Abstract: Fiber, cable, and wireless data channels are typically impaired by reflectors and other imperfections, producing a channel state with echoes and frequency shifts in data waveforms. Here, methods of using OTFS pilot symbol waveform bursts to automatically produce a detailed 2D model of the channel state are presented. This 2D channel state can then be used to optimize data transmission. For wireless data channels, an even more detailed 2D model of channel state can be produced by using polarization and multiple antennas in the process. Once 2D channel states are known, the system turns imperfect data channels from a liability to an advantage by using channel imperfections to boost data transmission rates. The methods can be used to improve legacy data transmission modes in multiple types of media, and are particularly useful for producing new types of robust and high capacity wireless communications using non-legacy OTFS data transmission methods.

Abstract: Distributed and highly software reconfigurable CMTS (CMRTS) device, based on MAC and PHY units with FPGA and DSP components, for a HFC CATV network. The various CATV RF modulators, such as QAM modulators, may be divided between QAM modulators located at the cable plant, and remote QAM modulators ideally located at the fiber nodes. A basic set of CATV QAM data waveforms may optionally be transmitted to the nodes using a first fiber, and a second set of IP/on-demand data may be transmitted to the nodes using an alternate fiber or alternate fiber frequency, and optionally using other protocols such as Ethernet protocols. The nodes will extract the data specific to each neighborhood and inject this data into unused QAM channels, thus achieving improved data transmission rates through finer granularity. A computerized “virtual shelf” control system for managing and reconfiguring the FPGA and DSP based CMTRS units is also disclosed.

Abstract: A method of receiving data including receiving, on one or more carrier waveforms, signals representing a plurality of data elements of an original data frame wherein each of the data elements are represented by cyclically time shifted and cyclically frequency shifted versions of a known set of waveforms. The method further includes generating, based upon the signals, a received data frame and generating an equalized data frame by performing an equalization operation using elements of the received data frame, the equalization operation correcting for distortion introduced into the signals during propagation of the carrier waveforms through a channel.

Abstract: A method to extend the downstream and upstream data carrying capability of an HFC CATV system. At the neighborhood level, the CATV cable (the primary channel) is divided into different segments connected by electrically active junctions. At the junctions, each segment is also connected to a secondary data channel, such as an optical fiber or ultrahigh RF frequency (1 GHz+) secondary channel, which can carry supplemental downstream narrowcast channels and upstream channels between a plurality of such CATV cable segments. At the junctions, some CATV primary channel RF signals such as broadcast channels are passed without interference, while certain primary channel downstream narrowcast RF channels and upstream narrowcast RF channels are precisely suppressed using adaptive cancelling methods. Such adaptive cancellation methods are superior to prior art lowpass, highpass, and bandpass filtering methods because they allow for more efficient use of limited CATV primary channel RF spectrum.

Abstract: Producing advanced HFC CATV cable systems while easing the burden of backward compatibility. The system improves CATV data carrying capacity by moving RF QAM modulators from the cable head end to various individually or group addressed optical fiber nodes supplying neighborhood CATV cables, and sending data from the cable head IP backbone to the nodes over optical fiber as IP data packets. For high backward compatibility, the system digitizes legacy RF waveforms, or demodulates legacy QAM waveforms to QAM symbols, also transmits these over the optical fiber as IP data packets, and then reconstitutes back to original waveforms as needed. The system is thus able to easily handle legacy NTSC, FM, QPSK waveforms and do partial (QAM symbol level) compression of legacy QAM waveforms to and from multiple nodes without requiring additional optical fiber wavelengths. The system may use non-standard upstream/downstream CATV frequency splits, filter bank receivers, and FPGA/DSP/ASIC methods.

Abstract: A system and method of providing a modulated signal useable in a signal transmission system. The method includes transforming, perhaps with respect to both time and frequency, a data frame including a plurality of data elements into a transformed data matrix. The transformed data matrix includes a plurality of transformed data elements where each of the plurality of transformed data elements is based upon each of the plurality of data elements. The method further includes generating the modulated signal in accordance with the transformed data elements of the transformed data matrix.

