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1. 发明授权

US5909465A Method and apparatus for bidirectional demodulation of digitally modulated signals 失效
标题翻译：用于数字调制信号的双向解调的方法和装置
公开(公告)号：US5909465A
公开(公告)日：1999-06-01
申请号：US761003
申请日：1996-12-05
申请人： Gregory Edward Bottomley , Paul Wilkinson Dent , Ravinder David Koilpillai , Sandeep Chennakeshu
发明人： Gregory Edward Bottomley , Paul Wilkinson Dent , Ravinder David Koilpillai , Sandeep Chennakeshu
IPC分类号： H03M13/37 , H04B7/005 , H04B7/26 , H04L25/03 , H04L25/49 , H04Q1/20 , H04B17/00
CPC分类号： H04L25/03178 , H04L2025/0356
摘要： A system and method for bidirectionally demodulating data symbols transmitted through a communication channel. The method includes sequentially receiving and storing a first plurality of known data symbols, a second plurality of unknown data symbols, and a third plurality of known data symbols. Thereafter, a first block of the unknown data symbols received nearer the first plurality of known data symbols is forward-demodulated. Likewise, a second block of the unknown data symbols received nearer the third plurality of known data symbols is backward-demodulated. The forward- and backward-demodulation of the unknown data symbols determines quality values (figure-of-merits based on at least one of signal power, noise power and a combination of signal power plus noise power) indicative of demodulation qualities of the unknown data symbols that are compared to produce a best direction indication. Upon determining the best direction indication, either the forward- or backward-demodulation steps are repeated for subsequent blocks of unknown data symbols.
摘要翻译：一种用于双向解调通过通信信道发送的数据符号的系统和方法。该方法包括顺序地接收和存储第一多个已知数据符号，第二多个未知数据符号和第三多个已知数据符号。此后，向第一多个已知数据符号接收的未知数据符号的第一块进行前向解调。类似地，接收到的接近第三多个已知数据符号的未知数据符号的第二块被反向解调。未知数据符号的前向和后向解调确定指示未知数据的解调质量的质量值（基于信号功率，噪声功率和信号功率加噪声功率的组合中的至少一个）的品质值比较符号以产生最佳方向指示。在确定最佳方向指示时，对于未知数据符号的后续块重复前向或后向解调步骤。

2. 发明授权

US5991331A System for improving the quality of a received radio signal 失效
标题翻译：提高接收无线电信号质量的系统
公开(公告)号：US5991331A
公开(公告)日：1999-11-23
申请号：US978911
申请日：1997-11-26
申请人： Sandeep Chennakeshu , Gregory Edward Bottomley , Paul Wilkinson Dent
发明人： Sandeep Chennakeshu , Gregory Edward Bottomley , Paul Wilkinson Dent
IPC分类号： H04B1/12 , H04B1/713 , H04B1/715 , H04B7/04 , H04B7/06 , H04B7/08 , H04B7/12 , H04J3/00 , H04K1/00
CPC分类号： H04B7/0894 , H04B1/713 , H04B1/715 , H04B7/0671 , H04B7/084 , H04B1/126
摘要： A delay spread is created in a digital radio signal to reduce the coherence bandwidth and facilitate frequency hopping to reduce the effect of fading losses within an enclosed propagation environment. The delay spread is introduced into the signal in several ways. One technique disclosed employs a transmitter with two separate antennas one of which transmits the digital signal and the other of which transmits the same signal after a phase delay has been introduced into the signal. The carrier frequency of the signals is hopped between at least two frequencies and the receiver processes the resulting signals. In another embodiment, a single transmit antenna is used but the signal is received by two different antennas with the output signal from one of those antennas being phase delayed before combining it with the other prior to processing by the receiver circuitry. Phase delay is also introduced at baseband into the signals to be transmitted by rotating the I and Q components of the waveforms before modulation.
摘要翻译：在数字无线电信号中产生延迟扩展以减少相干带宽并促进跳频以减少封闭传播环境内的衰落损耗的影响。延迟传播以几种方式被引入到信号中。所公开的一种技术采用具有两个单独天线的发射机，其中一个发射数字信号，而另一个天线在相位延迟被引入信号之后发射相同的信号。信号的载波频率在至少两个频率之间跳跃，并且接收机处理所得到的信号。在另一个实施例中，使用单个发射天线，但是信号由两个不同的天线接收，其中一个天线的输出信号在被接收机电路处理之前与另一天线组合之前被相位延迟。在调制之前，通过旋转波形的I和Q分量，在基带处将相位延迟也引入要发送的信号。

