Reception of radio frequency signals, for example broadcast signals received from a satellite, with an interactive return link using a spread spectrum protocol.

The present invention relates to a transmitting / receiving installation of radioelectric signals at microwave frequencies.

[0002] Currently, distribution of digital terrestrial television programs (e.g., according to one of the DVB-T or DVB-T2 standards), or by satellite (e.g., according to one of the DVB-S, DVB-S2 or DVB-SH standards) ) is widely used around the world. Numerous devices are installed with millions of users.

[0003] Regarding the ground road, the devices to be installed are mainly receiving devices comprising an outdoor unit with a receiving antenna (e.g., a receiver ladder antenna) that transmits modulated microwave radioelectric signals to an indoor unit colloquially known as a terrestrial decoder. digital TV or also STB ("Set Top Box"), via coaxial cable.

[0004] As far as the satellite path is concerned, the devices being installed are mainly receiving devices comprising an outdoor unit with a parabolic reflector that focuses modulated signals at microwave frequencies in a source, called a horn antenna, LNB (English Low Noise Block), which means receive block), wherein the LNB converts the received microwave frequency signals into electrical signals in an intermediate satellite band to transmit them via a coaxial cable to the STB satellite decoder.

[0005] Regardless of whether there is terrestrial or satellite transmission, the decoder includes a demodulation block (DVB-T, DVB-T2, DVB-S, DVB-S2 or DVBSH) which extracts the modulated signal "useful". in the modulated signal sent to the coaxial cable and demodulates the extracted "useful" signal. The demodulated signal "usable" can be, for example, used to display video images on a television screen.

[0006] The offers of broadcasting digital television programs by terrestrial or satellite are today basically purely passive, i.e. one-way service. [0007] However, it may be a useful opportunity to offer services requiring a reverse channel; these are, for example, interactive services (voting, use of content to which access is conditioned by logging in, ordering new services, such as, for example, video on demand). In addition, this reverse channel can find particularly interesting applications in the field of communication between machines ("Machine to machine" in English terminology) or M2M, to control some devices (alarm, heating, ...) and / or to acquire data measured by sensors or meters (gas, electricity ...), located in households.

[0008] A known solution to this problem consists in using a reverse channel by using an ADSL line provided by fixed telephony operators (RTC or the "Public Switching Telephone Network") or a GPRS / UMTS link provided by mobile telephony operators. This solution therefore requires additional equipment and additional subscription; in addition, telephone switching is not particularly suited for sending small volume messages such as voice or control messages (relatively high cost, network saturation problems ...).

[0009] By the terrestrial route, the use of the most appropriate solution, such as DVB-RCT technology (described in the European standard ETSI EN 301 958) has failed due to the costs of the necessary infrastructure.

[0010] Most satellite television offers do not include a reverse channel. However, an example of a bidirectional satellite television transmission system described in patent document EP 0888690 can be cited; this system uses a forward channel in the wide Ku band and a reverse channel in the narrow band L. The system is cumbersome, complicated and expensive, in the sense that it requires the presence of two reflectors (for each of the Ku and L bands) or a special reflector containing a reflector, adapted to receive signals in the Ku band and including an antenna transmitting in the L band. This system also implies the presence of two physical data routing channels, one of the Ku-band antennas for the decoder at home, and the other from the decoder to the L-band antenna. easy to understand,

[0011] Another example of a bidirectional satellite television transmission system is described in patent application WO 2011076791, filed by the applicant. This system uses a forward channel in a wide Ku or Ka band and a reverse channel in a narrow S band or C band, the signals being multiplexed in the same coaxial cable. The amplification of the reflector for receiving signals with microwave frequencies in the Ku or Ka band is used to transmit signals via the reverse path in the S band or in the C band. Despite the gain in gain due to this solution, the fact remains that the loss of the useful signal in the return channel ( in particular when passing through a coaxial cable) is considerable and it is necessary to locate a sufficient amplifier in the outdoor unit. Also,

[0012] In this context, the present invention aims to provide a receiving installation of radioelectric signals at microwave frequencies, also allowing to provide radioelectric signals at microwave frequencies in the reverse channel in an efficient manner from the point of view of its performance, easily adaptable to an already existing one. installation that supports one or more users, developmental and not very expensive.

