Allocating speech items to mobile units communicating on a direct mode channel

FIELD OF THE INVENTION

The present invention relates to a method for allocating speaking permissions to mobile units communicating on a direct mode channel. The method comprises the steps:

Transmitting a transmission of a speech part by a first mobile unit during the speaking permission of the first mobile unit on the direct mode channel,

wherein a second mobile unit takes over the speaking permission,

Transmitting a transmission of a speech part by the second mobile unit during the speaking permission of the second mobile unit on the direct mode channel.

BACKGROUND OF THE INVENTION

The method according to the invention is in particular designed for use in Provide Mobile Radio or Professional Mobile Radio (PMR) networks, that is to say bundled networks, which are typically enterprise networks or government networks, all channels being shared by one or more user organizations. In such networks, subscribers have individual subscriber numbers and, in addition, group numbers indicating the communication group or subscriber group to which the subscriber belongs. Therefore, calls intended for subscribers of a particular group can be switched to the members of that group.

The invention is suitable for use in mobile communication systems with both digital and analog radio links. Analogous mobile communication systems are described, for example, in MPT 1327, A Signaling Standard for Trunked Private Land Mobile Radio Systems, January 1988, reprinted and reprinted in November 1991, and described in MPT 1343, Performance Specification, January 1988, revised and reprinted in September 1991 , both of which were published by the Department of Trade and Industry, Radiocommunications Agency, UK.

Group talk is one of the essential functions of a private mobile radio system. For example, a group conversation is used on all types of operations involving more than one participant, especially if an entire group is constantly from. Progress of events must be notified. A group discussion is a conference call in which all participants speak and hear each other in turn. For group calls, the entire group is called by a common number. A single radio unit, e.g. As a mobile unit or a radiotelephone, ie a subscriber station, may belong to several groups programmed in the radio unit. The programming may be fixed, but it may also be changed by the user of the mobile unit. Information about the base stations belonging to each group number is stored in the system. The group call may cover one, several or all base stations within the coverage area of ​​the mobile exchange or multiple mobile exchanges. When a group call is established, a traffic channel is assigned to all base stations belonging to the group, and each of these base stations transmits a group call message with the group number and information on the assigned traffic channel. If the mobile unit recognizes the group number contained in the group call message, it will switch to the traffic channel specified in the group call message. Therefore, in principle, the mobile unit is continuously available for a group call if it is within the predetermined operating range of the group and does not already participate in another group call.

In addition to system channels in mobile radio systems, direct mode channels can be used in the radio system, ie the operation takes place in direct mode. Subscriber stations communicating in direct mode do not communicate directly with the radio network or its base stations. Direct mode channels are frequency division multiplexed or time division multiplexed slots on which cellular telephones or other units outside the system can communicate directly with each other or through repeater stations either to the system base stations or to other mobile units.

Direct mode channels are typically used in situations where, for example, a number of handsets communicate with each other in a distance from the base station that does not allow use of the system channels.

Another important benefit of the direct mode channels is the capacity expansion when the traffic in the system in a part of the system service area, for example in a dot-shaped part, rises rapidly (for example, in an event).

A direct mode channel is called a simplex channel or simplex connection. A direct mode channel is a channel that is typically unavailable for system usage. For example, it may be a channel having a channel spacing corresponding to a mobile communication system, for example 12.5 kHz or 25 kHz. Of the radiotelephones communicating on a direct mode channel, the transmitter has tuned its transmitter to the channel and transmits voice or data information. The other radio telephones using direct mode channels have tuned their receivers to the same channel and will hear the transmission directly.

When operating on a direct mode channel, analog modulation or digital modulation can be used. A radiotelephone transmitting on a channel may also transmit signaling information, such as information about user rights and priorities, or information about the group communicating on the channel, or traffic. In a direct mode channel, encryption or clear speech can be performed.

