Abstract: Downstream synchronous multichannel (DSSM) communications are provided among a plurality of carriers, each being a completely DOCSIS™ 2.0-compliant downstream. The synchronous multichannels support communications with both DSSM-capable communications nodes and non-DSSM-capable communications nodes (e.g., legacy cable modems). Non-DSSM packets are transmitted on a single channel. DSSM packets are split into multiple pieces, which are transmitted simultaneously on all available channels. Since the physical delay variation (e.g., group delay change) across the adjacent carriers is small (on the order of a symbol time), the multiple pieces arrive at the receiving communications nodes at nearly the same time and can be reassembled with minimal buffering and no packet ordering problems. To avoid causing trouble for the non-DSSM-capable communications nodes, the packet pieces are encapsulated with a header that causes the non-DSSM-capable communications nodes to silently discard them.

Abstract: Downstream synchronous multichannel (DSSM) communications are provided among a plurality of carriers, each being a completely DOCSIS™ 2.0-compliant downstream. The synchronous multichannels support communications with both DSSM-capable communications nodes and non-DSSM-capable communications nodes (e.g., legacy cable modems). Non-DSSM packets are transmitted on a single channel. DSSM packets are split into multiple pieces, which are transmitted simultaneously on all available channels. Since the physical delay variation (e.g., group delay change) across the adjacent carriers is small (on the order of a symbol time), the multiple pieces arrive at the receiving communications nodes at nearly the same time and can be reassembled with minimal buffering and no packet ordering problems. To avoid causing trouble for the non-DSSM-capable communications nodes, the packet pieces are encapsulated with a header that causes the non-DSSM-capable communications nodes to silently discard them.

Abstract: Embodiments of a digital up-converter and an N-channel modulator are provided herein. The embodiments of the digital up-converter, in combination with the N-channel modulator, are capable of efficiently filling the spectrum of one or more RF signals with one or more types of information signals. For example, the digital up-converter can fill the spectrum of one or more RF signals with both broadcast and narrowcast video and data signals. In addition, the digital up-converter is capable of flexibly mapping the information signals to one or more channels of the one or more RF signals using a novel, three-level switching architecture.

Abstract: A system and method are used to provide uncorrelated code hopping in a communications system. A shift register receives data. The shift register is clocked to shift the data. A scaler performs a scaling operation on the data with a numerical value of active codes. A truncator truncates the scaled data to its seven most significant bits to produce a pseudo random hop number. A code matrix shifter circularly shifts the active codes in a code matrix based on the pseudo random hop number to produce a circularly shifted code. A transmitter transmits the circularly shifted code.

Abstract: A cable modem communication system includes a plurality of Cable Modems (CMs), a CM network segment, and a Cable Modem Termination System (CMTS). The CMTS segregates the plurality of CMs into a first group of CMs with which standard registering and ranging operations are performed and a second group of CMs with which attenuated transmission registering and ranging operations are performed. Each CM of the first group of CMs operable to perform registering and ranging operations by transmitting a ranging burst of a first format. Each CM of the second group of CMs operable to perform registering and ranging operations by transmitting a ranging burst of a second format that differs from the ranging burst of the first format. The CMTS may include a rake receiver that receives and demodulates a plurality of multi-path copies of the ranging burst of the second format.

Abstract: Embodiments herein provide systems and methods of transferring data in a communication system. An embodiment transfers data by assigning a portion of data among groups of channels coupled to a remote node, such assigning being based on the respective flows to which the portion is associated. The portion of data across is at least two channels in the assigned group of channels, and the split portions are transferred substantially simultaneously among the channels to which they are assigned.

Abstract: A communication system that includes a supervisory node (e.g., a headend) and one or more remote nodes (e.g., cable modems). Packets are transmitted between the supervisory node and the one or more remote nodes via RF channels. A plurality of the RF channels are bonded, such that packets may be transmitted via any one or more of the RF channels that are bonded. Bonding may include higher-layer bonding and/or lower-layer bonding. In higher-layer bonding, the communication system further includes a forwarder and a plurality of edge modulators. Each edge modulator is connected to a different RF channel or group of RF channels. The forwarder determines to which edge modulator one or more packets or flows are to be transmitted. In lower-layer bonding, a packet is split into pieces. The pieces are assigned to respective RF channels that are associated with an edge modulator for transmission to a remote node.

Abstract: A system and method are used to provide uncorrelated code hopping in a communications system. A shift register receives data. The shift register is clocked to shift the data. A scaler performs a scaling operation on the data with a numerical value of active codes. A truncator truncates the scaled data to its seven most significant bits to produce a pseudo random hop number. A code matrix shifter circularly shifts the active codes in a code matrix based on the pseudo random hop number to produce a circularly shifted code. A transmitter transmits the circularly shifted code.

