Walsh Functions Patents (Class 370/209)
  • Publication number: 20080181096
    Abstract: Aspects describe a Fast Hadamard Transform that is common to multiple mobile devices. A scrambled sequence produced by the Fast Hadamard Transform can be utilized to decode access-based handoff probes from multiple terminals within a wireless communications system. A Walsh Sequence can be scrambled with a common random sequence to produce a scrambled sequence. At least a portion of the scrambled sequence is included in an access probe.
    Type: Application
    Filed: January 29, 2008
    Publication date: July 31, 2008
    Applicant: QUALCOMM INCORPORATED
    Inventors: Aamod Khandekar, Alexei Gorokhov, Naga Bhushan
  • Patent number: 7400614
    Abstract: Downlink diversity in a CDMA system is provided by employing Walsh codes in conjunction with M transmit antennas at a common base station serving K mobiles, where M may or may not be to equal to K. The present invention provides methods and apparatus for improving downlink diversity in a CDMA system. Each transmit antenna transmits a signal representing the result of the modulation of Walsh codes by data signals for each of the K mobiles, assuming there is data pertaining to a particular mobile. The assignment of Walsh codes is accomplished in accordance with a transmission matrix T. The transmission matrix maps the user data symbols onto the Walsh codes for each antenna and is preferably designed such that its columns are representative of the transmit antennas and orthogonal.
    Type: Grant
    Filed: October 29, 2002
    Date of Patent: July 15, 2008
    Assignee: Lucent Technologies Inc.
    Inventors: R. Michael Buehrer, Robert Atmaram Soni, Jiann-An Tsai
  • Patent number: 7394793
    Abstract: A preamble generation method and apparatus are provided for improving transmit diversity by changing a preamble structure in a broadband wireless communication system using multiple antennas based on a multiple input multiple output (MIMO) scheme. First pilot tones associated with different antennas are selected. The first pilot tones are multiplied by different first Walsh codes. Second pilot tones associated with the same antenna are sequentially selected along a frequency axis. The second pilot tones are multiplied by a second Walsh code. Preambles are generated by assigning, to at least two symbol durations, output signals multiplied by the first and second Walsh codes. Consecutive pilot tones during each of the at least two symbol durations are spaced by one pilot tone, and code streams of the first and second Walsh codes are alternately multiplied by the pilot tones. The preamble structure has orthogonality between the antennas using frequency, time and code domains.
    Type: Grant
    Filed: March 11, 2005
    Date of Patent: July 1, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Won-Il Roh, Jae-Ho Jeon, Soon-Young Yoon, Seung-Joo Maeng
  • Publication number: 20080137526
    Abstract: The pilots of a wireless system are arranged to reduce inter-sector interference by establishing a systematic assignment of pilots across the system. In one embodiment, the pilots are differently coded and directionally positioned within a cell such that the same pilot from adjacent cells do not overlap. In one embodiment, Walsh codes are used to create the differently coded pilot signals.
    Type: Application
    Filed: January 9, 2007
    Publication date: June 12, 2008
    Applicant: Adaptix, Inc.
    Inventors: Zhucheng Jiang, Haitao Wang
  • Publication number: 20080130482
    Abstract: A wireless communications network, including a base station (10) and wireless units (UE), is disclosed. The wireless units (UE) request a connection with the base station (10) by the transmission of a preamble within time slots designated by the base station (10). The disclosed preambles are Walsh Hadamard code symbols, repeated a number of times so as to have the same length as a cell-specific scrambling code. The wireless unit (UE) requesting a connection pseudo-randomly selects a time slot from those available, and one of the Walsh Hadamard code symbols, replicates the code symbol into a spread interleaved bitstream, scrambles this bitstream and transmits it to the base station (10). Upon receipt, the base station (10) applies the incoming bitstream to a matched filter (98) to descramble the signal, following which the symbol is de-interleaved by way of a sequence of delay lines (100).
    Type: Application
    Filed: January 25, 2008
    Publication date: June 5, 2008
    Inventor: Anand G. Dabak
  • Patent number: 7376076
    Abstract: The present invention relates to Walsh Code Allocation (WCA) field in the Packet Data Control Channel. One of the embodiments of the WCA field is use of the WCA field as Last Walsh Code Index (LWCI) field in the message format of the PDCCH. The LWCI field indicates the corresponding last code index or the corresponding number of Walsh codes in a Walsh Code Index (WCI) Table/List/Set. In alternative embodiments, the WCA indicates a general set of Walsh codes or a specific set of Walsh codes in the WCI table. The WCA fields may or may not be used with one of power ranking and sequential decoding, but is preferable used. The WCA field has various advantages including but not limited to efficient use of system resources.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: May 20, 2008
    Assignee: LG Electronics Inc.
