product, comprising computer- executable components which perform, when the program is run on a computer, the execution of which result in operations of the method according to any of the sixth and seventh aspects.

The computer program product according to the eighth aspect may be a computer program product, comprising computer- executable components which perform, when the program is run on a computer, the execution of which result in operations of performing a measurement of a radio parameter entity of a network; logging the measurement; monitoring a change of a validity state of a system information of a radio resource control; and stopping the logging of the measurement based on the change of the validity state of the system information. The computer program product according to the eighth aspect may be embodied as a computer-readable storage medium.

It is to be understood that any of the above modifications can be applied singly or in combination to the respective as^¬ pects to which they refer, unless they are explicitly stated as excluding alternatives.

Brief description of the drawings

Further details, features, objects, and advantages are appar^¬ ent from the following detailed description of the preferred embodiments of the present invention which is to be taken in conjunction with the appended drawings, wherein

Fig. 1 shows an apparatus according to an embodiment of the invention; and

Fig. 2 shows a method according to an embodiment of the in- vention.

Detailed description of certain embodiments

Herein below, certain embodiments of the present invention are described in detail with reference to the accompanying drawings, wherein the features of the embodiments can be freely combined with each other unless otherwise described. However, it is to be expressly understood that the descrip^¬ tion of certain embodiments is given for by way of example only, and that it is by no way intended to be understood as limiting the invention to the disclosed details. Moreover, it is to be understood that the apparatus is con^¬ figured to perform the corresponding method, although in some cases only the apparatus or only the method are described. Some embodiments of the invention are described below accord^¬ ing to a LTE system. However, other embodiments of the invention may belong to other radio communication systems.

While there are several approaches to configure MDT measure- ment logging in the idle mode, neither takes care of stopping the measurement except when the measurement campaign ends .

Here, logged MDT functionality means measuring and logging a radio parameter to transmit it to the network for later evaluation purposes. Starting and stopping MDT measurement logging means at least starting and stopping the logging, respectively, and may additionally mean starting and stopping the measurement itself. However, considering the requirement that idle mode services should be kept at a limited level, a mechanism to control and prevent long lasting operations is needed.

The invention targets to provide a trigger that may cease MDT logging active during idle state regardless of a way of con^¬ figuration .

In detail, for MDT purposes, the UE will be configured to perform the requested measurements in its idle state at the predefined trigger (s) and stores (logs) them until it enters from the idle mode into the connected mode. Here, idle mode means a mode, such as scanning of radio channels, registra^¬ tion UE ' s presence to the selected area, selection evalua^¬ tion, maintenance of a list of forbidden and allowed areas, cell reselection, initiation of the radio con^¬ nection, is done autonomously by the UE, whereas in the con^¬ nected mode, the radio resources, UE ' s mobility, or its hand^¬ overs are network controlled by its radio resource control. In the idle mode, MDT logs are not sent from the UE to the network .

The MDT measurements (example entities to be measured: CPICH RSCP, RSRP, RSRQ, location info, time info, cell identifica- tion) should be taken at the occurrence of a predefined trig^¬ ger, which can be a periodical or a failure event (e.g. peri^¬ odical trigger for downlink pilot measurements) . Thus, the recorded data can have a large extent and may affect user ex^¬ perience significantly.

Besides, it is required to store the measurement data (or at least those measurement data that should be reported to the network) in the UE memory. Accordingly, the processing has to be active during idle state. Consequently, the UE memory may reach the limit of its size and there is a risk that the es^¬ sential data (i.e. those data that are helpful to detect e.g. a coverage problem) will be discarded. In addition, sequence of operations lasting for an indefinite period of time is se^¬ vere in terms of battery life.

However, there is no mechanism to stop the logging or even the measurements if the measurements or their logging are not needed or if a user equipment is not capable to proceed any^¬ more .

Obviously, to prevent serious impacts, the UE may take some internal actions to stop the measurements or at least the logging. However, there is no guarantee that measured MDT data are not lost. Moreover, the decision made by the UE it- self without network awareness hinders the analysis of the reports obtained from the logged measurement data due to likely missing information. Furthermore, even in case the UE is capable to handle the logging operation (i.e. the MDT measurement and storing of the data) successfully, the reporting of the data or may cause the UE to transfer rather large amount of logged meas^¬ urement data. Thus, the anticipated signaling overhead for the following deferred reporting can be also intense and critical .

