FR2803972A1 - Mobile telephone radiocommunications network increased capacity system having mobile telephone first base units transmitting/receiving and second base terminal with settable frequency offset and fixed terminals communicating. - Google Patents

Abstract

The radiocommunications network system has base stations (1) with transmitters and receivers (2) and a command unit (3), communicating with a mobile telephone (6). A base station (7) associated with a fixed terminal (11) has a frequency offset (9) setting a second range of frequencies during reception.

Description

The present invention relates to a radiocommunication network capable of communicating directly with a fixed terminal. Radiocommunication networks are known, in particular the network known by the name GSM / GPRS allowing transmission of speech and data signals. The network then comprises a speech channel, called GSM, for which the network is structured according to a circuit mode, and a data channel, called GPRS for which the network is structured according to a packet mode.

These radiocommunication networks are intended to connect mobile terminals to one another or mobile terminals to fixed stations connected to an external switched network but, in order to avoid saturation of the radio frequencies used for communication between a fixed base station of the radiocommunication network and a terminal registered in the network, it is generally prohibited by operators to use these frequencies to establish communication directly with a fixed terminal which would be integrated into the network, even when the latter is located in a covered area through the network. To ensure communication with a fixed terminal, it is therefore necessary to go through an external network, for example a public switched network to which the management body of the radiocommunication network is attached.

As a result, data transmission is slowed down on the one hand because of the need to establish a relatively long chain of links, and on the other hand because of the speed limitation imposed by the external network either due to an intrinsic limitation of its transmission capacities, ie due to the congestion of this network.

The object of the invention is to increase the transmission capacity with a fixed terminal while respecting the operating rules of the radiocommunication network. With a view to achieving this aim, a radio communication network is proposed according to the invention comprising a series of fixed base stations each comprising a transmitter / receiver equipment associated with a control member, the base stations being adapted to communicate with at least one mobile terminal at a frequency chosen from a first frequency range by a control member of the corresponding base station, at least one base station being associated with a fixed terminal and comprising for a link with this fixed terminal a transposer of frequencies controlling a transmission at a frequency chosen from a second range of frequencies upon reception of an order from the control member.

Thus, while using the communications management of the existing radiocommunication network, and without using the usual frequencies of transmission of this radiocommunication network, which correspond to the first range of frequencies of the network according to the invention, it is possible to ensure a direct link between the radiocommunication network and a fixed terminal so that the effective speed is improved.

According to an advantageous version of the invention, the fixed terminal is suitable for transmission on a single frequency of the second frequency range. Thus, the frequency transposition is simplified. In the case where several fixed terminals are associated with the same base station, the fixed terminals are preferably suitable for transmission at the same frequency of the second frequency range.

Other characteristics and advantages of the invention will appear on reading the description which follows in relation to the attached single figure which is a schematic representation of the radiocommunication network according to the invention.

With reference to the figure, the radiocommunication network according to the invention comprises, in a manner known per se, a series of base stations 1 of which only two have been shown in the figure, each comprising a transmitter / receiver equipment 2 associated with a control 3. The base stations 1 are connected to a management unit 4 itself connected to an external network 5, for example a public switched network. The base stations 1 are adapted to communicate with mobile terminals 6 of which only one has been shown in the figure.

In this network known per se, the mobile terminal 6 communicates with the base stations 1 by means of a first range of carrier frequencies. In the case of a GPRS network, this first frequency range is between 900 MHz and 950 MHz and the data transmission rate can reach 170 kbit / s, or even 384 kbit / s for GPRS modulation of the EDGE type.

According to the invention, the radiocommunication network further comprises at least one base station 7 comprising like the base stations 1 a control member 3 adapted to communicate with the management member 4, but unlike the base stations 1 la base station 7 comprises a transmitter / receiver 8 operating in a second frequency range, for example a frequency range known under the name WLL for which the transmission frequencies are several Gigahertz, in particular 3.4 GHz at 3, 5 Ghz, or 26 Ghz or 28 Ghz. In order to be able to transmit in the second frequency range while the orders given by the control unit contain instructions for transmission at frequencies of the first frequency range, the base station 7 is equipped with a frequency transposing unit 9 which transcribes the orders of the control member 3 to make them executable by the WLL transmitter / receiver 8.

The base station 7 is associated with fixed switches 10 to which fixed terminals 11 are connected. Preferably, the WLL transmitter / receiver 8 of the base station 7 is provided to ensure transmission on different carrier frequencies of the second range frequencies while the switches 10 are provided to operate at a single frequency. The management of the frequencies WLL is then facilitated, the frequency transposing member 9 simply having to systematically transpose the orders of the control member 3 to the corresponding frequency of the switch 10 receiving the transmission. This single frequency can be used for the connection with several fixed terminals 11.

From the point of view of the management unit 4, the switches 10 appear as mobile terminals which are constantly registered in the cell corresponding to the base station 7 but the frequencies of the first range of frequencies are immediately released by the unit frequency transposer 9. It will be noted in this connection that the geographical area covered by the base station 7 is preferably also covered by a base station 1 in order to allow normal operation of the network when a mobile terminal 6 travels in this geographical area.

Of course, the invention is not limited to the embodiment described and it is possible to make variant embodiments without departing from the scope of the invention as defined by the claims.

In particular, although the radiocommunication network according to the invention has been illustrated with a single base station 7 comprising a transmitter / receiver equipment in the second frequency band, it is possible to provide several base stations of this type distributed over the network .

Although in the preferred embodiment it has been indicated that the switches are suitable for transmission on a single frequency, it is possible to provide for transmission on different frequencies, the frequency transposing member 9 then ensuring the management of the transmission frequencies by the transmitter / receiver equipment 8.

It will further be noted that the network according to the invention makes it possible to ensure a transmission either between a mobile terminal 6 and a fixed terminal 11, or between two fixed terminals, whether these are attached to the same base station 7 or to 7 different base stations.

Claims (3)

<U> CLAIMS </U> 1. Radiocommunication network comprising a series of fixed base stations (1) each comprising a transmitter / receiver equipment (2) associated with a control member (3), the base stations (1) being adapted to communicate with at least a mobile terminal (6) at a frequency chosen from a first frequency range by the control member (3) of the corresponding base station, characterized in that it comprises at least one base station (7) associated with at least one fixed terminal (11) and comprising a frequency transposing member (9) controlling a transmission at a frequency chosen from a second frequency range when an order from the control member (3) is received. 2. Radiocommunication network according to claim 1, characterized in that the fixed terminal (11) is suitable for transmission on a single frequency of the second frequency range. 3. Radiocommunication network according to claim 2, characterized in that it comprises several fixed terminals associated with the same base station (7) and in that the fixed terminals (11) are suitable for transmission at the same frequency of the second frequency range.