Abstract: A method of enhancing accuracy of position estimation for a wireless communication system includes receiving a plurality of input measurements required for estimating a position of a target, and generating a plurality of Gaussian probability density functions corresponding to the plurality of input measurements, the plurality of Gaussian probability density functions being used for estimating the position of the target.

Abstract: A method for determining a position of a mobile station in a wireless communication system includes generating a state equation set according to a current state of the mobile station, for predicting a position and a velocity of the mobile station after a predetermined period, and corresponding the state equation set to a graphic interface for calculating the position and the velocity after the predetermined period.

Abstract: A method for detecting radar signal comprises the steps of: receiving a signal by a receiver, wherein the strength of the received signal is controlled within a range; sampling the received signal so as to obtain a plurality of sampling values; dividing the sampling values into a plurality of segments; summing up the absolute values of the sampling values in each segment; and determining that the received signal includes radar signals if at least one summation is greater than a threshold.

Abstract: The present invention provides a method for simplifying a probabilistic rate adaptation procedure in a wireless communication system, which comprises calculating a conditional probability density function of SNR of a transmitted signal by the probabilistic rate adaptation procedure, to generate an SNR estimation result, taking logarithm on the SNR estimation result to generate a logarithm result, and partitioning SNR values into a plurality of regions according to the logarithm result, to generate a discrete function from the SNR estimation result.

Abstract: A method and related system of transmission channel detection condition in a wireless communication system are disclosed. The method includes receiving a symbol, performing a channel estimation operation to generate a channel estimation result according to the symbol, performing a cross correlation operation on the channel estimation result and an initial channel estimation result to generate an operation result, and determining whether the condition of the transmission channel have changed or not.

Abstract: A method for determining a modulation and coding scheme for signals with packets of different lengths comprises the steps of: grouping signals according to their packet lengths, wherein each group has a weighting for each modulation and coding scheme; transmitting signals with different modulation and coding schemes; adjusting weights of each modulation and coding scheme of each group according to the quality of receiving the transmitted signals; determining a modulation and coding scheme according to the weightings of each modulation and coding scheme in the group corresponding to the packet length of the signal to be transmitted.

Abstract: A lookup table generation method for a predistorter comprises sending a first single tone signal with a maximum expected amplitude to a channel simulation device including the power amplifier, estimating a closed loop gain and a closed loop phase of the power amplifier according to the first single tone signal and a first simulation output signal generated outputted by the channel simulation device, sending a plurality of single tone signals to the channel simulation device, each single tone signal having an amplitude different from all others of the plurality of single tone signals and lower than the maximum expected amplitude, generating a plurality of predistortion parameters according to the closed loop gain, the closed loop phase, the plurality of single tone signals and a plurality of simulation output signals outputted by the channel simulation device, and storing the plurality of predistortion parameters in a lookup table of the predistorter.

Abstract: A method of examining the eligibility of a modulation and coding scheme includes determining a range of pseudo signal-to-noise ratio (pseudo-SNR) corresponding to a range of packet correct rate (PCR) acceptable for a transmitter, obtaining a first score of a positive acknowledgement (ACK) and a second score of a negative acknowledgement (NACK) according to the range of pseudo-SNR and the range of PCR, applying weighting to a score of a response message, which is one of an ACK message and a NACK message, and a pseudo-SNR corresponding to an immediately preceding response message when receiving the response message, for generating a pseudo-SNR corresponding to the response message, and examining the eligibility of a modulation and coding scheme in use according to the pseudo-SNR corresponding to the response message.

Abstract: The present invention provides a method for enhancing accuracy of rate adaptation in a transmitter of a wireless communication system, which comprises setting a plurality of scores indicating reliabilities of a plurality of MCSs of the wireless communication system during rate adaption procedures of the plurality of MCSs, and adjusting the plurality of scores according to a plurality of response messages indicating receiving statuses of a plurality of transmitted packets.

Abstract: A method for determining a modulation and coding scheme comprises the steps of: transmitting signals with different modulation and coding schemes and adjusting weighting of each modulation and coding scheme based on the quality of transmitted signals on a receiving end; adjusting the weighting of each modulation and coding scheme based on suggested modulation and coding schemes; determining a modulation and coding scheme to use according to the weighting of each modulation and coding scheme.

