Millimeter-wave antenna system for in-vehicle mobile wireless communications

Abstract

An antenna system (100; 300) for in-vehicle mobile radio communications comprises at least one remote antenna module (2) connected to a central control unit (1) by a cable (3a; 3b). The remote antenna module (2) comprises a plurality of radiating elements (20), an RF front end (21), and a control interface (22). The central control unit (1) comprises a signal processor (10) and a control interface (12). The control interface (22) of the remote antenna module and the control interface (12) of the central control unit are suitably configured to transmit input / output data signals (S0, St) and control signals (S1, S3) via the cable (3a, 3b) to control the control interface (22) and RF front end (21) of the remote antenna module.

Description

[Technical Field]

[0001] The present invention relates to a mobile wireless communication system mounted on a vehicle using multiple millimeter wave antenna modules, and in particular to a method for a central unit to select and control, in real time, the antenna(s) having the best transmission and reception channel. [Background technology]

[0002] Currently, the 4G communication system is used for wireless data traffic. To meet the growing demand for wireless data traffic, a more advanced communication system known as 5G is being developed. The millimeter wave (mmW) band has been allocated for 5G communication systems to achieve higher data transmission speeds. However, in this frequency range, radio waves experience very high attenuation due to free-space propagation or the presence of obstacles. Therefore, to compensate for the loss and extend the radio wave transmission distance (coverage), it is necessary to increase the gain of the transmitting and receiving antennas. For this purpose, various techniques for adjusting multiple inputs and multiple outputs, such as beamforming (dynamically changing the transmitting and receiving beams) / beamsteering (dynamically addressing the transmitting and receiving beams) and multiple input-multiple output (MIMO), as well as coding and modulation techniques, can be utilized.

[0003] Since automobiles and other vehicles are usually made of metal or coated with metal, the vehicle itself blocks electromagnetic waves, especially those in the millimeter wave band. To solve this problem, vehicles must be equipped with multiple antennas to ensure reliable communication with radio base stations (BSs) regardless of the position of the BS relative to the vehicle. This improves the stability and usability of mobile communication systems.

[0004] Patent Documents 1 and 2 disclose millimeter-wave radar antennas for vehicles that are intended to detect obstacles. However, in this case, the radar does not need to communicate with a wireless base station (BS), and all radar antennas simultaneously detect obstacles within their respective visible ranges, so there is no need to select the radar antenna to use.

[0005] Devices that are typically much smaller than vehicles, such as mobile phones (smartphones), handheld devices (tablets), and portable electronic computers (laptops), use multiple antennas installed in different locations, from which the one or more antennas with the best channel quality are selected.

[0006] Patent Documents 3 and 4 disclose sensors, such as a six-axis sensor or a touch sensor (a sensor utilizing a capacitive sensor or other technology), that are mounted on a device and select an antenna. However, in these applications, the distance between the control unit and the selected / controlled antenna is short (on the order of a few centimeters). Therefore, communication with the antenna on a single electronic board is achieved by a very simple dedicated circuit and signal.

[0007] On the other hand, in the case of a vehicle, the length of the connecting cable between the central control unit and the remote antenna module is long (typically more than 2 meters) which requires different solutions in communication and antenna selection.

[0008] Patent Document 5 discloses a conventional vehicle antenna system comprising multiple antenna modules. Each module is equipped with only one conventional antenna, not a millimeter-wave antenna. Because the module only has one antenna, it is clear that the module does not have an RF front end capable of beamforming or beamsteering to change the direction of the antenna beam. Because the direction cannot be changed, the high path attenuation that occurs in millimeter-wave signals, which does not occur in low-frequency bands, reduces the antenna gain to a level that does not ensure proper communication connection. This antenna system uses single-phase and single-gain remote control for each module. The module does not have a beamforming RF front end that can simultaneously control the phase and gain of multiple antennas within the module. Because this antenna system operates at low frequencies, it does not require frequency conversion, as is required for millimeter-wave signals, when transmitting analog signals remotely. The system performs up-down conversion at an intermediate frequency (lower than the carrier frequency) for partial modulation / demodulation purposes. This reduces the required transmission and reception bandwidth so that it does not exceed the signal loss due to very high frequencies. This document discloses phase and amplitude variations between different antenna modules mounted on a vehicle, but does not mention beamforming or phase and amplitude variations of multiple antennas within one antenna module.

[0009] Patent Document 6 discloses a millimeter-wave antenna system based on timing of antenna selection. Individual antennas do not have the ability to change beamforming, and therefore no control over the antenna modules is required. Such a system provides switching between available antennas without a front-end capable of performing beam control, phasing, and beamforming for each individual antenna. Although mentioned, beamforming is not confirmed in the description of how beamforming is remotely controlled by a central controller. The antenna modules are located close to each other, easily selectable by switches (including mechanical switches), and close to the controller, which controls the modules very simply through direct digital connections. Therefore, Patent Document 6 does not address the issue of establishing control communication from a central location when remotely operating modules connected via coaxial or digital cables (e.g., Ethernet).