[0013] To this end, the invention provides a transceiver / receiver installation for microwave radioelectric signals comprising:

- sending / receiving unit containing:

° means adapted to receive electrical signals obtained as a result of processing of radioelectric signals received by terrestrial or satellite radio lines, called electrical signals in the forward channel;

° a demodulator adapted to demodulate electrical signals according to a first modulation / demodulation protocol;

An electric signal modulator according to a second modulation / demodulation protocol differing from said first protocol, said second protocol being a spectral scattering protocol, said modulator modulating signals demodulated by said demodulator;

° means for converting said electric signals, modulated according to said spectral scattering protocol, called electric signals in the return channel, into radioelectric signals, adapted to be emitted by satellite;

- at least one box including a modulator adapted to modulate electric signals according to said first modulation / demodulation protocol;

- coaxial cable connecting the sending / receiving unit and the box adapted to:

° transferring said electrical signals in the downstream channel from said transmitting / receiving unit to said box;

° transferring electric signals obtained from said modulator according to said first protocol from said box to said transmitting / receiving unit.

[0014] By the invention, an installation is preferably used that uses two types of modulation / demodulation, for example, modulation / demodulation based on a protocol adapted for short-range wireless communication (ZigBee, KNX, or others) for the first modulation / demodulation, and modulation / demodulation based on a spectral scattering protocol, such as an asynchronous random band access protocol by SPREAD ALOHA modulation using interference suppression techniques (note that demodulation using interference suppression techniques is used in a satellite focus and will no longer be described in detail in the present application). As a small distance is meant a distance of less than 300 m, and preferably less than 100 m. The box is preferably a box located inside the property (e.g., in a flat), and the transmitting / receiving unit is preferably located outside or near the antenna. Thus, the transmitting / receiving unit acquires, via its demodulator, its own digital signal (included in the modulated signal in the box) and modulates this digital signal with its modulator. The fact that the return to digital signal takes place in an external transmitting / receiving unit makes it possible to eliminate noise and signal errors and use a low power amplifier to amplify the modulated signal that contains very little noise. via its demodulator, its own digital signal (contained in the modulated signal in the box) and modulates this digital signal with its modulator. The fact that the return to digital signal takes place in an external transmitting / receiving unit makes it possible to eliminate noise and signal errors and use a low power amplifier to amplify the modulated signal that contains very little noise. via its demodulator, its own digital signal (contained in the modulated signal in the box) and modulates this digital signal with its modulator. The fact that the return to digital signal takes place in an external transmitting / receiving unit makes it possible to eliminate noise and signal errors and use a low power amplifier to amplify the modulated signal that contains very little noise.

[0015] The installation uses a forwarding channel for transmitting signals to users, which may be a terrestrial channel (e.g., in the frequency band between 470 and 862 MHz) or satellite (e.g., Ku or Ka band), and a satellite return channel (bandwidth). frequencies, for example, between 1.5 and 5 GHz, i.e. S band frequencies, whereby the use of this frequency band is not limiting). It should be noted that the reverse frequency satellite channel frequency band is selected such that it is sufficiently spaced from the band used in the forward channel (e.g., S-band transmission and Ku-band reception) so that there is no need for a diplexer. ("Diplexer" in English) to avoid overlap (interference) of one channel with another.

[0016] There are many advantages of such an installation.

[0017] In the broadcast transmission channel, users use proven technology to transmit large-sized signals, such as television signals, and the satellite return channel allows the user in particular to interact with the transmission channel and send out relatively short messages, while the technique modulation is based on a spectral scattering protocol, such as an asynchronous protocol of random random access to band scattering by SPREAD ALOHA modulation. Such a protocol is, for example, described in document US 2010/0054131 (del Rio Herrero et al.).

Furthermore, the means necessary for modulation based on the spectral scattering protocol are installed only in the transmitting / receiving unit, and the user's (user's) box (s) is equipped (equipped) with a modulator, using a modulation technique, requiring preferably means, which the use is cheaper and simpler (modulation / demodulation adapted for wireless communication, such as in ZigBee or KNX technology) compared to modulation means based on the spectral scattering protocol. The advantage of such an installation is that it allows to have only one external sending / receiving unit and a plurality of boxes inside (e.g. in different apartments), the production cost of said boxes being relatively low. The cost of the transmitting / receiving unit can thus be distributed among multiple users. It should be noted that the use of modulation / demodulation adapted for wireless communication, such as ZigBee or KNX technology with coaxial cable, enables the use of this technology without losses on a much longer cable length than if the communication were wireless in the air. [0019] The system according to the invention allows its very easy (and without significant additional costs) adaptation to an existing installation, in that it is sufficient to add a sending / receiving unit (preferably outside the apartment) and a box (preferably inside the apartment) that are connected to an existing coaxial cable. In addition, the antenna broadcasting the satellite signals is an antenna (i.e. means to transmit to the satellite radioelectric signals with microwave frequencies) very cheap, omnidirectional or with low directivity (for example, antenna amplification is less than 10 dBi), and easy to install. Depending on the frequency used, the signal emitted by the antenna can be received by a satellite or a "ground" collector. It should be noted that it is possible to free itself from the use of this antenna in the case of a satellite forward channel using a parabolic reflector for return path transmission.