The conventional approach in 3GPP assumes that UE gathers MDT information based on the configuration the network has pro- vided, nothing has been mentioned for the configuration release (how long the logs are supposed to be recorded by the UE) . Unceasing collecting logs in the UE runs the risk of all the terminal aspects as mentioned earlier. In the result, there is no guarantee that the UE will manage to store the relevant data up to the nearest move to connected state.

Also, when one UE experiences problems, likely a number of UEs experience similar problems if they enter into the idle mode at that area. If, in such a case, too many UEs are con- figured to perform MDT measurements at the same time without any differentiation and possibility to cease logging, this may cause congestion and performance problems when these UEs report the logged measurement data to the network. According to the invention, it is proposed that the logging of the MDT measurement is stopped based on a change of a status of the system information. The system information (SI), is monitored by the UE in both the connected and the idle mode. Depending on the embodiment, in particular its radio access technology (RAT) , it may com^¬ prise information such as downlink system bandwidth, physical HARQ (hybrid adaptive repeat and request) indicator channel, system frame number; cell access related information, information for cell selection, a frequency band indicator, scheduling information, time division duplex configuration, SI window length, system information value tags; radio resource configuration information common to all UEs, cell-reselection information common for intra-frequency, inter-frequency, and/or inter-radio access technology cell reselection, speed dependent scaling parameters; neighbor cell related informa^¬ tion, information related to cell reselection to different radio access technologies; home eNodeB identifier; earthquake and tsunami warning system primary notification. The information may be grouped together into a master information block (MIB) and system information blocks (SIB) . As an example, SIB for LTE is described in H. Holma and A. Toskala, "LTE for UMTS"; Wiley & Sons Ltd., (2009), chapter 6.6.2, and in 3GPP specification 36.331 v9.10, section 5.2.

There are at least the following changes of the SI validity state: updated, i.e., when a new SI is received, and maximum validity period of SI expired. When SI is updated, this may be announced by a change notification ( systemlnfoValueTag in LTE) . In the idle mode, there is no possibility to stop MDT logging of a UE by the network. One might consider providing a special communication in the idle mode to allow a modification of MDT logging in the idle mode. However, such a special com- munication with a dedicated StopMDT command might have a huge impact on the architecture of the idle mode.

Through the use of a change of the validity state of the SI, no separate command to stop the MDT logging has to be intro^¬ duced. Accordingly, the communication between UE and network is simplified. In addition, since at least some of the RRC parameters (e.g. system information) are anyway monitored by the UE, even in idle mode, an UE according to embodiments of the invention may stop MDT logging even if it does not receive a dedicated MDT stop command for whatever reason.

In some embodiments, the UE ensures about having a valid ver^¬ sion of System Information anyway and will delete any stored system information after 3 hours from the moment it was confirmed to be valid. Thus, the fundamental assumption is the UE stops MDT measurement logging upon exceeding the maximum SI validity duration (i.e. 3 hours after the last update of SI), however is supposed to keep the recorded data until the first reporting possible occasion. The period of 3 hours is employed in some UEs of LTE, but this period may be different in other embodiments, in particular those belonging to another RAT. Furthermore, in some embodiments, in particular embodiments of UEs of LTE, the moment of the last update of SI to start the maximum validity period may be identified more precisely with the moment when the UE successfully con^¬ firms the SI .

An alternative approach may be applied if the UE is in a ra- dio environment more susceptible to System Information changes. It is a likely scenario that a UE in the area of MDT interest (i.e. with coverage problems) will be straying among cells and overwriting SI repeatedly. Since the UE applies the system information acquisition procedure upon re-selecting a cell or upon return from out of coverage, it may not meet the 3 hour validity restriction. In that case the validity of MDT configuration may be based on a predefined number of notifi^¬ cation changes or a number of notification changes that is adapted according to specific needs, such as the status of the network or specific parameters thereof.

The exact trigger to stop logging of MDT measurement in the idle mode (e.g. number of notification changes that release the corresponding MDT configuration) should be assessed to ensure the UE is not affected by MDT logging unnecessary for undefined period of time and on the other hand that recorded logs will provide sufficient feedback from the UE to figure out the problem in the network.

Fig. 1 shows an apparatus according to certain embodiments of the present invention. 50 denotes a measuring means, 60 de^¬ notes a logging means, 70 and 80 denote first and second monitoring means, and 90 denotes a stopping means. The meas- uring means 50 may be a measuring processor, the logging means 60 may be a logging processor, the first and second monitoring means 70 and 80 may be monitoring processors, and the stopping means 90 may be a stopping processor. The measuring means 50 is configured to perform one or more measurements that may be used as MDT measurement ( s ) . E.g., such a measurement may be performed by the UE independent on whether or not the MDT measurement is activated, or such a measurement may be performed only, when the MDT measurement is activated.

