WO2013050082A1

WO2013050082A1 - Measurement event reporting in cellular communications network

Info

Publication number: WO2013050082A1
Application number: PCT/EP2011/067547
Authority: WO
Inventors: Bernhard Wegmann; Ahmad AWADA; Ingo Viering
Original assignee: Nokia Siemens Networks Oy
Priority date: 2011-10-07
Filing date: 2011-10-07
Publication date: 2013-04-11
Also published as: EP2764725A1

Abstract

A cell-pair specific measurement event configuration is provided. A first cell-pair specific parameter is included in a first condition to be met for triggering a measurement event report by a user equipment in a cellular communications network (S31), wherein the first condition includes measurements concerning a serving cell of the user equipment, wherein a dedicated value of the first parameter depends on a neighboring cell of the serving cell, which is taken for triggering the measurement even report. Dedicated values of the first parameter are assigned for each neighboring cell of the serving cell (S32), and the assigned dedicated values are set in the cell-pair specific measurement event configuration (S33). For triggering the measurement event report, the user equipment derives conditions including the first condition and the dedicated value for the neighboring cell taken for triggering the measurement event report from the cell-pair specific measurement event configuration.

Description

MEASUREMENT EVENT REPORTING IN CELLULAR COMMUNICATIONS

NETWORK

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to mobile radio communications with focus on MRO as part of SON. In particular, the present invention relates to measurement event configuration in RRC domain for measurement event reporting in a cellular communications network with respect to intra- and inter-RAT mobility management.

Related background art

Prior art which is related to this technical field can e.g. be found in:

[1] 3GPP TS 36.331: "Evolved Universal Terrestrial Radio

Access (E-UTRA) ; Radio Resource Control (RRC) ; Protocol specification", Technical Specification.

[2] 3GPP TS 25.331: "Technical Specification Group Radio

Access Network; Radio Resource Control (RRC); Protocol specification", Technical Specification.

[3] US 2010/0197300 Al . The following meanings for the abbreviations used in this specification apply:

SON self optimizing network

MRO mobility robustness optimization

3GPP third generation partnership project

E-UTRA evolved universal terrestrial radio access

RLF radio link failure

HO handover

RCA root cause analysis

RAT radio access technology

LTE long term evolution

CIO cell individual offset

UE user equipment

KPI key performance indicator

RAN radio access network

eNB evolved node B

RSRP reference signal received power

RSRQ reference signal received quality

IE information element

ID identification

UMTS universal mobile telecommunications system

RF radio frequency

RRC radio resource control PCI physical cell ID

The target of MRO is to optimize network configuration parameters, e.g., HO trigger parameters, HO thresholds or timers, such that RLFs due to handovers are reduced. An HO is triggered by reported measurement events which in turn are triggered by neighboring and serving cell measurements .

Measurement events are either based on relative comparison of serving and neighboring cell signals where only a single offset parameter is specified for the event trigger or on two absolute thresholds where the first refers to the signal of the serving cell and the second to signal of the neighboring cell, i.e. two thresholds have to be fulfilled for triggering the measurement event .

These offsets or thresholds of the measurement events need to be specified cell-specific or even cell-pair specific.

Network planning normally starts with a network-wide uniform parameter configuration which is optimized cell individually in a second step by labor- and cost-intensive drive testing.

To avoid such labor- and cost-intensive drive testing, SON mechanisms, e.g. an MRO procedure, have been introduced for autonomous cell-specific optimization of cell-specific parameters . The MRO procedure includes two phases : an RCA phase, where cell or cell-pair specific KPI statistics are generated, and a correction phase, where measurement

parameters triggering an HO are adjusted.

For example, an LTE inter-RAT HO is triggered by the reported measurement event B2 which in turn is triggered when two conditions are fulfilled simultaneously as described in references [1] and [3] . An inter-RAT handover from an LTE cell to any 3G cell is triggered by the same handover parameters, i.e. the inter-RAT HO is triggered independently of cell border properties to different neighboring cells.

A corresponding inter-RAT handover trigger event in UTRAN is named 3A and is also a dual threshold event, i.e. it

comprises two conditions which have to be fulfilled as described in references [2] and [3] . The first condition of measurement event 3A which is related to the serving cell is cell-specific but independent of neighboring inter-RAT cells, and the second condition related to neighboring cell

measurements is triggered differently with respect to each cell of another RAT.

The same is true for an LTE-intra measurement event A5 (also a dual threshold event for intra-LTE measurements) which also comprises a cell individual offset component for the second condition related to neighboring cell measurements .

For the intra-RAT measurement event A3 as described in reference [1], where only a relative offset between target and source cell signal strengths is considered, it is implicitly possible to configure cell-pair handover

parameters by using a cell individual offset for the

neighboring cell.

