The present invention relates generally to satellite communication systems. More particularly but not exclusively, the present invention relates to systems and methods for satellite communications using multiple transponders to maximize transponder performance and reduce receiver complexity.
Advances in satellite technology have resulted in the development of transponders having increased transmission power, improved low-noise amplifier (LNA) characteristics, and smaller receiving antennas. As the trend toward higher power transponders continues, existing lower-power transponders have become increasingly available at lower cost.
In existing systems using multiple transponders, it is necessary for the receiver to have multiple antennas and a timing signal to synchronize the signals received from the multiple satellite transponders. Consequently, these receivers are relatively complex and expensive. Therefore, the potential cost savings associated with lower-cost transponders has heretofore been offset by the higher acquisition cost of the receiver unit. Moreover, for portable satellite receivers, it is typically important to have a small receiving antenna and reduced receiver complexity. Using conventional approaches, it is difficult to obtain acceptable signal-to-noise ratios with low power transponders used in conjunction with small receiving antennas. Accordingly, there is a need for alternate approaches to multiple satellite transponder use in conjunction with a simplified receiver design.
The present invention is directed generally to systems and methods for providing digital content in conjunction with a satellite having a plurality of transponders.
In one aspect, embodiments of the present invention relate to a content receiver configured to receive a plurality of transponder signals from a satellite and combine the signals to generate a combined signal, the combined signal based on a composite signal provided to the satellite.
In another aspect, embodiments of the present invention relate to an uplink apparatus configured to receive a digital data signal, divide the digital data signal into a plurality of divided signals, and recombine the divided signals to generate a composite signal that may be provided to a satellite for transmission to a content receiver.
In another aspect, embodiments of the present invention relate to a system comprising an uplink apparatus and a content receiver, the uplink apparatus configured to receive a digital data signal, divide the digital data signal into a plurality of divided signals, and recombine the divided signals to generate a composite signal. The composite signal may then be transmitted to a satellite where it may be separated into a plurality of transponder signals, with the transponder signals then transmitted to a content receiver configured to receive the plurality of transponder signals and recombine the transponder signals to regenerate the original digital data signal.
Additional aspects of the present invention are further described and illustrated with respect to the detailed description and figures.
The invention is more fully appreciated in connection with the following detailed description taken in conjunction with the accompanying drawings, wherein:
b is a schematic and circuit block diagram of a satellite uplink apparatus in accordance with an embodiment of the present invention.
a illustrates a satellite and transponder configuration in accordance with aspects of the present invention.
b illustrates an embodiment of signals associated with the satellite and satellite transponder shown in
In the following description reference is made to the accompanying drawings wherein are shown, by way of illustration, several embodiments of the present invention. It is understood by those of ordinary skill in the art that other embodiments may be utilized and structural changes made without departing from the spirit and scope of the present invention. Like elements are marked throughout the specification and the drawings with the same respective reference designators unless indicated otherwise.
Advances is satellite technology have resulted in the development of transponders having increased transmission power, improved low-noise amplifier (LNA) characteristics, and smaller receiving antennas. As the trend toward higher power transponders continues, existing lower-power transponders have become increasingly less expensive to use. The availability of these low-cost satellite communication system presents an opportunity to provide high-throughput, low cost satellite communication systems by combining multiple satellite transponders to transmit data that was previously transmitted over a single transponder.
In existing systems using multiple transponders, it is necessary for the receiver to have multiple antennas and a timing signal to synchronize the signals received from the multiple satellite transponders. Consequently these receivers are relatively complex and expensive. Therefore, the potential cost savings associated with lower-cost transponders has heretofore been offset by the higher acquisition cost of the receiver unit. Moreover, for portable satellite receivers, it is typically important to have a small receiving antenna and reduced receiver complexity. Using conventional approaches, it is difficult to obtain acceptable signal-to-noise ratios with low power transponders used in conjunction with small receiving antennas. As described in further detail below, embodiments of the present invention address these concerns as well as others by facilitating use of multiple satellite transponders in conjunction with a satellite receiver operating at a low signal-to-noise ratio while using a simplified design with fewer components.
In accordance with aspects of the present invention, embodiments provide an improved satellite receiver that can be used in a satellite data transmission system comprising multiple satellite transponders.
