Optimal Binary/Quaternary Adaptive Signature Design for Code-Division Multiplexing
The authors consider signature waveform design for synchronous code division multiplexing in the presence of interference and wireless multipath fading channels. The adaptive real/complex signature that maximizes the Signal-to-Interference plus-Noise Ratio (SINR) at the output of the maximum-SINR filter is the minimum-eigen-value eigenvector of the disturbance auto-covariance matrix. In digital communication systems, the signature alphabet is finite and digital signature optimization is NP-hard. In this paper, first they convert the maximum-SINR objective of adaptive binary signature design into an equivalent minimization problem. Then, they present an adaptive binary signature design algorithm based on modified Fincke-Pohst (FP) method that achieves the optimal exhaustive search performance with low complexity.