WO2010063328A1

WO2010063328A1 - Controlling transmit power

Info

Publication number: WO2010063328A1
Application number: PCT/EP2008/066939
Authority: WO
Inventors: Markus Dillinger; Hanns Jürgen SCHWARZBAUER
Original assignee: Nokia Siemens Networks Oy
Priority date: 2008-12-05
Filing date: 2008-12-05
Publication date: 2010-06-10

Abstract

A network apparatus (200) for wireless communication is described. The network apparatus comprises a cell detecting device (206) and a reading device (209). The cell detecting device (206) is adapted for detecting a hidden cell mode. The reading device (209) is adapted for reading at least one power correction value if the cell detecting device (206) has detected the hidden cell mode. The cell detecting device (206) is further adapted for correcting at least one power value of the network apparatus based on the at least one power correction value.

Description

Controlling Transmit Power

Technical field of the invention

The present invention relates to the technical field of communication networks. In particular the present invention relates to a network apparatus for wireless communication, to a recording carrier having a data structure, to a controlling apparatus for the network apparatus, to a method for correcting at least one power value of a network apparatus, to a program element for correcting at least one power value of a network apparatus and to a computer-readable medium for correcting at least one power value of a network apparatus.

Background of the invention

The mass employment of cellular phones or mobile phones may make people to increase using their cellular phones in areas which may have been predominated for fixed line communication. For example, people may use their cellular phones at their home location instead of using the fixed telecommunication devices, which may coexist at the home location with the mobile phone. A reason for using the cellular phone at home might be that some people may primarily use their cellular phones and thus contact data and address data may be stored in the phone books of the cellular phones. Thus, for some people it may be more comfortable to use these databases to contact a called party instead of updating the telephone books of the fixed line telephones.

Tariff models of network operators may make it also attractive for people instead of paying for and maintaining two different communication medias, to only maintain a single communication media. Thus, in some households the fixed line may be replaced by wireless access. In order to support using of mobile phones at predefined locations, such as at a home location or inside a shop, it may have to be considered that a home base station, for example a femto base station, may have to coexist with a macro base station from a network operator. In such cases the femto base station and the macro base station may use the same carrier frequency. A femto base station or a femto may scan the macro environment and may adapt the maximum transmission power of the femto to an interference situation.

The macro environment may be a physical environment influenced by a macro cell, for example caused by a radiation of an electromagnetic wave transmitted by a macro base station. The macro environment may depend on physical parameters, such as the line of sight, the building density and the physical structure of the country such as concrete, grass or trees. An interference situation may arise if a user equipment or a mobile terminal may communicate with a femto base station and the physical signals used for this communication may interfere with the physical signals used by the macro base station.

Scanning the macro environment by the femto base station and adapting the maximum transmission power of the femto to the interference situation may be a regular operation.

From the document WO 2008/076219 A2 a method of communicating in a pico cell within a macro cell may be known, wherein the method may comprise the steps of determining an allowable interference from a pico cell mobile station to the macro cell, determining a path-loss between the mobile station and the macro cell and determining an uplink transmit power of the mobile station for communicating in the pico cell based upon the determined allowable interference and the determined path-loss.

The 3GPP document TS 32.642, "3rd Generation Partnership Project (3GPP) ; Technical Specification Group Services and System Aspects; Telecommunication management; Configuration Management (CM) ; UTRAN (UMTS Terrestrial Radio Access Network) network resources Integration Reference Point (IRP) : Network Resource Model (NRM)", v. 8.2.0, 2008-06-19, Release 8, may specify the protocol neutral UTRAN Network Resources IRP.

The 3GPP document TS 25.433, "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; UTRAN Iub interface Node B Application Part (NBAP) signalling", v 8.2.0, 2008-09-26, Release 8, may specify the radio network layer signalling protocol called Node B Application Part (NBAP) specification to be used for Control Plane over Iub Interface.

The 3GPP document TS 25.331, "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC) ; Protocol Specification", v 8.4.0, 2008-09-23, Release 8, may specify the Radio Resource Control protocol for the UE-UTRAN radio interface.

There may be a need to provide a more efficient employment of a Base Station, in particular of a femto base station, within at least a part of a macro environment.

Summary of the invention

According to an exemplary embodiment of the present invention, a network apparatus for wireless communication, a recording carrier having a data structure, a controlling apparatus for the network apparatus, a method for correcting at least one power value of a network apparatus, a program element and a computer-readable medium may be provided.

According to an exemplary embodiment of the present invention, a network apparatus for wireless communication may be provided. In an example the network apparatus may comprise a cell detecting device and a reading device. The cell detecting device may be adapted for detecting a hidden cell mode, an insulation mode or an isolation mode of the network apparatus. A hidden cell mode may be a mode or state, in which mode the network apparatus may substantially not see any macro base station or in which mode the network apparatus may be substantially isolated from the macro base station.

In an example, the reading device may be adapted for reading at least one power correction value when the cell detecting device may have detected the hidden cell mode. The detecting device may be further adapted for correcting at least one power value of the network apparatus based on the at least one power correction value. Thus, a predefined power correction value may be used for reducing the transmit power of at least one of the network apparatus and the user equipment connected to the network apparatus .

According to another exemplary embodiment of the present invention, a recording carrier having a data structure may be provided. The data structure may comprise at least one power correction value at a predefined position of the data structure, such that a reading device can access the correction value, if a hidden cell mode may have been detected.

In an example the data structure may comprise two power correction values, one for the network apparatus and the other for a user equipment connected to the network apparatus .