In a typical group call traffic typical of PMR systems, it is necessary to provide a normal "free space" feature because usually two parties communicate and only want to listen to the others. In that case, it would be desirable for the two participants participating in the communication to be able to terminate their dialogue before a third party interferes with the communication with their speech part. In the known approaches, no solution to the above problem has been provided for the operation of the mobile units communicating on a direct mode channel.

WO 94/17642 A (Nokia Telecommunications Oy) relates to a method for allocating subscribers of the same group call group simultaneously requested voice over interfaces to a mobile exchange.

The solution disclosed in this reference comprises an entire mobile communication system having one or more mobile exchanges, associated base stations and mobile stations connected to the base stations.

The reference does not disclose a direct mode channel repeater or other repeater or parameters to be used in the repeater.

WO 95/24655 A (Nokia Telecommunications Oy) relates to a method for controlling a subscriber station operating on a direct mode channel in a radio system with a radio network having at least one base station and subscriber station, the radio system further comprising at least one repeater repeater station which controls the traffic between the at least one base station and the operated on the direct mode channel subscriber stations forwarded.

The reference discloses a mobile communication system having a base station, subscriber stations connected thereto, and a repeater repeater station which forwards traffic between the base station and the subscriber stations operating on a (separate) direct mode channel. The main idea of ​​this reference document is to manage one of the identifications of those subscriber stations, ie Mobile stations, storing database at the repeater station, which are operated on the direct mode channels within the supply area of ​​the Wiederholohlverstärkerstation.

WO-A-93 07723 (Nokia Telecommunications) discloses a method for realizing a group call in a digital radio network, wherein a plurality of mobile subscribers participating in the group call roam within the range of at least one base station. According to the method, the participants participating in the group call are successively guided to speak on the same radio channel. Thus, the traffic can be handled in a controlled manner at all times, without the radio channel is jammed by simultaneous speaking of participants, the base station is informed about the speech request of the subscriber after the subscriber has indicated his speech request by a predetermined signaling, the next speaker selected at the base station based on a predetermined algorithm, and the base station transmits an indication of speaking permission to the subscriber who is the next speaker at that time.

The problem of the known solutions is that there is no system for direct mode channels by which the beginning of the speech parts of mobile units participating in a group call is prioritized in such a way that, for example, two subscribers who have recently participated in the communication Possibility to terminate your dialogue before transferring the talk privilege to a third party.

BRIEF DESCRIPTION OF THE INVENTION

In the following description, the following terms are used: a last user is the user who spoke before the issuing user. A donating user is a user who issues his speaking permission, ie terminates his speech part.

It is an object of the present invention to solve the problems associated with the known solutions. Thus, the purpose of the invention is to realize an ultimate user priority in a group call in direct mode communication. This means that the last user is preferred in a group call on a direct mode channel.

This new method for assigning speaking permissions to mobile units communicating to a direct mode channel is achieved by the method according to the invention, characterized in that it further comprises the steps:

Instructing mobile units communicating on the direct mode channel to operate so as to give the first mobile unit a priority for starting the transmission of a voice part or requesting speaking permission after the termination of the talk part of the second mobile unit before the other mobile units communicating on the direct mode channel.

A second embodiment of the invention relates to a method for assigning speaking permissions to mobile units communicating on a direct mode channel, the method comprising the steps of:

Transmitting a transmission of a speech part by a first mobile unit during the speaking permission of the first mobile unit on the direct mode channel,

Taking over the speaking authorization by a second mobile unit,

Transmitting a transmission of a speech part by the second mobile unit during the speaking permission of the second mobile unit on the direct mode channel.

This method according to the second embodiment of the invention is characterized in that it further comprises the steps of:

Transmitting priority information from the second mobile unit on the direct mode channel indicating which mobile user (s) is prioritized to take the next speaking privilege on the direct mode channel,

Accepting the next speaking permission by the mobile unit designated as prioritized in response to the priority information,

Transmitting the transmission of the thus prioritized mobile unit during the next talk authorization.