The low cost of the transmitting / receiving unit is also due to the fact that when using two different emission and reception bands (e.g., S-band emission and Ku-band reception) it is not necessary to use a diplexer to avoid overlapping one channel on the other. second.

[0021] It should further be noted that the system according to the invention is very developmental. Indeed, it is perfectly possible to start using the system in a very large area (for example, throughout the country), giving all feedback signals to the satellite, without having to develop any terrestrial component; starting from the moment when the satellite's performance is no longer sufficient, the zone or service zones to which most messages are sent are determined. Since then, instead of directly using the antenna - satellite connection, it is possible to predict the use of "terrestrial" collectors, i.e. ground reception stations, which serve as relays and enable reducing the satellite load. Signals of appropriate frequency, emitted by the terminals are then received by the collectors, instead of the satellite.

[0022] The broadcast channel of terrestrial or satellite broadcasting may be firmly integrated with the satellite return channel, since it may contain, in one of the multiplex signals broadcast, signaling information useful for the good operation of the installation. This information may have emission parameters to be used (frequency, data transfer rate - "symbol rate", code of dissipation), system load, security keys, as well as other installation instructions. The transmitting / receiving unit therefore contains a logic that is necessary to interpret information present in terrestrial or satellite broadcasting channels and to use it to control the signal emission. In addition, the transmitting / receiving unit can generate from a signal present in the forward channel,

The installation according to the invention is all the more unusual for a person skilled in the art in the case of a transmission channel in terrestrial transmission (hybrid installation), as it is difficult to imagine a satellite-to-earth hybrid system with a satellite return channel without consequent addition of equipment leading to exorbitant additional costs for the user. It is the use of the modulation defined for the communication between the sending / receiving unit and the boxes, the second modulation for the satellite emission, the cheap antenna, as well as only one cable connecting the boxes in individual apartments with an external sending / receiving unit makes the installation according to the invention attractive.

[0024] The transmitting / receiving installation according to the invention may also have one or more of the following features taken into account separately or in all possible technical combinations:

- said electric signal modulator according to the second modulation / demodulation protocol comprises means applying a spectrum scattering protocol operating according to an asynchronous random access protocol for spectrum scattering;

- said first modulation / demodulation protocol based on a protocol adapted for short-range wireless communication, such as the following protocols: ZigBee, KNX, WiFi, BlueTooth or WiMax;

- said first modulation / demodulation protocol based on a protocol adapted to a wired technology, e.g. Ethernet or communications via a CPL power line;

- said transmitting / receiving unit comprising means for extracting from the electrical signals in the forward channel, signaling information for setting the emission parameters and / or the time signal;

- said transmitting / receiving unit comprises a demodulator of said electrical signals in the forward channel, such as a demodulator adapted to demodulate signals, according to one of the following standards:

° DVB-T;

° DVB-T2;

° DVB-S;

° DVB-S2;

° DVB-SH;

- said transmitting / receiving unit and / or said box including means of wireless communication, such as WiFi, WiMax, BlueTooth, ZigBee or KNX means;

- said electrical signals in the return channel are modulated in the transmission frequency band, called the S-band, in particular in the band [1980 MHz; 2010 MHz];

- these measures adapted to receive electrical signals obtained as a result of processing radio-electric signals are adapted to receive terrestrial radio-electric signals with microwave frequencies in the UHF or VHF band;

- the aforementioned measures adapted to receive electric signals obtained as a result of processing of radioelectric signals are adapted to receive satellite radioelectric signals with microwave frequencies in the Ku band or in the Ka band;

- said transmitting / receiving unit comprising means for issuing to said satellite and / or receiving ground station said radioelectric signals adapted to be emitted by satellite;

- said installation includes a larger number of boxes exchanging signals with one transmitting / receiving unit.

