Signal-to-noise Ratio Patents (Class 455/226.3)
  • Publication number: 20030022648
    Abstract: A combiner for a diversity radio receiver wherein amplitude inversion of either received signal is performed, on a selection basis, in order to maximize the resultant output combined signal. The strength of each diversity signal is monitored as well as the strength of the combined output signal. A gain control engine combines the stronger signal with either the inverted or non-inverted weaker signal to maximize the combined output (resultant) signal strength. According to another embodiment the combiner may additionally perform an amplitude adjustment whereby the in-channel noise power is also monitored and the individual channel signal-to-noise ratios are used to adjust the amplifier gains. In this embodiment the individual channel signal-to-noise ratios plus the strength of the combined output signal are used to decide whether to invert the weaker signal before combining the received signals.
    Type: Application
    Filed: February 6, 2002
    Publication date: January 30, 2003
    Applicant: J.S. Wight, Inc.
    Inventor: James Stuart Wight
  • Patent number: 6507622
    Abstract: To use high noise transmission lines, such as an electric wire, as the lines to transmit signals, it is imperative to reduce the level of signals. The present invention is provided with a sending signal generating means 10, which outputs converted data after converting an input signal into a plurality of carrier signals assuming values at such intervals on the axis of frequency that the frequencies may not interfere with each other. If an interfering noise with any one of the plurality of frequencies arises on the transmission line, removal of only a carrier of the noise frequency would leave the communication in a good condition.
    Type: Grant
    Filed: September 23, 1998
    Date of Patent: January 14, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masahiro Maki, Shoichi Koga, Satoshi Shinozaki, Yuji Igata, Satoshi Hasako, Michinori Kishimoto, Kazuhiko Tamesue
  • Patent number: 6504867
    Abstract: A digital radio tuner signal estimator receives a digitized in-phase (I) data signal and a digitized quadrature (Q) data signal and provides an estimated amplitude gain signal and an estimated signal-to-noise ratio signal value. The signal estimator includes a symmetrical matched I data digital filter having a first I filter section that filters the received I data signal and provides a first I data signal, and a second I filter section that filters the I data signal and provides a second I data signal. The signal estimator also includes a symmetrical matched Q data digital filter having a first Q filter section that filters the received Q data signal and provides a first Q data signal, and a second Q filter section that filters the Q data signal and provides a second Q data signal. The first and second I data signals and the first and second Q data signals are processed to compute an estimated amplitude gain.
    Type: Grant
    Filed: March 26, 1999
    Date of Patent: January 7, 2003
    Assignee: Analog Devices, Inc.
    Inventor: Dimitrios Efstathiou
  • Patent number: 6473451
    Abstract: The invention provides a technique for measurement of a signal to interference power ratio wherein an SIR can be measured with a higher degree of accuracy without being influenced by a fast fading environment or an inter-station interference or noise environment.
    Type: Grant
    Filed: January 4, 2000
    Date of Patent: October 29, 2002
    Assignee: Fujitsu Limited
    Inventors: Hiroyuki Seki, Yoshinori Tanaka, Shuji Kobayakawa, Takeshi Toda, Masafumi Tsutsui
  • Publication number: 20020151286
    Abstract: The invention relates to a method for supplying reference data that is to be used in a mobile station of a radio communications network for a frequency update of the frequency used by the mobile station, which reference data is based on bursts received by the mobile station from a base station of said radio communications system. In order to allow for an improved supply of reference data to an automatic frequency correction algorithm, it is proposed that the method comprises determining the signal-to-noise-ratio of all bursts received unless they were discarded by some selection process; and providing at least some of the bursts for which a signal-to-noise-ratio greater than a predetermined value was determined as basis for the reference data to be used for the frequency update. The invention equally relates to a mobile station, a module and a radio communications system comprising the corresponding means.
    Type: Application
    Filed: February 25, 2002
    Publication date: October 17, 2002
    Inventors: Jari Ruohonen, Nils Degn, Timo Harkala, Jarkko Oksala
  • Patent number: 6466137
    Abstract: A receiver/controller unit (14) of a remote convenience system (10) receives an electromagnetic signal (18). The signal (18) is comprised of a plurality of pulses that convey a remote convenience function request. In response to the receipt of the signal (18), the receiver/controller unit (14) causes performance of the requested function. The receiver/controller unit (14) has a comparator (82). A first input of the comparator (82) is connected to receive an electrical signal (78) with an electrical characteristic that varies to convey the remote convenience function request. A second input of the comparator (82) is connected to receive a signal 86 that has a threshold electrical characteristic value. Preferably, the electrical characteristic is voltage amplitude. An output of the comparator (82) provides a signal indicative of the occurrence of the electrical characteristic of the electrical signal (78) exceeding the threshold value, and that conveys the remote convenience function request.
