Manoj Choudhary

Timing synchronization in super-regenerative receivers with a single quench cycle per symbol

Super-regenerative receivers (SRR) are known for their ultra-low power (ULP) consumption. However, its wide frequency selectivity seriously degrades performance especially in the presence of interference. An attractive approach to address this problem is by lowering the quench rate of the SRR to the modulation rate. However, this brings in uncertainty due to lack of oversamples and leads to the timing synchronization problem in demodulation. This paper proposes a timing synchronization method for SRR with a single quench cycle per modulated symbol. A novel asynchronous preamble structure and an associated timing synchronization algorithm are proposed. Significant performance gains are obtained due to the improved frequency selectivity enabling the SRR system to adhere to the constraints set forth by the IEEE 802.15.4 standard while maintaining the ULP advantage.

Performance analysis of non-coherent OOK detection with complex BPF based low IF receiver

We consider a non-coherent receiver architecture with low IF frequency down-conversion, complex band pass filtering and envelope detection for ultra low power (ULP) wireless communications. We model and evaluate the performance of ULP transceiver with IEEE 802.15.4q PHY packet format. Moreover, we provide a theoretical analysis of the image rejection properties of low IF receiver. We evaluate the performance of the low IF receiver via PER sweeps and ACI tests. Finally, we compare its performance with that of Weaver receiver.

DC offset estimation for on-off keying based ultra-low power non-coherent receivers

Two methods to estimate the direct current offset (DCO) of non-coherent receivers for on-off keying (OOK) systems are proposed. These estimate I-arm and Q-arm DCO solely from the digitized samples of the envelope detector. This ameliorates power consuming individual I-arm and Q-arm processing for DCO estimation and makes it more suitable for adoption in next generation wireless ultra-low power (ULP) receivers. Furthermore, the efficacy of the proposed methods is demonstrated for an IEEE 802.15.4q compliant ULP sliding intermediate frequency receiver.