Sirius XM Radio, Inc. Patent applications |
Patent application number | Title | Published |
20140297292 | SYSTEM AND METHOD FOR INCREASING TRANSMISSION BANDWIDTH EFFICIENCY ("EBT2") - Systems and methods for increasing transmission bandwidth efficiency by the analysis and synthesis of the ultimate components of transmitted content are presented. To implement such a system, a dictionary or database of elemental codewords can be generated from a set of audio clips. Using such a database, a given arbitrary song or other audio file can be expressed as a series of such codewords, where each given codeword in the series is a compressed audio packet that can be used as is, or, for example, can be tagged to be modified to better match the corresponding portion of the original audio file. Each codeword in the database has an index number or unique identifier. For a relatively small number of bits used in a unique ID, e.g. 27-30, several hundreds of millions of codewords can be uniquely identified. By providing the database of codewords to receivers of a broadcast or content delivery system in advance, instead of broadcasting or streaming the actual compressed audio signal, all that need be transmitted is the series of identifiers along with any modification instructions to the identified codewords. After reception, intelligence on the receiver having access to a locally stored copy of the dictionary can reconstruct the original audio clip by accessing the codewords via the received IDs, modify them as instructed by the modification instructions, further modify the codewords either individually or in groups using the audio profile of the original audio file (also sent by the encoder) and play back a generated sequence of phase corrected codewords and modified codewords as instructed. In exemplary embodiments of the present invention, such modification can extend into neighboring codewords, and can utilize either or both (i) cross correlation based time alignment and (ii) phase continuity between harmonics, to achieve higher fidelity to the original audio clip. | 10-02-2014 |
20140295885 | SYSTEM AND METHOD FOR IMPROVING TELEMATICS LOCATION INFORMATION AND RELIABILITY OF E911 CALLS - System, devices and methods are provided to automatically initiate an enhanced 911 (E911) call from a telematics control unit (TCU) (e.g., a TCU deployed with cellular modem or mobile phone in a vehicle) to an answering point (e.g. public safety answering point or access point (PSAP)). A wireless carrier (e.g., mobile service center (MSC)) employs a positioning determining entity (PDE) and algorithm to improve caller location determination using information provided by the TCU (e.g., GPS and dead reckoning information generated at the vehicle) and network location information when needed, and provides PDE estimated location of the caller to the PSAP (e.g., using a data channel and optionally a voice channel) to mitigate errors in TCU location data and reduce potentially conflicting location information provided to PSAPs from TCUs and wireless carriers or other phone service providers. | 10-02-2014 |
20140278034 | SYSTEM AND METHOD FOR IMPROVED TRAFFIC FLOW REPORTING USING SATELLITE DIGITAL AUDIO RADIO SERVICE (SDARS) AND VEHICLE COMMUNICATIONS, NAVIGATION AND TRACKING SYSTEM - Systems and methods are provided for improved traffic flow reporting (e.g., system bandwidth conservation and timely traffic flow updates) using in-vehicle devices, service hub, and communications system for transmitting aggregated traffic flow data to the vehicles. In-vehicle devices store data relating to monitored segments of roadways (e.g., segment identifiers or location codes and designated range(s) of speed), and send messages to the hub when current vehicle speed is not within a selected range designated for the current segment of roadway where the vehicle is located. The hub provides updated traffic flow data based on the messages to the communications system for transmission to the vehicles. Vehicles can be configured to send messages based on various criteria. One or more selected vehicles can be commanded to send a message to the hub. Vehicles can respond to location-specified content in broadcast data when they determined themselves to be in the specified location. | 09-18-2014 |
20140223303 | CONTENT CACHING SERVICES IN SATELLITE AND SATELLITE/IP CONTENT DELIVERY SYSTEMS CONTENT CACHING - Systems and methods are presented to facilitate caching of programming from broadcast and/or content streaming services to a user device for local playback. In addition, metadata can be provided to guide the user in selecting, caching, or playing the cachable content. In some exemplary embodiments, a receiver or other user device can automatically select the programming to be cached based on a user's historical topic interest and listening history. In some exemplary embodiments, the metadata can also include DRM information that can limit the ability of a user to playback the content, so as to comply, if necessary, with operative legal requirements related to usage of the content. | 08-07-2014 |
