Method and device for transmitting data of a subscriber-specific control channel in a radio system

Abstract

The present invention aims at providing flexible and optimal configuration of an air interface of a transmitter in a radio system, more particularly a mobile radiotelephone system. According to the present invention, the data of a subscriber-specific control channel transmitted by the transmitter is transmitted with an adaptively modifiable frequency position or band width. The subscriber-specific control channel may include pilot symbols for channel evaluation, TCP symbols for power regulation, TFI symbols for transmitting transmission format information and other symbols, wherein the desired frequency position or band width can be individually adjusted for the individual symbol groups.

Description

[0001] The present invention relates to a method and a correspondingly configured device for transmitting data of a subscriber-specific control channel in a radio system. In particular the present invention relates to such a method and a correspondingly configured device for transmitting data of a subscriber-specific control channel, comprising different symbols with control functions, such as for example symbols for evaluating the transmission characteristic of the respective transmission channel, symbols for power regulation or symbols with details of format information, in a radio system, in particular a mobile radio system.

[0002] The functionality of a transmitter or receiver, such as for example a mobile station or a base station in a mobile radio system, is generally described in radio systems in the form of a layer model, wherein the various functionalities of the respective transmitter or receiver are assigned to different layers. In radio systems data of higher layers (layers 2, 3 or higher) is transmitted via the air interface (layer 1). It is characteristic of radio systems that the air interface of the respective transmitter or receiver represents the bottleneck in respect of data rate (kbit/s) and transmission capacity (bit/s/Hz). New radio systems therefore have to be designed and operated so that the air interface is configured as optimally as possible. Optimization criteria here can for example be the maximum data rate of one or more subscribers, the spectral capacity of an individual radio cell or the system as a whole, etc. Adaptive configurability of the air interface is desirable here, as optimum or optimized configuration of the air interface depends on many parameters, such as for example the environment or characteristic of the transmission channels, the nature of the radio cells, the nature of the multiple access method used (TDD (Time Division Duplex) or FDD (Frequency Division Duplex)), the current speed of the respective subscriber, the data rate, the system load and the nature of the data transmission (e.g. packet-based or continuous, etc.). The configuration of the air interface here is generally subscriber-specific (dedicated) and dependent on the parameters listed above.

[0003] In UMTS (Universal Mobile Telecommunication System) mobile radio systems a subscriber-specific control channel is used to configure the air interface of the respective receiver and is referred to as the Dedicated Physical Control Channel (DPCCH). Using this DPCCH channel, information is transmitted to the respective receiver, which said receiver can use to configure its air interface. In particular this DPCCH channel contains data blocks with Npilot pilot symbols for evaluating the transmission characteristic of the respective radio channel, NTPC TPC (Transmit Power Control) symbols with information for power regulation and NTFI TFI (Transmit Format Indicator) symbols with format information or for combining the services to be transmitted (voice, circuit-switched data, packet data, etc.).

[0004] Depending on the combination of the parameters listed above, different numbers of symbols are required for the individual data blocks of the DPCCH channel.

[0005] For transmission of the DPCCH channel in the FDD mode of UMTS mobile radio systems, a method is known for transmitting the DPCCH channel in the downlink, i.e. during transmission from a base station to a mobile station, comprising one data block each with pilot symbols, TPC symbols and TFI symbols according to a time multiplex method with the corresponding subscriber-specific data channel (dedicated physical data channel, DPDCH). In other words data of the DPDCH channel and data of the DPCCH channel are transmitted in succession in respect of time. In the uplink, i.e. during transmission from a mobile station to a base station, on the other hand, what is known as an I-Q multiplex combination of the DPCCH and DPDCH channels takes place.

[0006] With regard to transmission of the DPCCH channel it has already been proposed that the number of pilot symbols, TPC symbols and TFI symbols should be configured in a variable manner. In particular it has already been proposed that the values Npilot, NTPC, NTFI should be modified adaptively or optimized during an existing connection by a layer 2/3 signaling, which is transmitted via the DPDCH channel.

