FR2832861A1 - Antenna/several radiocommunications networks coupling has down channel first/second station coupling using passive coupler with insertion losses below 1 dB - Google Patents

Abstract

The station coupling mechanism has an antenna coupling a down channel for a first station (BTS1) or second station (BTS2) coupling on the output. The coupling is passive and has an insertion loss below 1 dB.

Description

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DEVICE FOR COUPLING RADIOCOMMUNICATION STATIONS
ON AN EMISSION / RECEPTION ANTENNA
The invention relates to an installation for a radio communication network and more specifically to a device for coupling radio network stations on the same transmitting / receiving antenna. The invention is particularly interesting for coupling on the same antenna several stations of the same network, of several networks of the same type of networks and / or different types of networks.

 Different radio networks already exist or are under development. GSM, DCS, UMTS and other networks are particularly known. Each network is characterized in particular by its (or its) transmission / reception frequency (s), within a frequency band specific to the type of network to which it belongs. For example, a GSM-type network is allocated a large number of frequencies (about 60), each frequency being associated temporarily with the transmission of a communication passing through the network. The frequencies allocated to each GSM type network are around a frequency of 0.9 GHz, a characteristic frequency of GSM networks. In another example, a UMTS-type network is allocated a small number of frequencies (approximately 5), all the communications transiting on the network passing in series on a fixed frequency signal, each communication being identified by an associated code which precedes while in transit over the network. The technical characteristics of each type of network are defined in international standards and each type of network is associated with known communications protocols.

 Each radiocommunication network comprises in particular a core network and access modules to

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 network core. An end-user with a personal station, such as a mobile phone, connects to an access module over a wireless link to access the backbone and make or receive a call.

 The core network consists of radiocommunication elements able to exchange digital communications (or communications packets) between them, via a radio link, a wired link or by any other means.

 An access module at the core network includes a base station, and an antenna E / R (for transmitting and receiving antenna). The station comprises means for exchanging (transmitting or receiving) communications with the core network. The station also comprises means of connection to the antenna E / R, to receive a communication from a final station (mobile or fixed) or to send a call to a final station via the antenna E / R. A network access module must be installed in an open reception site and preferably in height: a pylon dedicated to this use in a rural environment, a terrace of a building in an urban environment, etc. The antenna of an access module must indeed be in view of a station possibly mobile and wishing to connect, in order to ensure a good transmission of communications between them over the air.

 The word communication must be understood, here and in all that follows, in the broadest sense: a communication is a transmission between two stations, a set of digital data relating for example to an oral communication, to instructions, digital data packets, etc. A communications packet is then a set of one or more communications made in parallel. We will also say that two stations (fixed or mobile) and / or elements of a heart

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 network exchanges a communication when one transmits a communication to another.

 In practice, different radio operators each have their own network (core network and access modules) and offer an end user a connection to this network.

 The cost of a complete network is quite high because it requires a large number of access modules (about 10,000 for a country such as France), which varies in particular according to the radio traffic (number of simultaneous calls on the same area geographically) and terrestrial congestion (residential areas, mountains, etc.).

 Also, each operator wishing to own his own network must invest a substantial sum for its realization and installation. The development by the same operator of a network of a second type requires a similar investment.

 In addition, the strong growth in the number of mobile stations (and therefore the number of calls exchanged on the same network) leads to the need for denser networks capable of simultaneously or in parallel carrying an increasing number of calls.

 To densify a network supposes in particular to increase the number of modules of access. This poses serious problems of infrastructure, especially in urban areas, where the need for access modules is important for the same network and where the number of possible reception sites is very limited.

 Finally, an increasing number of operators wish to exploit each one's own radio network and its own equipment.

 To limit the cost of installing (or extending) a radio network, operators plan to pool elements of their respective networks.

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 A solution developed in Canada in particular consists of a unique specific network for a given type of network. For example, a single GSM network is installed and all the operators share the capacity of access to the network (frequency rental). This solution is only interesting in a geographical area where there is no network yet as it would require significant modifications of existing network infrastructures. In addition, this solution involves installing a network for each type of network.