In one aspect, embodiments of the present invention relate to an uplink apparatus configured to receive a digital data signal, divide the digital data signal into a plurality of divided signals, and recombine the divided signals to generate a composite signal that may be provided to a satellite for transmission to a content receiver. In one embodiment, digital data is modulated, power divided, and then summed to generate the composite signal. In another embodiment, digital data is modulated, content divided, and then summed to generate the composite signal.
In accordance with another aspect, embodiments of the present invention relate to transmission of the composite signal to a satellite having a plurality of satellite transponders. The composite signal is processed and retransmitted by the transponders to a content receiver.
In accordance with another aspect, embodiments of the present invention relate to a content receiver configured to receive a plurality of transponder signals from a satellite and combine the signals to generate a combined signal, the combined signal based on a composite signal provided to the satellite. In accordance with some embodiments, the plurality of transponder signals results in a higher power level for the combined signal, thereby enabling smaller antennas at the receiver unit and/or enhanced signal characteristics. In addition, the increased power may result in a larger transmission range, increased signal reliability, or increased data rate. The plurality of transponder signals may be received by a single antenna and provided to the content receiver from the antenna, thereby avoiding use of a timing signal. This may provide advantages including allowing use of a single beam antenna rather than a multi-beam antenna, with only one directional antenna required to receive signals from the plurality of satellite transponders. In addition, if a single directional antenna is used, the filtered transponder signals may be closely time-correlated, resulting in processing circuitry in the receiver that is able to combine the content of multiple received transponder signals without the need for memory buffers, a timing signal and/or a controller system.
In accordance with aspects of embodiments of the present invention, significant flexibility in the transmission of data signals using multiple transponders may be provided. For example, in typical embodiments where multiple transponders are receiving and retransmitting the same content, the added transponders may increase the channel's robustness by increasing its power for a faster data rate, increased reliability, and/or a longer transmission range. Embodiments of the invention may also provide greater flexibility for satellite communications by not limiting the communication between the transmitter and receiving units to a specific transponder, since the assignment of transponders may be done arbitrarily. For example, if one satellite becomes inoperable, transponders on another satellite may be used to transmit data using the techniques described herein.
Additional details related to embodiments of the present invention are further described below with respect to the drawings.
Attention is now directed to
Composite signal generation module 150 is configured generally to receive a digital data signal, divide the digital data signal into a plurality of divided signals, and recombine the divided signals to generate as output a composite data signal. The digital data signal is typically based on input digital data 130a, with digital data 130a being a digital data stream, packet, frame or other form of digital data. The digital data signal may be a digital signal in an analog form, such as a modulated digital signal based on digital data 130a. For example, in one embodiment the digital data signal is provided to composite signal generation module 150 from a data converter 140, where data converter 140 receives input baseband digital data 130a and modulates it to a first intermediate frequency (IF), providing the first IF modulated signal to composite signal generator 150.
The composite signal output of composite signal generation module 150 is then provided to satellite transmitter 107, with the transmitted composite signal 170 sent to satellite 108. In typical embodiments transmission of the composite signal may be done using standard satellite transmission techniques such as are known in the art.
As described in greater detail below, satellite 108 comprises a plurality of transponders that are configured to receive the transmitted composite signal 170, extract composite signal components, and retransmit the extracted components, as a plurality of transponder component signals 180a-n, to satellite reception antenna 112 coupled to content receiver 110. Antenna 112 receives the transponder component signals 180a-n nearly simultaneously, since the individual component signals are typically extracted from the composite signal 170 and retransmitted by the satellite transponders at substantially the same time, and provides the transponder component signals to content receiver 110. Content receiver 110, which may be part of a mobile or portable device 160, then processes and recombines the component signals to regenerate the input data signal.
In typical embodiments, content receiver 110 includes a plurality of receiver modules 120a-120n which include a plurality of tuners 114a-114n that extract a baseband analog signal from the received transponder component signals. The baseband analog signals are digitized by a set of analog-to-digital converters 116a-116n and then summed by a signal combiner 118 to regenerate a recombined version 130b of digital data 130a. Recombined digital data 130b may then be provided as output, such as for further processing and/or storage in a memory 165 of portable device 160. Additional details of embodiments of content receivers are described below with respect to
In addition, after being output from content receiver 110, digital data 130b may be further processed and/or rendered, such as is described in further detail in the related applications, to provide audio, video, text, images or other forms of content output. In one embodiment, the output digital data may be used to provide user personalized content as is described in the related applications.