20140194070 | Proprietary Radio Control Head With Authentication - A combination of a radio receiver with a detachable controller that determine sends either reduced or enhanced metadata about received programming to the detachable controller based upon periodic authorization. A connection from the detachable control device to the radio receiver carries commands to the radio receiver and carries only the reduced set of metadata, such as tuned channel and tuned channel name, from the radio receiver to the controller. The controller is authorized by sending a radio identifier from the radio receiver to the control device, determination of an authentication code at the controller and communication of the determined authentication code back to the controller for validation. Upon validation, an enhanced set of metadata, including song title and artist, is sent to the controller. The enhanced metadata, the reduced metadata, or both, are optionally able to be encrypted. The radio receiver periodically performs this authorization processing. | 07-10-2014 |
20140189463 | METHOD AND APPARATUS FOR INTERLEAVING LOW DENSITY PARITY CHECK (LDPC) CODES OVER MOBILE SATELLITE CHANNELS - Systems, methods and apparatus are described to interleave LDPC coded data for reception over a mobile communications channel, such as, for example, a satellite channel. In exemplary embodiments of the present invention, a method for channel interleaving includes segmenting a large LDPC code block into smaller codewords, randomly shuffling the code segments of each codeword and then convolutionally interleaving the randomly shuffled code words. In exemplary embodiments of the present invention, such random shuffling can guarantee that no two consecutive input code segments will be closer than a defined minimum number of code segments at the output of the shuffler. In exemplary embodiments of the present invention, by keeping data in, for example, manageable sub-sections, accurate SNR estimations, which are needed for the best possible LDPC decoding performance, can be facilitated based on, for example, iterative bit decisions. | 07-03-2014 |
20140134940 | WIRELESS SATELLITE DIGITAL AUDIO RADIO SERVICE (SDARS) HEAD UNIT WITH PORTABLE SUBSCRIPTION AND CELL PHONE ABILITIES - A system and method for automated activation of a radio, or content receiver, used to receive subscription radio services such as XM or Sirius radio. A wireless communications device with a short range data link wirelessly communicates with the content receiver to control the content receiver and receive a unique identification code from the content receiver. The wireless communications device also has its own unique identification code. The wireless communications device transmits an activation request message over a long range wireless communications link to a control station. The activation request message contains the receivers unique identification code and the communications device's own unique identification code. The control station maintains a database of valid identification codes that is used to authenticate the request. If the control station receives a valid request, an activation signal is sent to the receiver to allow operation of the receiver. | 05-15-2014 |
20140129894 | Efficient, Programmable and Scalable Low Density Parity Check Decoder - Novel design of an LDPC decoder suitable for a range of code-block sizes and bit-rates, also suitable for both ASIC and FPGA implementations, is provided, in which the overhead associated with correction data sent along the transmission channel can be minimized. An LDPC decoder can be optimized for either eIRA based or general H matrices. An H parity matrix can be constructed and/or manipulated to arrange the bit-node message “columns” to facilitate mapping to MPB “columns” and corresponding access via LUT pointer tables to minimize processing cycles so as to: (i) minimize address conflicts within the same MPB that will take multiple access cycles to resolve; (ii) minimize splitting of bit-node messages across MPB “columns” that will take multiple access cycles to resolve; and (iii) balance the bit-node computations across all the MPB/LUT “columns” so that they will complete their computations at nearly the same time. | 05-08-2014 |
20140129016 | SYSTEMS AND METHODS FOR IMPLEMENTING DYNAMIC BANKS OF SUBCHANNELS FOR BROADCAST OR STREAMED CONTENT SERVICES FEATURED FAVORITES - Systems and methods are presented for a broadcast or streamed content receiver to receive a plurality of program channels with defined banks of subset channels, to display the banks on the radio receiver, and to receive dynamic updates of both channels within the banks and the content of each such channel. In exemplary embodiments of the present invention, the channels in a given bank can be determined by commonality as to defined categories, user interest, user preferences, and/or content provider, or seasonal or other relevance. In exemplary embodiments of the present invention, channels in one or more defined banks can be buffered to facilitate smart user scanning within such defined banks, or one or more banks can be used to generate a bank specific “TuneMix™” channel. | 05-08-2014 |
20140099879 | Hybrid Satellite and Internet Mobile Broadcast System - Satellite audio and video broadcasting systems for concurrent, near-simultaneous broadcast to mobile and fixed receivers of satellite broadcast audio information and of internet streaming of at least the same audio information, and of video and data information, too. | 04-10-2014 |
