Dynamic allocation of radio resources in packet switched communications-system

Method for realizing dynamic allocation of wireless resources in packet switching communication system

The present invention is related to mobile communication, such as cellular communication. The present invention is particularly suitable for, but not limited to, a global system for mobile communication (GSM) type mobile communication system.

An example of a cellular communication system that provides voice transmission services is: MOTOROLA (trademark)'s integrated digital enhanced network system or iDEN (trademark) system. This system includes enhanced basic transmission and reception systems (EBTSs) at the cell location, which connect mobile terminals to fixed network equipment via a TDMA wireless interface, which in turn is connected to controlling base station controllers (BSCs). BSCs provide a connection with a mobile switching center (MSC), which uses ordinary circuit switching provided by the public switched telephone network (PSTN); BSCs also provide a city packet switching (MPS), which can provide the exchange of sending services. A sending application processor (DAP) coordinates and controls sending communications by registering the identification and location of mobile terminals that are active in the system.

The iDEN system provides voice transmission services and line switching call services; and other data communication services, such as short message services.

US-A-5,416,770 describes a voice-transmitting cellular communication system, in which voice data packets are sent via a continuous connection in the frame. Communication is established between a large number of communication units. The method used is to repeat the transmitted data packets and distribute these repeated packets to the identified target base station.

US-A-5,448,620 describes a mobile terminal that can operate in two modes, voice transmission mode and telephone interconnection mode, a well-known GSM network called Public Land Mobile Network (PLMN), and its brief description is as As shown in Figure 1. A mobile switching center (MSC) 2 is connected to multiple base station controllers (BSCs) 4 through communication lines. These BSCs4 are geographically distributed in the area served by the mobile switching center 2. Each BSC4 controls one or more Basic Transmitting and Receiving Stations (BTSs) 6 far away from the BSC, which are connected to the BSC by further communication lines. Each BTS 6 transmits and receives wireless signals with the mobile station 8 located in the service area of this BTS. This area is called a "unit". A GSM network provides a large number of such units, which ideally continuously provide continuous coverage of the entire network territory.

One mobile switching center 2 is connected to other mobile switching centers of the mobile communication network 10 through communication lines, and to other networks, such as a public switched telephone network (PSTN), not shown in the figure. The mobile switching center 2 has a home location register (HLR) 12, which is a database for storing the user's authentication receipt, including the International Mobile Subscriber Identity (IMSI), which is unique to each mobile station 8. This IMSI is also stored in the subscriber identity module (SIM) of the mobile station together with other user-specific information.

The mobile switching center also provides a visitor location register (VLR) 14, which is a database that temporarily stores user authentication data of mobile stations active in its area.

GSM was originally designed to support full-duplex, circuit-switched voice calls.

A new functional unit is added to the technical specifications of the GSM2+ stage, called the Advanced Voice Call Item (ASCI), which is used for group calls and broadcast to the members of a group. In order to establish a broadcast group call, an originating mobile station sends a service request including the identity of the requested group to the MSC, and the MSC authenticates the user with the VLR.

If the authentication check is successful, the MSC obtains the identification data of the members of the group from the group call register. Using this information, the MSC establishes a connection between the receiving mobile station and a group call sender. Each unit where the receiving mobile station is located sends out an announcement call, including the identification of the group being called and the description of the broadcast channel assigned to this group call. This group call transmitter sends group call data to each unit assigned to the channel for broadcasting.

Another functional unit added to the GSM system of the GSM2+ stage technical specifications is the General Packet Radio Service (GPRS).

GPRS provides a packet-based service to transmit high-speed and low-speed data and signals to effectively cover the GSM wireless network. It is designed to support a certain range of data transfers, from intermittent and burst data transfers to occasionally large data transfers. It faces Internet services, email services and other services.

GPRS includes two facilities: point-to-point (PTP) and point-to-multipoint (PTM) data packet transmission. In PTM data packet transmission, data packets are broadcast to all units in a specified geographic area. At this time, GPRS transparently transmits data packets, which is different from the situation where the data packets are correctly received by its destination station. At this time, there is no knowledge of the data packet content on the network.

The GPRS wireless interface is placed in the variable TDMA time slot of the GSM physical wireless interface; the GSM physical wireless interface is the traffic channel and signaling channel used for circuit switching. The same GPRS radio resource is shared by all mobile stations in a unit, and the radio resource is saved by the mobile station or used by the mobile station only when there are data packets to be sent.