3. 发明授权

US6034987A System for improving the quality of a received radio signal 失效
标题翻译：提高接收无线电信号质量的系统
公开(公告)号：US6034987A
公开(公告)日：2000-03-07
申请号：US768319
申请日：1996-12-17
申请人： Sandeep Chennakeshu , Gregory Edward Bottomley , Paul Wilkinson Dent
发明人： Sandeep Chennakeshu , Gregory Edward Bottomley , Paul Wilkinson Dent
IPC分类号： H04B1/12 , H04B1/713 , H04B1/715 , H04B7/04 , H04B7/06 , H04B7/08 , H04B7/12 , H04J3/00 , H04K1/10
CPC分类号： H04B7/0894 , H04B1/713 , H04B1/715 , H04B7/0671 , H04B7/084 , H04B1/126
摘要： A delay spread is created in a digital radio signal to reduce the coherence bandwidth and facilitate frequency hopping to reduce the effect of fading losses within an enclosed propagation environment The delay spread is introduced into the signal in several ways. One technique disclosed employs a transmitter with two separate antennas one of which transmits the digital signal and the other of which transmits the same signal after a phase delay has been introduced into the signal. The carrier frequency of the signals is hopped between at least two frequencies and the receiver processes the resulting signals. In another embodiment, a single transmit antenna is used but the signal is received by two different antennas with the output signal from one of those antennas being phase delayed before combining it with the other prior to processing by the receiver circuitry. Phase delay is also introduced at baseband into the signals to be transmitted by rotating the I and Q components of the waveforms before modulation.
摘要翻译：在数字无线电信号中产生延迟扩展以减少相干带宽并促进跳频以减少封闭传播环境内的衰落损耗的影响。延迟扩展以几种方式被引入到信号中。所公开的一种技术采用具有两个单独天线的发射机，其中一个发射数字信号，而另一个天线在相位延迟被引入信号之后发射相同的信号。信号的载波频率在至少两个频率之间跳跃，并且接收机处理所得到的信号。在另一个实施例中，使用单个发射天线，但是信号由两个不同的天线接收，其中一个天线的输出信号在被接收机电路处理之前与另一天线组合之前被相位延迟。在调制之前，通过旋转波形的I和Q分量，在基带处将相位延迟也引入要发送的信号。

4. 发明授权

US6031874A Unequal error protection in coded modulation schemes 失效
标题翻译：编码调制方案中的不正确的错误保护
公开(公告)号：US6031874A
公开(公告)日：2000-02-29
申请号：US938516
申请日：1997-09-26
申请人： Sandeep Chennakeshu , Ravinder David Koilpillai
发明人： Sandeep Chennakeshu , Ravinder David Koilpillai
IPC分类号： H04L1/00 , H04L23/02
CPC分类号： H04L1/0058 , H04L1/0041 , H04L1/007
摘要： An important consideration in a coded modulation scheme is the choice of the component codes, which has a significant impact on the overall bit error rate performance and which determines the decoding complexity. Methods and apparatus employing product codes are described that can improve the performance of selected classes of information in the coded modulation scheme without affecting the decoding complexity or performance of other classes of information.
摘要翻译：编码调制方案中的一个重要考虑因素是组件代码的选择，其对整体误码率性能具有显着影响，并且决定了解码的复杂性。描述了使用产品代码的方法和装置，其可以改进编码调制方案中所选类别的信息的性能，而不影响其他类别的信息的解码复杂度或性能。

