RADIO-TELEPHONE COMMUNICATION NETWORK.

Abstract

Telephone communication network comprising at least one central telephone station, at least one fixed transmission base connected to the central telephone station to provide a radio-telephone interface and to communicate with mobile stations via a radio link and at least one repeater station associated with a transmission base to provide an overall radio link with the transmission base and the mobile stations, the repeater station comprising in the direction of reception of signals from the mobile stations a series of channels (27) equipped with gain control devices (29) acting on variable gain amplifiers (30).

Description

The present invention relates to a network radio-telephone communication. We are familiar with radio communication networks- telephone system comprising a series of central telephone stations connected to a series of fixed transmission bases distributed across the territory to be covered by the network communication and each comprising a plurality of en- each assembly comprising a radio interface component telephone, a transmitter and a receiver for communication with mobile stations via a radio link. The main patent indicated that the installation of a transmission base involved a number of constraints, in particular the availability of a sufficiently high site for the installation of the antennas and a nearby room for the installation of the components constituting the transmission base. It was also emphasized that installing a transmission base on the roof of a building required the passage of telephone cables throughout the entire building, extended by a connection underground. In order to minimize problems with the installation of the transmission bases, it was proposed in the patent a main telephone communication network comprising at least one central telephone station, at least a fixed transmission base connected to the telephone exchange- that to ensure a radio-telephone and communication interface to connect with mobile stations via a radio link, and at least one repeater station associated with a transmission base to ensure an overall radio link with the transmission base and the mobile stations, the overall radio link being understood as a radio link transmitting the entire range of frequencies on which the various communications take place. According to one advantageous version, it was proposed a repeater station comprising a transmitting device- receiver for communication with the transmission base, this transmitter-receiver unit being connected to a transmission line sion of radio signals to mobile stations and to a radio signal reception line from the stations mobile stations, these two lines being connected to a common oscillator to ensure carrier frequency transposition between the communication from the repeater station with the transmission base and with the mobile stations. In this case, the transposition and its associated amplification are performed uniquely regardless of the number of channels processed by the repeater station. However, it turned out that in the case of a repeater station handling a multi-channel radio link, there is generally an extremely significant difference in dynamic level between the signals received from the mobile devices. important which, for treatment by a trans- organ unique position and amplification, requires power very important at the repeater station level. One aim of the present invention is to provide a repeater station having a structure that minimizes the power required to establish the link global radio. To achieve this goal, the invention proposes a telephone communication network in which the repeater station includes a transmitting component a transmitter-receiver for communicating with the transmission base, connected to a radio signal transmission line to the mobile stations and a radio signal reception line from the mobile stations; the transmission line comprising a series of channels, each including, depending on the direction of signal propagation, a frequency band selector, a carrier frequency transposition device, and an amplifier connected to a coupling device common to the channels, this coupling device being connected to a transmitting device; the receiving line comprising, depending on the direction of signal propagation, a receiving device, a preamplifier, a series of channels, each including a band selector, a gain control device associated with a variable-gain amplifier, and a carrier frequency transposition device connected to a coupling device common to the channels, itself connected to the transmitting-receiving organ; the transposition organs the carrier frequency of the transmitting and receiving lines being connected in pairs to the same local oscillator. Thus, the frequency range processed by each channel is reduced, and the radio signals from mobile stations are brought back by the gain control devices to approximately the same dynamic level with a lower power consumption. According to a preferred aspect of the invention, in the case where the gain control elements are too slow to ensure satisfactory transmission of signals having large and rapid dynamic ranges, a repeater station is provided, according to a preferred version of the invention, comprising a transceiver element for communicating with the transmission base, connected to a radio signal transmission line to the mobile stations and a radio signal reception line from the mobile stations; wherein the transmission line comprises, depending on the direction of signal propagation, a receiver and an associated modulating bit extraction element to a series of channels each containing a modulating organ lation, a carrier frequency transposition device and an amplifier connected to a coupling device common to the channels, this coupling device being connected to a transmitting device; the receiving line comprising, in a direction signal propagation, a receiving organ, a pre- amplifier, a series of channels each comprising a processing subset including a filtering and carrier frequency transposition stage, an amplification stage comprising fixed-gain amplification elements mounted in parallel, an analog-to-digital conversion stage, and a digital processing unit for generating weighted decision bits from signals digital signals from the analog- conversion organ logic-to-digital, this processing subset further comprising, between the analog-to-digital converter and the digital processing unit, means for storing signals at different gain levels, means for replaying these signals, and selecting a level of gain adapted to the digital processing unit, and trans- put into the digital signal processing unit memo- raised to this gain level; the channels being connected to a multiplexing device associated with a transmitter connected to the device transmitter; frequency transposition devices por- the transmitter and receiver line being connected in pairs to a common local oscillator, and the modulating bit extraction unit being connected to the transmitter and the processing subset of each channel of the receiver line to ensure a transfer control and synchronization information. Other features and advantages of the invention will still appear upon reading the description tion which follows from two particular non-limiting embodiments of the invention in connection with the accompanying figures, among which: Figure 1 is a schematic representation tick of a first embodiment of the invention, Figure 2 is a schematic representation. Figure 3 is a detailed representation of a second embodiment of the invention; Figure 4 is a detailed representation of a part of the device of Figure 2. of a part of the device in figure 3. With reference to Figure 1, the repeater station- trice 