Method, Terminal and radiocommunications system for transmission of group messages

0001It is an object of the invention to show a way in which at least one group can be notified as efficiently as possible of at least one group message from one or more subscriber devices of a radio communication system. This object is achieved by the following method according to the invention:

0002Method for notifying at least one group of one or more subscriber devices of a radio communication system that at least one group message is to be sent to this group by at least one network element of the radio communication system via at least one radio channel, the presence of this group message using the subscriber devices of the respective group of a common additional group paging indicator signal is displayed and provided for evaluation.

0003As a result, it is effectively possible to announce to the one or more subscriber devices of a predefinable group together with the aid of the additional group paging indicator signal that at least one group message from at least one network element of the radio communication system is pending for transmission over at least one radio channel for this group. On the basis of the group paging indicator signal, the respective subscriber device can make a preselection as to whether it additionally listens to at least one further radio channel with further information about the group message to be transmitted. If the respective subscriber device is not affected by the pending group message, it is therefore not necessary for it to actually set up a signaling connection via at least one radio channel to at least one network element of the radio communication system. This enables radio resource and energy-saving operation of the respective subscriber device. Because only if the respective subscriber device belongs to the respective addressed group does it listen to at least one further radio channel in order to listen to further information about the pending group message to be transmitted.

0004The invention further relates to a subscriber device of a radio communication system which is designed such that it can be operated using the method according to the invention.

0005The invention also relates to a radio communication system for carrying out the method according to the invention.

0006Other developments of the invention are given in the subclaims.

0007The invention and its developments are explained in more detail below with reference to drawings.

0008Show it:<dl id="dl0001"><dt>Figure 1</dt><dd>a schematic representation of components of a radio communication system for the notification according to the invention of at least one group of one or more subscriber devices,</dd><dt>Figure 2</dt><dd>a schematic representation of a layer model of the protocols on the air interface between a subscriber device and the responsible base station in the radio cell of this subscriber device in the radio communication system according to FIG. 1, in particular according to the UMTS standard,</dd><dt>Figure 3</dt><dd>1 shows a schematic representation of the structure of the frame structure of the separate, physical radio channel for transmitting a group paging indicator signal for the notification method according to the invention in the radio communication system according to FIG. 1,</dd><dt>Figure 4</dt><dd>1 shows, in a schematic illustration, an advantageous signaling sequence for notifying a group of subscriber devices of the radio communication system according to FIG. 1, starting from at least one network component, in particular a base station, about the presence of at least one group message to be transmitted on the network side,</dd><dt>Figure 5</dt><dd>In a schematic representation, information elements of the system information, which is transmitted between at least one base station of the radio communication system according to FIG. 1 and at least one subscriber device in its radio cell, this system information being expanded by an additional information element which is used to mark whether the so-called secondary common control physical Channel in UMTS a paging channel with information about the group message is multiplexed,</dd><dt>Figure 6</dt><dd>in a schematic representation the information element "PICH-Info" as a further part of the system information according to FIG. 5, with the position of a possible group paging indicator signal in the frame structure of its radio channel according to FIG. 3 for each subscriber device in each of the pending group message by means of an additional information element affected radio cell of the radio communication system is additionally transmitted,</dd><dt>Figure 7, 8, 9</dt><dd>additional information elements according to a first variant of the method according to the invention on the type and reason of the present group message to be transmitted, which are transmitted on a separate radio channel, in particular a paging channel, and</dd><dt>Figure 10, 11</dt><dd>Modified information elements of the so-called paging channel or channel in UMTS, which contain further information about the type, the reason and / or the specific group for which the pending group message is intended.</dd></dl>

0009Elements with the same function and mode of operation are provided in FIGS . 1 with 11 with the same reference numerals .

0010Elements with the same function and mode of operation are provided with the same reference numerals in FIGS. 1 with 10.

0011FIG. 1 shows a schematic illustration of two radio cells CE1, CE2 of a radio communication system FCS, which is operated in particular according to the UMTS (Universal Mobile Telecommunication System) standard. The radio cell CE1 is spanned by the base station BS1 in terms of radio technology, while the second radio cell CE2 is supplied from the base station BS2. The two base stations BS1, BS2 are representative of a large number of further base stations, not shown in FIG. 1, of the radio communication system MCS which have and cover corresponding radio cells. The respective base station is preferably formed by at least one radio transmitter and at least one radio receiver. It preferably has at least one transmitting antenna. In addition to or independently of their function of providing a radio connection to subscriber devices of the radio communication system FCS, the respective base station can in each case take care of the data / message transmission to any existing fixed message / data network.