5. 发明授权

US06327317B1 Combined equalization and decoding techniques 有权
标题翻译：组合均衡和解码技术
公开(公告)号：US06327317B1
公开(公告)日：2001-12-04
申请号：US09393881
申请日：1999-09-10
申请人： Sandeep Chennakeshu , Ravinder David Koilpillai
发明人： Sandeep Chennakeshu , Ravinder David Koilpillai
IPC分类号： H03D100
CPC分类号： H04L1/0057 , H04L25/03019 , H04L25/03178 , H04L25/03184
摘要： Combined equalization and decoding of codewords in a coded modulation symbol sequence that has been received from a channel is accomplished in a number of ways. In an intersymbol interference (ISI) cancellation technique, channel impulse response (CIR) estimates corresponding to each received symbol of the coded modulation symbol sequence are determined. Codeword k of the received symbol sequence is then decoded using a maximum likelihood decoding trellis with a path metric that depends upon the CIR estimates and that includes at least one term representing intersymbol interference resulting from symbols of previously decoded codewords. The decoding step is repeated until all of the codewords of the received coded modulation symbol sequence have been decoded. In a maximum likelihood sequence estimation (MLSE)-based technique, an MLSE trellis is advanced from one stage to a next stage by updating a path metric having dependence on the CIR estimates and upon symbols of a codeword corresponding to a state in a previous trellis stage. The trellis-advancing step is repeated until all stages of the MLSE trellis are completed. Then, the codewords are decoded by using a traceback along the best path in the completed MLSE trellis. In another embodiment, a hybrid MLSE-ISI technique utilizes a path metric that depends upon the CIR estimates and upon symbols of a codeword corresponding to a state in a previous trellis stage. The path metric further includes at least one term that represents intersymbol interference resulting from symbols of previously decoded codewords.
摘要翻译：已经以多种方式实现了从信道接收到的编码调制符号序列中码字的组合均衡和解码。在符号间干扰（ISI）消除技术中，确定与编码调制符号序列的每个接收符号对应的信道脉冲响应（CIR）估计。然后使用具有取决于CIR估计的路径度量的最大似然解码网格对接收到的符号序列的码字k进行解码，并且包括至少一个表示由先前解码的码字的符号产生的符号间干扰的项。重复解码步骤，直到所接收的编码调制符号序列的所有码字已被解码。在基于最大似然序列估计（MLSE）的技术中，通过更新具有对CIR估计的依赖性的路径度量以及对应于先前网格中的状态的码字的符号，MLSE网格从一个阶段进入下一个阶段阶段。重新进行网格推进步骤，直到MLSE网格的所有阶段完成。然后，通过使用在完成的MLSE网格中的最佳路径的回溯来对码字进行解码。在另一个实施例中，混合MLSE-ISI技术利用取决于CIR估计的路径度量，以及对应于先前网格级中的状态的码字的符号。路径度量还包括至少一个术语，其表示由先前解码的码字的符号产生的符号间干扰。

6. 发明授权

US5905742A Method and apparauts for symbol decoding 失效
标题翻译：方法和符号解码
公开(公告)号：US5905742A
公开(公告)日：1999-05-18
申请号：US579349
申请日：1995-12-27
申请人： Sandeep Chennakeshu , Ravinder David Koilpillai , John B. Anderson
发明人： Sandeep Chennakeshu , Ravinder David Koilpillai , John B. Anderson
IPC分类号： H03M13/23 , H03M13/41 , H04L1/00 , H04L25/03 , G06F11/10
CPC分类号： H04L1/0071 , H03M13/41 , H03M13/6502 , H04L1/0009 , H04L25/03216
摘要： A low complexity, high performance trellis decoder adapts the complexity of the trellis decoding process based on a current condition of the communications system. A trellis structure of nodes and branches is developed to decode the sequence of symbols received over a communications channel. Each set of nodes in the trellis represents the possible values of a received symbol at one time instant. Each branch defines a specific transition between nodes at different time instants, and each branch has an associated branch metric or weight. A linkage of branches between the nodes and the trellis defines a path through the trellis that represents one possible symbol sequence, and an accumulated metric/weight is generated for each possible path through the trellis. A variable number M survivor paths through the trellis is determined based on their accumulated path metric/weights. The value of the variable M depends on the current condition of the communications system. Once the value of M is adapted to the current condition, the sequence of received symbols is decoded using M survivor paths through the trellis.
摘要翻译：低复杂度的高性能网格解码器基于通信系统的当前状况来适应网格解码过程的复杂性。开发节点和分支的网格结构来解码通过通信信道接收的符号序列。网格中的每组节点在一个时刻表示接收到的符号的可能值。每个分支定义不同时刻的节点之间的特定转换，并且每个分支具有关联的分支度量或权重。节点和网格之间的分支的链接定义了通过网格的路径，其表示一个可能的符号序列，并且通过网格为每个可能的路径生成累积的度量/权重。根据其累积的路径度量/权重来确定通过网格的可变数M个幸存者路径。变量M的值取决于通信系统的当前状态。一旦M的值适合于当前条件，则使用经过网格的M个幸存路径来解码接收符号的序列。