Packet-oriented network facilities include a packet-switched packet data network composed of GPRS support nodes (GSNs) connected by a GPRS backbone network; including a gateway GPRS support node (GGSN), which is used to route data packets to and from the outside Packet data protocol network (PDP), such as a network using TCP/IP, X.25 or similar protocols.

One aspect consistent with the present invention is that it provides a method of controlling communication between user stations, who use a mobile communication system with a wireless interface. Said method includes: providing a data packet handler (Data PacketHandler) connected to the packet data network; maintaining control data, which indicates the call status between the first user station and the second user station; dynamically allocating wireless The transmission of resources to data packets that carry the call data through the wireless interface; therefore, the total amount of allocated wireless resources varies with the total amount of call data to be sent by the call at different points Change; Finally, the data packet processor is used to control the data packet transmission between the first and second user stations according to the control data.

The status of the call can be stored in the memory on the network side to allow control of communication between mobile stations. The functions provided by the packet data network and the characteristics of wireless resource allocation and control make it possible to transmit data through a call, even when the data transmission is intermittent, there is no requirement for an ongoing circuit-switched connection between user stations , The transmitted data can be voice call data or image call data.

The present invention further provides a method for processing data transmission in a GSM-type mobile communication system. The method is composed of: receiving the first data packet from the first user station, the data packet containing a receiver ID; mapping the received User ID to a packet network protocol address, based on this address to guide the second user station, which is identified by the gateway GPRS support node; finally a second data packet is transmitted to the said gateway GPRS support node, this second data packet contains all Said packet network protocol address.

This function allows data packets to be transmitted between GPRS user stations with a known receiver ID instead of a packet network protocol address (it may only be allocated temporarily), which can be used by the first user station to identify the second user station.

The present invention further provides a method of communication between user stations using a mobile communication system, each said user station being composed of a camera for capturing user images and a display for displaying remote user images. The method includes establishing a data transmission connection between user stations and controlling the connection to work in half-duplex mode; that is, the user station can only complete one of the two: when it is sufficient to receive or send an image The first cycle of image data only receives or sends only image data; then, in the second cycle after the first cycle, another one receives only or only sends video image data. This cycle is also sufficient to send or receive the image data that forms an image. Image data.

The present invention further provides a mobile station suitable for video image communication. The mobile terminal adopts a half-duplex communication mode controlled by a data processor; this communication mode prevents the transmission of video image data when receiving video image data, And it is allowed to send video image data in a certain period selected by the user.

The communication methods and mobile stations provided by these aspects can be used in a video conference in a novel and convenient way. In order to limit the communication to a half-duplex mode, the bandwidth and power requirements of the mobile station can be reduced when calls are required.

In addition, running in the sending communication mode, the video data is distributed among a group of receivers, which makes it possible for each receiver to send and receive data. A user can catch the call to send video data, this data is received by the rest of the participants, the call can then be caught by different participants.

Other aspects of the present invention are specified in the appended claims, and their characteristics will be apparent from the following description.

The present invention will be described in detail with the following examples with reference to the drawings, in which: Fig. 1 is a schematic block diagram of a well-known public land mobile network; Fig. 2 is a schematic block diagram of the first concrete implementation of the present invention; 3 A schematic block diagram of a mobile communication network arranged in accordance with the present invention; FIG. 4 is a schematic illustration of a group call record for connection in an embodiment of the present invention; FIG. 5 is a schematic illustration of a stored mobile user record in an embodiment of the present invention; Figures 6, 7 and 9 are descriptions of the flowcharts performed by the mobile station in relation to the embodiments of the present invention; Figures 8, 10 and 11 are descriptions of the flowcharts performed by the data packet processor relating to the embodiments of the present invention; Figure 12 is the description of the flowcharts performed by the data packet processor of the embodiment of the present invention. A schematic block diagram of a mobile station of the second embodiment of the invention.

Referring to Fig. 2, the mobile station conforming to GSM in the embodiment of the present invention is a mobile phone, which consists of a transmitting/receiving antenna 16, a radio frequency transceiver 18, a GPRS module 19, including a grouping/splitting group device. And a memory buffer, a voice codec 20 connected to the speaker 22 and microphone 24, a processor circuit 26 and its related memory 28, a liquid crystal display 30, a manual input port (keyboard) 32 and a call Button (PTT) 34. This mobile station is connected to a removable Subscriber Identity Module (SIM) via an electrical connection, not shown in the figure.

