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91. 发明专利

DE69707859D1 未知
公开(公告)号：DE69707859D1
公开(公告)日：2001-12-06
申请号：DE69707859
申请日：1997-04-25
申请人： ERICSSON INC
发明人： CHENNAKESHU SANDEEP , RYDBECK NILS , HASSAN AMER , REINHOLD L , IRVIN R
IPC分类号： H04Q7/38 , H04B7/15 , H04B7/185
摘要： A communication system provides efficient satellite communication in rural, remote, or sparsely populated areas, or in areas lacking a conventional telephone infrastructure, or in special purpose uses such as airport coverage. Subscribers in such areas communicate with the satellite via a simple, highly modular entry node located in a local area to be served. Subscriber units provide subscribers with access to the system. The subscriber units are connected to the entry node via local access loops provided by point-to-point wireless links between the subscriber units and the entry node. The entry node internally switches local traffic among subscribers and connects traffic to outside circuits, via wireless links with the satellite, as appropriate. The outside circuits are provided by the cooperative working of the satellite, an entry-node controller, and an earth station. The wireless links between the satellite and the entry node and the local access loops may operate at the same or different frequencies. If they operate at different frequencies, a frequency translator in the entry node controller matches the different frequencies. A subscriber unit may be used to provide the subscribers with access to the system such that speech compression and decompression takes place in the subscriber unit itself to avoid the effects of tandem coder/decoders.

92. 发明专利

BR9812914A 未知
公开(公告)号：BR9812914A
公开(公告)日：2000-08-08
申请号：BR9812914
申请日：1998-09-30
申请人： ERICSSON INC
发明人： CHENNAKESHU SANDEEP , MOLNAR KARL
IPC分类号： H04L27/22 , H04L7/00 , H04L7/04 , H04L7/08 , H04L27/233
摘要： A method and apparatus for synchronizing and demodulating radio wave signals transmitted in frame format with an unique word, involving correcting the frequency offset of the received signal and differentially correlating the frequency corrected signal with the unique word, A first timing estimate is further refined by a 2-D search between frequency and time and a first frequency estimate is further refined by quadratic interpolation. The finely synchronized signal is demodulated using a Viterbi-based demodulator.

93. 发明专利

AU2596000A Mlse using look up tables for multiplication 未知
公开(公告)号：AU2596000A
公开(公告)日：2000-08-07
申请号：AU2596000
申请日：1999-12-29
申请人： ERICSSON INC
发明人： CHENNAKESHU SANDEEP , ZANGI KAMBIZ , BOTTOMLEY GREGORY E
IPC分类号： H04L27/01 , H04L25/03 , H04L27/00
摘要： The present invention involves demodulation of radio signals modulated with M-ary modulation in the presence of intersymbol interference distortion. The invention presents a method for reducing the number of multiplications needed to implement a maximum-likelihood-sequence-estimation (MLSE) equalizer for signals modulated with M-ary modulation. In exemplary embodiments of the present invention, the number of multiplications is reduced by pre-computing certain values needed for the determination of the branch metric and storing these pre-computed values in a product table. When a branch metric computation is to be made, whether it is an Euclidean branch metric computation or an Ungerboeck branch metric computation, certain multiplication operations are replaced by simple table look-up operations. As a result, the power efficiency and speed of the system are increased. Any receiver that demodulates signals that are modulated with M-ary modulation can be implemented using the present invention. The resulting demodulator will have a lower complexity than existing demodulators.