0012In the radio communication system FCS, message / data signals are transmitted via at least one predefined air interface between at least one subscriber device, in particular a mobile radio device such as a cell phone, and at least one base station, preferably using a time-division multiple access transmission method. It is preferably designed as a mobile radio system according to the UMTS standard (= Universal Mobile Telecommunication System). In particular, it is operated in the so-called FDD mode (Frequency Division Duplex). In FDD mode, separate signal transmission in the up and down link direction (up link = signal transmission from the mobile radio device to the respective base station; down link = signal transmission from the respectively assigned base station to the mobile radio device) by means of a corresponding separate assignment of frequencies or Frequency ranges reached. Several subscribers in the same radio cell are preferably separated using orthogonal codes, in particular using the so-called CDMA method (= Code Division Multiple Access).

0013Mobile radio telephones, in particular cell phones, are preferably provided as subscriber devices. In addition, other communication and / or data transmission devices such as, for example, Internet-enabled end devices, computers, television sets, notebooks, fax machines, etc. with associated radio units for communication traffic can be "on-air", ie via at least one air interface, components of the radio communication network as subscriber devices. The subscriber devices keep mobile or portable, that is, at changing locations in the radio network, but can also be arranged there where appropriate.

0014In FIG. 1, the two base stations BS1, BS2 are controlled or controlled by a higher-level radio network control unit RNC1 via associated data lines L1, L2. This monitors the allocation of radio resources in the radio cells CE1, CE2 of the base stations BS1, BS2. In the present exemplary embodiment, a large number of subscriber devices UE11 with UE51 are located in the radio cell CE1 of the base station BS1. Likewise, several subscriber devices UE21 with UE42 are currently present in the second radio cell CE2 of the base station BS2. The user equipment UE11, UE21, UE31 in the first radio cell CE1 and the user equipment UE42 in the second radio cell CE2 are assigned in advance to a predefinable group MC1, for which the reception of one or more group messages is to be provided in the most efficient manner.

0015In the context of the invention, the term “group of subscriber devices” is preferably understood to mean a classification according to technical service, that is to say, in particular, a division according to subscriber devices that permit multicast transmission or broadcast transmission. Furthermore, the subscriber devices in the radio cells of the radio communication network can also use a variety of other criteria, in particular, for example, the type of group message, such as Sports news, weather forecasts, etc., or reason for origin, etc. can be sorted or classified.

0016With many of the services and applications offered in modern mobile radio systems, it is particularly desirable to transmit messages not only to one but to two and more mobile radio subscribers. Examples of such services and applications are news groups, video conferences, video on demand, distributed applications, etc.

0017One way of transmitting the same message to different subscribers would be to send a separate copy of the data or messages to each recipient subscriber device. Although this technique would be easy to implement, it would be too expensive for large groups of subscriber devices. Since the same message would have to be transmitted via N (N = number of recipient subscriber devices of the message) individual connections (= unicast connections) and would be sent several times over common connection paths, this procedure would require an excessively high bandwidth.

0018In contrast, the so-called multicast transmission is a better alternative. The various subscriber devices to which the same message is to be transmitted are combined to form a group (multicast group) and this is assigned a single, common address (multicast address). The data to be transmitted are then only sent once to this multicast address. The respective multicast message to be transmitted is ideally sent only once via common connection paths from the respective transmitter to the receivers, here in particular mobile radio devices. It is not necessary for the transmitter to know where and how many receiver subscriber devices are hiding behind the specific multicast address. Which subscriber device belongs in particular to a specific, specific multicast group can be advantageously defined and managed on the network side. With the appropriate authorization, the respective subscriber device can also automatically register and / or log out of a specific multicast group.

0019In the so-called broadcast, messages are sent to all participants within a geographical area as a further alternative. Such an area can be determined, for example, by part of the overall radio network. As with multicast, the broadcast message is ideally only sent once over common connection paths from the transmitter to the individual receivers. Each subscriber device is preferably entered in a corresponding broadcast group if it wants to receive broadcast packets from this group. It can thus independently determine whether it wants to receive or reject all broadcast messages of the respective group or whether it only wants to receive certain messages.