The MDT measurement is logged in the UE by logging means 60. The logging may be performed in a volatile or non-volatile memory of the UE, e.g. depending on the capabilities of the UE.

In the first and second monitoring means 70 and 80, it is monitored whether one of the stopping conditions for the log^¬ ging is fulfilled. In the embodiment according to Fig. 1, both monitoring means 70, 80 are directly connected to the logging means 60 and to the stopping means 90. In other embodiments, there may be a chain of first and second monitor- ing means 70, 80 between the logging means and the stopping means, wherein the sequence in the chain may be arbitrary. In such a chain, every monitoring means should be connected to the stopping means. Still furthermore, in some embodiments only one of the first and second monitoring means 70, 80 may be present, whereas in other embodiments, even more than these two monitoring means may be present. The monitoring means monitor whether or not a certain condition related to a validity change of the system information is fulfilled. Potential conditions are explained at greater detail hereinafter. The stopping means 90 is configured to stop the logging of the MDT measurement by the logging means 60 if at least one of the first and second monitoring means 70, 80 decides that a monitored condition is fulfilled. Fig. 2 shows a method according to the certain embodiments of the present invention.

According to step S50, a measurement of a radio parameter is performed. The measurement may be performed by the UE inde- pendent on whether or not MDT measurements are activated, or may be a special measurement for MDT purposes only.

In step S60, the measurement is logged by the logging means.

In step S70, it is checked, whether a condition for stopping the MDT measurement logging is fulfilled. In the present em^¬ bodiment, the condition is whether a certain time based on a maximum validity period of the system information has lapsed.

If the condition is fulfilled, the procedure goes forward to step S90, and the logging is stopped.

If the condition is not fulfilled, in step S80 another condi- tion for stopping the MDT measurement logging is checked. In the present embodiment, the condition is whether a certain number of system information changes since the triggering of the MDT measurement logging has occurred. If the condition is fulfilled, the procedure goes forward to step S90, and the logging is stopped.

If the condition is not fulfilled, the procedure goes back to the logging step S60 to log the next measurement data of the measuring step S50.

In some embodiments, if the condition of steps S70 and S80 are not fulfilled, the method may return to the measurement step S50, and if at least one of the conditions in steps S70 and S80 is fulfilled, the method may proceed to a step of stopping the performing of the measurement in addition to the stopping of logging in step S90. This embodiment is advanta^¬ geous if a measurement is started only for MDT measurement purposes . In some embodiments, the sequence of steps S70 and S80 may be interchanged or only one of these steps may be present. The method of Fig. 2 may be performed by the apparatus of Fig. 1.

In the following, certain embodiments of the present inven^¬ tion are explained at a greater detail:

The UE respects the configuration and performs MDT measure^¬ ments (including logging) ordered by the network it is attached to unless one of the restrictions is met:

- the SI validity timer (or its multiplication: X (X > 1) expires; i.e. the maximum validity period of the System

Information (SI) has lapsed;

- the SI is updated a predefined number Y (Y > 1) of

times. An update of the SI may be indicated by a notifi^¬ cation such as systemlnfoValueTag .

The very basic approach is to cease any predefined MDT con^¬ figuration when one of the conditions is fulfilled. In one embodiment, X and Y may be considered as constant predefined values .

In other embodiments, the X and/or Y value may be determined either by the UE, or by the network (e.g. evolved NodeB (eNB) or radio network controller (RNC) ) depending on the UE ' s capabilities, network situation, or certain problem that is to be discovered. Furthermore, if the UE is configured to deter^¬ mine the X and/or Y value, the value (s) may be easily trans^¬ ported as a part of MDT report to the network. On the other hand, if the network is configured to adapt these values, they may be easily transmitted to the UE together with the other MDT configuration data. The manner of X and Y determination may be done in a way to ease scheduled logging. Since the MDT configuration is broadcasted or signalled in the problematic area in terms of network coverage, it ad^¬ dresses UEs present in that region. Many affected UEs may re^¬ side in the area and in addition some may enter the connected mode rarely. For these UEs, monitoring of lapse of maximum SI validity period should be sufficient. Note that the lapse of the maximum validity period of the SI is measured from the last update of SI and not necessarily from the last update of the MDT configuration. On the other hand the configuration may affect UEs that sub^¬ sequently migrate in the area of interest or change the loca^¬ tion among several cells due to cells' boundary. Conse^¬ quently the UEs experience radio network resource changes (in particular SI changes) frequently in that region. Then, a reasonable value of system information changes should be used as a trigger to stop logging functionality in configured UEs to avoid unnecessary involvement of excessive number of de^¬ vices in this demanding area at the same time. In addition, the latter condition would get the best of devices that have been configured but move away from the area. In this particular case, only initial logging entries have a value that may be used in subsequent analyses. Anyhow, regardless of the selected criterion to stop the log^¬ ging of an MDT measurement, the merit of the solution is that UE measurement logs defined for MDT purposes are likely to be captured at the scheduled area, thus enable more efficient diagnosis of a certain problem. Furthermore, as the mechanism will be known to the UE and the eNB/RNC, it makes the functionality easier, in general and eases management of the logging functionality. In particular, it smoothes a way to manage the stored data, minimize its amount, avoid memory exhausting and battery drain, hence it helps to limit the end-user impact and avoid of implementa^¬ tion complexity in the UE .

