Patent Application
20250158702
The present invention is generally in the field of communication systems, and particularly relates to techniques of augmenting terrestrial communication equipment and infrastructures.
This section intends to provide background information concerning the present application, which is not necessarily prior art.
Conventional terrestrial radio transceivers (e.g., land mobile radio-LMR) operate within a defined radio frequency (RF) band, which is typically partitioned into multiple sub-bands defining various transmit/receive frequency ranges/channels for various RF applications (e.g., LMR, GSM, PCS). Geographic areas requiring RF communication coverage are typically divided into multiple cells, and a certain number of such channels is assigned to each geographic cell according to its traffic loads. When such conventional terrestrial radio transceivers are roaming from one geographic cell to another (i.e., mobile terrestrial radio transceivers), they usually change their communication channels in correspondence with the geographical division of the RF band.
The different frequency channel bands allocated to the geographic cells in RF communication systems are typically referred to as frequency plans (also referred to herein as terrestrial frequency plans). Accordingly, the conventional terrestrial radio transceivers are limited to the certain geographical cell in which the transceiver is being operated and to the specific frequency plan associated with the certain geographical cell. For example, LMR communication systems typically utilize communication channels that are 25 KHz wide in the low and high very-high-frequency (VHF) bands (30-50 MHz and 150-172 MHz), and in the ultra-high-frequency (UHF) band (450-512 MHz).
LMR communication systems (such as push-to-talk-PTT voice communication) are designed for extreme reliability in difficult environments, enabling instant communication between teams members, and thus they are a backbone necessity for operation of many civil, public, military, and government agencies. LMR communication can be conducted utilizing handheld, vehicle-mounted, and/or fixed base, radio transceivers, to provide users the ability to instantly communicate and coordinate efforts during routine and emergency operations, which is crucial for public safety protection and live saving operations (e.g., law enforcement, fire rescue, emergency medical services-EMS, and suchlike).
There are however various threats to LMR communication systems due to the ability to easily intercept their transmissions utilizing off-the-shelf commercially available equipment. There are also available devices that can be configured to act as LMR system users, giving them the ability to intercept and send messages. In addition, LMR communication systems are typically susceptible to deliberate and/or accidental interferences e.g., due to amateur/pirate deployment of RF equipment and/or regular electrical noise sources. The wide-spread and availability of web-based applications, frequency jammers, radio cloning devices, and encryption-breaking software can seriously challenge LMR communication systems. Though encryption can be used to implement secure LMR communication infrastructures, it is a complex, resource hungry, expensive to purchase and manage technology, which requires in-depth understanding and careful/persistent management.
The communication of conventional terrestrial RF systems is usually susceptible to the geographic conditions characterizing the geographical cells in which they operate. For example, communication between users is typically tampered when line-of-sight (LOS) between the antennas of the terrestrial RF transceivers, and/or with their relay/base station(s), is lost e.g., due to obstructions, such as terrain barriers/mountains, buildings, and/or rough weather conditions, or can be severely interfered due to RF reflections. There are currently no satisfactory solutions to the coverage, capacity and security, concerns associated with the conventional terrestrial RF communication, and their limiting frequency plans.
Some related solutions known from the patent literature are briefly described hereinbelow.
International Patent Publication No. WO 1999/21276 discloses a mobile radio for use in multiple different frequency plans. The multiple different frequency plans, such as land-based plans (cellular, land mobile radio, etc.) and satellite-based plans may employ different frequency bands and, within those different bands, different frequency channel step sizes. The mobile radio employs only a single loop synthesizer to accommodate all of the different plans, including all of the different channel step sizes. It does so by employing a dynamically programmable divider circuit within the single loop synthesizer for macro-adjustment of the local oscillator frequency and a dynamically adjustable reference oscillator within the single loop synthesizer for micro-adjustment of the local oscillator frequency depending upon a recovered carrier signal.
US Patent Publication No. 2008/218427 discloses a multiple mode communications transceiver which includes an antenna for receiving and transmitting RF energy and a first circuit selectively coupled to the antenna for transmitting and receiving FM modulated signals for terrestrial based communications. The transceiver also includes at least a second circuit selectively coupled to the antenna for transmitting and receiving satellite signals and a control circuit for selecting which of the first and second circuits are employed by the transceiver for the reception and transmission of information.
US Patent Publication No. 2003/060195 discloses a dual-mode telephone with a satellite communication adapter. According to one embodiment a cellular-type hand-portable phone is equipped with a connector for the attachment of accessories. This connector provides a satellite communications adapter accessory access to the handset's signal processing resources which may operate in an alternative mode to process signals received from the satellite and converted by the adapter into a suitable form for processing. The processing translates the satellite signals into voice or data, and vice-versa.
Terrestrial RF communication systems have limited coverage and capacity, and their security can be easily breached, allowing unauthorized users to easily intercept and interfere the RF communications, and/or impersonate authorized participants. The increased availability of relatively inexpensive RF equipment nowadays imposes serious threats to management of critical mission operations and routine public safety operations, which primarily rely on types of instant terrestrial RF communication infrastructures, such as LMR/PTT RF communication.
