Method of transmitting service information, and radio system

The present invention relates to a wireless system for transmitting packet traffic and a method for transmitting service information in a wireless system for transmitting packet traffic.

One drawback of this wireless system and the wireless systems being developed is the limited amount of wireless resources available. The number of radio frequencies is limited and divided among several systems and operators. Various solutions have been devised to solve this problem.

Conventional wireless systems for general use are based on circuit switching technology. In the system realized by this technology, a channel is reserved for the connection between devices. This channel is available to the device for the duration of the connection, with or without continuous traffic on the channel. This solution is sufficient mainly in systems that transmit audio. With the need for telecommunications technology growth, transmission connections will be increasingly used for data transfer. The traffic carried over the data connection is often very bursty. That is, a large amount of data is transferred, which sometimes requires high-speed transfer processing power, and sometimes there is almost no traffic on the channel. For such connections, packet-switched connections are a very practical solution for capacity utilization. In packet-switched connections, channels are not reserved for terminals throughout the connection time, but only when data transfer is needed. Various wireless systems have been developed that utilize packet-switched traffic in which at least some of the terminal-to-terminal connections are made using the packet protocol. Examples of such systems are GPRS (General Packet Radio System) and an improved version of it, EGPRS (Enhanced General Packet Radio System).

Since the needs of data services and data transfer capacities are different from each other, each system is provided with the ability to establish a connection with different capacities. For a standard data connection, for example, the terminal is connected to the data network via the Internet. The system has a session management arrangement that defines the connection setup process. The data connection required between the terminal and the network in the system is established during the connection setup process.

Wireless systems are used for a variety of purposes, but their use has increased significantly over the past few years, and a number of services have been developed for that purpose, and this trend is expected to continue. Most new services do not require more connection between the terminal and the system. One of the reasons for this is that the amount of information to be transferred is small, and the connection between the network unit and the terminal required for the service requires short-term data transfer instead of continuous data transfer. ..

In existing systems that utilize packet traffic, a connection is always established between the network part of the system and the terminal through a session management arrangement, and only the quality and capacity of the connection change according to the request. Therefore, this method is not flexible and wastes transfer capacity.

<p> An object of the present invention is to provide a wireless system and a method that enable flexible transfer of service information in a system without wasting capacity.</p>

<p> This object is achieved by the method of the present invention, i.e., when the connection between the terminal and the network that transfers packet traffic is established, achieved by the method of transmitting service information between the network part of the wireless system and the terminal. The session management arrangement runs the connection setup process. When the service information is transmitted between the terminal and the network unit by the method of the present invention, the side requiring the service starts the connection setup process. During startup, the service-requiring party will message the need for service information and quality of service. The service provider responds with one or more messages containing service information. The connection setup process ends before establishing a connection.</p><p> The present invention also relates to wireless systems that carry packet traffic, and when terminals and network units are connected, they initiate a connection setup process through a session management arrangement. In the system of the present invention, the service-requiring party is configured to initiate a connection setup process when the service information needs to be transmitted, forwarding the service information and the quality of service request in a message. The service provider is configured to respond with one or more messages containing service information, and the connection setup process terminates before establishing a connection.</p>

<p> The methods and systems of the present invention have several advantages. A single connection setup process can be used for both establishing an actual data connection and for service transmission that does not require an actual data connection. Since no connection needs to be established for each service, resource management becomes more flexible and resources are not wasted. Thanks to the flexibility of the connection setup process, new services can be easily introduced into the system. The present invention will be described in detail below with reference to preferred embodiments based on the accompanying drawings.</p>

<figref num="1">FIG. 1 shows a telecommunications system to which the present invention applies.</figref><figref num="2">Figure 2 shows the configuration of another mobile communication system used as an example.</figref><figref num="3">FIG. 3 shows in more detail the configuration of the mobile communication system used as an example.</figref><figref num="4">FIG. 4 shows the structure of the transmitter / receiver used in the system according to the present invention.</figref><figref num="5">Figure 5 shows some protocol stacks in a cellular wireless network.</figref><figref num="6">FIG. 6 shows a preferred embodiment of the present invention.</figref>

The present invention applies to various wireless systems that forward packet traffic, with terminals having different wireless path properties. This is irrelevant to which multiple access method the system employs. For example, CDMA, WCDMA, and TDMA can be used as multiple access methods. In addition, the system supports both circuit-switched and packet-switched connections. FIG. 1 shows a digital data transfer system using the solution according to the invention. This is part of a cellular radio system consisting of base stations 200 having bidirectional connections 202-206 with subscriber terminals 208-212. The base station is further connected to base station controller 214, transferring terminal connections to another part of the network. In the example of FIG. 2, the connection includes circuit-switched and packet-switched connections.