[0010] Patent Document 7 discloses an in-vehicle non-millimeter wave antenna system.

[0011] Patent document 8 discloses an in-vehicle digital antenna system. The system does not include a millimeter-wave antenna, a module with an antenna array, or an RF front end capable of performing beamforming between the antennas of the module. This document describes an analog control circuit for the antenna in an analog-to-digital converter, which can be located remotely from the antenna array, i.e., via an analog connection. This solution cannot be applied to millimeter waves, as excessive losses between the antenna structure and the amplifier in the analog-to-digital converter may significantly degrade the performance of the mmW system. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] U.S. Patent No. 5,767,793 [Patent Document 2] U.S. Patent No. 6,034,641 [Patent Document 3] International Publication No. 2019 / 156468 [Patent Document 4] US Patent Application Publication No. 2020 / 0044314 [Patent Document 5] US Patent Application Publication No. 2018 / 269915 [Patent Document 6] US Patent Application Publication No. 2018 / 288763 [Patent Document 7] US Patent Application Publication No. 2006 / 172712 [Patent Document 8] US Patent Application Publication No. 2019 / 393883 Summary of the Invention [Problem to be solved by the invention]

[0013] The object of the present invention is to overcome the drawbacks of the prior art by providing an antenna system for vehicular wireless communication that can select and control, in real time, the antenna(s) having the best transmit / receive channel conditions.

[0014] A further object is to provide an antenna system that is efficient, effective, reliable and easy to install. [Means for solving the problem]

[0015] These objects are achieved by the features of the invention as defined in the independent claims.

[0016] Advantageous embodiments of the invention are set out in the dependent claims.

[0017] The present invention relates to an in-vehicle antenna system for 5G communication and a method for realizing the antenna system, which supports higher data communication speeds compared to 4G systems. Based on 5G communication standards and related technologies, the antenna system of the present invention can be applied to different types of vehicles (e.g., automobiles, commercial vehicles, vans, trucks, trains, motorcycles, tractors, etc.).

[0018] The antenna system according to the present invention comprises at least one antenna module, each of which comprises a plurality of radiating elements operating in the millimeter wave band. The antenna modules are located at a distance from the center. The radiating elements have a tunable beam. Each antenna module has an RF front end capable of performing beamforming on the radiating elements of the module. The antenna modules are included in the module communication and control system described in this patent application, allowing them to be mounted in a vehicle at a distance from the central control.

[0019] The central part can select in real time at least one radiating element having the best transmit and receive channel.

[0020] In this way, the selected radiating element can transmit and receive signals with high accuracy based on sensing the quality of the signal received from the central portion. [Brief explanation of the drawings]

[0021] Further features of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, which are given by way of example only and are not intended to be limiting. [Figure 1] FIG. 1 is a schematic diagram of an antenna system according to the present invention, showing a central control unit connected to remote antenna modules located in various parts of a vehicle. [Figure 2] FIG. 2 shows in four block diagrams a possible structure of a remote antenna module of an antenna system according to the invention. [Figure 2A]FIG. 2A shows a block diagram of the central control unit of the antenna system according to the present invention. [Figure 3] FIG. 3 is a block diagram showing an antenna system according to the present invention, where the remote antenna modules and the central control unit are connected via a coaxial cable. [Figure 3A] FIG. 3A illustrates the signal direction managed by the antenna system of the present invention in the block diagram of FIG. [Figure 4] FIG. 4 is a block diagram illustrating an antenna system according to the present invention where the remote antenna modules and the central control unit are connected via a high speed digital cable. [Figure 4A] FIG. 4A illustrates the signal direction managed by the antenna system of the present invention in the block diagram of FIG. [Figure 5] FIG. 5 is a block diagram showing the minimum configuration in the case of a single millimeter wave radiating element. [Figure 6] FIG. 6 is a detailed block diagram of the controller of the system of FIG. [Figure 7] FIG. 7 is a block diagram showing in detail the control device of the central control unit of FIG. [Figure 7A] 7A is a block diagram showing a modification of the control device of the central control unit of FIG. 7; [Figure 8] FIG. 8 is a block diagram showing details of the control devices of the central unit and the remote antenna when transmitting data from the central unit to the remote antenna. [Figure 9] FIG. 9 is one of two block diagrams showing two possible configurations for the connection from the remote antenna to the central location in the case of digital transmission. [Figure 10] FIG. 10 is one of two block diagrams showing two possible configurations for the connection from the remote antenna to the central location in the case of digital transmission. DETAILED DESCRIPTION OF THE INVENTION

[0022] Referring now to the drawings, an antenna system according to the present invention is disclosed, and is generally designated 100.

[0023] Referring to Figure 1, the system 100 comprises a central control unit 1 connected to a number of remote antenna modules 2. The remote antenna modules 2 are located at various locations on the vehicle 200 and are connected to the central control unit 1 via coaxial or digital cables.

[0024] Since the system (100) is mounted on a vehicle (200), there is a direction (upstream) of signals transmitted from the system (100) to a wireless base station and a direction (downstream) of signals transmitted from the wireless base station to the system (100).