A recording carrier may be a floppy disk, a harddisk, an USB

(Universal Serial Bus) storage device, a memory, a RAM

(Random Access Memory) , a ROM (Read Only Memory) , a flash memory and/or an EPROM (Erasable Programmable Read Only Memory) . Thus, the recording carrier may be a computer- readable medium which may be structured by using a predefined data structure or a data model, which predefined data structure may allow a reading device and/or a writing device to access values or parameters for controlling a network apparatus such that power values can be adapted to a determined mode, to a scanned mode, to an environmental situation, to a regulatory requirement or to a predefined state. The data structure may be an address scheme for the recording carrier which may allow for quickly finding relevant information in the recording carrier.

In an example the data structure may be the data model of the network apparatus.

According to another exemplary embodiment of the present invention, a controlling apparatus for a network apparatus may be provided. The controlling apparatus in an example may comprise a reading device, which may be adapted for reading at least one power correction value on request of a network apparatus. The reading device may access a recording carrier for reading the power correction value.

In a further example the controlling apparatus may comprise a writing device for writing values or parameters in the data structure .

According to yet another exemplary embodiment of the present invention, a method for correcting at least one power value of the network apparatus may be provided. The method may comprise detecting a hidden cell mode of the network apparatus, reading a power correction value if the hidden cell mode may have been detected and correcting at least one power value of the network apparatus. The at least one power value of the network apparatus in an example may be corrected based on the at least one power correction value.

According to yet another exemplary embodiment of the present invention, a program element may be provided, which when being executed by a processor may be adapted to carry out the method for correcting at least one power value of a network apparatus . In an example a computer-readable medium may be provided, which may comprise a program code, which program code may be adapted when being executed by a processor to carry out the method for correcting at least one power value of a network apparatus .

Generally correcting may also mean adapting or adjusting and may not be restricted to wrong values.

A data structure may be a definition of the structure of a recording carrier or of a computer readable medium. In an example the data structure may be an object model which model may be used to describe the data structure. The data structure may be a collection of parameters or values which parameters can be stored in registers or memory units associated with a corresponding object. Thus, the data structure may be a map or an address scheme for a recording carrier supporting a reading device and/or a writing device in finding values on the recording carrier.

There may exist radio technologies, such as WLAN (Wireless Local Area Network) , which may use a shared radio frequency band for example the ISM-band (Industrial, Scientific, and Medical Band) . In such a shared band interference may be accepted.

However, for example in GSM (Global System for Mobile communication) , UMTS (Universal Mobile Telecommunication System) and/or SAE/LTE (System Architecture Evolution/Long- Term Evolution) the frequency bands may be administrated by a central regulator, such as the Federal Network Agency, Bundesnetzagentur, the REGTP (Regulierungsbehδrde fur Telekommunikation und Post) , the FCC (Federal Communications Commission) . In an example, an operator may pay for using a predefined frequency band. Therefore, the regulator may want to control the use of frequencies. A femto base station may scan the environment for a macro cell or a macro environment and the femto base station may adapt the maximum transmission power of the femto base station or of a UE to the interference situation. However, when a femto base station may not be able to scan the surrounding macro cells, to scan the macro environment, to detect or to determine any neighbours, the femto may not be able to determine an interference situation. A femto may not be able to scan a macro environment or the macro cell, if the femto base station may be deployed inside a building. A macro cell may at least partially surround the femto base station, i.e. the femto cell generated by the femto base station may overlap with a macro cell generated by a macro base station.

In particular a femto base station may not be able to determine a macro cell or a macro base station, which may generate the macro cell, if the femto base station may be employed in a garage or inside a building. Such a scenario, situation or mode may be a hidden mode or a hidden situation. In other words detecting a hidden situation may make the femto base station to switch in a hidden mode.

A hidden mode may either be a mode where a femto base station may not be able to detect a surrounding macro cell by scanning the macro cell. The femto base station may be hidden, if the femto base station may not be able to scan, detect, listen to or determine an external macro base station which may use the same carrier frequency as the femto base station .

In the above example, where a femto base station may be employed in a garage or in an underground garage, it may be possible that a macro base station, which may be employed above ground or on the surface, may not be seen by the femto base station in the underground garage. For example, a field strength generated from a macro base station may be attenuated such that the field strength received at the femto base station may be below a predefined threshold. Thus the femto base station may not realize or may not sense that a macro base station may exist in the neighbourship of the femto base station and that the macro base station may work on the same frequency.

However, if the femto base station may be employed in the underground garage and the macro base station may be employed surface or over ground of the underground garage a situation may exist where a mobile terminal, a mobile phone or a user equipment (UE) may have direct line of sight to the macro base station over ground and to the femto base station underground. However, the femto base station may not see the macro base station. Generally, an underground garage may be a hidden place for installing the femto base station.

However, the femto base station may not know about the existence of the macro base station. The femto base station may be able to control respectively regulate the transmit power (TX power) of the user equipment. Thus, the femto base station may instruct or control the UE such that a maximum transmit power may be used between the femto base station and the UE. However, using a maximum power on the same frequency or in the same frequency band or in at least a part of the same frequency band that may be used by the macro base station may interfere the macro base station and may interfere other connections between other user terminals or UEs and the macro base station.

UEs attached to such a hidden femto may harm an uplink receiver, a receiver in the uplink of a macro base station or a receiver of the macro base station. Controlling a UE with a femto without having knowledge about the macro base station may generate a strong impairment of the macro network. This may in particular be true, if femto base stations may be installed by common people who may not be very experienced or trained with radio planning of a radio network. Regulators may ask for protection mechanism in order to prevent such interference between partially or complete overlapping femto cells and macro cells.

