A Simplified Sub-Nyquist Receiver Architecture for Joint DOA and   Frequency Estimation
  Joint estimation of carrier frequency and direction of arrival (DOA) for multiple signals has been found in many practical applications such as Cognitive Radio (CR). However, Nyquist sampling mechanism is costly or implemented due to wide spectrum range. Taking advantage of sub-Nyquist sampling technology, some array receiver architectures are proposed to realize joint estimation of carrier frequency and DOA. To further decrease equivalent sampling rate and hardware complexity, we propose a simplifying receiver architecture based on our previous work. We come up with joint DOA and frequency estimation algorithms for the novel architecture. The simulations demonstrate that the receiver architecture and the proposed approaches are feasible. 
Liang Liu and Ping Wei
cs.IT math.IT