[0025] To increase the available bandwidth for large data transmissions, future mobile communication technologies, commonly known as 5G (an evolution of LTE via the 3GPP® body), enable the use of millimeter wave bands. Specifically, the FR2 band covers the range from 24.25 GHz to 52.6 GHz. At these frequencies, the path attenuation of millimeter waves in free space is very high.

[0026] To this end, the remote antenna module (2) comprises a dynamically addressable, narrow beam, high gain antenna utilizing specific techniques such as beam steering and / or beam forming.

[0027] Furthermore, millimeter wave propagation is virtually impossible to overcome obstacles, especially those made of metallic materials. For this reason, vehicle installations of remote antenna modules (2) in these frequency bands have been extensively studied and analyzed to identify optimal antenna locations where the line of sight (LOS) of each antenna is not obstructed by the bodywork and other components of the vehicle structure. In all cases, installations have been studied and optimized on a vehicle-by-vehicle basis to maximize performance and obtain maximum horizontal coverage.

[0028] The remote antenna module 2 may utilize antennas with different radiation characteristics, including limited horizontal antennas 2' located at the front, rear, and sides of the vehicle body (e.g., in the side mirrors) or integrated into the vehicle's headlights or bumpers, and possibly an all-horizontal antenna 2'' located in a location with a wide horizontal line of sight, such as the center of the vehicle's roof.

[0029] Referring to Figure 2, the remote antenna module (2) may comprise different types of antenna modules (2a, 2b). Each antenna module: a plurality of radiating elements (20) suitable for transmitting and receiving millimeter wave signals; - an RF front end (21) comprising circuitry for controlling the signals transmitted and received by the radiating elements and the beam steering / beam forming functions of the radiating elements (20); - a control interface (22) connecting the antenna module (2) to an electrical cable (3), either a coaxial or digital cable; Equipped with.

[0030] Advantageously, the radiating elements 20 of each module are arranged in a row, and the radiating elements 20 have a variable beam.

[0031] The antenna modules (2a, 2b) comprise a number of radiating elements (20) operable to vary the size and phase of the radiated beam, in which case the RF front end (21) is complex as it must be capable of beamforming / beamsteering.

[0032] The antenna module (2a) has an RF front end (21) that performs analog type beamforming / beamsteering, while the antenna module (2b) has an RF front end (21) that performs digital type beamforming / beamsteering.

[0033] Furthermore, the remote antenna module (2) may comprise an antenna module with an RF front end that performs hybrid beamforming / beamsteering in a mixed digital / analog manner.

[0034] Referring to Figure 2A, the central control unit (1) comprises a signal processor (10), for example a modem connected to a control interface (12) that connects the central control unit (1) to the electrical cable (3).

[0035] Due to the distance between the remote antenna module (2) and the central control unit (1), measures must be taken in the control interfaces (12, 22) of the central control unit (1) and the remote antenna module (2), in particular to configure the control interfaces (12, 22) so that input / output data signals and control signals suitable for controlling the control interface (22) and RF front end (21) of the remote antenna module can be transmitted via the electrical cable (3).

[0036] Figure 3 shows an antenna system (100) in which the connection between the remote antenna module (2) and the central control unit (1) is made via a coaxial cable (3a).

[0037] The central control unit (1) comprises a signal processor (10) such as a modem, and a control interface (12). The control interface (12) is connected to the signal processor (10) and a coaxial cable (3a) connected to the remote antenna module (2).

[0038] The remote antenna module (2) a plurality of radiating elements (20) of the millimeter wave type with variable beams; an RF front end (21) capable of performing beamforming between the radiating elements; - a control interface (22), Equipped with.

[0039] The control interface (22) comprises a frequency converter (23) and a control device (24).

[0040] The frequency converter (23) is connected to the RF front end (21) and to the control unit (24).

[0041] The frequency converter (23) allows the transmission of the input data signal (S0) (Fig. 3A) received from the antenna module via a coaxial cable (3a), which in fact can be very long (more than 2 meters), resulting in significant attenuation for signals in the millimeter wave frequency range, while attenuation is much lower for signals at intermediate frequencies (IF) of several GHz.

[0042] Furthermore, the frequency converter (23) converts the frequency of the output data signal (St) (FIG. 3A) transmitted by the antenna module.

[0043] Therefore, the frequency converter (23) converts the input data signal (S0) (FIG. 3A) of millimeter wave frequency received from the radiating element (20) into a data signal of a first intermediate frequency (IF1) configured between 1 GHz and 6 GHz depending on the signal band, and converts the output data signal (St) of the first intermediate frequency (IF1) or a different IF in the same frequency band received from the signal processor (10) into a data signal of millimeter wave frequency, which is then transmitted from the radiating element (20).

[0044] In addition to the input / output data signals (S0, St) to / from the frequency converter (23), control signals (S1, S2) from the central control signal processor (10) are also transmitted over the same coaxial cable (3a) to control the frequency converter (23) and the RF front end (21), respectively. The control signals (S1, S2) consist of low complexity signals and high complexity signals.