    Type: Grant
    Filed: February 23, 1999
    Date of Patent: October 15, 2002
    Assignee: TRW Inc.
    Inventors: Xing Ping Lin, Kurt Alan Perski
  • Patent number: 6453156
    Abstract: A method for use in a receiver in a time division multiple access (TDMA) wireless communication system to determine whether a channel is occupied and whether the transmitter occupying the channel is internal or external to the system. The method comprises the steps of receiving a signal, on a channel determining that the channel is unoccupied when the signal strength of the channel signal is below a threshold, determining that the transmitter is internal to the system when the received signal is highly correlated to a signal that is known to contain the proper predefined field.
    Type: Grant
    Filed: September 24, 1998
    Date of Patent: September 17, 2002
    Assignee: Ericsson Inc.
    Inventors: Stephen Douglas Center, Yngve Kenneth Wallstedt
  • Patent number: 6438362
    Abstract: A method for measuring characteristics of a propagated radio-wave on the basis of a reference signal, wherein the reference signal is obtained by receiving and demodulating the propagated radio-wave, comprising the steps of: estimating characteristics of a propagation-path, through which the radio-wave has been transmitted, on the basis of the reference signal; determining a desired-signal power and an interference-signal power of the propagated radio-wave on the basis of the estimated characteristics: and deriving an SIR by performing calculations on the desired-signal power and the interference-signal power.
    Type: Grant
    Filed: February 22, 1999
    Date of Patent: August 20, 2002
    Assignee: Oki Electric Industry CO, Ltd.
    Inventor: Yasuharu Amezawa
  • Publication number: 20020111143
    Abstract: This invention discloses a baseband processing method based on smart antenna and interference cancellation. The method includes the steps of: A. making a channel estimation to get a channel response; B. picking up useful symbolic level signals from received digital signals by smart antenna beam forming based on the channel estimation of step A; C. reconstructing the useful symbolic level signals and adding a scrambling code to get the chip level reconstructed signal; D. subtracting the reconstructed signal from the received digital signal; and E. executing steps B to D repeatedly to recover signals for all users. The method of the invention can solve problems associated with interference of multi-path propagation in CDMA systems with smart antennas with better results.
    Type: Application
    Filed: February 11, 2002
    Publication date: August 15, 2002
    Applicant: China Academy of Telecommunications Technology
    Inventor: Feng Li
  • Patent number: 6430237
    Abstract: An interference measurement technique in for example a wireless receiver uses a received, unprocessed signal and correlates it with a signal reconstructed from detected information, then compares a square of the correlated signal with a square of the received signal to produce a signal-to-interference metric useful for evaluating a channel quality, such as in a wireless telecommunication environment.
    Type: Grant
    Filed: November 16, 1998
    Date of Patent: August 6, 2002
    Assignee: Transamerica Business Credit Corporation
    Inventor: Kiomars Anvari
  • Patent number: 6421527
    Abstract: A system for dynamic adaptation of wireless communication between a Mobile Station (11) and a Base Station (13) wherein the transmitted frame from the Mobile Station includes a convolutionally coded portion containing a down-link measurement bit and a repetition code identifying the codec mode of the frame. The transmitted frame from the Base Station (13) includes a codec mode command signal for the Mobile Station (11) in the convolutionally encoded portion and the repetition code identify the codec mode of the down-link frame. The Base Station (13) includes means for analyzing the quality of the up-link frame and means from the received down-link measurement bit for determining the down-link quality.
    Type: Grant
    Filed: May 13, 1999
    Date of Patent: July 16, 2002
    Assignee: Texas Instruments Incorporated
    Inventors: Juan-Carlos DeMartin, Alan V. McCree, Krishnasamy Anandakumar
  • Publication number: 20020052186
    Abstract: Low swing communication system wherein the output driver's signal is used to adjust the driver's swing to the receiver's parameters, in particular, the hysteresis at the receiver. The receiver generates a signal indicative of parameters bearing information on the maximum and minimum levels, e.g. voltage, current or other levels, to cause a signal to be received as a logical one and as a logical zero. This parameter signal may be digital, but is preferably a differential analogue signal. The parameters influence the signal swing of the driver.
