Abstract: In an orthogonal frequency division multiplexed (OFDM) system, a transmitter and/or receiver communicate separate data streams on non-orthogonal spatial channels. Each spatial channel may use the same set of OFDM subcarriers and may take advantage of the multipath characteristics of the spatial channel allowing the communication of additional data without an increase in frequency bandwidth. Space-frequency subcarrier modulation assignments may be dynamically assigned on a per subcarrier basis as well as a per spatial channel basis to help maximize the data-carrying capacity of the channel. In some embodiments, each of the spatial channels may be associated with one of a plurality of spatially diverse antennas. In other embodiments, beamforming may be performed to allow the transmission and/or reception of signals within the spatial channels.

Abstract: Various embodiments are described for a trained data transmission for communication systems.

Abstract: An adaptation technique is selected for use in a wireless network based on estimated throughput. In at least one embodiment, throughput is estimated for a wireless channel for both prefix adaptation and postfix adaptation. An adaptation technique is then selected based on the estimates. In some embodiments, an adaptation validity duration is determined to gauge the potential effectiveness of adaptation information associated with a wireless channel.

Abstract: Apparatus and methods for selecting a transmit power level and subcarrier modulation assignments based on measured channel conditions to achieve a performance level for communications over a symbol-modulated subcarrier communication channel are provided. In some embodiments, the transmit power level may be changed depending on whether a desired packet error rate and/or a desired link data rate can be achieved based on selected subcarrier modulation assignments and a selected transmit power level.

Abstract: Embodiments of the present invention provide methods and apparatus for wireless communication using codeword with high-rate codes. Other embodiments may be described and claimed.

Abstract: Apparatus and methods for selecting a transmit power level and subcarrier modulation assignments based on measured channel conditions to achieve a performance level for communications over a symbol-modulated subcarrier communication channel are provided. In some embodiments, the transmit power level may be changed depending on whether a desired packet error rate and/or a desired link data rate can be achieved based on selected subcarrier modulation assignments and a selected transmit power level.

Abstract: A multicarrier communication device can vary the number of subcarriers being used to carry on multicarrier communication within a network, based on a predetermined criterion (e.g., traffic load, etc.).

Abstract: Briefly, in accordance with one embodiment of the invention, a wireless network may include transmitters that may transmit information over a channel. the transmitter may also transmit channel side information over the channel. Further, the transmitters may adjust when channel side information is transmitted in accordance with the channel coherence time.

Abstract: Systems, devices and methods for updating link adaptations in multi-carrier modulated signals between an access point (AP) and a wireless local area network (WLAN) station (STA) include (are configured for) periodically transmitting a channel sounding signal from the AP. The STA receives each unsolicited channel sounding signal and evaluates the current channel conditions between the AP and STA. The AP adjusts a rate of transmission of the channel sounding signals in accordance with the channel coherence time so that the channel estimates performed by the STA will be valid within the time varying characteristics of the channel. Depending on the length of the coherence time for network environment, the channel sounding signals may be AP beacons, low overhead signal fragments with no payload, or a combination of both.

Abstract: A computationally efficient channel estimation technique for use within an orthogonal frequency division multiplexing (OFDM) communication system determines coefficients of a channel transfer function by calculating the dot products of a pilot vector and a plurality of interpolation vectors. One dot product is preferably calculated for each subcarrier of interest within the system. The pilot vector is extracted from an OFDM symbol received from a communication channel. In a preferred approach, a number of interpolation vectors are precalculated and stored within a communication device for subsequent use during channel estimation and equalization operations. The technique is highly flexible and can be implemented using, for example, a variable user block size or a variable pilot vector size.

Abstract: A method and apparatus for encoding/decoding information using low density parity check (LDPC) codewords of varying lengths. In one implementation, an encoder/decoder uses a parity check matrix having a size that corresponds to a length of information for each codeword. In one example, the size of the parity check matrix may be retrieved from multiple stored matrices having different sizes. In other examples, a mother code matrix may be dynamically adjusted by puncturing parity bits and/or deleting information bits. Other inventive embodiments and adaptations are also disclosed.

Abstract: A method, apparatus and system relate to detecting an interfering device in a wireless network such as a wireless local area network (WLAN). In wireless networks using orthogonal frequency division multiplexing (OFDM) and adaptive bit loading (ABL), adaptive modulation information should be somewhat symmetric in uplink and downlink directions. By comparing modulation adaptations in the uplink and downlink directions of a communication channel between at least two terminals, identified differences can indicate the presence of a potential interferer in the wireless network. A location of the potential interferer can be estimated if a location of one or more network terminals experiencing interference is known or can be determined. An exemplary implementation for a device of the invention may be as an Access Point (AP) in the WLAN.

Abstract: A system, apparatus, and method includes a decoder to decode information including a low density parity check (LDPC) codeword received at a node using entries defined in a parity check base matrix. Other embodiments are described and claimed. The system further includes an antenna.

Abstract: A system, apparatus, and method includes an encoder to encode information comprising a codeword to be transmitted at a node using variable length block codes applied to a packet having a variable length data payload. Other embodiments are described and claimed. The system further includes an antenna and a transceiver coupled to the encoder.

Abstract: A wireless transmitter system for use in maintaining a wireless link with a remote transceiver includes a beamforming transmit antenna structure and a power control unit for controlling transmit power levels. The system determines the direction of the remote transceiver and then generates a transmit antenna beam in that direction. The power control unit then determines the antenna gain of the generated beam and uses the antenna gain information to adjust the transmit power level of the system so that it does not exceed government mandated limits. In one embodiment, the average transmit duty cycle of the system is also used to adjust transmit power. The system is capable of achieving a maximum transmit power without exceeding applicable power limits.

Abstract: A computationally efficient channel estimation technique for use within an orthogonal frequency division multiplexing (OFDM) communication system determines coefficients of a channel transfer function by calculating the dot products of a pilot vector and a plurality of interpolation vectors. One dot product is preferably calculated for each subcarrier of interest within the system. The pilot vector is extracted from an OFDM symbol received from a communication channel. In a preferred approach, a number of interpolation vectors are precalculated and stored within a communication device for subsequent use during channel estimation and equalization operations. The technique is highly flexible and can be implemented using, for example, a variable user block size or a variable pilot vector size.

Abstract: An apparatus may include an orthogonal frequency division multiplexing (OFDM) physical layer interface. An adaptive subcarrier demodulator or an adaptive subcarrier modulator may be coupled to the OFDM physical layer interface to implement adaptive bit loading (ABL). A decoder or an encoder may be coupled to the adaptive subcarrier demodulator or to the adaptive subcarrier modulator to implement low density parity checking.

Abstract: A method and apparatus to select a channel of operation for a wireless network device may examine channels supported by the device to gather information regarding present use of the channels. A best channel may be determined for the wireless network device by identifying a channel that maximizes a predetermined performance metric.

Abstract: A blade includes a plurality of first fibers, wherein each of the plurality of first fibers is angled between about 5° and about 35° with respect to a pitch axis of said blade, and a plurality of second fibers, wherein each of the plurality of second fibers is angled between about 95° and about 125° with respect to the pitch axis of said blade.

Abstract: A technique includes receiving a signal that indicates a modulated symbol during a given time slice of the signal. Sliding window frequency transformations of the signal are performed, and each sliding window transformation is associated with a different time interval of the signal. One of the time intervals is selected to correspond to the time slice. The result of the frequency transformation associated with the selected time interval is used to obtain an indication of the demodulated symbol.