## Abstract

Convex relaxations of the optimal finger selection algorithm are proposed for a minimum mean square error (MMSE) Rake receiver in an impulse radio ultra-wideband system. First, the optimal finger selection problem is formulated as an integer programming problem with a non-convex objective function. Then, the objective function is approximated by a convex function and the integer programming problem is solved by means of constraint relaxation techniques. The proposed algorithms are suboptimal due to the approximate objective function and the constraint relaxation steps. However, they can be used in conjunction with the conventional finger selection algorithm, which is suboptimal on its own since it ignores the correlation between multipath components, to obtain performances reasonably close to that of the optimal scheme that cannot be implemented in practice due to its complexity. The proposed algorithms leverage convexity of the optimization problem formulations, which is the watershed between 'easy' and 'difficult' optimization problems.

Original language | English (US) |
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Article number | PHY38-4 |

Pages (from-to) | 861-866 |

Number of pages | 6 |

Journal | IEEE Wireless Communications and Networking Conference, WCNC |

Volume | 2 |

State | Published - 2005 |

Event | 2005 IEEE Wireless Communications and Networking Conference, WCNC 2005: Broadband Wirelss for the Masses - Ready for Take-off - New Orleans, LA, United States Duration: Mar 13 2005 → Mar 17 2005 |

## All Science Journal Classification (ASJC) codes

- General Engineering

## Keywords

- Convex optimization
- Impulse radio (IR)
- Integer programming
- MMSE Rake receiver
- Ultra-wideband (UWB)