    Inventors: Cheol Woo You, Young Woo Yun, Jong Hoe An, Suk Hyon Yoon, Young Jo Lee, Ki Jun Kim, Young Cho Kim
  • Patent number: 7369486
    Abstract: An apparatus for increasing channel capacity in a mobile communication system using a hybrid phase shift keying (HPSK) modulation method. The method includes a walsh code control unit for checking sequences of walsh codes respectively outputted from a first walsh code unit and a second walsh code unit, a walsh rotator for generating a plurality of repeated complex functions and outputting them and a rotator control unit for selecting the repeated complex functions outputted from the walsh rotator according to the sequence of the walsh codes outputted from the first walsh code unit and the second walsh code unit. The method can use all walsh codes and increase reverse channel capacity.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: May 6, 2008
    Assignee: LG Electronics Inc.
    Inventor: Kyung-Ho Min
  • Publication number: 20080080432
    Abstract: Two types of access probe messages are defined: a first when a mobile station has not yet been assigned a media access code index (MAC ID), and a second when a mobile station already has a MAC ID assigned by the base stations in the active set. Base stations can differentiate between the first and second types of access probes according to the scrambling sequence used. In the second type, while different MAC IDs are used by each of the mobile stations in the sector, they are all scrambled according to a similar scrambling sequence defined specifically for these second types of access probes. The rake receivers used in such networks are configured to repeat the rake finger processing after CP removal, DFT, de-channelizing, and IDFT, thereby reducing their complexity.
    Type: Application
    Filed: September 4, 2007
    Publication date: April 3, 2008
    Inventors: Jianmin Lu, Yunsong Yang, Zhigang Rong
  • Patent number: 7352713
    Abstract: A multiplexed signal quality display system, method, and program, and recorded medium where the program is recorded. The invention measures the quality of a multiplexed signal from a communication device wherein a band width to be used and the number of communication channels capable of being accommodated are determined by a diffusion code length, and channels to be used having the number of communication channels, which are determined by a diffusion code length, are decided in terms of a diffusion code number affixed to the type of the diffusion code, to effect communication while ensuring multi-channel communication lines in one and same band.
    Type: Grant
    Filed: June 8, 2002
    Date of Patent: April 1, 2008
    Assignee: Advantest Corporation
    Inventors: Satoshi Koizumi, Juichi Nakada, Eiji Nishino, Hideki Ichikawa
  • Patent number: 7349421
    Abstract: A method is taught for transmitting message signals in a communication system having a new call entering the communication system and Walsh codes that can be active and inactive. The method includes dividing the Walsh codes into bins and determining the number of active Walsh codes in the bins. Selecting a Walsh code in accordance with the Walsh code number determination and assigning the selected Walsh code to the new call are set forth.
    Type: Grant
    Filed: April 3, 2006
    Date of Patent: March 25, 2008
    Assignee: QUALCOMM Incorporated
    Inventor: Abhijit G. Shanbhag
  • Patent number: 7346038
    Abstract: A multicarrier direct-sequence code-division multiple-access (MC-DS/CDMA) communications system is provided. A code tree of two-dimensional orthogonal variable spreading factor (2D-OVSF) codes is then generated for the system. To generate the code tree, a set of existing M1×N1 2D-OVSF matrices, in the form of A(i)(M1×N1) for i={1, 2, . . . , K1} is selected as seed matrices. M1 represents the number of available frequency carriers in the MC-DS/CDMA system, and N1 represents a spreading factor code length. Another set of existing M2×N2 2D-OVSF matrices, in the form of B2(i)(M2×N2) for i={1, 2, . . . , K2} is then selected as mapping matrices. The mapping matrices are used to generate corresponding children matrices.
    Type: Grant
    Filed: April 4, 2003
    Date of Patent: March 18, 2008
    Assignee: Accton Technology Corporation
    Inventors: Guu-Chang Yang, Chia-Ming Yang, Pei-Hsuan Lin
  • Publication number: 20080043859
    Abstract: A system and device communicates data. A modulation and mapping circuit modulates and maps data symbols into a plurality of multiple subcarriers that are orthogonal to each other based on a fixed or variable symbol rate. A frequency domain spreader circuit is operatively connected to the modulation and mapping circuit and spreads the multiple subcarriers over the frequency domain.
    Type: Application
    Filed: August 16, 2006
    Publication date: February 21, 2008
    Applicant: HARRIS CORPORATOIN
    Inventor: Christopher D. MOFFATT
  • Patent number: 7333469
    Abstract: A method for compensating for the Doppler effect in a communication system where messages are transmitted at a low data rate to a user terminal that is inside a building. The method comprising acquiring a pilot signal prior to the user terminal entering the building; placing the user terminal into a deep paging mode prior to the user terminal entering the building; tracking Doppler as the user terminal proceeds into the building; and monitoring an auxiliary paging channel after activating said deep paging mode.
