DE102004006762A1 - Data transmission method involves sending data packets from base station, using positive or negative acknowledgements with channel quality information in signals with negative acknowledgement from mobile station - Google Patents

Abstract

The method involves transmitting data over a channel in a communications network between a base station (BS) and a mobile station (MS) taking account of channel quality by sending data packets from base station to mobile station, sending a positive (ACK) or negative (NACK) acknowledgement with channel quality information in a signal from the mobile station, detecting the positive or negative acknowledgement by a first method, re-sending the packet if negative, detecting a positive or negative acknowledgement by a second method and evaluating the channel quality information sent with the negative acknowledgement : Independent claims are also included for the following: (A) an arrangement for a mobile station with a transmitter/receiver unit for data transmission and reception (B) a base station (C) and a communications network with a mobile station.

Description

The The invention relates to a method for data transmission over a data transmission channel in a communication network that connects between a sender and a receiver via a Radio link available is provided.

The capacity a data transfer from a sender to a receiver depends significantly assuming that up-to-date information regarding the transmission quality of the used Data transmission channels at Transmitters are available. Only then can the transmitter send parameters for the send data to the current situation to ensure satisfactory transmission results to achieve. As transmission parameters, for example, transmission power or modulation or coding scheme. The current information in terms of the transmission quality is off so-called "channel measurements" or "channel estimates" won.

The The problem will be explained below using an example from the UMTS standard described (UMTS: Universal Mobile Telecommunication System). For conceptual clarifications referenced to the description of the figures.

For UMTS was a high speed packet data transmission for one shared channel proposed, the so-called HSDPA (high-speed Downlink packet access). The receiver here is a mobile station, the transmitter is a base station. This HSDPA standard looks a slow one Signaling control information through higher layers of the OSI layer model (OSI: Open System Interconnection), which shows the channel measurements for HSDPA Taxes. As control information for these channel measurements are mainly the temporal rate of measurements, the time offset (shift) in terms of a reference and the number of repetitions in the transmission a measured value used. This means that after the construction a radio link or "Radiolink" at a fixed rate Measurements performed become independent of whether and when actually Data on the for HSDPA established common downlink data channel HSDSCH (Highspeed Downlink Shared Channel). Therefore, be on the one hand under certain circumstances many unnecessary Measurements performed, on the other hand can at the time of actual packet data transmission, the so-called "Packetcall" no current measurement available. A packet data transfer This can consist of several individual packet calls, each again can consist of several individual data packets.

The problem is as follows:
The CQI values or channel quality information messages, which are a measure of the downlink channel quality between the base station and the mobile station, are periodically determined by the mobile station and transmitted to the base station. This is necessary to allow the base station for the HS-DSCH to effectively select the modulation and coding scheme and the mobile station (s) to be operated. However, care must also be taken that the interference generated by the transmission of the channel quality information on the HS-DPCCH should be as low as possible. Therefore, methods for improving periodic channel quality information transmission are currently being investigated.

As a remedy has been proposed to take additional information about the state of the radio channel from the power control. However, this is not possible in the event that the mobile station is in the so-called soft handover mode or "soft handover" because of problems with the power control. By "soft handover" is meant a state in which a mobile station is connected to multiple base stations. The power is regulated so that the mobile station or the terminal can correctly receive the transmitted data with the aid of the received signals of all base stations. However, this does not generally mean that the mobile station correctly receives the signal of the particular base station transmitting the HSDPA data. Since the HSDPA data packets are only sent from this one base station to the mobile station, the power control optimized for a set of base stations does not provide satisfactory additional information. Therefore, the following suggestions have been made to solve the problem of current channel information data:
1. Activity-based channel quality information feedback (CQI: Channel Quality Information). In this case, the rate of the cyclic measurements is then increased as soon as it is determined at the terminal or at the mobile station that data is being sent. In the case of packet data transmission according to HSDPA, in particular with each feedback that a received packet could be decoded or not an additional channel information message CQI can be sent. This feedback can be for example a so-called "RCK" (acknowledgment) or "NAK"("noacknowledgment").

In other words, additional CQI measurement reports or channel quality information messages are used when the mobile station receives data on the HS-DSCH (eg, the mobile station may receive data on the HS-DSCH) transfer a CQI measurement report to the HS-DPCCH with each ACK or NACK).