A femto base station may use a femto data model. A femto data model may be a data structure, which may allow storing parameters for controlling a femto base station. A femto data model stored on a record carrier may allow influencing the functionality of the femto base station. The data structure may allow structuring the record carrier. The data structure and at least values stored in the data structure may represent a status or may represent the functional behaviour of the femto base station. In particular the data structure may be a structure which may allow a reading device and/or a writing device of the femto base station to access predefined values at predefined positions or at predefined addresses. A reading device and/or a writing device may be combined in an input/output device. In an example the data structure may allow to administrate a recording carrier or a computer- readable medium. Therefore, the data model or the data structure may allow a coding or a functional storing of data in order to control the network apparatus.

The data model may be enhanced or extended by at least one parameter which may allow reacting on a hidden base station scenario. In other words, an existing data model may be enhanced by additional further parameters, which may substantially only be valid when a femto base station may not see any macro base station. Thus, the additional parameters or the additional at least one parameter may substantially only be valid when the femto base station may generate an isolated cell or may be a hidden femto base station.

Thus, an aspect of the present invention may be in a case where the femto base station may not be sure about the environment, to use a failsafe configuration in order to prevent to interfere with a potentially existing macro base station. The failsafe parameters for the transmit power may be stored in a data structure as at least one power correction value.

This at least one parameter may allow to reduce or to correct the maximum femto base station transmitting power and/or the maximum user equipment transmission power which may be used during a regular operation. A regular operation may be an operation where the femto base station may see the macro base station and wherein the femto base station may adapt the maximum transmission power of the femto base station to an interference situation. For example, the maximum transmission power may be reduced.

In an example, additionally two parameters may be employed in the data model or in the data structure. Thus, the data structure or the data model may comprise at least two parameters which may be used in a hidden mode of the femto base station. The hidden mode of the femto base station may be a mode, where the femto base station may scan for a macro base station and may not detect or may not determine a macro base station existing in the environment of the femto base station. In particular a power level received from a macro base station may be below a threshold. Such a low poer level or such a poor power level may make the femto base station believe that there may be no macro base station in the neighbourship of the femto base station.

In an example there may be additional two parameters defined by a mobile operator which may allow fulfilling regulatory requirements or regulatory demands of a regulator such as the Federal Network Agency or the FCC. The at least one additional parameter may allow preventing that the femto base station may have to be switched off when a hidden situation or a hidden mode or an isolated cell may have been detected. A regulator may require switching off a femto base station if a hidden mode may be detected in order to prevent that interference on a common frequency may appear. The additional at least one parameter could be stored in the femto base station, in the femto gateway or in an OMS (Operation and Maintenance System) . The additional at least one parameter may be downloaded to the femto from the femto gateway or from the OMS, when the femto base station may determine a hidden mode of the femto base station.

Thus, a data model comprising at least one parameter for reducing an output power may allow providing an interference reduction mechanism for hidden femto cells.

The at least one parameter may allow reducing parameter values of the data model. In an example a parameter may exist which may allow to reduce all HNB (Home NodeB) Tx (Transmit) related power values. Generally the Tx power of a base station such as a HNB, a Node B, a BTS (Base Transceiver Station) , an eNB (enhanced Node B) or a WiMAX™ (Worldwide Interoperability for Microwave Access) base station may be reduced.

In another example a further parameter may exist which may allow to reduce all UE (User Equipment) TX related power values of the data model.

Thus, interference impairments of hidden femtos to surrounding macro cells may be reduced. Therefore, regulatory demands may be able to be fulfilled without switching off the femto .

Thus HNB output power interference may be handled by trying to detect a macro cell within the HNB or within the femto.

In an example the HNB may apply different TX power levels if no macro cell may be detected, if a detection level may be poor or if the detection level may be below a threshold. The detection level may be a level of a measured power received from a macro base station. A poor detection level may be a detection level which may allow determining the presence of a signal, which may however not allow detecting a corresponding macro cell. In an example a UE transmit power level may be controlled by means of signalling from the access point, from the FAP or from the femto base station to the UE.

In an example a new maximum transmit power limit may be transmitted to the UE. In another example a signal may be sent to the UE indicating a special situation such as "no macro cell was detected". If the special situation may have been indicated, the UE may only react with limiting the right UE TX power. If the maximum transmit power limit may have been transmitted to the UE, the UE may use the received maximum transmit power to limit the UE transmit power.

In another example, the UE may adapt the power to the new limit according to the signalled parameter.

According to another exemplary embodiment of the present invention, the reading device may be adapted for reading the at least one power correction value from a predefined position in a data structure. The position may be a storage cell or a register of a memory device, of a storage device or of a recording carrier.

A data structure or a data model may allow a reading device and/or writing device to find predetermined values at predetermined positions. For example, an address structure may allow the reading device to find a position in a storage device or in a memory, in order to read values for functionally influencing the behaviour of the network apparatus .

The data model may be an object oriented data model.

According to another exemplary embodiment of the present invention, the data structure may be stored in at least one storing device selected from the group of storing devices consisting of a record carrier, an internal record carrier inside the FAP, an external record carrier outside the FAP, a gateway apparatus, a femto gateway apparatus, a network storing device, a server, an operation and maintenance system (OMS), a computer-readable medium and a database.

The storing device may allow storing parameters or values agreed by a regulatory authority and may support the network apparatus to find the correct behaviour in a case where no macro cell may have been detected when the femto base station may scan for the macro base station.

In an example, an internal record carrier having the data structure or the data model may allow quickly accessing the parameters .

For example, an external record carrier may allow reducing the manufacturing cost of a femto base station and may allow storing corresponding parameters on a central place within the network. Thus an external record carrier may be used by a plurality of femto base stations.

