105 results about "Minimum-shift keying" patented technology

A novel and useful apparatus for and method of Gaussian Minimum Shift Keying (GMSK) single antenna interference cancellation (SAIC) for use in a digital receiver. The invention comprises an interference mitigation module that treats the problem of GMSK SAIC in a blind manner. The interference mitigation mechanism is operative to compensate for the co-channel interference added in the communications channel which is subject to multipath propagation and fading, receiver filter and any pre-channel estimation filtering. The interference mitigation module takes advantage of the spatial diversity making up multiple branches of the received signal. The branches comprise the in-phase and quadrature elements of the received signal, the sampling phases if over sampling is applied (i.e. T/m sampling) and/or multiple antennas. The invention utilizes the spatial diversity of these multiple representations of the received signal and combines (i.e. collapses) the information in the plurality of branches into a single branch that is input to the equalizer.

Systems, apparatus, and methods for new generations of wireless systems, including multiple standard, interoperable Third-Generation (3G) and Second-Generation (2G), Spread Spectrum CDMA, WCDMA, GSM, Enhanced GSM systems and CSMA, TDMA and OFDM. Bit Rate Agile (BRA), Modulation and Code Selectable processing techniques of Gaussian Minimum Shift Keying (GMSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), and of Mis-Matched demodulator filters in which the demodulator filter set is mismatched to the filter set of the signal modulator.

A receiver generates log-likelihood-ratio-based soft bit metrics of precoded quaternary continuous phase modulation signals using four state-constrained trellises and a streamlined maximum likelihood sequence estimation Viterbi algorithm requiring no survivor state storage elements for a preferred error correction-coded quaternary Gaussian minimum shift keying communication system employing reduced-complexity pulse-amplitude modulation matched-filtering and soft-decision decoding.

The invention discloses a connection establishing method, a terminal and an access point (AP). The method comprises the following steps of: sending a first authentication message comprising a user identifier to the AP; receiving a second authentication message which is sent by the AP according to the user identifier and comprises an extensible authentication protocol (EAP) method request message and a site value ANonce of the AP; generating a first pairwise transient key (PTK) according to the ANonce, an SNonce and acquired first minimum shift keying (MSK); sending a third authentication message to the AP, wherein the third authentication message comprises an EAP method response message, the SNonce and first minimal inhibitory concentration (MIC) generated according to the first PTK; receiving a fourth authentication message which is sent by the AP when the first MIC is checked to be correct according to a second PTK, wherein the fourth authentication message comprises an EAP success message, configuration information configured by the AP to the terminal, and second MIC; and checking the second MIC according to the first PTK. By the method, the terminal and the AP of the embodiment of the invention, the interaction number of empty messages can be reduced, and the connection establishment time is shortened, so that electric consumption of the terminal can be reduced, and the user experience is enhanced.

Data aided carrier phase and symbol timing synchronizers are implemented at baseband as digital modulators isolating input signal inphase and quadrature component signals fed into inphase and quadrature Laurent transforms that function as data detector to provide odd and even data bit multiplexed output data signal while cross coupling the inphase and quadrature transformed outputs for removing data modulation in error signals to correct phase errors and timing errors in the received signal so as to provide reliable data demodulation of noisy received signals having dynamic carrier phase and symbol timing errors as found in continuous phase modulation communications systems such as Gaussian minimum shift keying communications systems.

The invention discloses a coherent pseudo code ranging method based on an MSK spread spectrum modulation mode, and relates to the technical field of communication. The method is based on MSK spread spectrum demodulation, a base band ranging pseudo code of a signal is embedded in a communication information code, the ranging is performed at a receiving terminal, two-time coarse ranging and one-time refined ranging are adopted for ranging during the whole process, and a novel filtering mode is adopted during code element synchronization process simultaneously. The method has the benefits as follows: ranging frames are embedded into information frames under the conditions that a communication channel bandwidth is not increased and an original information rate, a spreading code rate and the a MSK modulation mode are not changed, so that long-distance and high-accuracy ranging is realized simply, conveniently and rapidly; the system is operated under the MSK modulation mode and has stronger capacity of resistance to interference and capture; and besides, an improved filtering method is adopted in the code element synchronization method so as to solve the problem of overlarge phase deviation of a bit synchronization pulse, and phase adjustment time is shortened simultaneously.

