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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/49324

Title: 異構無線感知網路下可動態調整使用頻道比率之跳頻協定
Ratio-Adjustable Channel Hopping Enhancement for Heterogeneous Cognitive Radio Networks
Authors: Peng, Yu-Ru
彭郁茹
Contributors: NTOU:Department of Computer Science and Engineering
國立臺灣海洋大學:資訊工程學系
Keywords: 異構無線感知網路;碰面問題;跳頻;中國餘式定理
Heterogeneous Cognitive Radio Networks;Rendezvous Problem;Channel Hopping;Chinese Remainder Theorem
Date: 2015
Issue Date: 2018-08-22T06:56:38Z
Abstract: 在無線感知網路中,任兩個節點要能通訊的前提是這兩個節點能「碰面」,即這兩個節點同時切換到相同的可用頻道上。現存解決碰面問題的跳頻方法,大多是運作於同構式環境,即所有節點配備相同類型的通訊裝置,偵測相同的頻道範圍。但在實際的環境中,節點可能配備不同類型的通訊裝置,使得偵測頻道範圍並不相同,在這樣現實的異構式環境中。設計一個保證任兩個節點碰面的跳頻方法並不容易。此外,現存的跳頻方法都沒有考慮不同的頻道有不同的可用狀況,而是很平均地跳至每一個頻道,這樣的作法顯然有許多改善空間。在本篇文章中,我們設計了一個在異構無線感知網路環境下可動態調整頻道使用率的跳頻方法,RACH。執行RACH的節點會利用連續的三個連續奇數決定其跳至某一個頻道的排程,透過不同組的三個連續奇數會互質的特性,RACH可保證任兩個節點皆可碰面。RACH的跳頻機制亦允許每個節點依根據頻道狀況來調整頻道的使用比例,讓狀況較佳的頻道有較高的使用比例,以增加節點碰面機率。模擬結果顯示RACH確實能有效降低碰面間隔時間並增加系統效能。
In a cognitive radio network (CRN), a premise for two nodes to communicate is having a rendezvous which means that they switch to the same channel simultaneously. Most existing channel hopping solutions for the rendezvous problem is for a homogeneous CRN where nodes have the same type of cognitive radio and thus can sense the same spectrum. In reality, nodes have different types of cognitive radios and hence the spectrums being sensed are different. In such a heterogeneous CRN, designing a channel hopping mechanism to provide rendezvous guarantee is challenging. Besides, while determining the channel hopping sequences, existing channel hopping protocols enable nodes to switch to all the channels with the same probability. Such mechanisms are suboptimal since they do not consider different channel conditions of different channels. In this paper, we propose a channel hopping protocol for heterogeneous CRNs, RACH, which provides rendezvous guarantee between any pair of nodes and enables a node to dynamically adjust the ratio of each channel being used. Nodes running RACH use three consecutive odd numbers to determine the schedule for a particular channel. Utilizing the property that two different sets of three consecutive odd numbers are relatively primes, RACH provides rendezvous guarantee on each channel for two nodes. RACH allows nodes to change the set of consecutive odd numbers to adjust the ratio of a channel being switched to. Such a mechanism enables a node to tune to a better channel more to enhance its rendezvous probability to other nodes. Simulation results verify that RACH improves network performance in terms of time to rendezvous and throughput when compared with an existing channel hopping protocol for heterogeneous CRNs.
URI: http://ethesys.lib.ntou.edu.tw/cgi-bin/gs32/gsweb.cgi?o=dstdcdr&s=G0010257052.id
http://ntour.ntou.edu.tw:8080/ir/handle/987654321/49324
Appears in Collections:[資訊工程學系] 博碩士論文

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