An internal record carrier and / or an external record carrier may comprise an input/output device, for configuring the values, e.g. the regulatory threshold values, in the data structure of the record carrier. The input/output device may use the reading device for reading the corresponding values. Furthermore, in an example the network apparatus and / or the controlling apparatus may comprise a writing device, which may be adapted for writing values in the data structure at predefined locations.

According to yet another exemplary embodiment of the present invention, the at least one power value to be corrected by the at least one power correction value may be a power value selected from the group of power values consisting of a MaxTxPower value (Maximum Transmit Power value) , P- CpichPowerConfig value (Primary Common Control Channel Power Configuration value) , a P-CpichPowerAutoConfigEnable value (Primary Common Control Channel Power Automatic Configuration

Enable value) , a P-CpichPowerlnUse value (Primary Common

Control Channel Power InUse value) , a PrimaryCpichTxPower value (Primary Common Control Channel Transmit Power value) , a UeTxPwrMaxRach value (User Equipment Transmit Power Maximum

Random Access Channel value) , a ConstantValue value (Constatn

Value) , a MaxHNBTxPower value (Maximum Home NodeB Transmit

Power value) and a MaxULTxPower (Maximum Up Link Transmit

Power) . In an example the at least one power value may be an integer power value.

Thus, the selection of such values may allow influencing at least a group of network apparatus values, such as MaxTxPower value, P-CpichPowerConfig value, P-CpichPowerAutoConfigEnable value, P-CpichPowerlnUse value, Primary CpichTxPower value, Constant value and MaxHNBTxPower value.

In another example this may allow to select User Equipment power values, for example the UeTxPwrMaxRach value and/or the MaxULTxPower value. Thus, in an example a group of HNB related power values and/or a group of UE related power values or UL related power levels may be influenced.

In an example, all members of the group the same correction values may be applied.

According to another exemplary embodiment of the present invention, the at least one power correction value may be at least one value of a "HNBTxPower values HIDDEN" value and a "MaxULTxPower HIDDEN" value.

Thus, at least two values or two values for the Hidden mode may be provided. The HNBTx Power values HIDDEN value may reduce an HNBTxPower, a selection of HNBTxPower values or all HNBTxPower values. The MaxULTxPower HIDDEN value may provide a value which may allow to reduce a single UeTxPower value, a group of UeTxPower values, UE Tx related power values, UL Tx related power values or all UeTxPower values within the data model .

The group of HNB Tx related power values may comprise the MaxTxPower value, the P-CpichPowerConfig value, the P- CpichPowerAutoConfigEnable value, the P-CpichPowerlnuse value, the PrimaryCpichTxPower value, the ConstantValue value and the MaxHNBTxPower value.

The group of UE Tx related power values may comprise the UeTxPwrMaxRach value and the MaxULTxPower .

In an example every single power value of the data model of the femto base station may have an individually associated power correction value for the hidden mode. Thus, different correction values for the different power values may be provided.

In another example, values for HNB may be values for a down link and UL values may be values for a up link. Thus, power in the hidden mode may be controlled individually for up link and down link.

Thus, if the result of scanning may be that no macro base station may be available, a percental power reduction of corresponding values may be conducted.

According to yet another exemplary embodiment of the present invention, the network apparatus may be at least one network apparatus selected from the group of network apparatuses consisting of a base station, a femto base station, a pico base station, a NodeB, an eNB, a WiMax™ base station and a Home NodeB.

According to another exemplary embodiment of the present invention, correcting the at least one power value of the network apparatus may comprise multiplying the at least one power value with the at least one power correction value. Multiplying with a correction value may allow reducing the power values, a group of power values, a selection of power values or at least all power values by the same factor, which may allow to quickly reducing the power values when a hidden mode may have been detected.

According to yet another exemplary embodiment of the present invention, detecting the hidden cell mode or the hidden mode or a hidden femto base station may comprise at least one of detecting a detection level below a threshold, an isolation of the network apparatus from a macro cell and detecting missing beacon.

In an example a macro base station may generate on a regular basis a beacon on a beacon channel, on a broadcast channel

(BCH) or on a common control channel. If this beacon or pattern may be detected, a femto base station may realize that a macro base station may exist close to the femto base station. However, if the signal strength of the beacon or of any other signal sent by the macro base station may be below a predefined threshold value or below a detectable value, a hidden cell mode may be detected or may be assumed.

According to another exemplary embodiment of the present invention, the reading device of the controlling device may be adapted for reading the at least one power correction value from a predefined position in a data structure or in a data model.

In an example the reading device of the controlling apparatus may be a reading device which can also be employed in the network apparatus. Deploying the reading device and the controlling apparatus may allow a central storing of the parameters.

In an example the computer-readable medium may be a floppy disk, a harddisk, a USB storage device, a RAM, a ROM or an EPROM. A computer-readable medium may also be a data communication network, e.g. the internet which may allow downloading a program code.

It has also to be noted that exemplary embodiments of the present invention and aspects of the invention have been described with reference to different subject-matters. In particular, some embodiments have been described with reference to apparatus type claims whereas other embodiments have been described with reference to method type claims. However, a person skilled in the art will gather from the above and the following description that unless other notified in addition to any combination between features belonging to one type of subject-matter also any combination between features relating to different subject-matters in particular between features of the apparatus claims and the features of the method claims may be considered to be disclosed with this application.

These and other aspects of the present invention will become apparent from and elucidated with reference to the embodiments described hereinafter.

Exemplary embodiments of the present invention will be described in the following with reference to the following drawings .

Brief description of the drawings

Fig. 1 shows a block diagram of a data model for a femto access point for a better understanding of the present invention .

Fig. 2 shows a block diagram of a network apparatus according to an exemplary embodiment of the present invention. Fig. 3 shows a block diagram of a controlling apparatus according to an exemplary embodiment of the present invention .

