14024results about "Modulated-carrier systems" patented technology

A method of determining a channel estimate of a first transmission channel in a communications system. The method comprises deriving a first set of channel estimates from symbols received through said first transmission channel; deriving a second set of channel estimates from symbols received through a second transmission channel in the communications system; determining a scale factor between the first and second sets of channel estimates from a least squares error criterion; and determining the channel estimate of the first transmission channel as a channel estimate of the second transmission channel scaled by the determined scale factor.

A method for transmitting channel status information (CSI) of downlink multi-carrier transmission includes generating the CSI including at least one of a rank indicator (RI), a first precoding matrix index (PMI), a second PMI and a channel quality indicator (CQI) for one or more downlink carriers, the CQI being calculated based on precoding information determined by a combination of the first and second PMIs, determining, when two or more CSIs collide with one another in one uplink subframe of one uplink carrier, a CSI to be transmitted on the basis of priority, and transmitting the determined CSI over a uplink channel. If a CSI including an RI or a wideband first PMI collides with a CSI including a wideband CQI or a subband CQI, the CSI including a wideband CQI or a subband CQI has low priority and is dropped.

A unified, unidirectional serial link is described for providing data across wired media, such as a chip-to chip or a card-to-card interconnect. It consists of a transmit section and a receive section that are operated as pairs to allow the serial data communication. The serial link is implemented as part of a VLSI ASIC module and derives its power, data and clocking requirements from the host modules. The logic transmitter portion contains a phase locked loop (PLL), a dibit data register, a finite impulse response (FIR) filter and a transmit data register. The phase locked loop comprises both a digital coarse loop and an analog fine loop. The digital receiver portion contains a PLL, an FIR phase rotator, a phase rotator control state machine, and a clock buffer. The transmitter and the receiver each preferably utilize a pseudo-random bit stream (PRBS) generator and checker.

A device and method for providing power line communications via an underground residential distribution power system is provided. One embodiment of the present invention includes a medium voltage interface device that may include a first port configured to communicate over the power line and a network interface. A first amplifier may form part of a first communication path between the first port and the network interface and be configured to amplify data signals transmitted via the first port. In addition, a second amplifier may form part of a second communication path between the first port and the network interface and be configured to amplify data signals received via the first port. In addition, the embodiment may include a diplexer forming part of the first communication path between the first amplifier and the first port and forming part of the second communication path between the second amplifier and the first port. The device may include an electro-optic converter coupled to the network interface to convert between electrical and optic data signals, wherein the network interface is configured to communicate via one or more fiber optic conductors.

An apparatus is provided for high frequency multiplexed electrical line communication for cable TV, telephone, internet, security and other control applications over the mid and low voltage power lines and directly through the transformers. The apparatus includes a transmitter, a receiver, a modem, a multiplexer and multiple couplers at each of two or more locations along an electrical line. The couplers have capacitive circuits serially connected with an air-core or dielectric-core transformer. The capacitive circuits resonate with the transformer at a preselected frequency. The coupler eliminates noise and is matched to the characteristic impedance of the line at the preselected frequency, which linearizes communication on the line and allows high speed data and voice communication over long distances. Multiple modulators and demodulators are used to produce multiple modulated carrier frequencies.

The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-1 and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.

Coding techniques for a (e.g., OFDM) communication system capable of transmitting data on a number of “transmission channels” at different information bit rates based on the channels' achieved SNR. A base code is used in combination with common or variable puncturing to achieve different coding rates required by the transmission channels. The data (i.e., information bits) for a data transmission is encoded with the base code, and the coded bits for each channel (or group of channels with the similar transmission capabilities) are punctured to achieve the required coding rate. The coded bits may be interleaved (e.g., to combat fading and remove correlation between coded bits in each modulation symbol) prior to puncturing. The unpunctured coded bits are grouped into non-binary symbols and mapped to modulation symbols (e.g., using Gray mapping). The modulation symbol may be “pre-conditioned” and prior to transmission.

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.

In a hybrid communication system a wireless communication link is maintained between a power line communication medium and a non-power line communication medium. Wireless communication is established within an unlicensed frequency band and monitored for quality. If the quality falls below a threshold, a wireless communication link is established within a licensed frequency band. The wireless link may be maintained between a power line communication system (PLCS) backhaul point and an internet protocol (IP) network access point, and / or between a PLCS endpoint communication interface and a premises communication device.

A PFC circuit modulating a power line using pulse width modulation (PWM) to drive a power MOSFET and series inductor across the power line. Since many modern electronic systems include a power factor correction circuit (PFC) that already includes a series inductor and power MOSFET, a PLC is incorporated into a controller to inject a PLC transmit signal into a control loop for the PFC circuit. This can be done using either an analog PFC controller, such as the UCC28517, the UCC2819A, or a digital PFC controller such as based on a TMS320C24xx DSP.

A system and method are described that use impulse radio technology to enhance the capabilities of a robot. In one embodiment, a system, a robot and a method are provided that use the communication capabilities of impulse radio technology to help a control station better control the actions of the robot. In another embodiment, a system, a robot and a method are provided that use the communication, position and / or radar capabilities of impulse radio technology to help a control station better control the actions of a robot in order to, for example, monitor and control the environment within a building.

The communication system includes a hybride fiber / coax distribution network. A head end provides for downstream transmission of telephony and control data in a first frequency bandwidth over the hybrid fiber / coax distribution network and reception of upstream telephony and control data in a second frequency bandwidth over the hybrid fiber / coax distribution network. The head end includes head end multicarrier modem for modulating at least downstream telephony information on a plurality of orthogonal carriers in the first frequency bandwidth and demodulating at least upstream telephony information modulated on a plurality of orthogonal carriers in the second frequency bandwidth. The head end further includes a controller operatively connected to the head end multicarrier modem for controlling transmission of the downstream telephony information and downstream control data and for controlling receipt of the upstream control data and upstream telephony information. The system further includes service units, each service unit operatively connected to the hybrid fiber / coax distribution network for upstream transmission of telephony and control data in the second frequency bandwidth and for receipt of the downstream control data and telephony in the first frequency bandwidth. Each service unit includes a service unit multicarrier modem for modulating at least the upstream telephony information on at least one carrier orthogonal at the head end terminal to another carrier in the second frequency bandwidth and for demodulating at least downstream telephony information modulated on at least a band of a plurality of orthogonal carriers in the first frequency bandwidth. Each service unit also includes a controller operatively connected to the service unit multicarrier modem for controlling the modulation of and demodulation performed by the service unit multicarrier modem. A method of monitoring communication channels, a distributed loop method for adjusting transmission characteristics to allow for transmission of data in a multi-point to point communication system, a polyphase filter technique for providing ingress protection and a scanning method for identifying frequency bands to be used for transmission by service units are also included. Also provided is a method and apparatus for performing a Fast Fourier Transform (FFT). In one embodiment, a scalable FFT system is built using a novel dual-radix butterfly core.

The invention computes frequency-domain channel gains by compiling a set of estimated channel gains as a function of pilot sequences, a set of analytical channel gains variables, and a set of weighting coefficients variables. A plurality of weighting coefficients are computed as a function of time and frequency correlation functions, a noise correlation matrix, and pilot sequences. A weighting matrix is computed from the weighting coefficients. After receiving a training sequence from at least one transmitter, a received data matrix is computed from the training sequence. The weighting matrix and the received data matrix are used to compute the frequency-domain channel gains. The invention also provides a method for reducing the computational complexity of estimating the time and frequency response of at least one desired signal received by at least one antenna. Also, the time and frequency response of at least one desired signal received by at least one antenna can be both interpolated and predicted with the present invention.