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1. 发明授权

US5467374A Low complexity adaptive equalizer for U.S. digital cellular radio receivers 失效
标题翻译：用于美国数字蜂窝无线电接收机的低复杂度自适应均衡器
公开(公告)号：US5467374A
公开(公告)日：1995-11-14
申请号：US143028
申请日：1993-10-29
申请人： Sandeep Chennakeshu , Paul W. Dent , Ravinder D. Koilpillai , Raymond L. Toy
发明人： Sandeep Chennakeshu , Paul W. Dent , Ravinder D. Koilpillai , Raymond L. Toy
IPC分类号： H04L25/03 , H03D1/00
CPC分类号： H04L25/03197 , H04L2025/0356 , H04L2025/03796
摘要： A low complexity adaptive equalizer for use in U.S. digital cellular radios demodulates .pi./4-shifted differentially encoded quadrature phase shift keyed (DQPSK) encoding in the presence of intersymbol interference (ISI) with reduced decoding complexity by employing an estimated received constellation which takes into account channel changes over time and ISI. The decoding complexity is reduced by tracking a reduced number of estimated reference constellation points and taking advantage of the geometry to estimate the remaining symbol constellation points. A slot of symbols is decoded, employing unique filtering, in segments from the beginning in a forward direction and from the end in a reverse direction meeting at a fade point. This isolates a fade and allows the equalizer to perform more reliably.
摘要翻译：用于美国数字蜂窝无线电的低复杂度自适应均衡器在存在码间干扰（ISI）的情况下，通过采用估计的接收星座来解调具有降低的解码复杂度的π/ 4位差分编码正交相移键控（DQPSK）编码帐户频道随时间变化和ISI。通过跟踪估计的参考星座点的数量减少并利用几何来估计剩余的符号星座点来降低解码复杂度。符号的时隙被解码，采用独特的滤波，从开始的前进方向开始，并且在反向方向的结束处，在渐变点处会聚。这样隔离了一个淡入淡出，并允许均衡器执行得更可靠。

2. 发明授权

US5488635A Low complexity adaptive equalizer radio receiver employing reduced complexity branch metric calculation 失效
标题翻译：低复杂度自适应均衡器无线电接收机采用降低复杂度的分支度量计算
公开(公告)号：US5488635A
公开(公告)日：1996-01-30
申请号：US143027
申请日：1993-10-29
申请人： Sandeep Chennakeshu , Ravinder D. Koilpillai , Raymond L. Toy
发明人： Sandeep Chennakeshu , Ravinder D. Koilpillai , Raymond L. Toy
IPC分类号： H04L25/03 , H03D1/00 , H04L27/06
CPC分类号： H04L25/03197 , H04L2025/03401 , H04L2025/03796
摘要： A low complexity adaptive equalizer for use in U.S. digital cellular radios demodulates .pi./4-shifted differentially encoded quadrature phase shift keyed (DQPSK) encoding in the presence of intersymbol interference (ISI) with reduced decoding complexity by employing an estimated received constellation which takes into account channel changes over time and ISI. The complexity is reduced by tracking a reduced number of estimated reference symbol constellation points and taking advantage of the geometry to estimate the remaining symbol constellation points. Branch metrics are also determined with a reduced number of computations.
摘要翻译：用于美国数字蜂窝无线电的低复杂度自适应均衡器在存在码间干扰（ISI）的情况下，通过采用估计的接收星座来解调具有降低的解码复杂度的π/ 4位差分编码正交相移键控（DQPSK）编码帐户频道随时间变化和ISI。通过跟踪减少数量的估计参考符号星座点并利用几何来估计剩余的符号星座点来减少复杂度。分支度量也用减少的计算数量确定。