[0045] As shown in Fig. 5, a low-complexity signal is used to select a power amplifier (PA) for transmission and a low-noise amplifier (LNA) for reception.

[0046] On the other hand, in the case of antenna module (2a), high complexity signals are used to control an RF front end (21) capable of performing analog beamforming, and in the case of antenna module (2b), high complexity signals are used to control an RF front end (21) capable of performing digital beamforming.

[0047] In analog beamforming, high complexity control signals are used to control a network of phase shifters and power amplifiers (PAs) or low noise amplifiers (LNAs) that are essential for the analog beamforming function.

[0048] In the case of digital beamforming, high complexity control signals are used to control the digital beamforming stage, which typically consists of controllable phase shifters, amplitude (weight) control of the signals from each sub-antenna in the array, frequency converters, D / A and A / D converters, clock control, adaptive filters, etc.

[0049] The control interface (12) of the central control unit (1) comprises a control device (14) which communicates with a control device (24) provided in the control interface (22) of the remote antenna module (2) so that the control signals (S1, S2) are transmitted on the same coaxial cable (3a) as well as the input / output data signals (S0, St) converted to a first intermediate frequency (IF1).

[0050] The control device (14) of the central control unit comprises an UP-type frequency converter. The frequency converter is capable of converting the control signals (S1, S2) to a second intermediate frequency (IF2) different from the first intermediate frequency (IF1) used to transmit the data signals (S0, St). In the following description, the second intermediate frequency (IF2) is assumed to have a frequency range of 0.1 GHz to 1 GHz. This prevents interference between the input / output data signals (S0, St) and the control signals (S1, S2).

[0051] The control device (14) of the central control unit (1) includes a transceiver (41) that converts the control signal from the signal processor (10) to a second intermediate frequency IF2.

[0052] The control device 24 of the antenna module 2 is a DOWN frequency converter suitable for converting the control signals (S1, S2) from the second intermediate frequency (IF2) to a lower frequency, thereby controlling the frequency converter 23 and the RF front end 21. Furthermore, the control device 24 of the antenna module decodes the control signals (S1, S2) and handles the frequency converter 23 and the RF front end 21 accordingly. For this purpose, the control device 24 of the antenna module comprises a transceiver for converting the signals from the second intermediate frequency IF2 and a logic device such as a microcontroller, ASIC, FPGA, etc.

[0053] Furthermore, the remote antenna module 2 is powered via the same coaxial cable 3a used for data and control signal communication. To this end, the central control unit 1 and the remote antenna module 2 each have a power supply block 15, 25 that are in communication with each other via the coaxial cable 3a. The antenna module power supply block 25 can receive direct current (DC) power from the coaxial cable 3a without interfering with the high-frequency signals S0, S1, S2 traveling at intermediate frequencies IF1 and IF2 on the coaxial cable.

[0054] The control interface 12 of the central control unit 1 includes a plurality of DA / AD converters 16, each connected to a respective one of the remote antenna modules 2. Each DA / AD converter assembly 16 includes a digital-to-analog (DA) converter and an analog-to-digital (AD) converter.

[0055] Since the system 100 includes multiple remote antenna modules 2, it is possible to select one remote antenna module at a time or combine signals received from multiple remote antenna modules in digital or analog fashion, i.e., by antenna array, diversity, or various MIMO techniques (multiple amplitude and / or phase mixing, performed analog or digitally via a DSP). In the simplest case, antenna selection is performed by detecting the signal level (RSSI) of each antenna and selecting the antenna with the apparently greatest signal level (at maximum power).

[0056] Referring to FIG. 3A, upon reception, the input data signal (S0) obtained by the radiating element (20) is to be transmitted to the signal processor (10). To this end, the radiating element (20) receives a millimeter-wave input data signal (S0) that is amplified and routed to the correct path by the RF front end (21). The input data signal (S0) is transmitted to the frequency converter (23), which converts it to a first intermediate frequency (IF1) and introduces it onto the coaxial cable (3a), which transmits the input data signal (S0) to an A / D converter in the converter unit (16) of the central control. The A / D converter digitizes the input data signal (S0) and transmits it to the signal processor (10). It is clear that the converter (16) must be capable of sampling the input data signal (S0) at the first intermediate frequency.

[0057] During transmission, the output data signal (St) from the signal processor (10) is sent to the radiating element (20) for transmission through a medium. To this end, the signal processor (10) outputs the output data signal (St) in digital form. The converter unit (16) converts the output data signal (St) from digital to analog at a first intermediate frequency (IF1). It is clear that the converter unit (16) must have a digital-to-analog converter capable of performing conversion at the first intermediate frequency (IF1). The output data signal (St) at the first intermediate frequency (IF1) is transmitted via the coaxial cable (3a) to the frequency converter (23) of the remote antenna module (2), which converts it to a millimeter-wave frequency. The output data signal (St) at the millimeter-wave frequency is amplified and routed by the RF front end and transmitted to the medium via the radiating element (20).