Fig. 4 shows a flow diagram for a method for correcting at least one power value according to an exemplary embodiment of the present invention.

Detailed description

The illustration in the drawings is schematic. In different drawings, similar or identical elements are provided with the same reference numerals.

The block diagram of the data structure or the data model shows the top level object for a Femto Access Point (FAP) . FAPService . { i } . 100. The top level object 100 comprises a control object group 101, a configuration object group 102 and a monitoring and management object group 103.

The control object group comprises the . FAPService .{ i }. FAPDevice . Description . object, which comprises parameters relating to the general description of the FAP device.

Furthermore the control object group comprises the .FAPService. {i} . FAPDeviceCapabilities . object 105, which comprises parameters relating to the hardware compatibilities of the FAP device.

Furthermore the control object group 101 comprises the object .FAPService. {i} .FAPControl. UMTS. 106, which comprise parameters relating to the UMTS system specific information. The control object group 101 may further comprise the

. FAPService . { i } . AccessMgmt . object 107 which comprise parameters relating to Access Management (ACL, CSG, LIA)

(Access Control List, Closed Subscriber Group, Local IP (Internet Protocol) Access) .

The configuration object group 102 comprises the . FAPService .{ i }. CellConfig. object which comprises parameters relating to configuring the FAP. One object of the CellConfig object is the UMTS object 109.

The configuration object group 102 further comprises the . FAPService { i }. Transport . object 110 comprising the sub- objects Tunnel. Ill, Real-time. 112, Security. 113 and VPN. (Virtual Private Network) 114.

The configuration object group 102 further comprises the . FAP .{ i }. Timing. object 115 which contains parameters relating to timing, for example the NTP. object 116 (Network Time Protocol) or the GPS. object 117 (Global Positioning System) .

The monitoring and management object group comprises the . FAPService .{ i } .REM. object which comprise parameters relating to REM (Radio Environment Measurement) 118.

The REM object 118 comprises the WCDMAFddRem. object 119 (Wideband Code-Division Multiple Access Frequency Division Duplex REM) which comprise parameters relating to radio environment measurement capabilities for the UMTS system.

Furthermore, the REM 118 object comprises the GSMRem. object

120 (Global System for Mobile Communications REM) which contains parameters relating to GSM REM capabilities.

The REM object furthermore comprises the AutoConfig. object

121 (Auto Configuration) and the GPS. object 122. The GPS. object contains parameters relating to the location of the FAP derived by the embedded GPS receiver in the FAP.

Furthermore the monitoring and management object group 103 comprises the . FAPService { i } . ServiceEvents . object 123, which contains parameters relating to service events.

The ServiceEvents. object 123 comprises the Management, object 124, the ActiveEvents . object 125, the History, object 126 and the pending Delivery, object 127.

An extract from a femto data model which covers substantially all transmission power related parameters for a femto access point and for an UE attached to a femto access point or a femto base station may be shown in table Tab. 1.

Tab. 1

P- Boolean Indicates whether the CpichPowerConfig HNB supports the auto- configuration capability to determine the P-CPICH power .

True: the HNB has this capability. The HMS may provide a range of minimum and maximum values for the HNB to select from.

False: the HNB does not have this capability. The HMS needs to provide a specific maximum value for the HNB as upperbound.

UeTxPwrMaxRach Int[-50:33] W Maximum TX power level an UE may use when accessing the cell on RACH. This value is used for cell (re- ) selection by calculating Pcompensation : max (UE_TXPWR_MAX_RACH

P_MAX, 0), where UE_TXPWR_MAX_RACH is this parameter and P_MAX is the max Tx power that a UE can transmit .

Integer (-50..33) , unit in dBm

Ref : 25.331, sec.10.3.2.3, 25.304, sec.5.2.3

Table Tab. 1 shows in the first column the name of an object, parameter or variable, in the second column the type, in the third column Tab. 1 indicates whether the variable can be written, in the forth column a description is provided and in the last column the object default is provided. Enabling writing of a value may allow configuring the FAP.

The extract from the femto data model shows substantially only parameters which may be used to control a transmit power of the femto base station or of an UE.

The parameter MaxTxPower may be an unsigned integer value and indicates the maximum possible transmit power which the FAP hardware can support. The value of the maximum transmit power is provided in dBm (Decibel related to Milliwatt) . The MaxTxPower parameter is part of the .FAPService. {i} . FAPDevice . Capabilities . object.

The P-CpichPowerConfig parameter (Primary Common Pilot Channel Power Config) may be a Boolean value which can have the values true or false. This value indicates whether the HNB (Home NodeB) or femto base station supports the auto- configuration capability to determine the P-Cpich power. This parameter is true if the HNB has the auto-configuration capability to determine the P-Cpich power. The HMS (Home NodeB Management System) may provide a range of minimum and maximum values for the HNB to select from.

HMS may be a NMS (Network management system) . OMS may be an element manager of the femto base station.

The P-CpichPowerConfig value may be false if the HNB does not have the auto-configuration capability to determine the P- CpichPower. A HMS needs to provide a specific maximum value for the HNB as anupper bound.

The P-CpichPowerConfig value may be part of the .FAPService. {i} . FAPDevice . Capabilities .UMTS .AutoConfig. object .

A further parameter relating to the power of the FAP is the Boolean value P-CpichPowerAutoConfigEnable value which can be written. This value indicates whether the auto-configuration capability and the HNB is used or not to determine the P- Cpich power. Thus, this value may indicate that self configuration of the femto base station may be allowed. The femto base station may use the power correction values and/or the femto base station may scan for a macro base station if this value is set. The P-CpichPowerAutoConfigEnable value may be true if the HMS enables the HNB' s auto-configuration capability. It is false, if the HMS disables the HNB' s auto- configuration capability. The HMS will provide a specific value to be used. The power correction value may influence the integer power values and may not influence the Boolean power values.