Indeed be while an active data transfer through the increased Transmission rate for the channel information message may unnecessarily increase channel quality information messages sent, namely with each successfully transmitted data packet, where i.a. no objection to the change the transmission parameter or for transmission a channel information message exists, causing unnecessary interference in the upward direction is produced.

Second One more way consists of receiving an additional channel information message after receiving a NAK to send. So there will be extra Transmit CQI measurement reports or channel quality information, when the mobile station transmits a NACK on the HS-DPCCH Here there is the problem of detection of the NAK signal by the base station, to determine if a channel information message has been sent and thus has to be evaluated.

Third Furthermore, it is possible that extra CQI Transmit measurement reports when on the HS-SCCH on the physical layer one Requirement is made. Again, further channel quality information messages are transmitted, the lead to the disadvantages described above.

4th There is still the possibility that the detected channel quality already averaged in the mobile station, and only those averaged ones Transmit measurements as channel quality information become. Thereby have to Although less channel quality messages transmitted but the disadvantage is that no actual channel quality measurements are being transmitted can be but only those who have some time in the past which corresponds to the averaging time. Furthermore, also at These methods channel quality measurements not necessarily transmitted at the time when they are needed.

go out from this prior art, it is an object of the present invention a possibility for data transmission indicate at which the quality the transmission if possible low resource consumption is improved.

These The object is solved by the independent claims. advantageous Further developments are the subject of the dependent claims.

there is in a method for wireless data transmission between a mobile station, and a base station in a communication system a wireless Data transmission channel provided. The transmission over the Data transmission channel is packet-oriented or circuit-switched and discontinuous, so that always time-limited sections of data transmitted will be referred to as data packets in the following.

To Receipt of a data packet by the base station transmits the mobile station a positive acknowledgment or confirmation back if she has correctly received the data packet and a negative acknowledgment of receipt, if the data packet was not received correctly.

The Base station evaluates the receipt received by it, to determine if the receipt is positive or negative is.

By the transfer can the receipt but changed be corrupted, for example by noise, so that the base station the acknowledgment of receipt in certain circumstances erroneously determined.

• 1) wenn die Empfangsbestätigung positiv ist, führt die Basisstation die Datenübertragung fort.
• 2) wenn die Empfangsbestätigung negativ ist, a) sendet die Basisstation das Datenpaket, auf das sich die Empfangsbestätigung bezieht nochmals. b) Weiterhin wertet die Basisstation die mit einer negativen Empfangsbestätigung mitgeschickte Kanalqualitätsinformation aus. Optional passt die Basisstation für die weitere Übertragung Übertragungsparameter mittels der Kanalqualitätsinformation an.

Depending on whether the acknowledgment is recognized as positive or negative, the following actions are performed:

• 1) if the acknowledgment is positive, the base station continues the data transmission.
• 2) if the acknowledgment is negative, a) the base station transmits the data packet to which the acknowledgment relates again. b) Furthermore, the base station evaluates the channel quality information sent with a negative acknowledgment. Optionally, the base station adjusts transmission parameters by means of the channel quality information for further transmission.

A Channel quality information is sent by the mobile station only if this is a negative acknowledgment of receipt sends. This ensures that on the one hand a current channel quality information is present at the base station, if this is not due to correct reception of data packets one or more transmission parameters adapts. On the other hand, no channel quality information is sent unnecessarily, if no adjustment is required in the case of a positive acknowledgment is.

It Now core of the invention is that the determination of whether the acknowledgment is positive or is negative for the actions a and b are different, so with a first Investigation method and a second investigation method.

This has the advantage, one investigation each method, which takes into account the consequences of a misjudgment of the acknowledgment of receipt for the respective action.

The Determination method can be chosen in particular so that for the action a) the likelihood that a negative acknowledgment of receipt will be erroneous is determined to be positive compared to the reverse error, namely that a positive acknowledgment as falsely is determined negatively, much lower fails.

This has the advantage of definitely serious transmission errors avoided because the base station in the case of a positive confirmation the faulty package is not repeated, but with the next package continues. Only higher layers a transmission protocol for the respective transmission note that this package is missing and it therefore needs a data packet retry from the higher ones Layers performed become. In contrast, it is less bad if a positive one confirmation falsely as a negative confirmation is interpreted.

Consequently can be - with resource-saving transmission of channel quality information - the quality of the transmission across from improve the state of the art.