20140089965 | SYSTEM FOR INSERTION OF LOCALLY CACHED INFORMATION INTO A RECEIVED BROADCAST STREAM - A method and apparatus are provided for receiving a broadcast comprising a plurality of program channels and generating a playback stream using at least one of a buffered program channel and stored indexed content (e.g., commercials, programs, songs) for insertion. Control data controls which receivers insert which indexed content and when the indexed content is inserted into a received program channel, allowing for playback of songs from playlists, tiered subscription services, and sponsorship of broadcast program channels to provide market-directed content to selected receivers and listeners. Buffer management operations prevent uncontrolled buffer growth and commercial content avoidance through rapid channel changes. | 03-27-2014 |
20130309986 | METHOD AND APPARATUS FOR ENHANCED PLAYBACK OF CONTENT WHILE SWITCHING AMONG CHANNELS OF BROADCAST OR STREAMED CONTENT WHILE BEING RECEIVED - A system and method provide an enhanced listening experience for a user of a radio receiver or other device that receives broadcast or streamed content having a plurality of program channels. The method and system buffer designated channels at the receiver and, when switching among channels, play back the buffered designated channels during reception from a selected point therein depending on the channel or other criteria. When switching to a different channel during reception, a user is able to hear content in a buffered program channel with music from the start of a song, for example, whereas content in a channel with news, talk radio, or live sports is played back from live reception, even though the content segments are transmitted at different start times relative to their selected times for playback following a channel change. User controls allow navigation among buffered designated channels during reception. | 11-21-2013 |
20130231070 | Radio Preset Key Assignmenrt Method and Apparatus - A system and method for assigning received channels to preset tuning keys of a receiver. A series of preset keys are sequentially labeled and one preset key, such as the preset key marked “0,” is a pre-defined preset key. An elongated pressing of the pre-defined key causes the currently tuned channel, if it is not assigned to a preset key, to be assigned to an unassigned preset key. If the currently tuned channel is already assigned to a preset key, pressing the pre-defined key instead causes the currently selected channel to be un-assigned from that preset key. Radios with two tuners that each process different sets of radio signals assign channels for a particular tuner to alternating preset keys, allowing acceleration of sequentially selecting channels assigned to pre-set keys by pre-tuning another tuner to the next channel in the sequence. | 09-05-2013 |
20130226369 | PORTABLE VEHICLE TELEMATICS SYSTEMS AND METHODS - A portable sensing and telematics device senses one or more conditions with respect to a vehicle and/or its occupant(s) and can communicate regarding, or in response to, the sensed condition to a remote entity (e.g., emergency responders, law enforcement agencies, other entities that monitor vehicle occupants or usage). An exemplary device can be integrated in, for example, a cigarette lighter adapter (CLA) configured to be connected to a vehicle cigarette lighter socket or auxiliary power socket. The portable sensing and telematics device can be connected to a tethered smartphone, interface with an in-vehicle modem or cellular phone, or incorporate smartphone or similar functionality within. Other form factors are possible. An exemplary device can be used in a wide variety of emergency sensing and response applications, as well as various monitoring applications and scenarios. | 08-29-2013 |
20130215984 | Overlay Modulation Technique for COFDM Signals Based on Amplitude Offsets - Systems and methods are presented for transmitting additional data over preexisting differential COFDM signals by changing the amplitude of the legacy data symbols. In exemplary embodiments of the present invention, additional data capacity can be achieved for a COFDM signal which is completely backwards compatible with existing legacy satellite broadcast communications systems. In exemplary embodiments of the present invention, additional information can be overlaid on a legacy COFDM signal by applying an amplitude offset to the legacy symbols. In exemplary embodiments of the present invention, special receiver processing can be implemented to extract this additional information, which can include performing channel equalization across frequency bins to isolate the amplitude modulated overlay signal. For example, at each FFT symbol time, average power across neighboring active data bins can be used to determine the localized power at the corresponding FFT bins, and a channel inversion can then, for example, be performed on the data bins to restore, as best as possible, the original transmitted symbol amplitude. | 08-22-2013 |
