Design of High Doppler Tolerance Orthogonal Sequence Set via Ambiguity Functions Shaping

The orthogonal sequence set with high Doppler tolerance is widely utilized in the context of moving target detection in multiple-input multiple-output (MIMO) system. This article addresses the issue of designing unimodular orthogonal sequence sets via shaping auto-ambiguity function (AAF) and cross-ambiguity function (CAF). Specifically, the optimization process involves minimizing the normalized energy of sidelobes in AAFs and CAFs, while enforcing a constant modulus constraint on the sequence set. To tackle the non-convex, quartic model, an optimization algorithm based on the consensus-altering direction method of the multipliers framework is employed. This algorithm enables the processing of each sub-problem independently within a distributed processing framework. Finally, the results of numerical experiments conducted under various parameters demonstrate the effectiveness and advancement of the proposed method in terms of correlation performance.