7 includes, as in the main patent, a component transceiver 8 for communicating with the trans- base mission, connected to a transmission line, usually designated as 11, of radio signals to mobile stations, and to a reception line, usually designated as 12, of radio signals from mobile stations, via the in- The transmission line 11 comprises a series of channels 21, only two of which are shown in Figure 1, each comprising, depending on the direction of signal propagation, a frequency band selector 22, a carrier frequency transposition device 23, and an amplifier 24 connected to a coupling device 25 common to the different channels, this coupling device 25 being connected to a transmitting device 4. The reception line 12 comprises, depending on the direction of signal propagation, a receiving device and a preamplifier 26 connected to a series of channels 27 of which only two have been shown in figure 1. Each channel 27 includes a band selector organ 28 connected to a gain control unit 29 associated with an amplifier variable gain amplifier 30 is itself connected to a frequency transposition organ carrier frequency 31 connected to a coupling element 32 common to the different channels 27, this coupling element being itself connected to the transmitter-receiver organ 8 by the inter- medial of the duplexing organ 10 The trans- organs Carrier frequency positions, 23 for transmission line 11 and 31 for reception line 12, are connected by pairs to the same local oscillator 13. With reference to figures 2 to 4, the station repeater 7 according to the preferred mode of implementation of the in- The device, like the one in Figure 1, comprises a transmitter-receiver unit 8 associated with a line transmission line 11 and a receiving line 12 via the inter- The transmission line 11 of a duplexer comprises, in the direction of signal propagation, a receiver 33 connected to a modulating bit extraction device 34 associated with a series of channels 35, only one of which has been illustrated in Figure 2. Each channel 35 comprises a modulation device 36, a carrier frequency transposition device 37, and an amplifier 38 connected to a coupling device 39 common to the different channels and itself connected to the emitting organ 4. The receiving line 12 comprises, according to a direction of signal propagation, a receiving element 5 connected to a preamplifier 40 associated with a series of 41 channels, only one of which has been shown in Figure 2. Each channel 41 includes a processing subset 42 connected to a multiplexing unit 43 common to the different channels, itself connected to a transmitter 44, which is connected to the transmitter-receiver unit 8 via the duplexing unit 10. The modulating bit extraction unit 34 is also connected by a line 45 to the processing subset 42 and to the transmitter 44 in order to transmit control and synchronization information to them. necessary for their operation. The processing subset 42 is represented This subset is shown in more detail in Figures 3 and 4. the treatment unit includes a filtering and transport component Carrier frequency configuration 102 comprising a first bandpass filter 104 (Figure 4) intended to select the corresponding frequency band of channel 41. The output of the bandpass filter 104 is connected to an input of a carrier frequency transposition device formed by a mixer having another input connected to a local oscillator 106, the second output of which is connected by a line 46 to the carrier frequency transposition device 37 of the transmission line 11. A filter 107 centered on the frequency of the local oscillator 106 and having a bandwidth equal to that of the signal to be processed is connected at the outlet of mixer 105. The outlet of the filtering and trans- The carrier frequency position 102 is connected to an amplification stage 108 comprising (see Figure 4) a first amplification stage including two fixed-gain amplifiers 109 connected in parallel. In the illustrated embodiment, one of the amplifiers 109 has a gain g adapted to the strongest signal expected to be received at the processing subset, while the other amplifier 109 has a gain g plus 40 dB. The amplifiers 109 are followed by mixers 110 having a first input connected to one of the amplifiers 109 and a second input connected to a local oscillator 111 whose function is to perform a frequency transposition to center the signal on the frequency Fb / 2, Fb being the bit frequency of the signal. The mixers 110 are followed by a filtering element 112 designed to eliminate residue. The output of each mixer 112 is connected in parallel to four output lines 113. For each group of output lines 113, one of the lines has no amplifier, the second line has an amplifier 114 with a gain of 10 dB, and a third line has an amplifier 115 with a gain of 20 dB and the fourth line includes an amplifier cateur 116 having a gain of 30 dB, which constitute a second amplification stage of the amplification unit 108 Thus, the output lines 113 have amplification levels fication which range between 0 and 70 d B of amplification relative to the input signal in the amplification unit 108. The output lines 113 of the amplifier unit Fication 108 are connected to the input of a sampler 117 comprising a series of connection means 118 mounted in parallel and controlled by a control element 119 to cyclically establish a connection between one of the lines 113 and a common analog-to-digital conversion element 120 In the example embodiment described where the conversion element is common to all amplification levels, the sampling frequency will be two Fb for each line 113, i.e. 16 Fb for the sampler in order to obtain a meaningful sampling of the received signals. The output of the conversion unit 120 is connected to an input of a storage means 121, another input of which is connected to the control unit 119 in order to assign to each sample received from the conversion unit 120 an address corresponding to the line 113 associated with the stored sample. Storage means 121 are connected to selection means of stored signals 122 which perform a reading of the set- sample selection from a stored packet for each amplification level and selection of the most suitable amplification level based on criteria introduced at the level selection methods, for example the average energy level gie or the number of skimmings. Furthermore, the storage means 121 and the stored signal selection means 122 are connected to a digital processing unit 123 so that, after determining the most suitable amplification level for the packet that has just been received, the stored signal selection means transmit to the unit digital processing information on the amplification level fication and simultaneously trigger the transfer from the storage means 121 to the digital processing unit 123 of all the collected samples at this level of amplification. Note that for each package, the amplification level selection is performed after memorization of all the bits of a packet. The selection- Therefore, selection is performed not only on the insignificant bits of a packet, but also on the significant bits, resulting in a very high-quality selection. Furthermore, since it is performed on each received packet, the selection is particularly well-suited even when the received signal level varies significantly. package to another. The digital processing unit 23 performs equalization of the received bits using conventional methods and delivers decoded bits in a weighted decision, which are transmitted to the multiplexing unit 43. It should be noted in this regard that the equalization operation is a partial processing operation that requires neither a very complex installation nor high power and can therefore be easily processed in a repeater station.

