专利快速检索-快速检索全球专利，免费商用专利数据库-IPRDB

41. 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。

42. 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。

43. 发明授权

US5353307A Automatic simulcast alignment 失效
标题翻译：自动联播对齐
公开(公告)号：US5353307A
公开(公告)日：1994-10-04
申请号：US95367
申请日：1993-07-20
申请人： Howard L. Lester , Sandeep Chennakeshu
发明人： Howard L. Lester , Sandeep Chennakeshu
IPC分类号： H04H20/67 , H04L7/02 , H04L25/03 , H03H7/30 , H03H7/40
CPC分类号： H04H20/67 , H04L25/03057 , H04L2025/03656
摘要： A digital simulcast transmission is automatically aligned, at a simulcast receiver (22) that simultaneously receives a plurality of RF signals from a plurality of transmitters, each of the RF signals being modulated to convey identical digitally encoded information. An equalizer (24) adaptively equalizes the plurality of received RF signals to substantially correct for a misalignment in time between the received signals. The misalignment in time is due in part to a non-simultaneous transmission of the identical digitally encoded information from the plurality of transmitters. Equalizer embodiments include a Decision Feedback Equalizer (DFE) and an equalizer based on a Maximum Likelihood Sequence Estimator (MLSE). Embodiments of the DFE are an Order Recursive Lattice-DFE and a Fast Kalman DFE.
摘要翻译：在同时从多个发射机接收多个RF信号的同时接收机（22），数字联播传输被自动对准，每个RF信号被调制以传送相同的数字编码信息。均衡器（24）自适应地均衡多个接收到的RF信号，以基本上校正接收信号之间的时间偏移。在时间上的偏移部分是由于来自多个发射机的相同数字编码信息的非同时传输。均衡器实施例包括基于最大似然序列估计器（MLSE）的判决反馈均衡器（DFE）和均衡器。 DFE的实施例是订单递归晶格-DFE和快速卡尔曼DFE。

44. 发明授权

US5202901A Digital discriminator for pulse shaped .pi./4 shifted differentially encoded quadrature phase shift keying 失效
标题翻译：用于脉冲形pi / 4移位差分编码正交相移键控的数字鉴频器
公开(公告)号：US5202901A
公开(公告)日：1993-04-13
申请号：US703517
申请日：1991-05-21
申请人： Sandeep Chennakeshu , Gary J. Saulnier
发明人： Sandeep Chennakeshu , Gary J. Saulnier
IPC分类号： H04L27/233
CPC分类号： H04L27/2338
摘要： A digital radio receiver for synchronization of radiowave transmissions for digital and analog FM signals in TDMA systems such as cellular telephones uses a tangent type discriminator that minimizes the bit error rate. The digital discriminator employs A/D converter circuit that samples a received intermediate frequency (IF) signal, a sorter circuit that produces a predetermined number of samples to be used in the decoding, a sample and phase adjustment circuit that allows for a carrier phase adjustment and sample timing adjustment, a divider circuit that eliminates the need for a conventional limiter by causing a ratio of amplitudes to be processed instead of absolute signal amplitudes, an inverse tangent circuit that creates a decoded phase angle from the ratio, a delay circuit and a summer circuit that create a differential signal, a modulo-2.pi. correction circuit that corrects for wrap-around errors about the real axis, an integrate and dump filter for summing up all phase angles pertaining to a single symbol, and a four-phase decoder circuit to decode the signal into a pair of bits. An adjustment circuit minimizes phase error between a reference sequence of symbols and the decoded symbols by simultaneously adjusting the sample timing and carrier phase adjustments. The digital discriminator also can decode conventional analog FM radio broadcasts by deactivating the IDF, the adjustment circuit, and SPA circuit, and bypassing the four-phase decoder.
摘要翻译：用于在诸如蜂窝电话的TDMA系统中用于数字和模拟FM信号的无线电波传输的同步的数字无线电接收机使用使误码率最小化的切线型鉴别器。数字鉴频器采用对接收到的中频（IF）信号进行采样的A / D转换电路，产生要在解码中使用的预定数量样本的分选器电路，允许载波相位调整的采样和相位调整电路和采样定时调整，分频器电路通过引起要被处理的幅度比而不是绝对信号幅度来消除对常规限幅器的需要，从该比值产生解码相位角的反正切电路，延迟电路和创建差分信号的夏季电路，用于校正关于实轴的环绕误差的模2π校正电路，用于对与单个符号相关的所有相位角进行求和的积分和转储滤波器以及四相解码器电路将信号解码成一对位。调整电路通过同时调整采样定时和载波相位调整来最小化参考符号序列和解码符号之间的相位误差。数字鉴频器还可以通过去激活IDF，调节电路和SPA电路以及绕过四相解码器来解码传统的模拟FM无线电广播。