The invention further relates to a mobile unit for communicating on a direct mode channel on which at least also a second mobile unit and other mobile units communicate, with a memory device, a transceiver and a control unit for controlling the operation of the mobile unit.

The mobile unit according to the invention is characterized in that it comprises a control device for controlling the mobile unit to operate in such a way that the mobile unit after the termination of a speech part of the second mobile unit priority to start the transmission of a speech part or to request a speaking permission in front of the other receives the mobile units communicating with the direct mode channel.

The invention is based on the idea of ​​last-user priority in such a way that such a speaker obtains a new speaking authorization faster than any other mobile unit communicating on the direct-mode channel. The object is that the speaker preceding the donating speaker immediately, after the termination of the speaking part of the originating speaker, obtains a speaking permission, if he so wishes, or that no other speaker / mobile unit receives a speaking permission from such last user.

The basis of the invention resides in the idea that the priority of the speaker preceding the originating speaker (to obtain the next speaker privilege) is increased so as to give him a speaking privilege more easily than the other. The last user priority can also be realized over several speech parts, so that the procedure favors not only the previous speaker but also the previous one.

The idea of ​​the invention is that the second mobile unit, which has taken over a speaking right after the speech part of the first mobile unit and ends this speech part, ie leaves their speaking authorization, adds to their transmission information about the fact that the speaker preceding the originating speaker That is, the first mobile unit is prioritized to obtain the next speaking privilege. In response to this information, the first mobile unit may take over the next voice privilege, if it so wishes, without being disturbed by the transmission of the talker portions of the other party's (third) mobile units on the direct mode channel. It will be appreciated that the ultimate user priority may be granted to either the immediately preceding, ie first, mobile or multiple last users.

An advantage of the method and the radio unit according to the invention lies in avoiding the problems with the known solutions, ie they allow a preference of the speaker preceding the emitting speaker in the allocation of the next speech part on a direct mode channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail below with reference to the accompanying drawings. Show it:

Fig. 1 is a schematic view of a situation in which participants participate in a group call on a direct mode channel.

2 shows a communication between radio units according to the invention on a direct mode channel,

3a and 3b are flowcharts of the operation of a mobile unit seeking a transmission authorization;

4a and 4b are flowcharts of the method according to the invention,

Fig. 5 is a block diagram of a mobile unit according to the invention which communicates on a direct mode channel.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 shows a schematic view of a situation in which participants participate in a group discussion. Subscribers S1, S2, S3 using their mobile units related to the present invention belong to the same group call G1; the other participants in this group discussion are not shown. The group call is conducted on a direct mode channel DM. The participants S1 and S2 take part in the group discussion by alternately speaking, so that a dialogue arises. According to the invention, the two speaking participants S1 and S2 have mutually speaking privileges in the first place in such a way that the conducted between these two participants dialogue can be terminated. The subscriber S3 desires to speak, but the speaking authorizations are assigned according to the invention only between the subscribers S1 and S2. Therefore, the subscriber S3 is denied the speaking permission until the dialogue between the participants S1 and S2 is completed and the previous speaker has finished his speech part. The arrow 10 in the figure indicates the exchange of speech parts between the subscribers S1 and S2, wherein the emitting subscriber S1 according to the invention inserts information into the transmission of its speech part that the speaker S2 precedent to the emitting speaker S1 for receiving the next speech part is prioritized. In response to this information, the previous speaker S2 may take over the next speech item, if he so desires, without being disturbed by the other (third) mobile units S3 wishing to speak on the direct mode channel by sending their speaking permission requests or speech parts.