The present application provides techniques for augmenting terrestrial RF communication equipment and infrastructures, and easily enabling to increase its capacity, coverage and security. In a broad aspect these goals are achieved in embodiments disclosed herein by relaying the conventional terrestrial RF communication over satellite communication channels e.g., utilizing geostationary communication satellites. In this way, the limited geographical coverage of conventional RF communication equipment/infrastructures can be increased up to the full geographical coverage of the satellite and/or its spot beam(s), the capacity of conventional RF communication systems can be greatly increased up to the limits of the satellite communication system used, and the security of the RF communication is also increased as satellite communication is more difficult to intercept and tamper with.
These and other objects of this disclosure are achieved in some embodiments by coupling the conventional terrestrial RF communication devices/equipment to a communication converter configured, in the transmit path, to receive the RF transmission generated by the RF communication devices/equipment and transmit it over a satellite uplink communication carrier to a satellite responder, and in the receive path receive over a downlink satellite carrier the RF transmissions conducted in the system.
The communication converter utilizes a terrestrial-to-satellite (T/S) communication converting unit configured to receive the terrestrial RF communication signals generated by a conventional terrestrial RF transceiver coupled thereto and relay it over a satellite uplink communication carrier to a satellite responder, and a satellite-to-terrestrial (S/T) communication converting unit configured to receive downlink satellite communication and extract therefrom terrestrial RF communication signals thereby relayed. For this purpose, the disclosed communication converter is equipped in some embodiments with a RF signal port configured for coupling of the terrestrial RF communication signals from the conventional terrestrial RF transceiver thereinto for relay over the satellite carrier by the T/S unit, a satellite antenna configured for transmission of the modulated uplink satellite carrier used by the T/S unit and for receiving the downlink satellite transmissions for extracting by the S/T unit the terrestrial RF communication signals thereby carried.
In possible embodiments the terrestrial RF transceiver is a type of push-to-talk (e.g., handheld/LMR) radio device. Embodiments hereof accordingly configured to provide PTT radio super smart satellite frequency converter seamlessly implementing the T/S and S/T functionalities utilizing the satellite antenna, so as to provide transparent functionality allowing keeping all PTT radio (e.g., modulation, coding, encryption, etc.) parameters the same. The disclosed embodiments can be configured to support all line-of-sight (LOS) PTT frequencies in the 50-950 MHz radio range, and/or all analog and digital constant envelope modulations, such as, but not limited to, FM, NXDN, P25, Tetra, DMR, ANDVT, CSVD (12K/16K), and suchlike.
The conventional satellite communication equipment available nowadays is typical configured to occupy the satellite communication channel(s) thereby used upon activation and throughout the entire communication i.e., other satellite communication device cannot use the satellite communication channel(s) for substantial long time periods. In embodiments hereof, the use of the satellite transmission channel/path of the communication converter is configured to optimize exploitation of the satellite communication channel(s) for allowing many users of the communication system to transmit and broadcast only when it is needed. This optimization of the satellite communication channel(s) is achieved by activating the satellite transmission channel/path of the communication converter for satellite transmission only when the terrestrial RF communication signals are received from the conventional terrestrial RF transceiver (i.e., only in the PTT mode), such that the satellite communication channel(s) is kept available and unoccupied for use by all other satellite devices in the system.
Optionally, but in some embodiments preferably, the disclosed communication converter further includes a detection unit configured to identify transmission of terrestrial RF communication signals from the conventional terrestrial RF transceiver and generate data/signals indicative thereof, and/or identify reception of the downlink satellite carrier and generate data/signals indicative thereof. The communication converter can be accordingly configured to change its mode of operations between the T/S and S/T modes, based on the data/signals generated by the detection unit. The communication converter and its detection unit this way can be configured to provide smart detection and rapid switching between transmission and reception modes, as will described hereinbelow in detail.
For example, the communication converter comprises in some embodiments a first switch device configured to controllably convey the terrestrial RF communication signals from the conventional terrestrial RF transceiver to the T/S unit based on data/signals generated by the detection unit indicative of the T/S mode of operation, or to convey the terrestrial RF communication signals extracted by S/T unit to the conventional terrestrial RF transceiver based on data/signals generated by the detection unit indicative of the S/T mode. A second switch device can be similarly used in the communication converter to controllably convey the satellite uplink communication signals generated by the T/S unit for transmission by the satellite antenna based on data/signals generated by the detection unit indicative of the T/S mode of operation, or to convey the satellite downlink communication signals received by the satellite antenna to the S/T unit based on data/signals generated by the detection unit indicative of the S/T mode.
A control unit is used in some embodiments to change the operating mode of the communication converter between the T/S and S/T modes. Namely, the control unit can be configured to set the states of the first and second switches based on the data/signals indications generated by the detection unit, and/or to operate the T/S and S/T units accordingly. One or more signal generators may be used for generating local oscillator signals for the uplink satellite communication signal generated by the T/S unit and for the extraction/demodulation of the terrestrial RF communication signals by the S/T unit. In some embodiments a single signal generator is used to controllably generate the local oscillator signals based on the data/signals generated by the detection unit and/or control signals generated by the control unit i.e., responsive to setting the communication converter into the T/S or S/T operation mode.
