Using Multiple Chains in Cross-Correlation Receivers to Improve Sensitivity

Abstract

Cross-correlation can be used in energy detection applications, such as spectrum analyzers, but also frequency shift keying (FSK) receivers, to improve noise suppression. To achieve higher signal-to-noise ratio (SNR), integration in time may be used, but could make it rather slow for communication purposes. In order to achieve better data-rates in low SNR conditions, we propose to use multiple chains instead of the traditional two chains. In this paper, we show an analysis of the SNR improvement and the power consumption penalty for BFSK modulation when using more chains. It shows that for low noise correlation between the chains, the improvement in sensitivity is proportional to the number of chains. Also, we develop a figureof-merit to evaluate the optimum number of chains for different parameters of the receiver design. Furthermore, two examples from literature are analyzed. At their optimum number of chains, they both show ∼6dB improvement in sensitivity with similar or even better figure-of-merit.

Multi-Receiver Cross-Correlation Technique for (B)FSK Radios

“…Such signal detection in FSK discriminators can be improved through XC technique. We demonstrated this in [7], [8] through theoretical calculations and MATLAB simulations.…”

“…Alternatively in [8], we increased the number of crosspower spectrum samples by increasing the number of receivers used in the XC, as shown in Fig. 3.…”

“…Recently, we proposed to use XC for data-communication in receivers targeting wireless sensor networks [7], [8]. Among digital modulation schemes, Frequency Shift Keying (FSK) is chosen as it can be demodulated using the energy detection principle in the frequency discriminator [8], [9]. As seen in Fig.…”

“…time [4], [8]. The effect of multi-receiver XC on the bit error rate of BFSK receivers is mathematically analysed in [8], but without experimental verification.…”

“…time [4], [8]. The effect of multi-receiver XC on the bit error rate of BFSK receivers is mathematically analysed in [8], but without experimental verification. In this work, we implemented the multi-receiver XC technique in a BFSK receiver using state-of-the-art sub-mW front-end, designed for IoT applications [13] and evaluated experimentally the improvement in sensitivity and harmonic interferer tolerance of the receiver.…”