[0025] The subject of the present invention is also a transmitting / receiving unit that can be incorporated into an installation according to the invention, said unit comprising:

- means adapted to receive electrical signals obtained as a result of processing of radioelectric signals received by terrestrial radio link or by satellite called electric signals in the forward channel;

- a demodulator adapted to demodulate electrical signals according to the first modulation / demodulation protocol;

an electric signal modulator according to a second modulation / demodulation protocol differing from said first protocol, said second protocol being a spectral scattering protocol, said modulator modulating signals demodulated by said demodulator;

- means for converting said electric signals, modulated according to said spectral scattering protocol, called electric signals in the return channel, into radioelectric signals adapted to be emitted by satellite.

[0026] It should be noted that even if the transmitting / receiving unit is mainly described as the only device that integrates all of the functions described above, it can also include the deployment of a larger number of separate devices performing these functions: it can also be considered that the emission means for satellites (e.g., antenna) were not directly integrated in the same device.

[0027] An object of the present invention is also a box adapted to be incorporated into an installation according to the invention comprising a modulator adapted to modulate electric signals according to said first modulation / demodulation protocol.

[0028] Other characteristics and advantages of the invention will emerge clearly from the description, which is given below as an explanatory title and has no restrictive character, with reference to the attached figure, which schematically shows an installation according to one embodiment of the invention.

[0029] Fig. 1 schematically illustrates a transmitting / receiving installation 1 according to a first embodiment of the invention.

The transceiver / receiver installation 1 is adapted to operate with a standard teletransmission radioelectric antenna 3 (hernia) (e.g., a ladder antenna located on the roof of a building or a dwelling), allowing reception of signals in the UHF or VHF band, including streams digital terrestrial television programs, encoded according to the DVB-T or DVB-T2 protocol.

[0031] Transmit / receive installation 1 includes:

- a transmitting / receiving unit 2 placed outside the house;

- coaxial cable 10;

- microwave coupler / uncoupling device 9 radioelectric signals;

- a series of boxes (two boxes 11 and 11 bis are shown here) intended to be placed inside the property (each box is, for example, inside the flat).

[0032] The teletransmission radioelectric antenna 3 receives the modulated signals according to the DVB-T or DVB-T2 standard, for example, in the UHF band (470-866 MHz band).

[0033] The transmitting / receiving unit 2 comprises:

- input means 4 adapted to receive terrestrial electrical signals received by the antenna 3 (the antenna and the input means 4 are, for example, connected by a coaxial cable 20);

- microwave coupler / uncoupling device 8 radioelectric signals;

- modem 7 operating according to a first modulation / demodulation;

- modulator 5 operating according to a second modulation / demodulation;

- an omnidirectional or near omnidirectional antenna (i.e. a low direction directivity antenna having, for example, antenna gain less than 10 dBi), adapted to convert electric signals in the transmission band S (e.g., in the band [1980 MHz - 2010 MHz]) for microwave radio signals and for transmitting these signals to satellite 100, or to collector 101 in the S-band;

- demodulator 6.

[0034] The modulator 5 operates, for example, according to an asynchronous random access protocol for band spreading by means of SPREAD ALOHA modulation, optimized so that the satellite focus can use interference suppressing means (such a protocol is described, for example, in US Patent Document 2010/0054131 (del Rio Herrero et al.));

The modem 7 comprises a modulator 22 and a demodulator 21 and is, as far as type is concerned, a modem operating in accordance with the FSK ("Frequency Shift Keying") protocol or with the MDF frequency shift modulation protocol, or with a derivative thereof Protocol; wherein the modem 7 is preferably a modem operating according to a protocol adapted for short-range wireless communications (e.g., less than 300 m in wireless operation), such as a ZigBee or KNX modem.

[0036] The demodulator 6 operates in accordance with the DVB-T standard (described in the ETSI EN 300 744 standard of "Digital Video Broadcasting (DVB);") or DVB-T2 (described in the ETSI standard). EN 302 755 «Digital Video Broadcasting (DVB); DVB-T2 standard extensions, such as DVB-T2-lite, described in« DVB; BlueBook A122 »).

[0037] Box 11 includes:

- microwave coupler / uncoupler 12 radioelectric signals;

- modem 14 operating according to the same protocol (first modulation / demodulation) as modem 7; the modem 14 is, for example, a ZigBee or KNX modem;

means 16 for WiFi, WiMax, BlueTooth, ZigBee or KNX wireless communication, with a local network, or wired communication of the Ethernet type or the like, with a local network; these means 16 allow receiving signals sent to the modem 14;

- USB 15 input / output connection, adapted to exchange signals with a digital television decoder 28, also called STB ("Set Top Box");

- a coupler 31 that interconnects modem 14, respectively, with an input / output 15 connection and with means 16 for wireless communication.