Figure 3 is a schematic illustration of a GSM-type PLMN arranged according to an embodiment of the present invention. This PLMN includes GPRS support nodes, which include one or more serving GPRS support nodes (SGSNs) 40, and a gateway GPRS support node (GGSN) 44. This PLMN includes all the components described in Figure 1.

The mobile station 8 can make a circuit-switched call through the MSC2 immediately after entering the service unit, using the previous technology.

The GGSN 44 is an interface node that provides the PLMN and an external packet data network 46, such as a TCP/IP network. It contains the routing information of GPRS users active in the PLMN. This routing is used to send data packets from the packet data network to the current connection point of the mobile station in the PLMN. This data packet is called the Protocol Data Unit of the Packet Data Protocol (PDP). PDUs). GGSN provides a mapping function, which maps the packet data protocol (PDP) address of the packet data network 46 to identify the mobile user to the identity of the mobile station in the PLMN to identify the mobile user. The PDP address of a mobile user is used in the packet data network 46 The standard address mechanism of the individual network layer services is consistent, such as an IP4 address, an IP6 address or an X.121 address.

A mobile user can be assigned a permanent or "static" PDP address, which is stored in mobile station 8 and HLR12; it can also request a temporary or "dynamic" PDP address, which is allocated by GGSN44 upon request. For it.

SGSNs 40, 42 are called serving GPRS support nodes, and these nodes serve the mobile station 8 in their routing area. When a mobile station is registered to the GPRS service, the SGSN establishes a mobility management text that contains the mobility and security information related to the mobile station. The SGSN also establishes a routing text, which is called "PDP text" in GPRS, and together with the GGSN, enables the mobile station 8 to access the packet data network 46.

The functions of SGSN and GGSN can be combined in the same physical node, or they can exist in different physical nodes respectively.

The packet data network 46 can be the public Internet, an internal Internet connection (Intranet), or a dedicated line. The packet data network 46 may also provide connections with other components, such as the GGSN 56 or fixed terminals 58 of other PLMNs.

Therefore, using the additional functions of the SGSNs40 and GGSN44 in the PLMN and the GPRS module 19 in the mobile station 8, the mobile network and users are GPRS capable, and the mobile users can send and receive packet-type data accordingly. For example, mobile users can use mobile stations to access Internet web pages. To this end, they use terminal equipment to connect to the mobile station on the public Internet; pass through the gateway function provided by GGSN44; and by other parts of the network, including SGSNs40, 42, BSCs4, BTSs6 and The packet transmission function provided by the GPRS wireless interface.

The GPRS wireless interface is described in the GSM03.64.5.1.0 version with the title "Digital Cellular Communication System (Phase 2+)"; General Packet Radio Service (GPRS); the entire description of the GPRS wireless interface, Phase 2 is published by the European Institute of Communication Standards , Its content is included here by reference.

The GPRS architecture and transmission mechanism, mobile management function, network management function, wireless resource function, packet routing and transmission function, and GPRS transmission and storage information function are described in version GSM03.60.5.2.0, titled "Digital Cellular Telecommunications System (Phase 2+)"; General Packet Radio Service (GPRS); Service Description; Phase 2 is published by the European Institute of Communication Standards, and its content is included here by means of examination.

In addition to standard GPRS facilities, the mobile communication system of the present invention also includes a packet sending processor 48, a packet memory 50, a packet user database (PUD) 52 and a service management terminal 54.

The packet processor 48 is responsible for establishing a virtual connection between GPRS users of the PLMN, and copying the packets when the data packets are to be distributed to the group users.

The packet memory 50 is responsible for storing those data packets, which are to be distributed to GPRS users in the PLMN, but these users are inaccessible when the packet processor 48 receives the data packets.

The packet user database 52 saves service data records, and the packet processor 48 uses it to establish and manage virtual connections between GPRS users in the PLMN. The service management terminal 54 is used to modify the service data in the PUD 52.