 Another solution is to pool only the access modules (stations and antennas E / R) of several networks, each network also having its own core network. A multiplexing element allows each of the operators to couple on the common access module. However, the equipment currently marketed only allows two network operators of the UMTS type to share common modules, because for this type of network, each operator has a very small number of frequencies.

The equipment currently marketed is not counter-usable in the case where a large number of signals of different frequencies pass simultaneously to one point of the network, which is the case for networks of GSM or DCS type. Moreover, the use of these materials requires a significant modification of the existing network infrastructure and a consequent oversizing of the common access modules. This limits the interest of these materials in areas of low traffic: rural and / or suburban areas.

 Another solution is to share only part of the access modules, and in particular, the antenna E / R of these modules.

 For this, we currently use a hybrid coupler 3dB to connect two base stations on the same antenna E / R. We recall that a hybrid coupler

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 provides on its output a signal resulting from the addition of the signals it receives on its inputs. In practice, this solution can be envisaged only in the case of signals having very different frequencies, in other words only for stations belonging to networks of different types. Indeed, two signals of very similar frequencies can not be dissociated after being added. In addition, the use of a 3 dB coupler, by its very construction, causes, for each station, a loss of radiated power of the order of 50 to 75% and a decrease in the coverage area of the order of 30%, that it is necessary to compensate by oversizing the station concerned, or by increasing the number of access modules.

 As we have just seen, the current solutions for pooling elements of radio networks are not satisfactory: they take poor account of existing networks, they are not usable for any type of network, they entail costs installation and or oversizing of large networks.

 An object of the invention is to propose a coupling device to allow two (or more) radio network stations of the same type to share the same transmitting / receiving antenna, without causing over-sizing or overhead of the elements of the or networks.

 Another object of the invention is to propose a coupling device to allow two (or more) stations to share the same transmitting / receiving antenna, without causing oversizing or overhead of the elements of the network or networks, and whatever type of networks they belong to.

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 Thus, the invention relates to a device for coupling radiocommunication network stations on an E / R antenna, comprising a downlink coupling circuit for coupling a transmission channel of a first station of a first type of network or an emitting channel. a second station of the first type of networks on an output of the downlink coupling circuit.

 According to the invention, the downlink coupling circuit is a passive circuit having insertion losses of less than 1 dB.

 It is recalled that the insertion losses of a coupling circuit are equal to the power of a signal obtained at the output of the circuit considered, divided by the power of a signal received by the circuit on an input.

 With such a downlink coupling circuit, it is possible to couple on the same antenna the transmitting channels of two stations, different but belonging to networks of the same type. The coupling is finalized by connecting the output of the down coupling circuit to the antenna. With the invention, the coupling is achieved without oversizing the stations sharing the antenna and without increasing the overall number of stations (and therefore access modules) of a network. Moreover, since two stations share the same antenna, it becomes possible to limit the total number of antennas when several radio networks of the same type are installed on the same geographical area.

 The invention can be implemented whatever the type of networks considered: GSM; DCS, UMTS or any other type of network having given characteristics, especially in terms of frequency.

 The device of the invention is advantageously supplemented by a rising coupling circuit for coupling a receiving channel of the first station or a receiving channel of the second station to an output of a duplexer whose input is connected to the output of the circuit. downlink coupling. An entry / exit from

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 duplexer is in this case connected to the antenna to finalize the coupling on the antenna.

 The device thus completed makes it possible to ensure a total coupling of the two stations on the antenna by coupling their transmitting paths and their receiving paths.

 The device of the invention is further advantageously completed by a multiplexer comprising a first primary terminal connected to an output of the duplexer, and a second primary terminal connected to a duplexed input / output of a third station of a second type of network. A secondary terminal of the multiplexer is in this case connected to the antenna to finalize the coupling.

 The device thus completed allows the coupling of three stations on the same antenna, two stations of a first type and a station of a second type.

 More generally, an improved device according to the invention will be achieved by associating one or more uplink circuits with one or more downstream circuits by means of multiplexers, as a function of the number of stations to be coupled on the same antenna and the type of networks to which they belong.

 According to one embodiment, the uplink coupling circuit comprises: an amplifier having an input connected to the output of the duplexer, and a first coupler comprising an input connected to an output of the amplifier and outputs connected to the reception channels of the amplifier; the first station and the second station.