[0038] The box 11 bis is identical to the box 11.

[0039] The coaxial cable 10 connects the boxes 11 and 11 bis to the transmitting / receiving unit 2.

[0040] The coaxial cable 10 is split into two by passing through the microwave coupler / decoupler 9, such that it connects the transmission / reception unit 2 and the box 11 respectively by means of the extension 18 of the cable 10, and the sending / receiving unit 2 and the box 11 bis with the extension 19 of the cable 10. It should be noted that the microwave coupler / decoupler 9 is a device operating in two directions (i.e. it permits the passage of radio-electric signals entering and leaving). The same applies to other microwave couplers / disconnectors in the installation.

[0041] The operation of the installation 1 will be explained with reference to the exchange between the transmitting / receiving unit 2 and the box 11, it being assumed that the operation is also identical between the transmitting / receiving unit 2 and the box 11 bis.

The operating principle of the installation 1 according to the invention consists in using the receiving part (without transmitting) terrestrial radio link formed by the ladder antenna 3 and the input means 4 adapted to receive ground electrical signals received by the antenna 3 and the sending part in the S band.

[0043] The transmitting portion in the S band is a return channel that allows the establishment of interactive services (voting, downloading of content available when logging in, ordering new services, such as custom video) or M2M type services (home appliance control, supervision, parameter monitoring measured by the sensor) with a relatively limited and cheap addition of equipment to an existing installation. The omni-directional antenna 23 allows the transmission of signals in the S-band, either directly to the satellite 100, or assuming an increase in efficiency, to the ground-based collectors 101 (in this case, the antenna 10 may be somewhat directional so that the emission reaches the collector 101).

[0044] All signals are connected in one coaxial cable 10.

[0045] The ground signals, received by the antenna 3, and then by the input means 4, are transmitted by the microwave coupler / uncoupler 8 by means of a coaxial cable

10.

[0046] These signals are then acquired in the microwave coupler 12, before being transmitted to the STB 28 via a coaxial cable 17.

The signals to be emitted in the S-band are digital signals that are modulated by a ZigBee 14 modulator (i.e., first modulation / demodulation) of the box 11 to an intermediate frequency (e.g., 868 MHz or 2.4 GHz, given in pure pictorial). These reverse channel signals may themselves come from signals coming from other devices connected by wireless (via connection 16) or wired to the box 11.

[0048] The modulated ZigBee signals are transmitted via coaxial cable 18 through coupler / uncoupler 12, then via coaxial cable 10 through coupler / disengageer 9, which transmits signals to transmission / reception unit 2.

[0049] The coupler / decoupler 8 of the transmitting / receiving unit 2 transmits the modulated ZigBee signals to the demodulator 21 of the ZigBee 7 modem.

[0050] The demodulator 21 acquires digital signals from the modulated ZigBee signal. It should be noted that the demodulator 21 may use error correction means to eliminate noise typical of the analog signal transmitted via the cable.

As soon as the digital signals have been acquired, the latter are modulated by a modulator 5 operating according to a second modulation / demodulation according to the asynchronous multiple random band access protocol by means of SPREAD ALOHA modulation in the S frequency band [1980 MHz - 2010 MHz ]. The fact of obtaining digital information in a very "pure" form entails that the modulated signal contains little noise and requires little amplification. It should be noted that the use of a low power amplifier can nevertheless be considered to amplify the modulated signals to be transmitted in the S band to the satellite 100 or to the collector 101 via the antenna 23.

[0052] It should be noted that the selected intermediate frequency band (e.g., 868 MHz) has the advantage of being compatible with the standard concentric cable's transfer band and allows limiting losses on the coaxial cable without having to transpose frequencies in the transmitting / receiving unit. . In addition, the fact of using the UHF band separated from the 868 MHz frequency, avoids interference between signals transmitted using the same cable. It should be noted that the use of another intermediate frequency by the ZigBee 14 modulator, e.g., 430 MHz, in the UHF band, may require the frequency to be transposed in the box 11 so as to avoid interference on the cable 10 (e.g. using a local oscillator and a frequency mixer).

