Abstract:
PROBLEM TO BE SOLVED: To provide frequency-independent eigensteering in MISO and MIMO systems.SOLUTION: A correlation matrix is computed for a MIMO channel based on channel response matrices and decomposed to obtain NS frequency-independent steering vectors for NS spatial channels of the MIMO channel. For main path eigensteering, a data symbol stream is transmitted on the best spatial channel for the main propagation path of the MIMO channel. For receiver eigensteering, a data symbol stream is steered toward a receive antenna based on a steering vector obtained for that receive antenna. For all eigensteering schemes, a matched filter is derived for each receive antenna based on the steering vector(s) and channel response vectors for the receive antenna.
Abstract:
PROBLEM TO BE SOLVED: To provide channel estimation and spatial processing for a TDD MIMO system.SOLUTION: Calibration may be performed (512) to address differences in the responses of transmission/reception chains at an access point and a user terminal. A MIMO pilot is transmitted (522) on a first link and used (524) to derive an estimate of the first link channel response, which is decomposed to obtain a diagonal matrix of singular values. A first unitary matrix contains (526) both left eigenvectors of the first link and right eigenvectors of a second link. A steered reference is transmitted (530) on the second link using the eigenvectors in the first unitary matrix, and is processed to obtain the diagonal matrix. A second unitary matrix contains (532) both left eigenvectors of the second link and right eigenvectors of the first link. Each unitary matrix may be used to perform spatial processing (540, 542, 550, 552).
Abstract:
PROBLEM TO BE SOLVED: To provide a novel and improved method and apparatus for processing data for transmission in a wireless communication system using selective channel inversion. SOLUTION: The method includes: coding data based on a common coding and modulation scheme to provide modulation symbols; and pre-weighting the modulation symbols for each selected channel based on the channel's characteristics. The pre-weighting may be achieved by "inverting" the selected channels so that the received SNRs are approximately similar for all selected channels. With selective channel inversion, only channels having SNRs above a particular threshold are selected, "bad" channels are not used, and the total available transmit power is distributed across only "good" channels. COPYRIGHT: (C)2011,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To achieve transmission diversity on a legacy single-antenna receiving device. SOLUTION: In order to obtain transmission diversity, a transmission entity uses different pseudo-random steering vectors across subbands, and uses the same steering vector across packets for each subband. A receiving entity does not need to know the pseudo-random steering vectors and further does not need to perform any space processing. For space spreading, the transmission entity uses different pseudo-random steering vectors across the subbands and uses different steering vectors across the packets for each subband. Only the transmission and the receiving entities know the steering vectors used for data transmission. COPYRIGHT: (C)2010,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide an effective coding and modulation scheme capable of processing data before transmission on a channel. SOLUTION: Data are coded on the basis of a common coding and modulation scheme to provide modulation symbols and the modulation symbols for each selected channel are pre-weighted on the basis of channel's characteristics. The pre-weighting may be achieved by "inverting" the selected channels so that the received SNRs are approximately similar for all selected channels. With selective channel inversion, only channels having SNRs at or above a particular threshold are selected, "bad" channels are not used, and the total available transmit power is distributed across only "good" channels. Improved performance is achieved due to the combined benefits of using only the Ns best channels and matching the received SNR of each selected channel to the SNR required by the selected coding and modulation scheme. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide techniques for performing acquisition of packets.SOLUTION: First detection values are determined based on a first plurality of samples, e.g., by performing delay-multiply-integrate on the samples. Power values are determined based on the first plurality of samples, e.g., by performing multiply-integrate on the samples. The first detection values are averaged to obtain average detection values. The power values are also averaged to obtain average power values. Whether a packet is present is determined based on the average detection values and the average power values. Second detection values are determined based on a second plurality of samples. The start of the packet is determined based on the first and second detection values. A third detection value is determined based on a third plurality of samples. A frequency error of the packet is estimated based on the first and third detection values.
Abstract:
PROBLEM TO BE SOLVED: To provide techniques for performing phase correction for wireless communication.SOLUTION: Received pilot symbols and received data symbols are obtained from an orthogonal frequency division multiplexing (OFDM) and/or multiple-input multiple-output (MIMO) transmission. First phase information is obtained based upon the received pilot symbols. Second phase information is obtained based upon the received data symbols. The phase of the received data symbols is corrected based upon the first and second phase information (directly and/or indirectly). For example, the phase of the received data symbols may be corrected based upon the first phase information, detection may be performed on the phase corrected data symbols to obtain estimated data symbols, the second phase information may be obtained based upon the estimated data symbols, and the phase of the estimated data symbols may be corrected based upon the second phase information. The phase correction may also be performed in various manners.
Abstract:
PROBLEM TO BE SOLVED: To provide a method for supporting multiple spatial multiplexing (SM) modes.SOLUTION: For data transmission, multiple data streams are coded and modulated in accordance with their selected rates to obtain multiple data symbol streams. These streams are then spatially processed in accordance with a selected SM mode (e.g., with a matrix of steering vectors for the steered mode and with the identity matrix for the non-steered mode) to obtain multiple transmit symbol streams for transmission from multiple antennas. For data reception, multiple received symbol streams are spatially processed in accordance with the selected SM mode (e.g., with a matrix of eigenvectors for the steered mode and with a spatial filter matrix for the non-steered mode) to obtain multiple recovered data symbol streams. These streams are demodulated and decoded in accordance with their selected rates to obtain multiple decoded data streams.
Abstract:
PROBLEM TO BE SOLVED: To provide a technique for efficiently deriving a spatial filter matrix. SOLUTION: In a first scheme, a Hermitian matrix is iteratively derived, based on a channel response matrix, and a matrix inversion is calculated indirectly by iteratively deriving the Hermitian matrix. The spatial filter matrix is derived, based on the Hermitian matrix and the channel response matrix. In a second scheme, multiple rotations are performed to iteratively obtain first and second matrices for a pseudo-inverse matrix of the channel response matrix. The spatial filter matrix is derived based on the first and second matrices. In a third scheme, a matrix is formed based on the channel response matrix and decomposed to obtain a unitary matrix and a diagonal matrix. The spatial filter matrix is derived, based on the unitary matrix, the diagonal matrix and the channel response matrix. COPYRIGHT: (C)2011,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To maximize diversity for data transmission over as many dimensions as possible for obtaining strong characteristics. SOLUTION: For transmission diversity in a multi-antenna OFDM system, a transmitter encodes, interleaves, and symbol maps traffic data to obtain data symbols. The transmitter processes each pair of data symbols to obtain two pairs of transmission symbols for transmission from a pair of antennas either (1) in two OFDM symbol periods for space-time transmission diversity or (2) on two subbands for space-frequency transmission diversity. N T (N T -1)/2 different antenna pairs are used for data transmission, along with different antenna pairs being used for adjacent subbands, where N T is the number of antennas. The system may support multiple OFDM symbol sizes. COPYRIGHT: (C)2011,JPO&INPIT
Abstract translation:要解决的问题:为了最大限度地实现数据传输的分集,尽可能多的尺寸以获得强的特性。 解决方案:对于多天线OFDM系统中的发射分集,发射机对业务数据进行编码,交织和符号映射以获得数据符号。 发射机处理每对数据符号以获得两对传输符号,用于在两个用于空时传输分集的OFDM符号周期中的一个天线(1)或(2)用于空间 - 频率传输分集的两个子带上从一对天线发射 。 N T SB>(N T SB> -1)/ 2个不同的天线对用于数据传输,以及不同的天线对用于相邻子带,其中N T SB>是天线的数量。 该系统可以支持多个OFDM符号大小。 版权所有(C)2011,JPO&INPIT