Abstract: A distributed cable modem termination system of the present invention includes a downstream transmitter hub, an upstream receiver hub, and a head end that communicatively couples to the downstream transmitter hub and to the upstream receiver hub via a packet data network. The head end and the downstream transmitter hub are operable to synchronize a clock of the downstream transmitter hub with a clock of the head end. Further, the upstream receiver hub and the downstream transmitter hub are operable to synchronize a clock of the upstream receiver hub with the clock of the downstream transmitter hub. Clock synchronization between the upstream receiver hub and the downstream transmitter hub are performed using ranging operations supported by at least one cable modem communicatively coupled to both the upstream receiver hub and the downstream transmitter hub via cable modem network plant.

Abstract: A system and method are used to provide uncorrelated code hopping in a communications system. A multi-bit linear shift register receives data and clocks the data fifteen times. A word assembler receives the shifted data and outputs a fifteen bit word. A mixer mixes the fifteen bit word with an numerical value of active codes to generate a mixed signal. A divider divides the mixed signal to produce a divided signal. A truncator truncates the divided signal to its seven most significant bits to produce a pseudo random hop number. A code matrix shifter circularly shifts the active codes in a code matrix based on the pseudo random hop number to produce a circularly shifted code. A transmitter transmits the circularly shifted code matrix.

Abstract: Downstream synchronous multichannel (DSSM) communications are provided among a plurality of carriers, each being a completely DOCSIS™ 2.0-compliant downstream. The synchronous multichannels support communications with both DSSM-capable communications nodes and non-DSSM-capable communications nodes (e.g., legacy cable modems). Non-DSSM packets are transmitted on a single channel. DSSM packets are split into multiple pieces, which are transmitted simultaneously on all available channels. Since the physical delay variation (e.g., group delay change) across the adjacent carriers is small (on the order of a symbol time), the multiple pieces arrive at the receiving communications nodes at nearly the same time and can be reassembled with minimal buffering and no packet ordering problems. To avoid causing trouble for the non-DSSM-capable communications nodes, the packet pieces are encapsulated with a header that causes the non-DSSM-capable communications nodes to silently discard them.

Abstract: Downstream synchronous multichannel (DSSM) communications are provided among a plurality of carriers, each being a completely DOCSIS™ 2.0-compliant downstream. The synchronous multichannels support communications with both DSSM-capable communications nodes and non-DSSM-capable communications nodes (e.g., legacy cable modems). Non-DSSM packets are transmitted on a single channel. DSSM packets are split into multiple pieces, which are transmitted simultaneously on all available channels. Since the physical delay variation (e.g., group delay change) across the adjacent carriers is small (on the order of a symbol time), the multiple pieces arrive at the receiving communications nodes at nearly the same time and can be reassembled with minimal buffering and no packet ordering problems. To avoid causing trouble for the non-DSSM-capable communications nodes, the packet pieces are encapsulated with a header that causes the non-DSSM-capable communications nodes to silently discard them.

Abstract: A modulation and demodulation scheme for video signals may be used for HDTV signals using VSB-PAM, analog NTSC signals using VSB-AM and digital video signals using QAM. VSB-PAM modulation and demodulation may be performed using in-phase and quadrature baseband filters. By adjusting the filter taps, a single modulator structure may be used for QAM and VSB-PAM modulation. Similarly, a single demodulator structure may be used for QAM and VSB-PAM demodulation. This demodulator may also be used for VSB-AM modulation.

Abstract: A communication method enables a plurality of remote locations to transmit data to a central location. The remote locations simultaneously share a channel and there is a high degree of immunity to channel impairments. At each remote location, data to be transmitted is coded by translating each group of one or more bits of the data into a transform coefficient associated with a frequency in a particular subset of orthonormal baseband frequencies allocated to each remote location. The particular subset of orthonormal baseband frequencies allocated to each location is chosen from a set of orthonormal baseband frequencies. At each remote location, an electronic processor performs an inverse orthogonal transform (e.g., an inverse Fourier Transform) on the transform coefficients to obtain a block of time domain data. The time domain data is then modulated on a carrier for transmission to the central location.

Abstract: A method and apparatus for detecting a maximum vertical frequency component in a received interlaced transmission and substituting therefore, a uniform zero vertical frequency component in order to form a sequential scan display without introducing motion induced artifacts.

Abstract: A vertical filter for filtering digital television signals in which the length of the filter may be greater than the decimation factor. The vertical filter includes a first and a second multiplier-accumulator section each having a multiplier for receiving each line in the digital television signal and for multiplying each line by a respective filter coefficient, a switch having a first input connected to an output of the multiplier, a line delay circuit connected to an output of the switch, and an adder circuit connected to the output of the multiplier and the line delay circuit. The vertical filter further includes a multiplexer connected to the outputs of the first and second multiplier-accumulator sections for alternatively applying the outputs of the first and second multiplier-accumulators to the output of the filter.