 According to another embodiment, the down-coupling circuit comprises: a second coupler, a primary terminal of which is connected to a first input of the down-coupling circuit;

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 two filters, each comprising an input connected respectively to a first and a second secondary terminal of the second coupler, and - a third coupler of which a first and a second primary terminals are respectively connected to an output of the filters, and a first and a second second secondary terminals are respectively connected to a second input and an output of the down-coupling circuit, the first input and the second input of the down-coupling circuit being respectively connected to the transmission channels of the first station and the second station, the output of the downlink coupling circuit being connected to an input of the duplexer.

 The first coupler, the second coupler or the third coupler are in turn 3 dB couplers.

The filters are chosen capable of passing a signal transmitted by the first station and blocking the signal transmitted by the second station. These are, for example, filters comprising a series of cavities coupled together to form a resonant circuit around the frequency of a signal emitted by the first station.

 The invention will be better understood and other features and advantages will appear on reading the description which follows, examples of implementation of a coupling device according to the invention for radio networks. The description is to be read in conjunction with the appended drawing in which: - Figure 1 is a diagram of a coupling device of two stations, according to the invention - Figure 2 is a diagram of a coupling device of five stations, according to the invention.

 In a first exemplary embodiment shown in FIG. 1, the coupling device according to the invention makes it possible to couple two stations BTS1, BTS2 to

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 the same transmitting / receiving antenna (not shown). The two stations BTS1, BTS2 are of the same type, for example of the GSM type. They are part of the same network or two different networks.

 Each station BTS1, BTS2 includes a TX output (still called downlink) and an input RX (still called upstream). Each station also includes means of connection to its own radio network (not shown).

 The coupling device of FIG. 1 comprises a rising coupling circuit C1, a downward coupling circuit C2 and a duplexer D.

 The duplexer D comprises an input D1, an output D2 and an input / output D3. The duplexer D is made according to a scheme known elsewhere. When it receives a signal on its input D1, it transmits it identically on its input / output D3. Conversely, when it receives a signal relating to a communication on its input / output D3, it transmits it on its output D2.

 The circuit C1 comprises an input E connected to the output D2 of the duplexer D, and two outputs S1, S2 connected to the inputs RX of the stations BTS1, BTS2.

When it receives a signal on its input E, the circuit C1 supplies, on its outputs S1, S2, two identical signals, images of the signal received on its input E.

 The downlink coupling circuit C2 comprises an output S connected to the input D1 of the duplexer D and two inputs E1, E2 connected to the TX outputs of the stations BTS1, BTS2. The circuit C2 is a passive circuit having no or very little insertion loss (less than 1 dB). When it receives a signal on one or other of its inputs El or E2, the circuit C2 provides on its output on its output S an identical signal, and the same power (or slightly lower power).

 The overall operation of the coupling device is as follows. When one of the stations BTS1 or BTS2 transmits a signal relating to a communication, the signal is

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 transmitted identically (in particular in terms of power) by the C2 circuit to the input D1 of the duplexer D which transmits it on the antenna E / R. Conversely, when a signal relating to a communication is received on the antenna E / R, the duplexer D transmits said signal on the input of the circuit C1, which retransmits it on the inputs RX of the two stations BTS1, BTS2.

 The circuit C1 comprises an amplifier PA, preferably of low noise, and a coupler CO1.

 The amplifier PA comprises an input connected to the input E of the circuit C1 and an output; the coupler CO1 comprises an input connected to an output of the amplifier PA and two outputs connected to the two outputs of the circuit C1. When a signal is received on the input E of the circuit C1, this signal is amplified and then shared. by the coupler COl in two signals, identical to the amplified signal but half power, which are then respectively transmitted to the outputs 81r S2 of the circuit C1. The amplifier PA is chosen so that the signals supplied by the circuit C1 have a level sufficient power to be detected by the BTS1, BTS2 stations. It should be noted that the power of a signal at the output of the circuit C1 may be less than that of a corresponding signal applied to the input of the circuit C1, it is sufficient for a signal output from C1 to be of a level sufficient to to be detected by the first or the second station.