Especially It can be provided that the evaluation of the channel quality information under b) only if, by means of the second investigation method a negative acknowledgment was detected or detected.

Especially it is also envisaged that, so that the sender adapted the data to the current channel quality of the communication channel can, from the receiver repeatedly transmit channel quality information to the transmitter becomes.

According to one advantageous embodiment, it may be in the communication network to act a mobile network in particular according to the UMTS standard. The transmitter can be a fixed base station and the receiver to trade a mobile station. In particular, such a data transmission method can be used apply to HSDPA.

As well the mobile station can represent the transmitter and the base station the recipient. This data transmission method let yourself then, in particular, a high speed uplink transmission from the mobile station to the base station, for example HSUPA (High Speed Uplink Packet Access) or EUDCH (Enhanced Uplink Dedicated CHannel).

One wireless data transmission channel can by a radio link or an optical transmission be formed.

The The invention further relates to a mobile station and a base station and a communications network by which this method is performed.

The Invention will be explained below by way of examples, which partly also shown in the figures:

1 shows the schematic relationship between transmitter, receiver and network;

2 shows the principle of a NACK based transmission method;

3 shows the timing of signaling in HSDPA.

Before a detailed presentation of the figures, the terms used should be clarified:
A communication system or communication network is a structure for exchanging data. This may be, for example, a cellular mobile radio network, such as the GSM (Global System of Mobile Communications) network or the UMTS (Universal Mobile Telecommunications System) network. A communication network comprises at least two connection nodes, so there are also so-called "point to point" connections under this term.

In A communication system is generally mobile stations and base stations provided via a radio interface communicate with each other. In UMTS assigns the communication system or radio transmission network at least base stations, here also called NodeB, as well as radio network Controllers or Radio Network Controller (RNC) to connect of the individual base stations. The terrestrial radio access network or "Universal Terrestrial Radio Access Network "UTRAN is the radio technical part of a UMTS network in which, for example also the radio interface is provided. A radio interface is always standardized and defines the totality of the physical and protocol requirements for data exchange, for example the modulation method, the bandwidth, the frequency deviation, access method, Backup procedures or mediation techniques. The UTRAN So at least includes base stations and at least one RNC.

A Base station is a central unit in a communication network, in the case of a cellular Mobile network terminals or mobile stations or communication terminals within a Mobile network cell one or more radio channels served. The base station puts the air interface in between Base station and terminal ready. She takes over the handling of the Radio operation with the mobile subscribers and monitors the physical Radio link. About that It also transmits the Payload and status messages to the terminals. The base station has no switching function, but only a supply function. A Base station comprises at least one transmitting / receiving unit.

One Terminal can be any communication terminal over which a user communicates in a communication system. It's falling For example, mobile devices like mobile phones or portable computers with a wireless module underneath. A terminal is often referred to as a "mobile station" (MS) or in UMTS "user equipment" (UE).

in the Mobile radio is differentiated between two connection directions. The downlink or "downlink" (DL) the transmission direction from the base station to the terminal. The Uplink (UL) denotes the opposite direction of transmission from the terminal to the base station.

In Wideband transmission systems, such as a UMTS mobile network, a channel is a subset one available standing total transmission capacity. As a radio channel becomes in the context of this application a wireless communication way designated.

In A mobile radio system, for example UMTS, is available for transmission Data Two types of physical channels: Dedicated Channels and Shared or "Common Channels". At the Dedicated Channels becomes a physical resource only for the transmission of information for a reserved specific terminal. The common channels can transmit information be that for all terminals are thought, for example, the primary common physical control channel or "Primary Common Control Physical Channel" (P-CCPCH) in the downlink, or all terminals share a physical resource. This is the case with HS-PDSCH, which is connected to a terminal in dependence from the connection quality data is sent to the terminal.

In Mobile radio systems such as UMTS are in addition to circuit-switched or "circuit switched" services in which a connection during their duration is fixed, also packet-oriented or "packet switched" services provided. Circuit-switched Services can also carried out batchwise become. For packet-oriented services, it is envisaged that the receiver the data packet sends an acknowledgment to the sender as to whether he has the data packet received correctly or not. A positive affirmation for one correct reception is called ACK or "Acknowledge", a negative acknowledgment as NACK or "Not Acknowledge".