Optionally, but in some embodiments preferably, the control unit is further configured to instruct the signal generator to use a first frequency (also referred to herein as conversion frequency) for local oscillator signal thereby generated for the uplink satellite communication signal generated by the T/S unit, and to use a second frequency (also referred to herein as extraction frequency) for the local oscillator signal thereby generated for the extraction/demodulation of the terrestrial RF communication signals by the S/T unit. A memory is used in some embodiments in the communication converter to store one or more pairs of such first and second frequencies for generation of the local oscillator signals. The control unit can be accordingly configured to select a suitable pair of frequencies from the one or more frequency pairs stored in the memory, for use by the signal generator in the T/S and S/T operation modes based on geographical location of the terrestrial RF transceiver to which the communication converter is coupled i.e., based on the frequency plan of the terrestrial RF transceiver and/or satellite spot beam coverage of the satellite used to augment the terrestrial RF communication.
In one aspect the present application is directed to a communication converter comprising a terrestrial-to-satellite (T/S) conversion unit configured to receive and convert terrestrial RF communication signals into uplink satellite communication signals, and to receive downlink satellite communication signals and extract therefrom terrestrial RF communication signals thereby carried. The communication converter comprises in some embodiments one or more signal generators configured to generate local oscillator signals for the conversion of the terrestrial RF communication signals into the uplink satellite communication signals, and for the extraction of the terrestrial RF communication signals from the downlink satellite communication signals. The terrestrial-to-satellite (T/S) conversion unit is configured in some embodiments to modulate a local oscillator signal generated by the one or more signal generators with the terrestrial RF communication signals received by the communication converter. In possible embodiments the communication converter comprises a satellite-to terrestrial (S/T) conversion unit configured to use a local oscillator signal generated by the one or more signal generators to extract the terrestrial RF communication signals from the downlink satellite communication signals received by the communication converter.
A detection unit is used in the communication converter according to possible embodiments to detect the reception of the terrestrial RF communication signals, or of the downlink satellite communication signals, and generate data/signals indicative thereof. The communication converter can be configured to change mode of operation thereof between a T/S and S/T modes based on the data/signals generated by the detection unit. The communication converter can thus comprise a first switch device for coupling the communication converter to a terrestrial RF transceiver. The first switch device can be configured to controllably convey to the T/S conversion unit terrestrial RF communication signals received from the terrestrial RF transceiver, or to convey to the terrestrial RF transceiver terrestrial RF communication signals extracted by the S/T conversion unit.
The communication converter can be configured to use a second switch device for coupling the communication converter to a satellite antenna. The second switch device can be configured to controllably convey to the S/T conversion unit downlink satellite communication signals received from the satellite antenna, or to convey to the terrestrial satellite antenna uplink satellite communication signals generated by the T/S conversion unit.
The communication converter comprises in some embodiments a control unit configured to set the communication converter into the T/S or S/T modes of operation based on the data/signals generated by the detection unit. The control unit can be configured to generate control data/signals for changing the states of the first and second switch devices in accordance with the mode of operation indicated by the data/signals generated by the detection unit.
The control unit can be further configured to instruct the one or more signal generators to use a predefine extraction/demodulation frequency for generation of a local oscillator signal usable to extract the terrestrial RF communication signals from the downlink satellite communication signals, and to use a predefined conversion frequency for generation of a local oscillator signal usable for modulation of the terrestrial RF communication signals received by the communication converter from the terrestrial RF transceiver for generating the satellite uplink communication signals. In possible embodiments the communication converter comprises one or more memories for at least storing the predefined conversion and extraction frequencies. The communication converter may have a plurality of frequency pairs of predefined conversion and extraction frequencies. The control unit can be configured to select one of the plurality of frequency pairs for the generation of the local oscillation signal by the one or more signal generators based at least in part on a geographical location of the terrestrial RF transceiver to which the communication converter is coupled.
The communication converter comprises in some embodiments a power terminal connectable to a power source of said communication converter.
In another aspect the present application is directed to a communication device comprising a (e.g., PTT LMR) terrestrial RF transceiver, a communication converter according to any one of the embodiments disclosed hereinabove or hereinbelow configured to receive terrestrial RF communication signals generated by the terrestrial RF transceiver, and a satellite antenna configured to transmit satellite communication signals generated by the communication converter. The communication converter is coupled in some embodiments to the terrestrial RF transceiver via a waveguiding element (e.g., a coax cable) configured to connect to an antenna port of the terrestrial RF transceiver. Optionally, the communication converter is embedded inside the terrestrial RF transceiver.
The communication device comprises in some embodiments an extension pole configured to connect between the satellite antenna and the communication converter so as to elevate the satellite antenna a predefined distance from the communication converter, for improved downlink and uplink satellite communication. Optionally, but in some embodiments preferably, the satellite antenna is implemented by a type of small omni-directional passive antenna with modified ground plane, configured to optimize the gain to the satellite communication. It is noted that with this configuration of the satellite antenna there is no need to aim the satellite antenna in any particular direction for the conducting the satellite communication, as typically required due to the special ground plane engineering. The link margin achievable with such satellite antenna configuration is in the range of 12 to 16 dBs, depending on specifications of the satellite Tx/Rx communication and the radio waveform thereby used.