    Type: Grant
    Filed: June 23, 2003
    Date of Patent: February 19, 2008
    Assignee: Qualcomm Incorporated
    Inventor: Leonard N. Schiff
  • Patent number: 7324436
    Abstract: A method of determining useable combinations of variables for transmitting a subpacket of an encoder packet in a communication system is disclosed. First, an arbitrary combination from a plurality of all combinations of transmission variables is selected based on a number of currently useable Walsh codes and channel environment. Next, an arbitrary MPR is determined based on a number of useable encoder packet bits, a number of useable slots, and the number of currently useable Walsh codes, all of which belong to the selected arbitrary combination transmission variables. Thereafter, a final MPR, which is the smallest one of MPR values of a MPR set that corresponds to the number of useable encoder packet bits and the number of useable slots, is determined, and a final number of Walsh codes is calculated based on the number of useable encoder packet bits, the number of useable slots, and the determined final MPR.
    Type: Grant
    Filed: April 25, 2003
    Date of Patent: January 29, 2008
    Assignee: LG Electronics Inc.
    Inventors: Cheol Woo You, Ki Jun Kim, Young Woo Yun, Soon Yil Kwon
  • Patent number: 7321610
    Abstract: In signal detection system and method implemented to reduce the effects of interference in multi-user detection systems, a receiver defines a frame of symbols containing at least one window based upon a number of user signals contained in a received signal r(t). A symbol amplitude of a single-user in the multi-user system is approximated over the window of the frame based on a number of reflected signal paths of the received user signal. A perturbative correction value is calculated based upon a correlation matrix. An estimation of the symbol amplitude of the single-user signal is calculated over one or a number of windows of the frame. The single-user signal is detected when the symbol amplitudes of the entire signal within the frame has been calculated. To reduce the number of interfering users in a multicell CDMA system, the symbol codes are modified to include an even code and an odd code.
    Type: Grant
    Filed: August 15, 2002
    Date of Patent: January 22, 2008
    Assignee: Industrial Technology Research Institute
    Inventor: Chun Chian Lu
  • Patent number: 7308019
    Abstract: A flexible Fast Walsh Transform circuit provides configurable FWT sizes, and is suitable for use in radio receivers where the received signal may be generated using varying spreading codes and/or varying numbers of multi-codes. Such signal types are commonly encountered in wireless communication systems like those based on the Wideband CDMA (W-CDMA) or IS-2000 (cdma2000) standards, and particularly with the higher data rate provisions of those standards. In one application, a RAKE receiver includes RAKE fingers that each include one of the flexible FWT circuits, such that each finger despreads the received signal using variably sized FWTs in accordance with the characteristics of the received signal. The flexibility in FWT sizing may derive from, for example, the inclusion of separately selectable but differently sized FWT circuits, or from the inclusion of a configurable FWT circuit capable of generating different sizes of FWTs.
    Type: Grant
    Filed: May 20, 2002
    Date of Patent: December 11, 2007
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Gregory E. Bottomley, Ali S. Khayrallah
  • Patent number: 7302025
    Abstract: An efficient approach to generating the bias resulting during the joint equalization/decoding of a Complementary-Code-Keying (CCK) based system is provided that includes a bias generator system having a plurality of inputs responsive only to feedback filter coefficients, the bias generator generating, based upon said feedback filter coefficients, a plurality of output signals corresponding to the bias of a Fast Walsh Transform system for cancelling the bias.
    Type: Grant
    Filed: April 3, 2004
    Date of Patent: November 27, 2007
    Assignee: Analog Devices, Inc.
    Inventor: Ganesh Ananthaswamy
  • Patent number: 7302020
    Abstract: A bus system includes multiple devices and a bus. The bus is connected to each device. Each device may include a type of input/output (I/O) device, such as a random access memory (RAM) or a microprocessor. The bus transfers data between devices. Data of each device may be encoded with a unique orthogonal code. Encoded data of each device may be superimposed onto a bus so as to permit substantially concurrent communication on the bus by each of the devices. Data of each device is decoded by correlating the encoded data with the unique code used to form the encoded data.
    Type: Grant
    Filed: May 20, 2002
    Date of Patent: November 27, 2007
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Karl Joseph Bois, David W. Quint, Vaishnav Srinivas
  • Patent number: 7301892
    Abstract: A mobile station comprising a decoder circuit and a control circuit. The decoder circuit may be configured to retrieve mask information from a packet data control channel. The control circuit may be configured to (i) determine whether the mask information is valid and (ii) when the mask information is valid, update a current mask of the mobile station with the mask information.