[0058] The control signals (S1, S2) are generated by the signal processor (10) and sent to the central control unit (14), which converts the control signals to a second intermediate frequency (IF2) and introduces them into the coaxial cable (3a). The control signals (S1, S2) at the second intermediate frequency (IF2) reach the remote antenna module control unit (24), where they are converted to a lower frequency suitable for controlling the frequency converter (23) and the RF front end (21), respectively.

[0059] A power supply signal (A) is sent via coaxial cable (3a) from power supply block (15) to power supply block (25), which provides power to all active devices of the remote antenna module (2).

[0060] The power supply block 25 of the remote antenna module 2 transmits a diagnostic signal S4 indicating the status of the power supply block 25 to the control device 24. The control device 24 converts the diagnostic signal S4 to a second intermediate frequency IF2. In this case, the control device 24 must have an UP converter to convert the diagnostic signal S4 to the second intermediate frequency IF2. The diagnostic signal S4 at the second intermediate frequency IF2 is transmitted via the coaxial cable 3a to the control device 14 of the central control unit 1, where it is converted to a lower frequency and sent to the signal processor 10, which detects abnormalities in the power supply. Therefore, the control device 14 of the central control unit must have a DOWN frequency converter to lower the frequency of the diagnostic signal S4.

[0061] The control signals propagating from the central control unit (1) to the remote antenna module (2) include a power control signal (S5) that should reach the power supply block (25) of the remote antenna module. The power control signal (S5) propagates from the control unit (24) to the power supply block (25) following the same path as the control signals (S1, S2).

[0062] Referring to FIG. 6, the central control unit 14 includes a logic unit 40 that receives the control signals S1, S2, and S5 from the signal processor 10. The logic unit 40 performs encapsulation on the control signals S1, S2, and S5 and transmits the encapsulated signal C3 to a transceiver 41, which converts the encapsulated signal C3 to a second intermediate frequency IF2. The encapsulated signal C3 at the second intermediate frequency IF2 passes through a low-pass filter 42 suitable for blocking the first intermediate frequency IF1 present on the coaxial cable 3a and is transmitted to a multiplexer 43, where it is mixed with the output data signal St at the first intermediate frequency IF1. Optionally, the central control unit 14 may include a high-pass filter 44 suitable for blocking the second intermediate frequency IF2 present on the coaxial cable 3a before reaching the converter unit 16.

[0063] A mixed signal (M) containing the encapsulated signal (C3) and the output data signal (St) is transmitted from the multiplexer 43. The mixed signal is transmitted over the coaxial cable 3a and reaches the splitter 50 provided in the control unit 24 of the remote antenna module.

[0064] The demultiplexer (50) demultiplexes the encapsulated signal (C3) at the second intermediate frequency (IF2) from the output data signal (St) at the first intermediate frequency. The encapsulated signal (C3) at the second intermediate frequency (IF2) from the demultiplexer (50) passes through a low-pass filter (52) that blocks the first intermediate frequency (IF1) and reaches a transceiver (53) in the antenna module control device. The transceiver (53) converts the encapsulated signal (C3) back to baseband and sends it to a logic device (54) that decapsulates the control signals (S1, S2, S5).

[0065] Optionally, the remote antenna module control unit (24) may include a high pass filter (51) at the output of the splitter (50) to block the second intermediate frequency IF2.

[0066] 7, when there are multiple remote antenna modules 2, the encapsulated signal C3 at the second intermediate frequency IF2 from the only transceiver 41 in the central control unit is mixed with the output data signal St at the first intermediate frequency IF1 from each DA converter in the converter unit 16, and the mixed signal M is transmitted via the respective coaxial cables 3a connected to the respective antennas. In such a case, a number of low-pass filters 42 and multiplexers 43 may be provided, the number of which corresponds to the number of antennas 2.

[0067] 7A shows a central control unit (14) having a number of transceivers (41) equal to the number of antennas (2). Each transceiver (41) outputs an encapsulated signal (C3) at a second intermediate frequency (IF2) mixed with an output data signal (St) at a first intermediate frequency (IF1) from each DA converter of the converter unit (16).

[0068] 4 shows a second embodiment of an antenna system (300) based on signal propagation over a digital cable (3b), such as an Ethernet cable. Each remote antenna module (2) comprises at least one radiating element (20), an RF front end (21), and a control interface (22).

[0069] The control interface (22) includes a frequency converter (23), a DA / AD conversion unit (26), and a control device (124).

[0070] The DA / AD conversion unit (26) includes a digital-to-analog (DA) converter and an analog-to-digital (AD) converter suitable for converting analog signals into digital signals and digital signals into analog signals.

[0071] The central control unit (1) comprises a signal processor (10) and a control interface (12) comprising a control unit (114).

[0072] The antenna module control device 124 also preferably includes in the input data signal S0 a diagnostic signal S4 indicating the status of the control device 124. The central control device 114 also preferably includes in the output data signal St control signals S1, S2, S3 used to control the frequency converter 23, the RF front end 21, and the DA / AD converter.