The problem with the conventional measurement event

configuration is that a cell-pair specific configuration ability is not or only partly possible. SUMMARY OF THE INVENTION

The present invention aims at overcoming the above problem and providing a measurement event configuration enabling an improved network performance and avoiding a dead lock as a result of the MRO procedure.

This is achieved by the methods and apparatuses as defined in the appended claims . The invention may also be implemented by a computer program product .

According to an embodiment of the present invention, genuine cell-pair individual offsets for measurement events are allowed in a way that both serving and target cell related thresholds are individually adaptable for each cell pair. A genuine cell-pair specific configuration means that an offset of the serving cell can be different depending on a

neighboring cell of the serving cell.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a schematic diagram illustrating cells of a cellular communications network in which a street passes through an LTE coverage hole . Fig. 2 shows a schematic block diagram illustrating a structure of a network device according to an embodiment of the present invention.

Fig. 3 shows a flow chart illustrating a method of providing a measurement event configuration with cell-pair specific offsets for measurement events according to an embodiment of the invention.

Fig. 4 shows a flow chart illustrating a method of trigger a measurement event using a ce11-pair specific measurement event configuration according to an embodiment of the invention .

Fig. 5 shows a diagram illustrating an example of cell-pair specific thresholds for a dual threshold measurement event for triggering inter-RAT HO according to an embodiment of the invention .

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following embodiments of the invention will be described with reference to the accompanying drawings . It is to be noted that the invention is not coupled to a specific RAT or inter-RAT scenario. An LTE case or LTE-UMTS inter-RAT case may be considered, however, the invention can be applied to any RAT or INTER-RAT scenario. A cell border for each cell-pair, i.e., <Source cell, Target cell >, where either intra- or inter-RAT mobility is

performed, typically underlies different radio and mobility conditions, and therefore, needs different handover trigger parameters . For instance, it is assumed that there is a street between an LTE cell and a 3G-1 cell which passes through an LTE coverage hole as shown in Fig. 1. The radio conditions experienced by a UE moving on this street from the LTE cell to the 3G-1 cell are different from those of UEs leaving the LTE cell towards one of cells 3G-2 and 3G-3. When all the UEs handed over from the LTE cell are triggered with the same handover parameters independently to which cell the UE is going to be handed over, i.e. the LTE inter-RAT handover parameters are not set in a cell-pair specific manner, it is not possible to achieve optimal network performance. In other words, in case the same handover parameters are set for cell-pairs <LTE, 3G-1>, <LTE, 3G-2> and <LTE, 3G-3> shown in Fig. 1, the handovers towards 3G-2 and 3G-3 underlie the same conservative setting preventing from achieving better network performance.

In detail, a single common, target-cell independent handover parameter leads to the problem that MRO will achieve either a sort of best effort solution sacrificing the coverage of one RAT (LTE in Fig. 1) also towards the cell borders of the other cells (cells 3G-2 and 3G-3) or no solution at all (dead lock) if the root cause analysis yields two contradicting KPI results towards two different neighbor cells .

The handover from UMTS towards another RAT or an A5-triggered intra-LTE handover provides at least partial cell-pair specific configuration ability, namely a cell individual offset for neighboring cell measurements . However, if the threshold for a source (serving) cell measurement is fixed irrespective of a targeted neighboring cell measurement, even though radio conditions are varying within the source cell towards different neighboring cells, the flexibility to adapt the targeted neighboring cell measurement threshold is only suboptimal compared to a full-blown cell-pair specific configuration of measurement events including the own cell measurement .

As a preliminary matter before exploring details of various implementations, reference is made to Fig. 2 for illustrating a simplified block diagram of an electronic device suitable for use in practicing the exemplary embodiments of this invention.

A control unit 10 includes processing resources 11, memory resources 12 that may store a program, and interfaces 13 that may include a suitable RF transceiver coupled to one or more antennas (not shown) for bidirectional wireless

communications over one or more wireless links 5 with a control unit 20. The processing resources 11, memory resources 12 and interfaces 13 are coupled by a link 14.

The control unit 10 may be part of a cellular communications network, for example a base node of the cellular

communications network.

The control unit 20 includes processing resources 21, memory resources 22 that may store a program, and interfaces 23 that may include a suitable RF transceiver coupled to one or more antennas (not shown) for bidirectional wireless

communications over one or more wireless links 5 with the control unit 10. The processing resources 21, memory resources 22 and interfaces 23 are coupled by a link 24. The control unit 10 may be part of a user equipment.

