13-02-2013, 02:33 PM
Cooperative Data Dissemination via Roadside WLANs
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Abstract
Data dissemination services embrace a wide variety of telematic applications where data packets are generated at a remote server in the Internet and destined to a group of nomadic users such as vehicle passengers and pedestrians. The quality of a data dissemination service is highly dependent on the availability of network infrastructures in terms of the access points (APs). In this article, we investigate the utilization of roadside wireless local area networks (RSWLANs) as a network infrastructure for data dissemination. A two-level cooperative data dissemination approach is presented. With the network-level cooperation, the resources in the RS-WLANs are used to facilitate the data dissemination services for the nomadic users. The packet-level cooperation is exploited to improve the packet transmission rate to a nomadic user. Various techniques for the two levels of cooperation are discussed. A case study is presented to evaluate the performance of the data dissemination approach.
DTCoop Scheme
A delay tolerant cooperation (DTCoop) scheme is proposed. Based the DTCoop scheme, data packets are pre-downloaded to not only the AP but also the storage local transceivers within an RS-WLAN, and the channel diversity is exploited in scheduling the transmission of the pre-downloaded packets upon each visit of a nomadic user. An illustration of the packet scheduling under the DTCoop scheme is shown in Following Fig. 2. Within an RS-WLAN, there are three entities which can participate in the cooperation, i.e., the AP, storage local transceivers, and non-storage local transceivers. There are four possible transmission links to deliver a packet to a nomadic user, i.e., the direct links from the AP and a storage local transceiver, and the relay links from the AP and a storage local transceiver with the help of a non-storage local transceiver. Among the links, the one with the maximum transmission rate is selected.
Existing System
The data dissemination services can be supported by the traditional cellular networks such as general packet radio service (GPRS) and 3G. However, as cellular networks aim at offering ubiquitous network coverage, providing the data dissemination services by cellular networks can suffer from low transmission rate and high cost.
Disadvantages:
1. A local user moves at a low speed and can stay within the coverage area.
2. No energy constraint for the AP.
3. Limited bandwidth of the wire-line connection.
[attachment=50700]
Abstract
Data dissemination services embrace a wide variety of telematic applications where data packets are generated at a remote server in the Internet and destined to a group of nomadic users such as vehicle passengers and pedestrians. The quality of a data dissemination service is highly dependent on the availability of network infrastructures in terms of the access points (APs). In this article, we investigate the utilization of roadside wireless local area networks (RSWLANs) as a network infrastructure for data dissemination. A two-level cooperative data dissemination approach is presented. With the network-level cooperation, the resources in the RS-WLANs are used to facilitate the data dissemination services for the nomadic users. The packet-level cooperation is exploited to improve the packet transmission rate to a nomadic user. Various techniques for the two levels of cooperation are discussed. A case study is presented to evaluate the performance of the data dissemination approach.
DTCoop Scheme
A delay tolerant cooperation (DTCoop) scheme is proposed. Based the DTCoop scheme, data packets are pre-downloaded to not only the AP but also the storage local transceivers within an RS-WLAN, and the channel diversity is exploited in scheduling the transmission of the pre-downloaded packets upon each visit of a nomadic user. An illustration of the packet scheduling under the DTCoop scheme is shown in Following Fig. 2. Within an RS-WLAN, there are three entities which can participate in the cooperation, i.e., the AP, storage local transceivers, and non-storage local transceivers. There are four possible transmission links to deliver a packet to a nomadic user, i.e., the direct links from the AP and a storage local transceiver, and the relay links from the AP and a storage local transceiver with the help of a non-storage local transceiver. Among the links, the one with the maximum transmission rate is selected.
Existing System
The data dissemination services can be supported by the traditional cellular networks such as general packet radio service (GPRS) and 3G. However, as cellular networks aim at offering ubiquitous network coverage, providing the data dissemination services by cellular networks can suffer from low transmission rate and high cost.
Disadvantages:
1. A local user moves at a low speed and can stay within the coverage area.
2. No energy constraint for the AP.
3. Limited bandwidth of the wire-line connection.