Abstract: Fiber, cable, and wireless data channels are typically impaired by reflectors and other imperfections, producing a channel state with echoes and frequency shifts in data waveforms. Here, methods of using OTFS pilot symbol waveform bursts to automatically produce a detailed 2D model of the channel state are presented. This 2D channel state can then be used to optimize data transmission. For wireless data channels, an even more detailed 2D model of channel state can be produced by using polarization and multiple antennas in the process. Once 2D channel states are known, the system turns imperfect data channels from a liability to an advantage by using channel imperfections to boost data transmission rates. The methods can be used to improve legacy data transmission modes in multiple types of media, and are particularly useful for producing new types of robust and high capacity wireless communications using non-legacy OTFS data transmission methods.

Abstract: A method for signal transmission using precoded symbol information involves estimating a two-dimensional model of a communication channel in a delay-Doppler domain. A perturbation vector is determined in a delay-time domain wherein the delay-time domain is related to the delay-Doppler domain by an FFT operation. User symbols are modified based upon the perturbation vector so as to produce perturbed user symbols. A set of Tomlinson-Harashima precoders corresponding to a set of fixed times in the delay-time domain may then be determined using a delay-time model of the communication channel. Precoded user symbols are generated by applying the Tomlinson-Harashima precoders to the perturbed user symbols. A modulated signal is then generated based upon the precoded user symbols and provided for transmission over the communication channel.

Abstract: A method of converting legacy HFC CATV cable systems, which transmit data over the optical fiber portion of the system using the optical counterpart of analog RF waveforms, such as RF QAM waveforms transduced to corresponding optical QAM waveforms, to improved HFC CATV systems that transmit data over the optical fiber using optical fiber optimized protocols, such as Ethernet frames and other optical fiber optimized digital transport protocols. According to the method, most aspects of the legacy HFC CATV system may be retained, however at the CATV head end, the optical fiber transmitter system is replaced by an improved system that extracts the underlying symbols from legacy waveforms, packages these symbols into optical fiber optimized packets, and transmits downstream. The legacy optical fiber nodes are replaced with improved nodes capable of receiving the packets and remodulating the symbols into RF waveforms suitable for injection into the system's CATV cable.

Abstract: Methods to improve the data carrying capacity of CATV DOCSIS systems and other communications systems are disclosed. Communications channels may be more efficiently spaced with reduced or absent guard bands by using receivers with adaptive signal cancellation methods, equalizing circuits, or polyphase filter banks and Fast Fourier Transform signal processing methods to correct for higher levels of cross-talk. QAM type communications channels may also be utilized on a synchronized two-transmitter at a time basis by adjusting the transmitters to predefined signal levels, such as +1, ?1, +½, ?½ to enable the combined signals to be distinguished at the receiver. These two methods may be combined to create a still higher data throughput system.

Abstract: A system and method of variable latency data transmission. The method includes transforming a first original data frame in accordance with a first time-frequency transformation so as to provide a first transformed data frame wherein the first time-frequency transformation is associated with a first latency. The method further includes transforming a second original data frame in accordance with a second time-frequency transformation so as to provide a second transformed data frame wherein the second time-frequency transformation is associated with a second latency. Using a transmitter, elements of the first transformed data frame are transmitted over a first frame period corresponding to the first latency and elements of the second transformed data frame are transmitted over a second frame period corresponding to the second latency wherein the first frame period is different from the second frame period.

Abstract: A device and method for signal separation in an orthogonal time frequency space communication system using MIMO antenna arrays. The communication device includes an antenna arrangement and a receiver. The receiver is configured to receive, from the antenna arrangement, a plurality of pilot signals associated with respective locations in a time-frequency plane wherein the plurality of pilot signals were transmitted from a corresponding plurality of transmit antenna elements. The receiver is further configured to receive signal energy transmitted by the plurality of transmit antenna elements and to measure, based upon the plurality of pilot signals, a plurality of two-dimensional time-frequency coupling channels between the plurality of transmit antenna elements and the antenna arrangement. The receiver is also operative to invert a representation of each of the plurality of two-dimensional time-frequency coupling channels to provide a plurality of inverted channel representations.

Abstract: System and method to extend the upstream data capacity of an HFC CATV system by extending a “shadow” optical fiber network deeper into the various CATV cable neighborhoods, with coax fiber terminals (CFT) spaced roughly according to the distribution of CATV active devices such as RF amplifiers. The CFT can intercept local upstream data from various neighborhood sub-regions and transform this upstream data into upstream optical data, thus relieving upstream data congestion in the 5-42 MHz CATV frequency region. The system can produce an order of magnitude improvement in upstream capability, while maintaining high compatibility with legacy HFC equipment. The CFT may exist in multiple embodiments ranging from low-cost “dumb” CFT to sophisticated CFT that can additionally provide GigE to the home (GTTH) service. Methods to maintain good compatibility with legacy CMTS devices, and methods to utilize DOCSIS MAP data for more efficient data transmission are also discussed.

