Patent application number | Description | Published |
20090238303 | METHOD AND SYSTEM FOR CODEBOOK-BASED CLOSED-LOOP MIMO USING COMMON PILOTS AND ANALOG FEEDBACK - A method and system that enables the usage of sounding-based feedback or analog feedback in a MIMO communication system with non-beamformed or broadcast pilot symbols is disclosed. The mobile station may employ a feedback channel to send a sounding waveform to a base station, a feedforward channel to receive from the base station codebook weights derived from the send sounding waveform, a receiver to receive communication from the base station, and a processor to detect beamformed data from the received communication and received codebook weights from the base station. The base station processes the sounding waveform to determine codebook weights on groups of subcarriers. Additionally, the base station transmits the beamformed payload and broadcast pilots to the mobile station. | 09-24-2009 |
20090274226 | SOUNDING CHANNEL BASED FEEDBACK IN A WIRELESS COMMUNICATION SYSTEM - An apparatus and method for providing sounding channel based feedback in an OFDM communication system includes a first step ( | 11-05-2009 |
20090323614 | FRAME ALLOCATION TO SUPPORT LEGACY WIRELESS COMMUNICATION PROTOCOLS ON UPLINK TRANSMISSION | 12-31-2009 |
20100142462 | PASSIVE COORDINATION IN A CLOSED LOOP MULTIPLE INPUT MULTIPLE OUT PUT WIRELESS COMMUNICATION SYSTEM - A system and method for passive coordination of base stations in a closed-loop multiple-input multiple-output wireless communication system, includes a first step | 06-10-2010 |
20100150266 | METHOD AND APPARATUS FOR CODEBOOK-BASED FEEDBACK IN A CLOSED LOOP WIRELESS COMMUNICATION SYSTEM - A method and apparatus are provided for feedback for closed-loop transmitting with multiple transmit antenna elements and multiple receive antenna elements. A base station includes a codebook containing sets of weightings for the multiple transmit antenna elements, with each set of weightings identified by an index and the codebook known to the base station and a served mobile station (MS). The base station pre-codes pilot signals using a precoding matrix, preferably a unitary matrix, to produce pre-coded pilot signals, which precoding matrix may or may not be known to the MS and which precoding matrix may or may not be included in the codebook. The base station then transmits the pre-coded pilot signals to the MS via the multiple transmit antenna elements and, in response, receives an index to a set of weightings in the codebook for use in a subsequent transmission of a data stream. | 06-17-2010 |
20100260234 | CLOSED-LOOP TRANSMISSION FEEDBACK IN WIRELESS COMMUNICATION SYSTEMS - Channel information feedback takes place by calculating channel information to feed back to the base station. The channel quality information is spread by a remote unit with spreading codes from mutually unbiased bases and transmitted to the base station. The advantages of spreading the feedback channel are that multiple mobiles can send their feedback on the same time-frequency resources making the feedback very efficient and also improving feedback performance through orthogonal spreading which gives a spreading gain above noise and interference. Using the spreading codes from mutually unbiased bases can reduce interference across sectors. | 10-14-2010 |
20100284482 | METHOD AND APPARATUS FOR RADIO RESOURCE ALLOCATION IN AN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING COMMUNICATION SYSTEM - In an OFDM communication system, wherein a frequency bandwidth is divided into multiple Physical Resource Units (PRUs), a Frequency Partitioning Configuration Module (FPCM) is provided that configures a physical layer for use in multiple coverage areas. The FPCM divides the PRUs into a first group, for frequency selective allocations, and a second group, for frequency diverse allocations. The FPCM subdivides each of the two groups into multiple sets of PRUs, maps the sets of PRUs from the first group to consecutive PRUs allocated for contiguous segment allocation (CS-PRUs), and maps the sets of PRUs from the second group to consecutive PRUs allocated for distributed segment allocation (DS-PRUs). The FPCM permutes the DS-PRUs and allocates the CS-PRUs and the permuted DS-PRUs to at least one frequency partition. | 11-11-2010 |
20110105051 | DIFFERENTIAL CLOSED-LOOP TRANSMISSION FEEDBACK IN WIRELESS COMMUNICATION SYSTEMS - A method and apparatus for providing channel feedback is provided herein. During operation a covariance matrix at time t (R) is calculated as a function of a received downlink signal. Matrix C | 05-05-2011 |