[0007] The object of the present invention now is to propose an alternative method and a correspondingly configured device for transmitting data of a subscriber-specific control channel in a radio system, such as for example the DPCCH channel in a UMTS mobile radio system, so that the greatest possible flexibility is achieved with the transmission of data of the subscriber-specific control channel, in order to be able to respond as quickly as possible depending on the combination of the parameters disclosed above, on which the configuration of the air interface in a transmitter or receiver of the radio system depends, and to be able to achieve a correspondingly optimized configuration of the air interface.

[0008] This object is achieved according to the invention by a method with the features of claim 1 and a device with the features of claim 17. The subclaims each define preferred and advantageous embodiments of the present invention.

[0009] According to the invention it is proposed that data of a subscriber-specific control channel be transmitted using an adaptively modifiable frequency position or bandwidth, i.e. the subscriber-specific control channel is implemented adaptively in the frequency range.

[0010] In mobile radio systems for example, such as those according to the UMTS mobile radio standard, the subscriber-specific control channel can be what is known as the DPCCH channel, which has both pilot symbols for channel evaluation as well as TPC symbols for power regulation and TFI symbols for format information. Each of these data blocks can be transmitted using an adaptive bandwidth or frequency position, i.e. it is possible during an existing connection to modify adaptively or optimize by means of a corresponding layer 2/3 signaling, which is preferably transmitted via the corresponding subscriber-specific data channel, such as for example the DPDCH channel in UMTS mobile radio systems.

[0011] The overall bandwidth made available to a subscriber may be either constant or variable.

[0012] Frequency spectra which do not necessarily have to be contiguous can be assigned to the individual data blocks. In this respect various embodiments of the present invention are presented which can be adjusted based on the operating conditions of the respective radio system, i.e. based on the current combination of the parameters disclosed above, by means of a corresponding layer 2/3 signaling.

[0013] The multiple access method preferred for fourth-generation mobile radio systems is what is known as the OFDM (Orthogonal Frequency Division Multiplexing) method. Here data blocks or data bursts are expanded cyclically and modulated in the frequency range. Using the OFDM method allows a transmission channel which exhibits relatively high levels of distortion with conventional transmission methods to be transformed into a channel without inter-symbol interference.

[0014] When using an OFDM method, both the data of the subscriber-specific data channel (DPDCH) and the data of the subscriber-specific control channel (DPCCH) is transmitted with a number of sub-carriers, also referred to as OFDM carriers or sinuids. The transmission proposed according to the invention of the subscriber-specific control channel with variable or adaptively modifiable bandwidth or frequency position can be implemented simply by varying the number and configuration of sub-carriers used in each instance for the individual data blocks correspondingly.

[0015] Different embodiments are also proposed for the transmission of data according to the OFDM method and these can be selected as required on the basis of the operating situation.

[0016] The present invention is described in more detail below with reference to the attached drawing using advantageous and preferred exemplary embodiments. In particular the present invention is described here on the assumption that the transmission of data of the subscriber-specific control channel and the subscriber-specific data channel takes place in a UMTS mobile radio system. Of course the present invention is not however restricted to this area of application but can in principle be used in any radio system in which a subscriber-specific control channel which contains specific control information for the receiver is transmitted from a transmitter to a receiver.

[0017] FIGS. 1A-1E show different exemplary embodiments of an inventive variation of the bandwidth or frequency position for the transmission of a DPCCH channel and a DPDCH channel,

[0018] FIGS. 2A and 2B show different exemplary embodiments of an inventive variation of the bandwidth or frequency position made available for the DPDCH channel and the DPCCH channel using an OFDM method, with the data being transmitted with a number of sub-carriers in each instance, and

[0019] FIG. 3 shows a simplified block diagram of a mobile radio system according to the invention.

[0020] According to the invention it is proposed that the transmission of the subscriber-specific control channel, i.e. the DPCCH channel (Dedicated Physical Control Channel), should be implemented adaptively in the frequency range so that data of the DPCCH channel is transmitted with an adaptively modifiable bandwidth or frequency position. The frequency position or bandwidth of the individual data blocks of the DPCCH channel can thereby be individually adjusted, i.e. the frequency position or bandwidth of the pilot symbols which are used for receiver-side channel evaluation, the frequency position or bandwidth of the TPC symbols which are used for receiver-side power regulation, the frequency position or bandwidth of the TFI symbols which are used for transmitting format information, and/or the frequency position or bandwidth of other symbols of the DPCCH channel can be adjusted individually, in order thereby to allow optimized configuration of the air interface. The bandwidth or frequency position of the pilot symbols is hereafter referred to as Bpilot, the bandwidth of the TPC symbols as BTPC, the bandwidth of the TFI symbols as BTFI and the bandwidth of the other symbols of the DPCCH channel as Bother.