2 shows a communication according to the invention between the radio units RU1, RU2, RU3 on a direct mode channel DM. The radio units may be mobile units or other elements equipped with a radio device that can communicate on a direct mode channel. The radio units may also be repeater stations of the mobile communication system. The invention operates in principle as described in connection with FIG. 1. The method of the invention can be realized, for example, in the following ways:

1. The mobile unit counter counts up in each case after a new talk part; this will be explained in connection with Fig. 3, and

Second Explicit addressing by which the originating speaker expressly indicates the party (s) intended for next speaker authorization on the direct mode channel; this will be explained in connection with FIG. 4.

FIGS. 3a and 3b show flowcharts of the method according to the invention. Here, a last-user priority counter integrated into the mobile units is used. By doing so, the mobile unit keeps a list of the number of speaking permissions taken after the speech permission of the mobile unit. This method operates in such a way that the mobile unit terminating its speech part adds to its transmission information about the number of last users preferred in the allocation of the next speech item.

In this embodiment of the invention, that is, the counter alternative, the procedure is such that a mobile unit, upon each delivery of a talk privilege, ie, terminating the speech and possibly releasing the PTT (push-to-talk) switch, sets its priority counter (see FIG. Fig. 5) to the initial value, z. B. 1, resets. The value of the counter is incremented whenever another mobile unit takes over speaking permission and begins to speak. The counter may also be incremented in response to a message informing the mobile unit that another mobile unit has issued its speaking privilege. Namely, at the termination of their speaking part, ie at the delivery of their speaking privilege, the mobile unit, in its transmission, informs the other mobile units of this fact. The mobile unit transmission may also include a command to other mobile units to take over a voice privilege such that the command gives priority only to those mobile units whose priority counter has a predetermined value, for example 1, or 2, especially the two previous speaker should be given the right to speak, ie they are to be preferred. Of course, this dispensing message may include any priority parameter value, depending on the desired type of preference of the last or previous mobile unit.

In the method, the mobile unit of the originating user indicates to the other mobile units the number of preferred last-users. Typically, only one last user / mobile unit is preferred. However, the method may also favor multiple previous mobile units. It is noted that the information about the number of preferred last-users included in the transmission of the originating speaker may also be a parameter specific to the direct-mode channel.

If an end-user wishes to speak after the termination of the speech part, this must be indicated to the mobile unit even before the termination of the speaking part of the donor speaker. An indication of this is the pressing of a PTT (push-to-talk) switch on the mobile unit whose user desires the next speaking privilege.

A mobile unit seeking a transmission authority stores information about the number of speaking permissions that have been accepted after the last transmission of its transmission as a voice part to the group call in question. If, in particular, this mobile unit has transmitted the previous voice part, the last user counter parameter of this mobile unit is equal to 1.

The transmission location is calculated from the use of the star location of the first random access frame and the last user counter of the mobile unit intended for transmission.

The mobile unit may begin transmission if no previous transmission locations were used. This determines the mobile unit by receiving a confirmation message from the originating mobile unit. If there is no confirmation of the originating mobile unit or if the acknowledgment is negative, the mobile unit starts to send a request for voice authorization in the usual way (first attempt).

The flowcharts shown in Figs. 3a and 3b show the operation 301 of a mobile unit RU seeking a transmission authorization. The mobile unit receives 302 a transmission on a direct mode channel. At the same time, the mobile unit RU monitors 303 whether the last user / subscriber's voice part is ended. If the voice part is not ended, the operation of the mobile unit returns to the previous step 302 where the mobile unit receives a transmission. On the other hand, if the speech part has ended, the mobile unit RU checks 305 whether its user has requested a speaking permission. If this is not the case 306, the mobile unit RU waits 307 for the user's speech part or for the beginning of the transmission. In the next step 310, a check is made as to whether the user has requested a talk permission, and if it has 315, the process flow proceeds to step 316, where it is checked whether the last user priority is claimed or activated. If, on the other hand, it was determined in step 310 that the user did not request speaking permission 311, it is checked in the next step 312 whether the communication starts. If not, execution of the method returns 313 to step 307, where the user's voice or the beginning of the communication is awaited. If, on the other hand, the communication starts, the last user counter is incremented by one level.