The P-CpichPowerAutoconfigEnable value as well as the P- CpichPowerlnUse value are part of the .FAPService. {i} . FAPControl .UMTS . Autoconfig. object.

The P-CpichPowerlnUse value may be an integer value ranging from -100 to +500. The P-Cpich power currently used by the HNB is indicated by this value. If the HNB' s auto- configuration capability is used to configure the UARFCN (UMTS Absolute Radio Frequency Channel Number) , this parameter indicates the values selected by the HNB among the range provided.

If the auto-configuration capability is not used, then this parameter contains the same value with the one specified by the HMS.

The

.FAPService. {i} . CellConfig. UMTS .RAN. FDDHNB .NeighbourList . Inte rFreqCell . { i } object comprises table containing the inter- frequency cell list. This object may comprise the PrimaryCpichChTxPower value which is an integer value ranging from -100 to 500. The primary CpichChTxPower comprises the primary CPICH Tx Power in dBm. The actual power is calculated by dividing the value of the primary CpichCh Tx power value by 10. Thus this parameter ranges from -10.0 to +50.0 in steps of 0.1 dB . The unit of the primary CpichChTxPower is dBm.

The .FAPService. {i} .CellConfig. UMTS. RAN. FDDHNB object contains parameter relating to the cell level configuration for FDD (Frequency Division Duplex) mode Home NodeB (HNB) . This object may comprise a further power-related parameter which is a user equipment related power value, or the UeTxPwrMaxRach. This power value is an integer value ranging from -50 to 33 and can be written. The UeTxPwrMaxRach (User Equipment Transmit Power Maximum Random Access Channel) indicates the maximum transmit power level a UE may use when accessing the cell on RACH (Random Access Channel) . This value is used for cell (re-) selection by calculating Pcompensation which may be the maximum of the UE_TXPWR_MAX_RACH value minus the P_MAX value and zero. This may prevent a negative power value. The UE_TXPWR_MAX_RACH is the value of UeTxPwrMaxRach and P MAX is the maximum transmit power that a UE can transmit. The unit of this parameter is dBm.

The parameter ConstantValue and the parameter UeTxPwrMaxRach are part of the object .FAPService. {i} . CellConfig. UMTS .RAN. FDDHNB . This object contains parameters relating to the cell-level configuration for FDD mode HNB.

The parameter ConstantValue is an integer value which ranges from -35 to -10 and can be written. The constant value is used by the UE to calculate the initial output power on PRACH

(Physical RACH) according to the open loop power control procedure. This is in SIB5 (System Information Block 5) . The

SIB5 may be used by a base station to inform the UE about the maximum allowed power. The unit of constant value is dB

(Decibel) .

The .FAPService. {i} .CellConfig. UMTS. RAN. FDDHNB. RF. object contains parameters relating to the RF (Radio Frequency) configuration. This parameter comprises the two power-related values MaxHNBTxPower and MaxULTxPower .

The MaxHNBTxPower value is an integer value ranging from 0 to 500 and can be written. This parameter indicates the maximum transmission power allowed to the HNB, the maximum value for the linear sum of the power of all downlink physical channels, that is allowed to be used in a cell. The linear sum may be the sum of all power values of a channel in Watt (W) and/or the sum of power values in dB .

The actual power is calculated by the MaxHNBTxPower value divided by 10. The MaxHNBTxPower value is provided in a unit of the dBm in steps of 0.1 dB .

The MaxULTxPower value ranges from -50 to 33 and can be written. The MaxULTxPower value is the maximum transmission power level a UE can use on PRACH. The unit of MaxULTxPower is dBm.

All the values shown in table Tab. 1 or at least a group of these values can be influenced by additional parameters or by correcting parameters which may also be part of the data model. These two parameters are shown in table Tab. 2.

Tab. 2

Table Tab. 2 shows power correcting values. A power correcting value for the HNB Tx related values is the HNB Tx Power values HIDDEN. The HNB Tx Power values HIDDEN is an integer value ranging from 0 to 100. The HNB Tx Power values HIDDEN value is used to reduce a group or all HNB Tx related power values, when no macro scan results are available at the femto location. The values 0 to 100 are percentages or percents, i.e. the value may range from 0 to 1. Thus the regular Tx values which are multiplied with the HNB Tx Power values HIDDEN value are reduced. In an example the HNB Tx Power values HIDDEN may be an attenuation for the output power of the HNB or the FAP.

It may exist only one single power correction value, which may be valid for all uplink and downlink power values. It may also exist a power correction value associated with every single power value, which may allow individually adapting every single power value.

An additional value may exist for User Equipment related Tx power. The MaxULTxPower HIDDEN value ranges from 0 to 100 and may be adapted to reduce a portion or all of the Ue Tx related power values when no macro scan results are available at a femto location. The MaxULTxPower Hidden values represent percentages. Therefore, also the MaxULTxPower HIDDEN values may be an attenuation for UeTxPower values. The power in the uplink (UL) may be set or controlled by the UE.

The HNBTxPower values HIDDEN value and/or the MaxULTxPower HIDDEN value may be used if a hidden mode of the femto base station has been detected. The correction values may be used independently from another. The value stored in the HNBTxPower values HIDDEN parameter and/or in the MaxULTxPower HIDDEN value may be multiplied by the corresponding Tx value. The HNBTxPower values HIDDEN thus may relate to the MaxTxPower, the P-CpichPowerlnUse, the PrimaryCpichTxPower, the ConstantValue and the MaxHNBTxPower value. Thus, HNBTxPower values HIDDEN may relate to at least one integer power value for the down link.

