Patent application number | Description | Published |
20080232496 | Device and method for compensating timing offset - A method and OFDM receiver for estimating timing offset. The method comprises the method of receiving OFDM data to calculate frequency offset between a transmitter carrier frequency and a receiver carrier frequency, the method of determining first timing offset based on the frequency offset, the method of compensating the OFDM data with the first timing offset, the method of estimating a residual common phase based on the compensated OFDM data, the method of determining second timing offset based on the residual common phase, and the method of compensating the OFDM data with the second timing offset, if the frame symbol index exceeds the predetermined data length. | 09-25-2008 |
20080260076 | CARRIER FREQUENCY OFFSET ESTIMATION METHOD AND SYSTEM - In one aspect of the invention, a carrier frequency offset (CFO) estimation method to estimate a CFO value of a received signal is provided, and the method comprises: receiving a preamble signal which includes several non-perfect repeat segments; applying an interpolation procedure to interpolate the perfect repeat point of one segment compared with the next segment or the previous segment; acquiring a delay correlation value based on the two perfect repeat signal segments and estimating the CFO value based on the delay correlation value. | 10-23-2008 |
20080260085 | Method and device for estimating integer carrier frequency offset - The method disclosed in the invention comprises setting a plurality of subcarrier position hypotheses for a received preamble according to a plurality of ideal subcarrier positions and the maximum amount of integer carrier frequency offset (ICFO), generating a plurality of preamble pattern hypotheses by retrieving the received preamble according to the subcarrier position hypotheses, calculating the correlation between the preamble pattern hypotheses and a plurality of specified preamble patterns, determining to which sector the received preamble belongs according to a correct preamble pattern, the specified preamble pattern having the highest correlation with the preamble pattern hypotheses, obtaining a correct subcarrier position according to the sector to which the received preamble belongs; and estimating the ICFO by calculating the offset between the correct subcarrier position and the subcarrier position hypothesis of the preamble pattern hypothesis having the highest correlation with the correct preamble pattern. | 10-23-2008 |
20080279221 | Method for estimating and compensating IQ imbalance in OFDM systems - A method for compensating IQ imbalance is disclosed. First, an OFDM signal is received. The OFDM signal is translated into frequency domain, wherein the translated OFDM signal has N sub-carriers noted as Y(1)-Y(N). The IQ imbalance compensation factor is generated according to the k-th sub-carrier of the translated signal Y(k), the (N−k+2)-th sub-carrier of the translated signal Y(N−k+2), and the complex conjugates thereof. | 11-13-2008 |
20080310525 | FFT-size detector and FFT-size detection method and cell search apparatus and cell search method in cellular system - An apparatus and method for cell acquisition and downlink synchronization acquisition in an OFDMA wireless communication system are provided. In an SS apparatus in a broadband wireless communication system, a preamble subcarrier acquirer extracts subcarrier values having a preamble code from an FFT signal. A multiplier code-demodulates the subcarrier values by multiplying the subcarrier values by a preamble code. A correlator calculates a plurality of differential correlations in the code-demodulated signal. An IFFT processor IFFT-processes the differential correlations by mapping the differential correlations to subcarriers. A maximum value detector detects a maximum value from the IFFT signal and calculates a timing offset using an IFFT output index having the maximum value. | 12-18-2008 |
20090041161 | DC offset estimation system and method - A DC offset estimation system is disclosed. A DC offset estimation system includes a carrier frequency offset estimator receiving an input signal and estimating a carrier frequency offset value, a symbol timing recovery unit providing a symbol boundary of the input signal, and a DC offset estimator estimating a DC offset value to compensate the input signal based on the input signal, the carrier frequency offset value, and the symbol boundary. | 02-12-2009 |