0020In order to reduce the power consumption of mobile radio devices, if, for example, no connection is established or no longer exists, or there are no incoming calls or data, they fall into a type of "idle state". In UMTS this state is referred to as the so-called idle mode. The respective mobile radio device only listens to certain channels. Its position is only known "relatively imprecisely" on the network side. This means that the network does not know in which radio cell the respective mobile radio device is currently located. If such a mobile radio device, which is in idle mode, comes to an incoming call, for example, or data is transmitted, it is notified of it via certain radio channels to which it listens in idle mode, via certain procedures. The mobile radio device then sets up a signaling connection to the radio network, via which the radio resources on the air interface between the currently assigned base station and this mobile radio device are then allocated and configured for the transmission of the messages.

0021The layer model of the protocols on the air interface in UMTS is shown in FIG. 2 as an example for the user equipment UE11 in the radio cell CE1 of the base station BS1. The mobile station UE11 has a physical layer (Physical Layer) PL1, which is responsible for the processing of the data for transmission over the air interface via physical channels PCS on the transmission side, and on the receiving side for the received data to the media access control layer MAC1 (MAC = Medium Access) Control) passes on that they can be processed further by this layer. On the network side, the physical layer is located in the base station BS1, which is connected to the radio network control unit RNC1 (Radio Network Controller) via a fixed network connection. The connections between the physical layer and the MAC layer are called transport channels and indicate how the data is transmitted (e.g. on general channels that are heard by every mobile radio device in the radio cell of the base station, or on channels that are only dedicated to a specific mobile radio station). The MAC layer has tasks such as, for example, identifying the users for whom a data packet to be transmitted is intended if it is transmitted on general channels, and mapping logical radio channels onto the transport channels. For this purpose, the MAC layer adds control information on the transmission side, for example the identity of the respective mobile radio station, to the data packets to be transmitted, which it has received from a further, higher layer RLC (= radio link control). This RLC layer is designated RLC1 in the mobile radio station UE11. In the base station BS1, this RLC layer has the reference symbol RLC2. The connections between the respective MAC layer such as, for example, MAC1 in the user equipment UE11 and MAC2 in the radio network control unit RNC1 and the respectively assigned radio link control layer RLC1 or RLC2 (Radio Link Control). To map the logical radio channels to the transport channels, the respective MAC layer adds control information on the transmitter side, such as, for example, the identity of the respective mobile radio station to the data packets to be transmitted, which it has received from the respective higher RLC layer. At the receiving end, this control information is evaluated and removed from the data packets before it is forwarded to the RLC layer via the logical connections.

0022The respective RLC layer RLC1 or RLC2 is responsible for the monitoring of the data transmission, ie for the detection of missing data packets and possibly their renewed request. Several units can be defined in the RLC layer. Each RLC unit has at least one connection between the higher layers and the RLC layer (eg Radio Bearer RB). The RLC layer can also add control information to the packets it has received from higher layers. This control information is used at the receiving end, for example to assess whether packets are missing. They are removed from the packets before they are passed on to the higher layers. The radio resource control layer RRC (Radio Resource Control) is located above the RLC layer. Specifically, this is referred to here as RRC1 in the UE11 user equipment and with RRC2 in the associated radio network control unit RNC1. The respective RRC layer is responsible for the configuration of the layers below it and above all for establishing the connection. The connections between the respective RLC layer and the RRC layer are called SRBs (Signaling Radio Bearers) and are designated RRC1 for the user equipment UE11 and SRB2 for the radio network control unit RNC1.

0023In addition, the so-called RBs (radio bearers), which are used for the actual data transmission and represent the connection between the RLC layer and the application above, are located above the respective RLC layer. If packet data is transmitted, the packet data convergence layer (PDCP = Packet Data Convergence Protocol) is located above the respective RLC layer, e.g. here PDCP1 for the user equipment UE11 and PDCP2 for the radio network control unit RNC1, which is responsible, for example, for the compression of IP packets (Internet Protocol). Furthermore, the so-called broadcast multicast control layer BMC1 or, respectively, is located above the RLC layer of the user equipment UE11 and the radio network control unit RNC1 of the base station BS1. BMC2 (BMC = Broadcast Multicast Controller), which is used for the reception of any cell broadcast messages. Similar to the RLC layer, several BMC units can be defined in the respective BMC layer.