PUD52 keeps call group records to identify members of a call group. Refer to Figure 4, which shows a call group record model. The domain of a single call group is identified by the call group ID containing domain 60. Two or more mobile station IDs, MSID1, MSID2...MSIDn are contained in the domain In 62, the ID field 62 of each mobile station has a related call catching field 64 flag, which is used to indicate that the related mobile station is currently catching the call group.

In addition to the call group record, the packet user database 52 also stores the identification record of each mobile user effectively subscribing to the GPRS virtual connection service in the PLMN in the present invention. Referring to Figure 5, each such user has a mobile user record, including field 66 to store the permanent mobile station ID; field 68 to store an assigned PDP address, if the mobile user is current; field 70 to store Call group ID, if this mobile user is current. If the PDP address field 68 is empty, it indicates that the mobile station is not currently connected to GPRS service. If the current call group ID field 70 is empty, it means that the user is not currently participating in a GPRS virtual connection call.

Figure 6 illustrates the process of completing the GPRS virtual connection service in the mobile station 8 for participating in the GPRS virtual connection of the present invention.

In order to apply this GPRS service, the user initiates the GPRS registration process from the mobile station 8, step 100.

The GPRS registration signaling process is described in the GSM03.60V.5.2.06.5 part, titled "connection function", which is specifically included here by reference. This part also refers to section 9.2.2 in the same file, titled "Activity Process", which describes the PDP body activity process during registration, and this part is also specifically included here by reference.

After completing the GPRS connection, the mobile station is in a "ready state". In this state, packet transmission via the GPRS radio interface between the mobile station 8 and the PLMN can occur; at the same time, the mobile management text is established in the mobile station and the SGSN40. Then, the mobile station activates its PDP text and sends a request for "activate PDP text" to the SGSN40. If the mobile station uses a static PDP address, it transmits its static PDP address in the "Activate PDP Text" request.

The SGSN 40 inquires the HLR 12 storing the reservation information of the GPRS user in order to check whether the mobile station 8 is allowed to activate the PDP address included in the request. If allowed, the SGSN sends a'create PDP body' request to GGSN44, which creates a new entry in the PDP body table stored in HLR12 under the name of GGSN44. This PDP text table contains the identification of the mobile station and the PDP address assigned to the mobile station. It enables the GGSN 44 to map between these two identifications, so that data packets can be transmitted between the SGSN 40 and the packet data network 46.

If the mobile station 8 does not use a static PDP address, the'create PDP body' request is sent to the GGSN 44 by the SGSN 40, and a dynamic PDP address is allocated in the GGSN, and this address is sent to the mobile station 8 via the SGSN 40.

Regardless of whether the mobile station uses a static PDP address or a dynamic PDP address, in each case a PDP address is always given to the mobile station, by which the packets identified as coming from the packet data network are transmitted. The routing in the PLMN is provided by the GPRS data packet packaging process, which is removed from the data packet in the GGSN 44 and the mobile station 8. The packaging function is described in section 9.6 of the file GSM03.60V.5.2.0, which is included here by reference. GPRS transparently supports the transmission of PDP PDUs between external networks and mobile stations. One packaging method (here called GSN-GSN packaging) is used for the GPRS backbone network between GSNs in PLMN, and the other (here called SGSN-MS packaging) is used between SGSN40 and mobile station 8. GPRS connection.

GGSN44 is arranged in this way, once the PDP text item of a newly registered GPRS user has been established by GGSN44 in HLR12; GGSN44 sends a registration message to the packet processor, notifies the packet processor 48, between the mobile station identification and the assigned PDP address The mobile station identity is stored in the field 66 of the mobile station record in PUD52, which is the permanent identity of the user in the PLMN and the assigned PDP address. After receiving the registration information, the packet processor 48 enters the PDP address of the mobile user record field 68 of the said user.

Once registered to the GPRS service, the mobile station can send or receive data packets from the packet processor 48.

The data packet starting from the mobile station 8 is sent to the SGSN40 via the wireless interface, BTS6, BSC4. When the SGSN40 receives a packet completely and correctly, its GSN-GSN packs the packet into a GPRS backbone network packet and sends it to the GGSN44. The GGSN 44 unpacks the packet, and uses the PDP address to forward the data packet to the packet processor 48; this PDP address is the packet start address assigned to the sender at the head of the data packet.

