Abstract:
An OFDM DCM demodulation method is provided. The OFDM DCM demodulation method mainly includes the following steps. First, calculate a log likelihood of a first demodulation mode. Then calculate a log likelihood of a second demodulation mode. Finally, calculate a demodulation output according to the log likelihoods of the first demodulation mode and the second demodulation mode. The demodulation output may serve as an output of a demodulator of a receiving end of a DCM communication system.
Abstract:
A duplicate detection circuit for a receiver includes a CRC generator for generating a CRC value of frame header information, and a control circuit coupled to the CRC generator. The control circuit has a first output, a second output, and a control input. When the control input is not set, the control circuit outputs the CRC value at the first output. When the control input is set, the control circuit outputs the CRC value at the second output. A buffer has an input coupled to the first output of the control circuit. A compare circuit has an input coupled to an output of the buffer and another input coupled to the second output of the control circuit. The compare circuit compares a CRC value at the second output of the control circuit with a CRC value stored in the buffer, and outputs a duplicate indication when detecting a match.
Abstract:
A fast Walsh transform (FWT) demodulator and a method are provided. The FWT demodulator includes a FWT correlator for receiving and transforming a first information based on a FWT method to output third information; power approximation devices (PAD) for receiving and calculating one of the third information to output an approximating power value respectively. Wherein, the approximating power values are divided into subgroups. A first unit of comparators selects subgroup-max-values from each subgroup. A plurality of power calculation devices (PCD) are for receiving and calculating one of the subgroup-max-value to output a precise power value respectively. A second unit of comparators is for selecting max power value from each precise power value to output a second information. By applying “PAD” to replace “PCD” into “pre-selection” subgroups with “max-and-zero” property, the invention can reduce the implementation cost without performance degradation.
Abstract:
An I/O ESD protection circuit is provided utilizing a driver circuit, an ESD protection circuit, a Vcc/Vss protection circuit, and a clamping circuit. The driver circuit and the ESD protection circuit each comprise a NMOS cascode circuit. NMOS transistors and biasing resistive means comprise the Vcc/Vss protection circuit. The clamping circuit is a diode coupled between the I/O pad of the protection circuit and the gate of that NMOS transistor. In an ESD event the diode turns on the NMOS transistor of the Vcc/Vss protection circuit , thus clamping off the first transistor of both NMOS cascode circuits. The clamping inhibits the gate of those first two transistors to be coupled up by an ESD voltage and creates a parasitic bipolar transistor in each cascode circuit. The parasitic bipolar transistors provide a uniform current flow in the buried area of the P-well of both NMOS cascode circuits.
Abstract:
In a wireless communication method and system, a data/pilot constellation is modulated and generated based on input information bits. Channel estimation (CE) sequence in frequency-domain is off-line generated. The frequency-domain channel estimation sequence is transformed into a time-domain channel estimation sequence by ideal IFFT to avoid IFFT (Inverse Fast Fourier Transform) impact to EVM (Error Vector Magnitude) performance. Off-line resealing the time-domain CE sequence, multiplied by a rescaling coefficient, in time-domain improves EVM performance. Further, the time-domain channel estimation sequence is off-line quantized.
Abstract:
A fast Walsh transform (FWT) demodulator and a method are provided. The FWT demodulator includes a FWT correlator for receiving and transforming a first information based on a FWT method to output third information; power approximation devices (PAD) for receiving and calculating one of the third information to output an approximating power value respectively. Wherein, the approximating power values are divided into subgroups. A first unit of comparators selects subgroup-max-values from each subgroup. A plurality of power calculation devices (PCD) are for receiving and calculating one of the subgroup-max-value to output a precise power value respectively. A second unit of comparators is for selecting max power value from each precise power value to output a second information. By applying “PAD” to replace “PCD” into “pre-selection” subgroups with “max-and-zero” property, the invention can reduce the implementation cost without performance degradation.
Abstract:
A memory management method and a memory architecture for transmitting ultra-wideband (UWB) prioritized channel access (PCA) frames are provided. The method comprises the steps of assigning a pre-load queue to each of a plurality of access categories for storing UWB PCA frames to be transmitted, and, when one of the access categories gains transmission opportunity (TXOP), assigning a common area queue to that access category for storing UWB PCA frames to be transmitted. Moreover, when a UWB PCA frame in one of the pre-load queues reaches a predetermined size, the access category corresponding to the pre-load queue starts its backoff state machine in order to gain the TXOP.
Abstract:
A new ESD (Electrostatic Discharge) protection circuit with well-triggered PMOS is provided for application in power-rail ESD protection. A PMOS device is connected between the VDD and VSS power lines to sustain the ESD overstress current during the time that the ESD voltage is applied between the VDD and the VSS power lines. In deep submicron CMOS p-substrate technology, the weak point of ESD overstress control is typically associated with the NMOS device. For this reason, the invention uses a power-rail ESD clamp circuit that incorporates a PMOS device. Applying gate-coupled and N-well triggering techniques, the PMOS can be turned on more efficiently when the ESD overstress is present between the power lines. For p-substrate CMOS technology, it is difficult to couple a high voltage to the substrate of the NMOS device while high voltage is readily coupled to the N-well of a PMOS device. The proposed ESD clamp circuit can be applied efficiently to protect the ESD overstress between power rails.
Abstract:
An apparatus and a method for adaptive channel estimation and a coherent bandwidth estimation apparatus are provided. The adaptive channel estimation apparatus includes a first channel estimator, a coherent bandwidth estimator and a second channel estimator. The first channel estimator uses a predetermined approach to calculate a first channel response of each tone of an orthogonal frequency-division multiplexing (OFDM) signal. The coherent bandwidth estimator is coupled to the first channel estimator for calculating a coherent bandwidth according to the first channel responses. The second channel estimator is coupled to the first channel estimator and the coherent bandwidth estimator. For each of the tones, the second channel estimator calculates a weighted average according to the coherent bandwidth and the first channel responses of several adjacent tones including the aforementioned tone. The second channel estimator outputs the weighted average as the second channel response of the aforementioned tone.
Abstract:
A duplicate detection circuit for a receiver includes a CRC generator for generating a CRC value of frame header information, and a control circuit coupled to the CRC generator. The control circuit has a first output, a second output, and a control input. When the control input is not set, the control circuit outputs the CRC value at the first output. When the control input is set, the control circuit outputs the CRC value at the second output. A buffer has an input coupled to the first output of the control circuit. A compare circuit has an input coupled to an output of the buffer and another input coupled to the second output of the control circuit. The compare circuit compares a CRC value at the second output of the control circuit with a CRC value stored in the buffer, and outputs a duplicate indication when detecting a match.