 The circuit C2 comprises two 3 dB hybrid couplers C02, C03, and two filters F02, F03.

 The coupler C02 comprises four inputs / outputs respectively connected to the input E1 of the circuit C2, to a load 50 Q, to an input / output of the filter F02 and to an input / output of the filter F03. Coupler C03 comprises four inputs / outputs connected respectively to an input / output of the CO 2 filter, to a

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 input / output of the filter C03, the input E2 of the circuit C2 and the output S of the circuit C2.

 The filters F02, F03 are identical, they are band-pass filters, centered on the frequency associated with the BTS1 station, able to reject the signals emitted by the BTS2 station and having very low insertion losses.

The filters are for example made by a series of resonance cavities coupled together to obtain a resonant circuit around a frequency including the frequency associated with the BTS1 station. This embodiment is particularly advantageous because it makes it possible to produce filters with a large slope (ie, particularly selective filters) and having a very low bandwidth: this makes it possible to separate very close frequency signals. (case of two signals emitted by stations of the same type of networks). Cavity filters also have the advantage of having very low insertion losses.

Thus, in a practical embodiment, filters having insertion losses of less than 0.8 dB have been obtained. Couplers C02, C03 are known 3 dB hybrid couplers.

 Thus realized, the circuit C2 is a passive circuit, which has low insertion losses.

 The operation of circuit C2 is as follows.

When it receives a signal on its input El (concretely, when the station BTS1 transmits a communication), this signal is divided into two signals of power half and of frequency identical to that of the signal received, the two signals are propagated on the entries filters F02, F03. Since the filters F02, F03 are identical and centered on the frequency of the signals propagated by the coupler C02, the two signals are transmitted to the inputs of the coupler C03. The coupler C03 combines the signals and supplies on its output S a combined signal which is identical, in terms of frequency and

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 particular power, to the signal received on the input E1 of the circuit C2.

 When the circuit C2 receives a signal on its input E2 (concretely, when the station BTS2 transmits a communication), the coupler C03 shares the received signal in two identical signals, with the same frequency and power equal to half the power of the signal received. The two half power signals have a frequency outside the frequency band of the filters C02, C03, therefore the two signals are reflected by the two filters C02, C03 and then combined by the coupler C03, which produces the combined signal (identical to that issued by the BTS2 station), on the input of duplexer D.

 In any case, when one or other of the BTS1 or BTS2 stations transmits a call, said call is received on one or the other of the inputs E1, E2 of the circuit C2 and then transmitted identically on the input of the duplexer D which transmits it to the antenna.

 Conversely, the circuit C1 is used when a communication is received on the antenna and must be transmitted to one or other of the base stations BTS1 or BTS2. A signal received on the antenna arrives on the input / output D3 of the duplexer D, which transmits it on the input of the circuit C1. The signal is amplified by the circuit PA and then divided in two by the coupler C01 which transmits on its outputs, two signals identical to stations BTS1, BTS2.

Each station thus receives the signal received on the antenna and only the station concerned detects and exploits it.

 In a second exemplary embodiment shown in FIG. 2, the coupling device according to the invention makes it possible to couple three BTS1, BTS2, BTS3 stations of GSM type networks, a BTS4 station of a DCS type network and a BTS5 station. a UMTS type network to the same transmitting / receiving antenna (not shown). The device thus makes it possible to couple five

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 different stations belonging to networks of three different types.

 As a reminder, a GSM network, respectively DCS and UMTS, are associated with signals of frequencies close to 0.9 GHz, respectively 1. 8 GHz and 2 GHz. In addition, two different networks transmit signals on different frequencies. In one example, the frequencies 0.936 GHz, 0.955 GHz, 0.965 GHz, 1.85GHz and 2.05GHz are respectively associated with the stations BTS1, BTS2, BTS3, BTS4 and BTS5.

 The coupling device of FIG. 2 comprises a rising coupling circuit C3, two down coupling circuits C4, C5, a duplexer D and a triplexer M.

