V.I. Djigan1

1 Institute for Design Problems in Microelectronics of RAS (Zelenograd, Moscow, Russia)

Formulation of the problem. The computational complexity (the required number of arithmetic operations per sample of processed signals) of the adaptive antenna array (AAA) consists of two parts: the computational complexity of beamforming (the weighting and combination of the AAA input signals) and the computation of the weights of the AAA (the adaptive algorithm). The complexity of beamforming cannot be reduced because it depends on the number of AAA antennas/channels, which are selected to provide the required beamwidth of the AAA and its gain. However, the computational complexity of the adaptive algorithm can be reduced if the required number of adaptively controlled weights is much less than the total number of the AAA weights. The AAA that have such a relationship are called the partially adaptive arrays.

Target. In the case of the rectangular AAA, the partial adaptation can be achieved by the combination in the base-band signals received by the antennas in the rows and columns of the rectangular array before their adaptive weighting. This makes it possible to reduce the computational complexity of the adaptive algorithm if the total number of received signals (information one and interferences) is less than the total number of the AAP rows and columns. This reduces the number of adaptively computed/controlled weights while provides nearly the same steady state performance as that of the fully adaptive AAA. If the AAA is symmetric (its weights have an odd symmetry with the respect to the location of the corresponding antennas over the aperture), then the further reduction in the computational complexity of the AAA can be achieved by the using of the adaptive algorithm with the most of the computations in the real-valued arithmetic.

Results. This paper presents the results of the development and the investigation of the partially adaptive rectangular antenna array with the combination of the row and column signals and the combined signal processing in the real-valued arithmetic. The AAA architecture, the procedure for computations of its weights, and the AAA simulation results are presented. The simulation shows that the considered symmetric AAA in the real-valued arithmetic provides approximately a twice shorter transient response and an approximately 3 dB better steady state interference cancellation comparing to the AAA in the asymmetric complex-valued arithmetic.

Practical significance. The proposed algorithm can be used in the receiving rectangular adaptive antenna array with the digital beamforming and with the limited computational resources for this array implementation.

Djigan V.I. Antenna array with partial adaptation based on Recursive Least Squares algorithm in real-valued arithmetic. Radiotekhnika. 2023. V. 87. № 1. P. 144−157. DOI: https://doi.org/10.18127/j00338486-202301-11 (In Russian)

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