If the user has requested 315 a talk permission in step 310, the method proceeds to step 316 where it is checked whether the last user priority of the invention is claimed or activated. If not, the method proceeds to step 317, where the first starting location is set to the transmission location of the first requesting voice request plus the number of the last users. This first starting location can also be set higher than the aforementioned, ie higher than the send location of the first request for talk plus the number of last users. Thereafter, step 318 transfers the process to the normal first try procedure.

If, on the other hand, it is determined in step 316 that the inventive last user priority is claimed or activated 319, the method proceeds to step 320. In this step, it is examined whether the number of last users is greater than or equal to the value of the last user counter. If not, the flow of the process proceeds to step 317, from which the process continues to step 318 to the initial test procedure. On the other hand, if the number of final users in step 320 is higher 322 than the value of the last-user counter, the transmission location of the requesting voice request is set in step 323 to the transmission location of the first requesting voice request plus the value of the last-user counter. Thereafter, the next send location is waited in step 325. Thereafter, the transmission location of the requesting voice permission is examined in step 326. If the location is not correct 327, the method proceeds to step 324, where it is checked if the transmission begins. On the other hand, if the transmission location is not correct, a request for a talk authorization is sent in step 330 using the busy transmission location, and then it is checked in step 331 whether a positive acknowledgment has been received from the originating mobile unit RU. If this is not the case 332, the flow of the method proceeds to step 317, in which the start location of the first attempt is set. On the other hand, if the confirmation from the originating mobile unit RU is affirmative, the process proceeds to step 333 in which the mobile unit transmits its transmission. Thereafter, the process proceeds to step 334, where it is checked whether a speech part termination request arrives from the user. If there is no voice end request from the user before 335, the process returns to step 333 where the transmission is sent. On the other hand, if a voice end request is received from the user, the process proceeds from step 336 where the mobile unit issuing the talk permission sends priority information to the other mobile units communicating on the direct mode channel, informing the other mobile units that they can make an attempt to take over the speech privilege if their last user counter is 1. This value is used by way of example for the preference of the speaker who has owned the speaking right immediately before the delivering subscriber. Of course, the priority parameter may also be set to a different value, meaning that another end user or more than one end user is preferred.

Figures 4a and 4b show flowcharts of a method according to another embodiment of the invention in which explicit addressing is applied when a donor spokesperson allocates voice portions to those mobile units currently having the next speaker privilege.

In this embodiment, the procedure is arranged such that the mobile unit stores the identification of the last user (mobile unit) when the mobile unit receives from its user an indication that the user desires the next speaking privilege. When the user then terminates his speech part, the mobile unit sends in its transmission a request to the last user. In response to this request, the last user can take over the speaking privilege, if he so wishes.

In this method, the user terminating his speech part, that is the originating user, ie the mobile unit RU, uniquely indicates the address of the last user (s).

If the last user wants to speak after the speech part, this must be indicated to the mobile unit RU already before the termination of the speech part. In Fig. 4 this display is shown in step 408, in which it is checked whether the user has requested a speaking permission. For example, if the ultimate user wishes to speak, he can signal his request by pressing his PTT switch.

If the address of the mobile unit RU coincides with that indicated as the address of the previous mobile unit RU (last user) in the transmission of the speaking portion of the originating mobile unit RU, the mobile unit RU may make use of the possibility of requesting a speaking privilege reserved for the preceding mobile unit.

The transmission location is counted using the start location of the first random access frame.

If there is no acknowledgment from the originating mobile unit RU or if the acknowledgment is negative, the mobile unit RU starts the request for a talk authorization in the usual way in accordance with the first-attempt procedure explained above.