    Type: Grant
    Filed: June 1, 2005
    Date of Patent: November 27, 2007
    Assignee: VIA Telecom Co., Ltd.
    Inventors: Oiang Shen, Kraig Anderson, Insung Kang
  • Patent number: 7277382
    Abstract: The invention provides a method and system for the generation of Hybrid Walsh orthogonal codes for CDMA spreading and channelization encoding and fast decoding. Current art uses real Walsh orthogonal codes for CDMA spreading and orthogonal channelization. Hybrid Walsh codes are complex Walsh codes that have a isomorphic one-to-one correspondence with the discrete Fourier transform (DFT) codes and are derived by separate permutations of real Walsh codes for the real and for the imaginary components. Hybrid Walsh codes are the best approximation to the DFT within the constraints of a unity norm, 4-phases on real and imaginary axes, orthogonality, and therefore are a preferred choice for a complex Walsh code. The invention discloses a method for the Hybrid Walsh encoder to be generalized by combining with DFT, quasi-orthogonal PN codes, and other codes using a tensor product construction, direct sum construction, and functional combining.
    Type: Grant
    Filed: January 9, 2001
    Date of Patent: October 2, 2007
    Inventor: Urbain Alfred von der Embse
  • Patent number: 7272110
    Abstract: The present invention relates to a mobile communication system, and more particularly, to a method of allocating a Walsh code resource. The present invention includes determining an available maximum data rate by comparing a channel information value of a forward link with a first threshold value, determining a data rate based on a quantity of data to be transmitted, terminating to allocate the walsh codes or determining a number of the walsh codes to be requested for the data according to a comparison between the data rates, and determining a number of walsh codes for other terminals by checking a number of remaining walsh codes excluding the number of the requested walsh codes from available walsh codes.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: September 18, 2007
    Assignee: LG Electronics Inc.
    Inventors: Young Jo Lee, Young Woo Yoon, Jong Hoe An, Suk Hyon Yoon, Cheol Woo You
  • Publication number: 20070211620
    Abstract: A communication system distributes, in the time domain, acknowledgment transmissions by a group of access terminals sharing a same time domain resource. A position of one or more access terminals in the group of access terminals is determined and each of the one or more access terminals then sends an acknowledgment transmission, such as an acknowledgment or negative acknowledgement, in a time slot that is N time slots after the shared time domain resource, where N is a function of the position of the access terminal in the group of access terminals.
    Type: Application
    Filed: January 22, 2007
    Publication date: September 13, 2007
    Applicant: MOTOROLA, INC.
    Inventors: Sean M. McBeath, Danny T. Pinckley, John D. Reed, Jack A. Smith
  • Publication number: 20070211619
    Abstract: A method and apparatus for wireless transmission from a mobile unit to a base station includes multiplexing a pilot signal and a data signal, wherein the data signal operates at a data rate by splitting the data signal into a plurality of data streams; applying a pilot gain to the pilot channel, wherein the data gain and the pilot gain are a function of the data rate; and combining the plurality of data streams and the pilot signal into a subset of sub-carriers. The subset of sub-carriers are transmitted using Discrete Fourier Transform Spread OFDMA.
    Type: Application
    Filed: November 29, 2006
    Publication date: September 13, 2007
    Applicant: Motorola, Inc.
    Inventors: Louay Jalloul, Tzu-Chung Frank Hsieh
  • Patent number: 7248698
    Abstract: A system for generating pseudorandom codes using a register which contains an identification of the code tree leg of the desired code and a counter which outputs a successive binary sequence. The output from the counter is bit-by-bit ANDed with the output of the register, and those outputs are XORed together to output a single bit. As the counter is sequenced, each count results in a different bit that is output from the XOR gate, resulting in the desired code.
    Type: Grant
    Filed: October 23, 2001
    Date of Patent: July 24, 2007
    Assignee: InterDigital Technology Corporation
    Inventor: Edward L. Hepler
  • Patent number: 7239632
    Abstract: A converged network accessible by wireless client devices includes a wide area wireless network, a local area wireless network, and a gateway linked to the wide area and local area wireless networks for integrating access to the networks by the wireless client devices.
    Type: Grant
    Filed: June 17, 2002
    Date of Patent: July 3, 2007
    Assignee: Tatara Systems, Inc.
    Inventors: Asawaree Kalavade, Hong Jiang, Penny Chen
  • Patent number: 7239604
    Abstract: A code indexing system for a CDMA communication station that uses orthogonal variable spreading factor (OVSF) codes has a single number mapped to each code. The new code number itself not only provides the code signature, but it is also used for the OVSF code generation. In addition, the system provides easy and fast generation of the available code list without the help of look-up table. This capability improves the dynamic code assignment.
