作者:Chen Feng and Xu Jiakai
出處: Wireless Communications and Signal Processing (WCSP),
2010 International Conference on ,no.5
學生:黃群凱
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 INTRODUCTION
 THE AD HOC ROUTING STRATEGIES
 SIMULATION ENVIRONMENT AND
NETWORK
 SIMULATION RESULTS AND
ANALYSIS
 CONCLUSIONS
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 In recent years, the research on the intelligent
transportation system (ITS) has been progressing
intensively.
 ITS uses information communication technologies
to connect “the person”, “the road”, and “the
vehicle” as one system.
 The transmission technology for ITS can be
typically classified into two categories, i.e.
 Road-to-vehicle communications (RVC)
 Inter-vehicle communications (IVC).
 The traditional proactive routing protocols are
designed to discover the routes of node pairs
between all the source nodes and the target nodes.
 This greatly increases the routing overhead.
 As reactive routing protocols, AODV and DSR
have the common characteristic that the route
discovery process is initialized on-demand and
only when the routes need to be transmitted by
the data packets.
 It greatly decreases the routing overhead.
 AODV Routing Protocol
 Route Requests(RREQs)的發送
 檢查它的Routing Table
 找不到可到達Destination Node 的Route Entry
 廣播Route Requests (RREQs)去尋找新路徑
 Route Replies (RREPs) 之發送
 當 RREQs 的訊息到達它所指定的 Destination Node，便會
傳回Route Replies (RREPs)
 收到 RREQ 的訊息後，發現 RREQ 中所記載的Destination
Address 是自己，則會先依據RREQ 中所記載的 Address
Sequence 去更改 Routing Table
 AODV Routing Protocol
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 Dynamic source routing(DSR)
 是 Source Routing 的觀念，將路由資訊直接紀錄在每個
封包裡，特殊的環境中使用，DSR 也是在需要路徑的時
侯才去找尋路徑。
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1.
No significant power constraint “Unlike” in sensor
and other ad hoc networks, battery life is not limited.
2.
High mobility and rapidly changing topology
“Vehicles” move very fast especially on highways.
3.
Predictable mobility “Vehicle” mobility is
constrained by road geometry.
4.
Additional information for protocol optimization
“Equipment” like GPS devices or a digital road
map can be integrated into the communication
system because power is not limited, sufficient
space is available, and the cost of these devices
are usually small compared to the cost of a
vehicle.
 the DSR is better than AODV under relative loose
condition (i.e. less nodes and less mobility) and the
AODV is better than DSR under relative rigorous
condition has been derived.
 The AODV protocol is more adapt to the VANET for
the high speed and complicated transportation system
than the DSR protocol.
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