Abstract: An embodiment of a method for decoding a received signal function of at least a channel matrix B, and of a first and second symbols S1, and S2 belonging to a signal constellation. The method comprises the steps of: selecting a set of values of the first symbol S1 in the signal constellation; for each selected value of the first symbol S1: estimating the value of the second symbol S2 to generate an estimated value of the second symbol; calculating an Euclidean distance between the received signal and a noiseless signal defined by the first symbol with said selected value and by the second symbol with said estimated value; selecting the minimal Euclidean distance among the Euclidean distances respectively calculated for the different selected values of the set of possible values of the first symbol; and selecting decoded first and second symbols corresponding to the selected minimum Euclidean distance.
Abstract: An embodiment of a method for transmitting a sequence of symbols through at least a channel in a wireless communication system comprises at least the steps of: forming a coding matrix (MC) with said sequence of symbols, each component of the coding matrix (MC) being a linear combination of two symbols among a first, a second, a third, and a fourth symbol (s1, s2, s3, s4), transmitting a first and a second components of a first column and of a second column of the coding matrix through a first and a second transmit antennas (Tx1, Tx2), at a first and a second time slot (T1, T2). The coding matrix (MC) is defined as: ( as 1 + bs 3 - cs 2 * - ds 4 * as 2 + bs 4 cs 1 * + ds 3 * ) , a, b, c, d being complex numbers of modulus 1.
Abstract: A method is provided for transmitting radio signals. Two channels are defined by two transmit antennas, having two orthogonal directions, together with two receive antennas, having two orthogonal directions. An optimal quality of one received signal is determined by signal processing, which emulates a rotation of the two orthogonal receive directions, and a mutual interference of the signals received on the two channels, due to a polarization mismatch, is cancelled, based on a corresponding optimal rotation angle.
Abstract: A method of synchronizing a base station of a wireless communication system and a subscriber communication equipment located in the coverage area of the base station by compensating a sampling frequency offset in the subscriber equipment by interpolating input and/or output signals of a radio frequency part of the communication equipment to generate samples corresponding to the original symbol timing of the base station, and compensating the carrier frequency offset from the estimate of the sampling clock error.
Abstract: An embodiment of a method for transmitting data through at least a channel in a wireless communication system, the method comprising at least the steps of: encoding the data by performing a forward-error-correction encoding, forming a sequence of symbols from the encoded data, forming an M-by-T coding matrix from said sequence of symbols, each column of the coding matrix comprising N different symbols of the sequence of symbols and M?N zeros, N being an integer equal at least to one, T representing the number of consecutive transmission intervals, M representing the total number of transmit antennas, and using the coding matrix for transmitting the sequence of symbols during the T consecutive transmission intervals, by transmitting one different column of the coding matrix at each transmission interval through the M transmit antennas, only N transmit antennas are enabled during a given transmission interval.
Type:
Application
Filed:
June 22, 2009
Publication date:
December 24, 2009
Applicant:
SEQUANS COMMUNICATIONS
Inventors:
Fabien BUDA, Bertrand MUQUET, Serdar SEZGINER
Abstract: A method is provided for channel scanning in a wireless communications system, for the identification of one or more narrow-band channels present in a certain frequency band and which can be used for connection between a wireless communications device and a communications network. The method includes: applying a FFT function to at least one signal corresponding to a given frequency band, providing for a set of coefficients each being representative of a frequency, analyzing the coefficients so as to detect at least one frequency region having at least one predetermined feature, and determining at least one channel position, by considering that each of the at least one frequency region having at least one predetermined feature is a guard band of one of the at least one channel.
Abstract: A method and apparatus are provided for radio access technology (RAT) monitoring, in a wireless system environment having wireless communications equipment and at least two different RATs that coexist for providing to the equipment access to one or more communications networks. The equipment has at least two subsystems, each adapted for establishing and maintaining an active communications connection with a certain one of the different RATs. The equipment selects at least a first RAT, among all the RATs available in a certain geographical area, for establishing the active communications connection, according to a monitored characteristic of the first RAT. The method includes scanning a characteristic of a second RAT available for communication in the geographical area while the equipment maintains an active communications connection with the first RAT, and performing the scanning step when the equipment does not transmit signals through the active communications connection maintained with the first RAT.
Abstract: A peak power reduction method for wireless communication systems is proposed in which a constellation shaping is applied on input data symbols in order to reduce the peak power of the signal samples to be transmitted by the communication system. According to the invention, the symbols are modified using functions each representing the contribution of a symbol to the output signal samples of large magnitude.
Abstract: An embodiment of a method for controlling the interference level generated by a mobile station comprising at least steps: selecting at least one neighbor base station; estimating a first attenuation value between the mobile station and a current base station, and at least a second attenuation value between the mobile station and the neighbor base station; estimating an interference level: I_level=BS0—RSS+L0?L, BS0_RSS being a first received signal strength at the base station, from the mobile station, L0 being the first attenuation value, and L being one second attenuation value estimated in step B, comparing the interference level to a reference interference level, and according to the result of the comparison, sending to the mobile station at least information relative to a maximum transmitted signal strength.
Abstract: A method is provided for memory management in a communications system using a HARQ error control mechanism, in which a transmitter establishes a plurality of HARQ channels with a receiver. The method includes determining whether each received encoded HARQ packet needs to be combined with an encoded HARQ packet already stored in HARQ memory. In case a received encoded HARQ packet does not need to be combined, the method determines whether there is a free memory space available in the HARQ memory for storing that received encoded HARQ packet, and if so, allocating that free memory space for storage of that received encoded HARQ packet. If not, the method determines whether a certain amount of memory space can be forced to be freed, and if so, de-allocates it and then allocates it for storage of that received encoded HARQ packet, that packet is sent to an FEC decoder.
Abstract: A gain-controlled RF amplifier system has an input node and an output node. The system has a plurality of amplifier devices, selectively connectable between the input node and the output node. The amplifier devices are placed in circuit according to a measured gain derived by comparing a magnitude of a signal input to the input node against a magnitude of a signal output from the output node, and a desired value of gain.
Abstract: An embodiment of a method for switching to an operating mode a device comprising a counter counting the pulses number of a first clock and a date synchronized with an external reference date. The embodiment comprising at least: step A: at a first pulse edge of the first clock, storing corresponding first pulses number and first date synchronized with a first reference date; step B: at a second pulse edge of the first clock, storing corresponding second pulses number and second date synchronized with a second reference date; step C: computing a frequency error of the first clock by using at least the values stored; step D: according to the frequency error, computing a third pulses number; and step E: switching the device to the second operating mode at the occurrence of the third pulses number.
Abstract: An embodiment of a device for processing at least an incoming signal in a wireless communication system, said incoming signal being sent by a base station and comprising successive frames, each of which comprising at least a training symbol correlated to said base station, and a data symbol carrying message data. The device comprises at least: a first module digitizing and sampling the incoming signal; a second module demodulating said digitized and sampled incoming signal, and generating a corresponding frequency domain symbol; a timing synchronization and scanning module suitable for detecting at least a time offset of said training symbol by using said corresponding frequency domain symbol; and a timing post processing module for processing said timing offset and for generating an improved timing offset used to start the sampling of following incoming signal.