EURASIP Journal on Applied Signal Processing
Distributed Phased Arrays and Wireless Beamforming Networks
International Journal of Distributed Sensor Networks
Performance of vector perturbation multiuser MIMO systems with limited feedback
IEEE Transactions on Communications
Robust approaches to remote calibration of a transmitting array
Signal Processing
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This work describes two algorithms designed for remote calibration of an Nc-element active phased-array antenna. These algorithms involve transmission of N⩾Nc time multiplexed orthogonal encoded signals. The received signals are coherently detected, accumulated in vector forms, and decoded with the inverse of the orthogonal encoding matrix. The unitary transform encoding (UTE) algorithm is most suited for digital beamforming as it requires additional encoding hardware for an analog implementation. The control circuit encoding (CCE) algorithm is ideally suited for analog beamformers as it requires no additional encoding hardware. The CCE method encodes phased-array elemental signals using a Hadamard matrix to control the switching of intrinsic phase shifter delay circuits. The UTE and CCE algorithms can reduce the average measurement integration times for the complete set of calibration parameters by ~Nc relative to the corresponding values for single-element calibration procedures. This is significant for satellite systems as calibration must be performed in a short enough time window that the process can be treated as being stationary. Proofs are given that the orthogonal codes satisfy the mathematical lower bounds for the asymptotic forms of calibration parameter estimation variances