The MaxULTxPower HIDDEN value may be used for the UeTxPwrMaxRach and for the MaxULTxPower value. Thus, MaxULTxPower HIDDEN may relate to at least one integer power value for the up link.

This may result in an attenuation value or damping value for corresponding output power either of the HNB and/or of the UE.

Thus, the Home NodeB (HNB) and/or the femto access point

(FAP) which detects a Hidden mode or which detects that no macro cell is available reduce its output power and signal a specific output power limitation for a UE, which communicates with the femto access point.

The two correction parameters HNBTxPower values HIDDEN and/or MaxULTxPower HIDDEN may be added to the data model. In an example an additional object of the data model may be defined for a reduced operation or for the hidden mode. This additional object, e.g. the isolated operation object, may comprise at least one of a power correction value. In an example the isolated operation object may comprise the HNBTxPower values HIDDEN value and/or MaxULTxPower HIDDEN value.

Thus, interference of a femto cell to macro cells can be controlled in the special situation, that no macro cell has been detected.

A FAP can scan for macro cells and determine maximum power based on the macro cell measurements. In the case that no macro cell has been detected an access point may not have to be switched off. Instead of switching off the access point may operate with reduced power.

Therefore, the HNB is trying to detect macro cells by scanning for macro cells.

A HNB may apply different Tx power levels if no macro cells are detected or detection level is poor or the detection is below a threshold.

In addition or alternatively to restricting HNB output power levels, an UE Tx power level can be restricted by signalling a new maximum transmit power limit to the UE or by signalling information that in a predefined cell no macro cell was detected by the access point. The UE then adapts the power to the new limit according to the signal parameter.

The HNB can scan for the macro cells on a regular basis and as soon as a macro cell is detected, the power output can be adapted to prevent an interference situation.

Thus, a femto access point which has not detected a macro cell may not have to be switched off. This may increase the acceptability of femto access points and may allow to distribute a femto access point to common people for installing the access point.

Fig. 2 shows a block diagram of a network node or of a femto access point according to an exemplary embodiment of the present invention.

The network node 200 or femto access point 200 comprises the antenna 201. The antenna 201 may be used to communicate with a user equipment, not shown in Fig. 2. The femto access point 200 further comprises the sending and receiving device 202 which is connected to the antenna 201. The bidirectional links 203 and 204 connect the sending and receiving device 202 or the transceiver 200 with the interface 205. This interface 205 can be connected to a femto gateway which allows the femto access point 200 to receive data to be transmitted via the antenna 201 to a user equipment. The femto gateway is not shown in Fig. 2.

Interface 205 may be an Ethernet interface or a femto line interface. Thus, the femto access point 200 or the femto base station 200 may convert the air interface 201 to a line interface 205.

A HNB 200, femto access point 200 or femto base station 200 may differ from a macro base station, from a pico base station or from a micro base station in the capability to listen to another base station or scanning for another base station. A HNB may further be adapted for self-configuring. A HNB may not be subject of network planning. Therefore, by providing self-configuring functionalities a common untrained person may be able to install the HNB. For scanning the environment, the femto base station may switch for a predefined period of time in a UE mode, i.e. the base station may behave like a UE. Furthermore, a femto base station may be adapted to select the Tx power. A macro base station or a pico base station may use a substantially fix power value predefined by a network planning tool. A macro base station may not listen to another base station.

A femto access point may comprise a telephone switching function allowing a PBX operation (Private Branch exchange) or for providing a local breakout.

Connected to the sending and receiving device 202 is the cell detecting device 206. The cell detecting device 206 allows detecting the presence of a macro cell. The cell detecting device 206 may scan on a regular basis for the availability of a macro base station or a macro cell. The cell detecting device 206 is connected to the sending and receiving device 202 via link 207. The cell detecting device 206 has access to the reading device 209 via link 208. The reading device can read a data model or a data structure stored on the recording device 210. In particular, the reading device can read values from the data structure.

Not shown in Fig. 2 is a writing device, which may be adapted to write values to the data structure on the storing device 210, the recording device 210 or the recording carrier 210.

The recording device 210 has a data structure which the reading device 209 can read. Thus the reading device can access the correction parameters HNBTxPower values HIDDEN and MaxULTxPower HIDDEN if the cell detecting device 206 detects a hidden mode of the access point 200. The recording device 210 as shown in Fig. 2 is an internal device.

Alternatively to the internal recording device and/or in addition to the internal recording device 210 the reading device 209 via link 211 can access via the interface 205 to an external recording device which may be included in a femto gateway, which is not shown in Fig. 2.

Access to the recording device 210 may also be possible using an input/output device 213. This can be used to configure the data structure in the recording device 210.

Furthermore the femto access point 200 may also have a console interface for directly connecting an input/output device 213. Such a console interface is not shown in Fig. 2.

Power is supplied to the femto access point via the power supplying device 212. The power supplying device 212 may be a standard home power supply, for example based on 110 V or 230 V AC current. This may allow a femto access point to be installed in a home environment. A femto access point may be characterized in that the femto access point can scan for other base stations and/or can listen on a frequency of another base station.

Fig. 3 shows a block diagram of a controlling apparatus according to an exemplary embodiment of the present invention .

A controlling apparatus may be used for controlling a femto base station and/or for collecting and concentrating the traffic of a plurality of femto base stations connected to the controlling apparatus.

The controlling apparatus 300 comprises a reading device 301 for reading the recording device 302. Via the interface 303, which corresponds to the interface 205 of a femto access point, the recording device 302 can be accessed by a remote femto access point. Thus, the recording device 302 may be an external recording device. The recording device 302 comprises the data structure or the data model used by an femto access point. In other words, the recording device is structured by using the data model or the data structure.