The invention discloses a multimode multiband radio-frequency onboard micro-micro cellular communication system based on software defined radio, which comprises a receiving module, a local oscillator module, a transmitting module and a control module. The radio-frequency micro-micro cellular communication system can support multiple working bands and working modes: 800-1000 MHz (GMSK (Gaussian Minimum Shift Keying)/CDMA (Code Division Multiple Access) 1X), 2.412-2.472 GHz, and 5.0-5.8 GHz (QPSK (Quadrature Phase Shift Keying)/QAM (Quadrature Amplitude Modulation) 16/OFDM (Orthogonal FrequencyDivision Multiplexing)-QAM 64). In particular environments, such as aircraft flight and the like, the radio-frequency micro-micro cellular communication system can support different radio network services: GSM (Global System for Mobile Communications) (935-960 MHz/890-915 MHz), CDMA (824-849 MHz/869-894 MHz), 802.11b/g (WLAN (Wireless Local Area Network) 2.412-2.472 GHz) and 802.11a (WLAN 5.0-5.8GHz) communication systems. The channel bandwidth varies as the operation mode varies. The maximum bandwidth can reach 20 MHz, the maximum radio-frequency output power is 20 dBm, and the noise factorof the receiving machine is less than 9 dB.

Systems (600) and methods (100) for demodulating a Gaussian Filtered Minimum Shift Keyed (GMSK) signal. The GMSK signal is defined in a transmitted symbol domain where each symbol is given by a product of a current data bit and a previous data bit. The GMSK signal is converted from the transmitted symbol domain to a data symbol domain. The conversion is achieved by approximating filtered complex output signals that would be produced by matched filters having filter shapes corresponding to pulses used in terms of a Laurent expansion. Subsequent to the convention of the GMSK signal, a trellis equalization of the GMSK signal is performed exclusively in the data symbol domain based on the terms of the Laurent expansion.

The invention belongs to the technology filed of wireless communication, relating to a method for jointly demodulating MSK (minimum shift keying) and DSSS (direct sequence spread spectrum) and a demodulator thereof. The demodulator comprises an error information obtaining module, a match filter module, a synchronous information trapping module, a demodulating module and a tracking module; and the method for jointly demodulating MSK and DSSS comprises the following steps of: (1) obtaining error information, (2) matching and filtering the error information, (3) trapping synchronous information, (4) demodulating, (5) tracking, or the like, and sending demodulation results to parent process so as to complete communication process. The invention has the advantage of better frequency compensation ability, thereby, solving the problems that a method for dispreading and demodulating direct sequence spread spectrum signals needs to be frequency offset estimated, complex extraction of PN code synchronization and bit synchronization, etc. Compared with the existing dispreading and demodulating method, the invention is simple as needing no carrier recovery module nor bit timing module, and is applicable to the wireless communication system.

The invention discloses a minimum shift keying/Gaussian Filtered minimum shift keying (MSK/GMSK) direct sequence spread spectrum signal receiver structure; a receiver comprises an antenna, a radio frequency front-end module, an analog-digital converter, a digital baseband module, a signal acquisition tracking control module and a data demodulation module, wherein the antenna outputs a received signal to the radio frequency front-end module; the radio frequency front-end module carries out frequency conversion, amplification and filtration to the received signal; the analog-digital converter converts the processed signal into a digital medium-frequency signal; the digital baseband module acquires and tracks the input signal based on the control of the signal acquisition tracking control module; and the data demodulation module demodulates the acquired and tracked signal. The receiver has the advantages of simple structure and convenience in realization, and is particularly applicable to demodulating data and meanwhile finding range through a spread spectrum signal.