The data packet starting from the packet processor 48 is sent to the mobile station 8 with the additional assigned PDP address, this address is reserved in PUD 52 as the receiver address; this PDP address is appended to the header of the data packet as the destination address . This data packet is sent to the GGSN 44 via the packet data network 46. In the GGSN44, the PDP address of the receiver is read out, and the SGSN serving the mobile station at the receiving address is identified by the routing data stored in the HLR12. Then, this packet data is packaged by GSN-GSN and sent to the identified SGSN. The SGSN separates the packaging of the GPS backbone network, and the original data packets are packaged by the SGSN-MS and sent to the mobile station 8 via the BSC4, BTS6 and GPRS wireless interfaces.

When the mobile station 8 receives this packet, it deletes the SGSN-MS package and processes this data packet. If the data packet is a voice data packet, a series of packets are reassembled, and a voice signal is generated in the mobile terminal.

The user can initiate a call from a man-machine interface of the mobile station 8, such as the auxiliary keyboard 32. The establishment of this call is to select the call group where the mobile user is located from the stored call group table, and one of the call groups is used for this. The virtual connection of the call will be established. This selection is part of the initiation of the call setup-send process, step 102. Step 102 will be described in Figure 7 below.

Once registered with the GPRS service, the mobile station 8 can receive the call setup-receive request from the packet processor 48, and a process it initiates will be described in FIG. 9 below. Once participating in a call, the mobile station 8 can start receiving data packets of the call, step 106, and start sending data packets of the call, step 108, which will be described in FIGS. 7 and 8 below. In addition, it is possible for the user to end participating in a call through a human-machine interface of the mobile station 8, such as the interactive keyboard 32, step 110; it causes the mobile station to send an end participation request to the packet processor 48, step 112; and from it Delete the call group ID from the current call record, step 114.

If desired, the user can also log out from the GPRS service. In step 116, it generates a log out process completed by the mobile station 8, and step 118 includes deleting the PDP address assigned to the user stored in the HLR record by the GGSN44. The GGSN44 is arranged in this way. When it receives a logout message from the SGSN40, the GGSN44 also sends a logout message to the packet processor 48. It generates a process that deletes it from the mobile user record field 68 reserved for the user in PUD52. PDP address previously assigned.

Referring to Figure 7, when the user first instructs the mobile station 8 to establish a call to a specific call group, the mobile station 8 sends an establishment request containing the selected call group ID as one or more GPRS data packets to the packet. Processor 48, step 200; to select a call group is to press the PTT button 34, and the call group is selected from the call group table stored in the SIM of the mobile station 8. The call processing guidance process will be described in Figure 8 below. And it depends on the success of the call establishment process to determine whether the packet processor 48 sends an establishment confirmation message to the mobile station 8 within the time limit. If the call establishment confirmation is not received within the time limit in the mobile station, step 202, the mobile station returns to the normal GPRS registration state, and the mobile station 8 can try to send another call establishment request.

If within the time limit, the establishment confirmation from the packet processor 48 is received, the mobile station 8 provides an audio or visual indication to the user indicating that a virtual connection has been established, step 204. In addition, the mobile station puts the call group ID selected by the user in the current call record, step 206.

At this time, when the PTT button 34 is kept pressed, the user can speak with the microphone 24 to transmit voice data. This voice signal is encoded by the codec 20 and sent to the GPRS module 19, where the voice data is grouped and registered, step 208, and packaged in SGSN-MS so as to be sent by the wireless frequency transceiver 18 through the GPRS wireless interface to Go to the packet processor 48, step 210.

Once the PTT button 34 is released, step 212, the mobile station 8 generates a transmission end message, and transmits it to the packet processor 48 in the form of a data packet, step 214.

Referring to Figure 8, when a call setup request is received, in step 300, the packet processor 48 uses the call group ID contained in the call setup request to retrieve the recipient record from PUD 52, which identifies the current call setup message capable of receiving Recipients, step 302. Each mobile station in the call group record has an associated mobile station record, which is identified by the mobile station ID contained in the call group record. The record for each mobile station contains a PDP address, but does not have the current call group ID; a setup message is sent by the packet processor using the mobile station to retrieve the PDP address, step 304. The mobile station records that either do not contain the assigned PDP address or contain the current call group ID, and are placed in the call waiting table in PUD 52, and then the voice data packets received by the same call group are sent to the packet memory 50 for storage. This is a situation where a potential receiver has not yet registered for the GPRS service; when the receiver completes the registration later, the packet processor 48 will receive a notification; then, a setup message is transmitted, allowing the previously impossible receiver to receive and save The data in the packet memory 50, if so desired. Similarly, if the potential recipient is unable to receive due to participating in a different call, once the packet processor 48 receives an end participation message from the potential recipients previous call; the packet processor responds by transmitting an establishment message To the previously impossible recipient, this recipient is allowed to receive the data originally retained in the packet memory 50, if so desired.