In principle, the stopping of an MDT measurement logging based on changes of the validity state of the system informa^¬ tion is independent of the mechanism utilized for MDT meas^¬ urement logging configuration for UEs in the idle state. However, it should be noted that some alignment would have to be considered if broadcast configuration is chosen, hence MDT relevant SI may induce SI changes by itself.

The modules shown for the exemplary embodiments of Fig. 1 may be separate modules, or some or all of the modules may be im^¬ plemented in one module. The modules may be implemented in software, firmware, hardware, or a combination thereof.

The user equipment and/or the system according to an embodiment may be of the long term evolution (LTE) standard and, more particularly, of release 10 or a higher release of this standard.

In the exemplary embodiment, the MDT measurement logging is stopped based on the lapse of the maximum validity period of the system information or the number of the system informa- tion changes after triggering the MDT measurement logging.

In some embodiments, instead of observing a notification such as systemlnfoValueTag to detect an update of the SI, the UE may store a successfully confirmed SI and compare it regu^¬ larly with the current SI.

In some embodiments, instead of or in addition to the number of changes of the system information, the number of changes of one of the parameters contained in the system information and/or the number of changes of the master information block or a certain system information block may be monitored to stop the logging of MDT measurements. E.g., if an MDT meas^¬ urement logging is performed because of problems in intra-RAT handovers, changes of the system information related to in- ter-RAT handovers may not be taken into account for stopping the MDT measurement logging.

In some embodiments, the stopping may be based on only one a monitoring of the : aximum validity period of the SI or a number of changes of the SI after the triggering of the log ging .

In some embodiments storing (logging) of the measurement may mean storing of the raw data (i.e., measured data as they are) , while in other embodiments or for another measurement the data may be processed before storing, e.g. the data may be aggregated and/or normalized.

The invention is favourably usable in the idle mode, but it may be applied to the connected mode, too, if for some rea- son, some measurement reports should not be reported continu- ously to the network.

In some embodiments, together with stopping of the logging, some or all of the measurements, which are logged for the MDT feature, may be stopped, too. The condition to stop a MDT measurement logging may be based on the maximum validity period of the SI as in the example above. However, in some embodiments, instead of stopping the MDT measurement logging when the maximum validity period has lapsed for a certain number of times, the MDT measurement logging may only be stopped after another "after-period" of time has lapsed after the maximum validity period has lapsed for a certain number of times. The same may apply to the num^¬ ber of changes being a condition to stop. I.e., in some em- bodiments, the measurement logging may be continued for some time after the defined number of SI changes has occurred, e.g. for a predetermined "after-period" of time or for an "after-period" of time depending on some condition. In some embodiments, the "after-period" may depend on a status of the network, observed by the UE itself or by a network element and communicated to the UE .

According to the above description, it should thus be apparent that exemplary embodiments of the present invention pro- vide, for example a user equipment, or a component thereof, an apparatus embodying the same, a method for controlling and/or operating the same, and computer program (s) control^¬ ling and/or operating the same as well as mediums carrying such computer program (s) and forming computer program prod- uct ( s ) .

For example, described above are apparatuses, methods, a sys^¬ tem and computer program products capable of stopping logging an MDT measurement. In particular, it is provided an appara- tus, comprising measuring means configured to perform a measurement of a radio parameter entity of a network; logging means configured to log the measurement; monitoring means configured to monitor a change of validity state of a system information of a radio resource control; and stopping means configured to stop the logging of the measurement based on the change of the validity state of the system information monitored by the monitoring means. Implementations of any of the above described blocks, appara^¬ tuses, systems, techniques or methods include, as non limit^¬ ing examples, implementations as hardware, software, firm^¬ ware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

It is to be understood that what is described above is what is presently considered the preferred embodiments of the pre^¬ sent invention. However, it should be noted that the descrip- tion of the preferred embodiments is given by way of example only and that various modifications may be made without de^¬ parting from the scope of the invention as defined by the ap^¬ pended claims.

