Method and telecommunication system for transmitting a message

The invention relates to a method for transmitting a Message from a first telecommunications terminal to a second telecommunication terminal according to the preamble of claim 1 and a telecommunication system for Transmitting a message from a first telecommunications terminal to a second telecommunications terminal according to the preamble of claim. 2

In operating according to the GSM standard mobile networks has besides - of course dominating by far - voice communication, especially with regard to significant cost advantages, communication by means of short text messages (Short Messages) on the basis of this established standards successfully established. In addition to the cost benefits has the message transmission via SMS (Short Message Service) in certain applications also use value advantages. So are receiving and sending an SMS without acoustic harassment realized for the environment, and the transmission of Short message from those of the voice communication also additional expression and psychological accentuation.

When SMS is a point-to-point short message service, in response to the GSM protocol architecture on the Signaling plane is realized. It includes transportation packet-oriented useful data from and to mobile stations. The short messages are always a short message service center (SM SC = Short Message Service Center) in the store-and-forward operation transported. The service center accepts the maximum of 160 characters long SMS messages from a mobile station as opposed telecommunication terminal and forwards it to a second telecommunication terminal - a further mobile station or else a fax or other -.. on.

For the realization of this service defined the GSM standard a special protocol architecture. This is in the ETSI specifications set and is sufficiently described in the literature described (see for example J. Eberspächer, HJ birds.: "GSM Global System for Mobile communication", Stuttgart, 1997), so that a more detailed description herein superfluous is and refer to the appended list of standards / documents can be.

In the existing public line-connected telephone networks is such a transmission of short messages between normal telecommunication terminals (eg. as telephones) not currently possible.

From GB 2,298,339 A is a method for transmitting Short messages between a Short Message Service Center and a DECT cordless telephone consisting of a base station and a handset is known in which the short message from the service center to the base station via a separate, Service center operator-specific connection, for example, as an X.25 network is implemented, according to an SMS-specific Protocol is transmitted.

From US 5,815,506 is a satellite communication system known about a short message from a fixed network subscriber have been generated, in accordance with an SMS-specific Protocol is transmitted to a mobile subscriber. The short message is so, first of the fixed network subscriber via a PSTN-network to a short message server transfer. From there, the short message passes through a local Satellite ground station, a satellite and a mobile radio station for mobile subscribers. For the short message transmission between the fixed network subscriber and the mobile subscriber is a signaling outside the voice or Nutzdatenbandes, called the outer band signaling, used. In this type of short message transmission Messages can be amounts of up to a maximum of 16 Kbytes transferred. In the PSTN network are the transmission of this type a "dial up" modem and a DTMF tone detection available.

The invention is therefore based on the object, a method and to provide a telecommunication system, the transmission of the short messages to the SMS model in a wireline telephone network (landline) possible.

This object is proceeding with regard to their method aspect of the defined in the preamble of claim 1 The method by which in the characterizing part of claim 1 stated features and terms of their arrangement aspect starting from the in the preamble of claim 2 defined telecommunications system by those specified in the characterizing part of claim 2 resolved features.

The invention includes the fundamental idea without In view of the profound system differences between Mobile networks on the one hand and the known wireline Networks (fixed networks) on the other hand the proven SMS protocol architecture of the GSM standard (or even a comparable Architecture of the UMTS standard) on the fixed network to a certain extent reflect and expand.

defined with the specifications described below the invention, the transmission protocol and the physical and administrative conditions for the transmission of Short messages in the short message (SMS) format between the Terminal and the short message service center. The transmission protocol is preferred here to closely following the protocol defined in the GSM standard set. I hereby the aim is the transmission of short messages as for the fixed network new service with little effort and high compatibility with existing systems offer. There is a uniform SMS format in the GSM network and used in the fixed network, whereby the smooth transmission constructed of short messages between a according to the GSM standard, and operated mobile network and the invention equipped landline is ensured. also offers the chosen with this embodiment of the invention way the considerable practical advantage that the specification the SMS service largely recognized and the resorted meanwhile tried and tested GSM specifications can be.

In the physical layer, the data transmission is carried out between terminal and service center using DTMF signaling and / or an after ETS 300659-1 and ETS 300659-2 specified FSK (Frequency Shift Keying - Frequenzumtastkodierung) Off-hook signaling in the voice band (in-band signaling). This said transmission method can in any combinations are used. Specifically, make the terminal a signaling via DTMF and the service center can utilize FSK modulation, of course, each receiving unit for application Procedures must be adapted.

Above the physical layer is a Data Link layer (Data Link Layer) specifies the logical to Connection setup and the fitting to the default GSM SMS guaranteed. The latter standard is particularly in the ETSI documents GSM04.07 (ETS 300 556), and GSM04.11 GSM03.40 defined. In compatibility to this, the Data Link Layer free to adapt to the specific requirements To be defined.

According to an advantageous embodiment of the invention, the newly defined physical layer and movement of such data binding layer with the existing layers (layers) of the GSM-SMS protocol set combined. This is the Short Message Transfer layer (Short Message Transfer Layer = SM-TL) in accordance with ETSI document GSM03.40 and the connection management layer (Connection Management Layer = CM) to GSM04.11.