If the packet processor does not receive the receiver's confirmation within the time limit of sending the setup message, step 306, the call establishment is unsuccessful, the packet processor ends the process and does not store any information about the call in the PUD 52 or the packet memory 50 Create the data of the attempt.

Otherwise, the packet processor 48 sends the call group ID into the domain 70 of the current call group. This is for both: the sender of the call establishment request and the recipient of the call establishment message, the latter has confirmed the call establishment, step 308, and more, The recipient confirms the call establishment, and the current call group ID enters the call group ID field 70 of each additional recipient.

In addition, the packet processor 48 sets the call catch flag field 64 in the call group record corresponding to the mobile station ID of the sender of the call establishment request, and sends an establishment confirmation message to the sender. Step 310 indicates that the sender can now send Sound data is available, step 310.

Once the sender receives the establishment confirmation message, as described in the relevant part of FIG. 7, the sender presses the PTT button 34 and starts to transmit the voice data packet received by the packet processor 48, step 312. If there is more than one participant participating in the call, step 314, the packet processor 48 copies the content of each group to each participant, step 316.

Then the received packet is transmitted to each participating recipient, step 318, until the end message is transmitted from the mobile station 8 that sent the voice packet, step 320. Once the end message from the sending mobile station 8 is received, an end message is transmitted to each receiver, step 322, and the call capture flag in the call group record field 64 corresponding to the sending mobile station ID in PUD 52 is deleted, step 324.

Referring to FIG. 9, when the mobile station 8 receives the setup message from the packet processor 48, step 400, the mobile station 8 displays the sender's identification, which is included in the header of the data packet, including the call group ID and the name of the individual user, step 402 . In response, the receiver can use the mobile station man-machine interface interaction method to receive the call, step 404. If the user does not receive, the mobile station does not respond to this setup message. Otherwise, the mobile station 8 sends an acknowledgment to the packet processor 48, and puts the call group ID in the current call record in the mobile station memory 28, steps 406 and 408.

One result of the job packet processor 48 receiving the confirmation is that any data packet subsequently transmitted by the voice data sender is transmitted to the receiving mobile station 8 by the packet processor 48 using the virtual connection, step 410. At the receiving mobile station 8, these data packets are converted into voice data and output as voice signals, step 412, until an end message is received from the packet processor 48, step 414.

When receiving the end message, the receiving mobile station provides a voice or image indication to the user, indicating the end of the voice data packet reception, step 416; it also indicates that the call group can now be caught by the receiver if desired.

In order to catch the call group after a call is established, any participant can press the PTT button 44 during a period of inactivity. This means that in the following cases: the original receiving mobile station receives the transmission end message, as in step 214, and before receiving another voice data packet from another participant; and the original sending mobile station is releasing After the PTT button and before receiving voice data packets from other participants.

Referring again to FIG. 7, when the mobile station 8 detects that the PTT button is pressed in this inactive state, the mobile station 8 sends a call catch request to the packet processor 48, step 216. The call group ID stored in the current call group ID record of the mobile station 8 is automatically included in the call catch request message by the mobile station. The user therefore does not need to identify the call group of the call it is currently participating in.

If within the time limit set in the mobile station 8, no call capture confirmation from the packet processor 48 is received; the mobile station 8 can try again by sending another call capture request at a later stage Catch this call.

If a call capture confirmation message is received from the packet processor 48, in step 218, a voice or visual indication will tell the user that it is successful, step 220; then the user can press and hold the PTT button and talk to the microphone 24 of the mobile station 8. The way of speaking transmits his voice to all the participants in the current call group.

Referring to Figure 10, when a call capture request is received, step 500, the packet processor 48 queries PUD52, step 502, in order to determine whether there are other participants in the call that have captured the call group, which means that In the call catch flag of field 64 of the call group record. If no call capture flag appears in the call group record, the packet processor 48 sends a call capture confirmation message to the sender of the call capture request, step 504, and adds a call capture flag to the reserved PUD. In the field 64 corresponding to the sender in the call group record, step 506.

