Abstract: In embodiments of the presently described subject matter, two efficient PAPR reduction methods for OFDM signals based upon the principle of tone reservation and building upon the clipping noise analysis presented in “Analysis of clipping noise and tone reservation algorithms for peak reduction in OFDM systems,” L. Wang and C. Tellambura, IEEE Trans. Veh. Technol., vol. 57, pp. 1675-1694, May 2008 are provided, each comprising two stages. The first stage is performed offline to prepare a set of cancellation signals based on the settings of the OFDM system. In particular, these cancellation signals are constructed to cancel signals at different levels of maximum instantaneous power that are above a predefined threshold. The second stage is performed online and in an iterative manner to reduce the peaks of OFDM symbols by using the cancellation signals constructed in the first stage.

Abstract: A data transfer system (100) includes a data transmission device (103). The data transmission device can include a data communication circuit (206), a memory (202), and a control circuit (201) operable with the communication circuit and the memory circuit. The control circuit can transfer data (306) to a remote device, establish a sliding window (307) spanning a predetermined amount of data, and store the predetermined amount of data. In response to receiving an error message (311) identifying particular data (312) encountering errors in transfer, the control circuit can retransfer the particular data so long as the particular data is within the sliding window.

Abstract: A remote storage digital video recording system (300) comprises a storage server (310). The storage server can include a memory (412) and a control circuit (410) operable with the memory. The storage server can be in communication across a network (311) with one or more client devices (306,307,308). The control circuit can be configured to create a file allocation table (314) to organize clusters (330) of a computer readable medium (308). The file allocation table can include a plurality of distinguishable file entries (320,321,322). Each of the distinguishable file entries can index clusters of the computer readable medium. At least two of the plurality of distinguishable file entries can index selfsame clusters (331) of the computer readable medium.

Abstract: A server complex (102) includes an interface portal (116). The server complex exposes (401) a generic resource locator (402) pointing to the media content in a generic format at the interface portal. The server complex receives requests for media content (101) from at least a first client device (601) to receive the media content in a first format (603) and at least a second client device (602) to receive the media content in a second format (604). The server complex determines (405), from a header (407) of the request, whether the request is from the first client device or the second client device, generates (409) a response message (108) comprising a manifest file (109) comprising a device specific resource locator (410) pointing to the media content cached (412) in one of the first format or the second format, and transmits (411) the response message to the requesting client.

Abstract: A system (100) includes an interface portal (116) to receive (401), at a resource locator (402) pointing to media content (101), a request (117) for the media content from a client device (109). A server complex (102) can validate a secure token (403) of the request, and can issue a new token (405) that includes one or more session identification credentials (406). These can include a session identifier (407) indicating a session required to retrieve the media content to the client device, an identifier of an edge server (105) to serve the request for the media content, and other information. A resource management system (106), operable with the server complex and the edge server, can then throttle a data rate of the session as a function of the one or more session identification credentials or terminate the session as a function of the one or more session credentials.

Abstract: In a digital communication system there is provided a method for OFDM channel estimation that jointly considers the effects of coarse timing error and multipath propagation. The method uses an iterative channel estimation technique, which considers the practical scenario of fractional timing error and non-sample space echo delays. The method does not require channel state information such as second-order statistic of the channel impulse responses or the noise power. Moreover, timing error can be conveniently obtained with the proposed technique. Simulation shows that, when comparing OFDM channel estimation techniques under DOCSIS 3.1 realistic channel conditions, the proposed algorithm significantly outperforms conventional methods.

Abstract: A method used in the receiver of a communication system is provided to suppress narrow band interferences, known as ingress, that are present in the communication channel, which is shared by a plurality of transmitters each having a channel pre-equalizer, by means of a Time Division Multiple Access (TDMA) scheme or Synchronous Code Division Multiple Access (SCDMA) scheme. The method comprises filtering the interferences using Infinite Impulse Response (IIR) notch filters, and providing IIR all-pass filters devised to compensate for substantially all phase distortions introduced by the notch filters. The method also includes an algorithm to detect the narrow band interferences and an adaptive equalizer to equalize the channel by computing the coefficients of the transmitters' pre-equalizers, and arranged such that the equalization of the channel is isolated from the suppression of the interferences.

Abstract: A method of channel processing is provided wherein multiple reduced-bandwidth “processing blocks” may be combined at RF to allow for the continuous and flexible placement of multiple-channels across the full or partial CATV output band. Each reduced-bandwidth processing block is associated with a fixed-frequency upconversion. In order to allow for continuous agile channel placement, the processing blocks overlap one another in frequency at RF. In the case where it is not necessary that the full CATV band be available to the combined output, the number of required processing blocks and upconversion paths is reduced and individual processing blocks and upconversion paths may be used to cover multiple non-contiguous frequency bands.