0024Subscriber devices (= UEs = user equipment) can be in different states. These states describe, among other things, whether the respective subscriber device has established a signaling connection to the network or whether it is in "idle" mode, which channels it is listening to and where it is known in the network:<ul id="ul0001" list-style="dash"><li>In the RRC state CELL_DCH state, dedicated resources are assigned to the respective mobile radio station and the mobile radio station is known at the cell level, ie the network knows in which cell the mobile radio station is located.</li><li>In the RRC state CELL_FACH state, the respective mobile radio station is assigned general resources which it shares with other mobile radio stations. In this state, the mobile radio station is also known at the cell level.</li><li>In the RRC state CELL_PCH state, the mobile radio station receives broadcast messages from the network and listens to the notification channels PICH (Paging Indicator Channel) and PCH (Paging Channel), via which the network can inform the mobile radio station that, for example, there are messages for it. In this state, the mobile radio station is known at the cell level.</li><li>The RRC state URA_PCH state is similar to the CELL_PCH state with the difference that the radio cell in which the mobile radio station is located is not exactly known to the network, but the network only has knowledge of which group of cells the mobile radio station could be in .</li><li>In idle mode, the mobile station also receives broadcast messages from the network and listens to the notification channels. In contrast to URA_PCH and Cell_PCH state, the radio resource control unit RNC has no knowledge of the mobile radio station itself and also not of whether the mobile radio station is located in one of the cells it controls.</li></ul>

0025Subscriber devices in idle and connected mode (CELL_DCH and CELL_FACH state) can be informed about various events using a specific mechanism. This can be, for example, an incoming call or the start of the transmission of data. The notification mechanism of the paging, ie the calling of a message pending to be sent, is preferably carried out in two stages. In the first step, the radio network notifies the respective mobile radio station by means of an indicator on the so-called paging indicator channel PICH, that is to say generally expressed on a specially provided, first separate radio channel, that messages are on the paging channel PCH, ie a further, second separate radio channel for the Mobile station ready for collection and then sent. In the second step, the respective mobile radio station at least partially reads out the PCH channel, which contains the actual notification, in particular the reason for the paging (paging type, paging record, paging cause). The respective subscriber device recognizes from this information whether it is a message that is specifically addressed to it and what the message is. Only if the subscriber device positively determines that the message to be transmitted is actually addressed to this subscriber device, does this establish a signaling connection to the radio network, via which the radio resources for the transmission of the messages are then allocated, ie assigned or provided, and configured.

0026The paging mechanism preferably differentiates between two types, which differ in the state of the respective subscriber device to be notified:<ul id="ul0002" list-style="dash"><li>Paging Type 1: This procedure is used to send paging information to certain UEs in idle mode, CELL_PCH or URA_PCH stage. The so-called Paging Control Channel (PCCH) is used as the logical channel. Higher layers in the network can cause paging, for example to set up a signaling connection.</li><li>Paging Type 2: This procedure is used to transmit dedicated, ie specific paging information to a specific subscriber device, abbreviated UE, in connected mode in the CELL_DCH or CELL_FACH stage.</li></ul>

0027In the context of the exemplary embodiment below, paging type 1 is of particular interest, since the case is considered here that a group of multicast subscriber devices or mobile radio devices without a dedicated connection to the network is to be informed about the arrival of multicast messages via a paging indicator . Possibly. the respective subscriber device in connected mode in CELL_DCH or CELL_FACH state can be informed in an analogous manner about the arrival of new multicast messages using the same method. The physical radio channel S-CCPCH (Secondary Common Control Physical Channel) in UMTS transmits information of the transport channel PCH (paging channel) and / or the FACH (Forward Access Channel). The paging channel PCH is transmitted via the S-CCPCH if a subscriber device is to receive paging information. The system information (SIB 5 and / or 6 = system information block 5 and / or 6) defines common radio channels, such as the S-CCPCH, which are made available for all mobile radio devices currently in a radio cell. Each S-CCPCH that is assigned to a subscriber device in the system information can preferably contain up to one paging channel PCH. Either one or more PCHs can be provided in a radio cell. Exactly one paging indicator radio channel PICH is preferably assigned to each PCH in a defined manner. In the event that more than one paging channel PCH (and associated, permanently assigned paging indicator radio channel PICH) is defined in the system information, the respective subscriber device carries out a selection based on which paging radio channel it then listens to, ie is ready to receive. For this, the respective subscriber device selects one of the listed radio channels S-CCPCH, preferably based on the specific International Mobile Subscriber Identity IMSI of the respective subscriber device:<maths id="math0001" num=""><math display="block"><mrow><mtext>"Index of the selected S-CCPCH" = IMSI mod K,</mtext></mrow></math><img file="EP1283648A1_D0001.tif" /></maths> where K is the number of S-CCPCHs listed in the system information that transmit a paging channel PCH. In other words, this means that the radio channels S-CCPCH, which only carry one FACH radio channel (Forward Access Channel), are not counted. The S-CCPCH are preferably indexed in the order in which they appear in the system information (0 to K-1). The radio channels S-CCPCH, which transport a paging channel PCH, are listed first in the system information. "Index of the selected S-CCPCH" identifies the selected S-CCPCH with the PCH and the assigned PICH that is to be used by the respective subscriber device, such as UE11.