[0053] It should also be noted that various couplers / couplings may be provided with a filter to acquire only a usable portion of a given frequency.

[0054] The uplink receiving channel in the UHF band also makes it possible to obtain useful information. It may be, for example, the frequency or bandwidth that will be applied to the return channel in the S band. It may also be updates related to the modulation / demodulation used by the modulator 5. In other words, the terrestrial forward channel may be firmly integrated with the via a reverse satellite channel, since terrestrial multiplexed signals may contain signaling information useful for the good operation of the installation. This information may include emission and use parameters (frequency, data rate "symbol rate", code of dissipation), system load, security keys, as well as other instructions regarding the installed equipment.

[0055] To accomplish this, the transmitting / receiving unit 2 therefore comprises a logic that is necessary to interpret information in and on the terrestrial transmission channel in order to control the signal emission. The last point assumes that the transmitting / receiving unit includes a demodulator 6, operating according to the DVB-T standard, to extract signaling information used to determine the emission parameters in the reverse channel, present in the ground part of the electrical signals, this information being sent to 5. The demodulator 6 may also send to the modulator 5 (directly or by means of signal processing means that is not shown) a clock signal («clock») very stable (e.g., with a frequency error less than 1 ppm),

[0056] It should be noted that the external transmitting / receiving unit 2 comprises a power supply 29; this DC power supply can be sent directly via an outgoing channel via coaxial cable 10 (through the extraction means of units 2, not shown here). It is also possible to charge the battery of the PSU 29 via a panel or solar panels 30.

The power consumption of the transmitting / receiving unit 2 may be limited by powering the modulator (in this case with the built-in amplifier of the signals to be transmitted) only when the signal is to be emitted. To achieve this, the transmitting / receiving unit 2 comprises means for powering the modem 5 only after the demodulator 7 receives the broadcast signal. For all applications in which the use indicator ("duty cycle" in English) is reduced (for example, one message every minute), the implementation of such a solution allows you to not use energy during periods in which messages are not broadcast.

[0058] A second particularly interesting application of the installation according to the invention relates to the field of M2M. In this case, the return channel in the S band can be used to transmit information from a home-based device, such as an alarm system; thus, when the alarm system is activated, the signal is sent by the alarm system to the means of wireless communication 16 (e.g., measures based on ZigBee protocols) and the message indicative of the alarm being triggered is transmitted in the return channel in the S band.

[0059] According to one variant of the invention, it is also possible to use a satellite transmission channel as described in patent application WO 2011076791 filed by the applicant in place of the above-ground forward channel. In this case, the ladder antenna 3 and the input means 4 adapted to receive terrestrial electrical signals received by the antenna 3 are replaced by a parabolic reflector and a LNB («Low Noise Block») for receiving signals from the satellite, e.g. Ku band (10.7 GHz band - 12.75 GHz). The LNB block of the transmitting / receiving unit transforms the received microwave signals into electrical signals in an intermediate satellite band to send them to the box via a coaxial cable.

[0060] In this case, the demodulator 6, operating according to the DVB-T standard, becomes a demodulator operating, for example, according to the DVB-S2 standard (ETSI EN 302307 Digital Video Broadcasting (DVB); Second generation framing structure, channel coding and modulation; systems for Broadcasting, Interactive Services, News Gathering and other broadband satellite applications (DVB-S2)). According to this last embodiment, it is advantageously used to amplify the reflector for receiving microwave frequency signals in the Ku band for transmitting signals via the reverse path in the S band.

[0061] According to another embodiment of the invention, instead of using modems 7 and 14 operating according to a protocol adapted for short-range wireless communication (e.g., ZigBee or KNX), wired technology, such as Ethernet or CPL power line technology, may be used. In this case, modems 7 and 14 are replaced with CPL modems, and each box communicates with other devices inside the home via the mains. The CPL signals received by the box 11 are modulated by a CPL modulator with a frequency of, for example, in the range of 1 to 20 MHz and transmitted via a coaxial cable.

[0062] It should also be noted that the transmitting / receiving unit may have means for wireless communication or for transmission using the CPL power line to communicate with other devices, especially when coaxial cable transmission is not working.

[0063] The ladder antenna or parabolic reflector is preferably an antenna or collective reflector used together on the roof of the property and divided into multiple users, each of which is equipped with a cable television box.

[0064] Of course, the invention is not limited to the described embodiment.

[0065] Thus, the invention has been described in more detail for the case of its use in the S band, but it can also be used in the C band.