    Type: Grant
    Filed: April 23, 2004
    Date of Patent: July 3, 2007
    Assignee: InterDigital Technology Corporation
    Inventors: Younglok Kim, Jung-Lin Pan
  • Patent number: 7236512
    Abstract: Systems and techniques are disclosed relating to communications. The systems and techniques involve spread-spectrum communications using a scheduler, or similar component, configured to maintain a plurality of spreading sequence assignments and a plurality of available spreading sequences each being orthogonal to the assigned spreading sequences. The scheduler may also be configured to select a spreading sequence from a group of the available spreading sequences having the same length, the selected spreading sequence being generated from a block of codes and being selected based on the number of the available spreading sequences that can be generated using the same block of codes.
    Type: Grant
    Filed: August 20, 2003
    Date of Patent: June 26, 2007
    Assignee: Qualcomm Incorporated
    Inventors: Luca Blessent, Ashish N. Desai
  • Patent number: 7227836
    Abstract: A traffic channel transmission device for a CDMA communication system using a plurality of coding rates and orthogonal codes, determines a present channel condition and adaptively selects a coding rate and an orthogonal code according to the determination. In the device, a channel receiver receives a channel signal and a controller analyzes the received signal to decide an environment of a channel in service and generates a coding rate select signal and orthogonal code information according to the decision result. A channel transmitter includes a channel encoder for encoding transmission data at a coding rate selected according to the coding rate select signal and an orthogonal modulator for generating an orthogonal code according to the orthogonal code information to spread the encoded data with the generated orthogonal code, whereby the channel transmitter adaptively encodes and spreads the transmission data according to the channel environment.
    Type: Grant
    Filed: October 16, 2002
    Date of Patent: June 5, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Seung-Hyun Kong, Young-Ky Kim, Jae-Min Ahn, Soon-Young Yoon
  • Patent number: 7218617
    Abstract: A pilot channel transmission method is provided of transmitting a pilot channel through a downlink from a base station in a CDMA mobile communication system including base stations. Each base station is installed in one of a plurality of cells, uses a same frequency, and divides its channels using orthogonal codes uniquely assigned to the channels. Each of the cells is identified by multiplying a spreading code assigned to each base station by the channels spread by the orthogonal codes. In the pilot channel transmission method, when a plurality of orthogonal code sets, each of which includes a plurality of spreading codes assigned thereto, using by each base station, a pilot channel is assigned to each orthogonal code set, and at least one of the pilot channels is transmitted. The pilot channel can be provided with a symbol rate higher than the minimum symbol rate defined in the system.
    Type: Grant
    Filed: October 20, 2000
    Date of Patent: May 15, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masafumi Usuda, Yoshihiro Ishikawa
  • Patent number: 7200179
    Abstract: Input data is separated into a first data row and a second data row by a unit of a predetermined symbol. One of a plurality of orthogonal codes is selected in accordance with the separated second data row. The first data row is diffused using the selected code; and the diffused first data row is modulated and transmitted. When received, the signals are individually inversely diffused using the same plurality of orthogonal codes. An inversely diffused signal using a correct orthogonal code is selected and demodulated to obtain a first receiving data row. A second receiving data row corresponding to the correct orthogonal code is obtained; and the first and second receiving data rows are combined to obtain the received data.
    Type: Grant
    Filed: March 5, 2004
    Date of Patent: April 3, 2007
    Assignee: Sony Erission Mobile Communications Japan, Inc.
    Inventor: Masanori Sato
  • Patent number: 7173900
    Abstract: A method and an apparatus for generating a chip of a chip sequence based on a supplied chip position index and a supplied sequence index is provided by generating a basic sequence bit using a portion of the chip position index and the sequence index, and by generating different mask bits using different portions of the chip position index and the sequence index, the mask bits being used in conjunction with the basic sequence bit to generate the chip. Such a chip generation process increases the chip generation rate so that users requesting chips to be generated may be efficiently pipelined.
    Type: Grant
    Filed: June 26, 2002
    Date of Patent: February 6, 2007
    Assignee: Nortel Networks Limited
    Inventor: Ganesh Sundararajan
  • Patent number: 7154846
    Abstract: A forward link design is provided employing CDMA (code division multiple access) technologies in which time division multiplexing is employed between data and control information on the forward link to service multiple users per slot. Another forward link design employing CDMA (code division multiple access) technologies is provided in which code division multiplexing between data and control information is employed on the forward link to service multiple users per slot, which is preferably backwards compatible with legacy standards such as IS2000A. A reverse link design is also provided.