3. 发明授权

US5406593A Adaptive phase-locked loop employing channel state information estimation from received signal phase angles 失效
标题翻译：自适应锁相环采用信道状态信息估计从接收信号相位角
公开(公告)号：US5406593A
公开(公告)日：1995-04-11
申请号：US109554
申请日：1993-08-20
申请人： Sandeep Chennakeshu , Ravinder D. Koilpillai , Raymond L. Toy
发明人： Sandeep Chennakeshu , Ravinder D. Koilpillai , Raymond L. Toy
IPC分类号： H04B7/08 , H04L1/20 , H03D3/24
CPC分类号： H04B7/082 , H04L1/20
摘要： A method of estimating the quality of a communication channel from a differential phase angle between a received signal and the corresponding transmitted phase angle employs determining a signal to impairment ratio (SIR) as an indicator of channel state information (CSI). A maximum likelihood estimation procedure is employed to calculate this CSI metric as a function of the differential phase angle between the received signal and transmitted signal. An alternate embodiment employs a estimation that incorporates average SIR information for a Rayleigh fading channel. Since CSI is derived from the phase angle of the received signal, and does not require signal amplitude information, it is attractive for use with differential detectors, phase-locked loops (PLLs) and hard-limited signals. The CSI provided can be used for implementing post detection selection diversity, by selecting the signal from a plurality of antennae which has the best SIR.
摘要翻译：从接收信号和对应的发射相位角之间的差分相位角估计通信信道的质量的方法使用将信号衰减比（SIR）确定为信道状态信息（CSI）的指示符。采用最大似然估计程序来计算该CSI度量作为接收信号和发射信号之间的差分相位角的函数。替代实施例采用了一种包含瑞利衰落信道的平均SIR信息的估计。由于CSI是从接收信号的相位角导出的，并且不需要信号幅度信息，因此与差分检测器，锁相环（PLL）和硬限制信号一起使用是有吸引力的。所提供的CSI可以用于通过选择具有最佳SIR的多个天线的信号来实现后检测选择分集。

4. 发明授权

US5371471A Low complexity adaptive equalizer radio receiver employing direct reference state updates 失效
标题翻译：采用直接参考状态更新的低复杂度自适应均衡器无线电接收机
公开(公告)号：US5371471A
公开(公告)日：1994-12-06
申请号：US143011
申请日：1993-10-29
申请人： Sandeep Chennakeshu , Ravinder D. Koilpillai , Raymond L. Toy
发明人： Sandeep Chennakeshu , Ravinder D. Koilpillai , Raymond L. Toy
IPC分类号： H04L25/02 , H04L25/03 , H04L27/12
CPC分类号： H04L25/0236 , H04L2025/03401 , H04L25/03178
摘要： A low complexity adaptive equalizer for use in U.S. digital cellular radios demodulates .pi./4-shifted differentially encoded quadrature phase shift keyed (DQPSK) encoding in the presence of intersymbol interference (ISI) with reduced decoding complexity by employing an estimated received constellation which takes into account channel changes over time and ISI. The decoding complexity is reduced by tracking a reduced number of estimated reference symbol constellation points and taking advantage of the geometry to estimate the remaining symbol constellation points. Reference symbol constellation points are updated directly to compensate for changes in the channel, instead of determining channel impulse response (CIR) coefficients, and convolving the CIR coefficients with received symbols to determine new reference symbol constellation points.
摘要翻译：用于美国数字蜂窝无线电的低复杂度自适应均衡器在存在码间干扰（ISI）的情况下，通过采用估计的接收星座来解调具有降低的解码复杂度的π/ 4位差分编码正交相移键控（DQPSK）编码帐户频道随时间变化和ISI。通过跟踪估计的参考符号星座点的数量减少并利用几何来估计剩余的符号星座点来减少解码复杂度。参考符号星座点被直接更新以补偿信道中的变化，而不是确定信道脉冲响应（CIR）系数，并且将CIR系数与接收的符号进行卷积以确定新的参考符号星座点。

5. 发明授权

US5343498A Sample timing selection and frequency offset correction for U.S. digital cellular mobile receivers 失效
标题翻译：美国数字蜂窝移动接收机的采样定时选择和频偏校正
公开(公告)号：US5343498A
公开(公告)日：1994-08-30
申请号：US028016
申请日：1993-03-08
申请人： Raymond L. Toy , Ravinder D. Koilpillai , Sandeep Chennakeshu
发明人： Raymond L. Toy , Ravinder D. Koilpillai , Sandeep Chennakeshu
IPC分类号： H04L7/02 , H04L7/04 , H04L27/00
CPC分类号： H04L7/0062 , H04L7/042
摘要： A Time Division Multiple Access (TDMA) radio system achieves synchronization by performing a two-step synchronization. A simplified frame/slot synchronization is followed by a symbol synchronization of higher accuracy. This symbol timing is passed to a frequency offset unit which determines the amount of frequency drift between the transmitter and receiver and compensates for the frequency drift. This results in improved receiver performance for the TDMA digital radio system.
摘要翻译：时分多址（TDMA）无线电系统通过执行两步同步来实现同步。简化的帧/时隙同步之后是更高精度的符号同步。该符号定时被传递到频率偏移单元，其确定发射机和接收机之间的频率漂移量并补偿频率漂移。这导致TDMA数字无线电系统的接收机性能得到改善。