45. 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。

46. 发明授权

US07269846B2 Mobile terminal having virus resistant security module architecture 有权
标题翻译：具有防病毒安全模块架构的移动终端
公开(公告)号：US07269846B2
公开(公告)日：2007-09-11
申请号：US10231958
申请日：2002-08-30
申请人： Sandeep Chennakeshu , William O. Camp, Jr.
发明人： Sandeep Chennakeshu , William O. Camp, Jr.
IPC分类号： G06F17/00 , G06F7/04 , H04L12/58
CPC分类号： H04W88/02 , H04L63/083 , H04L63/0861 , H04W12/06 , H04W12/08 , H04W12/12
摘要： Mobile terminal having virus resistant security module architecture. An embedded security module can control the presentation of information on a display by controlling access to display memory. In some embodiments, the security module is also provided with an interface to enable it to handle user input function as well. In this way, the presentation of transaction information and receipt of user input can be substantially isolated from the main, control microprocessor of the terminal for enhanced security, especially protection against resident viruses. In addition, the security module can copy display data into the authentication and/or authorization message that is returned by the terminal to the base station. The return of the display data provides an extra, secure confirmation of the transaction.
摘要翻译：具有防病毒安全模块架构的移动终端。嵌入式安全模块可以通过控制显示存储器的访问来控制显示器上的信息显示。在一些实施例中，安全模块还提供有使其能够处理用户输入功能的接口。以这种方式，交易信息的呈现和用户输入的接收可以与终端的主控制微处理器基本上隔离，以增强安全性，特别是针对常驻病毒的保护。此外，安全模块可以将显示数据复制到由终端返回给基站的认证和/或授权消息中。显示数据的返回为交易提供了额外的安全确认。

47. 发明授权

US06535547B1 Random access in a mobile telecommunications system 有权
标题翻译：移动电信系统中的随机接入
公开(公告)号：US06535547B1
公开(公告)日：2003-03-18
申请号：US09324372
申请日：1999-06-02
申请人： Bo Lyckegård , Riaz Esmailzadeh , Johan Nyström , Erik Dahlman , Sandeep Chennakeshu , Karim Jamal
发明人： Bo Lyckegård , Riaz Esmailzadeh , Johan Nyström , Erik Dahlman , Sandeep Chennakeshu , Karim Jamal
IPC分类号： H04L2730
CPC分类号： H04W74/004 , H04J13/004 , H04W74/0833
摘要： A method for improving the performance of a random access communications system in a variable radio environment is disclosed, whereby at least one valid set of burst signatures is used for transmission by one or more mobile stations. Each set includes at least one signature with a different signature-length than the signatures in other sets. The different signature-lengths can be optimized for the operational environments involved (e.g., longer signatures for slower-moving mobile stations, and shorter signatures for high-speed mobile stations). Alternatively, at least one differentially-encoded signature is used for random access transmissions, in order to reduce the radio channel's sensitivity to large doppler spreads and frequency errors.
摘要翻译：公开了一种用于在可变无线电环境中改善随机接入通信系统的性能的方法，由此至少一个有效的突发特征集合被一个或多个移动台用于传输。每个集合包括与其他集合中的签名不同的签名长度的至少一个签名。不同的签名长度可以针对所涉及的操作环境进行优化（例如，较慢移动的移动站的签名较长，以及用于高速移动站的较短的签名）。或者，至少一个差分编码的签名用于随机接入传输，以便减少无线电信道对大多普勒扩展和频率误差的敏感性。

