Link adaptation for OFDM systems
    61.
    发明授权
    Link adaptation for OFDM systems 有权
    OFDM系统的链路适配

    公开(公告)号:US08681888B1

    公开(公告)日:2014-03-25

    申请号:US13619523

    申请日:2012-09-14

    IPC分类号: H04L27/28

    摘要: A method includes determining one or more metrics indicative of at least one of (i) interference on a communication link, (ii) noise on the communication link, and (iii) performance of a receiver receiving packets via the communication link, selecting a modulation and coding scheme as a function of (i) the determined one or more metrics, and (ii) one or more Quality of Service requirements for the communication link, and correcting the selected modulation and coding scheme using a current value of a correction factor. The corrected modulation and coding scheme is to be used to generate one or more packets. The method also includes determining an error rate corresponding to packets previously transmitted over the communication link, and adjusting the correction factor based on the determined error rate. Adjusting the correction factor includes incrementing or decrementing the correction factor.

    摘要翻译: 一种方法包括确定一个或多个度量,其指示以下中的至少一个:(i)通信链路上的干扰,(ii)通信链路上的噪声,以及(iii)经由通信链路接收分组的接收机的性能,选择调制 以及作为(i)确定的一个或多个度量的函数的编码方案,以及(ii)通信链路的一个或多个服务质量要求,以及使用校正因子的当前值来校正所选择的调制和编码方案。 校正的调制和编码方案将用于生成一个或多个分组。 该方法还包括确定对应于先前通过通信链路发送的分组的错误率,以及基于所确定的错误率来调整校正因子。 调整校正因子包括增加或减少校正因子。

    BICM decoding in the presence of co-channel interference
    62.
    发明授权
    BICM decoding in the presence of co-channel interference 有权
    在存在同频道干扰的情况下进行BICM解码

    公开(公告)号:US08654902B2

    公开(公告)日:2014-02-18

    申请号:US13402381

    申请日:2012-02-22

    IPC分类号: H04L27/06

    CPC分类号: H04B1/1027 H04L25/067

    摘要: Systems and methods are provided for computing soft information for digital information based on a received signal, where the received signal suffers from noise and interference. A receiver that decodes the received signal may estimate channel information, such as the channel gain, associated with the interfering source. The receiver may also obtain modulation information through a backbone network or by decoding control information transmitted by the interfering source. Using the modulation information and the channel information, the receiver may estimate the effect that interference has on the received signal, and may compute soft information (e.g., a log-likelihood ratio) for the digital information.

    摘要翻译: 提供了系统和方法,用于基于接收到的信号来计算用于数字信息的软信息,其中所接收的信号受到噪声和干扰的影响。 对接收到的信号进行解码的接收机可以估计与干扰源相关联的信道信息,例如信道增益。 接收机还可以通过骨干网获得调制信息,或通过解码由干扰源发送的控制信息。 使用调制信息和信道信息,接收机可以估计干扰对接收信号的影响,并且可以计算数字信息的软信息(例如,对数似然比)。

    Frame synchronization method and apparatus
    63.
    发明授权
    Frame synchronization method and apparatus 有权
    帧同步方法和装置

    公开(公告)号:US08488698B1

    公开(公告)日:2013-07-16

    申请号:US13194093

    申请日:2011-07-29

    IPC分类号: H04K1/10 H04L27/28

    CPC分类号: H04L27/2656 H04L27/2676

    摘要: In a method for synchronizing a receiver to a synchronous signal, in a signal having been processed based on an automatic gain control (AGC) with a varying gain, a symbol is detected. An estimated beginning of a subsequent frame is determined based on the detected symbol. A gain of the AGC is fixed for a period during which the estimated start of the subsequent frame is processed by the AGC. A transform of the signal is analyzed to determine if the estimated start of the subsequent frame corresponds to an actual start of the subsequent frame. If the estimated start of the subsequent frame does not corresponds to the actual start of the subsequent frame, the gain of the AGC is allowed to resume varying and, a further symbol in the signal is detected, the signal having been processed based on the varying gain of the AGC.

    摘要翻译: 在用于将接收机同步到同步信号的方法中,在基于具有变化增益的自动增益控制(AGC)处理的信号中,检测到符号。 基于检测到的符号确定后续帧的估计开始。 AGC的增益在AGC期间处理后续帧的估计开始的期间是固定的。 分析信号的变换以确定后续帧的估计开始是否对应于后续帧的实际开始。 如果后续帧的估计开始不对应于后续帧的实际开始,则允许AGC的增益恢复变化,并且检测到信号中的另外的符号,该信号已经根据变化 增益AGC。

    Physical layer data unit format
    64.
    发明授权
    Physical layer data unit format 有权
    物理层数据单元格式

    公开(公告)号:US08477813B2

    公开(公告)日:2013-07-02

    申请号:US12548205

    申请日:2009-08-26

    IPC分类号: H04J3/06

    摘要: In a wireless communication system wherein communication devices exchange information utilizing data units that conform to a first format, a beamforming training (BFT) data unit that conforms to a second format is transmitted, wherein a length of the BFT data unit is shorter than lengths supported by the first format, wherein the BFT data unit is for transmitting PHY beamforming training information. Information to indicate the BFT data unit conforms to the second format is transmitted to a receiving device. The BFT data unit is generated according to the second format, wherein the BFT data unit includes BFT information elements. The BFT data unit is then transmitted to the receiving device.