In the flowcharts of Figs. 4a and 4b, steps 401-415 correspond to steps 301-319 shown in Figs. 3a and 3b. The method proceeds to step 416 shown in Figs. 4a and 4b if it is determined in step 412 that the last user priority discussed above has been claimed or activated in the mobile unit speaking during the previous talk privilege. In such a case, it is checked in step 416 whether the address of the last user matches the mobile unit's own address. If this is not the case, the flow of the method proceeds 417 to step 413, which was explained as step 317 in the flowchart according to FIG. 3a. On the other hand, if the address of the last user coincides with the mobile unit's own address, the flow of the procedure advances to step 418 in which the mobile unit sends a request for speaking permission to the transmitting mobile unit transmitting the message indicating completion of transmission. In the next step, the mobile unit desiring to speak in step 419 monitors whether a positive acknowledgment of the speech permission request from the mobile unit requesting speech arrives from the originating mobile unit. If the confirmation is negative 420 or if no confirmation arrives, then the process proceeds to step 413 explained above, and from there to the first-time test procedure. On the other hand, if the confirmation of the originating mobile unit is positive, the flow of the method proceeds to step 421, in which the mobile unit stores the address of the previous (dispensing) speaker and starts the transmission, ie, takes over the speaking authorization. As long as the user of this mobile unit does not issue 423 a voice end request, ie, releases the PTT switch, the mobile unit transmits its transmission, ie retains its speaking authorization. When a voice end request arrives from the user of the mobile unit, ie, when the user releases the PTT switch, the mobile unit transmits 422 the priority information to the other mobile units communicating on the direct mode channel by adding the address of the last user to its transmission if the last user priority is claimed or is activated.

In operation in accordance with another embodiment of the invention, the procedure is such that the priority information is a talker identification information indicating the identifications of one or more previous talker parts whose talkers are prioritized to take over the next talk rendition. Here, the voice part identification information in the mobile units received the priority information is compared with the information stored in the mobile units about the identifications of the mobile parts used by the mobile unit. If the comparison shows that the mobile unit has been prioritized to take over the next call authorization and the mobile unit user has indicated its desire to take over the next call authorization, the mobile unit takes over the next call authorization as long as no other mobile unit indicated as prioritized has already reserved the next call authorization ,

Fig. 5 shows a block diagram of a mobile unit 500, ie a radiotelephone used by a subscriber, a mobile unit or a subscriber station, which communicates on a direct mode channel. The task of the transceiver (TX / RX) 501 is to tune to the particular radio channel used. The transceiver 501 includes an antenna 502 connected to a radio link RP. Normally, radio frequencies between 60 MHz and 1000 MHz are used (VHF and UHF range), although other frequencies can be used. On the radio link RP, an analog modulation can be used, usually a phase modulation is used as modulation. Other types of modulation can be used. For example, a voice frequency subcarrier (FFSK) may be used to transmit the signaling. Via the radio link can also be transmitted digitally. The mobile unit may be adapted to and communicate with the uplink and downlink frequencies of the direct mode channel.

A user interface 505 includes an electro-acoustic transducer device, typically an earphone 506 and a microphone 507, and, optionally, the initiation and termination of a call and buttons related to selection. Since the communication in a trunking system and in particular on a direct mode channel in a radio link RP is advantageously carried out in simplex mode, the handset usually also has a speech switch (PTT switch), which must be pressed during the speech part. The talk switch is not shown in FIG.

The task of a control unit 503 is to control the operation of the mobile unit. The control unit 503 has access to the user interface 505 from which it receives, for example, pulses for initiating and terminating a call. The control unit 503 can also deliver to the user, via the user interface 505, acoustic or optical signals related to the operation of the radiotelephone and / or mobile radio system.

