### Abstract

We consider a fully connected network with S full duplex source nodes, D full duplex destination nodes and R relay nodes, perfect feedback to source and relay nodes, and noisy cooperation between all source, relay and destination nodes. We show that this network has SD/S+D-1 degrees of freedom if the channel gains are time-varying/frequency selective. The implication of the result is that, the techniques mentioned in the title (i.e relays etc.) can affect the capacity of a network only upto a o(log(SNR,)) term and therefore cannot improve the degrees of freedom of a network. Certain communication scenarios excluded by our system model where these techniques improve the degrees of freedom are also identified. Bounds on the degrees of freedom of a fully connected K node network emerge as a by-product of our study.

Original language | English (US) |
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Title of host publication | Proceedings - 2008 IEEE International Symposium on Information Theory, ISIT 2008 |

Pages | 1263-1267 |

Number of pages | 5 |

DOIs | |

State | Published - Sep 29 2008 |

Event | 2008 IEEE International Symposium on Information Theory, ISIT 2008 - Toronto, ON, Canada Duration: Jul 6 2008 → Jul 11 2008 |

### Publication series

Name | IEEE International Symposium on Information Theory - Proceedings |
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ISSN (Print) | 2157-8101 |

### Other

Other | 2008 IEEE International Symposium on Information Theory, ISIT 2008 |
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Country | Canada |

City | Toronto, ON |

Period | 7/6/08 → 7/11/08 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Theoretical Computer Science
- Information Systems
- Modeling and Simulation
- Applied Mathematics

### Cite this

*Proceedings - 2008 IEEE International Symposium on Information Theory, ISIT 2008*(pp. 1263-1267). [4595190] (IEEE International Symposium on Information Theory - Proceedings). https://doi.org/10.1109/ISIT.2008.4595190

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*Proceedings - 2008 IEEE International Symposium on Information Theory, ISIT 2008.*, 4595190, IEEE International Symposium on Information Theory - Proceedings, pp. 1263-1267, 2008 IEEE International Symposium on Information Theory, ISIT 2008, Toronto, ON, Canada, 7/6/08. https://doi.org/10.1109/ISIT.2008.4595190

**Can feedback, cooperation, relays and full duplex operation increase the degrees of freedom of wireless networks?** / Cadambe, Viveck R.; Jafar, Syed A.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

TY - GEN

T1 - Can feedback, cooperation, relays and full duplex operation increase the degrees of freedom of wireless networks?

AU - Cadambe, Viveck R.

AU - Jafar, Syed A.

PY - 2008/9/29

Y1 - 2008/9/29

N2 - We consider a fully connected network with S full duplex source nodes, D full duplex destination nodes and R relay nodes, perfect feedback to source and relay nodes, and noisy cooperation between all source, relay and destination nodes. We show that this network has SD/S+D-1 degrees of freedom if the channel gains are time-varying/frequency selective. The implication of the result is that, the techniques mentioned in the title (i.e relays etc.) can affect the capacity of a network only upto a o(log(SNR,)) term and therefore cannot improve the degrees of freedom of a network. Certain communication scenarios excluded by our system model where these techniques improve the degrees of freedom are also identified. Bounds on the degrees of freedom of a fully connected K node network emerge as a by-product of our study.

AB - We consider a fully connected network with S full duplex source nodes, D full duplex destination nodes and R relay nodes, perfect feedback to source and relay nodes, and noisy cooperation between all source, relay and destination nodes. We show that this network has SD/S+D-1 degrees of freedom if the channel gains are time-varying/frequency selective. The implication of the result is that, the techniques mentioned in the title (i.e relays etc.) can affect the capacity of a network only upto a o(log(SNR,)) term and therefore cannot improve the degrees of freedom of a network. Certain communication scenarios excluded by our system model where these techniques improve the degrees of freedom are also identified. Bounds on the degrees of freedom of a fully connected K node network emerge as a by-product of our study.

UR - http://www.scopus.com/inward/record.url?scp=52349089602&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=52349089602&partnerID=8YFLogxK

U2 - 10.1109/ISIT.2008.4595190

DO - 10.1109/ISIT.2008.4595190

M3 - Conference contribution

AN - SCOPUS:52349089602

SN - 9781424422579

T3 - IEEE International Symposium on Information Theory - Proceedings

SP - 1263

EP - 1267

BT - Proceedings - 2008 IEEE International Symposium on Information Theory, ISIT 2008

ER -