0028The paging indicator channel or channel PICH is a physical channel that is used to transmit paging indicators. The PICH is preferably always assigned to an S-CCPCH in a defined manner, which transmits a PCH transport channel. FIG. 3 shows the structure of the frame structure RF of the PICH for the UMTS-FDD mode (Frequency Division Duplex). A PICH frame preferably lasts 10 ms and is in particular 300 bits ((b₀, b₁, ..., b₂₉₉) long. The first 288 bits (b₀, b₁, ..., b₂₈₇) used to transmit paging indicators. The remaining 12 bits are therefore formally not part of the PICH and should not be transmitted. This part of the PICH framework is reserved for future applications. Thus, while a first subsection BP of the frame structure RF of the transport channel PCCH is reserved for occupancy with paging indicators, a second subsection TO, which is at the end here, is still free.

0029Be in every PICH frame <i>Np</i> (<i>Np</i> = 18, 36, 72 or 144) transfer paging indicators. Which of the paging indicators (P_q) to which UE is assigned, is expediently calculated by higher protocol layers in the transceiver unit of the respective subscriber device and / or the respectively assigned base station or its assigned radio network control unit. The index, q 'indicates the position within the respective PICH frame and is preferably calculated as:<maths id="math0002" num=""><img file="EP1283648A1_D0002.tif" /></maths> 'PI' is calculated by higher layers for each UE in particular as:<maths id="math0003" num=""><math display="block"><mrow><mtext>PI = (IMSI div 8192) mod Np [3GPP TR 25.304]</mtext></mrow></math><img file="EP1283648A1_D0003.tif" /></maths>

0030SFN is the 'System Frame Number' of the P-CCPCH (Primary CCPCH) during which the PICH occurs. Because q is a function of<i>SFN</i> the position of the paging indicator assigned to a UE changes constantly. The IMSI (International Mobile Subscriber Identity) is assigned to each mobile device and uniquely identifies it. If a paging indicator is set to logic "1" in a specific PICH frame, the subscriber device (= UE) assigned to this paging indicator then reads the PCH of the corresponding S-CCPCH.

0031After a subscriber device has been informed of a new event using the paging indicator on the PICH, it will now be useful to find out the specific reason for this. This is particularly advantageous since, when calculating which paging indicator is assigned to which UE within a PICH frame, it can happen that two or more UEs listen to the same paging indicator. Whether the paging is now intended specifically for the respective subscriber device and what the exact reason for the paging is, the respective subscriber device learns by reading various information elements which are transmitted on the paging channel (PCH), which in turn is determined on the previously determined one S-CCPCH is shown: First, the subscriber device concerned in each case reads the information element 'paging type 1' on the respectively assigned PCH in accordance with FIG. 7. This informs, among other things, how many "occasions" there are for paging. It also receives a reference to the information element 'paging record' according to FIG. 8. This information element provides it, among other things, with information as to whether the event made known by the paging is intended for itself or for another subscriber device. Furthermore, it receives a reference to the information element 'paging cause' according to FIG. 9, in which the exact reason for the paging is then again described. This can include an incoming call or the start of a data transfer. The information elements shown in FIGS. 7, 8 and 9 with the member elements that are not underlined, that is to say marked separately, have already been specified in particular in accordance with the 3GPP specification [3GPP TS 25.331].

0032As already described above, the respective subscriber device now knows the reason for the notification and establishes a signaling connection to the network, via which corresponding resources for the transmission of the message or data are then made available.

0033According to the state of the art, mobile radio devices that are to be informed about the arrival of a message or an incoming call, the start of a transmission of data or similar events have so far been dedicated, that is to say mobile radio devices - specifically notified via so-called paging.

0034With various services and applications, messages should often not only be transmitted to one but to two and more mobile radio subscribers. This is generally the case, for example, with multicast, and especially with UMTS, in particular with multimedia broadcast / multicast service (MBMS). In the following, this is referred to as a "group service", whereby a "group service" can contain several groups (eg lottery, stock market prices, weather, ...) or classes.

0035According to the state of the art, the participants of such 'group services' would have to be informed about incoming messages via individual paging indicators assigned to the mobile radio devices (= 1 paging indicator per mobile radio device). For example 50 mobile radio devices in a radio cell, all of which are entered in the same group of a 'group service', would be informed of the arrival of a corresponding message using 50 specific paging indicators.

