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1.发明授权Protocol and mechanism for primary and mutter mode communication for asset tracking 失效用于资产跟踪的主要和嘟嘟模式通信的协议和机制
公开(公告)号：US5588005A
公开(公告)日：1996-12-24
申请号：US487272
申请日：1995-06-07
申请人： Irfan Ali , John E. Hershey , Stephen M. Hladik , Amer A. Hassan , Sandeep Channakeshu , Ravinder D. Koilpillai , Kenneth B. Welles, II , Harold W. Tomlinson
发明人： Irfan Ali , John E. Hershey , Stephen M. Hladik , Amer A. Hassan , Sandeep Channakeshu , Ravinder D. Koilpillai , Kenneth B. Welles, II , Harold W. Tomlinson
IPC分类号： G01C21/00 , B61L25/02 , G01S5/00 , G01S5/14 , G01S19/42 , G08B25/04 , G08G1/127 , H04B7/185 , H04B7/212 , H04L12/28 , H04L12/56 , H04Q7/00
CPC分类号： H04W84/12 , B61L25/021 , B61L25/025 , G01S5/0027 , G08G1/127 , H04B7/18545 , H04B7/18576 , H04W84/20 , B61L2205/04 , G01S19/09 , G01S19/14 , H04W8/02 , Y02B60/50
摘要： A mode of communication for asset tracking units involves communication between a central station and the individual tracking units, usually through a satellite link. This mode is the primary communication link for tracking the assets. A second mode is the local area network (LAN) or "mutter" mode, in which a subset of tracking units communicate with each other in a mobile LAN. This mode is used as the secondary communication mechanism to conserve power, since mutter mode communication requires much less energy for local communication between the tracking units as opposed to direct satellite communication with the central station. In addition, mutter mode leads to increased reliability of the asset tracking system by enabling tracking of units which have batteries too weak to support communication with the central station, but strong enough to support communication in mutter mode. The mutter mode is also useful in finding tracking units which are not communicating with the central station due primary communication equipment fault or other inhibiting condition.
摘要翻译： 用于资产跟踪单元的通信模式涉及通常通过卫星链路在中心站和各个跟踪单元之间的通信。 此模式是用于跟踪资产的主要通信链接。 第二模式是局域网（LAN）或“嘟嘟”模式，其中跟踪单元的子集在移动LAN中彼此通信。 该模式用作次要通信机制以节省功率，因为对于与中心站的直接卫星通信相反，跟踪单元之间的本地通信需要更少的能量。 此外，嘟嘟模式通过对具有电池太弱的单元进行跟踪以支持与中心站的通信，从而提高资产跟踪系统的可靠性，但足够强大以支持在嘟嘟模式下的通信。 由于主要通信设备故障或其他抑制条件，嘟嘟模式也可用于找到不与中心站通信的跟踪单元。
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2.发明授权Adaptive phase-locked loop employing channel state information estimation from received signal phase angles 失效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
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。
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3.发明授权
公开(公告)号：US5774799A
公开(公告)日：1998-06-30
申请号：US634229
申请日：1996-04-18
CPC分类号： H03J7/04 , H03J1/0008
摘要： A robust automatic frequency control (AFC) loop for use in radio frequency systems performs a threshold test on the accumulated error adjustments for controlling a frequency oscillator. Based on this test, the loop adjusts the value contained in the error accumulator to allow the receiver to remain locked to a desired frequency carrier even in the presence of a strong adjacent channel interferer. The AFC loop is designed to be used in error systems where the predetermined fixed carrier spacing. Assuming that the initial frequency error is never exceeded by one-half the carrier spacing, the system can determine if the wrong channel has been locked to if the oscillator in the AFC loop is corrected by more than half the carrier spacing. Through use of a threshold test on the accumulative oscillator correction, the AFC loop can determine if the receiver has locked to an adjacent interfering channel. Having determined such a lock has occurred, the oscillator can be adjusted by plus or minus one channel, thus reestablishing connection of the AFC loop to the desired channel.
摘要翻译： 用于射频系统的强大的自动频率控制（AFC）回路对累积的误差调整进行阈值测试，以控制频率振荡器。 基于该测试，该循环调整包含在误差累加器中的值，以允许接收机即使在存在强相邻信道干扰源的情况下也保持锁定到期望的频率载波。 AFC循环设计用于在预定的固定载波间隔的误差系统中。 假设初始频率误差不会超过载波间隔的一半，如果AFC环路中的振荡器校正了载波间隔的一半以上，则系统可以确定错误的信道是否被锁定。 通过对累积振荡器校正使用阈值测试，AFC循环可以确定接收机是否锁定到相邻的干扰信道。 已经确定了这种锁定后，振荡器可以通过加或减一个通道进行调整，从而重新建立AFC回路与所需通道的连接。
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4.发明授权Low complexity adaptive equalizer radio receiver employing reduced complexity branch metric calculation 失效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
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。
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5.发明授权Low complexity adaptive equalizer radio receiver employing direct reference state updates 失效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
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。
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6.发明授权Sample timing selection and frequency offset correction for U.S. digital cellular mobile receivers 失效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
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。
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7.发明授权
公开(公告)号：US5870406A
公开(公告)日：1999-02-09
申请号：US803184
申请日：1997-02-19
CPC分类号： H04L1/1845 , H04L1/1803 , H04L1/188
摘要： If no uncorrectable errors are discovered in a received data packet, an acknowledgment is sent back to the sender. Conversely, if the data packet contains uncorrectable errors, no acknowledgment is sent, forcing a re-transmission of that data packet in accordance with an automatic repeat request (ARQ) procedure. In such cases, sets of unquantized signal values relating to received data packets having uncorrectable errors are stored. When two or more sets of unquantized signal values for the same received data packet (as re-transmitted) have been stored, the unquantized signal values are numerically combined on a bit-by-bit basis, and then quantized to regenerate a combined data packet. If no uncorrectable errors are discovered in that combined data packet, an acknowledgment is sent back to the sender. Otherwise, no acknowledgment is sent, forcing another data packet re-transmission.
摘要翻译： 如果在接收到的数据包中没有发现不可纠正的错误，则将确认发送回发送方。 相反，如果数据分组包含不可校正的错误，则不发送确认，强制根据自动重复请求（ARQ）过程重传该数据分组。 在这种情况下，存储与具有不可校正错误的接收数据分组有关的未量化信号值集合。 当已经存储了相同的接收数据分组（如重新发送）的两组或更多组未量化的信号值时，未量化的信号值被逐个数字地组合，然后被量化以再生组合的数据分组 。 如果在该组合数据分组中没有发现不可校正的错误，则将确认发送回发送方。 否则，不发送确认，强制另一个数据包重传。
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8.发明授权Low complexity adaptive equalizer for U.S. digital cellular radio receivers 失效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
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。
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9.发明授权Double sided slot traversing decoding for time division multiple access (TDMA) radio systems 失效用于时分多址（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
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。
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