Abstract: A method for adjusting a modulation and coding scheme based on signal quality comprises the steps of: determining a reference modulation and coding scheme based on signal reception qualities of transmitted signals according to a plurality of modulation and coding schemes; determining a temporary modulation and coding scheme according to a modulation and coding scheme selection method; determining a final modulation and coding scheme according to a first table and the differences between the reference modulation and coding scheme and the temporary modulation and coding scheme.

Abstract: A method for selecting modulation and coding scheme (MCS) for multi-antenna systems comprises the steps of: a multi-antenna system transmits signals according to MCSs of single spatial stream and determines an MCS accordingly. Subsequently, the multi-antenna system increases the number of the spatial streams applied, transmits signals according to the corresponding MCSs and determines an MCS accordingly until an optimum MCS is found.

Abstract: The module for switching between a long guard interval and a short guard interval comprises a signal processing unit, a measurement unit, a comparison unit and a switching unit. The module receives a first data symbol, and the data symbol has one of a long guard interval and a short guard interval. The signal processing unit is configured to generate a second data symbol in accordance with the first data symbol. The measurement unit is configured to measure a portion of the first and second data symbols in order to generate a first measurement value and a second measurement value. The comparison unit is configured to generate an output signal by comparing the first and second measurement values with a threshold value. The switching unit is configured to selectively switch guard intervals of subsequent data symbols in accordance with the output signal.

Abstract: An approximation method for SNR soft information for a transmitter of a communications system includes obtaining a conditional probability density function (PDF) corresponding to a response message of a transmitted packet, obtaining a PDF of a probability distribution model, and a mean and a variance of the PDF, by approximating the conditional PDF corresponding to the response message with the probability distribution model, and calculating a second mean and a second variance of a second PDF approximated to a conditional PDF of SNR corresponding to the transmitted packet according to the mean and the variance of the PDF, and a first mean and a first variance of a first PDF approximated to a conditional PDF of SNR corresponding to another transmitted packet immediately preceding the transmitted packet.

Abstract: The method for beamforming in a wireless communication system comprises the steps of: receiving a sounding packet so as to estimate channel state information between a transmitter and a receiver; generating a beamforming matrix in accordance with the channel state information; generating a beamforming steering matrix by multiplying the beamforming matrix by a rotation matrix; and feeding back the beamforming steering matrix.

Abstract: A method for decoding LDPC code comprises the steps of: marking non-zero sub-matrices of a parity-check matrix of an LDPC code as 1 and zero sub-matrices of the parity-check matrix as 0 to form a simplified matrix; rearranging the sequence of rows of the simplified matrix according to the dependency between these rows; and updating the LDPC code in accordance with the sequence of the rows.

Abstract: A method for decomposing a barrel shifter decomposes N, the number of digits of input word, into N1 to Nm, and utilizes m layers of shifter circuit layer, which are composed of a plurality of barrel shifters, such that each barrel shifter performs a shifting procedure to obtain the desired output word.

Abstract: A method for calibrating an analog circuit component comprises the steps of: generating a first signal with a baseband frequency; generating a second signal by processing the first signal via the analog component to be calibrated; generating a third signal by processing the second signal via a power amplifier, wherein the power amplifier operates in a nonlinear region; generating a fourth signal by processing the third signal via a low-pass filter; and defining the adjustment for the In-phase-Quadrature-phase imbalance (IQ imbalance) of the analog component and then re-executing the step of generating the first signal, if the fourth signal shows an IQ imbalance mismatch.

Abstract: A method and a system for reading radio frequency identification (RFID) tags are provided. The method includes the following steps. First, receive a tag signal from the RFID tag. Recover a data clock rate from the tag signal according to statistics of pulse lengths of the tag signal. Next, determine a frame synchronization point of a data frame following a preamble in the tag signal by a signal correlation between the preamble and a predetermined signal pattern according to the data clock rate. Finally, decode the data frame by using an adaptive Viterbi algorithm on an extended trellis diagram. The extended trellis diagram includes a plurality of nodes and a plurality of branches connecting the nodes. The nodes and the branches are arranged according to the modulation scheme of the data frame and possible variations of the data clock rate.

Abstract: A method for selecting a modulation and coding scheme (MCS) applied to a multiple-antenna system. The method calculates the throughout of a plurality of MCSs based on the signal to noise ratio of the multiple-antenna system and selects a MCS from the plurality of MCSs accordingly.