摘要:
Methods and apparatus are provided for spread spectrum signal processing in a wireless communication system. The apparatus includes a control processor to generate commands for processing spread spectrum signal components and a reconfigurable coprocessor to process the spread spectrum signal components based on the commands and to provide reports to the control processor based on results of processing the signal components.
摘要:
A homodyne receiver is provided for receiving GSM and UMTS transmissions. The receiver may also be used for other transmission schemes. The receiver includes an electronically reconfigurable low pass filter and an off set generator for providing DC offset correction for offsets which may be generated as a result of coupling between a local radio frequency oscillator and the receiver front end.
摘要:
A wireless charging in-band communication system includes a transmitter module that formats a message using CRC calculation and attaches the results of the CRC calculation to the message for message error detection. The transmitter includes channel encoding for message error correction. A modulation module performs biphase modulation for DC balanced signals and impedance switching to change reflected impedance seen by the source. A synchronization module prepending the message with a synchronization sequence having Golay complementary codes. Moreover, the in-band communication includes a receiver module that receives the message from the transmitter module. The receiver module includes an impedance sensing circuit to detect changes in the reflected impedance of the transmitter module. The receiver module includes a front end filter used for pulse shaping and noise rejection. A preamble detection block includes a Golay complementary code correlator used for message detection, synchronization, and equalization coefficient estimation and selection. A decoding module performs biphase demodulation with error correction with a DC offset being estimated as the average value of the signal over the length of the message before channel decoding Also, the decoding module performs equalization, error correction channel decoding,and error detection (CRC).
摘要:
A reduced complexity turbo decoding scheme combines elements from two MAP (Maximum a posteriori) algorithms, namely a LogMAP algorithm and a max-LogMAP algorithm. Forward and backward recursive metrics are computed in accordance with the max-LogMAP algorithm, while output extrinsic LLR (Log Likelihood Ratio) values are computed in accordance with the LogMAP algorithm.
摘要:
A system and method are provided for determining whether a chipping code from a group of codes is used in a signal. In one embodiment of the invention, a signal is received and each code from the group is correlated with the received signal. The ratio of the highest correlation value to the second highest correlation value is calculated. If the ratio exceeds a threshold, the chipping code may be determined as the chipping code used in the signal. In another embodiment, the ratio of the highest correlation value and the total received power of the signal is calculated. If the ratio exceeds a threshold, the chipping code may be determined as the chipping code used in the signal.
摘要:
Although DC offset reduction schemes can be applied in the analog domain, the residual static DCO in baseband is still present, significantly influencing the performance of high-level modulation schemes employed by recent high-data-rate wireless communications standards. In order to achieve satisfactory performance, DCO compensation algorithms are required in the digital domain. One such algorithm was developed which is based on joint estimation of the Channel Impulse Response (CIR) and the static DCO and ensures satisfactory performance of EDGE modem with direct conversion radio architectures. A further modification of the joint estimation algorithm, the so-called “perturbed joint L”, results in further improvement in the performance of the EDGE equalizer in critical fading channels.
摘要:
A receiver unit includes a prefilter that receives as one of the inputs a channel impulse response (CIR) estimation data set and removes unnecessary data information from the CIR estimation data set and filters input signal so to form a first output data set. An equalizer core receives the first output data set and based on computed CIR length and SNR value of the first output data set so as to determine which portion of the first output data set are assigned to at least one of at least two low complexity equalization modules used for processing.
摘要:
Although DC offset reduction schemes can be applied in the analog domain, the residual static DCO in baseband is still present, significantly influencing the performance of high-level modulation schemes employed by recent high-data-rate wireless communications standards. In order to achieve satisfactory performance, DCO compensation algorithms are required in the digital domain. One such algorithm was developed which is based on joint estimation of the Channel Impulse Response (CIR) and the static DCO and ensures satisfactory performance of EDGE modem with direct conversion radio architectures. A further modification of the joint estimation algorithm, the so-called “perturbed joint L”, results in further improvement in the performance of the EDGE equalizer in critical fading channels.
摘要:
A method for reducing DC offset from a receiver signal. The method includes jointly (i.e., simultaneously) estimating such DC offset and channel impulse response, and reducing the DC offset in accordance with the estimated DC offset and the estimate of the channel impulse response.
摘要:
A wireless communication system is provided that includes a base station receiving a plurality of input signals that are selectively provided to a plurality of precoders. The precoders perform precoding operations on the input signals and output a first signal. The base station includes an algorithm that minimizes total transmit power per antenna under signal to interference and noise ratio (SINR) target constraints or maximizes the SINR under a sum of power constraint so as to determine power allocation and obtain efficient precoders. A number of mobile receiver units receive the first signal and performs their respective operations to extrapolate the linear estimate of the input signals.