Abstract: Distributed CMTS device for a HFC CATV network serving multiple neighborhoods by multiple individual cables, in which at least some and often all of the QAM modulators that provide data for the individual cables are remote QAM modulators ideally located at the fiber nodes. A CCAP set of IP/on-demand data is transmitted to the nodes using an optical fiber, often using digital protocols such as Ethernet protocols. Optionally a basic set of legacy CATV QAM data, transmitted using RF waveforms transposed to optical frequencies, may also be transmitted to the nodes using either the same or different optical fiber. The nodes extract the data specific to each neighborhood, and inject this data into unused cable QAM channels along with any optional legacy CATV QAM waveforms as desired, thus achieving improved data transmission rates through finer granularity. A computerized “virtual shelf” control system for this system is also disclosed.

Abstract: Fiber, cable, and wireless data channels are typically impaired by reflectors and other imperfections, producing a channel state with echoes and frequency shifts in data waveforms. Here, methods of using OTFS pilot symbol waveform bursts to automatically produce a detailed 2D model of the channel state are presented. This 2D channel state can then be used to optimize data transmission. For wireless data channels, an even more detailed 2D model of channel state can be produced by using polarization and multiple antennas in the process. Once 2D channel states are known, the system turns imperfect data channels from a liability to an advantage by using channel imperfections to boost data transmission rates. The methods can be used to improve legacy data transmission modes in multiple types of media, and are particularly useful for producing new types of robust and high capacity wireless communications using non-legacy OTFS data transmission methods.

Abstract: Computerized wireless transmitter/receiver system that automatically uses combinations of various methods, including transmitting data symbols by weighing or modulating a family of time shifted and frequency shifted waveforms bursts, pilot symbol methods, error detection methods, MIMO methods, and other methods, to automatically determine the structure of a data channel, and automatically compensate for signal distortions caused by various structural aspects of the data channel, as well as changes in channel structure. Often the data channel is a two or three dimensional space in which various wireless transmitters, receivers and signal reflectors are moving. The invention's modulation methods detect locations and speeds of various reflectors and other channel impairments. Error detection schemes, variation of modulation methods, and MIMO techniques further detect and compensate for impairments.

Abstract: A method and system for multiple access in a system utilizing two-dimensional signal modulation. The method includes spreading data symbols arranged in a two-dimensional information domain onto sets of grid points respectively associated with different users in a time-frequency domain. The spreading is performed using two-dimensional basis functions uniquely associated with positions on a lattice in the information domain corresponding to the data symbols. A modulated signal is then generated using the sets of transformed symbols. The sets of grid points associated with the different users may be interleaved within the time-frequency domain or may form non-interleaved windows.

Abstract: A system and method for receiving communication signals that have been spread in two dimensions. The method includes receiving signals representative of data that has been two-dimensionally spread and transmitted over a communication channel. The method further includes processing the signals to determine equalization coefficients based upon a two-dimensional time-frequency impulse response of the communication channel. A two-dimensional signal equalization procedure is then performed using the equalization coefficients.

Abstract: A method and apparatus for wireless communication compatible with a Long Term Evolution (LTE) communication system. The method includes transforming input data in accordance with a two-dimensional Orthogonal Time Frequency Space (OTFS) transform in order to generate OTFS transformed data. The method includes generating a data frame that contains the transformed data and is structured for use within the LTE communication system. The method further includes transmitting the data frame using an Orthogonal Frequency Division Multiplexing (OFDM) transmitter.

Abstract: Distributed and software reconfigurable remote CMTS (CMRTS) device, based on MAC and PHY units with FPGA and DSP components, for a HFC CATV network. The various CATV RF modulators, such as QAM modulators, may be located entirely at the fiber nodes if desired. Although a basic set of CATV QAM data waveforms may optionally be transmitted to the nodes using a first fiber, in a preferred embodiment, all data may be transmitted to the nodes using other protocols such as Ethernet protocols. The nodes will extract the data specific to each neighborhood and inject this data into the cable portion of the system as RF waveforms, such as RF QAM channels. A computerized “virtual shelf” control system for managing and reconfiguring the FPGA and DSP based CMTRS units, as well as a new type of edge router based all-digital virtual head end (virtual converged cable access platform) is also disclosed.