20130166984 | Efficient Implementation to Perform Iterative Decoding with Large Iteration Counts - Systems and methods are presented to improve the performance of a constant bit rate iterative decoder by providing elastic buffering, while utilizing a relatively simple decoder architecture capable of maintaining a fixed number of iterations of a lower value. An LDPC decoder can be designed, for example, to support less than the maximum possible number of iterations, and can, for example, be mated to elastic input and output buffers. If a given code block, or succession of code blocks, requires the maximum number of iterations for decoding, the decoder can, for example, run at such maximum number of iterations and the elastic input buffer can, for example, hold code blocks waiting to be processed so as to maintain a constant input rate. Alternatively, if one or more code blocks requires less than the nominal number of iterations, the output buffer can store those code blocks so as to preserve a constant output rate. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, and is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims. | 06-27-2013 |
20130121350 | Overlay Modulation of COFDM Using Phase and Amplitude Offset Carriers - Systems and methods are presented for transmitting additional data over preexisting differential COFDM signals by modulating existing data carriers with a phase and an amplitude offset. In exemplary embodiments of the present invention, additional data capacity can be achieved for an COFDM signal which is completely backwards compatible with existing satellite broadcast communications systems. In exemplary embodiments of the present invention additional information can be overlayed on an existing signal as a combination of amplitude and phase offset from the original QPSK symbols, applied for each information bit of the overlay data. With two additional levels of modulation, a receiver can demodulate the information from each of the previous stages and combine the information into a suitable format for soft decoding. The first stage of demodulation will be recovery of overlay data from the amplitude modulated D8PSK. Because other amplitude variations due to multi-path are also expected, the data gathered from the FFT in the receiver must be equalized to the channel conditions. After channel equalization has been performed, soft overlay data can then be derived from the distance off the unit circle. In order to recover the phase modulated overlay data, the equalized symbols must first be differentially demodulated and corrected for any common phase error offset. After common phase removal, overlay phase information can be obtained. | 05-16-2013 |
20130059525 | Methods and Apparatus for Interoperable Satellite Radio Receivers - Methods and apparatus are presented to allow one receiver architecture to be used for the reception of two different SDARS signals. Common receiver functions can be utilized to process each signal, thereby obviating the need to duplicate hardware elements. For example, it can be assumed that both signals will not be received at the same time, thus allowing for considerable hardware reuse and lowering the cost of an interoperable receiver. | 03-07-2013 |
20120264366 | COMPUTER BASED MULTI-CHANNEL RADIO SYSTEM AND USER INTERFACE - A computer based multi-channel radio system ( | 10-18-2012 |
20110118966 | Traffic data services without navigation systems - A non-navigation data system for providing traffic data service in a mobile environment can include a data decoder for decoding a digital data stream from a digital audio radio transmission source, location determining means (such as GPS or cellular location determining schemes) for determining a current location of a mobile receiver receiving the digital data stream, a display for displaying traffic data corresponding to the current location, and a plurality of static maps wherein the traffic data corresponding to the current location is overlaid at least over a portion of the static maps. | 05-19-2011 |
20110015856 | FUEL EQUIVALENCY FOR DATA SERVICES - A fuel information data service system is presented. In exemplary embodiments of the present invention a fuel information data service can include a controller operable to receive information regarding costs of various types of fuel, and to correlate such costs of fuel information to actual operating costs for a given vehicle, based on a known consumption efficiency for a plurality of types of fuel for that vehicle, to calculate a FuelEQ or fuel equivalency for each fuel offering. In exemplary embodiments of the present invention an exemplary system can further include a presentation device coupled to the controller where the controller is further operable to present such FuelEQ information expressed as a cost per distance traveled. In exemplary embodiments of the present invention a location finding module can be provided, and in addition to displaying various fuel costs and corresponding FuelEQ values, a fuel data system can also display distance and direction data for each available fueling station to a user. In exemplary embodiments of the present invention such a location finding system can send navigational directions to a selected fuel station based on a user selection. In exemplary embodiments of the present invention an exemplary system can alert a user when the vehicle is low on gas and has passed within a predetermined distance to a refueling station with a price lower than a threshold Fuel EQ value (value of cost per distance for fuel) set by the user. In exemplary embodiments of the present invention a navigation system can be used as a location finding module, to both determine distances and direction to a variety of local fueling or energy stations, as well as to calculate and display navigational directions to a selected fuel station in response to a user selection. | 01-20-2011 |