Referring to FIG. 11, after receiving an end participation request from a user mobile station currently participating in a call, in step 600, the packet processor 48 deletes the call from the current call group field 70 stored in the end request sender record of the PUD 52 Group ID, step 602.

If only one participant remains in the call, step 604, the last reserved participant sends an end call message, step 606, the call group ID in the current call group field recorded by the last participant in PUD52 is delete. The impossible receiver record is also deleted from the call waiting table in the PUD, and the voice data corresponding to this call group stored in the packet memory 50 is also deleted.

Figure 12 illustrates a mobile station 700 related to another embodiment of the present invention. The mobile station 700 includes the elements shown in FIG. 2 of the method implemented in the mobile station. These elements are marked with the same reference numerals and have the same functions described in the mobile station 8.

The mobile station 700 therefore has a voice call for a GPRS virtual connection, as described in FIGS. 2 to 11, which is completed by the user operating the auxiliary keyboard 32 and the PTT button 34. In addition, the mobile station 700 can operate in a video conference mode.

The mobile station 700 includes a liquid crystal display (LCD) 702, and static and TV images can be displayed on the 8-character digital display 30 of the mobile station. In addition, the mobile station 700 includes a charge-coupled (CCD) camera 704, which can capture still and/or TV images; and an image data codec 706, which can follow known static and/or TV coding techniques, such as JPEG Or/and MPEG-4, encode and decode still and/or TV images.

The image data codec 706 is connected to the GPRS module 19, which allows image data to be grouped or split into groups and sent via the GPRS wireless interface.

The mobile station 700 interacts with the system described in FIG. 2, in particular the packet processor 48, using the same method described in FIGS. 6-11. Therefore, the packet processor can not only form a virtual sound data connection when two participants are calling or a group sending call, but also can form a virtual image data connection. The dynamic bandwidth allocation function provided by GPRS allows data transmission at a sufficient rate to transmit the television data captured by the television camera 704 via the GPRS wireless interface and encoded and decoded in the codec 706.

Referring to Figure 7, when the mobile station 700 is used in a video conference mode, the previously described process is used in the mobile station to establish and catch a TV call, and transmit the TV and audio data to the participants of one or more call groups in the PLMN . In connection with this, the step 208 originally described in FIG. 7 includes receiving the television data converted by the television camera 704 and the image codec 706, plus the sound obtained by the microphone 24 and converted by the sound codec 20 data. At this time, step 210 includes transmitting voice and television data in separate data packets or in the same data packet, while keeping the PTT button 34 activated. In connection with this, although it is called the "PTT" button, it is actually a "press to send sound and TV image" button.

In another way, the image data is accompanied by the sound data. In step 210, the still image data is captured in the camera 704 and encoded and decoded by the image data codec 706.

In another way, in step 210, the mobile station 700 is arranged to separately transmit image data, including television images and still image data.

A special method adopted by the mobile station 700 is selected by the user of the mobile station through a man-machine interface; for example, the auxiliary keyboard 32 performs interactive selection.

Referring to FIG. 8, the packet processor 48 can complete the process described above, and receive and respond to the call establishment request of the image and/or voice call. Related to this, in step 312, the packet processor may receive image data packets and/or voice data packets while a certain receiver is catching a call. The packet processor 48 processes packets transparently, regardless of the content of the received data packet.

Referring to Figure 9, mobile 700 can receive call setup messages, and this reception is the same for image and voice calls. Related to this, in step 410, the received data packet contains image and/or sound data packets via the GPRS wireless interface; in step 412, it is included in the image data codec and/or sound codec, and these data packets are converted And output the image and/or sound signal on the display 702 and/or on the loudspeaker 22.

Therefore, this embodiment of the present invention provides a method and device, using them, a half-duplex video conference call can be implemented between the two or between the call group participants in a sending manner. The advantage is that when the system user wants to transmit image data that requires a relatively high amount of bandwidth, the TV data is only transmitted in one direction at a time and only intermittently. In addition, the energy requirements of mobile stations are relatively low. This is in contrast to the usual concept of a video conference call, where the TV data is transmitted continuously and in full duplex mode.