0036In contrast, the core of the principle according to the invention is the introduction of a group paging indicator for "group services" in which a message is to be sent to a group of subscribers, in particular multicast services.

0037This group paging indicator is advantageously used to indicate the arrival of a group of one or, preferably, several mobile radio devices which, for example, want to receive certain services (in which a message is to be sent to a group of subscribers (in particular multicast services)) such group messages or the like - To inform occasions.

0038This “group paging indicator” is therefore not specifically assigned to an individual subscriber device compared to the prior art, but rather to a group of one or more subscriber devices. These subscriber devices or UEs expediently have in common that they all use the same "group service", in particular multicast service. This means that they belong to at least one group of recipients of a certain "group service", in particular multicast service (= only 1 paging indicator per service, in particular multicast service).

0039The following procedural steps are useful to ensure group paging:<ul id="ul0003" list-style="dash" compact="compact"><li>In a first step, the respective mobile radio device (UE), which is subscribed to a 'group service', in particular a multicast service, determines which of the S-CCPCHs of a radio cell that transport a PCH appropriately hears it.</li><li>In a second step, a group paging indicator is determined within a PICH frame, which is assigned to the respective group of mobile radio devices (UEs) that belong to a "group service", in particular multicast service.</li><li>In a third step, existing information elements, from which a mobile radio device learns the reason for the paging, are preferably expanded so that a mobile radio device recognizes, inter alia, for which multicast group a message is being sent. These information elements may also contain further information.</li></ul>

0040From the system information, the respective subscriber device receives information about the S-CCPCHs that are provided in a radio cell and whether they are transporting a PCH. A PICH is preferably permanently assigned to each S-CCPCH. The subscriber device then determines or calculates which S-CCPCH / PCH and PICH it suitably listens to and which group paging indicator of a PICH frame is assigned to a 'group service', in particular multicast service.

0041After receiving a "group paging indicator", in particular multicast paging indicator, which is transmitted on the PICH, the mobile radio device then appropriately listens to the assigned PCH. Information elements are then transmitted on the PCH, which advantageously contain information about which group, in particular multicast group, the incoming message is directed to (see information elements paging type 1, paging record, paging cause in FIGS. 7, 8, 9). . If a mobile radio device belongs to the corresponding group, a signaling connection to the mobile radio network is then set up, via which the resources for the transmission of the message are then allocated.

0042It is advantageous here that all mobile radio devices are notified of the arrival of a group message, in particular a multicast message, by means of a common “group paging indicator”. According to the prior art, N (N = number of MC subscribers in the radio cell) paging indicators would have to be used for this, which would be too complex and too ineffective.

0043An expedient sequence of the method according to the invention for notifying a group of recipients about a common “group paging indicator” is shown in FIG. 4:

0044The respective subscriber device (= UE) receives system information SI from at least one component, in particular base station of the radio network UT (in UMTS this is UTRAN = universal terrestrial radio access network) and reads from it which S-CCPCHs are transmitted in the radio cell, and which of these S-CCPCHs transmit a PCH. A PICH is permanently assigned to each S-CCPCH that transmits a PCH. In a step SUT, the network determines beforehand on which S-CCPCH group information is to be transmitted. In a corresponding step SUE, the UE determines which of the S-CCPCHs / PCHs and associated PICHs it expediently listens to. Possible variants for this determination are given in a section below.

0045If the transmission of a group message GN1 for a group of the 'group service' is imminent, the network (, in particular UTRAN,) UT sends a corresponding group paging indicator signal GPI on the previously selected PICH (2, Fig.4). In the next step RGPI, all UEs that are registered to a group of the "Group Service" read this group paging indicator signal GPI and recognize that a group message GN1 is now to be transmitted. Which group paging indicator is specifically assigned to the respective 'group service' within a PICH frame is determined beforehand in the network and in the UEs. Possible variants for this are given in a section below.

0046In order to find out whether the respective incoming group message specifically affects the respective subscriber device because it is a member of the corresponding group, the latter reads the paging information PIN (in particular the information elements paging type 1, paging record and Paging cause according to FIGS. 7 and 9), which are transmitted on the PCH. In the field or Information element paging record includes, in particular, a group identity GI (see FIG. 9) which identifies a specific group of the "group service". Further possible variants are given in the following sections.

