BER analysis of BPSK and QPSK constellations in the presence of ADC quantization noise

Quantization noise (QN) due to limited analog to digital converter (ADC) word length gives rise to degradation in system performance, especially in high frequency communication systems with sampling rates in the range of giga samples per second (Gsps). In this paper, expressions are derived for the evaluation of the bit error rate (BER) of binary phase shift keying (BPSK) and quadrature PSK (QPSK) signal constellations as a function of ADC word length (NADC) and signal to noise ratio (SNR) due to additive white Gaussian noise (AWGN). It is shown that unlike the AWGN case, system performance is dependent on the signal constellation rotation when QN due to the ADC is dominant. The newly derived expressions are then used to investigate the impact of constellation rotation on the system BER performance. It is shown that considerable performance gains can be achieved with an appropriate rotation of the signal constellation.