## Abstract

In multiuser detection, maximum-likelihood detection (MLD) is optimum in the sense of minimum error probability. Unfortunately, MLD involves a computationally difficult optimization problem for which there is no known polynomial-time solution (with respect to the number of users). In this paper, we develop an approximate maximum-likelihood (ML) detector using semi-definite (SD) relaxation for the case of anti-podal data transmission. SD relaxation is an accurate and efficient approximation algorithm for certain difficult optimization problems. In MLD, SD relaxation is efficient in that its complexity is O(K^{3.5}), where K stands for the number of users. Simulation results indicate that the SD relaxation ML detector has its bit error performance close to the true ML detector, even when the cross-correlations between users are strong or the near-far effect is significant.

Original language | English (US) |
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Pages (from-to) | 6-10 |

Number of pages | 5 |

Journal | IEEE International Conference on Communications |

Volume | 1 |

State | Published - 2001 |

Event | International Conference on Communications (ICC2001) - Helsinki, Finland Duration: Jun 11 2000 → Jun 14 2000 |