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    • 3. 发明授权
    • Rate adaptive transmission scheme for MIMO systems
    • MIMO系统速率自适应传输方案
    • US08619717B2
    • 2013-12-31
    • US12690307
    • 2010-01-20
    • Avneesh AgrawalRajiv VijayanTamer Kadous
    • Avneesh AgrawalRajiv VijayanTamer Kadous
    • H04B7/00
    • H04L1/0618H04B7/0417H04B7/0443H04B7/0465H04B7/0615H04B7/0891H04W52/34H04W52/42
    • A rate adaptive transmission scheme for MIMO systems, which can transmit a variable number of data symbol streams, provide transmit diversity for each data symbol stream, and fully utilize the total transmit power of the system and the full power of each antenna. In one method, at least one data symbol stream is received for transmission from a plurality of antennas. Each data symbol stream is scaled with a respective weight corresponding to the amount of transmit power allocated to that stream. The scaled data symbol stream(s) are multiplied with a transmit basis matrix to provide a plurality of transmit symbol streams for the plurality of antennas. The transmit basis matrix (e.g., a Walsh-Hadamard matrix or a DFT matrix) is defined such that each data symbol stream is transmitted from all antennas and each transmit symbol stream is transmitted at (or near) the full power for the associated antenna.
    • 可以传输可变数量的数据符号流的MIMO系统的速率自适应传输方案为每个数据符号流提供发射分集,并且充分利用系统的总发射功率和每个天线的全功率。 在一种方法中,接收至少一个数据符号流用于从多个天线发射。 每个数据符号流用对应于分配给该流的发射功率的量的相应权重进行缩放。 缩放的数据符号流与发射基矩阵相乘以为多个天线提供多个发射符号流。 定义发射基矩阵(例如,沃尔什 - 哈达玛矩阵或DFT矩阵),使得每个数据符号流从所有天线发送,并且每个发射符号流以(或接近)相关天线的全功率发射。
    • 4. 发明申请
    • METHOD AND APPARATUS FOR ANTENNA DIVERSITY IN MULTI-INPUT MULTI-OUTPUT COMMUNICATION SYSTEMS
    • 多输入多输出通信系统中天线多样性的方法与装置
    • US20120120925A1
    • 2012-05-17
    • US13271121
    • 2011-10-11
    • Tamer KadousAamod KhandekarDhananjay Ashok GoreAlexei Gorokhov
    • Tamer KadousAamod KhandekarDhananjay Ashok GoreAlexei Gorokhov
    • H04W72/04
    • H04L5/0023H04B7/0456H04B7/061H04B7/0671H04B7/0691H04B7/0697H04L27/2602
    • Transmission schemes that can flexibly achieve the desired spatial multiplexing order, spatial diversity order, and channel estimation overhead order are described. For data transmission, the assigned subcarriers and spatial multiplexing order (M) for a receiver are determined, where M≧1. For each assigned subcarrier, M virtual antennas are selected from among V virtual antennas formed with V columns of an orthonormal matrix, where V≧M. V may be selected to achieve the desired spatial diversity order and channel estimation overhead order. Output symbols are mapped to the M virtual antennas selected for each assigned subcarrier by applying the orthonormal matrix. Pilot symbols are also mapped to the V virtual antennas. The mapped symbols are provided for transmission from T transmit antennas, where T≧V. Transmission symbols are generated for the mapped symbols, e.g, based on OFDM or SC-FDMA. Different cyclic delays may be applied for the T transmit antennas to improve diversity.
    • 描述了可以灵活地实现期望的空间复用顺序,空间分集顺序和信道估计开销顺序的传输方案。 对于数据传输,确定接收机的分配子载波和空间复用顺序(M),其中M≥1。 对于每个分配的子载波,从由正交矩阵的V列形成的V个虚拟天线中选择M个虚拟天线,其中V≥M。 可以选择V以实现期望的空间分集顺序和信道估计开销顺序。 通过应用正交矩阵将输出符号映射到为每个分配的副载波选择的M个虚拟天线。 导频符号也映射到V虚拟天线。 映射的符号被提供用于从T发射天线发射,其中T≥V。 为映射符号生成传输符号,例如基于OFDM或SC-FDMA。 可以对T发射天线应用不同的循环延迟以改善分集。
    • 6. 发明授权
    • Successive interference cancellation receiver processing with selection diversity
    • 连续干扰消除接收机处理与选择分集
    • US07890144B2
    • 2011-02-15
    • US12257200
    • 2008-10-23
    • Anand D. SubramaniamTamer Kadous
    • Anand D. SubramaniamTamer Kadous
    • H04B1/38H04B17/00
    • H04L1/0687H04B7/0602H04B7/0802H04L1/0003H04L1/0009
    • Techniques are provided to support successive interference cancellation (SIC) receiver processing with selection diversity whereby each of NT transmit antennas may be turned on or off. One symbol stream may be transmitted from each transmit antenna. A SIC receiver recovers the transmitted symbol streams in a specific order. Up to NT! orderings are evaluated. For each ordering, NT post-detection SNRs are obtained for NT transmit antennas and used to determine NT data rates, where the data rate is zero if the post-detection SNR is worse than a minimum required SNR. An overall data rate is computed for each ordering based on the NT data rates. The ordering with the highest overall data rate is selected for use. Up to NT symbol streams are processed at the data rates for the selected ordering and transmitted. The transmitted symbol streams are recovered in accordance with the selected ordering.
