## תקציר

A wireless ad-hoc network is a collection of transceivers positioned in the plane. Each transceiver is equipped with a limited battery charge. The battery charge is then reduced after each transmission, depending on the transmission distance. One of the major problems in wireless network design is to route network traffic efficiently so as to maximize the network lifetime, i.e., the number of successful transmissions. In this paper we consider Rooted Maximum Lifetime Broadcast/Convergecast problems in wireless settings. The instance consists of a directed graph G = (V,E) with edge-weights {w(e) : e ∈ E}, node capacities {b(υ) : υ ∈ V}, and a root r. The goal is to find a maximum size collection {T _{1}, ..., T _{k} } of Broadcast/Convergecast trees rooted at r so that ∑_{i=1}^{k} w(δ_{Ti}(υ)) ≤ b (υ),, where δ _{T} (υ) is the set of edges leaving υ in T. In the Single Topology version all the Broadcast/Convergecast trees T _{i} are identical. We present a number of polynomial time algorithms giving constant ratio approximation for various broadcast and convergecast problems, improving previously known result of Ω(⌊1/log n ⌋)-approximation by [1]. We also consider a generalized Rooted Maximum Lifetime Mixedcast problem, where we are also given an integer γ≥ 0, and the goal is to find the maximum integer k so that k Broadcast and γk Convergecast rounds can be performed.

שפה מקורית | אנגלית |
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כותר פרסום המארח | Algorithmic Aspects of Wireless Sensor Networks - 5th International Workshop, ALGOSENSORS 2009, Revised Selected Papers |

עמודים | 41-51 |

מספר עמודים | 11 |

מזהי עצם דיגיטלי (DOIs) | |

סטטוס פרסום | פורסם - 2009 |

אירוע | 5th International Workshop on Algorithmic Aspects of Wireless Sensor Networks, ALGOSENSORS 2009 - Rhodes, יוון משך הזמן: 10 יולי 2009 → 11 יולי 2009 |

### סדרות פרסומים

שם | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |
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כרך | 5804 LNCS |

ISSN (מודפס) | 0302-9743 |

ISSN (אלקטרוני) | 1611-3349 |

### כנס

כנס | 5th International Workshop on Algorithmic Aspects of Wireless Sensor Networks, ALGOSENSORS 2009 |
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מדינה/אזור | יוון |

עיר | Rhodes |

תקופה | 10/07/09 → 11/07/09 |

### הערה ביבליוגרפית

Funding Information:We thank anonymous referees for their valuable comments that significantly improved the presentation of the paper. The second author was supported in part by US Air Force, European Office of Aerospace Research and Development, Grant# FA8655-09-1-3016.