The terms "connected, " "coupled, " or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be "connected" or "coupled" together by the use of one or more wires, cables and printed electrical

connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region and the optical (both visible and invisible) region, as non-limiting

examples .

At least one of the programs stored in the memory resources 12, 22 is assumed to include program instructions that, when executed by the associated processing resources, enable the control unit to operate in accordance with the exemplary embodiments of this invention, as detailed below. Inherent in the processing resources 11, 21 is a clock to enable

synchronism among the various apparatus for transmissions and receptions within the appropriate time intervals and slots required, as the scheduling grants and the granted

resources/subframes are time dependent. The transceivers include both transmitter and receiver, and inherent in each is a modulator/demodulator commonly known as a modem. The processing resources 11 also are assumed to each include a modem to facilitate communication over (hardwire) links which may be included in the interfaces 13 for communications between the control unit 10 and other network nodes.

In general, the exemplary embodiments of this invention may be implemented by computer software stored in the memory resources 12 and executable by the processing resources 11 the control unit 10, or by hardware, or by a combination of software and/or firmware and hardware in any or all of the devices shown.

In general, the control unit 20 may be applied in a UE which may comprise, but is not limited to, mobile stations, cellular telephones, personal digital assistants (PDAs) having wireless communication capabilities, portable

computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities,

Internet appliances permitting wireless Internet access and browsing, as well as portable units or terminals that incorporate combinations of such functions .

The memory resources 12 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The processing resources 11 may be of any type suitable to the local technica1 environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors and processors based on a multi-core processor architecture, as non-limiting examples.

As mentioned above, according to an embodiment of the invention, genuine cell-pair individual offsets (cell-pair specific parameters) for measurement events are provided in a way that both serving and target cell related thresholds are individually adaptable for each cell pair.

Fig. 3 shows a flowchart illustrating a method of providing a cell-pair specific measurement event configuration according to an embodiment of the invention .

In a step S31, a cell-pair specific parameter is included in a condition to be met for triggering report of a measurement event by a user equipment in a cellular communications network. The condition includes measurements concerning a serving cell which is a cell of the cellular communications network currently serving the user equipment, and a dedicated value of the first cell-pair specific parameter used for the first condition depends on a neighboring cell of the serving cell, which is taken for triggering the report of the measurement event . In a step S32, dedicated values of the cell-pair specific parameter for each neighboring cell of the serving cell are assigned .

In a step S33, the assigned dedicated values are set in the cell-pair specific measurement event configuration.

For example, the processing resources 11 using the memory resources 12 and interfaces 13 perform the inserting, assigning and setting of steps S31, S32 and S33.

The cell-pair specific parameter may be a first cell-pair specific parameter and the condition may be a first condition of an entering condition of a measurement event .

According to an embodiment of the invention, in addition to the first cell-pair specific parameter, a second cell-pair specific parameter may be included in a second condition to be met in addition to the first condition for triggering the report of the measurement event. The second condition includes measurements concerning the neighboring cell, and a dedicated value of the second cell-pair specific parameter used for the second condition depends on the serving cell and the neighboring cell . Dedicated values of the second cell- pair specific parameter for each neighboring cell of the serving cell are assigned and the assigned dedicated values are set in the cell-pair specific measurement event

configuration. For example, the processing resources 11 using the memory resources 12 and interfaces 13 perform the inserting, assigning and setting. The dedicated values of the first cell-pair specific

parameter and/or the second cell-pair specific parameter may be assigned for each cell of the cellular communications network as the serving cell, and the assigned dedicated values may be set in the cell-pair specific measurement event configuration. For example, the processing resources 11 using the memory resources 12 and interfaces 13 perform the assigning and setting.

The cell-pair specific measurement event configuration may be provided to user equipments for use with the cellular communications network. For example, the interfaces 13 perform the provision of the measurement event configuration, e.g. by transmitting it to the user equipments via the interfaces 13 through the link 5.

Referring to the flow chart shown in Fig. 4, a method of triggering report of a measurement event in a cellular communications network according to an embodiment of the invention is illustrated. For example, the method is

performed by the control unit 20 shown in Fig. 2.

In step S41, conditions of the measurement event are derived from a cell-pair specific measurement event configuration, which may have been received from the control unit 10 through the link 5 via the interfaces 23. The conditions are to be met for triggering the report of the measurement event. The conditions comprise a first condition including measurements concerning a serving cell which is a cell of the cellular communications network currently serving a user equipment and a first cell-pair specific parameter, wherein a dedicated value of the first cell-pair specific parameter used for the first condition depends on a neighboring cell of the serving cell, which is taken for triggering the report of the measurement event .

In step S42, the neighboring cell taken for triggering the report of the measurement event is determined.