7. 发明授权

US06335954B1 Method and apparatus for joint synchronization of multiple receive channels 失效
标题翻译：用于多个接收信道的联合同步的方法和装置
公开(公告)号：US06335954B1
公开(公告)日：2002-01-01
申请号：US08773560
申请日：1996-12-27
申请人： Gregory Edward Bottomley , Sandeep Chennakeshu
发明人： Gregory Edward Bottomley , Sandeep Chennakeshu
IPC分类号： H04L700
CPC分类号： H04B7/0845
摘要： An apparatus for joint synchronization of digital communication signals from multiple receive channels comprises a control unit, a metric computer, and a decimator. The control unit generates test sampling phase vectors for use in decimating the signals. The output of the decimator is used by the metric computer to form a metric predictive of the performance of a demodulator. The metric is used by the control unit to select an optimal sampling phase vector. In one embodiment, the metric computer calculates the signal to impairment plus noise ratio (SINR) at the output of the demodulator based on the decimated signals. In one embodiment, a data correlation estimator generates a data correlation estimate for use in calculating output SINR. In another embodiment, the apparatus includes a select unit and a metric computer. The select unit may include a control unit and a decimator. The metric computer also includes at least one decimator. Test sampling phase vectors are provided to the metric computer along with the input signals. The metric computer generates a metric predictive of the performance of the interference canceling processor. The control unit selects a test sampling phase vector that optimizes performance of the interference canceling processor. The decimator decimates the input signals according to the sampling phases of the selected sampling phase vector. A method of joint synchronization of signals from multiple receive channels is also disclosed.
摘要翻译：用于来自多个接收信道的数字通信信号的联合同步的装置包括控制单元，度量计算机和抽取器。控制单元生成用于抽取信号的测试采样相位矢量。抽取器的输出由度量计算机使用以形成对解调器的性能的度量。控制单元使用度量来选择最佳采样相位矢量。在一个实施例中，度量计算机基于抽取的信号计算在解调器的输出处的损害加噪声比（SINR）的信号。在一个实施例中，数据相关估计器产生用于计算输出SINR的数据相关估计。在另一实施例中，该装置包括选择单元和度量计算机。选择单元可以包括控制单元和抽取器。公制计算机还包括至少一个抽取器。测量采样相位矢量与输入信号一起提供给公制计算机。度量计算机产生预测干扰消除处理器的性能的度量。控制单元选择优化干扰消除处理器的性能的测试采样相位矢量。抽取器根据所选采样相位矢量的采样相位对输入信号进行抽取。还公开了来自多个接收信道的信号的联合同步的方法。

8. 发明授权

US06212368B1 Measurement techniques for diversity and inter-frequency mobile assisted handoff (MAHO) 失效
标题翻译：用于分集和频间移动辅助切换（MAHO）的测量技术
公开(公告)号：US06212368B1
公开(公告)日：2001-04-03
申请号：US09085528
申请日：1998-05-27
申请人： Rajaram Ramesh , Sandeep Chennakeshu , Gregory E. Bottomley
发明人： Rajaram Ramesh , Sandeep Chennakeshu , Gregory E. Bottomley
IPC分类号： H04B1700
CPC分类号： H04W88/02 , H04B7/0808 , H04W24/10 , H04W36/06
摘要： Diversity and inter-frequency mobile-assisted handoff (MAHO) are achieved under continuous reception cellular access methods by using strategic timing and switching optimizations. Strategic timing is achieved by avoiding the non-reception of power control bits. For example, the mobile terminal can make measurements for diversity in the last eight bits of a sub-frame of an IS-95 downlink transmission. Switching is optimized, for example, by storing rake taps for a first antenna prior to switching to a second antenna so that the rake tap positions can be restored upon returning to the first antenna. With these and other disclosed measurement techniques, the benefits of diversity and inter-frequency MAHO can be achieved in continuous reception cellular systems.
摘要翻译：通过使用战略定时和切换优化，在连续接收蜂窝接入方式下实现分集和频间移动辅助切换（MAHO）。通过避免电源控制位的不接收来实现战略时序。例如，移动终端可以对IS-95下行链路传输的子帧的最后8位中的分集进行测量。优化切换，例如，在切换到第二天线之前，通过存储用于第一天线的雷击抽头，使得在返回到第一天线时可以恢复前叉抽头位置。利用这些和其他公开的测量技术，可以在连续接收蜂窝系统中实现分集和频间MAHO的益处。