[0021] During an existing connection the values for Bpilot, BTPC, BTFI and Bother can be adaptively modified or optimized by a corresponding layer 2/3 signaling which is transmitted via the corresponding subscriber-specific data channel (Dedicated Physical Data Channel) DPDCH. The overall bandwidth Btotal made available to a subscriber may be either constant or variable. The overall bandwidth Btotal made available to a subscriber is hereby defined as follows:

Btotal=BDPCCH+BDPDCH=Bpilot+BTPC+BTFI+Bother+BDPDCH.

[0022] Here BDPCCH designates the overall bandwidth for transmission of the symbols of the DPCCH channel and BDODCH the overall bandwidth for transmission of the symbols of the DPDCH channel. The frequency spectra of a subscriber allocated to Bpilot, BTPC, BTFI and Bother may also be non-contiguous, as can be seen from the description below of different exemplary embodiments with reference to FIG. 1 and FIG. 2.

[0023] First, however, the basic mode of operation of the present invention shall be described with reference to FIG. 3, with the assumption that the radio system is a mobile radio system with communication between a mobile station 1, which is in the form of a mobile telephone in the exemplary embodiment shown, and a base station 6. It is further assumed that the mobile station 1 is a device configured according to the invention which transmits a subscriber-specific control channel or DPDCH channel with an adaptively modifiable frequency position or bandwidth to the base station 6. Communication from the mobile station 1 to the base station 6 takes place via what is known as the uplink UL, while communication from the base station 6 to the mobile station 1 takes place via what is known as the downlink DL. The mobile station 1 receives information from the base station 6 via the downlink by means of a corresponding layer 2/3 signaling, which is transmitted via the DPDCH channel of the downlink DL, said information concerning how the bandwidth or frequency position of individual data of the DPCCH channel to be transmitted to the base station 6 should be adjusted. This information is fed via the air interface 2 of the mobile station 1 to the receiving part 3 of the mobile station 1 and analyzed by a control unit 4. Based on the analysis of this information the control unit 4 activates a transmission part 5 of the mobile station 1 in order to adjust the bandwidth or frequency position of the DPCCH channel or the individual data blocks of this DPCCH channel accordingly. The information which is received by the mobile station 1 from the base station 6 can be such that it selects a specific combination from a number of possible combinations of frequency positions or bandwidths of the individual data blocks of the DPCCH channel. The information can however also be such that it only determines the frequency position or bandwidth for an individual data block, for example only for the pilot symbols, of the DPCCH channel. As modification of the bandwidth of a data block generally also impacts on the bandwidth of the other data blocks, it is advantageous if a number of different combinations are stored in the mobile station 1 or the corresponding transmission part 5 for the bandwidths of the individual data blocks of the DPCCH channel and these then only have to be read and converted on the basis of the information received.

[0024] After adjusting the bandwidth of the DPCCH channel or the individual data blocks of the DPCCH signal, data of the DPCCH channel is transmitted via the air interface 2 to the base station 6.

[0025] FIG. 1 shows different exemplary embodiments for transmission of the DPCCH channel, with the bandwidth or frequency position made available to a subscriber for both the DPCCH channel and for the DPDCH channel being varied from FIG. 1A-FIG. 1E. As already described, this is signaled to the subscriber during a connection via a corresponding layer 2/3 signaling using a received DPDCH channel.

[0026] Data of the DPDCH channel is assigned the reference 7 in each instance here, the pilot symbols of the DPCCH channel the reference 8, the TPC symbols of the DPCCH channel the reference 9, the TFI symbols of the DPCCH channel the reference 10, and other symbols of the DPCCH channel the reference 11.

