HK1026558A - Method and arrangement for setting data transfer parameters in a data transfer system - Google Patents

Description

Method and device for setting data transmission parameters in a data transmission system

The invention relates to a method and a device for setting data transmission parameters in a data transmission system. The invention is preferably applied in a digital cellular system for changing the channel configuration during a connection.

In connection with the establishment of a data transmission connection in a digital cellular system, the connection parameters are usually set before the data transmission connection intended for the transmission of user information is established. In GSM (global system for mobile communications) systems, for example, such connection parameters are, in particular, codecs which specify the data transmission rate, parameters which encode and specify the voice, data and fax transmission functions. Codecs currently in use are HR (half rate), FR (full rate) and EFR (enhanced full rate) codecs. Where FR codecs may be selected for all devices connected to the system, according to the GSM system standard, HR and EFR codecs are optional in the device. The connection parameters of the data link contain, in particular, specifications regarding the bits and bytes to be transmitted. In the following, a previously known procedure for setting connection parameters in a GSM system is first described, after which the disadvantages associated with the prior art are described.

Before establishing a data transmission connection, a message for establishing a connection is transmitted from the mobile station to the data transmission system, which contains data about the capabilities of the data transmission equipment in the BC (bearer capacity) data area reserved for this purpose. When the mobile station transmits a message about the data transmission system, the data system checks the compatibility of the parameters contained in the message. Thereafter, the system transmits a reply message to the mobile station confirming receipt of the message to establish the connection and data regarding whether the proposed parameters are compatible. In the case of incompatibility of the parameters proposed, it is possible to agree on the parameters and to change certain parameters by sending new parameters in the response message.

In the BC data region, for example, it can be stated that the terminal is capable of data transmission at the HR and FR data transmission rates. The data transmission system then uses one of the data transmission rates involved during the connection. The data transmission rate may be changed during the connection, for example, when changing from one base station to another (handover). Then, for example, those base stations that can use the HR data transmission rate use it, while other base stations use the FR data transmission rate. Within the BC data framework used, changes to the codec then occur as controlled by the data transmission system. The change of the codec is realized by using a so-called ASSIGNMENT or HO (handover) procedure.

In addition, procedures for changing voice connections and data connections are previously known. In this case, the message for establishing the connection to be transmitted during connection establishment contains two BC data areas. Among these, the first data zone BC1 is used for the configuration of the voice connection, and the second data zone BC2 is used for the configuration of the data connection. During the connection, the configuration in use may change between the configurations BC1 and BC2, which are specified during the connection establishment. This change takes place by using the so-called ICM (incoming call modification) procedure.

For example, in publication [1] Mouly, Paute: the GSM System for Mobile communications 1992, ISBN 2-9507190-0-7, describes The GSM System in detail.

In the solutions according to the prior art described above, there are a number of disadvantages. First, a connection established as a normal voice connection cannot be converted to a data connection during the connection. If during a voice connection, for example, there is a need to send a fax, the voice connection must be disconnected and a new connection established, which is configured for fax transmission during the connection establishment phase. Although the need for several channel configurations is already known at connection set-up, in the solutions according to the prior art it is not possible to use more than two sets of connection parameters during the same connection. Thus, for example, during a voice/data connection, a fax cannot be sent. And a new connection must be established to accomplish this task.

Another disadvantage associated with the prior art is that the parameters of the data transfer connection must be known already at the time of connection establishment. For example, if the device configuration of the terminal can be changed, the parameters relating to the wrong device configuration can be selected at the connection setup, in which case the connection must be set up again in order to correct the parameters. Such a situation may occur in particular because when the connection is established, the peripheral devices attached to the terminal are not connected and the system reports this only after the connection has been established.

These problems occur in particular in the case where the appropriate data transmission parameters are not known at the time of connection set-up, but these parameters have to be found by means of an iterative method. During this procedure, a number of voice connections must be established for the trial parameters in conformity with one another, and a number of data connection attempts must be made for testing the conforming trial parameters.

In addition, it is difficult to use the solution according to the prior art for the following reasons, separate subscriber numbers are usually required for the voice data, data and fax functions and for their conversion functions.

As is apparent from the above-described examples, the procedure according to the prior art is multi-stage and awkward in many operating situations, so that the total time required for transmitting the necessary data can become unreasonably prolonged.

One concept of the invention is that the recommendation program sets connection parameters during a data connection. It is then possible to change the channel configuration of the connection if necessary, independently of the configuration selected at the time of connection establishment.

By means of the invention, there are a number of advantages compared to the prior art. By means of the solution according to the invention, data transmission connections can be established by first setting connection parameters, for example relating to voice connections, and during voice connections, the connection parameters can be changed if necessary to make them suitable for data transmission. Thus, at call set-up, neither information about whether a data connection is likely to be used for data and or fax transmission, nor information about the parameters to be used in such transmission is required. During a voice connection it is also possible to find out the role of the different transmission parameters in respect of the terminal being used. Furthermore, it is an advantage of the present invention that separate subscriber numbers (multiple number scheme) required for voice, fax and data transmission functions and for their transfer functions can be replaced by a single subscriber number (single number scheme). Thus, the present invention makes a single number scheme a viable solution.