[0073] The antenna module control unit 124 can separate the output data signal (St) from the control signals (S1, S2, S3). The central control unit control unit 114 can separate the input data signal (S0) from the diagnostic signal (S4).

[0074] For this purpose, the antenna module control device (124) comprises a digital transmission control device, a serializer / deserializer capable of encapsulating / deencapsulating digital signals, and a computing unit (e.g., a microcontroller, ASIC, or FPGA) that manages the antenna module device.

[0075] The control unit (114) of the central control unit includes a digital transmission control unit and a decapsulation-capable serializer / deserializer.

[0076] The input data signal (S0), output data signal (St), control signals (S1, S2, S3) and diagnostic signal (S4) are transmitted and received from the remote antenna module (2) to the central control unit (1) via digital cable (3b) and direct communication between the two control units (114, 124) of the remote antenna module and the central control unit.

[0077] The central control unit (114) is directly connected to the signal processor (10).

[0078] When the antenna module (2) is connected to the central control unit via the digital cable (3b), the DC power supply may be performed by a part of the support part of the digital cable (3b), which makes the power supply block (25, 15) shown in Figure 3 unnecessary.

[0079] Referring to Figure 4A, during reception, the input data signal (S0) acquired by the radiating element (20) is transmitted to the signal processor (10). To this end, the input data signal (S0) at millimeter frequencies is acquired by the radiating element (20) and transmitted to the RF front end (21) for amplification and routing. The input data signal (S0) is converted from millimeter frequencies to an intermediate frequency (IF1) between 0.1 GHz and 6 GHz by the frequency converter (23). The input data signal (S0) is then digitized by the AD converter of the converter unit (26).

[0080] The control device (124) encapsulates the input data signal (S0) together with the diagnostic signal (S4) in a digital communication protocol, thereby obtaining an encapsulated signal (C1).

[0081] The control unit 124 transmits the digitally encapsulated signal C1 (comprising the input data signal S0 and the diagnostic signal S4) over the digital cable 3b. The digitally encapsulated signal C1 then reaches the central control unit 114, where it is de-encapsulated to obtain the input data signal S0 for transmission to the signal processor 10.

[0082] During transmission, the output data signal (St) from the signal processor (10) is sent to the radiating element (20) for transmission over a medium. To this end, the signal processor (10) outputs the output data signal (St) in digital form. The central control unit (114) encapsulates the output data signal (St) with control signals (S1, S2, S3) to obtain an encapsulated signal (C2) for transmission over the digital cable (3b). The encapsulated signal (C2) is received by the remote antenna module control unit (124) and de-encapsulated to obtain the digital output data signal (St). The digital output data signal (St) is sent to the digital-to-analog converter of the converter unit (26) and converted to analog. The analog output data signal (St) is converted to millimeter frequency by the frequency converter (23). The millimeter-wave frequency output data signal (St) is amplified and routed by the RF front end (21) and transmitted over the medium by the radiating element (20).

[0083] The control signals (S1, S2, S3) are generated by the digital signal processor 10 and sent to the central control unit 114, where they are encapsulated with the output data signal (St) to obtain the encapsulated signal (C2) that is transmitted over the digital cable 3b. The encapsulated signal (C2) (including the output data signal (St) and the control signals (S1, S2, S3)) is received by the remote antenna module control unit 124, which decapsulates the signal to obtain the digital control signals (S1, S2, S3) that control the frequency converter 23, the RF front end 21, and the DA / AD converter 26, respectively.

[0084] A power signal (A) travels from the central control unit (114) to the remote antenna module control units (124), thereby providing power to all active devices in the remote antenna modules.

[0085] The diagnostic signal S4 is used to notify the signal processor 10 of the status of the control device 124 and the overall status of the remote antenna module. The diagnostic signal S4 is a digital signal that is encapsulated by the remote antenna module's control device 124 together with the input data signal S0 to obtain an encapsulated signal C1. The encapsulated signal C1 is then transmitted via the digital cable 3b and received by the central control device 114, where it is de-encapsulated to obtain the digital diagnostic signal S4, which is then transmitted to the signal processor 10. This allows the status of the control device 124 and the overall status of the remote antenna module to be detected.

[0086] FIG. 8 shows a block diagram of a digital transmission from the control unit (114) of the central control unit (1) to the control unit (124) of the remote antenna module (2).

[0087] The control device (114) of the central control unit (1) includes an encoding / decoding logic circuit (115), a serializer / deserializer (116), a clock recovery / phase-locked loop (PLL) circuit (117), and a line driver (118). The central control unit (1) includes a clock generator (119) connected to the PLL (117), so that the PLL can generate a clock signal (Sc) that is sent to the serializer (116).

[0088] The control unit (124) of the antenna module (2) comprises a line driver (128), a deserializer / serializer (126), a clock recovery / PLL unit (127), and a decoding / encoding logic circuit (125).

[0089] The encoding logic (115) of the central control unit receives the output data signal (St) and control signals (S1, S2, S3) from the signal processor (10), processes and encodes them. The encoded signals are sent to a serializer (116), where they are queued in a single high-speed data stream along with a clock signal (Sc) that serves as a synchronous time reference.