[0027] It can be assumed that the case shown in FIG. 1A shows the initial situation. Here two frequency bands are used for the DPDCH channel 7, while five frequency bands are used for the pilot symbols 8 of the DPCCH channel and one frequency band each for the TPC and TFI symbols of the DPCCH channel.

[0028] In the case shown in FIG. 1B, compared with FIG. 1A two of the five frequency bands of the pilot symbols 8 are allocated equally in each instance to the frequency bands for the TPC symbols 9 and the TFI symbols 10. The case shown in FIG. 1B is for example significant when the coherence bandwidth of the radio or transmission channel is significantly larger than in the case shown in FIG. 1A. The frequency bands used according to FIG. 1B then suffice for the pilot symbols 8 at the beginning and end of the overall frequency band. According to FIG. 1B an additional frequency band is also made available for the transmission of other data 11 of the DPCCH channel, so that the overall bandwidth made available to the subscriber is larger than in FIG. 1A.

[0029] In the case shown in FIG. 1C, compared with FIG. 1A further frequency bands are inserted for the pilot symbols 8. This is at the expense of the bandwidth for data 7 of the DPDCH channel. The case shown in FIG. 1C can in particular be used with radio channels with significantly smaller coherence bandwidth than in the cases shown in FIG. 1A and FIG. 1B.

[0030] According to FIG. 1D, compared with FIG. 1A a second frequency band is used for the transmission of the TPC symbols 9. This means that the TPC symbols can be transmitted with significantly greater reliability or significantly greater error protection than in FIG. 1A. Also in the case shown in FIG. 1D the additional frequency band used for the TPC symbols 9 is at the expense of data of the DPDCH channel 7, in particular at the expense of the first frequency band of the DPDCH channel.

[0031] In the case shown in FIG. 1E the frequency bands of the DPDCH channel 7 are increased compared with the case shown in FIG. 1A. The TPC symbols 9 are also transmitted with a larger bandwidth than in FIG. 1A. The bandwidth for transmission of the TFI symbols 10 is reduced compared with FIG. 1A, which may be useful, for example, in instances where only a small number of formats is permitted for the respective subscriber, so that a smaller bandwidth than in FIG. 1A is required for the reliable transmission of this format information. Generally according to FIG. 1E the overall bandwidth made available to the subscriber is larger than in the cases shown in FIGS. 1A-1D.

[0032] FIG. 2A and FIG. 2B show two different exemplary embodiments for transmission of data of the DPCCH channel and the DPDCH channel according to an OFDM multiple access method, with the data of both the DPDCH channel and the DPCCH channel being transmitted with a number of sub-carriers. The transmission of data with variable bandwidth or frequency position proposed in the context of the present invention can be implemented very easily with an OFDM multiple access method, as only the number and/or configuration of the sub-carriers has to be varied accordingly in each case for Bpilot, BTPC, BTFI, Bother and BDPDCH. In FIG. 2A and FIG. 2B each sub-carrier is shown in the form of a narrow block.

[0033] In the case shown in FIG. 2A five sub-carriers in total are used for the pilot symbols 8 of the DPCCH channel, said sub-carriers not being contiguous in respect of frequency but being distributed relatively evenly over the entire frequency band. Twenty sub-carriers in total are assigned to the DPDCH channel 7 and these are arranged in two frequency fields, each with eight sub-carriers and one frequency band with four sub-carriers. Also four sub-carriers are used in each case for the TPC symbols 9, the TFI symbols 10 and the other data 11 of the DPDCH channel and these are arranged on the basis of their frequency position, as shown in FIG. 2A.

[0034] FIG. 2B shows a variant of this exemplary embodiment, with four frequency fields or frequency groups in total being used, each with two sub-carriers, for the pilot symbols 8 of the DPCCH channel, said fields in turn being distributed relatively evenly over the entire frequency band. However only one sub-carrier is used in each instance for the TPC symbols 9, the TFI symbols 10 and the other data 11 of the DPCCH channel, the frequency position of said sub-carrier also being shown in FIG. 2B. Compared with the case shown in FIG. 2A, according to FIG. 2B significantly more sub-carriers are assigned to the DPDCH channel 7, with the DPDCH channel 7 comprising 48 sub-carriers in total, which are distributed over three non-contiguous frequency fields. The overall bandwidth made available to the subscriber, i.e. the total number of sub-carriers, is larger than in FIG. 2A.

