Patent application number | Description | Published |
20090060078 | NEAR SOFT-OUTPUT MAXIMUM-LIKELIHOOD DETECTION FOR MULTIPLE-INPUT MULTIPLE-OUTPUT SYSTEMS - Systems and methodologies are described that provide low-complexity soft-output detection for MIMO communication systems. Looping can be performed over a set of constellation points per spatial stream to obtain distance metrics for each of a series of transmitted streams, for which values for the other transmitted streams can be estimated using a MIMO channel matrix and a sub-optimal MIMO algorithm. Examples of MIMO algorithms that can be utilized include Per-Stream List Detection (PSLD), Lattice-Reduced Detection (LRD), and a Guided-M Algorithm. Performance can be further improved by pre-processing the MIMO channel matrix and/or by utilizing techniques for Enhanced Metric Usage (EMU). | 03-05-2009 |
20090190697 | DECODING TECHNIQUES FOR MULTI-ANTENNA SYSTEMS - In one embodiment, a wireless device for a wireless data communication system including the wireless device and a base station. The base station includes a plurality of first groups and a signal-processing unit. Each first group includes a receiver and at least one antenna connected to the receiver. The signal-processing unit includes memory and a processor adapted to process signals received by the first groups using a Maximum Likelihood Detection (MLD) method. The wireless device includes a plurality of second groups, each second group adapted to transmit a wireless signal to at least one first group via a corresponding communication channel. Each second group further includes a transmitter and at least one antenna connected to the transmitter. The signal-processing unit is adapted to store, in the memory, information corresponding to one or more transfer functions, each transfer function corresponding to transmission of a wireless signal from an antenna of the second groups to an antenna of the first groups. The transmitters and receivers are adapted to operate at essentially the same frequency or frequency band. Two or more of the communication channels are generated simultaneously. Each transmitter is adapted to modulate an information signal on a radio-frequency signal according to a Quadrature Amplitude Modulation (QAM) method to transmit QAM symbols. Each receiver is adapted to demodulate information signals from a received radio-frequency signal according to the QAM method. | 07-30-2009 |
20090252100 | METHODS AND APPARATUS FOR REVERSE LINK ACKNOWLEDGEMENT IN A WIRELESS LOCAL AREA NETWORK (WLAN) - Methods and apparatus for reverse link acknowledgement in a wireless local area network. A method includes receiving, at a first node, a data communication over a common channel, the data communication being decodable by other nodes. The method also includes determining transmission resources from the data communication, wherein the transmission resources are different for each node, and transmitting a response over the common channel using the determined transmission resources. An apparatus includes a transmitter configured to transmit to a plurality of nodes a data communication over the common channel, and a receiver configured to receive responses from the plurality of nodes, wherein each response was sent using different transmission resources determined from the data communication. | 10-08-2009 |
20100008318 | SYSTEMS AND METHODS FOR PROVIDING A SEPARATE CONTENTION WINDOW ALLOWING ALLOCATIONS FOR PENDING UPLINK SDMA TRANSMISSION OPPORTUNITIES - A method for providing uplink spatial division multiple access (SDMA) transmission opportunities (TXOP) is described. A demarcation indication may be sent to one or more subscriber stations. An SDMA contention window may be started. An allocation indication may be received. Requested uplink SDMA TXOP resources may be allocated according to the allocation indication. | 01-14-2010 |
20100046656 | PREAMBLE EXTENSIONS - Systems and/or methods for communication that generate a plurality of spatial streams are disclosed. Each of the spatial streams comprises a plurality of symbols. At least a portion of a training sequence is distributed across a first symbol in a first one of the spatial streams and a second symbol in a second one of the spatial streams. | 02-25-2010 |
20100061262 | JOINT PACKET DETECTION IN A WIRELESS COMMUNICATION SYSTEM - A packet detector joint detects 802.11a packets, 802.11b packets and interference that is within a monitored frequency range but is not formatted as 802.11a packets or 802.11b packets. The packet detector can use signals from one or more antennas. Detection of signals is done using differentially detected correlations. In addition to packet detection, the packet detector can identify signal levels, noise levels and locations of narrowband interference. The process of packet detection and identifying other indicators can be done simultaneously and as the signal is being received. | 03-11-2010 |