In step S43, based on the determined neighboring cell, the dedicated value of the first cell-pair specific parameter is derived from the cell-pair specific measurement event configuration .

In step S44, measurements of the serving cell and the determined neighboring cell are conducted using the dedicated value of the first cell-pair specific parameter.

In step S45 it is checked whether the measurements meet the conditions. If the conditions are met (yes in step S45), in step S46 the measurement event is reported. If the conditions are not met (no in step S45), the process returns to step S44.

For example, the processing resources 21 using the memory resources 22 and interfaces 23 perform the operations of steps S41 to S46. The conditions may comprise a second condition including a second cell-pair specific parameter, wherein the second condition is to be met in addition to the first condition for triggering the report of the measurement event . The second condition includes measurements concerning the neighboring cell, wherein a dedicated value of the second cell-pair specific parameter used for the second condition depends on the serving cell and the neighboring cell. Based on the determined neighboring cell, the dedicated value of the second cell-pair specific parameter may be derived from the cell-pair specific measurement event configuration, the measurements of the serving cell and the determined

neighboring cell may be conducted using the dedicated value of the first cell-pair specific parameter and the dedicated value of the second cell-pair specific parameter, and when the measurements meet the conditions, the measurement event may be reported.

For example, the measurement report may be reported to the control unit 10 via the interfaces 23 through the link 5.

Deriving of data from the cell-pair specific measurement event configuration, measuring of quantities of the serving cell and the neighboring cell (conducting measurements) and reporting the measurement event may be carried out by the processing resources 21 using the memory resources 22 and interfaces 23.

The measurement event may be a dual threshold measurement event like 3A in UMTS and B2 in LTE, comprising two

conditions where the first condition is related the serving cell and the second condition to the neighboring cell, and the serving cell and the neighboring cell belong to different radio access technologies .

As shown in Fig. 5, the serving cell of the UE is cell 20 of RAT A, and the neighboring cell comprises cells 55, 56 and 57 of RAT B. A threshold Ts of the first condition is

configured cell-pair specific, and a threshold Tt of the second condition is configured cell-pair specific. That is, the threshold Ts comprises dedicated values for the cells 55, 56 and 57 expressed by Ts,55, Ts,56 and Ts,57, and the threshold Tt comprises dedicated values for the cells 55, 56 and 57 expressed by Tt,55, Tt,56 and Tt,57.

The measurement event may also be a dual threshold

measurement event like A5 in LTE, comprising two conditions where the first condition is related the serving cell and the second condition to the neighboring cell, and the serving cell and the neighboring cell belong to the same radio access technology.

The first cell-pair specific parameter may be an offset CIOl applied to a measured quantity of the serving cell depending on the neighboring cell taken for the second condition of the measurement event, and the second cell-pair specific parameter may be an offset CI02 applied to a measured quantity of the neighboring cell, wherein the measured quantity of the serving cell and the measure quantity of the neighboring cell are measured by the user equipment connected to the serving cell .

In the following, implementation examples will be given for cell-pair individual offsets (first/second cell-pair specific parameters) for measurement events B2, 3A, A5 and A3.

According to an implementation example 1, two dedicated offsets CIOl and CI02 (first and second cell-pair specific parameters) are included in an entering condition of

measurement event B2, both for serving and neighboring cell measurements .

According to implementation examples 2 and 3, an additional offset parameter R or T (first cell-pair specific parameter) is included in a first condition of measurement event 3A or A5, respectively.

Furthermore, according to an implementation example 4, in case of the measurement event A3 a dedicated cell-pair specific configuration is provided where a parameter Ocp of a serving cell is different depending on a neighboring cell of the serving cell.

Implementation Example 1 An entering condition of measurement event B2 is defined by equations (la) and (lb) (first and second conditions) :

(la) M_p + Hys + CI01_k,_j < B₂i && (lb) M_n + Of_n - Hys

CI02_k,_j > B₂₂

where

M_p is a measurement result of a serving cell not taking into account any offsets; M_n is a measurement result of a neighboring cell of different RAT, not taking into accounts any offsets;

Of_n is a frequency specific offset of the neighboring cell;

Hys is a hysteresis parameter for the measurement event B2;

B₂i is a first threshold parameter for the measurement event B2;

B₂₂ is a second threshold parameter for the measurement event B2;

CI01_k,_j is a first offset (first cell-pair specific

parameter) of the serving cell (serving cell k) with respect to the neighboring cell (neighboring cell j) of the different RAT; and

CI02_k;j is a second offset (second cell-pair specific

parameter) of the serving cell k with respect to the

neighboring cell j of the different RAT.