The method according to the invention for setting data transfer connection parameters in a data transfer system is characterized in that,

connection parameters to be used in the data transmission connection are selected after the data transmission connection is established,

-data relating to the selected connection parameters is transferred between the terminal and the data transmission system, and

-the connection parameters used by the data transfer connection are changed to be compatible with the transfer connection parameters.

The data transmission system according to the invention comprises means for transmitting first connection parameters between said data transmission system and a terminal connected to the system, and means for establishing a data transmission connection of a transaction channel on the basis of said first connection parameters, characterized in that it comprises means for transmitting second connection parameters between said data transmission system and said terminal during said data transmission connection, and means for changing the connection parameters used in said data transmission connection on the basis of said second data transmission parameters.

The terminal according to the invention comprises means for transmitting first data transmission parameters between the terminal and the data transmission system, and means for establishing a data transmission connection to the data transmission system on the basis of said first data transmission parameters, characterized in that the terminal comprises means for transmitting second data parameters between the terminal and the data transmission system during said data transmission connection, and means for changing the connection parameters used in said data transmission connection on the basis of said second data transmission parameters.

Preferred embodiments of the invention are given in the dependent claims.

The invention is described in more detail below by means of the attached drawings, in which

Fig. 1 shows a flow chart of a method for setting connection parameters according to the invention, and

fig. 2 shows a block diagram of a mobile station according to the invention and its connection to a cellular system according to the invention.

Fig. 1 shows a flow chart of a method for setting connection parameters 100 according to the invention. Before the connection is established, the first connection parameters BC1 are selected, stage 101. Thereafter, a message for setting up the connection is formed at the terminal, which message contains a record for the transmission of the connection parameters BC1, phase 102. The formed connection message is then transmitted to the data transmission system, stage 103. After receiving the connection message, the data transmission system forms a reply message and sends it to the terminal, stage 104. Thereafter, a data transmission connection is established by using the channel configuration according to the selected connection parameter BC1, phase 105.

When the connection has been established, the channel configuration specified at the connection establishment is used until the connection has to be ended, stage 106, 107, or until it is desired to change the connection parameters, stage 110. When it is desired to change the channel configuration, a new connection parameter BC2 is selected, stage 111. Thereafter, a MODIFY message is formed containing data of the new connection parameters and the MODIFY message is transmitted from the terminal to the data transmission system, stage 112. After receiving the MODIFY message, the data transmission system verifies the compatibility of the proposed parameters and changes the channel configuration of the connection so as to be compatible with the new connection parameters, stage 113. Thereafter the data transmission system sends a response message MODIFY COMPLETE to the terminal, which message contains an acknowledgement about the new channel configuration, stage 114, after which it returns to stage 106. If the data transmission system does not support the channel configuration proposed in the MODIFY message, it sends a MODIFY reject message to declare that the connection parameters cannot be changed in the proposed way. The MODIFY REJECT message contains the connection parameters that were valid before the transmission of the MODIFY message.

The above-described change of the connection parameters may be performed several times during the connection. A new MODIFY message is also transmitted if it is desired to return to the channel configuration used earlier during the connection.

In the above, the transmission of the connection parameters in the message according to the ICM procedure of the GSM system has been described. Within the framework of the invention, however, other procedures for message transmission for transmitting new connection parameters can also be proposed for the GSM system.

In the above, the procedure for transmitting a message in the case where a change of connection parameters is initiated from a mobile station has been described. The connection parameters may naturally change so that they are also initiated by the data transmission system, in which case the data transmission system sends a MODIFY message to the terminal containing the selected new connection parameters. Thereafter, the terminal sends a response message MODIFY COMPLETE to the data transmission system, which, after receiving the message, readjusts the connection parameters to the new parameters selected. If the terminal does not accept the proposed connection parameters, it sends a MODIFY REJECT message containing valid connection parameters to the data transmission system. The data transmission system leaves the connection parameters unchanged after receiving this message.

Fig. 2 shows a simplified block diagram of a mobile station 200 according to the present invention. In fig. 2, only the essential parts of a mobile station are shown, in which the application of the invention is considered. The mobile station comprises an antenna 201 for receiving radio frequency signals, i.e. RF signals, transmitted by the base station. The received RF signal is controlled, for example, by a duplex filter 202 connected to an RF receiver 211, where the signal is amplified and converted to digital form. Thereafter, the signal is detected and demodulated, block 212, and decoded according to the connection parameters in block 213.