20100111234 | SYSTEM FOR SOFT SYMBOL DECODING MIMO LOG-MAP DETECTION - A soft symbol decoder for use in a multiple input multiple output (MIMO) and OFDM (orthogonal frequency division multiplexing) system. The decoder generates soft symbol values for a digital signal that represents a number of source bits. The source bits are transmitted as symbols in corresponding to points in a signaling constellation. Soft metrics are determined by searching for all possible multi-dimensional symbols that could have been transmitted. The method includes transmitting a sample of the multi-dimensional symbol using K transmit antennas. The multi-dimensional symbol is represent-able as a complex, K-dimensional vector x. Each vector component of vector x represents a signal transmitted with one of the K transmit antennas. After transmission through a communication channel, a sample corresponding to the transmitted sample is received. The received sample is represented by a complex, N-dimensional vector y, where N is the number of receive antennas in the MIMO system. After the sample is received, a soft metric L(b | 05-06-2010 |
20100290449 | PREAMBLE EXTENSIONS - Systems and/or methods for communication that generate a plurality of spatial streams are disclosed. Each of the spatial streams comprises a plurality of symbols. At least a portion of a training sequence is distributed across a first symbol in a first one of the spatial streams and a second symbol in a second one of the spatial streams. | 11-18-2010 |
20110110454 | MIXED MODE PREAMBLE DESIGN FOR SIGNALING NUMBER OF STREAMS PER CLIENT - Certain aspects of the present disclosure present a technique for designing a signal (SIG) field of a mixed mode preamble transmitted to a plurality of user terminals. The SIG field can signal a number of spatial streams assigned to each user. The SIG field is designed such that a robust interference cancellation can be achieved at each user terminal. | 05-12-2011 |
20110205913 | BEAMFORMING AND SDMA METHODS FOR WIRELESS LAN AND OTHER APPLICATIONS - Embodiments of the present disclosure present methods for calculating beamforming and spatial division multiple access (SDMA) weights utilizing minimum mean square error (MMSE) method. The beamforming and SDMA weights may also be normalized for further performance improvements. | 08-25-2011 |
20120002744 | Methods and Systems for Transmitting an Information Signal in a Multiple Antenna Communication System - Methods and systems are provided for transmitting a plurality of information signals in a multiple antenna communication system. One or more information signals are coded using a plurality of coders to generate the plurality of coded information signals and an Inverse Fast Fourier Transformation is performed on each of the plurality of coded information signals to create a corresponding output signal. Each of the corresponding output signals are transmitted on a different antenna. Each of the plurality of coded information signals can optionally be separated into K signals, On the receiver side, a signal comprising K different frequencies is received on at least N receive antennas and a Fast Fourier Transformation is applied to each of the at least N received versions of the signal comprising K different frequencies to generate N*K low frequency signals. The N*K separate low frequency signals are then combined to recover a transmitted information signal, based on one or more transfer functions from each of a plurality of transmit antennas to each of the N receive antennas. | 01-05-2012 |
20120327868 | LOW-LATENCY INTERLEAVING FOR LOW-DENSITY PARITY-CHECK (LDPC) CODING - Certain aspects of the present disclosure relate to systems, devices, and methods for communicating over a plurality of tones and spatial streams. Modulation symbols may be mapped to tones and spatial streams so as to increase frequency and/or spatial diversity without substantially increasing latency. For certain aspects, this interleaving approach may be performed on low-density parity-check (LDPC) codewords. | 12-27-2012 |
20140029685 | PREAMBLE EXTENSIONS - Systems and/or methods for communication that generate a plurality of spatial streams are disclosed. Each of the spatial streams comprises a plurality of symbols. At least a portion of a training sequence is distributed across a first symbol in a first one of the spatial streams and a second symbol in a second one of the spatial streams. | 01-30-2014 |
20140079048 | PREAMBLE EXTENSIONS - Systems and/or methods for communication generate a plurality of spatial streams. Each of the spatial streams comprises a plurality of symbols. At least a portion of a training sequence is distributed across a first symbol in a first one of the spatial streams and a second symbol in a second one of the spatial streams. | 03-20-2014 |
20140301498 | Non-linear Interference Cancellation Across Aggressor Transmitters and Victim Receivers - Systems and methods are disclosed to implement non-linear interference cancellation (NLIC) across chips or dies in communication systems to cancel or mitigate self-jamming interference. A victim transceiver may receive an analog baseband transmit (Tx) signal from an aggressor transceiver. The analog baseband Tx signal may be tapped from a digital analog converter (DAC) of the aggressor transceiver. Alternatively, the analog baseband Tx signal may be generated by the aggressor transceiver using an auxiliary down-conversion and filtering stage. The victim transceiver may receive a composite baseband Rx signal from the victim transceiver front-end. The composite baseband Rx signal includes the desired Rx signal and an interference signal. The victim transceiver may sample the analog baseband Tx signal to generate a digital signal replica of the analog baseband Tx signal for the NLIC operation to cancel or mitigate the interference signal present in the composite baseband Rx signal. | 10-09-2014 |