In 1 a transmitter S and a receiver R can be seen in a communication system CN. The transmitter S transmits data to the receiver R via a first channel connection CH1. The receiver R may send data to the transmitter S via a second channel connection CH2.

Of the Sender S may for example be a base station, the receiver R a Terminal. The communication network system may be, for example to a system according to the UMTS, GSM or other standards. The first channel connection CH1 can have multiple channels include, for example, a data transmission channel for transmission of user data or "load bits "and one Control channel for transmission of control information. The second channel connection CH2 can only one Control channel include or as the first channel connection CH1 consist of a control channel and a data transmission channel.

For a transfer of payload data over the Data transmission channel the first channel connection CH1 from the transmitter to the receiver it is important that the channel quality this data transmission channel is known. For this purpose, the receiver determines, so for example the Terminal, channel quality information from first channel connection data or "channel quality information "CQI.

Of the receiver R can this channel quality information also from data from general control channels. In case of HSDPA would this is, for example, the general pilot channel CPICH (Common Pilot Channel).

These Channel quality information or "Channel Quality Information "CQI is from the receiver R transmitted to the transmitter S, for example via the control channel the second channel connection CH2.

Now, it is important for the data transmission over the first channel connection that the most timely channel quality information CQI is available at the transmitter S. At the same time, channel quality information CQI should not be sent unnecessarily since, as already mentioned, this leads to interference. That's why in the context of the invention, a timing of the transmission of this channel quality information CQI proposed.

2 shows the principle of NACK based transmission. For this purpose, a period T is plotted for a channel quality information feedback cycle in which cyclic channel quality information messages R-CQI are repeatedly transmitted. After receiving data D from the base station BS, the mobile station MS sends back an acknowledgment (ACK / NACK). Together with a negative acknowledgment NACK, a channel quality information message CQI or CQI measurement report is additionally transmitted.

The Mobile station transmits with every NACK in addition a CQI measurement report on the HS-DPCCH within a transmission interval of 2 ms to the base station. A transmission interval on the HS-DPCCH consists of 3 UMTS time slots. The first time slot consists of 10 bits and contains the ACK / NACK information. The second and third timeslot comprises 20 bits and contains the CQI measurement information of the mobile station. Will on the first time slot to transmit an ACK so the ACK message consists of ten ones and in the case of a NACK from ten zeros. The so binary represented ACK / NACK Information becomes transmission on the physical channel (I or Q) nor with a specific one Channel code and the for the mobile station specific "scrambling Code "scrambled Binary values "1" are mapped to -1 and "0" to "+1".

to Detection at the base station uses a threshold decision. The receive signal of the RCK / NACK time slot is descrambled and undone the modulation with the channel code. The so decoded ten bits or their representation (+ 1 / -1 Mapping) are accumulated. about a threshold decision is then made as to whether the sent Information was ACK or NACK. When looking for the transition probabilities P (ACK → NACK) = P (NACK → ACK) you choose the threshold S of the decision to S = 0. Is the accumulated Sum A is therefore greater than S = 0 then one decides for NACK, otherwise for ACK.

Now occurs, however, when a NACK is mistakenly interpreted as ACK will, a serious protocol error occurs because the base station in this case, the faulty package is not repeated, but With the next Package continues. Only the higher ones Layers determine that this package is missing and it must therefore a packet repetition from the higher ones Layers performed become. In contrast, it is less bad when an ACK is mistaken is interpreted as NACK. Therefore one strives for the error probabilities that P (NACK → ACK) ≈ 10e-4 <P (ACK → NACK) 10e-2.

This can be achieved in the detection by the above described Detection algorithm does not set the threshold to zero but S <0 selects, so that the above transition probabilities are fulfilled.

Depending on the above-described ACK / NACK decision, i. exactly in case The NACK decision now evaluates the base station's CQI information out.

there If you mistakenly find an ACK as an issue, then there is a problem NACK detected: Then noise is evaluated as CQI (since no CQI has been sent) and this will be more likely Value for the channel transmission quality assumed, which is faulty, which in turn reduces the efficiency of subsequent transfers and thus degrades throughput. To avoid that for the CQI Evaluation, if wrongly an ACK is detected as NACK, noise is evaluated as CQI, In the context of the notification, improvements are proposed: im Contrary to the transmission protocol as described above, the error NACK is detected as ACK is more serious than ACK is detected as NACK, is for the evaluation of the NACK based CQI the error ACK is detected as NACK severe.