    Type: Application
    Filed: November 6, 2001
    Publication date: May 2, 2002
    Inventors: Alexander Roger Deas, Vasily Grigorievich Atyunin
  • Patent number: 6363245
    Abstract: A favorable communication state is set when communication different from a telephone conversation such as data communication and the like is carried out. A control unit (32) judges a reception situation detected by a reception situation detecting unit in comparison with a first threshold value and judges the same in comparison with a second threshold value. The reception situation based on the comparison with the first threshold value and the reception situation based on the comparison with the second threshold value in the control unit are notified of by respectively different notifying units (35) and (36).
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: March 26, 2002
    Assignee: Sony Corporation
    Inventor: Makoto Natori
  • Publication number: 20020016157
    Abstract: A method and system for detecting satellite signal lock in a satellite receiver system is disclosed. The system includes a first filter that isolates a noise frequency from the satellite signal, a second filter that isolates a service frequency from the satellite signal, circuits that derive a value indicative of the difference between a noise component and a service frequency component and output a difference signal level, a first comparator that determines whether the difference signal level is greater than a first threshold level, and a second comparator that determines whether the difference signal level is greater than a second threshold level.
    Type: Application
    Filed: May 10, 2001
    Publication date: February 7, 2002
    Applicant: Hughes Electronics Corporation
    Inventors: Robert G. Arsenault, Patrick J. Loner
  • Patent number: 6343210
    Abstract: A method and apparatus for soft decision propagation trades off system bandwidth in return for link margin. When signal quality on an uplink is low, a satellite (20) sends soft decision data, rather than hard decision data, to a gateway (40). When path diversity exists on the uplinks, and multiple satellites (20) receive the uplink, multiple versions of soft decision data are sent to the gateway (40). The gateway combines the soft decision data resulting from multiple uplink paths, thereby increasing the effective uplink signal to noise ratio.
    Type: Grant
    Filed: March 22, 1999
    Date of Patent: January 29, 2002
    Assignee: Motorola, Inc.
    Inventors: Thomas Peter Emmons, Jr., Robert Anthony Peters, James W. Startup
  • Publication number: 20010056331
    Abstract: The invention concerns a procedure for determining the signal-to-noise ratio (&rgr;) of a signal (y) with wanted signal components (x) and noise signal components (n), it being assumed that the noise signal components (n) have a Gaussian distribution. In order that the signal-to-noise ratio of the signal (y) can be calculated in an accurate and reliable manner, including, in particular, when there are only relatively few measurement values (S) per measurement interval or when there is only a relatively poor signal (y) with a high noise signal component (n), it is proposed that the signal (y) be manipulated, before the signal-to-noise ratio (&rgr;) is determined, in such a way that the noise signal components (n) have a greater probability of having a Gaussian distribution. It is proposed, according to a development, that a noise signal (n′) with a known power be added to the signal (y). The noise signal (n′) preferably has a Gaussian distribution.
    Type: Application
    Filed: May 11, 2001
    Publication date: December 27, 2001
    Applicant: ALCATEL
    Inventors: Kang Lu, Rolf Matzner, Witthaya Panyaworayan
  • Patent number: 6330431
    Abstract: A method is described of measuring the burst quality of a received signal. Specifically, the impairment correlation matrix, used to provide an estimate of impairment correlation properties for use in demodulating radio signals received by a plurality of antennas, is used to obtain the parameters necessary to obtain measurements of the burst quality, with respect to the signal to noise ratio and the signal to interferer ratio respectively. Specific algorithms for calculating the burst quality are also disclosed.
    Type: Grant
    Filed: July 8, 1998
    Date of Patent: December 11, 2001
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Jafar Rostamy, Peter Wahlström
  • Patent number: 6330432
    Abstract: SIR (signal to impairment power ratio) of a received signal in a communications system is determined from DC components produced by at least two successive stages of performing a non-linear operation, e.g. squaring, the signal and separating the DC component from a non-DC component for supply to the next stage. A signal power of a desired signal component of the received signal can also be determined from the DC components. The signal power can be auto-correlated, and normalized auto-correlation results which exceed a threshold can be used to determine a Doppler bandwidth of the received signal, which can be used to adaptively adjust filters used for separating the DC components.