20090161800 | METHOD AND APPARATUS FOR PACKET DETECTION - A present invention provides a method and an apparatus for packet detection. The packet detection method with adaptive strategy includes several stages, and each stage has different parameter setting for packet detection. The method provides the packet detection apparatus with adaptive advantage to adapt various channel environments. The method and an apparatus for packet detection can effectively promote the success probability to detect packets. | 06-25-2009 |
20100014606 | SYMBOL DETECTOR AND SPHERE DECODING METHOD - A symbol detector with a sphere decoding method implemented therein. A baseband signal is received to determine a maximum likelihood solution using the sphere decoding algorithm. A QR decomposer performs a QR decomposition process on a channel response matrix to generate a Q matrix and an R matrix. A matrix transformer generates an inner product matrix of the Q matrix and the received signal. A scheduler reorganizes a search tree, and takes a search mission apart into a plurality of independent branch missions, wherein the search tree defines a full search depth N | 01-21-2010 |
20100027703 | MULTIPLE-INPUT MULTIPLE-OUTPUT DETECTOR AND DETECTION METHOD USING THE SAME - A multiple-input multiple-output detector and a detection method using the same are provided. The detection method includes following steps. First, a plurality of candidate results is provided by a plurality of detectors. Next, a channel condition and a detected criterion are provided. Finally, one of the candidate results is selected to serve as a detected result according to the channel condition and the selection criterion. | 02-04-2010 |
20100061318 | CHANNEL SCAN METHOD AND ARCHITECTURE FOR WIRELESS COMMUNICATION SYSTEMS - In wireless communication system and method, a guard band detection (GBD) is performed in a channel to detect the existence of guard bands of a correct channel, so to predetermine that whether the current channel is correct or not. If GBD and a subsequent authorization are both passed in the channel, then the channel is determined as the correct channel. Besides, multiple point estimation (MPE) can be used to analyze the signal strengths in different frequencies to predict the location of the correct channel. | 03-11-2010 |
20100104053 | APPARATUS AND METHOD FOR ESTIMATING INTER-CARRIER INTERFERENCE POWER AND NOISE POWER IN A CHANNEL - An estimation method is provided for use in a receiver of an OFDM (orthogonal frequency division multiplexing) system to estimate the ICI (inter-carrier interference) and the noise power of a channel. Two pilot signals respectively carried by two subcarriers are received from the channel wherein the two pilot signals are adjacent and differ by a first phase angle. Another two pilot signals respectively carried by another two subcarrier are received from the channel wherein the another two pilot signals are adjacent and differ by a second phase angle. According to some embodiments of the invention, these phases are correlated with the ICI power, but are uncorrelated with the noise power. The estimation method then individually estimates the ICI power and noise power according to the first phase and the second phase. | 04-29-2010 |
20100303167 | HIERARCHICAL MODULATION SYSTEM AND TRANSMITTER AND METHOD THEREOF - An exemplary embodiment of the present invention proposes a transmitter including a hierarchical modulator. The hierarchical modulator receives, jointed encodes, and maps a high-priority and low-priority bit-stream signals, so as to generate multiple mapping signal, wherein each mapping signal is the summation of a low-priority and high-priority mapping signals. The low-priority mapping signal is the complex number signal on the frequency domain to which part bits of the low-priority bit-stream signal are mapped, and the high-priority mapping signal is the complex number signal on the frequency domain to which part bits of the high-priority bit-stream signal are mapped. The p | 12-02-2010 |
20110013735 | PROGRESSIVE PARALLEL INTERFERENCE CANCELLER AND METHOD AND RECEIVER THEREOF - A progressive parallel interference canceller (PPIC) and a method and a receiver thereof are illustrated. The PPIC reconstructs each subchannel interference reconstruction signal through several iterations and subtracts the corresponding subchannel interference reconstruction signal from each subchannel frequency-domain reception signal to obtain a subchannel frequency-domain signal. Thereby, according to the present disclosure, inter-channel interference can be cancelled without re-performing channel coding or estimating the signal to noise ratio (SNR) or frequency offset. | 01-20-2011 |
