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1. 发明授权

US07020072B1 Orthogonal frequency division multiplexing transmit diversity system for frequency-selective fading channels 有权
标题翻译：用于频率选择性衰落信道的正交频分复用发射分集系统
公开(公告)号：US07020072B1
公开(公告)日：2006-03-28
申请号：US09568170
申请日：2000-05-09
申请人： Xiaodong Li , Constantinos Basil Papadias , Harish Viswanathan
发明人： Xiaodong Li , Constantinos Basil Papadias , Harish Viswanathan
IPC分类号： H04J11/00
CPC分类号： H04L27/2602 , H04B7/0669 , H04L1/0606 , H04L1/0656 , H04L27/2607 , H04L27/2626
摘要： Wireless communications for frequency-selective fading channels is realized by employing a system including orthogonal frequency division multiplexing (OFDM) in combination with an at least two antenna transmit diversity arrangement. Specifically, OFDM converts a multipath channel into a plurality of narrowband subchannels each having flat fading. Then, the signals on the same frequency subchannels of the at least two antennas are grouped together. Considering a first frequency subchannel, during a first OFDM time interval, a first signal and a second signal are transmitted on the first frequency subchannel from a first antenna (0) and from a second antenna (1), respectively. During a second OFDM time interval, a reverse sign (−) complex conjugate of the second signal and a complex conjugate of the first signal are transmitted from the first antenna and the second antenna, respectively. In a specific embodiment of the invention, reduced complexity in the implementation is realized by a reverse order complex conjugate and a reverse order, reverse sign (−) complex conjugate and judicious selection of the processed data signals in order to transmit the appropriate ones of the signals during the first and second OFDM intervals. Again, if the channel remains constant over the two OFDM intervals, diversity combination is realized for each frequency subchannel. In another embodiment of the invention, antenna-group hopping is employed in conjunction with pairing in time of the OFDM frequency subchannel signals to realize increased transmit diversity without rate loss.
摘要翻译：用于频率选择性衰落信道的无线通信通过采用包括正交频分复用（OFDM）与至少两个天线发射分集布置的系统来实现。具体地，OFDM将多路径信道转换成各自具有平坦衰落的多个窄带子信道。然后，将至少两个天线的相同频率子信道上的信号分组在一起。考虑到第一频率子信道，在第一OFDM时间间隔期间，分别从第一天线（0）和第二天线（1）在第一频率子信道上发送第一信号和第二信号。在第二OFDM时间间隔期间，分别从第一天线和第二天线发送第二信号的反向符号（ - ）复共轭和第一信号的复共轭。在本发明的具体实施例中，实现方式的复杂度降低通过反向顺序复共轭和反向顺序，反向符号（ - ）复共轭和被处理数据信号的明智选择来实现，以便传输适当的信号在第一和第二OFDM间隔期间。再次，如果信道在两个OFDM间隔上保持恒定，则对于每个频率子信道实现分集组合。在本发明的另一个实施例中，天线组跳频与OFDM频率子信道信号的时间配对结合使用，以实现增加的发射分集而不发生速率损失。

2. 发明授权

US07035238B1 Code assignment in a CDMA wireless system 有权
标题翻译： CDMA无线系统中的码分配
公开(公告)号：US07035238B1
公开(公告)日：2006-04-25
申请号：US09353460
申请日：1999-07-13
申请人： Jiunn-Tsair Chen , Gerard Joseph Foschini , Constantinos Basil Papadias
发明人： Jiunn-Tsair Chen , Gerard Joseph Foschini , Constantinos Basil Papadias
IPC分类号： H04B7/216
CPC分类号： H04J13/18 , H04B1/7097 , H04J13/004
摘要： A CDMA wireless communication system for communicating with wireless terminals. The system comprises a channel estimator for determining characteristics of the wireless channels of the wireless terminals. The channel characteristics are used by a code optimizer to assign spreading codes to the wireless terminals. In one embodiment, the code optimizer utilizes an iterative code optimization algorithm and maintains a processing set of wireless terminals. The code optimizer chooses target wireless terminals and performs a random code search in order to find an improved code for the target wireless terminal. The improved code found in the random code search is further improved by performing a gradient search of codes in the signal space in the vicinity of the improved code and by performing a gradient search of transmission delays. The improved codes are transmitted to the wireless terminals for use in reverse link communication.
摘要翻译：一种用于与无线终端进行通信的CDMA无线通信系统。该系统包括用于确定无线终端的无线信道的特性的信道估计器。信道特性被代码优化器用于向无线终端分配扩展码。在一个实施例中，代码优化器利用迭代代码优化算法并维护无线终端的处理集合。代码优化器选择目标无线终端，并执行随机码搜索，以找到目标无线终端的改进代码。通过对改进码附近的信号空间中的码进行梯度搜索，并通过执行传输延迟的梯度搜索来进一步改进在随机码搜索中发现的改进码。改进的代码被发送到无线终端以用于反向链路通信。