The satellite antenna can be a planar passive antenna. In some embodiments the satellite antenna is a type of printed circuit antenna. For example, the satellite antenna can be a type of right-hand circular polarity (RHCP) antenna, or a type of left-hand circular polarity (LHCP) antenna, depending on the GEO satellites used (RHCP for Inmarsat & LHCP for Thuraya).
In yet another aspect the present application is directed to a communication system comprising at least one satellite transponder, and at least two terrestrial RF transceivers having same terrestrial frequency plan and at least two communication converters according to any one of the embodiments disclosed hereinabove or hereinbelow operatively coupled to the at least two terrestrial RF transceivers respectively, and configured to communicate via the at least one satellite transponder, and/or at least two communication devices according to any one of the embodiments disclosed hereinabove or hereinbelow having the same terrestrial frequency plan and configured to communicate via the at least one satellite transponder, for relaying terrestrial RF communication therebetween over the at least one satellite transponder.
Optionally, but in some embodiments preferably, the at least one transponder is mounted on at least one geostationary satellite. Such embodiments thus enable implementation of bent-pipe satellite communication principle e.g., no need for registration, no air-time billing, no identification of end users (i.e., just using satellite bandwidth leased from the satellite provider).
The at least two terrestrial RF transceivers and/or the at least two communication devices can be located within a geographical region associated with a spot beam of the at least one satellite transponder. Optionally, but in some embodiments preferably, the geographical region contains a geographical cell associated with the same frequency plan of the at least two terrestrial RF transceivers and/or of the at least two communication devices. At least one of the at least two terrestrial RF transceivers, and/or of the at least two communication devices, can be located in another geographical region associated with either another spot beam of the at least one satellite transponder or with a spot beam of another satellite transponder that is in satellite communication with the at least one satellite transponder. In possible embodiments the another geographical region is remote from, or nearby to, or at least partially overlap with, a geographical cell associated with the same frequency plan of the at least two terrestrial RF transceivers and/or of the at least two communication devices.
According to yet another aspect the present application is directed to a method of augmenting terrestrial communication. The method comprising receiving a terrestrial RF communication signal from a terrestrial RF transceiver operating with a certain frequency plan, modulating an uplink satellite communication signal with the terrestrial RF communication signal, transmitting the modulated uplink satellite communication signal to a satellite transponder, extracting the terrestrial RF communication signal by the satellite transponder, modulating a downlink satellite communication signal with the extracted terrestrial RF communication signal, and transmitting the modulated downlink satellite communication signal by the satellite transponder to one or more other terrestrial RF transceivers operating with said certain frequency plan.
The method comprises in possible embodiments extracting from the modulated downlink satellite communication signal the terrestrial RF communication signal. The method comprising in some embodiments conveying the extracted terrestrial RF communication signal to the one or more other terrestrial RF transceivers.
The method may comprise using one communication converter to receive the terrestrial RF communication signal from one terrestrial RF transceiver, modulate the uplink satellite communication signal by the terrestrial RF communication signal and transmit it to the satellite transponder, and using one or more other communication converters to receive the modulated downlink satellite communication signal, extract therefrom the terrestrial RF communication signal, and convey the extracted terrestrial RF communication signal to the one or more other terrestrial RF transceivers.
The method comprises in some embodiments configuring the one communication converter and/or the one or more other communication converters to use a certain terrestrial communication plan, and/or a certain uplink satellite communication frequency associated with a satellite transponder, and/or a certain downlink satellite communication frequency associated with a satellite transponder. The configuring is based in some embodiments on a geographical position of the one terrestrial RF transceiver and/or of the one or more other terrestrial RF transceiver.
The method comprises in some embodiments sampling an antenna port of a terrestrial transceiver and continuously extracting from the modulated downlink satellite communication signal the terrestrial RF communication and conveying the same to the terrestrial transceiver, until the sampling is indicative of transmission of terrestrial communication signals by the terrestrial transceiver. Optionally, but in some embodiments preferably, the modulating of the uplink satellite communication signal and the transmitting of the modulated uplink satellite communication signal is carried out when the sampling is indicative of transmission of terrestrial communication signals by the terrestrial transceiver.
In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings. Features shown in the drawings are meant to be illustrative of only some embodiments of the invention, unless otherwise implicitly indicated. In the drawings like reference numerals are used to indicate corresponding parts, and in which:
One or more specific and/or alternative embodiments of the present disclosure will be described below with reference to the drawings, which are to be considered in all aspects as illustrative only and not restrictive in any manner. It shall be apparent to one skilled in the art that these embodiments may be practiced without such specific details. In an effort to provide a concise description of these embodiments, not all features or details of an actual implementation are described at length in the specification. Elements illustrated in the drawings are not necessarily to scale, or in correct proportional relationships, which are not critical. Emphasis instead being placed upon clearly illustrating the principles of the invention such that persons skilled in the art will be able to make and use the augmented terrestrial communication hereof, once they understand the principles of the subject matter disclosed herein. This invention may be provided in other specific forms and embodiments without departing from the essential characteristics described herein.