It is noted that portable device 160 as shown in
Attention is now directed to
Input digital data 130a is provided to converter module 140, which includes digital-to-analog baseband processor 101 and modulator 103. In converter module 140, digital-to-analog baseband processor 101 receives digital data 130a and converts the data to an analog baseband signal, which is then provided to modulator 103. The baseband analog signal may then be modulated to a first intermediate frequency (IF) digital signal by modulator 103, such as, for example, at an IF of 70 MHz. The first IF signal may then be provided to signal divider 104, where it may be divided into a plurality of divided signals based on a signal division criteria such as signal power, signal content, or other signal division criteria. In a typical embodiment the divided signals will be a plurality of signals at a modulated frequency such as the first IF frequency.
In accordance with one embodiment implementing power division, each of the plurality of divided signals provided by signal divider module 104 may contain the same information at the same data or symbol rate, but with a proportionate fraction of the power of the input signal.
In another embodiment implementing content division, the first IF modulated signal is divided into a plurality of divided signals whereby each divided signal is provided at a lower data rate than the input data signal 130a, with each divided signal having some portion of the data of the input data signal. The divided signals will typically have the same power as the input signal. In some embodiments, the divided signals each carry a mutually exclusive portion of the data in the input data 130a, with the power of each of the divided signals being the same as the input signal. In these embodiments content division can be performed based on bit-by-bit data division, division by data packets, division by data frames, or by other data division criteria.
In either of the power or content division embodiments, as well as in others, the divided signals provided by signal divider 104 may be then be recombined in signal combiner 106. In a typical embodiment, the divided signals are provided to a plurality of frequency converters 105a-105n as shown in
The composite signal may then be provided to satellite transmitter 107 which may comprise an upconverter 109, an amplifier 111, a transmitter 113 and an associated transmit antenna 145. The composite signal may be upconverted in upconverter 109, provided to amplifier 111 for any additional desired amplification, and then provided to transmitter 113 and associated antenna 145 for transmission as composite signal 170 to satellite 108.
It is noted that the above provided description of the uplink apparatus does not necessarily have to be performed in the specific order described or with the described components—other signal division, recombination, upconversion and signal transmission methods may alternately be used within the spirit and scope of the present invention. For example, in some embodiments other data division and combining apparatus may be used. In some embodiments digital data 130a may be divided at baseband and then upconverted directly to the plurality of second intermediate frequency signals before recombining. Moreover, the composite signal does not necessarily need to comprise a frequency division multiplexed signal—other signal combination methods may alternately be used in some embodiments. Other components may also be interchanged or reconfigured. For example, in some embodiments the digital-to-analog converter may be configured subsequent to the signal division stage in the processing chain. Further, the upconversion depicted is illustrative of an upconversion to the Ku-band (11.7 GHz to 14.5 GHz) or the C-band (3.7 GHz to 6.425 GHz) based on their common use in satellite communications. However, embodiments of the present invention are not limited to a specific frequency band, and other operating bands and corresponding upconversion methods and apparatus may equally be used.
Attention is now directed to
At the start of the signal processing represented by
Attention is now directed to
The composite signal generated by composite signal generation module 150 may be sent from satellite transmitter 107 as composite signal 170 and received at the receive (RX) interface 304 of satellite 108 via one or more antennas (not shown). The composite signal may then be downconverted by downconverter 306 to a composite satellite IF signal as illustrated in visual representations 320a and 320b of
Although typical embodiments of the present invention will comprise multiple transponders on a single satellite, in some embodiments multiple transponders on two or more satellites may alternately be used. In addition, while typical embodiments will comprise a satellite configured to implement the functionality described above, in some embodiments other communication technologies configured to receive a composite signal and separate and retransmit the composite signal as a plurality of component signals to a component receiver may alternately be used.