3. 发明授权

US06301293B1 Detectors for CDMA systems 有权
标题翻译： CDMA系统检测器
公开(公告)号：US06301293B1
公开(公告)日：2001-10-09
申请号：US09129479
申请日：1998-08-04
申请人： Howard C. Huang , Constantinos Basil Papadias , Laurence Eugene Mailaender
发明人： Howard C. Huang , Constantinos Basil Papadias , Laurence Eugene Mailaender
IPC分类号： H04K100
CPC分类号： H04B1/71055 , H04B1/7093 , H04B1/7103 , H04B1/7115
摘要： Linear space-time multiuser detectors are described that combine array processing, rake detection, and multiuser detection and that satisfy a minimum mean-squared error criteria. Both embodiments can be implemented adaptively so as to account for unknown sources of interference. The adaptive implementation of the first embodiment of a linear space-time detector requires explicit estimates of the channel coefficients. On the other hand, the adaptive implementation of the second embodiment does not require these estimates since they can be adaptively obtained. Both of these detectors provide significant performance advantages over single-user space-time detectors and over multiuser detectors which do not account for CDMA interference from unknown sources.
摘要翻译：描述了组合阵列处理，耙检测和多用户检测并且满足最小均方误差准则的线性时空多用户检测器。可以自适应地实施两个实施例，以便考虑未知的干扰源。线性时空检测器的第一实施例的自适应实现需要对信道系数的显式估计。另一方面，第二实施例的自适应实现不需要这些估计，因为它们可以被自适应地获得。这两个检测器都比单用户空间时间检测器和多用户检测器提供了显着的性能优势，这些检测器不考虑来自未知来源的CDMA干扰。

4. 发明授权

US06452916B1 Space-time spreading method of CDMA wireless communication 有权
标题翻译： CDMA无线通信的时空传播方法
公开(公告)号：US06452916B1
公开(公告)日：2002-09-17
申请号：US09285578
申请日：1999-04-02
申请人： Bertrand M. Hochwald , Thomas Louis Marzetta , Constantinos Basil Papadias
发明人： Bertrand M. Hochwald , Thomas Louis Marzetta , Constantinos Basil Papadias
IPC分类号： H04B7216
CPC分类号： H04B7/0615 , H04B1/707
摘要： We describe a method for CDMA transmission of sets of data symbols to users that are organized into one or more user groups. Each user group is paired with a group of spreading codes, referred to as a “code group.” Each set of data symbols that are destined for respective users of a given user group is transmitted in the form of two or more distinct signal sequences. Each such signal sequence is transmitted from a respective one of two or more transmitting antennas. Each signal sequence is a linear combination of spreading code sequences belonging to the corresponding code group. Within each of these linear combinations, each spreading code sequence that appears has a scalar coefficient. Each of these scalar coefficients is a linear combination of pertinent data symbols (i.e., data symbols destined for users in the given user group) or of complex conjugates of pertinent data symbols.
摘要翻译：我们描述一种用于将组数据符号的CDMA传输到组织成一个或多个用户组的用户的方法。每个用户组与一组扩展码配对，称为“代码组”。以给定用户组的各个用户为目的地的每组数据符号以两个或多个不同信号序列的形式发送。每个这样的信号序列从两个或更多个发射天线中的相应一个发射。每个信号序列是属于相应代码组的扩展码序列的线性组合。在这些线性组合的每一个中，出现的每个扩展码序列具有标量系数。这些标量系数中的每一个是相关数据符号（即，给定用户组中的用户的数据符号）或相关数据符号的复共轭的线性组合。

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