    • 技术被提供以支持具有选择分集的连续干扰消除(SIC)接收机处理,从而可以打开或关闭每个NT个发射天线。 一个符号流可以从每个发送天线发送。 SIC接收器以特定顺序恢复发送的符号流。 达NT! 对订单进行评估。 对于每个排序,对于NT个发射天线获得NT后检测SNR,并且用于确定NT数据速率,其中如果后检测SNR比最小所需SNR更差,则数据速率为零。 基于NT数据速率对每个排序计算总体数据速率。 选择具有最高总数据速率的排序使用。 最多NT个符号流以所选择的排序和传输的数据速率进行处理。 所发送的符号流根据所选择的顺序被恢复。
    • 7. 发明授权
    • Channel estimation for OFDM communication systems
    • OFDM通信系统的信道估计
    • US07463576B2
    • 2008-12-09
    • US11101908
    • 2005-04-07
    • Ranganathan KrishnanTamer Kadous
    • Ranganathan KrishnanTamer Kadous
    • H04J11/00
    • H04W52/325H04L25/0212H04L25/022H04L25/023H04W52/24H04W52/34H04W52/42
    • Techniques to estimate the frequency response of a wireless channel in an OFDM system. In one method, an initial estimate of the frequency response of the wireless channel is obtained for a first group of subbands based on a pilot transmission received via the subbands in the first group. An estimate of the impulse response of the wireless channel is then derived based on the initial frequency response estimate. An enhanced estimate of the frequency response of the wireless channel is then derived for a second group of subbands based on the impulse response estimate. The first and second groups may each include all or only a subset of the usable subbands. Subband multiplexing may be used to allow simultaneous pilot transmissions by multiple terminals on their associated groups of subbands.
    • 估计OFDM系统中无线信道的频率响应的技术。 在一种方法中,基于经由第一组中的子带接收的导频传输,针对第一组子带获得无线信道的频率响应的初始估计。 然后基于初始频率响应估计推导出无线信道的脉冲响应的估计。 然后基于脉冲响应估计对第二组子带导出对无线信道的频率响应的增强估计。 第一组和第二组可以各自包括全部或仅一个可用子带的子集。 子带复用可用于允许在其相关联的子带组上的多个终端的同时导频传输。
    • 8. 发明申请
    • PILOT TRANSMISSION AND CHANNEL ESTIMATION FOR MULTIPLE TRANSMITTERS
    • 多台发射机的导频传输和信道估计
    • US20080112495A1
    • 2008-05-15
    • US11873375
    • 2007-10-16
    • Dhananjay Ashok GoreAvneesh AgrawalTamer Kadous
    • Dhananjay Ashok GoreAvneesh AgrawalTamer Kadous
    • H04K1/10
    • H04L25/0204H04L25/0212H04L25/0226H04L27/261
    • Each transmitter is assigned a time-only pilot code, a frequency-only pilot code, or a time-frequency pilot code to use for pilot transmission. The pilot codes may be pseudo-random, orthogonal, and/or cyclic-shift codes. To obtain a channel estimate for a transmitter using a time-frequency pilot code composed of a time-only code and a frequency-only code, a receiver multiplies a set of received symbols for each symbol period with a set of code values for the frequency-only code to obtain a set of detected symbols and performs an IDFT on the set of detected symbols to obtain an initial impulse response estimate. The receiver performs code matching on multiple initial impulse response estimates derived for multiple symbol periods with the time-only code to obtain a final impulse response estimate for the desired transmitter. The receiver retains the first L channel taps and zeroes out remaining channel taps, where L is the expected channel length.
    • 为每个发射机分配一个仅时间导频码,仅频率导频码或用于导频传输的时频导频码。 导频码可以是伪随机,正交和/或循环移位码。 为了使用由时间唯一码和仅频率码构成的时频导频码来获得用于发射机的信道估计,接收机将用于每个符号周期的一组接收符号与频率的一组码值相乘 - 获得一组检测符号的代码,并对检测符号集合执行IDFT以获得初始脉冲响应估计。 接收机对具有多个符号周期的多个初始脉冲响应估计执行码匹配,其中仅使用时间码来获得所需发射机的最终脉冲响应估计。 接收器保留第一个L个通道抽头,并将剩余的通道抽头置零,其中L是预期的通道长度。