It should be understood that various modified and equivalent methods can be applied to the above-mentioned embodiments without departing from the scope of the present invention.

The described implementation method of the mobile terminal 700 can run in two ways: the GPRS virtual connection method and the usual circuit switching method. Other embodiments of the present invention include that the mobile station can only operate in the GPRS virtual connection mode of the present invention.

The feature of the implementation of the two GPRS virtual connection modes of the present invention described above is half-duplex, where only the calling party can transmit voice and/or image data at a time. However, GPRS allows simultaneous transmission and reception of data packets via a wireless interface. Therefore, in the case of a call between two participants, the transmission of voice and/or image data can occur simultaneously to provide a full-duplex virtual connection. In this case, no participant "catch" the call group, and no party is prevented from sending voice and/or image data when receiving such data.

In the above embodiment, when a user accesses or leaves the GPRS service, the GGSN sends registration and deregistration messages to the packet processor 48. Other signaling procedures are possible. For example, when a call setup request is received, the packet processor 48 may request the HLR and/or GGSN 44 to determine the current status of potential call participants. The registration/deregistration message may also be sent by the HLR12 to the packet processor 48 instead of being sent from the GGSN44.

In the above description of the embodiment, the control message transmitted between the mobile station and the packet processor 48 includes the call group ID, and it is necessary to refer to the call group record. In the case of two participants calling, this call group ID can be replaced by a single recipient ID recorded by a single recipient in PUD52.

In the above, the packet data network 46 is regarded as an external packet data network. The fact that the packet data network 46 is "external" means that it is outside the scope of the GGSN 44, but it can belong to and be managed by a PLMN operator. Therefore, it can form part of an intranet or something similar. It is also possible to use a single physical connection between the GGSN 44 and the packet processor 48. The function of the packet processor 48 can be integrated with the GGSN44.

In the above description, the virtual connection is between mobile stations operating in the same PLMN controlled by the packet processor. As illustrated in FIG. 3, the GGSN 56 in another PLMN can also be accessed from the packet processor via the packet data network 46. Therefore, the packet processor can also be used to establish a virtual connection between a mobile station operating in this illustrated PLMN and a mobile station operating in another PLMN including GPRS facilities. In addition, the packet processor 48 may also control a virtual connection between a mobile station operating in the illustrated PLMN and a fixed terminal, such as the fixed terminal 58 connected to the packet data network 46 in FIG. 3.

In the above-mentioned embodiment, the period for catching the calling group and the mobile station to transmit voice and/or image data is determined by manually pressing the PTT button 36. The interaction of other man-machine interfaces can also be used to determine the period of call catching operation and the mobile terminal sending voice or image data. For example, those operations and periods can be activated by sound.

In the above embodiment, the packet memory 50 stores the data packets received during the virtual call connection for potential call participants. In addition, the packet memory 50 can also be used to store voice mail information and data information received via the GPRS service and to be sent out via the GPRS service. In addition, the packet memory 50 can store the required information sent to the user station via the GPRS service, such as stock price information, news and weather, etc., which can be in the form of text information, still image information, sound information and/or TV image information. Way to provide.

Implementations of mobile terminals that differ from the described mobile phones are possible. For example, the mobile terminal can be a car phone; it is composed of a GPRS-enabled hardware unit mounted on the car and a handheld microphone/push-to-talk (PPT) unit connected to a hardware unit via a soft cord plug.

The transmission of sound and image data in the half-duplex communication mode has been described above. The data packet transmitted between the user stations by the packet processor 48 can also form a text message (short message), which can be sent in the content of a call or sent in a separate call content. It is more desirable that the transmission of the text message is not restricted by the packet processor 48. The packet processor only serves to confirm the possible recipients of a text message to be transmitted and obtain the recipients address from PUD52. It is impossible for the recipient to receive it. The message is stored in the packet memory 50 at the time.

Here, reference is made to the GSM-type system. Such systems include a system based at least in part on GSM, which is specified in the GSM technical specifications published by the European Telecommunications Standards Institute (ETSI), such as the DCS1800 system, the PCS1900 system, and the third-generation system (such as Universal Mobile Communications). The system-UMTS) is based at least in part on GSM.

It appears that modifications and changes of the above-mentioned embodiments can be adopted without departing from the scope of the present invention, which will be specified in the appended claims.