20110164691 | CLOSED-LOOP TRANSMISSION FEEDBACK IN WIRELESS COMMUNICATION SYSTEMS - A method and apparatus for providing channel feedback is provided herein. During operation a covariance matrix at time t (R) is calculated by the mobile as a function of a received downlink signal. In order to reduce overhead, R is normalized and quantized by the mobile using multiple codebook entries plus at least one constant for quantization. The mobile then transmits the normalized and quantized covariance matrix back to the base station as bit values indicating the selected entries from the codebook plus bit values corresponding to the at least one constant. The base unit then uses the covariance matrix estimate to determine appropriate channel beamforming weights, and instructs transmit beamforming circuitry to use the appropriate weights. | 07-07-2011 |
20110176439 | CLOSED-LOOP FEEDBACK IN WIRELESS COMMUNICATIONS SYSTEM - A method and apparatus for providing channel feedback is provided herein. During operation a covariance matrix at time t (R) is calculated as a function of a received downlink signal. In order to reduce overhead, R is normalized and quantized. The base unit then uses the covariance matrix estimate to determine appropriate channel beamforming weights, and instructs transmit beamforming circuitry to use the appropriate weights. In an embodiment, circuitry performs a method of calculating a first precoding matrix index I from a codebook using a received signal, calculating a second codebook index J* using the first precoding matrix index I to approximate a covariance matrix and calculating a quantized coefficient α* to approximate the covariance matrix wherein the quantized coefficient α* is determined using the first precoding matrix index I. | 07-21-2011 |
20110176581 | METHOD AND APPARATUS FOR PILOT SIGNAL PROCESSING IN A WIRELESS COMMUNICATION SYSTEM - A wireless communication system is provided that spreads pilot signals, or channel state information reference signals (CSI-RSs), using a spreading code chosen from a set of mutually unbiased bases (MUBs). The advantages of such spreading with MUBs are that multiple base stations can send their pilot signals on a same time-frequency resources, making the pilot signal design very efficient and also improving channel estimation at a user equipment through orthogonal and quasi-orthogonal spreading which gives a gain above noise and interference. A short spreading code chosen from MUBs may be used for spreading pilot signals transmitted from each antenna of a base station within a time-frequency resource comprising multiple closely-spaced subcarriers in frequency and/or multiple closely-spaced symbols in time. | 07-21-2011 |
20110243262 | METHOD AND APPARATUS FOR CHANNEL SOUNDING IN AN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING COMMUNICATION SYSTEM - An Orthogonal Frequency Division Multiplexing communication system is provided that triggers a transmission of an uplink sounding signal by use of a Downlink Control Information (DCI) message. In various embodiments of the invention, the DCI message may be used to individually trigger an uplink sounding signal by a single user equipment or may be used to trigger an uplink sounding signal by a group of users equipment. | 10-06-2011 |
20120147813 | CLOSED-LOOP FEEDBACK DURING INITIAL RANGING PROCEDURE - During operation, the choice of the initial ranging code (sometimes referred to as a ranging preamble code, or a random-access preamble) at the mobile station is associated with a PMI feedback to be signaled to the base station during the initial ranging. More particularly, during initial system access a ranging code is transmitted by the mobile station to the base station. The mobile station chooses one of the available ranging codes based on the channel conditions and associates the ranging code with channel feedback information. The ranging code is then transmitted to the base station, and provides the base station with the channel feedback information. | 06-14-2012 |
20130121432 | METHOD AND APPARATUS FOR CODEBOOK BASED FEEDBACK IN A CLOSED LOOP WIRELESS COMMUNICATION SYSTEM - A method and apparatus are provided for feedback for closed-loop transmitting with multiple transmit antenna elements and multiple receive antenna elements. A base station includes a codebook containing sets of weightings for the multiple transmit antenna elements, with each set of weightings identified by an index and the codebook known to the base station and a served mobile station (MS). The base station pre-codes pilot signals using a precoding matrix, preferably a unitary matrix, to produce pre-coded pilot signals, which precoding matrix may or may not be known to the MS and which precoding matrix may or may not be included in the codebook. The base station then transmits the pre-coded pilot signals to the MS via the multiple transmit antenna elements and, in response, receives an index to a set of weightings in the codebook for use in a subsequent transmission of a data stream. | 05-16-2013 |
20130279615 | DIFFERENTIAL CLOSED-LOOP TRANSMISSION FEEDBACK IN WIRELESS COMMUNICATION SYSTEMS - A method and apparatus for providing channel feedback is provided herein. During operation a covariance matrix at time t (R) is calculated as a function of a received downlink signal. Matrix C | 10-24-2013 |