(A) high sensitivity, interference resistant BFSK multi-channel ULP receiver using frequency to amplitude conversion for IoT applications

Abstract

With the rapid growth of the internet of things (IoT) market, our lives are becoming more convenient through monitoring, sensing, sharing and utilizing the information in applications such as healthcare, smart factories, home automation, and autonomous navigation. Considering the IoT concept that different devices are interconnected at various locations for various application groups, the performance of a wireless receiver is one of the most significant features of the efficient IoT network. The main three key performance of receiver are the following: low-power operation, high sensitivity, and multi-channel operation with robustness to interference. Although ultra-low power (ULP) receivers have been proposed previously, most ULP receivers either show relatively low sensitivity and single-channel operation at the cost of low-power implementation, or consume high power in exchange for high sensitivity and multi-channel operation. This dissertation proposes a 2.4 GHz, high sensitivity and interference-resistant, multi-channel ultra-low power receiver for long-distance IoT applications. A hybrid complex poly-phase filter is used to convert an input frequency-shift keying (FSK) signal into an on-off keying (OOK) signal with amplitude information to combine the advantages of OOK and FSK modulations. The sliding-IF architecture is adopted to achieve the multi-channel operation with low-power consumption. For ultra-low power implementation, the low-power mixers are devised for the low-power down-conversion. Furthermore, narrow band filtering and strong immunity against interfere are achieved by two series-connected N-path filters and a fourth-order hybrid complex poly-phase filter respectively. Implemented in a 65 nm CMOS, the receiver achieves a -102 dBm of sensitivity at 0.1% bit error rate and less than -50 dB of carrier-to-interferer ratio at 5 MHz offset while consuming 466 μW from a 0.6 V supply.