The control unit 503 is connected to the transceiver TX / RX 501. The channel used by the transceiver is determined by the control unit 503, ie the transceiver 501 is tuned to the channel determined by the control unit 503, ie the radio frequency, and to a suitable time slot. The mobile unit according to the invention can be tuned to a direct mode channel and to the uplink and downlink channels (frequencies) of the system channels and also to a desired time slot of the channel. The transceiver 501 is also turned on under the control of the control unit 503. The control unit 503 receives and transmits signaling messages over the transceiver 501. A mobile unit 500 according to the invention which communicates on a direct mode channel can transmit, for example, in a radio system with a radio network having at least one base station and subscriber stations and optionally one or more repeater / gateway stations transmitting communication between at least one base station and subscriber stations communicating on the direct mode channel , be used.

The mobile unit communicating on a direct mode channel comprises a memory device 510, a transceiver 501, and a control unit 503 for controlling the operation of the mobile unit.

A mobile unit RU1, RU2 according to the invention; 500 (Fig. 5) comprises: a controller 516 for controlling the mobile unit RU1 to be operated so as to obtain the priority for starting a speech part or to have speaking permission after the termination of the talk part of a second mobile unit RU2 before the others requesting mobile units RU3 communicating with the direct mode channel.

The mobile unit according to the invention is characterized in that the control means 516 for controlling the operation of the mobile unit RU1 is adapted for giving priority to starting a speech part to the first mobile unit RU1 or requesting speaking permission immediately after the termination of the talk part of the second mobile unit RU2 within one predetermined period of time.

The mobile unit RU1; 500 (Fig. 5) according to the invention further comprises: an adder 517 for adding information to the transmission of the mobile unit RU1 when the mobile unit RU1 issues its previous speaking privilege. Wherein the information indicates that the mobile unit RU1 desires the priority to start a speech part or to request speaking permission immediately after the termination of the speech part of the second mobile unit RU2 acquiring the next speech permission.

The mobile unit according to the invention further comprises transmitter means 511 for transmitting priority information indicating which mobile unit (s) is (are) prioritized to request the next speaking authorization on the direct mode channel.

The mobile unit according to the invention further comprises a priority counter 512. The value indicated by the counter indicates the number of speaking authorizations taken over by other mobile units after the speech unit of the mobile unit.

In the mobile unit according to the invention, the transmitter means is arranged to insert the priority parameter value indicating the number of preferred last speakers into the priority information.

The mobile unit according to the invention further comprises comparator means 513 for comparing 320 the value of the priority parameter contained in the priority information received by the mobile unit with the value stored in the priority unit 512 of the mobile unit, the mobile unit being directed in response to the comparison for taking the next speaking authorization, when the comparison indicates the mobile unit is prioritized for the next speaking authorization, as long as no other mobile unit indicated as prioritized has already reserved the next speaking privilege.

Further, the transmitter device 511 in the mobile unit is configured to insert the identification of the mobile unit having the previous speaking privilege into the priority information, wherein the preceding mobile unit takes over the next speaking privilege in response thereto.

The mobile unit according to the invention further comprises a voice part initiating device 114 responsive to the first mobile unit identification included in the priority information transmitted by the second mobile unit RU2 for taking over the next speaking permission by the mobile unit.

The mobile unit according to the invention is further characterized in that the transmitter means 511 is turned off to receive voice-part identification information indicating the identification (s) of the previous voice part (s) whose speakers are prioritized to take the next speaking privilege into the priority information.

The mobile unit according to the invention further comprises comparator means 515 for comparing the talker identification information contained in the priority information received by the mobile unit with the information stored in the mobile unit about the identities of the mobile unit using the mobile unit, in response to the comparison for taking the next talk privilege if the comparison shows, that the mobile unit is prioritized to take over the next speaking authorization, as long as no other mobile unit indicated as prioritized has already reserved the next speaking privilege.

The drawings and this description in question serve only to illustrate the idea of ​​the invention. The method and mobile unit according to the invention for assigning speech parts to mobile units communicating on a direct mode channel may vary in their details within the scope of the claims. Although the invention has been described primarily in connection with PMR mobile units, the invention may also be used in conjunction with other cellular telephones or other mobile units or mobile telephones.