The present disclosure provides techniques, system and apparatus, for augmenting conventional terrestrial RF communication systems/infrastructures. A principal feature of embodiments disclosed herein is to convey terrestrial RF communication signals generated by a conventional terrestrial RF transceiver over up/down-links of satellite communication infrastructures. Particularly, in possible embodiments, each conventional terrestrial RF transceiver is adapted to transmit its' terrestrial RF communication signals to other conventional terrestrial RF transceivers operated in the same frequency plan over a satellite uplink communication channel, and to receive terrestrial RF communication signals generated by the other conventional terrestrial RF transceivers over a satellite downlink communication channel.
For this purpose, a specially designed communication converter is coupled in some embodiments to each conventional terrestrial RF transceiver. The communication converter is configured in some embodiments to convert the terrestrial RF communication signals generated by the conventional terrestrial RF transceiver to which it is coupled into satellite uplink communication signals, and to extract from satellite downlink communication signals thereby received terrestrial RF communication signals generated by other conventional terrestrial RF transceivers. A satellite antenna can be thus coupled to the communication converter for transmission of the satellite uplink communication signals, and for the reception of the downlink satellite communication signals.
In optional embodiments the communication converter can be embedded into one or more of the conventional terrestrial RF transceivers, so as to provide modified terrestrial RF transceivers capable of relaying their terrestrial RF communication over uplink satellite communication channel(s). Such modified terrestrial RF transceivers can be equipped in some embodiments with a terrestrial RF communication antenna and/or a satellite communication antenna. A switching circuitry may be also incorporated for selecting which of the antennas is to be used by the modified terrestrial RF transceiver for its communication.
For example, but without being limiting, the switching circuitry can be configured as a manual selector switch allowing the user to change the mode of operation of the modified terrestrial RF transceiver between a regular terrestrial RF communication mode (i.e., the RF terrestrial communication is received and transmitted via the terrestrial RF communication antenna only), or a satellite communication mode in which the RF terrestrial communication is relayed over satellite communication channel(s) (i.e., the RF terrestrial communication is conducted using the satellite communication antenna only).
Optionally, the switching circuitry used in the modified terrestrial RF transceiver is further adapted to provide hybrid communication modes. For example, but without being limiting, the switching circuitry may be configured to allow user's selection of a mode in which the RF terrestrial communication is carried out in both regular terrestrial RF communication and also (e.g., simultaneously) relayed over the satellite communication channel(s) (i.e., both the RF terrestrial and the satellite communication antennas are used), and/or to allow user's selection of a mode in which the transmission of the RF terrestrial signals is carried out regularly (i.e., via the RF terrestrial communication antenna) and the reception of the RF terrestrial signals is carried over the satellite communication channel(s) (i.e., via the satellite communication antenna), and/or to allow user's selection of a mode in which the reception of the RF terrestrial signals is carried out regularly (i.e., via the RF terrestrial communication antenna) and the transmission of the RF terrestrial signals is carried over the satellite communication channel(s) (i.e., via the satellite communication antenna).
Alternatively, or additionally, the switching circuitry is configured to receive control signals/data from the control unit for controllably switching the modified terrestrial RF transceiver between the regular terrestrial RF communication mode, the satellite communication mode, or any of the hybrid communication modes e.g., based on preset settings and/or information indicative of RF communication problems, such as, location/position or other information indicative of interfering geographical and/or weather conditions.
For an overview of several example features, process stages, and principles of the invention, the augmented terrestrial communication examples illustrated schematically and diagrammatically in the figures are primarily intended for LMR communication. These LMR communication systems are shown as one example implementation that demonstrates a number of features, processes, and principles used to provide augmented terrestrial communication, but they are also useful for other applications and can be made in different variations. Therefore, this description will proceed with reference to the shown examples, but with the understanding that the invention recited in the claims below can also be implemented in myriad other ways, once the principles are understood from the descriptions, explanations, and drawings herein. All such variations, as well as any other modifications apparent to one of ordinary skill in the art and useful in terrestrial communication applications may be suitably employed, and are intended to fall within the scope of this disclosure.
While the communication between the users U2 and U3 can be carried out directly between their conventional terrestrial transceivers 13, as long the LOS between their terrestrial antennas (not shown) is maintained, the communication between the transceivers 13 of the users U1 and U2 is conducted via the terrestrial relay/base station 19, due to lack of LOS between their terrestrial antennas. Proper continuous operation of terrestrial relay/base station 19 is thus critical in many situations, and any malfunction thereof may jeopardise critical operations and prevent/postpone timely intervention of lifesaving and/or law enforcement professionals in emergency situations. The communication between the transceivers 13 of the users U1, U2 and U3, is of course susceptible to the geographic/terrain/weather limitations and obstructions, and RF reflections interferences, from which conventional terrestrial communication systems typically suffer.
In order to secure the communication and overcome these obstructions/limitations, a communication converter 10 is coupled in some embodiments to the conventional terrestrial transceivers 13 for augmenting their communication capabilities via satellite communication infrastructures. The communication converter 10 is accordingly configured to receive terrestrial RF communication signals generated by the conventional terrestrial transceiver 13 to which it is coupled, configured according to its frequency plan (i.e., based the geographical cell CA in which the users U1, U2 and U3, reside) convert the terrestrial communication signals into satellite communication signals, and transmit the same to the transponder TA of the satellite SA for relaying the same to all other users that utilize the same frequency plan and a communication converter 10 for augmenting their terrestrial RF communication.