20100304663 | Time-varying indirect service authorization method and apparatus - Apparatus and methods for providing both commercial-free content and commercially sponsored content in a flexible manner to various subscriber classes of digital audio radio are presented. In exemplary embodiments of the present invention, lower tier subscribers can, for example, sample commercial free content as experienced by higher tier subscribers by means of flexible channel authorization. In exemplary embodiments of the present invention new non-subscribers can be allowed to sample some of the commercial content (such as, when, for example, a default UPC is stored in the radio before shipment) before choosing to subscribe. In exemplary embodiments of the present invention, a digital audio radio (receiver) can include a controller operable to receive and store an Uplink Package Code (UPC) in the digital audio radio. The radio can be further operable to receive, for example, a broadcast Package Definition Message (PDM) that maps the stored UPC to a list of authorized channels (obtained via a broadcast Package Authorization List (PAL)) for that receiver. In exemplary embodiments of the present invention, a method of channel authorization for digital audio radios can include assigning an Uplink Package Code (UPC) to, and storing the UPC in, a digital audio radio and receiving a broadcast Package Definition Message (PDM) that maps the UPC to a list of authorized channels (from a Package Authorization List (PAL)). | 12-02-2010 |
20100106514 | Travel related services via SDARS - Systems and methods of for providing various services, such as parking services, flight services, and fuel services, to a user using a satellite digital audio radio system are provided. Each data service can be provided independently or in any combination to a user, and each can be independently subscribed to by a user, in various exemplary business models. In exemplary embodiments of the present invention, a parking data service, providing, for example, information on parking garages near a certain location and the availability of parking spaces in parking garages can be provided. In exemplary embodiments of the present invention, a flight data services, providing, for example, information such as near real-time updates to changes in arrival and departure statuses of one or more commercial airline flights. In exemplary embodiments of the present invention, a fuel data service, providing, for example, information on fueling stations and the prices and fuel types available at fueling stations, can be provided. In exemplary embodiments of the present invention, such data services can be embedded in an SDARS data stream and made available to users on an SDARS receiver. | 04-29-2010 |
20100064199 | Efficient, programmable and scalable low density parity check decoder - In exemplary embodiments of the present invention, methods and apparatus allowing for an efficient design of an LDPC decoder suitable for a range of code-block sizes and bit-rates, which is also suitable for both ASIC and FPGA implementations, are provided. In exemplary embodiments of the present invention, the overhead associated with correction data sent along the transmission channel can be minimized. In exemplary embodiments of the present invention, an LDPC decoder is suitable for both ASIC and FPGA implementations. Method and apparatus allowing for an efficient design of an LDPC decoder suitable for a range of code-block sizes and bit-rates are presented. In exemplary embodiments of the present invention, such an LDPC decoder can be implemented in both ASIC and FPGA implementations. In exemplary embodiments of the present invention such an LDPC decoder can be optimized for either eIRA based H matrices or for general H matrices, as may be desirable. In exemplary embodiments of the present invention, an H parity matrix can be constructed and/or manipulated to arrange the bit-node message “columns” to facilitate mapping to MPB “columns” and corresponding access via LUT pointer tables to minimize processing cycles so as to, for example: (i) minimize address conflicts within the same MPB that will take multiple access cycles to resolve; (ii) minimize splitting of bit-node messages across MPB “columns” that will take multiple access cycles to resolve; and (iii) balance the bit-node computations across all the MPB/LUT “columns” so that they will complete their computations at nearly the same time. | 03-11-2010 |