    Type: Grant
    Filed: October 24, 2001
    Date of Patent: December 26, 2006
    Assignee: Nortel Networks Limited
    Inventors: Xixian Chen, Neil N. McGowan, Khaled M. Islam, Ning Guo, Hong Ren, Litong Li
  • Patent number: 7116698
    Abstract: A generator of repetitive sets of spreading sequences comprising element (20), for counting and for forming an address and a table (30) containing L sets of S sequences, wherein the address contains q=1+log2S bits, in which one set among L (L=2q) sets is selected and wherein the log2S bits select one sequence among the S sequences in the set.
    Type: Grant
    Filed: June 13, 2001
    Date of Patent: October 3, 2006
    Inventors: Norbert Daniele, Dominique Noguet, Rosolino Lionti, Jean-René Lequepeys
  • Patent number: 7102994
    Abstract: A code group out of 32 code groups that a time division duplex (TDD) base station belongs to is to be indicated. A primary synchronization code is transmitted along with a plurality of secondary synchronization codes from the TDD base station. The plurality of secondary synchronization codes are derived from a row of a Hadamard matrix and the secondary synchronization codes are quadrature phase shift keying modulated. The code group of the TDD base station is indicated by the transmitted plurality of secondary synchronization codes and the 32 code groups are divided into a plurality of code group sets. Each of the code group sets is identified by using a different set of secondary synchronization codes.
    Type: Grant
    Filed: October 28, 2003
    Date of Patent: September 5, 2006
    Assignee: InterDigital Technology Corporation
    Inventors: Nadir Sezgin, Fatih M. Ozluturk
  • Patent number: 7095710
    Abstract: Methods and apparatus to improve the speed and reliability of decoders are presented herein. Namely, a priori knowledge of Walsh space information is used to increase the speed at which messages are decoded. In systems where control messages contain transmission parameters of concurrently transmitted packet data, a faster demodulation and decoding of control messages allows a receiver to demodulate the packet data sooner, so that a shorter buffer is needed to store the received packet data. The receiver uses the Walsh space from the previous successfully decoded message to first decode the current message. If the decoding attempt is unsuccessful, the receiver then uses a neighboring Walsh space to decode the current message.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: August 22, 2006
    Assignee: Qualcomm
    Inventor: Stein A. Lundby
  • Patent number: 7088267
    Abstract: A duplex-system digital-data transmitting apparatus includes a digital-data signal source which outputs serial data at a signal output end. The level of the data is converted by a first level converter circuit. The data is supplied to an FSK modulator circuit to be FSK-modulated. Carriers are, for example, at 11 MHz and 13 MHz and correspond to digital signals “1” and “0”, respectively. The modulated signal is amplified by a driver and is coupled to the human body by a capacitor of about 100 pF. When the human body comes into contact with an electrode, the modulated signal transmitted through the human body is amplified by a pre-amplifier, demodulated by a demodulator circuit, and shaped by a comparator. The level of the shaped signal is converted by a second level converter circuit, and the signal is supplied to a serial input end of a receiving unit. Transmission and reception are performed using a half-duplex system.
    Type: Grant
    Filed: December 1, 2000
    Date of Patent: August 8, 2006
    Assignee: Sony Corporation
    Inventor: Shigeru Tajima
  • Patent number: 7088673
    Abstract: A code controller partitions a set of orthogonal spreading codes into a plurality of subsets of orthogonal spreading codes and allocates and transmits the subsets of orthogonal spreading codes to users. A transmitter device partitions the received subset of orthogonal spreading codes into partitioned sets. The partitioned sets are further expanded to include complement codes of the orthogonal spreading codes and the codes are mapped into a code index to create a spreading code set. A window of contiguous multi-bit input data to be transmitted by the transmitter device is partitioned into equal-size subsets, which are then mapped to a data index, to create a data set. The data set is mapped to the spreading code set to create a multiplex of spreading codes, and the multiplex of spreading codes are then summed to form a code multiplex. The code multiplex can then be sent in one transmit opportunity.
    Type: Grant
    Filed: November 2, 2001
    Date of Patent: August 8, 2006
    Assignee: Intel Corporation
    Inventor: David M. Horne
  • Patent number: 7079592
    Abstract: The present invention relates to both of a bi-stage correlation calculation demodulation system, and a fast walsh block demodulation device at a receiver, wherein the bi-stage correlation calculation demodulation system has a characteristic of bi-stage correlation calculation in which the subsequent second-stage correlation calculations are dependent on the first-stage correlation calculation results by utilizing an incomplete orthogonal property within CCK codewords to arrange the CCK codewords operated in the first-stage correlation calculations and second-stage correlation calculations properly and respectively.
