IEEE 802.15.4 receiver with demodulation phase dependent upon early/on time/late correlations of oversampled pseudo noise spread signal

摘要

IEEE 802.15.4/Zigbee receiver for Low Rate Wireless Personal Area Networks (LR-WPAN) with low power consumption to conserve battery life. Incoming signal is amplified, analogue to digital converted (ADC) and oversampled 70. Samples are correlated with known pseudonoise (PN) chip patterns at early/punctual/late timings 72 (see also Fig. 4) and correlation peaks are fed to timing control unit 82/84. This compares the three correlation levels to determine if the phase of the chip rate clock 86 is synchronised with the incoming signal and adjusts it as necessary. Averaging 74 of correlator outputs before symbol decisions 76 can improve signal to noise ration of the receiver. Signal quality analysis based on average received signal strength (ARSSI) and noise 80 may be used to control amplification, ADC resolution and/or ADC oversampling rate.