    Type: Grant
    Filed: July 16, 1998
    Date of Patent: December 11, 2001
    Assignee: Nortel Networks Limited
    Inventors: Wen Tong, Rui Wang, Eddy Ning Hum
  • Patent number: 6317600
    Abstract: The invention relates to a method for load control and a radio system. In the invention a load result describing the load is cell-specifically formed. The load result is formed either by comparing a signal strength of desired signals (23) and a combined total strength of interferences (13) and the desired signals (23) or by weighting a signal-to-interference ration with a bandwidth or a data transmission rate. The load result is compared with a threshold value of the highest load level allowed of a cell (1). The data transmission rate in the cell (1) is increased if the load result is smaller than the threshold value. The data transmission rate in the cell (1) is reduced and the establishment of new connections is avoided if the load result exceeds the threshold value. In heavy load situations a signal-to-interference objective is also changed in order to balance the load result.
    Type: Grant
    Filed: October 8, 1998
    Date of Patent: November 13, 2001
    Assignee: Nokia Telecommunications Oy
    Inventors: Oscar Salonaho, Hannu Häkkinen, Seppo Granlund
  • Patent number: 6285887
    Abstract: A transmission power control system in code division multiple access (CDMA) system, which makes possible to control an aimed SIR, which is compared with a measured SIR for the transmission power control, in order to maintain all channels to be an optimum communication quality even when there is a difference in communication quality in each channel in a multi-code transmission, is realized. The transmission power control system comprises at least one base station and a base station control apparatus. The base station measures the signal to interference ratio (SIR) of a received signal corresponding to each of a plurality of channels established between the base station and a mobile station, and determines a bit pattern for transmission power control for each of groups specified to the plurality of channels on the basis of the aimed SIR and the measured SIR.
    Type: Grant
    Filed: September 15, 1999
    Date of Patent: September 4, 2001
    Assignee: NEC Corporation
    Inventor: Yukie Mimura
  • Patent number: 6236838
    Abstract: A system for wireless communication between a base station 30 and one or more remote stations 32 and 34 wherein a desired signal has associated therewith an identifier tone (a SAT in the vernacular of the AMPS system) and wherein interfering signals may have associated therewith identifier tones at different frequencies. A superresolution technique is used in the system to process the received data and to determine the relative magnitudes of any identifier tones which may be present in the received data. In the disclosed embodiment, the superresolution technique utilized is a least square error process. The resulting estimates are used by the system to facilitate the communication function.
    Type: Grant
    Filed: June 3, 1997
    Date of Patent: May 22, 2001
    Assignee: Texas Instruments Incorporated
    Inventors: William P. Golemon, Henry S. Eilts
  • Patent number: 6233274
    Abstract: Method and apparatus for non-invasive testing of digital communications systems. Amplitude measurements are made for multiple frequencies of a multi-frequency communication system, converted to the time domain. An adaptive filter output is matched to the time domain representation to characterize the channel. Impedance mismatches may be precisely located using this technique. An error signal representing a difference between a signal transmitted through the channel and a received signal is estimated and analyzed. The error signal is separated into components corresponding to contributions by wide band noise, residual phase modulation, and residual amplitude modulation. Identification and removal of narrow-band interferers may occur prior to this separation. Bit error rate and system margin computations employ a Monte Carlo simulation of the various error sources. This provides a well refined estimate of bit error rate and system margin.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: May 15, 2001
    Assignee: Wavetek Wandel Goltermann
    Inventors: Ernest T. Tsui, Jeffrey Marc Kletsky
  • Patent number: 6181739
    Abstract: Methods and systems for measuring signal noise of supervisory audio tones (SATs) in radiocommunication systems are disclosed. Exemplary embodiments involve extracting a real component from a received SAT signal, removing the SAT signal portion and examining the remainder to determine a noise component present in the SAT. The noise component can be compared with a signal strength measurement to obtain a signal-to-noise ratio.
    Type: Grant
    Filed: November 22, 1995
    Date of Patent: January 30, 2001
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Omar Ryde, Olof Tomas Backström, Lars Peter Wahlström