Around this must be compensated for the ACK / NACK evaluation to which the following CQI detection connects, the threshold can be set differently than for the general ACK / NACK evaluation. Since the error ACK → NACK a stronger one negative impact on the performance of NACK based CQIs has NACK → ACK as the error you choose P (NACK → ACK)> P (ACK → NACK). The is equivalent to a threshold S> 0.

Around the CQI evaluation described above, based on the ACK / NACK evaluation is based (in time slot or "slot" 1 of the HS-DPCCH NACK detected so in Slot 2 and 3 the presence of a CQI codeword is assumed) To further improve, you can also have a DTX evaluation for the CQI perform as described below (DTX is an abbreviation for "Discontinuous Transmission ", that means "exposed Send ", DTX evaluation means that the base station estimates whether the mobile station at all has sent a CQI codeword).

If an NRCK is detected in slot 1, as described above, it is additionally evaluated whether the signals detected in slot 1 and slot 2/3 or in slot 2/3 are detected te signal energy is above a certain threshold. Only then will you decode the CQI value and apply it to the base station.

Of the Basic idea of the invention, namely the consideration but both the ACK / NACK and the CQI can also be for further improvement applied: Is an ACK in slot 1, as described above detected and can due to the periodic CQI measurement in this transmission interval no periodic CQI occur, so you evaluate in addition, whether the signal energy sent in slot 2/3 (or part of slot 2/3) below a certain threshold. Only then does one turn the ACK Decision. Otherwise, you revise the decision to a NACK Decision. The background is that after a NRCK a CQI sent should be. But if now after a supposed ACK in Slot2 / 3, so in the for the CQI reserved slot, a signal is detected, although there there should be no signal, this indicates that the detection of the ACK was wrong. As described above, a fake Detection of an ACK instead of a NACK has serious consequences for the protocol it is especially beneficial if the probability for such an error can be reduced even further.

general can you say that for The decision as to whether an ACK or NACK was received was not only the while of the slot 1 received signals, but also in the slot 2/3 (or a part from slot 2/3) received signals are evaluated.

adversely In the described method is that the decision based later on the CQI can be taken as the decision based on the RCK / NACK, since the former is in Slot 2 and 3, the latter is already sent in Slot 1. Depending on the implementation of the following steps, and depending on when these next steps at the latest have to be started In certain implementations, it may not be possible anymore perform all actions which could follow the detection of the NACK. For example, it can be that no longer possible is the repetition of the original requested by the NACK Data packages at the earliest possible date but you can still do this repetition to one later Send time, but i.A. will be much earlier than the repetition, that would arise if higher Protocol layers would correct this error. It also turns out in such a case, a performance improvement.

Other Actions that may not be done on time e.g. the selection of the user (s) to be served (e.g. Algorithms that prefer repetitions, this preference may not be available for the discussed user, but possibly only at the next Selection in the next Frame).

in the The following are selected Examples that apply to HSDPA are explained in more detail. The invention is however also, for example, in a corresponding high-speed transmission method in the upward direction use, for example, a method according to HSUPA or EUDCH.

In 3 is the timing of signaling in HSDPA seen. In the downlink direction control information is sent on the so-called common high-speed control channel HS-SCCH or "High-Speed Shared Control Channel". Two timeslots later, transmission of the actual data on the associated communication channel, the high-speed physical downlink physical channel HS-PDSCH, begins. An arrow indicates when the corresponding acknowledgment AN (Ack / Nack) about correct decoding (ACK) or the incorrect decoding (NAK) from the terminal in upward direction to the base station is indicated. This confirmation or feedback AN is marked in the drawing with a running index n and hatching. The period of measurement of the data for the channel quality information CQI is referred to as the measurement period MP.

Of the second arrow from the feedback AN, n in the HS-DPCCH to the HS-SCCH indicates at what time this confirmation at the transmitter, so the base station is present again and thus a appropriate response to the HS-SCCH can take place. The times, from where a reaction is possible is at HS-PDSCH and HS-SCCH grayed out.

