An Efficient Broadband Adaptive Beamformer without Presteering Delays.

Area of Science:

• Signal Processing
• Array Signal Processing
• Adaptive Filtering

Background:

• Broadband adaptive beamformers filter signals in both space and frequency domains.
• Traditional methods require direction-dependent presteering delays, which are difficult to implement precisely.
• Existing constraint methods on weight vectors have high computational complexity (O(N^2)) due to neglecting constraint matrix structure.

Purpose of the Study:

• To develop a new time-domain constraint method for broadband adaptive beamformers.
• To reduce the computational complexity of weight vector updates.
• To design an algorithm suitable for hardware implementation (e.g., FPGA) with high constraint accuracy.

Main Methods:

• Introduced a time-domain constraint method that preserves the block diagonal structure of the constraint matrix.
• Developed an efficient weight vector update algorithm with O(N) computational complexity.
• Ensured the algorithm involves only scalar and vector operations, avoiding matrix operations.

Main Results:

• The proposed algorithm achieves a computational complexity of O(N), a significant reduction from O(N^2).
• The method is easily implementable on hardware like FPGAs due to the absence of matrix operations.
• Constraint accuracy is comparable to frequency constraint methods for signals with fractional bandwidth < 10%.

Conclusions:

• The novel time-domain constraint method offers a simpler and computationally cheaper alternative for broadband adaptive beamformers.
• The algorithm achieves state-of-the-art performance with reduced complexity and improved hardware compatibility.
• This method is particularly advantageous for applications requiring efficient and accurate signal filtering.