9. 发明授权

US6085103A Compensating for fading in analog AM radio signals 失效
标题翻译：补偿模拟AM无线电信号中的衰落
公开(公告)号：US6085103A
公开(公告)日：2000-07-04
申请号：US802670
申请日：1997-02-19
申请人： Rajaram Ramesh , Sandeep Chennakeshu
发明人： Rajaram Ramesh , Sandeep Chennakeshu
IPC分类号： H04L9/30 , H04B7/005 , H04L9/36 , H04B15/00
CPC分类号： H04B7/005
摘要： A fading compensation apparatus and method are provided in which blocks of the analog AM signal (e.g., voice) are time-compressed at a transmitter. Gaps in the time-compressed signal are filled with pilot symbols (or similar complex waveforms) having known characteristics, such as predetermined amplitudes. The time-compressed analog AM signal (e.g., SSB or VSB) is transmitted over the fading channel. At an analog AM receiver, an estimate of the fading that occurred in the transmission channel is made by observing the amplitude of the received pilot symbols at discrete points in time, and interpolating to determine the amount of fading that occurred across the total transmitted signal. A fading compensator compares the received faded time-compressed signal with the interpolation results, and adjusts the amplitude and phase of the received signal accordingly to compensate for the fading that occurred in the transmission channel. The compensated analog AM signal is time expanded and output to a user.
摘要翻译：提供了一种衰落补偿装置和方法，其中模拟AM信号（例如，语音）的块在发射机处被时间压缩。用时间压缩信号的间隙填充具有已知特性（例如预定幅度）的导频符号（或类似的复杂波形）。时间压缩的模拟AM信号（例如，SSB或VSB）在衰落信道上传输。在模拟AM接收机处，通过在离散时间点观察接收到的导频符号的幅度来进行在传输信道中发生的衰落的估计，并进行内插以确定跨总传输信号发生的衰落量。衰落补偿器将接收到的衰落时间压缩信号与插值结果进行比较，并相应地调整接收信号的幅度和相位，以补偿在传输信道中发生的衰落。经补偿的模拟AM信号被时间扩展并输出给用户。

10. 发明授权

US6046990A High-penetration transmission method for a radiocommunication system 失效
标题翻译：用于无线电通信系统的高穿透传输方法
公开(公告)号：US6046990A
公开(公告)日：2000-04-04
申请号：US559692
申请日：1995-11-15
申请人： Sandeep Chennakeshu , Nils Rydbeck , Amer A. Hassan , Paul W. Dent
发明人： Sandeep Chennakeshu , Nils Rydbeck , Amer A. Hassan , Paul W. Dent
IPC分类号： H04B7/185 , H04L1/08 , H04W68/00 , H04W68/02 , H04W88/18 , H04B7/212
CPC分类号： H04L1/08 , H04B7/18567 , H04W68/00 , H04W68/02 , H04W88/185
摘要： A method and system for increasing the signal margin of a radiocommunication link to provide a short message service which is reliable, even under non-ideal conditions. According to the method, an increase in transmission power is used in combination with bit repetition to increase signal margin without complications in the mobile unit design, significant delay, or co-channel interference. Where a more significant increase in signal margin is desired, when a longer message is required, or for voice messages, the message may be stored and the mobile unit alerted of the message.
摘要翻译：一种用于增加无线电通信链路的信号余量以提供即使在非理想条件下也是可靠的短消息服务的方法和系统。根据该方法，与比特重复结合使用传输功率的增加以增加信号容限，而不会在移动单元设计，显着的延迟或同信道干扰中出现并发症。在需要更大幅度地增加信号余量的情况下，当需要更长的消息或者对于语音消息时，可以存储消息并且移动单元提醒消息。

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