Patent application number | Description | Published |
20090023467 | METHOD AND APPARATUS FOR PERFORMING SPACE DIVISION MULTIPLE ACCESS IN A WIRELESS COMMUNICATION NETWORK - A method and apparatus for performing space division multiple access in wireless communications are disclosed. After the receipt of a set of training data from a base station, an estimated channel state information (CSI) is then generated by a mobile station. The CSI is subsequently quantized. The mobile station then determines whether or not the quantized CSI falls within a set of thresholds. If the quantized CSI falls within the set of thresholds, the mobile then sends feedback information to the base station to allow the base station to consider the mobile station as one of the mobile station candidates available for data communications. Otherwise, if the quantized CSI falls outside the set of thresholds, the mobile station then discards the quantized CSI. | 01-22-2009 |
20090067402 | System and Method For Distributed Input-Distributed Output Wireless Communications - A system and method are described for dynamically adapting the communication characteristics of a multiple antenna system (MAS) with multi-user (MU) transmissions (“MU-MAS”). For example, a method according to one embodiment of the invention comprises: transmitting a training signal from each antenna of a base station to each of a plurality of wireless client devices, each of the client devices analyzing each training signal to generate channel characterization data, and receiving the channel characterization data at the base station; computing a plurality of MU-MAS precoder weights based on the channel characterization data, the combined MU-MAS precoder weights comprising a MU-MAS channel matrix; determining instantaneous or statistical channel quality (“link quality metric”) for the wireless client devices using mutual information of MU-MAS links or singular values of the MU-MAS composite channel matrix; determining a subset of users and a MU-MAS transmission mode based on the link quality metric; precoding data using the MU-MAS precoder weights to generate precoded data signals for each antenna of the base station; and transmitting the precoded data signals through each antenna of the base station to each respective client device within the selected subset. | 03-12-2009 |
20090253380 | Apparatus and method for beamforming in a multiantenna multiuser communication system - A method for beamforming by a transmission device in a multiantenna multiuser communication system. The method includes grouping codebook indexes included in a codebook into codebook index combinations, and calculating a sum of transmission rate for each of the codebook index combinations; selecting a codebook index combination with a maximum sum of transmission rate as an optimal codebook index combination; and transmitting a codebook index corresponding to a particular reception device among codebook indexes included in the optimal codebook index combination, to the particular reception device. | 10-08-2009 |
20100172309 | SYSTEM AND METHOD FOR DISTRIBUTED INPUT DISTRIBUTED OUTPUT WIRELESS COMMUNICATIONS - A system for compensating for in-phase and quadrature (I/Q) imbalances for multiple antenna systems (MAS) with multi-user (MU) transmissions (defined with the acronym MU-MAS), such as distributed-input distributed-output (DIDO) communication systems, comprising multicarrier modulation, such as orthogonal frequency division multiplexing (OFDM). For example, one embodiment of the system comprises one or more coding modulation units to encode and modulate information bits for each of a plurality of wireless client devices to produce encoded and modulated information bits; one or more mapping units to map the encoded and modulated information bits to complex symbols; and a MU-MAS or DIDO IQ-aware precoding unit to exploit channel state information obtained through feedback from the wireless client devices to compute MU-MAS or DIDO IQ-aware precoding weights, the MU-MAS or DIDO IQ-aware precoding unit precoding the complex symbols obtained from the mapping units using the weights to pre-cancel interference due to I/Q gain and phase imbalances and/or inter-user interference. | 07-08-2010 |
20100284449 | METHODS AND COMMUNICATION SYSTEMS HAVING ADAPTIVE MODE SELECTION - Examples are generally described that include methods for selecting a transmit mode in a communications system. An example method may include calculating a first transmission rate for data in a multiple-input multiple-output mode of the communications system and calculating a second transmission rate for the data in a single-input multiple-output mode of the communications system. A mode may be selected from the group consisting of the multiple-input multiple-output mode and the single-input multiple-output mode based, at least in part, on an energy consumption of the first and second transmission rates. Data may be transmitted from a transceiver in the communications system using the selected mode. | 11-11-2010 |
20120014417 | SYSTEM AND METHOD FOR TRANSMITTING PILOT AND DATA SYMBOLS IN A RELAYED-WIRELESS COMMUNICATIONS NETWORK - Techniques are generally described for estimating a communication channel using wirelessly transmitted and retransmitted signals, each transmitted at a different power ratio. An example wireless communications system may include a base station, a relay station and a wireless device. The base station may include a transmitter configured to transmit a first signal, wherein the first signal includes pilot and data symbols with a first power ratio. The relay station may include a receiver configured to receive the first signal, and a transmitter configured to retransmit the first signal as a second signal, wherein the second signal includes pilot and data symbols with a second power ratio. The wireless device includes a receiver configured to receive the first and second signals, i.e. the transmitted and retransmitted pilot and data symbols having the first and second power ratios are received, and estimate a communications channel from the received signals. | 01-19-2012 |
20120014424 | COMMUNICATING CHANNEL STATE INFORMATION USING PREDICTIVE VECTOR QUANTIZATION - Techniques are generally described here for communicating channel state information using predictive vector quantization. In some examples, a method may include measuring channel state information based, at least in part, on signals received over a communications channel. An error vector may be calculated between the measured channel state information and predicted channel state information. The error vector may be quantized, and subsequent channel state information may be predicted based, at least in part, on the quantized error vector. | 01-19-2012 |
20120014473 | TRANSMITTING DATA OVER A COMMUNICATIONS CHANNEL - Techniques for transmitting data over a communications channel are generally described. A value of a property of an inverse of a channel matrix corresponding to the communications channel may be calculated and compared to a threshold value. If the value of the property a first one of greater than or less than the threshold value, at least one transmit message may be altered using a vector perturbation technique to generate data symbols and the data symbols may be precoded using a channel inversion technique to generate precoded data symbols. If the value of the property is the other of greater than or less than the threshold value, the at least one transmit message may be precoded using a channel inversion technique to generate precoded data symbols. | 01-19-2012 |
20120045007 | INSERTING AND DECODING REPLICATED DATA SYMBOLS IN WIRELESS COMMUNICATIONS - Examples are generally described that include transmission methods including inserting at least a portion of data from a first data stream into a second data stream to be transmitted over a communications channel. On receipt of the two data streams, examples of receiving methods include receiving the replicated data, decoding the replicated data using an estimated channel matrix, and generating an updated estimate of the channel matrix based, at least in part, on the replicated data. | 02-23-2012 |