Methods, systems, and devices are described for wireless communication at a UE. A user equipment (UE) may utilize orthogonal frequency division multiple access (OFDMA) for demodulating downlink messages and a combination of Gaussian minimum shift keying (GMSK) and single carrier frequency division multiple access (SC-FDMA) for uplink modulation. The uplink modulation process may include generating a symbol vector with an M-point discrete Fourier transform (DFT), filtering the symbol vector with a frequency domain Gaussian filter, generating a sample vector from the filtered symbol vector utilizing an inverse DFT, and modulating the sample vector utilizing GMSK. In some cases, the uplink modulation may be based on a narrowband resource allocation received from a base station.

User generated and processed Deoxyribose Nucleic Acid (DNA) or fingerprint signal is used for authentication of a mobile device. A touch screen generated processed control signal is used for control of mobile device operated in a cellular system and a Wi-Fi network. The mobile device receives, demodulates and processes a location finder signal and provides processed location finder signal to an interface unit of mobile device. From a cellular base station the mobile device receives, demodulates and processes a modulated spread spectrum signal into a received, demodulated and processed baseband spread spectrum signal and processes, modulates and transmits in cascade the processed spread spectrum signal in a Wi-Fi system. The mobile device operates in a repeater mode. In one of the embodiments the spread spectrum signal uses a Code Division Multiple Access (CDMA) modulated signal and the Wi-Fi system uses OFDM modulated signal. The mobile device comprises step of processing a video signal into baseband in-phase and a quadrature-phase cross-correlated spread spectrum or Time Division Multiple Access (TDMA) signal. The video TDMA signal is modulated and transmitted as a Gaussian Minimum Shift Keying (GMSK) modulated signal in said cellular system and wherein said video signal comprises a three dimensional (3D) image

A method and system for increasing the spectral efficiency of binary coded signals includes encoding an input binary bit sequence such that the input binary bit sequence is converted into a series of rectangular pulses having varying repetition rates. A continuous wave carrier signal is then modulated via a control signal representative of the encoded signal. The modulated optical signal is filtered by a narrow band optical filter to generate a minimum shift keying (MSK) encoded optical signal. In accordance with the present invention, an input binary bit sequence is encoded via a minimum shift keying (MSK) modulation format to improve the spectral efficiency of a binary coded digital signal and to contemporaneously limit distortion of the optical signal induced by optical nonlinear effects during transmission in an optical transmission system.

The invention relates to an improved binary-coded character modulation method of satellite navigation system signals, belonging to the technical field of satellite navigation. On the basis of binary-coded characters, the traditional spread spectrum character is split into K units; each unit uses the character pulse waveform based on MSK (minimum shift keying) instead of the binary value waveform; and proper parameters are selected, thereby having the advantages of interference rejection, multipath resistance and compatibility of the binary-coded character, realizing the constant enveloping of MSK modulation, enhancing the efficiency of the power amplifier, realizing large side lobe attenuation and the like. The invention uses the improved binary-coded character modulation to enhance the code tracking performance, multipath resistance, interference rejection and compatibility with other navigation signals, thereby realizing constant enveloping of signals and avoiding the occurrence of large-amplitude side lobes.

The invention discloses a carrier recovery and clock synchronization method of a GMSK (Gaussian Filtered Minimum Shift Keying) signal capable of rapidly overcoming Doppler shift. The method comprisesthe design of a squaring loop as the main structure of a simple receiver. A phase discriminator module, a loop filter module and a digital voltage controlled oscillator module are included. At the same time, in order to increase the locking speed, the carrier frequency of the GMSK signal is estimated to obtain rough carrier frequency, and then a phase-locked loop is used for locking, thereby effectively shortening the locking time and improves the stability of a locked output signal at the same time. Through adoption of the improved squaring loop structure disclosed by the invention, the accuracy of phase error acquisition is increased, and the phase-locked loop works more stably. The method is applied to the fields of spaceflight test control and deep space communication, and can well meet the communication demand standard.