6. 发明授权

US5400362A Double sided slot traversing decoding for time division multiple access (TDMA) radio systems 失效
标题翻译：用于时分多址（TDMA）无线电系统的双面时隙遍历解码
公开(公告)号：US5400362A
公开(公告)日：1995-03-21
申请号：US39599
申请日：1993-03-29
申请人： Sandeep Chennakeshu , Raymond L. Toy , Ravinder D. Koilpillai
发明人： Sandeep Chennakeshu , Raymond L. Toy , Ravinder D. Koilpillai
IPC分类号： H04L1/20 , H04L25/03 , H04J3/16 , H04J3/06
CPC分类号： H04L1/20 , H04L2025/0356 , H04L25/03178
摘要： A digital time division multiple access (TDMA) radio communications system employs a digital information source for providing digital information, a transmitter for transmitting encoded digital information in a radio-frequency (RF) signal to a receiver which demodulates the encoded symbols into digital information to be utilized by an output device. The receiver, synchronizes, compensates for frequency drift, samples and divides the samples into halfslots of samples. The halfslots are subdivided into subslots numbered from 1 to N, where N represents the last received subslot. Subslots 1 and N are demodulated into digital information in a forward and reverse direction, respectively with metrics calculated. If the metrics indicate a signal with a larger signal-to-noise ratio from subslot N, subslot N-1 is demodulated in a reverse sense with another reverse metric calculated, and vice versa. This process of extending demodulation in the direction of greater signal strength is repeated until all subslots in the slot have been demodulated. A second embodiment passes through all subslots in a forward and reverse direction calculating subslot metrics. The subslot metrics are summed into a halfslot metrics. The best halfslot metric indicates the sense of demodulation of each subslot. The digital information is then dumped in the proper order and sense to an output device which utilizes the digital information resulting in increased performance during fade periods.
摘要翻译：数字时分多址（TDMA）无线通信系统采用数字信息源提供数字信息，发射机用于将射频（RF）信号中的编码数字信息发射到接收机，该接收机将编码符号解调为数字信息，由输出设备使用。接收机同步，补偿频率漂移，采样并将样品分成样品半槽。半槽被细分为从1到N的子槽，其中N表示最后接收的子槽。分别将子空间1和N按正向和反向方向分别解调成数字信息。如果度量指示具有来自子时隙N的更大的信噪比的信号，则在具有反向意义上的子载波N-1中使用另一个反向度量计算解调，反之亦然。重复在更大的信号强度的方向上扩展解调的过程，直到时隙中的所有子时隙已被解调为止。第二实施例在向前和向后的方向上通过所有子时隙计算子时间度量。子时间度量被总计为半数指标。最佳半时隙度量表示每个子时隙的解调感。然后将数字信息以适当的顺序和感觉倾倒到使用数字信息的输出设备，从而在淡化时段期间提高性能。

7. 发明授权

US6134260A Method and apparatus for frequency acquisition and tracking for DS-SS CDMA receivers 失效
标题翻译：用于DS-SS CDMA接收机的频率采集和跟踪的方法和装置
公开(公告)号：US6134260A
公开(公告)日：2000-10-17
申请号：US991770
申请日：1997-12-16
申请人： Gregory E. Bottomley , Raymond L. Toy , Sandeep Chennakeshu , Karl J. Molnar
发明人： Gregory E. Bottomley , Raymond L. Toy , Sandeep Chennakeshu , Karl J. Molnar
IPC分类号： H04B1/7075 , H04B1/7085 , H04R15/00
CPC分类号： H04B1/7075 , H04B1/7085
摘要： Systems and methods for frequency acquisition and channel tracking in a direct sequence code division multiple access system are described. Frequency estimates are prepared and refined, which estimates are also used in the channel tracking process.
摘要翻译：描述了直接序列码分多址系统中频率采集和信道跟踪的系统和方法。频率估计被准备和改进，这些估计也用于信道跟踪过程。

8. 发明授权

US5349589A Generalized viterbi algorithm with tail-biting 失效
标题翻译：广义维特比算法带尾巴
公开(公告)号：US5349589A
公开(公告)日：1994-09-20
申请号：US724280
申请日：1991-07-01
申请人： Sandeep Chennakeshu , Raymond L. Toy
发明人： Sandeep Chennakeshu , Raymond L. Toy
IPC分类号： H03M13/35 , H03M13/41 , H04L1/00 , G06F11/10
CPC分类号： H04L1/0065 , H03M13/35 , H03M13/41 , H03M13/4115 , H03M13/4123 , H03M13/413 , H03M13/6502 , H04L1/0054 , H04L1/007
摘要： A method and apparatus for digital radio communication employs separation of a frame of data to be transmitted into key bits, critical bits and unprotected bits. The key bits are processed to provide parity bits. The parity bits, and key bits are convolutionally encoded using a tail-biting scheme and merged with unprotected bits, and then transmitted. At the receiver, the decoder splits the received data into convolutionally encoded bits and unprotected bits, and trellis decodes the convolutionally encoded bits into a number of possible paths through a trellis using a generalized Viterbi algorithm. The tail-biting scheme reduces the number of bits that must be transmitted. Paths having errors in the key bits are rejected, and the path having the best metric without key bit errors is used in decoding the transmitted information. In the event that there is no such path, a previously selected path is substituted and decoded.
摘要翻译：一种用于数字无线电通信的方法和装置通过将要发送的数据帧分离成密钥位，关键位和未受保护位。处理关键位以提供奇偶校验位。奇偶校验位和密钥位使用尾巴方案进行卷积编码，并与未受保护的位合并，然后发送。在接收机处，解码器将接收到的数据分解成卷积编码比特和无保护比特，并且使用广义维特比算法将卷积编码的比特格网解码成通过网格的多个可能路径。尾巴方案减少了必须传输的位数。在密钥比特中出现错误的路径被拒绝，并且在解码所发送的信息中使用具有没有密钥比特错误的最佳度量的路径。在没有这样的路径的情况下，先前选择的路径被替换和解码。