    Type: Grant
    Filed: June 14, 2002
    Date of Patent: July 18, 2006
    Assignee: Accton Technology Corporation
    Inventors: Cheng-Yuan Chang, Jie-Hau Huang, Hong-Chin Lin, Guu-Chang Yang, Yung-Hsien Chang, Hsuan-Ching Chao
  • Patent number: 7075885
    Abstract: Modulation codes for code division multiple access (CDMA) cellular communications systems that are mutually orthogonal may be generated as a sequence of Walsh codes. A method of assigning Walsh codes includes the steps of (404) receiving as input a status vector (200) for a Walsh code system of length 2n and a selected Walsh code length j=2n?k; (406)–(418) creating a new status vector for a selected Walsh code length of j from the status vector; (416) creating a search mask for the selected Walsh code length j; (418) creating a search sequence for the selected Walsh code length j; and (434)–(442) searching the search sequence for the next available Walsh code. The status vector is updated (500) to track the assignment and release of each Walsh code of each Walsh code length in the Walsh code system.
    Type: Grant
    Filed: December 3, 2001
    Date of Patent: July 11, 2006
    Assignee: Motorola, Inc.
    Inventors: Dean E. Thorson, Daniel J. Declerck
  • Patent number: 7061965
    Abstract: A Walsh code assigning apparatus includes a retaining unit retaining assignment order information about an order of assignment of the plural Walsh codes such that one Walsh code having a smaller bit length becomes unable to he orthogonally separated as being precedent over another Walsh code having a larger bit length and a controller including a retrieving unit retrieving an idle Walsh code having an assignment request bit length in accordance with the assignment order information retained in the retaining unit, and assigning unit assigning the idle Walsh code, which has been obtained by the retrieving unit, to the spreading code of a last-named communication channel for which the assignment request is issued.
    Type: Grant
    Filed: October 31, 2001
    Date of Patent: June 13, 2006
    Assignees: Fujitsu Limited, Mobile Techno Corp.
    Inventors: Mayumi Kodani, Shoichi Miyamoto, Ayanori Matsuda, Takuya Mori
  • Patent number: 7058151
    Abstract: A frequency and symbol timing synchronization apparatus for orthogonal frequency division multiplexed (OFDM) signals, and a method performed by the apparatus are provided. This apparatus includes an autocorrelation unit, a comparator, a peak flat detector, a frequency offset estimator, a frequency offset compensation unit, a cross correlation unit and a symbol timing synchronization unit. The autocorrelation unit receives data including a synchronizing symbol made up of at least three identical synchronizing signals, delays the received data by a predetermined delay amount, performs autocorrelation between the received data and the delayed data, normalizes an autocorrelated value, and outputs a normalized autocorrelated value. The comparator compares the normalized autocorrelated value with a predetermined threshold value. The peak flat detector detects as a flat section a section where the normalized autocorrelated value is equal to or greater than the threshold value.
    Type: Grant
    Filed: June 15, 2000
    Date of Patent: June 6, 2006
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Kwang-Chul Kim
  • Patent number: 7035663
    Abstract: A system and method for overlaying signals comprises an incumbent system, an overlay system, and a multi-access controller. The incumbent system is configured to format a first signal according to a protocol used with an incumbent protocol, such as a protocol used with a multi-point multi-channel distribution service (MMDS) system, and transmits the formatted first signal as an incumbent signal to the controller. The overlay system is configured to format a second signal according to a protocol used for an overlay protocol, such as a protocol used with a code division multiple access (CDMA) system, and transmits the formatted second signal to the controller as an overlay signal. The controller overlays the incumbent signal with the overlay signal to create a wireless complementary signal and transmits the wireless complementary signal via a network.
    Type: Grant
    Filed: October 30, 2001
    Date of Patent: April 25, 2006
    Assignee: Sprint Communications Company, L.P.
    Inventors: John W. Linebarger, Durga P. Satapathy
  • Patent number: 7027494
    Abstract: An orthogonal spread code for a mobile communication system is provided which increases an interference free window (IFW) interval as well as the element number of the orthogonal code set. A large synchronization (LS) code is generated by using an initial 2×2 matrix to generate magnified first and second square matrices. A third square matrix is then generated based on the first and second square matrices, and a code sequence is generated from the rows or columns of the third square matrix. In this manner, the inversely proportional relationship between the element number of the orthogonal code set and the IFW interval may be established, and used to avoid channel prediction errors and reduce power imbalance.
    Type: Grant
    Filed: November 28, 2001
    Date of Patent: April 11, 2006
    Assignee: LG Electronics Inc.
    Inventor: Dong-Wook Roh
  • Patent number: 7023872
    Abstract: A method is taught for transmitting message signals in a communication system having a new call entering the communication system and Walsh codes that can be active and inactive. The method includes dividing the Walsh codes into bins and determining the number of active Walsh codes in the bins. Selecting a Walsh code in accordance with the Walsh code number determination and assigning the selected Walsh code to the new call are set forth.