Claims

DEMANDS 1. Radio-telephone communication network comprising at least one central telephone station, at least one fixed transmission base connected to the station telephone exchange to provide a radio-telephone interface voice and communicate with mobile stations via a radio link, and at least one repeater station (7) associated with a transmission base to ensure an overall radio link with the transmission base and the mobile stations, characterized in that the repeating station- trice (7) includes a transmitter-receiver element (8) for communicating with the transmission base, connected to a transmission line (11) of radio signals to the mobile stations and a reception line (12) of radio signals from the mobile stations; the transmission line (11) comprising a series of channels (21) each comprising, according to a direction of signal propagation, a frequency band selector element (22), a carrier frequency transposition element (23) and an amplifier (24) connected to a coupling element (25) common to the channels, this coupling element being connected to a transmitting element (4);the receiving line (12) comprising, according to a direction of signal propagation, a receiving element (5), a preamplifier (26), a series of channels (27) each comprising a band selector element (28), a gain control element (29) associated with a variable gain amplifier (30) and a carrier frequency transposition element (31) connected to a coupling element (32) common to the channels, itself connected to the transmitter-receiver element (8); the carrier frequency transposition elements (23,31) of the transmitting line and the receiving line being connected in pairs to the same; local oscillator ( 13).

2. Radio-telephone communication network comprising at least one central telephone station, at least one fixed transmission base connected to the station telephone exchange to provide a radio-telephone interface phonic and communicate with mobile stations via a radio link, and at least one repeater station (7) associated with a transmission base to ensure an overall radio link with the transmission base and the mobile stations, characterized in that the repeater station (7) comprises a transmitter-receiver unit (8) for communicating with the transmission base, connected to a transmission line (11) of radio signals to the mobile stations and a reception line (12) of radio signals from the mobile stations; the transmission line (11) comprising, according to a direction of signal propagation, a receiver (33), a modulating bit extraction unit (34) associated with a series of channels (35) each comprising a modulation unit (36), a carrier frequency transposition unit (37) and an amplifier (38) connected to a coupling unit (39) common to the channels, this coupling unit being connected to a transmitting unit (4);the receiving line (12) comprising, according to a direction of signal propagation, a receiving element (5), a preamplifier (40), a series of channels (41) each comprising a processing subset (42) comprising a filtering and carrier frequency transposition element (102), an amplification element (108) comprising fixed gain amplification elements (109; 114, 115, 116) mounted in parallel, an analog-to-digital conversion element (120) and a digital processing unit (123) for handling bits; weighted decision-making based on digital signals in proof- nance of the analog-to-digital conversion unit; the processing subset further comprising, between the conversion unit (120) and the digital processing unit risk (123), means for storing signals at different gain levels, means (122) for replaying these signals, selecting a gain level suitable for the unit digital processing, and transmit to the processing unit digital processing of the stored signals at this gain level; the channels (41) being connected to a multiplexing device (43) associated with a transmitter (44) connected to the emitting organ- receiver (8); the carrier frequency transposition devices (37, 105) of the transmit and receive lines being connected in pairs to a common local oscillator (106) and the modulating bit extraction device (34) being connected to the transmitter (44) and the processing subset (42) of each channel of the receive line (12) to ensure control information transfer and synchronization.

3. Radio communication signal receiving device according to claim 2, characterized in that it comprises a common conversion element (120) with several amplification elements, this converter organ common sion being connected to the associated amplification elements by a connecting device (117) controlled to cyclically establish a connection between an amplification element and the common conversion organ ( 120). 4 Signal receiving device radio communication according to claim 2 or claim 3- cation 3, characterized in that the amplification unit (108) comprises several amplification stages in series in each of which amplification elements (109; 113, 114,115) are mounted in parallel according to a general structure pyramidal rale.