[0090] The standby signals (St, S1, S2, S3) are transmitted by the line driver (118) via the digital cable (3b).

[0091] The high-speed signal stream is received by a line driver 128 in the remote antenna module controller, where it may be further amplified. A clock signal (Sc) is then recovered by a clock recovery unit 127 and sent to a deserializer 126, which deserializes the signal stream. The deserialized signal stream is sent to a decoding logic circuit 125, where the output data signal (St) and control signals (S1, S2, S3) are de-encapsulated and routed onto the associated buses.

[0092] The input data signal (S0) and other control signals may propagate in the opposite direction to that shown in FIG. 8, i.e., from the remote antenna module controller (124) to the central control controller (114), and from the remote antenna module controller (124) to the controller (114), by reversing the operation of each device.

[0093] In this case, the decoding / encoding logic (125) acts as the encoding logic, the deserializer / serializer (126) acts as the serializer, the line driver (128) introduces signals onto the digital cable (3b), the line driver (118) receives signals from the digital cable (3b), the serializer / deserializer (116) acts as the deserializer, and the decoding / encoding logic (115) acts as the decoder.

[0094] Referring to Figure 9, all remote antenna modules 2 receive signals (St, S1, S2, S3, Sc) via respective digital cables 3b. The digital cables are connected to a shared single data bus (B) extending from line drivers 118 in the central control unit 114. Similarly, all remote antenna modules 2 transmit input data signals (S0) and any control signals via their respective digital cables 3b on the shared data bus (B).

[0095] In this case, the various signals propagating on the shared data bus (B) have addressing (shared bandwidth), so that the transmission protocol headers inserted by the respective control devices (114, 124) encapsulating the signals they send on the shared data bus (B) allow for precise identification of the sender / receiver.

[0096] Referring to Figure 10, all remote antenna modules 2 transmit and receive signals via their respective digital cables 3b, which are connected to their respective dedicated data buses B1,...,Bn extending from line drivers 118 of the central control unit 114.

[0097] In this case, each remote antenna module (2) has its own dedicated data bus (dedicated bandwidth), which eliminates ambiguity between sender and receiver and avoids bandwidth limitations imposed by digital communication protocols for ultra-high speed data signals.

[0098] Using CST and HFSS, the applicant performed laboratory simulations of the antenna system (100; 300) integrated with vehicle components to test its performance. The beamforming performance of the RF front end (21) was measured and monitored by a dedicated IC, and the RF front end (21) was controlled by a specially programmed FPGA.

[0099] Simulations have shown that beamforming of the radiating elements of the module is essential and that such beamforming can be controlled by control signals (S2) from the central control unit (1).

Claims

1. At least one remote antenna module (2) connected to a central control unit (1) by a cable (3a), The remote antenna module (2) at least one radiating element (20) suitable for transmitting and receiving input / output data signals (S0, St); an RF front end (21) suitable for amplifying, phase controlling and routing said input / output data signals (S0, St); a control interface (22) connected to said RF front end (21) and to said cable (3a); Equipped with The central control unit (1) a signal processor (10), a control interface (12) connected to said signal processor (10) and to said cable (3a); Equipped with the control interface (22) of the remote antenna module and the control interface (12) of the central control unit are suitably configured to transmit the input / output data signals (S0, St) at a first intermediate frequency (IF1) and control signals (S1, S2) at a second intermediate frequency (IF2) via the cable (3a) to control the control interface (22) of the remote antenna module and the RF front end (21); the remote antenna module (2) comprises a plurality of radiating elements (20) having a steerable beam and configured to transmit and receive signals at millimeter waves (mmW) above 20 GHz; The RF front end (21) is configured to receive a control signal (S2) from the central control unit (1) and perform beamforming of the plurality of radiating elements (20) of one remote antenna module; The control interface (22) a frequency converter (23) for receiving an input data signal (S0) of millimeter waves and converting it into an input data signal of a first intermediate frequency (IF1) lower than the millimeter waves so that it can be transmitted through the cable (3a), and for receiving an output data signal (St) of a frequency lower than the millimeter waves and converting it into an output data signal of mmW so that it can be transmitted to the radiating element (20); a control device (24) configured to receive the control signals (S1, S2) coming from a control device (14) of a central control unit (1), the control signals (S1, S2) being transmitted via a cable (3 a) at a second intermediate frequency (IF2) different from the first intermediate frequency (IF1) of the input / output data signals (S0, St); Equipped with the cable (3a) is a coaxial cable connecting the remote antenna module (2) to the central control unit (1) and transmitting the input / output data signals (S0, St), the control signals (S1, S2) and the power supply signal (A) simultaneously; An antenna system (100) for in-vehicle mobile radio communications, comprising:

2. the plurality of radiating elements (20) in the remote antenna module are an array of radiating elements; Antenna system (100; 300) according to claim 1, characterized in that