    摘要翻译: 在其中通信设备利用符合第一格式的数据单元交换信息的无线通信系统中,发送符合第二格式的波束形成训练(BFT)数据单元,其中所述BFT数据单元的长度短于所支持的长度 通过第一格式,其中BFT数据单元用于发送PHY波束形成训练信息。 用于指示符合第二格式的BFT数据单元的信息被发送到接收设备。 BFT数据单元根据第二格式生成,其中BFT数据单元包括BFT信息元素。 然后将BFT数据单元发送到接收设备。

    Methods, algorithms, software, circuits, receivers and systems for decoding convolutional code

    公开(公告)号:US08443272B1

    公开(公告)日:2013-05-14

    申请号:US13473165

    申请日:2012-05-16

    IPC分类号: H03M13/03

    摘要: Methods, software, circuits and systems involving a low complexity, tailbiting decoder. In various embodiments, the method relates to concatenating an initial and/or terminal subblock of the serial data block and outputting decoded data from an internal block of the modified data block. The circuitry generally includes a buffer, logic configured to concatenate an initial and/or terminal subblock to the serial data block, and a decoder configured to decode the data block, estimate starting and ending states for the data block, and output an internal portion of the serial data block and the one or more sequences as decoded data. The invention advantageously reduces the complexity of a suboptimal convolutional decoder, ensures smooth transitions at the beginning and end of the serial data block during decoding, and increases the reliability of the starting and ending states, without adding overhead to the transmitted data block.

    Method and apparatus for receiving signals in a MIMO system with multiple channel encoders

    公开(公告)号:US08411806B1

    公开(公告)日:2013-04-02

    申请号:US12543363

    申请日:2009-08-18

    IPC分类号: H04L27/06

    摘要: In a method for decoding plurality of information streams corresponding to a plurality of layers, where the plurality of information streams have been transmitted via a multiple input multiple output (MIMO) communication channel, a plurality of received signals are processed to decode information corresponding to a first layer. A plurality of modified received signals are generated using the decoded information corresponding to the first layer and the plurality of received signals. Bit metric values are generated for a second layer using MIMO maximum likelihood (ML) demodulation and using the plurality of modified received signals and channel and modulation information for interfering signals. Information corresponding to the second layer is decoded using the generated bit metric values.

    Robust synchronization and detection mechanisms for OFDM WLAN systems
    67.
    发明授权
    Robust synchronization and detection mechanisms for OFDM WLAN systems 有权
    OFDM WLAN系统的鲁棒同步和检测机制

    公开(公告)号:US08369469B1

    公开(公告)日:2013-02-05

    申请号:US13085350

    申请日:2011-04-12

    IPC分类号: H04L25/08

    摘要: A method including: receiving, through a wireless channel, a plurality of modulated signals at a plurality of antennas, wherein each antenna receives a corresponding modulated signal; generating a plurality of autocorrelated signals by autocorrelating the plurality of modulated signals; determining whether a signal strength associated with each modulated signal is (i) below a threshold or (ii) above the threshold; for each modulated signal having a signal strength below the threshold, disabling the antenna that received the modulated signal having the signal strength below the threshold; combining the modulated signals having a signal strength above the threshold; generating weighted autocorrelated signals based on (i) the plurality of autocorrelated signals and (ii) the combined modulated signals; generating a combined weighted signal by summing the weighted autocorrelation signals; demodulating the combined weighted signal; and determining a state of the wireless channel based on the demodulation of the combined weighted signal.