The configuration of the mobile communication system using the preferred embodiment of the present invention will be described below with reference to FIG. The main parts of the mobile communication system are the core network CN, the terrestrial wireless connection network BSS, and the subscriber terminal MS. In this example, the interface between CN and BSS is called the Gb interface, and the interface between BSS and MS is called the Um interface.

The wireless connection network is composed of the base station subsystem BSS. Each base station subsystem BSS is composed of a base station controller BSC and one or more base transmission / reception station BTS having a transmitter / receiver. The interface between the base station controller BSC and the base transmitter / receiver BTS is not standardized. The coverage of the base station, or cell, is represented by C in FIG.

Figure 2 is rather abstract, as the cell-based radio system is illustrated in Figure 3 by a more detailed example. Although Figure 3 contains only the most basic block diagrams, it is clear to those skilled in the art that traditional cellular wireless networks have other features and configurations that do not need to be described in more detail. It should be noted that Figure 3 shows only one viable configuration. In the system according to the invention, the details may differ from those shown in FIG. 2, but such differences are irrelevant to the present invention.

A cellular wireless network generally consists of a fixed network infrastructure, namely a network unit 400, and a fixed, vehicle-mounted, or portable subscriber terminal 402. The network unit 400 has a base station 404. The base station corresponds to node B in the previous figure. Several base station 404s are centrally controlled by base station controller 406, which communicates with base station 404. The base station 404 has a transmitter / receiver 408 and a multiplex control device 412.

The base station 404 further includes a control device 410 that controls the functions of the transmission / reception device 408 and the multiplex control device 412. The multiplex controller 412 is used to configure the traffic on one forwarding connection 414 and the control channels used by several transmitters and receivers 408. The transfer connection 414 forms an interface called lub.

The transmission / reception device 408 of the base station 404 is connected to the antenna device 418, and a bidirectional wireless connection 416 with the subscriber terminal 402 is established. The structure of the frame transferred over the bidirectional wireless connection 416 is called the wireless interface Um in the system specifications.

Base station controller 406 has a group switching field 420 and controller 422. The group switching field 420 is used for voice and data switching and signal line connections. The wireless network subsystem 432 formed by the base station 404 and the wireless network controller 406 also includes a transcoder 424. The transcoder 424 is typically located as close as possible to the mobile service exchange center 428 to save transfer capacity when voice is transferred in a cellular wireless network format between the transcoder 424 and the wireless network controller 406.

Transcoder 424 converts the different digital voice coding formats used between public and wireless telephone networks into compatible formats, such as from fixed network formats to cellular wireless network formats, and vice versa. .. The control device 422 is in charge of call control, movement management, statistics and signal aggregation.

FIG. 3 shows the mobile service exchange center 428 and the gateway mobile service exchange center 430, which controls the external connection of the mobile communication system, for the connection with the public telephone network 436.

As shown in FIG. 3, the group switching field 420 can establish a connection to both the public switched telephone network (PSTN) 436 and the packet forwarding network 442 via the mobile service exchange center 428.

The connection between the packet forwarding network 442 and the group switching field 420 is established by the support node 440 (SGSN = Serving GPRS Support Node). The function of the support node 440 is to transfer packets between the base station system and the gateway node (GGSN = Gateway GPRS Support Node) 444 and keep a record of the location of the subscriber terminal 402 in the area.

The gateway node 444 connects to the public packet forwarding network 446 and the packet forwarding network 442, and the Internet protocol or the X.25 protocol can be used for the interface. Gateway node 444 hides from public packet forwarding network 446 by encapsulating the internal configuration of packet forwarding network 442. Therefore, the public packet forwarding network 446 considers the packet forwarding network 442 to be a subnetwork having a subscriber terminal 402 to which the public packet forwarding sends and receives packets.

The packet transfer network 442 is generally a private network and utilizes the Internet Protocol to signal and tunnel user data to carry packets. The configuration of packet forwarding network 442 can vary depending on the architectural operator and the lower layer protocols of the Internet Protocol.

The public packet forwarding network 446 may be, for example, a global internet network, where a terminal 448, such as a server computer, is present and connected to the internet to which packets are to be forwarded to the subscriber terminal 402.

The time zone not involved in circuit-switched transfer is generally used for packet transfer of wireless interface 416. When capacity is dynamically reserved for packet transfer, i.e., when a data transfer request is received, any free channel is allocated for packet transfer. This process is flexible, meaning that circuit-switched connections take precedence over packet-forwarded connections. If necessary, circuit-switched transfer takes precedence over packet-switched transfer, i.e., the time frame used for packet-switched transfer is assigned to circuit-switched transfer. This can be done so that packet-switched transfers can well tolerate such communication interruptions. The transfer will continue using a separately assigned time frame. This process does not give absolute priority to circuit-switched forwarding, but is performed so that both circuit-switched and packet-switched forwarding requests arrive in the order in which they arrive. Such processing, however, is irrelevant to the present invention.

