Abstract: Successive pairs of OFDM symbols are transmitted by an OFDM transmitter and received by an OFDM receiver. The successive pairs include a first pair of OFDM symbols. First and second OFDM symbols of the first pair both include pilot symbols on two subcarriers that are symmetric about a center carrier frequency. The two subcarriers are the same for the first and second OFDM symbols. The pilot symbols on the two subcarriers for the first and second OFDM symbols compose an orthogonal matrix. The OFDM receiver estimates frequency responses at frequencies including the frequencies of the two subcarriers and compensates for signal impairment based at least in part on the estimated frequency responses.

Abstract: A receiver receives a repeating or periodic signal and, based on the signal, estimates a carrier frequency offset for the receiver. Based on the signal and the estimated carrier offset, an I/Q mismatch for the receiver is estimated and compensation for the estimated I/Q mismatch is performed. After compensating for the estimated receiver I/Q mismatch, the carrier frequency offset is re-estimated.

Abstract: A coax network unit (CNU) is coupled to a coax line terminal (CLT). In first and second modes of operation, the CNU transmits data during an upstream window and receives data during a downstream window. In the first mode of operation, a duration of data transmission for the upstream window or a duration of data reception for the downstream window is reduced by a specified amount with respect to the second mode. A sounding signal is transmitted in the first mode in a probing slot that has a duration corresponding to the specified amount.

Abstract: A coax network unit (CNU) coupled to a coax line terminal (CLT) receives a plurality of orthogonal frequency-division multiplexing (OFDM) symbols from the CLT and identifies a start-of-frame delimiter on a physical-layer (PHY) control channel in the plurality of OFDM symbols. The PHY control channel includes a plurality of contiguous subcarriers. The CNU decodes one or more forward error correction (FEC) code words that follow the start-of-frame delimiter on the PHY control channel. The one or more FEC code words provide PHY control data that include information specifying a structure of a PHY frame that includes the plurality of OFDM symbols.

Abstract: A coax network unit (CNU) receives downstream bursts from a coax line terminal (CLT) and transmits upstream bursts to the CLT. The downstream bursts include start markers that indicate the beginnings of the downstream bursts and may also include pilot symbols. The downstream bursts are continuous across available resource elements in a matrix of subcarriers and orthogonal frequency-division multiplexing (OFDM) symbols. The available resource elements exclude resource elements in the matrix that carry the pilot symbols. The upstream bursts may include start markers indicating the beginnings of the upstream bursts and end markers indicating the ends of the upstream bursts. Respective upstream bursts are transmitted in respective groups of one or more resource blocks allocated to the CNU.

Abstract: A coax network unit (CNU) receives a first plurality of orthogonal frequency-division multiplexing (OFDM) symbols from a coax line terminal (CLT). The first plurality of OFDM symbols includes continual pilot symbols on one or more subcarriers. The CNU also receives a grant from the CLT allocating a set of subcarriers within a second plurality of OFDM symbols to the CNU. The CNU transmits upstream to the CLT using the allocated set of subcarriers within the second plurality of OFDM symbols. When transmitting, the CNU places non-continual pilot symbols on regularly spaced subcarriers of the allocated set of subcarriers and does not place continual pilot symbols within the allocated set of subcarriers.

Abstract: A network device includes a plurality of physical-media entities (PMEs), each corresponding to a distinct channel, to generate transmit signals based on transmit packets received over a media-independent interface. The network device also includes a channel-bonding sublayer to direct the transmit packets from the media-independent interface to respective PMEs of the plurality of PMEs. The channel-bonding sublayer has a substantially fixed delay between the media-independent interface and the plurality of PMEs for the transmit packets.

Abstract: A method of signal generation includes selecting a subset of contiguous OFDM symbols from a set of contiguous OFDM symbols, selecting a subset of contiguous subcarriers from a set of subcarriers, and generating a preamble that occupies the subset of contiguous subcarriers in the subset of contiguous OFDM symbols. The preamble includes portions in respective OFDM symbols of the subset of contiguous OFDM symbols. In the time domain each preamble portion corresponds to a repeating sequence of samples when subcarriers outside of the subset of contiguous subcarriers are filtered out. Generating the preamble may include flipping the sign of one or more occurrences of the repeating sequence for a final preamble portion and may include placing modulation symbols on regularly spaced subcarriers in the subset of contiguous subcarriers and phase-shifting the modulation symbols for a respective preamble portion with respect to a previous preamble portion.

