Greedy Code Search Based Memetic Algorithm for the Design of Orthogonal Polyphase Code Sets

Multiple-input-multiple-output (MIMO) radar has received significant attention because it offers broad design freedom and superior performance. Polyphase code sets with low autocorrelation sidelobe peaks and low cross-correlation peaks, also known as orthogonal polyphase code sets, can be used as transmission signals by MIMO radar. We present an effective algorithm named the greedy code search-based memetic algorithm (MA-GCS) to design such code sets. MA-GCS is a novel variation of the new evolutionary search, which can be used to design only a single binary sequence with low autocorrelation peaks. MA-GCS integrates an evolutionary search for global searches and a GCS for local searches to improve the accuracy of solutions. Moreover, an accelerating algorithm is designed to reduce the computational complexity of the GCS-based local search. The computational complexity of our algorithm is derived and compared with other algorithms. It is demonstrated by the experimental results that our algorithm is truly effective. On one hand, the code sets designed using our proposed algorithm have better autocorrelation and cross-correlation properties than other methods. On the other hand, the time consumed is acceptable. In addition, the influence of the code set parameters on the performance of the design results is also investigated.