Transmission base for a radio telephonic communication arrangement.

The present invention relates to a transmission for a basic telephone radio communication device as divulge for example in EP-A-0097541.

Discloses communication radio telephone devices which comprise a plurality of fixedly implanted transmission bases, connected to a telephone network and to ensure a radio link with a set of mobile stations moving in the area covered by the communication device radio telephone. In known devices, a transmission base comprises at least one receiving antenna of radio electrical signals; a reception coupling member connected to the receiving antenna; a series of receiver members connected to the reception coupling member; a series of digital processing units each connected to a receiver member, a line of a telephone network, and a management unit; a series of transmitter members each connected to a digital processing unit; a coupling member connected to the emitters in transmission bodies; and a transmitting antenna connected to the emission coupling member.

We also know that to ensure security of transmission between the base transmission and mobile stations regardless of the existing electrical radio obstacles between the base transmission and mobile stations, such as unfavorable terrain configurations or certain buildings forming a radio electrical screen, it is desirable to carry out a transmission with frequency hopping, each frequency is assigned in a different way by the radio-electric barriers.

To perform frequency hopping transmission with existing databases whose structure has been recalled above, it is necessary that the program in coupling member is a broadband device operating in hybrid mode. Such coupling members have the disadvantage cause power losses that are based on the number of floors of the transmission base so it is necessary to provide a very important initial power for transmission bases to ensure simultaneously transmitting a large number of communications.

To reduce power requirements while providing frequency hopping, the option to group the receiving members and issuers organs in common modules associated with operating in a coupling cavity mode. Such a device, however, requires the establishment of a highly complex matrix switch for connection between the transceiver modules on one hand and digital processing units other.

An object of the present invention to provide a relatively simple structure of transmission base that can easily operate in conjunction with a coupling member broadcast of broadband or cavities kind.

In order to achieve this object there is provided according to the invention a transmission basis for an electrical radio communication device, the transmission base having at least one receiving antenna of radio electrical signals; a reception coupling member connected to the receiving antenna; a series of receiver members connected to the reception coupling member; a series of digital processing units each connected to a receiver member, a line of a telephone network and a management unit; a series of organs emitters connected to the digital processing units; a coupling member connected to the emitters in transmission bodies; and a transmitting antenna connected to the transmission coupling member; wherein the digital processing units are connected to the transmitter members via a series of link lines, each link line being connected firstly to a digital processing unit and secondly to the transmitter members in parallel connections and wherein each transmitter member includes a switching member controlling communication on the transmitter member associated with one of the connecting lines.

According to one embodiment of the invention wherein the transmission coupling member is of the cavity type, each transmitter member being adapted to transmit a signal at a fixed frequency, each switching element comprises posts detecting means transmission from a digital processing unit containing data to be transmitted to the frequency of the transmitter member to which the switching member is associated, and ensures the placing in communication with the transmitter member concerned the connection line correspondingly.

According to an advantageous embodiment of the invention in which the emission coupling member is of the cavity and in which a permanent emission must be provided to a beacon frequency, body issuer of the beacon frequency ensures emission useful whenever data to be transmitted at the beacon frequency are present on a connection line, and a stuffing transmission when no data to be transmitted at the beacon frequency is present on one of the connecting lines.

According to one embodiment of the invention in which the emission coupling member is hybrid type, each switching element provides a permanent connection with one of the connecting lines.

According to an advantageous embodiment of the invention in which emissions are made at a number of frequencies greater than the number of digital processing units, the emission coupling member is hybrid type and a permanent issue must be ensured in a beacon frequency, the base transmission includes a tag transmitter member in addition to the transmitter members associated with the digital processing units, the tag transmitter member being associated with a switching member having messaging detecting means from the all of the digital processing units and controlling a tamping transmission to the beacon frequency when none of the other transmitter members will emit a signal on the beacon frequency.

Other characteristics and advantages of the invention will appear on reading the following description of a preferred embodiment without limiting the invention in connection with the attached single figure which illustrates schematically the structure of a base transmission according to the invention.

Referring to the figure, the basic transmission of the invention comprises a receiving antenna of radio electrical signals 1; a reception coupling member 2 connected to the receiving antenna; a series of 3-organ connected to the reception coupling member.

In the illustrated embodiment, the number of receiver elements has been limited to three but this number may of course be increased depending on the number of communications, the base must transfer.

