## Abstract

The sum-capacity of the multi-antenna Gaussian broadcast channel is known to be achieved by Dirty Paper Coding techniques, that require full channel state information at the base station. It has been recently shown that a sum-rate having the same scaling law of the sum-capacity with respect to the number of users n for a fixed signal to noise ratio (i.e., M log log n where M is the number of transmitting antennas) can be achieved by using reduced feedback (or equivalently reduced channel state information at the transmitter). In particular, it has been proved that n real and n integer numbers are enough to guarantee the optimal scaling law. In this paper, the optimal scaling law of the sum-rate is shown to be achievable with an even smaller amount of feedback and, more precisely, with 1) n log_{2} (M + 1) bits, if a deterministic feedback scheme is employed; 2) an average number of feedback bits that scales as M log_{2} M log n with the number of users n, if a selective (random) feedback scheme is employed.

Original language | English (US) |
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Title of host publication | 2006 IEEE Information Theory Workshop, ITW 2006 |

Pages | 298-301 |

Number of pages | 4 |

State | Published - Nov 21 2006 |

Event | 2006 IEEE Information Theory Workshop, ITW 2006 - Punta del Este, Uruguay Duration: Mar 13 2006 → Mar 17 2006 |

### Other

Other | 2006 IEEE Information Theory Workshop, ITW 2006 |
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Country/Territory | Uruguay |

City | Punta del Este |

Period | 3/13/06 → 3/17/06 |

## All Science Journal Classification (ASJC) codes

- Engineering(all)