0047If the respective subscriber device recognizes on the basis of the transmitted paging information PIN that the pending or arriving group message GN1 is of no interest to it, it falls back into the state in which it was previously. If the UE recognizes that the incoming group message GN1 is of interest to it, it now sets up a signaling connection SV via which the resources for the subsequent transmission of the group message are then allocated and configured.

0048There are various options for determining on which S-CCPCH or PCH and assigned PICH a subscriber device that is registered for a 'group service' receives signaling data:<ul id="ul0004" list-style="dash"><li>In the most expedient variant, all UEs that are registered for a 'group service' listen to the same S-CCPCH. The information on which S-CCPCH the UEs have to listen to is in the System Information (SIB 5/6). For this purpose, the system information is expediently expanded by additional information elements. Figure 5 shows this using the example of the information element "Secondary CCPCH system information" [3GPP TS 25.331, Chapter 10.3.6.72], which is transmitted in SIB 5 and 6. In addition to the state of the art, a so-called "group service indicator" is added, which indicates whether and which S-CCPCH, which transports a PCH (and associated PICH), is used for the transmission of "group service" information. The changes compared to the prior art are marked.</li><li>Another possibility is that the same, predefined S-CCPCH is always used for the transmission of information relating to a recipient group. For example, this can always be the first or the last of the S-CCPCHs defined in the system information. The assigned PICH transmits the group paging indicator. The S-CCPCH transmits the PCH, via which information about the reason for the paging is preferably transmitted.</li><li>UEs that are entered in a 'Group Service' all listen to the same S-CCPCH. The higher protocol layers of a UE calculate which S-CCPCH it should listen to. A "group service" identity is advantageously used for this calculation, which is expediently known or made known to the corresponding UEs. When using a group-specific (<u>Not</u> 'Group service' -specific) Identity such as the IMGI (International Mobile Group Identifier) ​​is expediently ensured when calculating the respectively assigned S-CCPCH that despite different groups of identities of the same 'group service' the same S-CCPCH ( and associated PICH) is calculated. In the event that UEs calculate different S-CCPCHs for the transmission of group paging information, the corresponding information is expediently transmitted on each of these S-CCPCHs. The assigned PICH transmits the group paging indicator such as GPI1. The S-CCPCH transmits the PCH, via which information about the reason for the paging is transmitted.</li><li>"Group service" information is transmitted on all S-CCPCHs transmitted in a radio cell, which transmit PCHs. This means that the 'group paging indicators' are transmitted on all assigned PICHs. Information on the reason for the paging is therefore advantageously transmitted on all PCHs, which, however, requires a relatively high level of redundancy.</li></ul>

0049The following options for selecting a group paging indicator within a PICH frame are expedient in order to be able to signal the subscriber devices of an addressed, affected group about events relating to a 'group service' or another pending group message (for example, incoming message, etc.):<ul id="ul0005" list-style="none" compact="compact"><li>If a group paging indicator is used for all groups of the 'group service', a UE is informed when a message arrives that it is now available. In addition, two other secondary options should be considered here:<ul id="ul0006" list-style="dash" compact="compact"><li>If you use one group paging indicator per group of a 'group service', a UE that is registered to the 'group service' can already recognize from this group paging indicator whether it is a message of interest (disadvantage: with many multicast (MC -) Many group paging indicators are required for groups).</li><li>If you use a group paging indicator for certain MC groups (subset of all MC groups of a 'group service'), a UE that is registered for the 'group service' can pre-select on the group paging indicator whether the incoming message is specific to it, ie for is interesting. The subscriber device then only learns from the paging cause for which group the message really is.</li></ul></li></ul>

0050When calculating or determining which paging indicators are used for which 'group services' within a PICH framework, it may be expedient that the same group paging indicator is assigned to other UEs that listen to the same PICH as rarely as possible. This applies both to UEs that belong to other 'group services' and to UEs which are not registered to any 'group services'. This has the advantage of increasing the efficiency of the process.

0051This can be achieved, for example, by the fact that<ul id="ul0007" list-style="dash" compact="compact"><li>Paging information from different MC services and groups can be sent on different PICHs and PCHs.</li><li>different DRX cycles are used for PICHs, the 'group paging indicators' and PICHs, which do not transmit 'group paging indicators'. PICHs are not received by UEs in every frame, but at regular intervals, so-called DRX cycles (e.g. to save energy). By using different DRX cycles for PICHs with and without 'group paging indicators' one can prevent "double assignment" of paging indicators.</li></ul> However, if the same paging indicator is assigned to two or more UEs, it is expedient that these UEs read the reason for paging and for whom the event is actually interesting from corresponding information elements.