Each of the receiving members 3 is connected to a digital processing unit 4 itself associated with a 5 line of a telephone network and a common management unit 6. The reception 2 coupling member operating in hybrid mode and each receptor organs starts every moment listening to a radio electric wave whose carrier frequency it is communicated by the digital processing unit which it is associated according to control signals given by the management unit in which frequency hopping rules were introduced during the startup of the basic transmission. Bodies 3 receptors are thus able to perform in a conventional manner amplification and conversion into digital signals of radio electric signals received while the digital processing units provide decoding and transmission over the telephone network signals digital receipts that include themselves several telephone calls by multiplexing rules in time known in themselves.

Furthermore, each of the digital processing unit 4 is connected to a line of a series of connecting lines 7 arranged in parallel to send messaging to the transmitter members 8. Each transmission message includes data to be transmitted, the indication of the frequency with which these data are to be issued and, if appropriate, other information such as the transmission power. The transmitter members 8 are each connected to all of the bonding lines in parallel connections via switching elements 9 for controlling the establishment of communication of the associated transmitter member with one of the connecting lines 7. The organs transmitters 8 are connected to a transmission coupling member 10 itself associated with a transmitting antenna 11.

In the preferred embodiment of the invention, the transmission coupling member 10 is of the cavity type, that is to say that each transmitter member 8 associated with the coupling member 10 is adapted to transmit a signal to a fixed frequency. In this case, the number of transmitter members 8 is the number of fixed frequencies which it is desired to transmit. In particular, although the number of organs issuers represented 8 was limited to four for reasons of simplicity of the figure, this number may be increased or reduced depending on the number of fixed frequencies that you want to use, the number minimum however being equal to the number of digital processing units. Furthermore, the control unit 6 performs a synchronization of the digital processing units 4 at each instant a single digital processing unit sends a transmission message containing a given transmission frequency. The frequency jumps are made in installments over time by each of the digital processing units according to pre-established rules introduced in the management unit at the establishment of the facility. In this embodiment, each switching device comprises transmission of message detection means from digital processing units so as to determine that the digital processing units to be connected to the transmitter 8, to which the body switching is associated. Each time a switching member 9 detects that the data must be transmitted at the frequency of the transmitter member with which it is associated, the switching element provides the connection with the corresponding connecting line.

The transmitter body and in communication ensures conventionally processing the data and transmits the modulated signal corresponding to the transmitting antenna 11, which then provides a useful modulated emission.

In the case where it is desired to ensure continuous emission at a frequency tag, this tag frequency to serve as a landmark to the mobile stations even in the absence of data transmission, one of the transmitter members 8 is of course adjusted to the beacon transmitter frequency and this provides a useful transmission whenever a message containing transmission data to be transmitted at the beacon frequency is present on a connecting line and a stuffing emission when no modulated signal to be transmitted to the frequency tag is present on one of the connecting lines. According to a decision taken during the development of each system, the jamming program is an unmodulated transmission to the beacon frequency or modulated according to system specific emission rules.

Although in the preferred embodiment, the basic transmission according to the invention is used with a coupling member of the type cavities to reduce the power necessary to its operation, the basic transmission according to the invention can easily be adapted to operating with a coupling member in issue 10 of the hybrid type. In this case, each switching element 9 is controlled to ensure a permanent connection with one of the connecting lines 7 and the base transceiver then functions in the same way as conventional transmission bases whose structure has been recalled to the top of the present description. In this case, the number of transmitters bodies 8 can be limited to the number of digital processing units 4. However, in the case where the number of frequencies to which the broadcasts are made is greater than the number of digital processing units, and it is desired to further ensure a continuous transmission on a beacon frequency, there is advantageously provided a padding transmitter member 8 in addition to the transmitter members associated with the digital processing units. The switching member 9 associated with the padding transmitter member then comprises transmission of message detection means from all of the digital processing units for controlling a tamping transmission to the beacon frequency when none of other transmitter members is transmitting on the beacon frequency signal. Note that in this case the basic transmission according to the invention present another advantage over conventional transmission of bases where a full line comprising a receiving member, a digital processing unit and a transmitting unit must be associated with the beacon frequency .

Naturally, the invention is not limited to the embodiment described and can provide alternative embodiments within the scope of the invention.

In particular, although in the described embodiment have been shown a telephone line 5 associated with each digital processing unit 4, a telephone line can be associated with multiple processing units based on the respective capacities of the telephone line and digital processing units.