Degree-of-Freedom Strengthened Cascade Array for DOD-DOA Estimation in MIMO Array Systems.

Area of Science:

• Signal Processing
• Array Signal Processing
• Electromagnetics

Background:

• Spatial spectrum estimation relies on difference co-arrays to enhance degrees-of-freedom (DOFs).
• Existing array structures have limitations in maximizing DOFs for improved parameter identifiability and estimation accuracy.

Purpose of the Study:

• To design a novel sensor array geometry, the cascade array, to maximize DOFs from a limited number of physical sensors.
• To develop a joint direction of departure (DOD) and direction of arrival (DOA) estimation algorithm for multiple-input multiple-output (MIMO) systems utilizing the cascade array.

Main Methods:

• The cascade array is constructed by combining a uniform linear array (ULA) and a non-uniform linear array.
• A reduced-dimensional weighted subspace fitting technique is employed for the joint DOD/DOA estimation algorithm.
• Theoretical analysis and numerical simulations are used to validate the proposed methods.

Main Results:

• The proposed cascade array provides more DOFs than existing structures, though fewer than the theoretical maximum from a minimum redundant array (MRA).
• The joint DOD/DOA estimation algorithm is angle auto-paired and computationally efficient.
• The effectiveness of the cascade array and the estimation algorithm is demonstrated through simulations.

Conclusions:

• The novel cascade array design effectively increases DOFs for spatial spectrum estimation.
• The proposed joint DOD/DOA estimation algorithm for MIMO systems using the cascade array is advantageous and efficient.