Implementation Example 2 An entering condition of measurement event 3A is defined by equations (2a) and (2b) (first and second conditions) :

(2a) Qused + Rk,j — Tused ^~~ ¾_a/2 && (2b) M_otherRAT + CI0_otherRAT ≥ T₀therRAT + ¾_a/2

where

Q_USe_d is a quality measurement of a serving UTRAN frequency;

T_USe_d is an absolute threshold that applies for the UTRAN system in that measurement;

H_3a is a hysteresis parameter for the measurement event 3A;

Mother_RAT is a measurement quantity for a neighboring cell of another system of different RAT;

CIOother_RAT is a cell individual offset for the neighboring cell;

Tother_RAT ίs an absolute threshold that is applied for the other system in the measurement; and

Rk,j is an offset (first cell-pair specific parameter) for the first condition 2a used by the serving cell (serving cell k) with respect to the neighboring cell (neighboring cell j) of the different RAT.

According to the implementation examples 1 and 2, by

introducing the offsets CIOl, CI02 for the first and second conditions (la) and (lb), and by introducing the offset R for the first condition (2a), a handover of a UE from one RAT to another is triggered differently depending on a target cell of the inter-RAT HO. Implementation Example 3

An entering condition of measurement event A5 is defined by equations (3a) and (3b) (first and second conditions) :

(3a) M_p + Hys + T_k;j < A5i && (3b) M_n + Of_n + Oc_n - Hys >

A5₂

where M_p is a measurement result of a serving cell not taking into account any offsets;

M_n is a measurement result of an intra-RAT neighboring cell, not taking into accounts any offsets;

Of_n is a frequency specific offset of the frequency of the intra-RAT neighboring cell;

Oc_n is a cell specific offset of the neighboring cell (i.e. celllndividualOffset as defined within measOb ectEUTRA corresponding to the frequency of the neighboring cell), and set to zero if not configured for the neighboring cell; Hys is a hysteresis parameter for the measurement event A5 ;

A5i is a first threshold parameter for the measurement event A5;

A5₂ is a second threshold parameter for the measurement event A5 ; and T_k;j is an offset for the first condition used by the serving cell (serving cell k) with respect to the neighboring cell (neighboring LTE cell j) . According to the implementation example 3, by introducing the offset T for the first condition (3a), a handover of a UE within a RAT is triggered differently depending on a target cell of the intra-RAT HO.

Implementation Example 4

An entering condition of measurement event A3 is defined by equation (4) (first and single condition) :

(4) Mn+Ofn+Ocn-Hys > Mp+Ofp+Ocp+Off

where

Mn is a measurement result of a neighboring cell, not taking into account any offsets;

Ofn is a frequency specific offset of the frequency of the neighboring cell;

Ocn is a cell specific offset of the neighboring cell, i.e. celllndividualOffset as defined within measOb ectEUTRA corresponding to the frequency of the neighboring cell;

Mp is a measurement result of a serving cell, not taking into account any offsets;

Ofp is a frequency specific offset of the primary frequency;

Ocp is a cell specific offset (first cell-pair specific parameter) of the (primary) serving cell with respect to the neighboring cell; Hys is a hysteresis parameter for the measurement event A3; and

Off is an offset parameter for the measurement event A3.

Mn and Mp are expressed in dBm in case of RSRP, or in dB in case of RSRQ.

Ofn, Ocn, Ofp, Ocp, Hys amd Off are expressed in dB . In this context it is noted that with introduction of carrier aggregation, parameter Ocs has been renamed to Ocp expressing that the measurement is related to a primary serving cell.

According to the implementation example 4, by making the offset Ocp for the condition (4) dependent on the neighboring cell, a handover of a UE within a RAT is triggered

differently depending on a target cell of the intra-RAT HO.

According to an embodiment of the invention, dedicated values of the above offsets are included in a measurement object field of a measurement event configuration, thereby

generating a eel 1-pair specific measurement event

configuration. For each PC I of a neighboring cell of a

(different) RAT, an offset value of CIOl, CI02, R, T or Ocp may be assigned.

With introducing a more detailed cell-pair specific

measurement configuration as described above, based on MRO an improved network performance can be achieved. According to an aspect of the invention, an apparatus for providing a cell-pair specific measurement event

configuration is provided, which comprises means for

including a first cell-pair specific parameter in a first condition to be met for triggering report of a measurement event by a user equipment in a cellular communications network, wherein the first condition includes measurements concerning a serving cell which is a cell of the cellular communications network currently serving the user equipment, wherein a dedicated value of the first cell-pair specific parameter used for the first condition depends on a

neighboring cell of the serving cell, which is taken for triggering the report of the measurement event, means for assigning dedicated values of the first cell-pair specific parameter for each neighboring cell of the serving cell, and means for setting the assigned dedicated values in the cell- pair specific measurement event configuration.