• 1. Vom Kommunikationsnetz vorbestimmte, insbesondere zyklisch wiederkehrende CQI-Feedbacks. Die Vorbestimmung kann insbesondere durch eine zentrale Einheit wie Basisstation oder RNC erfolgen. Eine Vorbestimmung durch die Basisstation hat den Vorteil, dass sich der Funkverkehr insbesondere in Hinblick auf Interferenzen innerhalb einer Funkzelle einfach regeln lässt bei einer Regelung mit dem RNC kann auch eine Regelung in Hinblick auf mehrere Funkzellen erfolgen.
• 2. Zusätzliche CQI-Feedbacks bei Senden eines NAK von dem Mobilteil an die Basisstation

In this embodiment, two different occasions for a transmission of channel quality information or "CQI feedback" are now used:

• 1. From the communication network predetermined, in particular cyclically recurring CQI feedbacks. The predetermination can be carried out in particular by a central unit such as base station or RNC. A predetermination by the base station has the advantage that the radio traffic can be easily controlled, in particular with regard to interferences within a radio cell. In the case of a control with the RNC, it is also possible to regulate with regard to a plurality of radio cells gene.
• 2. Additional CQI feedback when sending a NAK from the handset to the base station

The The invention was based on the example of a threshold-based detection or determination method for the evaluation of the received acknowledgment is described. Instead, you too can Other methods of investigation are used, including these algorithms are designed so that in each case the probability of a momentous Detection or Detection error is reduced.

S:

transmitter

R:

receiver

CN:

communication network

CH1:

First channel connection

CH2:

Second channel connection

DTX1:

First data transfer

DTX2:

Second data transfer

DTX3:

third data transfer

CQI-TX:

Regular transmission of channel quality information

TS:

time slot

MP:

measurement period

TB:

transport block

AT:

feedback

Claims (12)

Method for data transmission via a data transmission channel (CH2) in a communication network (CN) operating between a base station (S) and a mobile station (R) for wireless transmission and in which the data transfer considering the channel quality takes place, with the following steps: - Transmission of data packets from the base station (S) to the mobile station (R); - Send a positive confirmation the correct reception (ACK) or a negative acknowledgment of the non-correct receipt (NACK) of the data packet with channel quality information by means of a signal from the mobile station and the base station; - Determine from the signal received from the base station using it a first determination method, whether a positive acknowledgment (ACK) or a negative confirmation (NACK) is present; - In the Case that determines a negative confirmation with the first investigation method becomes: - retransmission the data packet from the base station to the mobile station; - again Determine based on the signal received from the base station at Using a second discovery method, whether a positive acknowledgment (ACK) or a negative confirmation (NACK) is present; - Evaluation the one with the negative confirmation (NACK) sent channel quality information through the base station. The method of claim 1, wherein for the first Investigation method a first probability, a positive affirmation as negative confirmation to determine is less than a second probability, one negative confirmation to detect as a positive. Method according to Claim 1 or 2, in which the signal a first signal portion containing the confirmation and a second signal portion, the the channel quality information contains wherein in the base station first the first component is evaluated. The method of claim 3, wherein, after having first determination method determines a positive confirmation as a result was evaluated, the second signal component and based on the Evaluation of the result regarding the confirmation maintained or revised. Method according to one of the preceding claims, in for first or second determination method transmitted with the signal binary information is accumulated and where a threshold is defined above or below which there is a positive confirmation. The method of claim 5, wherein the first and second Using either a first or second threshold, being for the first and the second threshold, however, an equal amount a different sign can be selected. Method according to one of the preceding claims, in the determination is carried out by means of the first method of investigation, that with higher Probability of a negative acknowledgment (NACK) is detected, if indeed no signal was sent and in which the determination by means of the second investigation method is carried out in a way that is more likely a positive confirmation (ACK) is detected, if indeed no signal was sent. Method according to one of the preceding claims, in the channel quality information about at least a measurement, in particular immediately before a transmission of channel quality information in the mobile station is detected. Method according to one of the preceding claims, in which the communication network is a mobile radio network, which according to the UMTS standard and the data transfer procedure is HSDPA. Mobile station with a transmitting / receiving unit for transmitting and receiving data about one Radio link and a processor unit, which for carrying out a Method according to one of the preceding claims 1 to 9 is set up. Base station with a transmitting / receiving unit for transmitting and receiving data about one Radio link, with a connection to a communication network and a processor unit, which for carrying out a method according to a of the preceding claims 1 to 9 is set up. Communication network with a mobile station according to claim 10 and a base station according to claim 10.