Claims

1. Method for transmitting data of a subscriber-specific control channel in a radio system, wherein the data (8-11) of the subscriber-specific control channel is transmitted during an existing connection from a transmitter (1) to a receiver (6) of the radio system using a frequency position which is modified adaptively.

2. Method according to claim 1, characterized in that a subscriber-specific data channel (7) is also transmitted from the transmitter (1) to the receiver (6) in addition to the subscriber-specific control channel (8-11), wherein the overall bandwidth assigned to the transmitter (1) for transmission of the subscriber-specific control channel (8-11) and the subscriber-specific data channel (7) is modified adaptively.

3. Method according to claim 1, characterized in that a subscriber-specific data channel (7) is also transmitted from the transmitter (1) to the receiver (6) in addition to the subscriber-specific control channel (8-11), wherein the overall bandwidth assigned to the transmitter (1) for transmission of the subscriber-specific control channel (8-11) and the subscriber-specific data channel (7) remains constant.

4. Method according to one of the preceding Claims, characterized in that the subscriber-specific control channel comprises a first data group (8) with data for receiver-side channel evaluation, a second data group (9) with data for receiver-side power regulation, a third data group (10) with data for the transmission of transmission format information and/or a fourth data group (11) for the transmission of other information, wherein the first data group (8), the second data group (9), the third data group (10) and/or the fourth data group (11) are transmitted with an adaptively modified frequency position.

5. Method according to claim 4, characterized in that data of the first data group (8) for receiver-side channel evaluation is transmitted in a first frequency band, a second frequency band, a third frequency band, a fourth frequency band and a fifth frequency band, wherein information of a subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the first and the second frequency bands, wherein the second data group (9) with data for receiver-side power regulation is transmitted in a frequency range between the second frequency band and the third frequency band, wherein the third data group (10) with data for the transmission of transmission format information is transmitted in a frequency range between the third frequency band and the fourth frequency band, and wherein information of the subscriber-specific data channel (7) of the transmitter is transmitted in a frequency range between the fourth frequency band and the fifth frequency band.

6. Method according to claim 4, characterized in that data of the first data group (8) for receiver-side channel evaluation is transmitted in a first frequency band, a second frequency band and a third frequency band, wherein information of a subscriber-specific data channel (7) of the transmitter (1) and the second data group (9) with data for receiver-side power regulation are transmitted in a frequency range between the first frequency band and the second frequency band, and wherein the third data group (10) with data for the transmission of transmission format information and information of the subscriber-specific data channel (7) of the transmitter (1) are transmitted in a frequency range between the second frequency band and the third frequency band.

7. Method according to claim 4, characterized in that data of the first data group (8) for receiver-side channel evaluation is transmitted in a first frequency band, a second frequency band, a third frequency band, a fourth frequency band, a fifth frequency band, a sixth frequency band and a seventh frequency band, wherein information of a subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the first frequency band and the second frequency band, wherein information of the subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the second frequency band and the third frequency band, wherein the second data group (9) with data for receiver-side power regulation is transmitted in a frequency range between the third frequency band and the fourth frequency band, wherein the third data group (10) with data for the transmission of transmission format information is transmitted in a frequency range between the fourth frequency band and the fifth frequency band, wherein information of the subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the fifth frequency band and the sixth frequency band, and wherein information of the subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the sixth frequency band and the seventh frequency band.

8. Method according to claim 4, characterized in that data of the first data group (8) for receiver-side channel evaluation is transmitted in a first frequency band, a second frequency band, a third frequency band, a fourth frequency band and a fifth frequency band, wherein information of a subscriber-specific data channel (7) of the transmitter (1) and data of the second data group (9) are transmitted in a frequency range between the first frequency band and the second frequency band, wherein data of the second data group (9) is transmitted in a frequency range between the second frequency band and the third frequency band, wherein data of the third data group (10) is transmitted in a frequency range between the third frequency band and the fourth frequency band, and wherein information of the subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the fourth frequency band and the fifth frequency band.