3. The control interface (12) of the central control unit includes a DA / AD conversion unit (16), The DA / AD conversion unit (16) an analog-to-digital converter for converting the input data signal (S0) of the first intermediate frequency (IF1) transmitted from the frequency converter (23) via the coaxial cable (3a) from analog to digital; a digital-to-analog converter for converting from analog to digital the output data signal (S0) delivered from the signal processor (10) at the first intermediate frequency (IF1) for transmission via the coaxial cable (3a) to the frequency converter (23); Equipped with 2. The antenna system (100) of claim 1,

4. The control device (14) of the central control unit comprises an UP frequency converter that converts the control signals (S1, S2) transmitted from the signal processor (10) to the second intermediate frequency (IF2) different from the first intermediate frequency (IF1), The control device (24) of the remote antenna module includes a DOWN frequency converter that converts the control signals (S1, S2) transmitted from the control device (14) of the central control unit into low-frequency control signals (S1, S2) suitable for controlling the frequency converter (23) and the RF front end (21).

4. An antenna system (100) according to claim 3, characterized in that:

5. The central control unit (1) comprises a power supply block (15) connected to a power supply block (25) of the remote antenna module by the coaxial cable (3a), for supplying power to the operating components of the remote antenna module.

2. The antenna system (100) of claim 1,

6. The power supply block (25) of the remote antenna module is connected to the control device (24) of the remote antenna module, so that a diagnostic signal (S4) indicating the status of the power supply block (25) of the remote antenna module is sent; the control device (24) of the remote antenna module comprises an UP frequency converter which converts the diagnostic signal (S4) coming from the power supply block (25) into a diagnostic signal of the second intermediate frequency so that it can be transmitted via the coaxial cable (3a); the control device (14) of the central control unit comprises a down-frequency converter, which converts the diagnostic signal (S4) from the second intermediate frequency (IF2) to a suitable frequency for transmission to the signal processor (10); 6. An antenna system (100) according to claim 5, characterized in that:

7. at least one remote antenna module (2) connected to a central control unit (1) by a cable (3b); The remote antenna module (2) at least one radiating element (20) suitable for transmitting and receiving input / output data signals (S0, St); an RF front end (21) suitable for amplifying, phase controlling and routing said input / output data signals (S0, St); a control interface (22) connected to said RF front end (21) and to said cable (3b); Equipped with The central control unit (1) a signal processor (10), a control interface (12) connected to said signal processor (10) and to said cable (3b); Equipped with the remote antenna module (2) comprises a plurality of radiating elements (20) having a steerable beam and configured to transmit and receive signals at millimeter waves (mmW) above 20 GHz; The RF front end (21) is configured to receive a control signal (S2) from the central control unit (1) and perform beamforming of the plurality of radiating elements (20) of one remote antenna module; The cable (3b) is a digital cable, the remote antenna module (2) comprises a control device (124) suitably configured to encapsulate an input data signal (S0) together with a diagnostic signal (S4) received from the control device (124) to obtain a first encapsulated signal (C1) to be transmitted via a digital cable (3b); the control interface (12) of said central control unit (1) comprises a control device (114) suitable for encapsulating the output data signal (St) with the control signals (S1, S2, S3) to obtain a second encapsulated signal (C2) to be transmitted to said cable (3b); the control device (114) of the central control unit (1) is configured to decapsulate the first encapsulated signal (C1) to obtain the input data signal (S0) and the diagnostic signal (S4); a control device (124) of the remote antenna module (2) configured to decapsulate the second encapsulated signal (C2) to obtain the output data signal (St) and the control signals (S1, S2, S3); An antenna system (300) for in-vehicle mobile radio communication, comprising:

8. The control interface (22) of the remote antenna module (2) comprises a frequency converter (23), The frequency converter (23) receiving said input data signal (S0) of millimeter wave and converting it into an input data signal of a first intermediate frequency (IF1) lower than said millimeter wave so that it can be transmitted via said cable (3b); receiving the output data signal (St) at a frequency lower than the millimeter wave and converting it into an output data signal of mmW for transmission to the radiating element (20); 8. An antenna system (300) according to claim 7, characterized in that:

9. The control interface (22) of the remote antenna module comprises a DA / AD converter (26) connected to the frequency converter (23) and the control device (124); The DA / AD conversion unit (26) an AD converter that converts the input data signal (S0) of the first intermediate frequency (IF1) transmitted from the frequency converter (23) into a digital signal; a digital-to-analog converter for converting the output data signal (S0) transmitted from the control device (124) of the remote antenna module into analog; Equipped with 9. An antenna system (300) according to claim 8, characterized in that

10. The control device (114) of the central control unit (1) comprises an encoding / decoding logic circuit (115), a serializer / deserializer (116), a clock recovery / phase-locked loop (PLL) (117), and a line driver (118); the central control unit (1) comprises a clock generator (119) connected to the PLL (117) so that the PLL can generate a clock signal (Sc) to be sent to the serializer (116); The control unit (124) of the remote antenna module (2) comprises a line driver (128), a deserializer / serializer (126), a clock recovery / PLL unit (127), and a decoding / encoding logic circuit (125). Antenna system (300) according to any one of claims 7 to 9, characterized in that it

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