The interface 303 in the direction to a femto base station may be Ethernet, IEEE 802.3, xDSL (ADSL, SDSL, VDSL) . An interface to the backbone of the controlling apparatus may be a STM-I (Synchronous Transport Module) .

Via the console interface 305 by input/output device 304 data can be configured on the recording device 302. The input/output device 304 may also be used to configure the recording device 210 on the access point 200. For configuring the femto access point 200 the input/output device 304 can be directly connected to the femto 200 or the input/output device ca be connected via the gateway 300 to the femto access point 200.

The recording device 302, 210 has a data structure comprising power correction values. These power correction values can be read by the reading device 301 and transmitted to an access point connected to the controlling device, for example a femto gateway, if the femto access point informs the controlling device 300 that no macro cell has been detected. Such information can be received by the gateway device via interface 303. This interface 303 may be an IP transport interface, an ATM (Asynchronous Transfer Mode) interface, an IP interface an Ethernet interface, an optical interface. The uplink interface of the controlling apparatus (not shown in Fig. 3) may be an ATM interface, a Gigabit Ehternet interface, an Ethernet interface or a STM interface.

Fig. 4 shows a flow diagram for a method for correcting at least one power value according to an exemplary embodiment of the present invention. The method starts in the idle mode S400. In step S401 the access point or the network apparatus detects a hidden cell mode of the network apparatus. In other words, in step S401 the network apparatus scans for a macro cell and detects that no macro cell is available.

In step S402 a power correction value, for example HNBTxPower values HIDDEN or MaxULTxPower HIDDEN is read if the hidden cell mode has been detected.

In step S403 at least one power value of the network apparatus is corrected based on the at least one power correction value. Correcting may comprise multiplying a group of parameters with a percentage value.

In step S404 an idle mode of the method may have been reached.

It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.

Acronyms and Terminology

FAP Femto Acces Point

OMS Operation and Maintenance System

HNB Home NodeB

Cpich Common Pilot Channel ADSL Asymmetric Digital Subscriber Line

SDSL Symmetric Digital Subscriber Line

VDSL Very High Speed Digital Subscriber Line

Claims

Patent claims

1. A network apparatus (200) for wireless communication, comprising: a cell detecting device (206); a reading device (209); wherein the cell detecting device (206) is adapted for detecting a hidden cell mode; wherein the reading device (209) is adapted for reading at least one power correction value if the cell detecting device

(206) has detected the hidden cell mode; wherein the cell detecting device (206) is further adapted for correcting at least one power value of the network apparatus based on the at least one power correction value.

2. The network apparatus (200) of claim 1, wherein the reading device (209) is adapted for reading the at least one power correction value from a predefined position in a data structure .

3. The network apparatus (200) of claim 2, wherein the data structure is stored on at least one storing device (210) selected from the group of storing devices (210) consisting of a record carrier, an internal record carrier, an external record carrier, a gateway apparatus, a femto gateway apparatus, a network storing device, a server, an operation and maintenance system, a computer-readable medium, and a database.

4. The network apparatus (200) of one of claims 1 to 3, wherein the at least one power value to be corrected by the at least one power correction value is a power value selected from the group of power values consisting of a MaxTxPower value, a P-CpichPowerConfig value, a P-CpichPowerAutoConfigEnable value, a P-CpichPowerlnUse value, a PrimaryCpichTxPower value, a UeTxPwrMaxRach value, a ConstantValue value, a MaxHNBTxPower value, and a MaxULTxPower value.

5. The network apparatus (200) of one of claims 1 to 4, wherein the at least one power correction value is at least one value of a HNBTx Power values HIDDEN value and a MaxULTxPower HIDDEN value.

6. The network apparatus (200) of one of claims 1 to 5, wherein the network apparatus (200) is at least one apparatus selected from the group of apparatuses consisting of a base station, a femto base station, a pico base station, a NodeB, and a Home NodeB.

7. The network apparatus (200) of one of claims 1 to 6, wherein correcting the at least one power value of the network apparatus (200) comprises multiplying the at least one power value with the at least one power correction value.

8. The network apparatus (200) of one of claims 1 to 7, wherein detecting the hidden cell mode comprises at least one condition of detecting a detection level below a threshold, an isolation of the network apparatus (200) from a macro cell and detecting a missing beacon.

9. A recording carrier (210, 302) having a data structure, wherein the data structure comprises at least one power correction value at a predefined position such that a reading device can access the correction value, if a hidden cell mode has been detected.

10. A controlling apparatus (300) for a network apparatus (200), the controlling apparatus (300) comprising: a reading device (301); wherein the reading device (301) is adapted for reading at least one power correction value on request of a network apparatus (300) .

11. The controlling apparatus (300) of claim 10, wherein the reading device (301) is adapted for reading the at least one power correction value from a predefined position in a data structure.

12. A method for correcting at least one power value of a network apparatus, the method comprising: detecting a hidden cell mode of the network apparatus; reading a power correction value if the hidden cell mode has been detected; correcting at least one power value of the network apparatus based on the at least one power correction value.

13. A program element, which when being executed by a processor is adapted to carry out: detecting a hidden cell mode of the network apparatus; reading a power correction value if the hidden cell mode has been detected; correcting at least one power value of the network apparatus based on the at least one power correction value.

14. A computer-readable medium comprising program code, which when being executed by a processor is adapted to carry out : detecting a hidden cell mode of the network apparatus; reading a power correction value if the hidden cell mode has been detected; correcting at least one power value of the network apparatus based on the at least one power correction value.