94. 发明专利

AU721014B2 Satellite communication system for local-area coverage 未知
公开(公告)号：AU721014B2
公开(公告)日：2000-06-22
申请号：AU2941397
申请日：1997-04-25
申请人： ERICSSON INC
发明人： CHENNAKESHU SANDEEP , RYDBECK NILS , HASSAN AMER , REINHOLD STANLEY L , IRVIN DAVID R
IPC分类号： H04Q7/38 , H04B7/15 , H04B7/185
摘要： A communication system provides efficient satellite communication in rural, remote, or sparsely populated areas, or in areas lacking a conventional telephone infrastructure, or in special purpose uses such as airport coverage. Subscribers in such areas communicate with the satellite via a simple, highly modular entry node located in a local area to be served. Subscriber units provide subscribers with access to the system. The subscriber units are connected to the entry node via local access loops provided by point-to-point wireless links between the subscriber units and the entry node. The entry node internally switches local traffic among subscribers and connects traffic to outside circuits, via wireless links with the satellite, as appropriate. The outside circuits are provided by the cooperative working of the satellite, an entry-node controller, and an earth station. The wireless links between the satellite and the entry node and the local access loops may operate at the same or different frequencies. If they operate at different frequencies, a frequency translator in the entry node controller matches the different frequencies. A subscriber unit may be used to provide the subscribers with access to the system such that speech compression and decompression takes place in the subscriber unit itself to avoid the effects of tandem coder/decoders.

95. 发明专利

BR9713063A 未知
公开(公告)号：BR9713063A
公开(公告)日：2000-04-11
申请号：BR9713063
申请日：1997-11-12
申请人： ERICSSON INC
发明人： BOTTOMLEY GREGORY E , RAMESH RAJARAM , DENT PAUL W , CHENNAKESHU SANDEEP
IPC分类号： H04B7/26 , H04B1/707 , H04B1/709
摘要： The disclosure presents a number of reduced complexity architectures for despreading direct sequence spread spectrum communications signals. In a first despreading architecture for a sequence removal unit, received chip-spaced complex samples are negated in accordance with the processed phase of a complex spreading sequence. Furthermore, the in-phase and quadrature phase sample values are switched for each other in accordance with the processed phase. In a second despreading architecture, in a sequence removal unit, received chip-spaced complex samples are processed in the logarithmic domain, with the phase of the complex spreading sequence added to the detected phase, and the resulting complex signal then converted back to Cartesian coordinates. In a third despreading architecture for a correlator, sequence removal and correlation are performed in the logarithmic domain with the amplitudes and phases for the resulting complex signal arithmetically averaged and then converted back to Cartesian coordinates. In a fourth despreading architecture also for a correlator, sequence removal and correlation are performed in the logarithmic domain using circular averaging. In a fifth despreading architecture also for a correlator, wherein multiple component sequences are combined together to form an overall sequence, and wherein one of the multiple component sequences is shared by all channels, a common sequence removal is provided for removal of the shared sequence from all channels. The resulting signals are then sent to a plurality of individual correlators for removal of channel specific sequences.

96. 发明专利

AU717509B2 Apparatus and method for transmitting and receiving a signaling message in a communication system 未知
公开(公告)号：AU717509B2
公开(公告)日：2000-03-30
申请号：AU3000697
申请日：1997-05-06
申请人： ERICSSON INC
发明人： RYDBECK NILS RUTGER CARL , CHENNAKESHU SANDEEP
IPC分类号： H04B7/26 , H04B7/15 , H04W68/00 , H04W68/02 , H04Q7/38 , H04Q7/32
摘要： A communication system is disclosed as including a plurality of mobile radio telephones, a control unit for transmitting a signaling message to an intended mobile radio telephone, and at least one paging channel through which the control unit is able to transmit the signaling message at varying margin levels. The control unit initially transmits the signaling message at a specified margin level for a predetermined number of attempts and progressively continues to transmit the signaling message at margin levels greater than the specified margin level until the intended mobile radio telephone receives the signaling message. The mobile radio telephones are able to synchronize to the paging channel, monitor messages on the paging channel when the mobile radio telephone is synchronized thereto, receive messages on the synchronized paging channel, and provide a signal to alert a user of the mobile radio telephone that a message is received through the paging channel at a margin level greater than the specified margin level. The alert signal is provided in the form of a visual indicator, an audible indicator, and/or a vibration mechanism.