    摘要翻译: 一种方法,包括:通过无线信道在多个天线处接收多个调制信号,其中每个天线接收对应的调制信号; 通过对所述多个调制信号进行自相关来生成多个自相关信号; 确定与每个调制信号相关联的信号强度是否是(i)低于阈值或(ii)高于阈值; 对于具有低于阈值的信号强度的每个调制信号,禁用接收到信号强度低于阈值的调制信号的天线; 组合具有高于阈值的信号强度的调制信号; 基于(i)所述多个自相关信号和(ii)所述组合调制信号产生加权自相关信号; 通过对加权的自相关信号求和来产生组合的加权信号; 解调组合加权信号; 以及基于所述组合加权信号的解调来确定所述无线信道的状态。

    Adaptive OFDM receiver based on carrier frequency offset
    68.
    发明授权
    Adaptive OFDM receiver based on carrier frequency offset 有权
    基于载波频偏的自适应OFDM接收机

    公开(公告)号:US08311152B1

    公开(公告)日:2012-11-13

    申请号:US10986110

    申请日:2004-11-10

    CPC分类号: H04L27/2657 H04B7/01

    摘要: An adaptive receiver comprises a receiver module that receives an orthogonal frequency division multiplexing (OFDM) signal. An operating parameters module monitors at least one operating parameter of the receiver module and generates a select signal based the at least one operating parameter. An estimator module selects between first and second algorithms based on the select signal and selectively estimates a carrier frequency offset (CFO) of the OFDM signal using the one of the first and second algorithms. Alternately, an estimator module adjusts algorithm operating parameters of a first algorithm based on the select signal and selectively estimates a carrier frequency offset (CFO) of the OFDM signal using the selected algorithm operating parameters of the first algorithm.

    摘要翻译: 自适应接收机包括接收正交频分复用(OFDM)信号的接收机模块。 操作参数模块监视接收机模块的至少一个操作参数,并基于该至少一个操作参数生成选择信号。 估计器模块基于选择信号在第一和第二算法之间进行选择,并且使用第一和第二算法之一选择性地估计OFDM信号的载波频率偏移(CFO)。 或者,估计器模块基于选择信号来调整第一算法的算法运行参数,并且使用所选择的算法运算参数选择性地估计OFDM信号的载波频率偏移(CFO)。

    Detector for single-user coded signals in the presence of interference
    69.
    发明授权
    Detector for single-user coded signals in the presence of interference 有权
    在有干扰的情况下用于单用户编码信号的检测器

    公开(公告)号:US08279980B1

    公开(公告)日:2012-10-02

    申请号:US12468631

    申请日:2009-05-19

    IPC分类号: H04L27/06

    摘要: Techniques are provided for detecting a coded signal in the presence of interference. In an embodiment, a primary transmitter corresponds to a desired transmitter, and one or more secondary transmitters correspond to interfering transmitters. Received symbols, which include interference and additive noise, are filtered to recover a set of original message bits. An estimate of the set of original message bits may be determined using an ordered successive interference cancellation (SIC) decoder that uses either a SIC detector or an AWGN-based detector, depending on the signal-to-interference ratio at a primary receiver.

    摘要翻译: 提供了用于在存在干扰的情况下检测编码信号的技术。 在一个实施例中,主发射机对应于期望的发射机,并且一个或多个次发射机对应于干扰发射机。 接收到的包括干扰和加性噪声的符号被过滤以恢复一组原始消息位。 可以使用使用SIC检测器或基于AWGN的检测器的有序连续干扰消除(SIC)解码器来确定原始消息比特组的估计,这取决于主接收机处的信号干扰比。

    Preamble detection with multiple receive antennas
    70.
    发明授权
    Preamble detection with multiple receive antennas 有权
    使用多个接收天线进行前导码检测

    公开(公告)号:US08238493B1

    公开(公告)日:2012-08-07

    申请号:US13225054

    申请日:2011-09-02

    IPC分类号: H03D1/00

    摘要: A system including a differential demodulation module, a first summing module, and a second summing module. The differential demodulation module generates differentially demodulated signals based on having differentially demodulated received signals. The first summing module generates a combined signal by adding the differentially demodulated signals, wherein the combined signal includes a plurality of symbols. The second summing module generates a plurality of sums for each of a plurality of derived preamble sequences, wherein the derived preamble sequences are derived from preamble sequences, and wherein each of the derived preamble sequences includes a plurality of derived symbols. The second summing module further generates cross-correlation values for the derived preamble sequences based on the plurality of sums, wherein one of the cross-correlation values generated for one of the derived preamble sequences is a sum of the plurality of sums generated for the one of the derived preamble sequences.

    摘要翻译: 一种包括差分解调模块,第一求和模块和第二求和模块的系统。 差分解调模块基于具有差分解调的接收信号产生差分解调信号。 第一求和模块通过加入差分解调信号来产生组合信号,其中组合信号包括多个符号。 第二求和模块针对多个导出的前同步码序列中的每一个生成多个和,其中所导出的前同步码序列从前导码序列导出,并且其中所导出的前导码序列中的每一个包括多个导出符号。 第二求和模块还基于多个和来产生所导出的前同步码序列的互相关值,其中为所导出的前导码序列中的一个生成的互相关值中的一个是为该一个生成的多个和之和 的导出前导​​码序列。