9. Method according to claim 4, characterized in that data of the first data group (8) for receiver-side channel evaluation is transmitted in a first frequency band, a second frequency band, a third frequency band and a fourth frequency band, wherein information of a subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the first frequency band and the second frequency band, wherein the second data group (9) with data for receiver-side power regulation is transmitted in a frequency range between the second frequency band and the third frequency band, wherein the third data group (10) with data for the transmission of transmission format information and information of the subscriber-specific data channel (7) of the transmitter (1) are transmitted in a frequency range between the third frequency band and the fourth frequency band.

10. Method according to one of the preceding Claims, characterized in that data of the subscriber-specific control channel (8-11) is transmitted by the transmitter (1) to the receiver (6) with a number of sub-carriers, each of which is assigned to different frequency ranges, and wherein the number and/or configuration of the sub-carriers used for the data of the subscriber-specific control channel (8-11) is modified adaptively by the transmitter (1) in order to modify the frequency position of the data of the subscriber-specific control channel (8-11).

11. Method according to claim 10 and claim 4, characterized in that data of the first data group (8) for receiver-side channel evaluation is transmitted in a first frequency band, a second frequency band, a third frequency band, a fourth frequency band and a fifth frequency band, wherein information of a subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the first frequency band and the second frequency band, wherein information of the subscriber-specific data channel (7) is transmitted in a frequency range between the second frequency band and the third frequency band, wherein the second data group (9) with data for receiver-side power regulation and the third data group (10) with data for the transmission of transmission format information are transmitted in a frequency range between the third frequency band and the fourth frequency band, and wherein information of the subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the fourth frequency band and the fifth frequency band.

12. Method according to claim 11, characterized in that the first frequency band, the second frequency band, the third frequency band, the fourth frequency band and the fifth frequency band, which are assigned to the first data group (8), are each formed by a sub-carrier, twenty sub-carriers in total are assigned to the information of the subscriber-specific data channel (7), and four sub-carriers are assigned in each instance to the second data group (9) and the third data group (10).

13. Method according to claim 10 and claim 4, characterized in that data of the first data group (8) for receiver-side channel evaluation is transmitted in a first frequency band, a second frequency band, a third frequency band and a fourth frequency band, wherein information of a subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the first frequency band and the second frequency band, wherein the second data group (9) with data for receiver-side power regulation, the third data group (10) with data for the transmission of transmission format information and information of the subscriber-specific data channel (7) of the transmitter (1) are transmitted in a frequency range between the second frequency band and the third frequency band, and wherein information of the subscriber-specific data channel (7) of the transmitter (1) is transmitted in a frequency range between the third frequency band and the fourth frequency band.

14. Method according to claim 13, characterized in that the first frequency band, the second frequency band, the third frequency band and the fourth frequency band, which are assigned to the first data group (8), are each formed by two sub-carriers, 48 sub-carriers in total are assigned to the subscriber-specific data channel (7), and one sub-carrier is assigned in each instance to the second data group (9) and the third data group (10).

15. Method according to one of the preceding claims, characterized in that it is signaled to the transmitter (1) via a received transmission channel how the frequency position of data of the subscriber-specific control channel (8-11) is to be modified.

16. Method according to claim 15, characterized in that it is signaled to the transmitter (1) via a received subscriber-specific data channel (7) how the frequency position of data of the subscriber-specific control channel (8-11) is to be modified.

17. Device for transmitting data of a subscriber-specific control channel (8-11) in a radio system with controllable transmission means (5) for transmitting data of the subscriber-specific control channel (8-11) to a receiver (6), and with control means (4) in order to be able to activate the controllable transmission means (5) based on control information, so that data of the subscriber-specific control channel (8-11) is transmitted by the transmission means (5) during an existing connection with the receiver (6) with an adaptively modified frequency position based on the control information.

18. Device according to claim 17, characterized in that receiving means (3) are provided for receiving a transmission channel transmitted in the radio system and containing the control information for the adaptive modification of the frequency position of data of the subscriber-specific control channel (8-11).

19. Device according to claim 17 or 18, characterized in that the device (1) is a transmission device of a mobile radio system.

20. Device according to one of claims 17-19, characterized in that the device (1) is configured to perform the method according to one of claims 1-16.