Early Companion-Vector CORDIC Architecture for QRD-RLS Systolic Adaptive Beamforming: Evidence from Publications by Roger Guorong Hu, 1990–1994

Abstract

This historical technical report reconstructs and documents early CORDIC-based QR-decomposition recursive least-squares (QRD-RLS) systolic architectures for adaptive beamforming developed and published by Roger Guorong Hu and collaborators between 1990 and 1994. The central documentary evidence is the DOI-indexed 1991 IEEE conference paper, “An ASIC Design for Adaptive Beamforming” (DOI: 10.1109/CICCAS.1991.184490). That paper explicitly states that the trigonometric result associated with a Givens rotation can be obtained by rotating the auxiliary unit vector (0,1) through the same CORDIC operation. It also presents the associated product-of-cosines relationship, CORDIC pseudo-multiplication recurrences, systolic processing cells, microprogrammed control, ASIC layout, and implementation results. The paper attributes a more detailed description of the architecture to Hu and Sun’s 1990 ICSP publication, “CORDIC Implementation of the RLS Systolic Array.” This auxiliary unit-vector co-rotation technique—also described in modern terminology as companion-vector or dummy-vector co-rotation—reuses the CORDIC rotation decisions and shift-add structures already present in the systolic array. It obtains the required trigonometric information and supports scale-factor processing without a separate trigonometric lookup table or conventional general-purpose multiplier datapath. The published 1991 paper uses the vector (0,1); under an exchanged coordinate convention, the same architectural principle may be represented using the commonly illustrated dummy vector (1,0). The surviving publication record establishes that this companion-unit-vector CORDIC architecture was published by Hu and collaborators no later than 1991, while the 1991 IEEE paper points to their 1990 ICSP paper for the detailed implementation. This report distinguishes directly verified documentary evidence from technical reconstruction and does not claim that a comprehensive worldwide pre-1990 prior-art search has been completed. Author identity note: Roger Guorong Hu is the same researcher identified as Guorong Hu, Hu Guorong, G. Hu, and 胡国荣 in historical publications and bibliographic records. Related publications: Hu, G., Sun, Y., and Hou, C., “An ASIC Design for Adaptive Beamforming,” China 1991 International Conference on Circuits and Systems, pp. 832–834. DOI: https://doi.org/10.1109/CICCAS.1991.184490 Hu, G., Han, Y., and Chin, L., “ASSP-Based Radar Signal Processing,” Journal of Electronics (China), vol. 17, pp. 146–152, 2000. DOI: https://doi.org/10.1007/BF02903192