Spatial query processing in vehicular ad-hoc networks
基於車載網絡的空間查詢
Student thesis: Master's Thesis
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Detail(s)
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Award date | 14 Feb 2014 |
Link(s)
Permanent Link | https://scholars.cityu.edu.hk/en/theses/theses(bcb859e9-11d9-4855-9548-e741400728e9).html |
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Other link(s) | Links |
Abstract
Location-based services (LBS) are information and entertainment services which are
accessible from the mobile device through the mobile network based on the geographical
position of the mobile device at the time of request. LBS are an abstraction of spatial
queries, e.g., range and k-nearest-neighbor (k-NN) queries. Due to the spatial locality
of LBS, a lot of recent research has shown that peer-to-peer (P2P) cooperation is
an effective and efficient technique to improve the performance of LBS systems. With
the new IEEE standardization of Dedicated Short Range Communication (DSRC)/ Wireless
Access in Vehicular Environments (WAVE), Vehicular Ad Hoc Networks (VANETs)
which are designed for data exchange between high-speed vehicles and between the
roadside infrastructure and the vehicle have recently reemerged as a promising mobile
computing platform. Both LBS and VANETs have been well studied, but most existing
VANET-based LBS only support simple information dissemination applications. It becomes
a very timely topic to develop a new VANET-based framework to support spatial
queries. VANETs have many unique characteristics compared to mobile ad hoc networks
(MANETs) including road network constraints, mobility prediction, frequent disconnection
and ample energy and capacity. These key characteristics make existing MANETbased
LBS frameworks not suitable for high-speed vehicles.
In this thesis, we investigate the above unique characteristics of VANETs. A comprehensive
survey of mobile peer-to-peer data dissemination and query processing is presented.
According to the characteristics and the present works, we discuss some open
challenges in VANET-based LBS. Specifically, to better understand the access between
vehicles and roadside units, an analytical study on cooperative data dissemination in
push-based mobile P2P networks is conducted. We propose a spatial query processing framework with cooperative data dissemination in VANETs. In the proposed k-NN query
processing framework, we design the road-based semantic caching, statistics-based query
time-to-live estimation, and hybrid routing techniques to enable k-NN query processing
in VANETs. Based on this framework, road-side units (RSUs) are utilized as an infrastructure
support to facilitate spatial query processing with cooperative data dissemination
in VANETs. Besides, we propose the cache sharing optimization for cooperative data
dissemination in VANETs. Experiment results show that cooperative data dissemination
techniques such as vehicle-roadside access and cache sharing significantly improve the
system performance in terms of query response time, answer accuracy and communication
overhead.
- Querying (Computer science), Vehicular ad hoc networks (Computer networks)