97. 发明专利

AU716719B2 High power short message service using TDMA frames 未知
公开(公告)号：AU716719B2
公开(公告)日：2000-03-02
申请号：AU1425497
申请日：1996-12-23
申请人： ERICSSON INC
发明人： CHENNAKESHU SANDEEP , RYDBECK NILS , HASSAN AMER A , DENT PAUL W
IPC分类号： H04B7/26 , H04B7/005 , H04B7/185 , H04W52/06 , H04W52/48
摘要： A method and system for transmitting short data messages in a control station-based TDMA radiocommunication system. According to exemplary embodiments, selected TDMA frames are assigned as message frames, and one or more data slots from each message frame are assigned to transmitter/receivers. Data messages can be encoded and transmitted multiple times, at an increased power level, from a control station to a transmitter/receiver over the appropriate data slots in each message frame. The selected TDMA frames are preferably slow associated control channel frames.

98. 发明专利

DE69604303D1 未知
公开(公告)号：DE69604303D1
公开(公告)日：1999-10-21
申请号：DE69604303
申请日：1996-12-23
申请人： ERICSSON INC
发明人： CHENNAKESHU SANDEEP , RYDBECK NILS , HASSAN AMER , DENT PAUL
IPC分类号： H04B7/26 , H04B7/005 , H04B7/185 , H04W52/06 , H04W52/48
摘要： A method and system for transmitting short data messages in a control station-based TDMA radiocommunication system. According to exemplary embodiments, selected TDMA frames are assigned as message frames, and one or more data slots from each message frame are assigned to transmitter/receivers. Data messages can be encoded and transmitted multiple times, at an increased power level, from a control station to a transmitter/receiver over the appropriate data slots in each message frame. The selected TDMA frames are preferably slow associated control channel frames.

99. 发明专利

BR9711877A 未知
公开(公告)号：BR9711877A
公开(公告)日：1999-08-24
申请号：BR9711877
申请日：1997-09-29
申请人： ERICSSON INC
发明人： WANG YI-PIN E , CHENNAKESHU SANDEEP , DENT PAUL , BALACHANDRAN KUMAR
IPC分类号： H03M13/37 , G06F11/10 , H03M13/00 , H03M13/29 , H04L1/00 , H04L1/06 , H04L1/18
摘要： The invention relates to a method for decoding a received codeword repeated at a receiver station through diversity means, wherein each repetition of the received codeword includes an information vector and redundancy vector. The method comprises inputting one or more of said information vectors (Î) in said received codewords to a series of parallel decoders (106), inputting one or more of said redundancy vectors (P1, ..., PL) in said received codewords to said parallel decoders (106), decoding the information vectors separately in said parallel decoders (106) to generate a plurality of estimates ( @ ) of the information sequence, and combining (108) at least two estimates of the information sequence to generate a composite estimate.

100. 发明专利

AU2216799A Method and apparatus for multipath delay estimation in direct sequence spread spectrum communication systems 未知
公开(公告)号：AU2216799A
公开(公告)日：1999-07-26
申请号：AU2216799
申请日：1999-01-12
申请人： ERICSSON INC
发明人： SOUROUR ESSAM , BOTTOMLEY GREG , RAMESH RAJARAM , CHENNAKESHU SANDEEP
IPC分类号： H04B1/711 , H04B1/709 , H04B1/7113 , H04B7/26 , H04B1/707
摘要： Multipath delay estimation of a direct sequence spread spectrum (DS-SS) signal transmitted in a multipath fading channel is accomplished by measuring the envelope of the signal to determine a new delay estimate. Delay estimates are also obtained in ray strength order, by subtracting out the influence of the stronger rays on the weaker ones. This subtraction approach can be performed iteratively, allowing further refinement of the delay estimates. Delay estimates can also be determined by minimizing the mean square error (MSE) between a measured correlation function and a modeled correlation function. The minimum mean square error (MMSE) approach can performed iteratively, to further refine the delay estimates. Maximum likelihood (ML) delay estimates can also be obtained by exploiting side information regarding the transmit and receive pulse shapes.

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