GB2303994A

GB2303994A - Mobile radio network emulator

Info

Publication number: GB2303994A
Application number: GB9615708A
Authority: GB
Inventors: Markku Korpi; Emmeran Vollert
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1995-07-28
Filing date: 1996-07-26
Publication date: 1997-03-05
Anticipated expiration: 2016-07-26
Also published as: GB2303994B; FR2737377B1; ITMI961502A0; DE19527815C1; GB9615708D0; ITMI961502A1; IT1283457B1; FR2737377A1

Description

2303994 MOBILE RADIO NETWORK EMULATOR FOR PRIVATE COMMUNICATIONS TERMINALS

The invention relates to a communications arrangement for private communications terminals which are connected to a private communications system.

Private communications networks are formed by means of private communications systems which are partly or fully intermeshed with each other. The intermeshing of the private communications systems is achieved in part by way of private property and in part by way of public communications networks. In this case, the private communications systems can be developed differently with regard to their size when completed, although the form of signalling in the private communications network has considerably more signalling variants than the signalling procedures in the public communications networks, in particular as a result of the additional user facility control. Additional signalling paths, which are directed by way of the public communications networks, are required for this. It is known from EP 0 642 282 Al to realize the additional signalling path between communications systems with the aid of an additional device by way of public telephone and data communications systems.

In private communications systems, furthermore, it may be desirable to connect "stand-alone" or "external" or a couple of private communications terminals, such as, for example, those employed outside or at remote sites to the private communications systems. As such "external" communications terminals, as known, are linked up to a private communications system via dial connections of a public communications network, which offers fewer user facilities, the user facilities provided by the private communication system which can be utilized by the communications terminal are as a result considerably limited. In addition, on account is of signalling errors or maloperations in the public communications networks clear coordination of the private communications system with the private communications terminals is no longer possible.

The present invention therefore seeks to connect stand-alone or external private communications terminals to a private communications system wherein the range of user facilities of a private communications network is preserved.

According to the present invention, there is provided a communications arrangement for private communications terminals which are connected to a private communications system, wherein at least one private communications terminal and the communications system are connected to respective network emulators, forming a pair of network emulators (PNEP), the network emulators being provided with respective means for connection to a public communications network, wherein at least one network emulator has means for connection to a public mobile radio network of the public communications network, and respective switching and control means for automatically establishing dial connections by way of the public communications network in order to realize at least one message path and at least one additional signalling path.

The essential aspect of the communications arrangement according to the invention can be seen in the fact that the communications system and the at least one "external', communications terminal are connected to respective network emulators, forming a pair of network emulators. Respective means are provided in the pair of network emulators for the purposes of connection to a public communications network. The pair of network emulators have in addition respective switching means and control means for the purpose of automatically establishing dial connections by way of the public communications network in order to realize at least one message path and at least one additional signalling path. At least one network emulator and preferably the network emulator which is on the communications terminal side, has means for connection to a public mobile radio network of the public communications network.

By means of the pair of network emulators according to the invention, on the one hand the field of application of the wireless communications terminals is considerably extended and, on the other hand, the full range of user facilities of a private communications network is preserved.

Furthermore, the pair of network emulators may contain means for checking the switching of the dial connection that is related to the pair of network emulators. By checking the dial connection that is related to the pair of network emulators with the aid of a special checking procedure, misconnections are recognized and signalling errors in the connected communications terminal or communications system are avoided.

The network emulator on the communications system side can be connected to the public communications network by way of the public mobile radio network or by way of a wire-bound connection. For this purpose, there are to be provided in the network emulator on the communications system side either radio means in accordance with the GSM-standard or transmission means for transmitting the message information and signalling information by way of, for example, 2-wire connection lines.

Arranged in the network emulator on the communications terminal side there are preferably means for connection to a public mobile radio network - in is i particular radio means in accordance with the GSMstandard. As a result, the mobility of the connected communications terminal is considerably increased.

According to a further advantageous development of the invention, the communications terminal is connected to the network emulator on the communications terminal side in a wireless manner with the aid of a DECTtransmission link or an infrared transmission link, whereby the mobility of the private communications terminals is increased further. The additional signalling path or signalling channel for communicating the additional signalling information can be effected either by way of separate dial connections or Ilinband", that is, with the compressing means which compress or decompress the message path information and multiplex means which multiplex or demultiplex the compressed message path information and the signalling information.

Furthermore, the network emulator on the communications terminal side can advantageously be arranged in the wireless communications terminal itself or in a motor vehicle. when the network emulator is realized jointly with and in a communications terminal, maximum mobility is achieved. The arrangement of the network emulator in a motor vehicle together with a wireless infrared transmission link with the communications terminal increases the acceptance of wireless communications terminals.

For a better understanding of the present nvention, and to show how it may be brought into effect, reference will now be made, by way of example to the accompanying drawings.