 The circuit C3 is similar to the circuit C1 of FIG. 1. It comprises an input E and three outputs E1, E2, E3 respectively connected to the inputs RX of the three stations BTS1, BTS2 and BTS3. The circuit C3 (not detailed) comprises an amplifier having an input connected to the input E of the circuit C3, and a coupler comprising an input connected to an output of the amplifier and three outputs connected to the outputs S1 to S3 of the circuit C3. . The coupler transmits on its outputs 3 identical signals obtained by sharing (in terms of power) the signal that it receives on its input. The amplifier is chosen so that the power level of the signals obtained at the output of the circuit C3 is sufficient for said signals to be detected by the stations BTS1 to BTS3.

 The circuits C4, C5 are identical to the circuit C2 of FIG. 1 and are associated in cascade. The circuit C4 comprises two inputs E1, E2 respectively connected to the TX outputs of the stations BTS1, BTS2 and an output S. The circuit C5 comprises for its part two inputs E1, E2 respectively connected to the TX output of the station BTS3 and to the output S of circuit C4. Like the circuit C2, the circuits C4, C5 provide on their output S a signal identical to that

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 received on one or the other of their inputs E1, E2. The circuits C4, C5 each comprise two 3 dB couplers and two filters.

 The C4 filters have a bandwidth centered on the frequency of the signals emitted by the station BTS1 (in the example 0.936 GHz) and are able to reject the signals emitted by the BTS2, BTS3 stations. The C5 filters have a bandwidth centered on the frequency of the signals emitted by the BTS3 station (in the example 0.965 GHz) and are able to reject the signals emitted by the BTS1, BTS2 stations.

 The duplexer D is identical to that of FIG. 1, it comprises an input connected to the output of the circuit C5, an output connected to the input E of the circuit C3 and an input / output.

 The triplexer M comprises three primary inputs / outputs P1, P2, P3 and a secondary input / output PO. The input / output PO of the triplexer is connected to an antenna E / R (not shown) and the input / output Pl is connected to the output of the duplexer D.

 When it receives a signal on its input / output PO, the triplexer M transmits on its input / output P1 the components of the received signal having a frequency close to 0.9 GHz, on its input / output P2 the components of the received signal having a frequency close to 1. 8 GHz and on its input / output P3 the components of the received signal having a frequency close to 2.0 GHz.

sorties Pl à P3, et une entrée/sortie connectée à l'entrée/sortie PO du triplexeur M. Dans l'exemple, le filtre F1 est un filtre passe-bas, choisi de sorte qu'il laisse passer les signaux de type GSM, de fréquence de l'ordre de 0.9 GHz, mais pas les signaux de type DCS ou UMTS. Le filtre F2 est un filtre de type passe-bande, In an exemplary embodiment, the triplexer M comprises three filters F1, F2, F3. Each filter has an input / output connected to one of the inputs /

outputs P1 to P3, and an input / output connected to the input / output PO of the triplexer M. In the example, the filter F1 is a low-pass filter, chosen so that it allows the GSM type signals to pass. , of frequency of the order of 0.9 GHz, but not DCS or UMTS type signals. The filter F2 is a band-pass type filter,

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 chosen so that it passes DCS type signals, but not GSM signals or UMTS signals. Finally, the filter F3 and a high-pass filter, chosen to pass the UMTS type signals but to filter the GSM or DCS type signals.

 Finally, a duplexed TX / RX input / output of the BTS4 station is connected to the input / output P2 and a duplexed TX / RX input / output of the BTS5 station is connected to the input / output P3 of the triplexer M.

 The overall operation of the device of Figure 2 is as follows. When a signal is emitted by one of the stations BTS1, BTS2 or BTS3, it is transmitted identically by the circuits C4, C5 on the input of the duplexer D. Received by the triplexer M and more particularly by the filter FI, the transmitted signal is sent to the antenna. When a signal is emitted by the BTS4 station or the BTS5 station, it is transmitted directly to the antenna by the triplexer M.

 When a signal is received by the triplexer M, its GSM component (frequency close to 0.9 GHz) is transmitted to the duplexer D, its DCS component (frequency close to 1. 8 GHz) is transmitted to the station BTS4 and its component UMTS ( frequency around 2.0 GHz) is transmitted to the BTS5 station. If the signal is received by the duplexer D, it is transmitted to the circuit C3. The circuit C3 shares that it receives in three signals which are transmitted to the stations BTS1, BTS2, BTS3 and only the station concerned exploits it.