Accordingly, in some embodiments, the communication converter 10 is configured to receive satellite communication signals generated by the transponder(s) TA of one or more satellite(s) SA, convert the same into terrestrial communication signals of the respective terrestrial transceivers 13, and supply the same to the antenna port (e.g., 13a in
Thus, in the example shown in
This way, most of the interferences common to terrestrial communication systems, such as due to reflections, obstructions and/or weather conditions, are substantially reduced or eliminated. In addition, it is usually easier for mobile users to maintain LOS with the satellite SA, as compared to maintaining LOS between terrestrial antennas, and thus many of the LOS related communication interferences/problems are also substantially reduced or eliminated. The user U3, however, will be able to communicate with user U1 only via the terrestrial relay/base station 19, as long their antennas are in LOS without interfering/weather obstacles and within acceptable ranges from each other.
In this specific example the user U1 is shown as residing in a geographical area covered by spot beam A1, while the users U2 and U3 are shown as residing in a geographical area covered by satellite spot beam A2, of the satellite SA. It is however noted that the users U1 and U2 utilizing the communication converter 10 according to possible embodiments hereof can similarly reside within a geographical area covered by the same spot beam of satellite SA (e.g., spot beam A1 or A2) to relay their terrestrial communication signals over the transponder TA.
Also exemplified in
For example, the switching circuitry 14 can be configured as a manual or digital (e.g., selected via keypad and/or touchscreen buttons) selector switch allowing the user to change the mode of operation of the modified terrestrial RF transceiver 10/13 between a regular terrestrial RF communication mode (i.e., the RF terrestrial communication is regularly carried out via the terrestrial RF communication antenna only), or a satellite communication mode in which the RF terrestrial communication is relayed over satellite communication channel(s) (i.e., the RF terrestrial communication is conducted over the satellite communication antenna only).
Optionally, the switching circuitry 14 can be further adapted to provide hybrid communication modes e.g., to allow a mode in which the RF terrestrial communication is carried out in both regular terrestrial RF communication and also (e.g., simultaneously) relayed over the satellite communication channel(s) (i.e., both the RF terrestrial and the satellite communication antennas are used), and/or a mode in which the transmission of the RF terrestrial signals is carried out regularly (i.e., via the RF terrestrial communication antenna) and the reception of the RF terrestrial signals is carried over the satellite communication channel(s) (i.e., via the satellite communication antenna), and/or a mode in which the reception of the RF terrestrial signals is carried out regularly (i.e., via the RF terrestrial communication antenna) and the transmission of the RF terrestrial signals is carried over the satellite communication channel(s) (i.e., via the satellite communication antenna).
Alternatively, or additionally, the switching circuitry 14 is a controllable circuitry configured to change the mode of operation of the modified terrestrial RF transceiver 10/13 between the regular terrestrial RF communication mode, the satellite communication mode, and/or any of the hybrid communication modes, based on control signals/data received from a control unit (18 in
The communication converter 10 is configured to support most of the terrestrial RF transceivers 13 commercially available in the markets nowadays. In some embodiments the communication converter 10 is configured to support terrestrial frequency plans in the 50 to 950 MHz frequency range.
Optionally, but in some embodiments preferably, the satellite antenna 11 is a type planar (e.g., printed circuit board-PCB) passive antenna. Optionally, the satellite antenna 11 is a type of right-hand circular polarity (RHCP) antenna e.g., for communicating via INMARSAT satellites The satellite antenna 11 can be accordingly mounted such that its planar surface area is substantially parallel to the ground surface (i.e., facing the sky). As seen, in possible embodiments, the satellite antenna 11 is centered about the extension pole 11p.
As seen in
Referring now to
One or more signal generators (synthesizer) 23 can be used for operating the terrestrial-to-satellite communication converter T/S and the satellite-to-terrestrial communication converter S/T, as will explained in detail hereinbelow. In possible embodiments a single signal generator 23 is used for selectively and controllably generating a transmit (Tx) local oscillator signal having a desired satellite signal modulation frequency FS (e.g., in accordance with an uplink spot beam satellite communication frequency of a satellite used for augmenting the terrestrial communication) for the terrestrial-to-satellite communication converter T/S, or a receipt (Rx) local oscillator signal having a desired terrestrial signal demodulation frequency FT (e.g., in accordance with a downlink spot beam satellite communication frequency of a satellite used for augmenting the terrestrial communication) for the satellite-to-terrestrial communication converter S/T.
The communication converter 10 comprises in some embodiments a control unit 18 (e.g., utilizing one or more processors) and memories 15, configured and operable for storing programs code and/or operational data, used for operation of different functions thereof. For example, the memory can be used for storing the satellite signal modulation frequency FS and/or the terrestrial signal demodulation frequency FT, and the control unit 18 can be configured to determine if the communication converter 10 is required for operation in S/T or T/S mode, and accordingly instruct the signal generator 23 for the generation of the local oscillator signal of the satellite signal modulation frequency FS, or the terrestrial signal demodulation frequency FT stored in the memory 15, and also set accordingly the states of the switches 13w and 11w.