The apparatus may comprise the control unit 10 shown in Fig. 2, and the including means, assigning means and setting means may be implemented by the processing resources 11 which may use the memory resources 12 and interfaces 13 for the above including, assigning and setting.

The including means may include a second cell-pair specific parameter in a second condition to be met in addition to the first condition for triggering the report of the measurement event, wherein the second condition includes measurements concerning the neighboring cell, wherein a dedicated value of the second cell-pair specific parameter used for the second condition depends on the serving cell and the neighboring cell, the assiging means may assign dedicated values of the second cell-pair specific parameter for each neighboring cell of the serving cell, and the setting means may set the assigned dedicated values in the cell-pair specific

measurement event configuration.

The measurement event may be a dual threshold measurement event comprising two conditions where the first condition is related the serving cell and the second condition to the neighboring cell, and the serving cell and the neighboring cell belong to different radio access technologies .

The measurement event may also be a dual threshold

measurement event comprising two conditions where the first condition is related to the serving cell and the second condition to the neighboring cell, and the serving cell and the neighboring cell belong to the same radio access

technology .

The first cell-pair specific parameter may be an offset CIOl applied to a measured quantity of the serving cell depending on the neighboring cell taken for the second condition of the measurement event, and the second cell-pair specific

parameter may be an offset CI02 applied to a measured quantity of the neighboring cell, wherein the measured quantity of the serving cell and the measure quantity of the neighboring cell are measured by the user equipment connected to the serving cell .

The assigning means may assign the dedicated values of the first cell-pair specific parameter and/or the second cell- pair specific parameter for each cell of the cellular communications network as the serving cell, and the setting means may set the assigned dedicated values in the cell-pair specific measurement event configuration.

The apparatus may comprise means for providing the cell-pair specific measurement event configuration to user equipments for use with the cellular communications network. The apparatus may comprise the control unit 10, and the providin means may be implemented by the processing resources 11 whic may use the memory resources 12 and interfaces 13 as well as the link 5, for example, for the above providing.

According to an aspect of the invention, an apparatus for triggering report of a measurement event in a cellular communications network is provided, which comprises means for deriving conditions of the measurement event from a cell-pair specific measurement event configuration, which are to be met for triggering report of the measurement event by a user equipment in the cellular communications network, wherein the conditions comprise a first condition including measurements concerning a serving cell which is a cell of the cellular communications network currently serving the user equipment and a first cell-pair specific parameter, wherein a dedicated value of the first cell-pair specific parameter used for the first condition depends on a neighboring cell of the serving cell, which is taken for triggering the report of the measurement event, means for determining the neighboring cell taken for triggering the report of the measurement event, wherein based on the determined neighboring cell, the deriving means derive the dedicated value of the first cell- pair specific parameter from the cell-pair specific measurement event configuration, means for conducting measurements of the serving cell and the determined

neighboring cell using the dedicated value of the first cell- pair specific parameter, and means for, when the measurements meet the conditions, reporting the measurement event.

The apparatus may comprise the control unit 20, and the deriving means, determining means, measurement conducting means and reporting means may be implemented by the

processing resources 21 which may use the memory resources 22 and interfaces 23 as well as the link 5, for example, for the above deriving, determining, measurement conducting and reporting .

The conditions may comprise a second condition including a second cell-pair specific parameter, wherein the second condition is to be met in addition to the first condition for triggering the report of the measurement event, wherein the second condition includes measurements concerning the neighboring cell, wherein a dedicated value of the second cell-pair specific parameter used for the second condition depends on the serving cell and the neighboring cell, wherein the deriving means, based on the determined neighboring cell, derive the dedicated value of the second cell-pair specific parameter from the cell-pair specific measurement event configuration, the measurement conducting means conduct the measurements of the serving cell and the determined

neighboring cell using the dedicated value of the first cell- pair specific parameter and the dedicated value of the second cell-pair specific parameter, and the reporting means, when the measurements meet the conditions, report the measurement event . The measurement event may be a dual threshold measurement event comprising two conditions where the first condition related the serving cell and the second condition to the neighboring cell, and the serving cell and the neighboring cell belong to different radio access technologies .

The measurement event may also be a dual threshold

technology .

The measurement event may a dual threshold measurement event, the measurement conducting means may measure a quantity of the serving cell and a quantity of the neighboring cell, the first cell-pair specific parameter may be an offset CIOl applied to the measured quantity of the serving cell

depending on the neighboring cell taken for the second condition of the measurement event, and the second cell-pair specific parameter may be an offset CI02 applied to the measured quantity of the neighboring cell.