The invention relates to an FSK receiver for MSK capable of transmitting an MSK-modulated signal via FSK demodulation, and a method for setting a plurality of reference PN sequences thereof. In the FSK receiver for MSK of the invention, an RF converter converts an MSK-modulated RF signal into an IF signal. An FSK receiver FSK-demodulates the IF signal into a chip signal. Also, a correlation array includes an FSK PN sequence table comprising a plurality of reference PN sequences having a plurality of FSK reference chip signals. The correlation array collects the chip signal from the FSK receiver to generate a plurality of PN sequences having a plurality of chip signals, and correlating the generated PN sequences with each of the reference PN sequences to restore raw data. The invention provides the method for setting the plurality of FSK reference PN sequences in the FSK receiver for MSK.

The invention discloses a constant-envelop (CE) light OFDM-MSK (orthogonal frequency division multiplexing-minimum shift keying) modulation method, which is capable of minimizing PAPR (peak to average power ratio) and dropping the border of the frequency spectrum quickly so as to reduce interference among carrier waves, enhances resistance capability of the light OFDM system to interference of nonlinearity and subcarriers and accordingly improves the performances of long-distance large-capacity light OFDM transmission system. The modulation method includes the following steps: (1) a transmitting end generates OFDM-MSK signals; (2) the signals generated in the step (1) are subjected to digital-to-analogue conversion and optical phase modulation so as to generate CE-OFDM-MSK light signals to be sent to optical fibers; (3) a receiving end receives the CE-OFDM-MSK light signals by means of relative detection and the CE-OFDM-MSK light signals are subjected to phase modulation to be OFDM-MSK signals; and (4) source end data are acquired by means of modulation reverse to the modulation process of generating the OFDM-MSK signals.

The invention relates to a cascade-mode-based quaternary minimum-shift keying (MSK) modulation method and a cascade-mode-based quaternary MSK modulation device. A modulator comprises a first serial parallel converter and a second serial parallel converter; a demodulator comprises a 2FSK (frequency shift keying) modulation module and a 2MSK modulation module; the upper braches of the first serial parallel converter are connected with the second serial parallel converter by an EOR (exclusive OR) arithmetic unit and a differential coder in turn; the lower braches of the first serial parallel converter are connected with the input end of the 2MSK modulation module through the 2FSK modulation module and a band-pass filter in turn; the upper branch of the second serial parallel converter is connected with the cophase component end of the 2MSK modulation module through a delayer; the lower branch of the second serial parallel converter is connected with the orthogonal component end of the 2MSK modulation module; the output end of the 2MSK modulation module is connected with the band-pass filter; and the lower branch of the first serial parallel converter is connected with the EOR arithmetic unit. Due to the adoption of the method and the structure, quaternary MSK signals, which have constant envelope, continuous phases, minimum bandwidth and strict orthogonality, can be provided.

The invention relates to a 230 MHz wireless communication speed self-adaptive designed-to-change collection terminal. A signal output/input end of an interface unit is correspondingly connected with a first signal input/output end of an adapter plate, the signal output/input end of a processing and displaying unit is correspondingly connected with a second signal input/output end of the adapter plate, the signal output/input end of a communication unit is correspondingly connected with a third signal input/output end of the adapter plate, and a power supply output end is connected with power supply input ends of the adapter plate, the communication unit, the processing and displaying unit and the interface unit. The 230 MHz wireless communication speed self-adaptive designed-to-change collection terminal disclosed by the invention has the advantages of having a 230 HMz private network channel with three different speed and modulation modes of 2400bps-MSK (Minimum Shift Keying), 9600bps-GMSK (Gaussian Filtered Minimum Shift Keying) and 19200bps-4FSK (Frequency Shift Keying), different systems and field conditions can be adapted, and a GPRS (General Packet Radio Service) or CDMA (Code Division Multiple Access) public network channel can be used for logging in and operating through the issuing or the manual setting of a main station when the 230 HMz private network channel is not in existence or a public network channel needs to be used.