 Other embodiments of the device according to the invention can be easily deduced from the example of FIG. 2.

 Thus, if the stations to be coupled on the antenna belong to networks of two different types, the triplexer M will be replaced by a duplexer. More generally, depending on the stations to be coupled on the antenna, the triplexer can be replaced by a multiplexer

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 comprising as many primary inputs / outputs as network types and a secondary input / output.

 If only two GSM network stations (instead of three) are to be coupled on the antenna with a DCS type station and a UMTS type station, the device of Figure 2 is modified as follows: the circuit C5 is deleted, the output S of the circuit C4 is connected to the input of the duplexer D and the circuit C3 and replaced by the circuit C1 with two outputs.

 In the same spirit, starting from the example shown in FIG. 2, if a second DCS-type network station is to be coupled to the antenna, the device of FIG. 2 is modified as follows: a device similar to FIG. that of FIG. 1 and comprising a circuit C1, a circuit C2 and a duplexer is connected between the two stations of the DCS type and the input P2 of the triplexer M. The central frequency of the filters of the circuit C2 will simply be chosen equal to the frequency characteristic of one of the DCS stations.

 Still other achievements are of course possible. In general, a device according to the invention is made by associating one or more circuits C1, and / or one or more circuits C2 by means of multiplexers, as a function of the number of stations to be coupled to the antenna and of the type networks to which they belong.

Claims (8)

1. Device for coupling stations (BTS1, BTS2) of radiocommunication networks on an E / R antenna, comprising a downlink coupling circuit (C2) for coupling a transmitting channel of a first station (BTS1) of a first type of networks or a transmission channel of a second station (BTS2) of the first type of networks on an output of the downlink coupling circuit (C2), the device being characterized in that the downward coupling circuit (C2) is a passive circuit having insertion losses of less than 1 dB.  2. Device according to claim 1, characterized in that it also comprises a rising coupling circuit (Cl) for coupling a reception channel of the

 first station (BTS1) or a receiver channel of the second station (BTS2) to an output of a duplexer (D) whose input is connected to the output of the downlink coupling circuit (C2).  3. Device according to one of claims 1 to 2, characterized in that it also comprises a multiplexer (M) comprising a first primary terminal connected to an output of the duplexer, and a second primary terminal connected to a duplex input / output a third station of a second type of network.  4. Device according to one of claims 2 to 3, characterized in that the upstream coupling circuit (Cl) comprises: an amplifier (PA) having an input connected to the output of the duplexer (D), and - a first coupler (CO1) comprising an input connected to an output of the amplifier (PA) and outputs (Sl, S2) connected to the receiving channels (TX) of <Desc / Clms Page number 18>  the first station (BT8l) and the second station (BTS2).  5. Device according to one of claims 1 to 4, characterized in that the downlink coupling circuit (C2) comprises: a second coupler (C02) having a primary terminal connected to a first input (El) of the coupling circuit descending (C2), - two filters (F02, F03), each comprising an input connected respectively to a first and a second secondary terminal of the second coupler (C02), and - a third coupler (C03) of which a first and a second primary terminals are respectively connected to an output of the filters (F02, F03), and whose first and second secondary terminals are respectively connected to a second input (E2) and an output (S) of the downlink coupling circuit (C2) , the first input (E1) and the second input (E2) of the downlink coupling circuit (C2) being respectively connected to the emitting channels of the first station (BTS1) and the second station (BTS2), the output (S) of the downlink coupling circuit (C2) being connected to an input (D1) of the duplexer (D).  6. Device according to claim 5, characterized in that the filters (F02, F03) of the downlink coupling circuit are filters able to pass a signal received on the first input (El) of the downlink coupling circuit (C2), and rejecting a received signal on the second input (E2) of the downlink coupling circuit (C2).  7. Device according to claim 6, characterized in that the filters (F02, F03) are cavity filters comprising a series of resonant cavities coupled together. <Desc / Clms Page number 19>  8. Device according to one of claims 6 to 7, characterized in that the first coupler (COI), the second coupler (CO2) or the third coupler (CO3) is a 3 dB coupler.