FIG. 4 shows a more detailed structure of the transmitter / receiver 408. The receiver 500 has a filter that blocks frequencies outside the desired frequency band. After this, the signal is converted to an intermediate frequency or directly to baseband, and the signal is extracted and quantized by the analog / digital converter 502. The equalizer 504 compensates for interference, for example, interference caused by multipath transmission. The demodulator 506 picks up the bit flow from the equalized signal and transfers it to the demultiplexer 508. The demultiplexer 508 separates the bit flows of different time slots into separate logical channels. The channel codec 516 decodes the bitflow of each logical channel, that is, does the entire bitflow contain signal information transferred to controller 514 or audio sent to transcoder 424 of base station 406? To judge. Channel codec 516 also corrects the error. The control device 514 controls each device to execute an internal control task. The burst generator 528 adds a training sequence and tail bits to the data received from the channel codec 516. The multiplex controller 526 indicates the time slot for each burst. The modulator 524 modulates the digital signal into a radio frequency carrier. This feature is analog, so you need a digital-to-analog converter 522 to do it. Transmitter 520 has a bandwidth limiting filter to control the transfer output. The synthesizer 512 provides each device with the required frequency. The clock of the synthesizer 512 can be controlled locally or centrally, for example from the base station controller 506. The synthesizer 512 uses, for example, a voltage controlled oscillator to generate the required frequency.

As shown in FIG. 4, the configuration of the transmitter / receiver is further divided into a radio frequency unit 530 and a digital signal processing device 532 having software. The radio frequency unit 530 has a receiver 500, a transmitter 520, and a synthesizer 512, and the digital signal processor and its software 532 include an equalizer 504, a demodulator 506, a multiplex separator 508, a channel codec 516, and a controller 514. It has a burst generator 528, a multiplex controller 526, and a modulator 524. The digital / analog converter 502 converts an analog radio signal into a digital radio signal, and the digital / analog converter 522 converts the digital signal into an analog signal.

The configuration of the subscriber terminal 402 is described using the explanatory diagram of the transmitter / receiver 408 shown in FIG. The components of the subscriber terminal 402 have the same functions as the components of the transmitter / receiver 408 described above. In addition, the subscriber terminal may have a bidirectional filter between the antenna 418, the transmitter 500 and the transmitter 502, a user interface unit and a voice codec. The voice codec connects to the channel codec 516 via path 540. The functions according to the preferred embodiments of the present invention are generally performed in the terminal by software, that is, including software having the necessary commands in the control device of the terminal.

Although Figure 5 shows the EGPRS control plane protocol stack, it should be noted that the examples are not limited to EGPRS alone. The protocol stack is the OSI reference model (Open systems) of the ISO (International Organization for Standardization). It is formed by Interconnection (Open Systems Interconnection). In the OSI model, the protocol stack is divided into layers, which are, in principle, seven layers. Figure 5 shows which protocol section is being processed at each network element. The network elements shown in the figure are the subscriber terminal MS, the base station system BSS, the support node SGSN, and the gateway node GGSN. The base station and the base station controller are not shown separately because they do not define an interface between them. In principle, the protocol processing defined by the base station system BSS can be freely separated between the base station 404 and the base station controller 406, but in reality, the transcoder 424 also belongs to the base station system BSS. Nevertheless, it is not split with the transcoder 424. Each network element is separated by interfaces Um, Gb, Gn between base station 404 and base station controller 406.

The layers in each of the MS, BSS, SGSN, and GGSN devices logically communicate with the layers of other devices. Only the lowest physical layer communicates directly with each other. Since the other layers utilize the services provided by the next lower layer, the message physically travels vertically between the layers, and only at the bottom layer the message travels horizontally between the layers.

Actual bit-level data is always transferred using the first layer RF, L1, which is the physical layer. The mechanical, electrical, and functional attributes required to connect to the physical transfer path are defined in this physical layer. The second layer, that is, the data link layer, reliably transmits data by using the service of the physical layer. For example, fix a transmission error. In the wireless interface 416, the data link layer is divided into a sub-layer RLC / MAC and a sub-layer LLC. The third layer, the network layer, provides an upper layer independent of data transmission and switching technology and is used to establish connections between devices. The network layer serves, for example, to establish, maintain, and release connections. In GSM, the network layer is also called the signaling layer, and has two main functions: it routes messages and makes multiple independent connections between the two elements at the same time.

The network layer consists of the session management sublayer SM and the GPRS mobile management GMM sublayer.

