The effects of single bit quantization on direction of arrival estimation of UHF RFID tags

Phased arrays can be used to estimate the direction-of-arrival (DOA) of UHF RFID tags. To save on energy consumption and hardware costs, in this paper we explore the possibility of using single bit analog-to-digital converters for our phased array setup. This setup consists of an off-the-shelf Impinj R2000 reader and a custom phased array with 4 receiving channels. The proposed system quantizes the baseband quadrature signals individually. As there is a direct relation between the correlation coefficient of a quantized signal and an unquantized signal, the error introduced by quantization can be corrected. The experimental results show that single bit quantization can be used for DOA estimation and the mean error increases only slightly. The proposed correction achieves better results than uncorrected quantized estimation, at the cost of the need for signal power measurements.