According to an aspect of the invention, a cell-pair specific measurement event configuration is provided. A first cell- pair specific parameter is included in a first condition to be met for triggering a measurement event report by a user equipment in a cellular communications network, wherein the first condition includes measurements concerning a serving cell of the user equipment, wherein a dedicated value of the first parameter depends on a neighboring cell of the serving cell, which is taken for triggering the measurement even report. Dedicated values of the first parameter are assigned for each neighboring cell of the serving cell, and the assigned dedicated values are set in the cell-pair specific measurement event configuration. For triggering the

measurement event report, the user equipment derives conditions including the first condition and the dedicated value for the neighboring cell taken for triggering the measurement event report from the cell-pair specific measurement event configuration.

It is to be understood that the above de scription is illustrative of the invention and is not to be construed as limiting the invention. Various modifications and

applications may occur to those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims .

Claims

CLAIMS :

1. A method of providing a cell-pair specific measurement event configuration, the method comprising: including a first cell-pair specific parameter in a first condition to be met for triggering report of a

measurement event by a user equipment in a cellular

communications network, wherein the first condition includes measurements concerning a serving cell which is a cell of the cellular communications network currently serving the user equipment, wherein a dedicated value of the first cell-pair specific parameter used for the first condition depends on a neighboring cell of the serving cell, which is taken for triggering the report of the measurement event; assigning dedicated values of the first cell-pair specific parameter for each neighboring cell of the serving cell; and setting the assigned dedicated values in the cell-pair specific measurement event configuration.

2. The method of claim 1, further comprising: including a second cell-pair specific parameter in a second condition to be met in addition to the first condition for triggering the report of the measurement event, wherein the second condition includes measurements concerning the neighboring cell, wherein a dedicated value of the second cell-pair specific parameter used for the second condition depends on the serving cell and the neighboring cell; assigning dedicated values of the second cell-pair specific parameter for each neighboring cell of the serving cell; and setting the assigned dedicated values in the cell-pair specific measurement event configuration.

3. The method of claim 2, wherein the measurement event is a dual threshold measurement event comprising two conditions where the first condition is related to the serving cell and the second condition to the neighboring cell, and the serving cell and the neighboring cell belong to different radio access technologies.

4. The method of claim 2, wherein the measurement event is a dual threshold measurement event comprising two conditions where the first condition is related to the serving cell and the second condition to the neighboring cell, and the serving cell and the neighboring cell belong to the same radio access technology .

5. The method of any one of claims 2 to 4, wherein the first cell-pair specific parameter is an offset CIOl applied to a measured quantity of the serving cell depending on the neighboring cell taken for the second condition of the measurement event , the second cell-pair specific parameter is an offset CI02 applied to a measured quantity of the neighboring cell, wherein the measured quantity of the serving cell and the measured quantity of the neighboring cell are measured by the user equipment connected to the serving cell.

6. The method of any one of claims 1 to 5, comprising: assigning the dedicated values of the first cell-pair specific parameter and/or the second cell-pair specific parameter for each cell of the cellular communications network as the serving cell; and setting the assigned dedicated values in the cell-pair specific measurement event configuration.

7. The method of any one of claims 1 to 6, comprising: providing the cell-pair specific measurement event configuration to user equipments for use with the cellular communications network.

8. A method of triggering report of a measurement event in a cellular communications network, the method comprising: deriving conditions of the measurement event from a cell-pair specific measurement event configuration, which are to be met for triggering report of the measurement event by a user equipment in the cellular communications network, wherein the conditions comprise a first condition including measurements concerning a serving cell which is a cell of the cellular communications network currently serving the user equipment and a first cell-pair specific parameter, wherein a dedicated value of the first cell-pair specific parameter used for the first condition depends on a neighboring cell of the serving cell, which is taken for triggering the report of the measurement event; determining the neighboring cell taken for triggering the report of the measurement event; based on the determined neighboring cell, deriving the dedicated value of the first cell-pair specific parameter from the cell-pair specific measurement event configuration; conducting measurements of the serving cell and the determined neighboring cell using the dedicated value of the first cell-pair specific parameter; and when the measurements meet the conditions, reporting the measurement event .

9. The method of claim 8, wherein the conditions comprise a second condition including a second cell-pair specific parameter, wherein the second condition is to be met in addition to the first condition for triggering the report of the measurement event, wherein the second condition includes measurements concerning the neighboring cell, wherein a dedicated value of the second cell-pair specific parameter used for the second condition depends on the serving cell and the neighboring cell, the method comprising: based on the determined neighboring cell, deriving the dedicated value of the second cell-pair specific parameter from the cell-pair specific measurement event configuration; conducting the measurements of the serving cell and the determined neighboring cell using the dedicated value of the first cell-pair specific parameter and the dedicated value of the second cell-pair specific parameter; and when the measurements meet the conditions, reporting the measurement event .