48. 发明授权

US06415154B1 METHOD AND APPARATUS FOR COMMUNICATING AUXILLIARY INFORMATION AND LOCATION INFORMATION BETWEEN A CELLULAR TELEPHONE NETWORK AND A GLOBAL POSITIONING SYSTEM RECEIVER FOR REDUCING CODE SHIFT SEARCH TIME OF THE RECEIVER 有权
标题翻译：用于通信蜂窝电话网络和全球定位系统接收器之间的辅助信息和位置信息的方法和装置，用于减少代码移位接收器的搜索时间
公开(公告)号：US06415154B1
公开(公告)日：2002-07-02
申请号：US09167077
申请日：1998-10-06
申请人： Yi-Pin Eric Wang , Sandeep Chennakeshu
发明人： Yi-Pin Eric Wang , Sandeep Chennakeshu
IPC分类号： H04Q720
CPC分类号： G01S5/0036 , G01S19/25 , G01S19/37 , G01S2205/008
摘要： A method and apparatus for communicating auxiliary information between a cellular telephone network and a GPS receiver positioned within a mobile station and identifying the location of the mobile station. A dedicated channel between the mobile station and the network is assigned by the network and uplink timing between the mobile station and the network is adjusted. The network requests auxiliary information and also requests the GPS receiver to perform a GPS code shift search at a common reference time. Upon receiving the auxiliary information, the network transmits the auxiliary information to the GPS receiver which then performs the GPS code shift search. The GPS receiver incorporates a bank of correlators and accumulators to perform multiple parallel searches for various Doppler frequency shifts resulting from a moving GPS receiver. The mobile station subsequently transmits the location information to the cellular telephone network.
摘要翻译：一种用于在蜂窝电话网络和位于移动站内的GPS接收机之间传送辅助信息并识别移动台的位置的方法和装置。通过网络分配移动台与网络之间的专用信道，调整移动台与网络之间的上行定时。网络请求辅助信息，并请求GPS接收机在公共参考时间执行GPS码移动搜索。在接收到辅助信息时，网络将辅助信息发送到GPS接收机，然后执行GPS码移动搜索。 GPS接收机包含一组相关器和累加器，以对移动的GPS接收机产生的各种多普勒频移进行多次并行搜索。移动台随后将位置信息发送到蜂窝电话网络。

49. 发明授权

US06314081B1 High power short message service using dedicated carrier frequency 失效
标题翻译：使用专用载波频率的大功率短信业务
公开(公告)号：US06314081B1
公开(公告)日：2001-11-06
申请号：US08588507
申请日：1996-01-18
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： H04J1100
CPC分类号： H04W4/14 , H04B7/18567
摘要： A communication system and method for transmitting relatively short data messages in the communication system. A dedicated frequency is sequentially switched into each of a plurality of satellite beams or traffic channels to transmit data messages at an increased power level to provide an increased signal margin. The increased power level of the dedicated frequency can be combined with coding and bit and message repetition to further increase the signal margin.
摘要翻译：一种用于在通信系统中发送相对短的数据消息的通信系统和方法。专用频率被顺序地切换到多个卫星波束或业务信道中的每一个以在增加的功率电平上发送数据消息以提供增加的信号余量。专用频率的增加的功率电平可以与编码和比特和消息重复组合以进一步增加信号余量。

50. 发明授权

US06192503B1 Communications system and methods employing selective recursive decording 失效
标题翻译：通信系统和方法采用选择性递归解码
公开(公告)号：US06192503B1
公开(公告)日：2001-02-20
申请号：US08911149
申请日：1997-08-14
申请人： Sandeep Chennakeshu , Amer A. Hassan
发明人： Sandeep Chennakeshu , Amer A. Hassan
IPC分类号： H03M1303
CPC分类号： H04L1/005 , H03M13/2975 , H04L1/0055 , H04L1/0066 , H04L1/007
摘要： A source sequence of symbols is communicated over a communications medium by encoding the source sequence according to respective first and second error correction codes to produce respective first and second encoded sequences of symbols. The first and second encoded sequences are processed to produce a communications signal, which is then communicated over the communications medium. The communicated communications signal is processed to produce first and second received sequences of symbols corresponding to the first and second encoded sequences, respectively. The first and second received sequences are selectively recursively decoded according to the associated error correction codes augmented by previous estimates of a symbol of the source sequence to repeatedly produce revised estimates of the symbol until an estimate satisfying a predetermined reliability criteria is obtained.
摘要翻译：通过在源通信介质上通过根据相应的第一和第二纠错码对源序列进行编码来传送符号的源序列，以产生相应的第一和第二编码符号序列。处理第一和第二编码序列以产生通信信号，然后通信信号在通信介质上传送。所传送的通信信号被处理以分别产生对应于第一和第二编码序列的第一和第二接收的符号序列。根据由源序列的符号的先前估计增加的相关联的纠错码来选择性地递归地解码第一和第二接收序列，以重复产生符号的修正估计，直到获得满足预定可靠性标准的估计。

你已经成功收藏专利！

检索式保存成功!

IPRDB

热门服务

关于我们

友情链接

联系方式