0052The calculation or determination of which group paging indicator is assigned to which 'group service' within a PICH frame is preferably carried out by higher layers. For example, a group identity (eg IMGI, International Mobile Group Identity) can be used to calculate the positions 'q' of the respective group paging indicator, such as GPI1. The formula for calculating 'GPI1' could then look like this, for example:<maths id="math0004" num=""><math display="block"><mrow><mtext>GPI1 = (IMGI div 8192) mod Np</mtext></mrow></math><img file="EP1283648A1_D0004.tif" /></maths>

0053Another possibility is that the same predefined group paging indicator is always used for 'group service' purposes. For example, this can always be the first or last group paging indicator in a PICH frame or any other. Which group paging indicator is reserved for 'group services' within a PICH frame can be made known, for example, by expanding corresponding information elements. In Figure 6 6, the information element, PICH Info '[3GPP TS 25.331, Chapter 10.3.6.49] is expanded by an additional information GPI with the name, Group PI'. This information element indicates the position of a group paging indicator within a PICH frame that is assigned to a 'group service'. For this exemplary embodiment, the change is applied only for FDD (Frequency Division Duplex). The changes compared to the prior art are marked by underlining the additional information signals.

0054It would also be possible to use the bits TO of a PICH frame (see FIG. 3) that have not yet been used for “group service” purposes.

0055By expanding the information elements responsible for paging, the reason for the paging should be displayed in an advantageous manner, as well as the group of the "group services" relating to the paging. This is shown below using the example of the multicast service.

0056One possibility is to expand the information element 'paging record' [3GPP TS 25.331, chapter 10.3.3.23] from FIG. 9 by an additional element GI (“multicast group identity”), in which the multicast group of the “multicast service” is then identified becomes. In addition, the 'paging record' refers to the information element 'paging cause' [3GPP TS 25.331, chapter 10.3.3.22], which expediently expands by an additional element TMS ("Terminating Multicast Session"), which specifies the reason for the paging, namely an beginning multicast transmission (see Figure 9). The changes compared to the prior art are each marked by underlining the respective additional information signal.

0057A further possibility is that when reading the information element 'paging cause', which according to the invention contains an additional element "terminating multicast session" as described above, a UE receives a PTMS reference according to FIG. 10 to a further new information element "terminating multicast session". This information element now contains the multicast group for which the incoming message is intended, represented by a multicast group indicator GI. The changes compared to the prior art are marked. Compared to the option described first, the information element 'paging record' need not be changed here.

0058It may also be expedient, in the system information signals (see FIG. 5) of the radio communication system, which are emitted by at least one of its network elements, to also carry at least one indicator signal, such as GSI, on which of the radio channels, in particular secondary common control physical channels , at least one transport channel (PCH) with information about the respective group message to be transmitted is transmitted.

0059The following acronyms are referred to in the description, which are listed here in summary: (Basically, plural formation takes place by appending an 's', eg: one RB, two RBs)<dl id="dl0002" compact="compact"><dt>BMC</dt><dd>Broadcast / Multicast Control</dd><dt>DCH</dt><dd>Dedicated channel</dd><dt>DRX</dt><dd>Discontinuous reception</dd><dt>SUBJECT</dt><dd>Forward access channel</dd><dt>FDD</dt><dd>Frequency division duplex</dd><dt>IMSI</dt><dd>International Mobile Subscriber Identity</dd><dt>IP</dt><dd>Internet Protocol</dd><dt>MAC</dt><dd>Medium access control</dd><dt>MC</dt><dd>Multicast</dd><dt>MS</dt><dd>Mobile station</dd><dt>P-CCPCH</dt><dd>Primary Common Control Physical Channel</dd><dt>PCH</dt><dd>Paging channel</dd><dt>PDCP</dt><dd>Packet Data Convergence Protocol</dd><dt>PI</dt><dd>Paging indicator</dd><dt>PICH</dt><dd>Paging indicator channel</dd><dt>RB</dt><dd>Radio bearer</dd><dt>RLC</dt><dd>Radio Link Coritrol</dd><dt>RRC</dt><dd>Radio resource control</dd><dt>S-CCPCH</dt><dd>Secondary Common Control Physical Channel</dd><dt>SFN</dt><dd>System frame number</dd><dt>SRB</dt><dd>Signaling radio bearer</dd><dt>UE</dt><dd>User equipment</dd><dt>UMTS</dt><dd>Universal Mobile Telecommunication System</dd><dt>URA</dt><dd>UMTS routing area</dd></dl>