For this purpose, the communication converter 10 comprises in some embodiments a detection module 18d configured to monitor the RF signal port 12r and/or the antenna port 12c, and set the communication converter 10 into the S/T or T/S mode of operation accordingly. Particularly, the detection module 18d can be configured to issue indications for setting the communication converter 10 into its T/S mode upon detection of the terrestrial communication signals 13s at the RF signal port 12r, or into its S/T mode upon detection of the satellite communication signals 11s at the antenna port 12c. The control unit 18 can be accordingly configured to: (i) upon receiving an T/S mode indication from the detection module 18d select the terrestrial signal modulation frequency FS for use by the signal generator 19, and set the switches 13w and 11w to deliver communication signals between the RF signal port 12r and the antenna port 12c via the T/S unit; or (ii) upon receiving an S/T mode indication from the detection module 18d select the satellite signal demodulation frequency FT for use by the signal generator 19, and set the switches 13w and 11w to deliver communication signals between the antenna port 12c and the RF signal port 12r via the S/T unit. The detection module 18d can be implemented by software code executed by the control unit 18, as a separate hardware unit, or as a combination of software code executed by the control unit 18 and separate hardware components.
Optionally, but in some embodiments preferably, the detection module 18d utilizes a power detection (PD) circuitry configured to sample the power of the signal at the RF signal port 12r and based thereon determine if the communication converter 10 should be set into the T/S or S/T mode e.g., the sampled signal power can be rectified (e.g., utilizing one or more diodes—not shown) and/or compared to a predefined threshold value (e.g., utilizing a comparator—not shown) to determine if the sampled signal power is indicative of receipt of the terrestrial RF communication signals from the terrestrial transceiver 13.
Referring now to
The state of the communication converter (10) is changed back into the S/T mode when the sampled signals are not indicative (q3) of terrestrial transmission power and/or frequency at the RF signal port 12r, or after completing the transmission (q4) of the terrestrial RF signals over the satellite uplink channel.
In some embodiments the communication converter 10 comprises a programing module 16 configured for setting desired values for the satellite signal modulation communication frequency FS and/or the terrestrial signal demodulation frequency FT in the memory 15. The communication converter 10 is configured in some embodiment to limit the permission to use the programing module 16 for the setting of the satellite/terrestrial signal modulation/demodulation frequency FS/FT to only authorized operators/technicians. This way, the communication converter 10 can be preset once by an authorized officer for use in compliance with the frequency plan of a specific geographic area intended for use of the respective conventional terrestrial transceiver 13, and for communication with specific one or more satellites which spot beams cover at least some portion of that specific geographic area.
In other possible embodiments the memory 15 may be configured to store a plurality of satellite/terrestrial signal modulation/demodulation FS/FT frequency pairs, where each satellite/terrestrial signal modulation/demodulation FS/FT frequency pair is associated with a certain geographic area. The control unit 18 can be accordingly configured to select and use a suitable satellite/terrestrial signal modulation/demodulation FS/FT frequency pair from the plurality of satellite/terrestrial signal modulation/demodulation FS/FT frequency pairs stored in the memory 15 for use by the communication converter 10. Optionally, a positioning module (e.g., of a global-positioning-system-GPS) is provided in the communication converter 10, or external thereto e.g., in the terrestrial transceiver 13, and the control unit 18 can be accordingly configured to select the suitable satellite/terrestrial signal modulation/demodulation communication FS/FT frequency pair based on positioning data generated by the positioning module 10g.
In a similar fashion, the detection module 18 can be configured to detect the satellite communication signals 11s at the antenna port 12c, and to correspondingly issue a corresponding indication 18i used by the control unit 18 to switch into the S/T mode. Correspondingly, the control unit 18 generate instructions 18f for the signal generator 19 to generate the local oscillator signal in the satellite signal demodulation FT frequency, which is thereby supplied to the S/T unit (Rx RF Chain). The control unit 18 also generates control signals 18s to set the state of the switch 11w for delivery of the satellite communication signals 11s from the the antenna port 12c to the S/T unit, and control signals 18t to set the state of the switch 13w for delivery of the terrestrial communication signals 13s generated by the S/T unit to the RF signal port 12r. In this state the communication converter 10 converts the satellite communication signals 11s received via its antenna port 12c into terrestrial communication signals 13s for transmission to the conventional terrestrial transceiver 13 via its RF signal port 12r.