20100008289 | Method to Minimize Interference into Legacy SDARS Reception by Varying Overlay Modulation as a Function of Satellite Position - In exemplary embodiments of the present invention, a degree of hierarchical modulation can be varied as a function of satellite position, which can be related to time of day, and where such hierarchical modulation can be a combination of phase and amplitude shifts. In exemplary embodiments of the present invention, as each satellite in a multiple satellite system broadcasting to North America moves towards a D-node or an A-node position, the offset angle of a phase-based hierarchical modulation scheme can be varied. Thus, in exemplary embodiments of the present invention, the lowest satellite position in the sky can have the lowest offset angle for overlay bits, which offset angle can, for example, progressively increase as the position of the satellite in the sky increases. At a satellite's highest point in the sky, the overlay offset angle can, for example, thus be at its maximum. To aid a receiver to receive such varying overlay modulated data, the value of a varying overlay offset angle (for each satellite) can be embedded in an Overlay Identification Marker (OIM) in the bit stream broadcast by that satellite. In exemplary embodiments of the present invention each satellite broadcast receiver can thus decode each satellite's signal, knowing its respective instantaneous overlay offset angle. The receiver can then use this information to appropriately correct MRC weightings (weighting more heavily the (higher lying) satellite with the higher degree of Layer 2 modulation) before it is MRC combined across various received signal streams. Similar methods can be implemented for other overlay modulation techniques, and the method can be extended to a broadcast system using N satellites, each having a varying degree of Layer 2 modulation. | 01-14-2010 |
20090323872 | Interface between a switched diversity antenna system and digital radio receiver - Methods and apparatus are presented for a digital radio receiver using antenna to receive a signal or signals using at least one other method of diversity. In exemplary embodiments of the present invention, both switched antenna diversity and at least one other method of diversity can be utilized in a digital radio broadcast system. In exemplary embodiments of the present invention the timing of an antenna control signal in a receiver can be synchronized so that switchover to a different receiving antenna can occur between adjacent blocks of data being received from whichever of the other diversity sources is then, on average, providing the better reception. For digitally coded transmissions, a clock signal can be provided by a signal processor so as to trigger a diversity controller to switch at an optimum switching time, such as, for example, between groups or “blocks” of digitally encoded information, thus eliminating or minimizing disruption of a contiguous data stream. | 12-31-2009 |
20090285155 | SYSTEMS AND METHODS FOR TRANSMITTING AND RECEIVING ADDITIONAL DATA OVER LEGACY SATELLITE DIGITAL AUDIO RADIO SIGNALS - Systems and methods for transmitting and receiving additional data, such as video data, over legacy satellite digital audio radio signals are provided. In exemplary embodiments, hierarchical modulation can be used to transmit secondary information over a legacy signal. For example, the Sirius Satellite Digital Audio Radio Service (“SDARS”) system may use a second layer of modulation to transmit video data on top of its regular audio signal. In order to support such future services within the original system design, sometimes referred to herein as a “legacy” system, additional information bandwidth can be acquired, for example, by using hierarchical modulation to overlay data for such new services on top of the legacy transmission. In such a system, for example, overlay data can be transmitted by applying a programmable angular offset to legacy QPSK symbols, for forming a new constellation similar to 8PSK. | 11-19-2009 |
20090279418 | OVERLAY MODULATION OF COFDM USING PHASE AND AMPLITUDE OFFSET CARRIERS - Systems and methods are presented for transmitting additional data over preexisting differential COFDM signals by modulating existing data carriers with a phase and an amplitude offset. In exemplary embodiments of the present invention, additional data capacity can be achieved for an COFDM signal which is completely backwards compatible with existing satellite broadcast communications systems. In exemplary embodiments of the present invention additional information can be overlayed on an existing signal as a combination of amplitude and phase offset from the original QPSK symbols, applied for each information bit of the overlay data. With two additional levels of modulation, a receiver can demodulate the information from each of the previous stages and combine the information into a suitable format for soft decoding. The first stage of demodulation will be recovery of overlay data from the amplitude modulated D8PSK. Because other amplitude variations due to multi-path are also expected, the data gathered from the FFT in the receiver must be equalized to the channel conditions. After channel equalization has been performed, soft overlay data can then be derived from the distance off the unit circle. In order to recover the phase modulated overlay data, the equalized symbols must first be differentially demodulated and corrected for any common phase error offset. After common phase removal, overlay phase information can be obtained. | 11-12-2009 |
20090245087 | Slow Speed Mute Resistance Via Selective COFDM Bin Loading - Systems and methods are presented for improving the ability to withstand slow speed mute via diversity transmission while avoiding loss in link level margin. In exemplary embodiments of the present invention, systems and methods are presented for improving resistance to slow speed muting by employing transmit diversity where a second signal is not a replica of the original signal. The second signal can be generated, for example, by using only a COFDM FFT bin that contained the cluster sync bit while setting all other bins to zero. That is, only the spectral portion of interest of the COFDM signal need be utilized. In such exemplary embodiments, the same frequency and time delay offset can be used as in current systems and methods, except that the replica COFDM signal can, for example, consist of only one populated FFT bin. | 10-01-2009 |