1 The block diagram shows a private communications system KS with a transmission interface UPO. Usually, private communications terminals not represented are connected to this transmission interface UPO in a is wire-bound manner. This transmission interface UPO comprises, for the message communication, at least one message path or message channel B for example 64 kBit - and in addition a signalling path or signalling channel with 16 kBit/s. The signalling information provided in private communications networks is communicated in this signalling path, enabling additional signalling information to be provided for the control of additional user facilities which are not offered in public communications networks. The transmission interface UPO can alternatively be realized by means of a private SO-interface - not represented - of an integrated services private communications network ISDN.

A network emulator DPNE-KS is connected to the transmission interface UPO. A transmission connection unit LT realizes the transmission interface UPO in the network emulator DPNE-KS. The transmission connection unit LT and also a connection unit SU are connected to a connection control VST, with units LT, SU being coordinated and monitored by way of a control connection SL by means of the connection control. In the transmission connection unit LT, the signals which are communicated serially from the communications system KS are decoded in accordance with the chosen transmission method - for example, the time-spaceposition-transmission method - and the message information ni and also the signalling information si are separated and communicated by way of a message channel or a signalling channel D to the connection control VST. In a manner analogous to this, the message information ni and signalling information si communicated from the connection control VST are combined to form a serial message stream and communicated to the communications system KS. In the case of an SO-interface, the transmission connection unit LT is to be developed in accordance with the physical and procedural properties of this interface.

The connection unit SU, which is also connected to the connection control VST by way of a message channel B - in this case the additional signalling channel DZ is "in-band" - or by way of a message channel B and an additional signalling channel DZ, has an analog interface a/b by way of which the network emulator DPNE-KS on the communications system side is connected to the public communications system FE. In the following description the public communications system is referred to as the public analog telephone network FE. Alternatively - indicated in brackets - a connection to an integrated services communications network ISDN is possible. The connection to this integrated services communications network ISDN is effected by way of an SO-interface - not represented.

Depending on the variant realized for the communication of additional signalling information si for the realization of additional user facilities in private communications networks - the network emulator DPNEKS is connected to the telephone network FE by way of one or two a/binterfaces a/b. In the case of the first variant realized, the additional signalling information si is communicated by way of an additional message path B, that is, by way of an additional a/binterface a/b by way of the public telephone network FE. In the case of the "in-band" variant of the solution, the message information ni is compressed for example 56 kBit/s and together with the signalling information si is multiplexed to form a bit stream of 64 kBit/s. After a digital-to-analog conversion, the multiplexed information is communicated by way of a message path B or an analog interface a/b respectively by way of the public telephone network FE. In a manner analogous to this, the information which is communicated from the public telephone network FE undergoes analog-to- digital conversion, is demultiplexed and is decompressed. The multiplexing or demultiplexing, the compression or decompression and the analog-to-digital conversion or digital-to-analog conversion are carried out in the connection control VST - indicated by designations KOMP, MUX, CODEC put in brackets.

A subnetwork of the public telephone network FE or of the integrated services public communications network ISDN represents the public mobile radio network GSM - indicated by means of broken lines. The conversion of the signalling and message protocols and also the switching of the message information ni between the public mobile radio and telephone network GSM, FE, and vice versa, is carried out by means of the respective communications network GSM, FE. A network emulator DPNE-KE is connected in a wireless manner to the mobile radio network GSM on the communications terminal side. For this connection, the network emulator DPNE-KE has a GSM-radio portion FT-GSM, in which the physical and procedural properties of the standardized GSM-air interface are realized. The mobile radio portion FT-GSM is connected to a connection control VST by way of at least one message channel B and an additional signalling channel DZ, with the connection control being additionally connected to an infrared radio portion FT-INF. Depending on the way, as explained above, in which the additional signalling information si is communicated, one or two message channels B and one signalling channel DZ are decoded in the mobile radio portion FT-GSM and the corresponding message and signalling information ni, si is communicated to or received by the connection control VST and combined in accordance with the GSMstandard for the air interface or is transformed into is the respective radio signals. In the connection control VST, depending on the way in which the additional signalling information si is communicated, the latter is taken from the second message channel B or in the case of an "in-band"-embodiment the incoming message information undergoes analog- to-digitalconversion, is demultiplexed and decompressed and subsequently is processed in an appropriate manner in the connection control VST.

Alternatively, the connection unit SU can be replaced by a radio portion FT-GSM for the connection to the public mobile radio network GSM, whereby the network emulator DPNE-KS on the communications system side is no longer connected to the public communications network (FE) in a wirebound manner, but in a wireless manner. This variant embodiment is indicated in the connection unit SU which is represented by the designation (FT-GSM).

A private communications terminal KE is connected to the infrared radio portion FT-INF of the network emulator DPNE-KE on the communications terminal side by way of the wireless transmission link INF, that is to say, this communications terminal KE does not represent a terminal of the public telephone network FE, but represents a terminal of the private communications system KS. This means that in the case of a connection request of this communications system KS, a connection is always established with the communications system KS. The communications terminal represents, for example, a telephone communications terminal or a multifunctional communications terminal of a private communications network. Alternatively, the'connection of the private communications terminal KE can be connected to the network emulator DPNE-KE by way of a wireless radio link DECT in accordance with the DECT-standard (Digital European Cordless Telephone), in which case the communications terminal KE is to be provided with a corresponding radio unit. Furthermore, the private communications terminal KE can be connected to the network emulator DPNE- KE in a wirebound manner - not represented.