Corresponding to a T/S mode indication 12i from the detection module 18d, the control unit 18 sets the signal generator 19 to generate the terrestrial signal modulation frequency FS, sets the switch 13w to convey the portion of the terrestrial communication signal 13s from the second terminal of the coupler 13u to the T/S unit, and sets the switch 11w to convey the satellite communication signals generated by the T/S unit to antenna port 12c of the satellite antenna 11. Accordingly, in the T/S mode, the portion of the terrestrial communication signal 13s obtained on the second terminal of the coupler 13u is conveyed by the switch 13w to a terrestrial signal mixer 44t for modulating the local oscillator signal 19t generated by the signal generator 19. As exemplified in
The modulated signal generated by the terrestrial signal mixer 44t can be then processed by one or more filters and/or amplification stages, for transmission via the satellite antenna 11. For example, in possible embodiments the modulated signal from the terrestrial signal mixer 44t is passed through a first band-pass-filter BPF of the T/S unit configured to remove low and/or high frequency components introduced by the terrestrial signal mixer 44t (e.g., to remove the lower-side-band—LSB and/or the upper-side-band—USB). Optionally, but in some embodiments preferably, the signal conveyed to the first BPF of the T/S unit, is passed through an adjustable attenuator unit ATT. The filtered signal from the first BPF of the T/S unit can be than amplified e.g., by RF gain-voltage—GV amplifier. The amplified signal from the GV amplifier can be filtered by a second BPF of the T/S unit configured to remove low and/or high frequency components introduced by the GV amplifier. Finally, the processed modulated signal can be amplified for transmission by a power amplifier (e.g., QP amplifier).
Corresponding to a S/T mode indication 12i from the detection module 18d, the control unit 18 sets the signal generator 19 to generate the satellite signal demodulation frequency FT, sets the switch 11w to convey the satellite communication signal 11s from the antenna port 12c to the S/T unit, and sets the switch 13w to convey the terrestrial communication signals generated by the S/T unit to the second terminal of the coupler 13u. Accordingly, in the S/T mode, the satellite communication signal 11s is conveyed by the switch 11w to a satellite signal mixer 44s for demodulation by the local oscillator signal 19s generated by the signal generator 19. The satellite signal 11s from the switch 11w can be processed by one or more filters and/or amplification stages, before the demodulation by the satellite signal mixer 44s.
For example, as exemplified in
In possible embodiments the demodulated signal from the satellite signal mixer 44s is passed through a low-pass-filter LPF of the S/T unit configured to remove low frequency components introduced by the satellite signal mixer 44s (e.g., to remove the USB), before it is fed into the switch 13w. Optionally, but in some embodiments preferably, the signal conveyed to the switch 13w from the LPF of the S/T unit is passed through an adjustable attenuator unit ATT. The filtered demodulated signal from the switch 13w is fed into the second terminal of the coupler 13u, which outputs a portion thereof to the detection module 18d (e.g., via the ATT), and outputs a portion thereof to the terrestrial transceiver 13 via the RF signal port 12r.
It is noted that the various adjustable attenuators ATTs are optionally used in the communication converter 10 for coordinating the power levels conveyed to the different (e.g., amplification) stages in the T/S and the S/T chains. This way, the communication converter 10 can be controllably switched/adapted for use with different types of conventional terrestrial RF transceivers (e.g., such manufactured by Motorola, Leonardo, Tetron, or suchlike), which typically have different working power levels. However, if the communication converter 10 is used with a specific predefined terrestrial RF transceiver having a known fixed operational power scheme, some or all of the adjustable attenuator units ATT can be removed from communication converter 10, and/or replaced by fixed suitable attenuator units (not shown).
If it is determined that the sampled signals are indicative (s3) of receipt (Rx) of signals having satellite communication frequency and/or power at the satellite antenna port (12c), then the communication converter 10 is switched (s31) into the S/T mode. In the S/T mode (s31), the communication converter 10 extracts (s32) the terrestrial RF signals from the satellite downlink communication signals thereby received via its satellite antenna port (12c) and conveys (s33) the extracted terrestrial RF signals to the terrestrial transceiver (13) via the RF signal port (12r). The sampling (s1) and the mode determining (s2 and s3) stages of the process 50 can be repeated after conveying (s33) the extracted terrestrial RF signals to the terrestrial transceiver (13), or if the sampled signals are not indicative (s3) of receipt (Rx) of signals having satellite communication frequency and/or power at the satellite antenna port (12c).
As also seen in
Relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top” and “bottom”, as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.), and similar adjectives in relation to orientation of the described elements/components refer to the manner in which the illustrations are positioned on the paper, not as any limitation to the orientations in which these elements/components can be used in actual applications.
It should also be understood that throughout this disclosure, where a process or method is shown or described, the steps/acts of the method may be performed in any order and/or simultaneously, and/or with other steps/acts not-illustrated/described herein, unless it is clear from the context that one step depends on another being performed first. In possible embodiments not all of the illustrated/described steps/acts are required to carry out the method.
Those of skill in the art would appreciate that items such as the various illustrative blocks, modules, elements, components, methods, operations, steps, and algorithms described herein may be implemented as hardware (e.g., application specific integrated circuits-ASICs, field-programmable gated arrays-FPGAs) or a combination of hardware and computer software. To illustrate the interchangeability of hardware and software, items such as the various illustrative blocks, modules, elements, components, methods, operations, steps, and algorithms have been described generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application.
As described hereinabove and shown in the associated figures, the present invention provides communication transforming tools usable for augmenting terrestrial RF communication systems/infrastructures, and related methods. While particular embodiments of the invention have been described, it will be understood, however, that the invention is not limited thereto, since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. As will be appreciated by the skilled person, the invention can be carried out in a great variety of ways, employing more than one technique from those described above, all without exceeding the scope of the claims.