Abstract: A communication device includes a resource allocation module to allocate coax resources for signals to be transmitted over a cable plant and a coax physical layer device to transmit the signals over the cable plant using the allocated coax resources. The communication device also includes a media access controller, coupled to the multi-point control protocol implementation and the coax physical layer device, to provide to the coax physical layer device a bitstream that includes data for the signals and also includes information specifying the allocated coax resources.

Abstract: A physical-layer device includes a first sublayer to receive a first continuous bitstream from a media-independent interface and to provide a second continuous bitstream to the media-independent interface. The physical-layer device also includes a second sublayer to transmit first signals corresponding to the first continuous bitstream and to receive second signals corresponding to the second continuous bitstream. The second sublayer is to transmit the first signals and receive the second signals using time-division duplexing in a first mode of operation and using frequency-division duplexing in a second mode of operation.

Abstract: A physical-layer device includes a first sublayer to receive a first continuous bitstream from a media-independent interface and to provide a second continuous bitstream to the media-independent interface. The physical-layer device also includes a second sublayer to transmit first signals corresponding to the first continuous bitstream onto an external link during a first plurality of time windows and to receive second signals corresponding to the second continuous bitstream from the external link during a second plurality of time windows. The second plurality of time windows is distinct from the first plurality of time windows.

Abstract: An optical-coax unit (OCU) includes an optical PHY to receive and transmit optical signals and a coax PHY to receive and transmit coax signals. The OCU also includes a media-independent interface to provide a first continuous bitstream from the optical PHY to the coax PHY and a second continuous bitstream from the coax PHY to the optical PHY. The first continuous bitstream corresponds to received optical signals and transmitted coax signals, and the second continuous bitstream corresponds to received coax signals and transmitted optical signals.

Abstract: Successive pairs of OFDM symbols are transmitted by an OFDM transmitter and received by an OFDM receiver. The successive pairs include a first pair of OFDM symbols. First and second OFDM symbols of the first pair both include pilot symbols on two subcarriers that are symmetric about a center carrier frequency. The two subcarriers are the same for the first and second OFDM symbols. The pilot symbols on the two subcarriers for the first and second OFDM symbols compose an orthogonal matrix. The OFDM receiver estimates frequency responses at frequencies including the frequencies of the two subcarriers and compensates for signal impairment based at least in part on the estimated frequency responses.

Abstract: A receiver receives a repeating or periodic signal and, based on the signal, estimates a carrier frequency offset for the receiver. Based on the signal and the estimated carrier offset, an I/O mismatch for the receiver is estimated and compensation for the estimated I/O mismatch is performed. After compensating for the estimated receiver I/O mismatch, the carrier frequency offset is re-estimated.

Abstract: A media converter is to be coupled to an optical line terminal via an optical link and to a plurality of coax network units via coax links in a cable plant. The media converter includes an optical physical-layer device to receive and transmit optical signals via the optical link and a coax physical-layer device to receive and transmit electrical signals via the coax links. The media converter also includes an implementation of an optical-coax convergence layer to schedule transmissions of electrical signals from the plurality of coax network units by allocating coax resources among the plurality of coax network units in accordance with resource allocation for the optical link.

Abstract: A method of registering a coax network unit (CNU) in a network is performed at an optical-coax unit (OCU). In the method, a first discovery message is broadcasted to a plurality of CNUs. In response, a first registration request is received from a first CNU of the plurality of CNUs. In response to the first registration request, a proxy entity corresponding to the first CNU is implemented in the OCU. A second discovery message is received from an optical line terminal (OLT). In response to the second discovery message, a second registration request is transmitted to the OLT requesting registration of the proxy entity with the OLT.

Abstract: A media converter is coupled to an optical link terminal and a plurality of coax network units in a cable plant. The media converter receives packets from the optical link terminal via an optical link. The packets include first packets addressed to coax network units on the cable plant and second packets addressed to network units outside of the cable plant. The media converter forwards the first packets to the coax network units on the cable plant via one or more coax links, such that the first packets are forwarded to each coax network unit on the cable plant, and discards the second packets.

Abstract: An apparatus and method for cooperative transmission in a multi-antenna relay wireless communication system are provided. A receiving end includes an estimator, a reader, a feedback unit and a detector. According to the present invention, the receiving end receives the signal from both the transmitting end and the relay station. Therefore, a reception gain is obtained and a high throughput can be ensured.

Abstract: An apparatus and method for cooperative transmission in a multi-antenna relay wireless communication system are provided. A receiving end includes an estimator, a reader, a feedback unit and a detector. According to the present invention, the receiving end receives the signal from both the transmitting end and the relay station. Therefore, a reception gain is obtained and a high throughput can be ensured.