    Type: Grant
    Filed: August 6, 2001
    Date of Patent: April 4, 2006
    Assignee: Qualcomm Incorporated
    Inventor: Abhijit G. Shanbhag
  • Patent number: 7020175
    Abstract: A pilot signal enters a first MMSE receiver (201) and a second signal enters a second MMSE receiver (202). The first MMSE receiver (201) performs a channel estimate for the received pilot signal, determines a mean-square error of the pilot signal, and operates to minimize the mean-square error of the pilot estimate by constantly updating a weighting vector. An estimate of the pilot channel exits the first MMSE receiver (201). The MMSE weighting vector (206) is also fed into the second MMSE receiver (202) and is applied to the second channel. Symbol estimates (or in other embodiments, chip estimates) exit the second MMSE receiver (202) and enter channel circuitry (204), where normal channel processing occurs.
    Type: Grant
    Filed: January 22, 2001
    Date of Patent: March 28, 2006
    Assignee: Motorola, Inc.
    Inventor: Colin D. Frank
  • Patent number: 7012886
    Abstract: A method of allocating CDMA codes from a set of the same is provided for use in connection with a wireless network. The method includes, after identifying a desired size of the code to be allocated, determining if there exists a code of the desired size whose sibling is unavailable. If such a code is found, then it is allocated. Otherwise, it is determined if there exists a code of smaller than the desired size whose sibling is unavailable. When such a code (i.e., a code of smaller than the desired size whose sibling is unavailable) is found, a descendant thereof which has the desired size is allocated.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: March 14, 2006
    Assignee: Lucent Technologies Inc.
    Inventors: Steven K. Meier, Christopher D. Palm, Steven M. Welsh, John K. Burgess
  • Patent number: 7002901
    Abstract: A method for assigning orthogonal codes used for a first system and a second system in a CDMA system including channels of the first system for spreading a pilot signal, a sync signal, a paging signal and a traffic signal with a first set of orthogonal codes corresponding to orthogonal code numbers in different rows from a set of orthogonal codes arranged in a matrix of m rows and m columns, and channels of the second system for spreading a second set of orthogonal codes corresponding to orthogonal code numbers different from said orthogonal code numbers for the first set of orthogonal codes. The orthogonal codes for the second system are transmitted at a data rate higher than a data rate of the first system.
    Type: Grant
    Filed: December 4, 2000
    Date of Patent: February 21, 2006
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Yu-Suk Yun, Seung-Joo Maeng, Hee-Won Kang, Soon-Young Yoon, Young-Ky Kim
  • Patent number: 7002902
    Abstract: Codes are applied to signals to reduce the number of transceivers and associated RF cabling extending from base electronics to antenna array electronics in a base station providing beam forming. The transceivers can be reduced to as few as one, and the RF cabling can be reduced to none. The codes may be orthogonal codes, such as Walsh codes. The codes are applied: to weights used to produce the beam forming, signal being transmitted or received, or both. The codes are applied a second time to decompose the coded weights/signal to associate the weights and signal with the beam forming. The coded weights/signal can be summed, including with other coded weights/signals, to produce a composite code division multiplexed signal for transmission between transceiver(s) and antenna array electronics over a single RF or non-RF cable spanning between the base electronics and array electronics.
    Type: Grant
    Filed: February 23, 2001
    Date of Patent: February 21, 2006
    Assignee: IPR Licensing, Inc.
    Inventors: James A. Proctor, Jr., Lawrence Wayne LaMont, Jr., George Rodney Nelson, Jr., Antoine J. Rouphael, John E. Hoffmann
  • Patent number: 7002903
    Abstract: A method of verifying that a CDMA code allocator maintains mutual orthogonality between all concurrently busy codes includes the steps of identifying a code being allocated by the allocator, and determining if the identified code is busy. It is also determined if any ancestral parent of the identified code is busy, and if any descendant of the identified code is busy. If the identified code, one of the identified code's ancestral parents, or one of the identified code's descendants is determined to be busy, then an error in allocator operation is indicated.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: February 21, 2006
    Assignee: Lucent Technologies Inc.
    Inventors: Satish Chandra, Patrice I. Godefroid, Christopher D. Palm, Steven M. Welsh
  • Patent number: 6996056
    Abstract: A method and apparatus for enabling Orthogonal codes to be reused within the same cell of a code division multiple access telecommunication network includes an base station transceiver system that comprises logic circuitry for enabling the base station transceiver system to reuse Orthogonal codes in a manner that reduces the likelihood of collision between two mobile stations having the same Orthogonal code and corresponding communication channels.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: February 7, 2006
    Assignee: Nortel Networks Limited
    Inventors: Ashvin H. Chheda, Yiping Wang, Mehmet Yavuz