20090172492 | Method and apparatus for interleaving low density parity check (LDPC) codes over mobile satellite channels - Systems, methods and apparatus are described to interleave LDPC coded data for reception over a mobile communications channel, such as, for example, a satellite channel. In exemplary embodiments of the present invention, a method for channel interleaving includes segmenting a large LDPC code block into smaller codewords, randomly shuffling the code segments of each codeword and then convolutionally interleaving the randomly shuffled code words. In exemplary embodiments of the present invention, such random shuffling can guarantee that no two consecutive input code segments will be closer than a defined minimum number of code segments at the output of the shuffler. In exemplary embodiments of the present invention, by keeping data in, for example, manageable sub-sections, accurate SNR estimations, which are needed for the best possible LDPC decoding performance, can be facilitated based on, for example, iterative bit decisions. | 07-02-2009 |
20090168809 | METHOD AND APPARATUS TO JOINTLY SYNCHRONIZE A LEGACY SDARS SIGNAL WITH OVERLAY MODULATION - Methods and apparatus are presented for the joint synchronization of legacy signals with overlay modulation signals in a communications system utilizing a hierarchical modulation scheme. In exemplary embodiments of the present invention, a synchronization signal can be sent in each of the legacy and overlay bit streams, each using a different approach to frame synchronization, and the two synchronization signals can be used in a complementary manner to synchronize both bit streams. In exemplary embodiments of the present invention a legacy physical frame and an overlay physical frame can be aligned in time. In exemplary embodiments of the present invention a key synchronization signal in a legacy bit stream can be time distributed throughout a legacy transmission frame and can be utilized to assist in both the synchronization of such legacy bit stream and of an overlay bit stream. Additionally, in exemplary embodiments of the present invention, a key synchronization signal in an overlay bit stream can be sent in one fixed physical frame of an overlay transmission frame, and can be utilized to assist in the synchronization of such overlay bit stream as well as legacy data, in a manner that complements the use of the synchronization signal provided in the legacy bit stream. | 07-02-2009 |
20090161777 | Overlay Modulation Technique for COFDM Signals Based on Amplitude Offsets - Systems and methods are presented for transmitting additional data over preexisting differential COFDM signals by changing the amplitude of the legacy data symbols. In exemplary embodiments of the present invention, additional data capacity can be achieved for a COFDM signal which is completely backwards compatible with existing legacy satellite broadcast communications systems. In exemplary embodiments of the present invention, additional information can be overlaid on a legacy COFDM signal by applying an amplitude offset to the legacy symbols. In exemplary embodiments of the present invention, special receiver processing can be implemented to extract this additional information, which can include performing channel equalization across frequency bins to isolate the amplitude modulated overlay signal. For example, at each FFT symbol time, average power across neighboring active data bins can be used to determine the localized power at the corresponding FFT bins, and a channel inversion can then, for example, be performed on the data bins to restore, as best as possible, the original transmitted symbol amplitude. | 06-25-2009 |
20090161025 | METHODS AND SYSTEMS FOR FAST CHANNEL CHANGE BETWEEN LOGICAL CHANNELS WITHIN A TRANSPORT MULTIPLEX - A system, method and computer program product are provided for fast channel change between logical channels within a transport multiplex. By reducing the amount of time it takes to acquire and display a tuned channel, fast channel change can improve a viewer's experience. In exemplary embodiments of the present invention, a fast channel change system can simultaneously decode channel data for each channel in a transport multiplex, reconstruct all access units for each channel and send them out on their respective channel stream in the order that each access unit completes to a streamer, store and maintain a minimum amount of channel data in a buffer in each streamer, and output channel data from a streamer corresponding to a tuned channel to a media player. In exemplary embodiments of the present invention data can be input to a de-multiplexer and divided into separate video and audio streams prior to being input to the media player. Exemplary embodiments of the present invention can be utilized in various video applications, such as, for example, Sirius Satellite Radio's Backseat TV™ service. | 06-25-2009 |