公开(公告)号：US06374375B1

公开(公告)日：2002-04-16

申请号：US08853300

申请日：1997-05-09

Applicant: Philip C. Yip ,  Muhammad M. Rahmatullah ,  Terry L. Cole

Inventor： Philip C. Yip ,  Muhammad M. Rahmatullah ,  Terry L. Cole

IPC: G01R3128

CPC classification number: H04L1/242 ,  H04L1/241

Abstract: A method and apparatus for allowing a modem transmitting data in the data mode to initiate retraining mode due to changing line conditions. The modem inserts a test signal within the data received from a computer system. The data and test signal are encoded and sent over a network to a second modem. The second modem compares the test signal with a standard test signal, and if the test signal received is different from the standard test signal, the second modem initiates retraining of the modems to adjust for the varying line conditions.

Abstract translation: 一种用于允许调制解调器在数据模式中发送数据以由于改变线路条件而发起再训练模式的方法和装置。 调制解调器将测试信号插入到从计算机系统接收的数据中。 数据和测试信号被编码并通过网络发送到第二调制解调器。 第二调制解调器将测试信号与标准测试信号进行比较，并且如果接收的测试信号与标准测试信号不同，则第二调制解调器启动调制解调器的再训练以针对变化的线路条件进行调整。

公开(公告)号：US06195782B1

公开(公告)日：2001-02-27

申请号：US09086098

申请日：1998-05-28

Applicant: Muhammad M. Rahmatullah ,  Tony E. Sawan ,  Philip Yip

Inventor： Muhammad M. Rahmatullah ,  Tony E. Sawan ,  Philip Yip

IPC: H03M1303

CPC classification number: H03M13/6331 ,  H03M13/3961 ,  H03M13/41 ,  H03M13/6502 ,  H03M13/6569 ,  H04L1/0054

Abstract: A digital signal processor (DSP), hardware module, and shared memory coupled together to perform Viterbi decoding on a sequence of received symbols. Given channel coefficients, the DSP calculates initial data for Viterbi processing: combination values for each possible state and branch product values for each possible symbol. These values are stored in shared memory for access by the hardware module. The DSP further calculates the first few stages of the Viterbi processing so path metrics are well defined for every state. Path metric values are also stored into the shared memory. The hardware module is optimized to perform calculations associated with a single stage of the Viterbi algorithm. The DSP invokes by the hardware module by passing a received sample to the hardware module. The hardware module calculates a survivor state value and minimizing path metric value for each state in the state space.

Abstract translation: 耦合在一起的数字信号处理器（DSP），硬件模块和共享存储器，对接收的符号序列执行维特比解码。 给定通道系数，DSP计算维特比处理的初始数据：每个可能状态的组合值和每个可能符号的分支乘积值。 这些值存储在共享存储器中以供硬件模块访问。 DSP进一步计算维特比处理的前几个阶段，因此每个状态都很好地定义了路径度量。 路径度量值也存储在共享存储器中。 硬件模块被优化以执行与维特比算法的单级相关联的计算。 通过将接收到的样本传递到硬件模块，DSP由硬件模块调用。 硬件模块计算状态空间中的每个状态的幸存状态值并最小化路径度量值。

公开(公告)号：US6026130A

公开(公告)日：2000-02-15

申请号：US853430

申请日：1997-05-09

Applicant: Muhammad M. Rahmatullah ,  Philip Yip ,  Saf Asghar

Inventor： Muhammad M. Rahmatullah ,  Philip Yip ,  Saf Asghar

IPC: H04L25/02 ,  H03D1/00 ,  H04L27/14

CPC classification number: H04L25/0228

Abstract: The present invention comprises a system and method for a GSM receiver to perform channel estimation under the assumption that the analog-to-digital (A/D) converter is free-running. A search process is employed, whereby the known GSM training signal is sampled with a plurality of phases which vary incrementally from zero to a full symbol period. For each phase a sample set (of the training signal) is generated. Furthermore, each sample set is used, together with the received samples, in a cross-correlation procedure to obtain a candidate impulse response vector for the transmission channel. Thus a plurality of candidate impulse response vectors are produced, one of which will be selected to be the optimal representative for the transmission channel. The optimal impulse response vector is selected as follows. Each impulse response vector is convolved with the corresponding sample set, thus producing an estimated output vector. The estimated output vectors are compared with the vector of received samples (from the free-running A/D converter), and the estimated output vector which is closest in the Euclidean (square-norm) sense designates the impulse response vector which is optimal.

Abstract translation: 本发明包括一种GSM接收机在假设模数（A / D）转换器自由运行的情况下执行信道估计的系统和方法。 采用搜索过程，由此已知的GSM训练信号以从零到全符号周期递增地变化的多个相位进行采样。 对于每个阶段，生成样本集（训练信号的）。 此外，每个样本集合与接收的样本一起用于互相关过程以获得用于传输信道的候选脉冲响应向量。 因此，产生多个候选脉冲响应向量，其中之一将被选择为传输信道的最佳代表。 最佳脉冲响应向量选择如下。 每个脉冲响应向量与对应的采样集进行卷积，从而产生估计的输出向量。 将估计的输出矢量与接收样本的矢量（来自自由运行的A / D转换器）进行比较，并且在欧几里得（方差）方向上最接近的估计输出矢量表示最佳的脉冲响应矢量。