Abstract: In a DOCSIS transmission network, it is necessary for an upstream receiver to estimate and correct for errors in the carrier frequency of the transmission based upon observations of a preamble sequence. This task is complicated by the fact that microreflections in the upstream channels cause intersymbol interference, which tends to bias the frequency estimation circuit. An economical, ISI-immune algorithm is provided for estimating the carrier frequency of upstream transmissions. The arrangement improves the reliability of the frequency estimates in the presence of ISI, thereby reducing the overhead and increasing the throughput of the upstream channels.

Abstract: A method of channel-to-port assignment is described where the distribution of channels is performed in the digital domain of the CATV/QAM upconverter/modulator. This channel distribution allows for the possibility of simple failover, power combining of multiple outputs, and a fine granularity of channel to port mapping, QAM or analog channel, in a multi-port device.

Abstract: A distortion-cancellation method for analog CATV or QAM transmission over cable is provided wherein a single feedback path from the output of a multiple-channel multiple-port upconverter/modulator is down-converted and used to reduce or cancel undesirable noise components including LO leakage, spurious, and modulated noise. The method allows for real-time monitoring, tuning, or control of the CATV/QAM output and of interfering signals and aging effects as compared to a desired performance metric.

Abstract: In an RF signal transmission network such as the reverse channels of a coaxial cable network, there is provided at least one adaptive equalizer for pre- or post-filtering inter-symbol interference in the transmitted signals, the adaptive equalizer having a series of coefficients for which values are required. In order to improve the transmission efficiency the preamble used in these channels is shortened by coarsely estimating the channel using a short “unique word’ placed at the beginning of the equalizer training sequence. The coarse channel estimate is crudely inverted to produce a set of equalizer coefficients which partially equalize the channel. By initializing the adaptive equalizer with these approximate coefficients, it is possible to reduce the length of the training sequence needed for the equalizer to converge.

Abstract: A method is provided for reducing inter modulation distortion products using multi-carrier phase alignment of the type where a combined carrier signal is generated from the combined output carried waves of a plurality of numerically controlled oscillators in which the frequency of the carrier wave can be altered by changing an input value into the oscillator. In particular the initial phase of the output carrier waves is adjusted so that the peak amplitude of the combined carrier signal is minimized so that compression of the higher amplitude portions of the combined signal is reduced.

Abstract: Direct digital QAM modulation at an RF frequency is obtained from digitally synthesized RF signals which are generated for use as the two vectors. The two vectors are individually controlled in phase and summed to provide a combined phase and amplitude modulation that forms the modulated signal. The synthesized RF signal is generated from a higher reference frequency using a variable pulse stretching technique implemented with programmable delay lines. The amount of the pulse stretch in each cycle is controlled by a phase increment value. Pulse stretching can be extended beyond one cycle by pulse swallowing, allowing the generation of an RF signal from DC up to and including the input reference frequency. Phase modulation is added by digital control of the pulse stretching according to the phase modulation data bits.

Abstract: A method to improve the frequency resolution and phase noise of a synthesized RF signal results in superior instantaneous frequency change and phase modulation capability, wide frequency set ability, and suitability for implementation in a digital ASIC. The RF signal synthesis is achieved from a higher reference frequency clock signal using a variable pulse stretching technique. The amount of the pulse stretch in each cycle is set by a phase increment value and is implemented using programmable delay lines. Pulse stretching can be extended beyond one cycle by pulse swallowing, allowing the generation of an RF signal with frequencies from DC up to the input reference frequency. Phase modulation is incorporated by digital control of the phase stretching with the phase modulation bits.

Abstract: A system and method for data detection in a wireless communication system wherein the system comprises a receiver for receiving spatial-subspace data transmitted over a plurality of spatial-subspace channels of a sub-carrier which may comprise at least one of coded and uncoded spatial-subspace channels. The receiver comprises a receiver weighting unit for providing receive-weighed spatial-subspace data and a data estimation unit for performing an iterative processing method on the receive-weighted spatial-subspace data to estimate output data related to the input data symbol stream. The-iterative processing method comprises successively processing data on each of the plurality of spatial-subspace channels in the receive-weighted spatial-subspace data.

Abstract: A system and method for transmitting a plurality of input data symbol sub-streams over a plurality of spatial-subspace channels of a sub-carrier between a transmitter and the receiver. The plurality of input data symbol sub-streams are partitioned in a plurality of super-frames of data and weighted by a weight matrix derived from the singular value decomposition of a channel matrix corresponding to the sub-carrier by applying a partial SVD algorithm. The transmitter further inserts subspace training symbols into the plurality of input data symbol sub-streams and the receiver periodically processes the sub-space training symbols during each super-frame of the plurality of super-frames for estimating output data related to the input data symbol stream.

Abstract: A time-sliced discrete-time Phase Locked Loop which is suitable for simultaneously synchronizing multiple input signals to multiple output signals is provided by implementing a discrete-time phase detector, loop filter, and voltage controlled oscillator that together operate as a single discrete-time PLL in hardware and applying control logic to retrieve the history for each signal pair from a context memory (RAM), to enable the discrete-time PLL hardware, and to store the resulting history in the context memory for use in subsequent operations for a particular input/output signal pair.