When a request is made by the private communications terminal KE for a connection to be established, this request is reported to the connection control VST in the network emulator DPNE-KE on the communications terminal side by means of corresponding signalling. In response to this, a connection by way of the public telephone network FE to the network emulator DPNE-KS on the communications system side is automatically established by means of the connection control and, after the connection has been successfully established, the connection wish is reported to the communications system KS. In the course of establishing this connection, a checking procedure is carried out, wherein there is communicated from the connection control VST of the network emulator DPNE-KE on the communications terminal-system side to the connection control VST of the network emulator DPNE-KS on the communications system side numerical and identifying information, with the aid of which a check is made to see whether a connection related to the pair of network emulators was established by way of the public telephone network. Given a positive result of the check, acknowledgement information is sent back effecting an increase in the numerical information in the network emulator DPNE-KE on the communications terminal side. Subsequently, the free-line signal is communicated, by way of the infrared or DECT tran'smission link, to the private communications terminal KE and, as a communications network readysignal, is indicated there to a subscriber in an acoustic and/or visual manner. The signalling signals is si which are to be communicated are recognized or formed in the connection control VST and communicated, according to the manner of communication, to the respective network emulator DPNE, lying opposite, by way of the public communications network FE.

In this case, the network emulator DPNE-KE, KS on the communications terminal side and the communications system side form a pair of network emulators PNEP, which in the case of a connection request automatically establish, control and clear a respective connection to their network emulator partner DPNE, with the signalling information si being communicated according to the method of communication used - separate communication path or "in-band" transmission. By using the pair of network emulators PNEP, it is possible to offer all additional user facilities of a private communications network, going beyond those of the public communications network FE (ISDN), to "external or remote" private communications terminals KE as well By using a wireless connection of the network emulator DPNE-KE at least on the communications terminal side, maximum flexibility is achieved that is particularly advantageous in particular when used in mobile devices, such, as for example, motor vehicles or watercraft. Alternatively, the network emulator DPNE-KS on the communications system side can also be connected to the public mobile radio network GSM in a wireless manner. In this case, it is merely necessary to replace the connection unit SU with a mobile radio portion FT-GSM not represented - and adapt the connection control VST in an appropriate manner.

Given appropriate design of the pair of network emulators PNEP, both individual and also a few, that is small groups of, external private communications terminals KE can be connected to a private communications system KS.

is

Claims

1. Communications arrangement for private communications terminals which are connected to a private communications system, wherein at least one private communications terminal and the communications system are connected to respective network emulators, forming a pair of network emulators (PNEP), the network emulators being provided with respective means for connection to a public communications network, wherein at least one network emulator has means for connection to a public mobile radio network of the public communications network, and respective switching and control means for automatically establishing dial connections by way of the public communications network in order to realize at least one message path and at least one additional signalling path.

2. Communications arrangement according to claim 1, wherein means are provided in the pair of network emulators to check the switching of the dial connection that is related to the pair of network emulators.

3. Communications arrangement according to claim 1 or 2, wherein the network emulator which is associated with the private communications system has means for connection to the public mobile radio network of the public communications network.

4. Communications arrangement according to claim 1 or 2, wherein the network emulator which is associated with the private communications system has means for wire-bound connection to the public communications network.

5. Communications arrangement according to one of the claims 1 to 4, wherein the network emulator which is associated with the private communications terminal has means for connection to the public mobile radio network of the public communications network.

is

6. Communications arrangement according to one of the claims 1 to 5, wherein respective means are arranged in the pair of network emulators for the purpose of connecting at least one wireless communications terminal.

7. Communications arrangement as claimed in claim 6, wherein the connection of a wireless communications terminal is realized with a DECTtransmission link or an infrared transmission link.

8. Communications arrangement according to one of the claims 1 to 7, wherein the network emulator is developed in such a way that in the case of a connection request for the message path and for the additional signalling path between the private communications system and the private communications terminal a respective separate dial connection is established or cleared by way of the communications network.

9. Communications arrangement according to one of the claims 1 to 7, wherein the network emulator has additional compression means and multiplex means and is developed in such a way that after a connection has been established the message information of the message path is compressed and together with the signalling information of the additional signalling path is multiplexed to form an information flow in conformity with a message channel and is communicated by way of the message path by way of the public communications network.

10. Communications arrangement according to one of the claims 1 to 9, wherein the network emulator on the communications terminal side is arranged in the wireless communications terminal.

ii. Communications arrangement according to one of the claims 1 to 9, wherein the network emulator on the communications terminal side is arranged in a motor vehicle.

12. Communications arrangement according to one of the claims 1 to 11, wherein the means for connection to a public mobile radio network are realized in accordance with the GSM-standard.

13. Communications arrangement substantially as herein described with reference to the accompanying drawing.