Ad-Hoc無線網路中設計一具有頻道重覆使用特性的動態頻道安排及重安排協定

 

Dynamic Channel Assignment and Reassignment for Exploiting Channel Reuse Opportunities for Mobile Hosts in Ad-Hoc Networks

 

黃博治 Po-Chih Huang

私立真理大學數理科學研究所

台北縣淡水鎮真理街32號

Tel : (02) 26212121-5204

jackalPChuang@giga.net.tw

 

陳裕賢 Yuh-Shyan Chen

台北大學統計系

台北市民生東路三段67號

Tel : (02) 2500-9837

yschen@mail.ntpu.edu.tw

 

張志勇 Chih-Yung Chang

真理大學資訊科學系

台北縣淡水鎮真理街32號

Tel : (02) 26212121-5222

changcy@email.au.edu.tw

 

 

摘要

Ad-Hoc無線網路的環境中,一對hosts的通訊必須佔用一個channel,在其通訊範圍內若有另一對hosts使用相同的channel通訊,將造成訊號干擾,由於channel是有限資源,重複使用channel將是提高channel使用率,解決channel數不足的可行方案。但是,提高channel 的重複使用率,卻產生另一個問題:由於每個host均可任意移動,當正在通訊的host移動到使用相同channel的通訊範圍時,會干擾正在通訊的host,這時必須對產生干擾的hosts執行channel reassignment的協定,受到干擾的hosts始能再繼續通訊而不致斷訊。

本論文主要目的在探討channel的安排方式,使頻道資源不但能得到最高的重複使用率,當host因移動而造成干擾時,我們亦提出一個dynamic channel reassignment protocol,使正在通訊的hosts能避開干擾並繼續通訊。在這篇論文中,我們提出的dynamic channel reassignment protocol可以使彼此干擾的host能在有效率且低成本的考量下快速更換到適當的channel而繼續通訊,我們亦針對現有的頻道安排及重安排的相關協定,將其實作於模擬器中,實驗顯示,本論文所提出的頻道安排及重安排協定,可有效減少因移動性而造成斷訊的機會,進而使通訊效能提升。

 

 

Abstract

In an Ad-Hoc wireless network, the communication of a pair of hosts should consume one channel. The co-channel interference is occurred if there are two pairs of hosts using the same channel for their own communication. Due to that channel is a limited resource, exploiting channel reuse opportunities will improve the channel utilization and increase the number of pairs in communication. However, exploiting channel reuse opportunity creates problem of co-channel interference owing to mobility. As two pairs of communicating hosts that use the same channel move closely to each other, a channel reassignment operation is needed for preventing the communication from break. This paper mainly focuses on developing a channel assignment protocol for exploiting the channel reuse opportunities. In addition, we develop a channel reassignment protocol for resolving the co-channel interference problem. Comparisons of the proposed protocols and the related work are made in experimental study. Simulation results show that the proposed channel assignment and reassignment protocols effectively reduce the probability of communication break and thus improve the system performance.

 

關鍵字 Ad-Hoc, wireless networks, channel assignment, channel reassignment, co-channel interference