10. The method of claim 9, wherein the measurement event is a dual threshold measurement event, the first cell-pair specific parameter is an offset CIOl applied to a measured quantity of the serving cell depending on the neighboring cell taken for the second condition of the measurement event, and the second cell-pair specific parameter is an offset CI02 applied to a measured quantity of the neighboring cell, wherein the measured quantity of the serving cell and the measured quantity of the neighboring cell are measured by the user equipment connected to the serving cell.

11. A computer program product including a program for a processing device, comprising software code portions for performing the steps of any one of claims 1 to 10 when the program is run on the processing device.

12. The computer program product according to claim 11, wherein the computer program product comprises a computer- readable medium on which the software code portions are stored.

13. The computer program product according to claim 11, wherein the program is directly loadable into an internal memory of the processing device.

14. A control unit for providing a cell-pair specific measurement event configuration, the control unit being configured to: include a first cell-pair specific parameter in a first condition to be met for triggering report of a measurement event by a user equipment in a cellular communications network, wherein the first condition includes measurements concerning a serving cell which is a cell of the cellular communications network currently serving the user equipment, wherein a dedicated value of the first cell-pair specific parameter used for the first condition depends on a

neighboring cell of the serving cell, which is taken for triggering the report of the measurement event; assign dedicated values of the first cell-pair specific parameter for each neighboring cell of the serving cell; and set the assigned dedicated values in the cell-pair specific measurement event configuration.

15. The control unit of claim 14, configured to: include a second cell-pair specific parameter in a second condition to be met in addition to the first condition for triggering the report of the measurement event, wherein the second condition includes measurements concerning the neighboring cell, wherein a dedicated value of the second cell-pair specific parameter used for the second condition depends on the serving cell and the neighboring cell; assign dedicated values of the second cell-pair specific parameter for each neighboring cell of the serving cell; and set the assigned dedicated values in the cell-pair specific measurement event configuration.

16. The control unit of claim 14 or 15, configured to: assign the dedicated values of the first cell-pair specific parameter and/or the second cell-pair specific parameter for each cell of the cellular communications network as the serving cell; and set the assigned dedicated values in the cell-pair specific measurement event configuration.

17. The control unit of any one of claims 14 to 16,

configured to: provide the cell-pair specific measurement event configuration to user equipments for use with the cellular communications network.

18. A control unit for triggering report of a measurement event in a cellular communications network, the control unit being configured to: derive conditions of the measurement event from a cell- pair specific measurement event configuration, which are to be met for triggering report of the measurement event by a user equipment in the cellular communications network, wherein the conditions comprise a first condition including measurements concerning a serving cell which is a cell of the cellular communications network currently serving the user equipment and a first cell-pair specific parameter, wherein a dedicated value of the first cell-pair specific parameter used for the first condition depends on a neighboring cell of the serving cell, which is taken for triggering the report of the measurement event; determine the neighboring cell taken for triggering the report of the measurement event; based on the determined neighboring cell, derive the dedicated value of the first cell-pair specific parameter from the cell-pair specific measurement event configuration; conduct measurements of the serving cell and the determined neighboring cell using the dedicated value of the first cell-pair specific parameter; and when the measurements meet the conditions, report the measurement event .

19. The control unit of claim 18, wherein the conditions comprise a second condition including a second cell-pair specific parameter, wherein the second condition is to be met in addition to the first condition for triggering the report of the measurement event, wherein the second condition includes measurements concerning the neighboring cell, wherein a dedicated value of the second cell-pair specific parameter used for the second condition depends on the serving cell and the neighboring cell, the control unit being configured to: based on the determined neighboring cell, derive the dedicated value of the second cell-pair specific parameter from the cell-pair specific measurement event configuration; conduct the measurements of the serving cell and the determined neighboring cell using the dedicated value of the first cell-pair specific parameter and the dedicated value of the second cell-pair specific parameter; and when the measurements meet the conditions, report the measurement event.

20. The control unit of claim 19, wherein the measurement event is a dual threshold measurement event, wherein the control unit is configured to measure a quantity of the serving cell and a quantity of the neighboring cell, wherein the first cell-pair specific parameter is an offset CIOl applied to the measured quantity of the serving cell depending on the neighboring cell taken for the second condition of the measurement event, and the second cell-pair specific parameter is an offset CI02 applied to the measured quantity of the neighboring cell.