Claims

1. An apparatus, comprising

measuring means configured to perform a measurement of a radio parameter entity of a network;

logging means configured to log the measurement;

monitoring means configured to monitor a change of va^¬ lidity state of a system information of a radio resource con^¬ trol; and

stopping means configured to stop the logging of the measurement based on the change of the validity state of the system information monitored by the monitoring means.

2. The apparatus according to claim 1,

wherein the change of the validity state is at least one of a change of the system information and an expiry of a maximum validity period of the system information.

3. The apparatus according to any of claims 1 to 2, further comprising

first network monitoring means configured to monitor a first status of the network; and

first number setting means configured to set a first de^¬ fined number based on the first status,

wherein the stopping means is configured to stop the logging if the change of the validity state has occurred the first defined number of times.

4. The apparatus according to any of claims 1 to 2, further comprising

second number setting means configured to set a second defined number based on a setting information received from the network, wherein the stopping means is configured to stop the logging if the change of the validity state has occurred the second defined number of times.

5. The apparatus according to any of claims 1 to 4, wherein the radio parameter entity comprises at least one of a common pilot channel received signal code power, a reference signal received power, a reference signal received quality, a loca^¬ tion information, a time information, and a cell identifica- tion.

6. The apparatus according to any of claims 1 to 5, further comprising

enabling means configured to enable a transmitting of the logged measurements when the apparatus is in a connected mode, in which at least one of radio resources, mobility, and a handover of the apparatus are controlled by the network.

7. The apparatus according to any of claims 1 to 6, wherein the stopping means is configured to stop the logging only if the change of the validity state is caused by a change of a predefined parameter contained in the system information, or if the maximum validity period of the system information is expired .

8. A user equipment comprising an apparatus according to any of claims 1 to 7.

9. System, comprising

a network element and an apparatus, wherein the network element comprises

second network monitoring means configured to monitor a second status of the network, and defining means configured to define, based on the second status, a network setting information; and

wherein the apparatus is an apparatus according to claim 4 or any of claims 5 to 7 depending on claim 4, and wherein the setting information is based on the network setting information .

10. A method, comprising

performing a measurement of a radio parameter entity of a network;

logging the measurement;

monitoring a change of a validity state of a system in^¬ formation of a radio resource control; and

stopping the logging of the measurement based on the change of the validity state of the system information.

11. The method according to claim 10,

wherein the change of the validity state comprises at least one of a change of the system information and an expiry of a maximum validity period of the system information.

12. The method according to any of claims 10 to 11, further comprising

monitoring a first status of the network; and

setting a first defined number based on the first status ,

wherein the logging is stopped if the change of the va^¬ lidity state has occurred the first defined number of times.

13. The method according to any of claims 10 to 11, further comprising

setting a second defined number based on a setting information received from the network, wherein the logging is stopped if the change of the va^¬ lidity state has occurred the second defined number of times.

14. The method according to any of claims 10 to 13, wherein the radio parameter entity comprises at least one of a common pilot channel received signal code power, a reference signal received power, a reference signal received quality, a loca^¬ tion information, a time information, and a cell identification .

15. The method according to any of claims 10 to 14, further comprising

enabling a transmitting of the logged measurements when an apparatus performing the method is in a connected mode, in which at least one of radio resources, mobility, and a hand^¬ over of the apparatus are controlled by the network.

16. The method according to any of claims 10 to 15, wherein the logging is stopped only if the change of the validity state is caused by a change of a predefined parameter con^¬ tained in the system information, or if the maximum validity period of the system information is expired.

17. The method according to any of claims 10 to 16, wherein an apparatus performing the method is comprised by a user equipment .

18. Method, comprising

monitoring, by a network element of a network of an ap- paratus, a second status of the network, and

defining, by the network based on the second status, a network setting information; and performing the method according to claim 13 or any of claims 14 to 17 depending on claim 13, wherein the setting information is based on the network setting information.

19. Computer program product comprising computer-executable components which perform, when the program is run on a computer, the execution of which result in operations of the method according to any of claims 10 to 18.

20. The computer program product according to claim 19, embodied as a computer-readable storage medium.