20110038433 | CODEBOOK SEARCHING APPARATUS AND METHOD THEREOF - Exemplary embodiments of the present disclosure propose multiple codebook searching methods for a receiver in a communication system, wherein the communication system uses a codebook having L pre-coding matrices. First, L matrices are calculated according to the L pre-coding matrices, and the L matrices are inversed mean square error matrices of the L pre-encoding matrices. Then, diagonal cofactors or determinants of at least S matrices of the L matrices are calculated, and a pre-coding matrix used by the receiver is found according to the maximum cofactors of the diagonal of the at least S matrices or ratios between the maximum cofactors of the diagonals and the determinants of the at least S matrices. | 02-17-2011 |
20110164568 | FFT-SIZE DETECTOR AND FFT-SIZE DETECTION METHOD AND CELL SEARCH APPARATUS AND CELL SEARCH METHOD IN CELLULAR SYSTEM - An apparatus and method for cell acquisition and downlink synchronization acquisition in an OFDMA wireless communication system are provided. In an SS apparatus in a broadband wireless communication system, a preamble subcarrier acquirer extracts subcarrier values having a preamble code from an FFT signal. A multiplier code-demodulates the subcarrier values by multiplying the subcarrier values by a preamble code. A correlator calculates a plurality of differential correlations in the code-demodulated signal. An IFFT processor IFFT-processes the differential correlations by mapping the differential correlations to subcarriers. A maximum value detector detects a maximum value from the IFFT signal and calculates a timing offset using an IFFT output index having the maximum value. | 07-07-2011 |
20110261908 | SOFT DEMAPPING METHOD AND APPARATUS AND COMMUNICATION SYSTEM THEREOF - An exemplary embodiment of the present disclosure provides a soft demapping method. In the soft demapping method, each shortest Euclidean distance of the Euclidean distances from all possible signal vectors corresponding to the bits which are not obtained during a signal detection to a received signal vector is calculated by using channel state information (CSI) and modulation coefficients, so as to establish a complete bit vector-shortest distance mapping table, and a log likelihood ratio (LLR) of each bit is obtained according to the bit vector-shortest distance mapping table. The soft demapping method can be applied along with different signal detection techniques to decode a received signal vector into a bit vector, wherein the signal detection techniques include a maximum likelihood detection (MLD) technique and a sphere decoding (SD) technique. | 10-27-2011 |
20120030203 | METHOD FOR ESTABLISHING MULTIPLE LOOK-UP TABLES AND DATA ACQUISITION METHOD USING MULTIPLE LOOK-UP TABLES - A method for establishing multiple look-up tables and a data acquisition method using multiple look-up tables are provided. In the present method, a plurality of input data is classified into a plurality of groups, and a plurality of input data and a plurality of output data corresponding to the input data are respectively provided to the groups to establish a plurality of corresponding look-up tables. At least one bit is selectively removed from the input data in each of the look-up tables corresponding to at least one of the groups, and the result input data and the corresponding output data are recorded in the look-up table corresponding to the group. | 02-02-2012 |
20120082269 | METHOD FOR CHANNEL ESTIMATION AND DELAY SPREAD APPROXIMATION IN A WIRELESS COMMUNICATION SYSTEM - A method for delay spread approximation used in a wireless communication system comprises the steps of: retrieving a plurality of pilot symbols from a channel of a wireless communication system; calculating at least one parameter representing the shape of the frequency response of the channel according to the values and the relative positions of the pilot symbols; determining a representative parameter value according to the at least one parameter; and determining a delay spread value according to the representative parameter value. | 04-05-2012 |
20120147858 | METHOD FOR COMMUNICATION TRANSMISSION - A method for communication transmission includes the steps of: performing sub-frame transmission in accordance with a first communication standard and pausing sub-frame transmission in accordance with a second communication standard in a first communication period; performing a sub-frame uplink operation in accordance with the second communication standard and pausing a sub-frame uplink operation in accordance with the first communication standard in a second communication period; and performing a sub-frame downlink operation in accordance with the second communication standard and pausing a sub-frame downlink operation in accordance with the first communication standard in a third communication period. The transmission band of the first communication standard overlaps, at least partially, the transmission band of the second communication standard. | 06-14-2012 |