If the connection is specified as a voice connection, then voice signal processing is performed on the received signal, where the signal is also converted to sound, block 230. If the connection is specified as a fax or data connection, the decoded data can be transmitted to an external data processing device via an interface in the mobile station. Alternatively, the received data may be processed in the mobile station, for example by storing the data in memory 204 and displaying it on display 232. Messages received from the data transmission system may be stored in memory 204 and, when necessary, displayed on display 232. The processing operation of the above-mentioned data transmission is controlled by the control unit 203. The control unit also performs message formation and interpretation in accordance with the present invention.

For transmitting speech there is a processing block in the mobile station for the speech signal 233, which converts the sound signal into a digital electrical signal. If the information to be transmitted is data, it may be read out from the memory 204 or received from an external data processing apparatus through an external interface. Thereafter, the data to be transmitted is encoded in accordance with the selected connection parameters in block 221. From the encoded data, a burst is formed, block 222, which is modulated into an RF signal to be transmitted in block 223. The RF signal to be transmitted is transmitted to the antenna 201, for example, through the duplex filter 202. In addition, the above-mentioned data processing and transmitting functions are controlled by the control unit 203.

The blocks of the mobile station according to the invention can be constructed by means of components known per se. However, the control unit controlling the other blocks performs control functions for these blocks according to various different software, thereby obtaining the functions of the blocks according to the present invention described above.

Fig. 2 additionally shows cellular system components used in connection establishment and data transmission. The RF signal is transmitted and received through an antenna 250 of the base station 251. A data transmission connection is established from the base station 251 through the base station controller 252 to the switching centre 253. The switching centre 253 is additionally linked to other base stations of the system, for example to the public switched telephone network PSTN. The other party of the data transmission connection may access the data transmission system via a base station, such as the mobile station 200, or alternatively via the fixed telephone network PSTN.

The function according to the invention is performed in the base station of the cellular system by means of similar devices as in the mobile station.

Only certain embodiments of the invention have been described above. The principle according to the invention may naturally be modified within the framework of the scope defined by the claims, by modifying the scope of use and the implementation details.

In particular, the GSM data transmission system has been described only as an example, and the application of the invention is not in any way restricted thereto. The invention can preferably be used in particular in GSM, PCN, DCS, UMTS or FPLMTS cellular systems. The invention can be applied to fixed data transmission systems, such as ISDN and B-ISDN systems, in addition to mobile station systems.

Claims (10)

1. Method for setting data transfer connection parameters in a data transfer system, characterized in that,

connection parameters to be used in the data transmission connection are selected (111) after the data transmission connection is established,

-data of the selected connection parameters are transferred (112) between the terminal and the data transmission system, and

-the connection parameters used by the data transfer connection are changed to be compatible with the transferred data transfer connection parameters (113).

2. Method according to claim 1, characterized in that the data transmission parameters for the voice connection are selected and set (101) before the data transmission connection is established and the data transmission parameters for the data connection and/or the fax connection are selected and set (111) after the voice connection is established.

3. A method according to claim 1 or 2, characterized in that during the data transmission connection at least three sets of connection parameters are used.

4. Data transmission system comprising means (103) for transmitting first connection parameters between said data transmission system and a terminal connected to the system, and means (105) for establishing a data transmission connection on a transaction channel on the basis of said first connection parameters, characterized in that it comprises means (112) for transmitting second connection parameters between said data transmission system and said terminal during said data transmission connection, and means (113) for changing the connection parameters used in said data transmission connection on the basis of said second data transmission parameters.

5. A data transmission system according to claim 4, characterized in that it comprises means (105) for establishing a voice connection and means (112) for transmitting connection parameters between the terminal and the data transmission system for changing the connection to a data and/or fax connection (113) compatible with the transmitted connection parameters.

6. Terminal comprising means for transmitting first data transmission parameters between the terminal and a data transmission system, and means for establishing a data transmission connection to the data transmission system based on said first data transmission parameters, characterized in that the terminal comprises means (201) for transmitting second data parameters between the terminal and the data transmission system during said data transmission connection (223), and means (203, 213, 221) for changing connection parameters used in said data transmission connection based on said second data transmission parameters.

7. Terminal according to claim 6, characterized in that it comprises means (201) for establishing a voice connection to the data transmission system (223), means (201) for transmitting connection parameters between said terminal and the data transmission system (223), and means for changing the connection to a data and/or fax connection (203, 213, 221) compatible with the transmitted connection parameters.

8. A method according to any of claims 1-3, a data transmission system according to any of claims 4-5, a terminal according to any of claims 6-7, characterized in that said data transmission system is substantially a GSM system.

9. A method, data transmission system, or terminal according to claim 8, characterized in that the data of the new connection parameters is included in a MODIFY message transmitted between the terminal and the data transmission system.

10. A method according to any of claims 1-3, a data transmission system according to any of claims 4-5, a terminal according to any of claims 6-7, characterized in that said data transmission system is a GSM, PCN, DCS, UMTS, FPLMTS, ISDN, or B-ISDN system.