Mixed-Precision Arrangement via CRB for DOA Estimation Using SLA

We consider a mixed analog-to-digital converter (ADC) based architecture for the direction of arrival (DOA) estimation under sparse linear arrays (SLAs) with arbitrary structure. Given the fixed number of ADCs, the arrangement of high-precision and one-bit ADCs in SLA is analyzed using Cramér-Rao bound (CRB). To obtain the optimal mixed-precision arrangement, we simplify the problem into a 0–1 integer quadratic programming and efficiently solve it by using the alternating direction method of multipliers (ADMM) algorithm. Simulation results validate the effectiveness of our approach. Furthermore, SLAs, such as the nested and co-prime array, can achieve a lower CRB with the optimal mixed-precision arrangement.