It is also possible that the combination of the newly defined physical layer and data link layer with the existing layers of the GSM-SMS protocol set the Short Message Relay layer (Short Message Relay Layer = SM-RL) comprises according GSM03.40 and 04:11.

In the connection management layer CM specifically defines an additional Message for signaling the connection state (CP-Connect) defines a format according GSM04.07 / Chapter 11 is determined. A special setting there are also in terms of the format of a message in the Data Link Layer DL. This will be discussed in more detail below.

In a preferred application of the invention, as further already indicated above, one of the telecommunication terminals a, for example, according to the GSM or else the future UMTS standard operated, connected wireless network, wherein the Connection between two networks in the usual way by a Gateway mobile switching center is prepared.

A further advantageous application of the invention results when at least one of the telecommunication terminals a cordless telephone is, of which or to which the short message via a, for example according to the DECT standard operated, Fixed station or PBX in or out of the landline Gets transferred. Modern cordless phones feature the main hardware requirements for implementation the proposed service; in particular they are typically with a suitable display unit and means for DTMF signaling and equipped to identify the top mentioned FSK off-hook signaling in the voice band formed.

Additional features and advantages of the invention result in based moreover from the following detailed description of the figures. Of which:<sl><li>FIG. 1 is a schematic diagram of a telecommunication system according to the invention,</li><li>Fig. 2 illustrates the layer model (model SI) of Configuration of FIG. 1,</li><li>Fig. 3 is a flow diagram for a telecommunications terminal from initiated call setup according to one embodiment the invention,</li><li>Fig. 4 is a flow chart for a of the short message service center initiated call setup according to one embodiment the invention,</li><li>Fig. 5 is a view showing the structure of a message for the Start the procedure on the connection management layer and</li><li>Fig. 6 is an illustration of the message format to the data link layer.</li></sl>

Fig. 1 shows schematically the basic components of a telecommunication system according to the invention, namely a public wireline telephone network (landline) PSTN, a device connected to this telecommunication terminal CD and also connected to the fixed network short message service center SM SC. On the interaction of these components relate the following explanations for explaining the invention.

Fig. 2 shows the associated SI-layers model, above the (Not shown here) physical layer. The Layer structure comprises first a - in more detail below specified - data link layer DL (Data Link Layer) and continue the process known from the GSM-SMS standard Layers connection manager CM (Connection Manager), short message relay layer SM-RL (SM Relay Layer) and short message transfer layer SM-TL (SM Transfer Layer) and - on The terminal side - Application (Application).

The protocol descriptions of the layers SM-TL, SM-RL and CM are the ETSI documents GSM03.40 [1] and GSM04.11 [3] remove; , see the enclosed standards / documents.

The basic requirement for transmitting short messages (Short Messages) via the fixed network PSTN is a circuit switching the units involved (telecommunications terminal equipment and short message service center). It is then immaterial whether the units via ISDN or an analog Interface are connected.

In the figures 3 and 4 schematically shows the establishment of a connection starting from a telecommunication terminal (Fig. 3) or, starting from the short message service center (Fig. 4). These graphs are for the skilled person itself explanatory and therefore require no further explanation.

In the case of an ISDN network the messages (Messages) functional nature and are transmitted in the ISDN D channel. at an analog network is it Ringing pulses and busy signals. After the connection to all information between the units by FSK signaling in transmit voice band, specifically in accordance with the ETSI specifications ETS 300659-1 [4] and ETS 300659-2 [5].

In Fig. 5 is the construction of an additional message CP CONNECT shown that the notification of the calling unit the part of the called unit of the structure of the compound serves. This notification is required to in the CM layer to set the processes in motion. The Nachrichtenartkodierung is: 0x40 0100 0000B, and the format follows GSM04.7 / Chapter 11 [2].

The layer DL enables the connection manager (layer CM) to send and receive messages with the partner unit, it provides the bit error and realized for a message in the layer CM, a warning signal (Mark Signal).

In FIG. 6, the format of a message in the data link layer shown. The "mark signal" comprises a block of 80 ± 25 bits. The "Message Type" field includes one octet and contains a binary coded identification code for the message. The coding for a DL_SMS_INFO Message Type is: 011H 0001 0001B. The coding is a DL_SMS_ERROR Message Type: 012H 0001 0010 B.

The "Message Length" field comprises one octet and contains the binary coded number of octets of the message (with the exception the octets of the message type, the Message Length and the checksum). Overall, a message length is up to 255 Octet allowed. The field "checksum" comprises one octet and contains the two compliments of the sum of all the octets in the Message, starting from the "Message Type" octet to the end, modulo 256th

In case of a checksum error, the data link layer sends the receiving entity a message of Type "DL_SMS_ERROR" sent to the (original) unit. In this message, the data field is empty and the message length (Message Length) is set to zero. The data link layer the sending unit must thereupon the last sent message to be repeated.

For the physical layer should also be noted that in the case an FSK signaling a half-duplex 1200 baud modulation can be used. In case of DTMF signaling will each octet of a message in the data link layer in the higher (upper) and lower (bottom) nibble divided up. Each nibble is encoded with a DTMF bit. First, the upper nibble is sent and then the lower.

In the case of DTMF signaling, the signal is the DL message is omitted.

Regarding the signaling method are various possibilities of combination; Normally, in the telecommunication terminal a selection permanently installed, then the User ceases to change.