The GPRS Mobile Management GMM sub-layer handles results that result from the fact that subscriber terminal users move and are not directly related to wireless resource management. In a fixed network, this sublayer checks the user's privileges and connects this user to the network. Therefore, the cellular wireless network supports the movement and registration of users and the management of movement data. This sub-layer also checks the recognition of subscriber terminals and the recognition of authorized services. In this sublayer, message transmission is performed between the subscriber terminal MS and the support node SGSN.

The session management sub-layer SM manages all functions related to the management of packet-switched calls, but does not detect user movement. The session management sub-layer SM establishes, maintains, and releases connections. There are separate procedures for outgoing calls from the subscriber terminal and incoming calls to the subscriber terminal. In this sublayer, message transmission is performed between the subscriber terminal MS and the support node SGSN.

In the base station system BSS, the messages of the session management sub-layer SM and the mobile management sub-layer GMM are processed transparently, that is, they are only transferred back and forth.

In the network section, the functions according to the preferred embodiments of the present invention are conveniently performed by software. The software containing the required commands is inserted into the support node (SGSN).

In the solution according to the preferred embodiment of the present invention, two types of procedures that require their own parameters, general procedures common to all services and service-specific procedures are defined for the session management arrangement. ..

Examples of general procedures are service requests and responses to service requests. Two messages are defined for this procedure, namely "SM SERVICE REQUEST and SM SERVICE RESPONSE". These preferably have the following form: SM SERVICE REQUEST: {paramaters common to services, service-specific parameters} SM SERVICE RESPONSE: {paramaters common to services, service-specific parameters}

Therefore, the message contains a parameter block that is common to all services and a parameter block that is specific to the service.

An example of a service-specific procedure is a notification method, which is required for location-based services of terminals, for example. The notification method is used, for example, in the positioning process of a GSM system, and the corresponding procedure also applies to connections using this solution. The notification method is described, for example, in GSM 03.71: Location Services (LCS); Functional Description-Paragraph 7.6.1, Stage 2. Two messages, the location notification execution and the location notification return result, are described individually. In a solution according to a preferred embodiment of the invention, the logical state defines session management for coordinating the transmission of service information. The state defines the terminal and the network part separately. The following states define the terminal.

NON-PDP-INACTIVE-no service transmission in this state NON-PDP-INACTIVE-PENDING-the terminal has activated transmission of service information NON-PDP-INACTIVE-PENDING-the terminal has activated termination of service information transmission NON-PDP-ACTIVE-ongoing transmission of service information

The corresponding states that define the network part are as follows. NON-PDP-INACTIVE-no service transmission in this state NON-PDP-INACTIVE-PENDING-the network part has activated transmission of service information NON-PDP-INACTIVE-PENDING-the network part has activated termination of service information transmission NON-PDP-ACTIVE-ongoing transmission of service information NPN-PDP-MODIFY-PENDING-the network part has requested a change in the transmission of service information

Hereinafter, a solution according to a preferred embodiment of the present invention will be described with reference to the flow chart shown in FIG. As an example, it is assumed that the terminal needs a service and the service is provided by the network part. The terminal, that is, the side requiring the service, sends a message from the connection setup process to the network unit. The message indicates the need for service information and quality of service.

The service in question is location-based services, that is, terminals request location-based services from the network on the spot. Here, GPRS (General Packet Radio System) is used as an example, but the present invention is not limited to this.

The process starts at block 600. In block 602, the subscriber terminal sends a request message "SM SERVICE REQUEST" requesting location-based services to the wireless network, in this example via the base station system BSS, to the core network, in this example the support node SGSN. Send to. Desirably, prior art security procedures, such as authentication of the subscriber terminal, are subsequently performed. For clarity, such security procedures are not shown here.

Then, at least one function of the location-based service requested in the message is performed by block 604. The request message is related to the following location information service functions. That is, the measurement of the position of the subscriber terminal, the transmission of the location information auxiliary data to the subscriber terminal, and the transmission of the encryption key for decrypting the location information auxiliary data to the subscriber terminal. Such details are irrelevant here and will not be discussed in more detail.

When the desired function is performed, in step 606, the core network SGSN sends a response message "SM SERVICE RESPONSE" to the subscriber terminal over the wireless network in response to the request message, and the method ends at block 608. .. In this example, the response message may contain at least one of the following information: That is, the location information of the subscriber terminal, the location information auxiliary data, the encryption key for decrypting the location information auxiliary data, and the error code. The request message and the response message are the messages of the protocol layer corresponding to the third layer of the OSI reference model.

Although the present invention has been described with reference to an example based on the accompanying drawings, it is clear that the present invention is not limited thereto, and various modifications are made within the scope of the concept of the invention disclosed in the additional claims. Is possible.