9. 发明授权

US5177740A Frame/slot synchronization for U.S. digital cellular TDMA radio telephone system 失效
标题翻译：美国数字蜂窝TDMA无线电话系统的帧/时隙同步
公开(公告)号：US5177740A
公开(公告)日：1993-01-05
申请号：US754108
申请日：1991-09-03
申请人： Raymond L. Toy , Sandeep Chennakeshu
发明人： Raymond L. Toy , Sandeep Chennakeshu
IPC分类号： H04B7/26 , H04L7/04 , H04L7/08
CPC分类号： H04W56/0085 , H04B7/2681 , H04L7/042 , H04L7/041 , H04L7/08
摘要： Frame/slot synchronization is applied to a received Time Division Multiple Access (TDMA) signal and a temporal position of a reference feature is acquired, such as a synchronizing bit stream or preamble, associated with a desired time slot. The desired time slot is but one of a plurality of time slots that comprise a frame. Verification that the acquired temporal position corresponds to the desired time slot is performed by repetitively estimating a temporal position of the reference feature in a subsequent frame and sampling the subsequent frame at the estimated temporal position to determine if the reference feature is present. The temporal position of the reference feature of the desired time slot relative to the frame is maintained over a plurality of received frames.
摘要翻译：帧/时隙同步被应用于接收的时分多址（TDMA）信号，并且获取参考特征的时间位置，诸如与期望时隙相关联的同步比特流或前同步码。期望的时隙是包括帧的多个时隙中的一个。通过重复地估计后续帧中的参考特征的时间位置并在估计的时间位置对后续帧进行采样来确定所获取的时间位置对应于所需时隙的确认，以确定参考特征是否存在。相对于帧的所需时隙的参考特征的时间位置在多个接收帧上保持。

10. 发明授权

US5968199A High performance error control decoder 失效
标题翻译：高性能错误控制解码器
公开(公告)号：US5968199A
公开(公告)日：1999-10-19
申请号：US768530
申请日：1996-12-18
申请人： Ali S. Khayrallah , Raymond L. Toy , Sandeep Chennakeshu
发明人： Ali S. Khayrallah , Raymond L. Toy , Sandeep Chennakeshu
IPC分类号： G10L19/00 , H03M13/00 , H03M13/03 , H03M13/15 , H03M13/37 , H03M13/39 , H03M13/43 , H03M13/45
CPC分类号： H03M13/45 , H03M13/00 , H03M13/1505 , H03M13/151 , H03M13/3738 , H03M13/616 , H03M13/618 , H03M13/6577 , H03M13/658 , G10L19/005
摘要： An error control decoder receives a received vector to be decoded. The decoder then calculates, as an error estimate, the Euclidean distance between a codeword choice and the received vector. The output error estimate is appropriately scaled and quantized in accordance with the particular code being processed by the decoder. The efficient Conway-Sloane algorithm is extended for use in connection with the decoding of shortened Golay codes. A modification is made to the generator matrix for the Golay code to produce a modified generator matrix that is unique for each shortened code. The modified generator matrix is then implemented in the Conway-Sloane algorithm to identify the best codeword for conversion to its corresponding information bits for output.
摘要翻译：误差控制解码器接收要被解码的接收矢量。解码器然后计算码字选择和接收向量之间的欧几里德距离作为误差估计。根据由解码器处理的特定代码适当地缩放和量化输出误差估计。有效的Conway-Sloane算法被扩展用于与缩短的Golay码的解码结合使用。对于Golay码的发生器矩阵进行修改以产生对于每个缩短的代码是唯一的修改的生成器矩阵。然后，以Conway-Sloane算法实现修改后的生成矩阵，以识别用于转换为其相应信息比特以输出的最佳码字。

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