Attention is now directed to embodiments of content receivers configured to receive and process the plurality of transponder signals in accordance with aspects of the present invention.
Antenna 112 receives the plurality of signals from a satellite, such as transponder signals 180a-n from satellite transponders 308a-n illustrated in
In one embodiment, receiver modules 420a-n each include a tuner module 403a-n, an analog to digital converter module 404a-n, and a digital demodulator 405a-n. The tuner modules may be configured as shown in
Analog to digital converters 404a-n then receive the I and Q signals and convert the signals to digitized signals. The digitized signals may then be digitally demodulated at digital demodulators 405a-n to filter out any signal by-products from the previous signal processing and to improve the signal-to-noise ratio. In a content division embodiment the signals will typically be provided at a lower data rate than the original digital data signal 130a. For example, if the original data signal 130a is divided into two components at the signal divider 104, each of the receiver module output signals would be provided at half the data rate of the original data signal 130a.
The signals may then be combined at combiner 406 to recreate the original digital data as regenerated digital data 130b. Combiner 406 will typically including interface circuitry to interface to the plurality of receiver modules 420a-n as well as a combiner circuit to combine the plurality of receiver signals so as to generate as an output digital data 130b. In some embodiments the combiner circuit comprises an adder circuit configured to sum the receiver 420a-n outputs to generate digital data 130b. Digital data 130b may then be further processed, stored, and/or rendered, such as on portable device 160. In addition, the output data 130b may be further applied to an error correction module 407 to further improve the signal quality, and the error-corrected version of digital data 130b may then be provided for further processing and/or storage in a memory of portable device 160, such as memory 165.
Antenna 112 receives the plurality of signals from a satellite, such as signals 180a-n from satellite transponders 308a-n illustrated in
In one embodiment, receiver modules 520a-n each include a tuner module 503a-n and an analog to digital converter module 504a-n. The tuner modules may be configured as shown in
Analog to digital converters 504a-n then receive the I and Q signals and convert the signals to digitized signals. The digitized signals may then be combined at combiner 505 to generate a combined receiver output signal, the combined receiver output signal typically having a higher signal to noise ratio. The combiner 505 typically including interface circuitry to interface to the plurality of receiver modules 420a-n as well as a combiner circuit to combine the plurality of receiver output signals so as to generate the combined output signal. In some embodiments the combiner circuit comprises an adder circuit configured to sum the receiver 520a-n outputs to generate the combined receiver output signal, which will typically be an undemodulated signal in power division embodiments.
The combined output signal may then be applied to digital demodulator 506 to recreate the original digital data 130a as regenerated digital data 130b, which may then be further processed, stored, and/or rendered on portable device 160. In addition, digital data 130b may be further applied to an error correction module 508 to further improve the signal quality, with the error-corrected version of digital data 130b then provided as output for further processing and/or storage in a memory of portable device 160, such as memory 165.
The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it is apparent to one of ordinary skill in the art that specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description, not limitation. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously, many modifications and variations are possible in view of the above teachings. Consequently, variations and modifications of the embodiments disclosed herein may be made without departing from the spirit and scope of the invention as set forth by the claims.
The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications; they thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.
This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 60/894,892, entitled SYSTEM AND METHOD FOR UTILIZING MULTIPLE SATELLITE TRANSPONDERS FOR DATA DISTRIBUTION, filed Mar. 14, 2007. This application is related to U.S. Utility patent application Ser. No. 11/955,299, entitled METHOD AND APPARATUS FOR INTERACTIVE DISTRIBUTION OF DIGITAL CONTENT, filed on Dec. 12, 2007, to U.S. Utility patent application Ser. No. 11/923,573, entitled METHODS AND SYSTEMS FOR PERSONALIZED RENDERING OF DIGITAL MEDIA CONTENT, filed on Oct. 24, 2007 and to U.S. Utility patent application Ser. No. 11/923,554, entitled SYSTEMS AND DEVICES FOR PERSONALIZED RENDERING OF DIGITAL MEDIA CONTENT, filed on Oct. 24, 2007. The contents of each of these applications is hereby incorporated by reference herein in its entirety for all purposes.
Number | Date | Country | |
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60894892 | Mar 2007 | US |