Pub Date : 2008-09-01DOI: 10.1109/ATNAC.2008.4783342
I. Ahmad, D. Habibi, Ziaur Rahman
WiMAX has emerged as a promising wireless communication technology with potential to deliver high throughput and guaranteed quality of service to the end applications. Recent studies suggest that while WiMAX (802.16e) is capable of delivering a data rate of up to 75 Mbps for fixed wireless communications, data rate decreases drastically for mobile wireless communications, often providing a data rate less than 1 Mb/s when the mobile nodes travel at vehicular speeds. High bit error rate caused at high vehicular speeds is the key reason for low throughput. In noisy mobile communication environments, standard error control mechanisms like the transmission control protocol (TCP) has limited and often detrimental impacts on the overall throughput because of the excessive retransmission overheads. To address this issue, WiMAX standard incorporates forward error correction (FEC) mechanism that eliminates the need for retransmissions. In FEC, extra parity bits are added to the original message to recover the corrupted information. Adaptive FEC that adjusts the size of extra parity bits in response to packet retransmission requests is an enhancement over standard FEC that uses fixed block of party bits. Existing adaptive FEC schemes, however, have limited efficiency when the end terminal moves at vehicular speeds. In this paper, we propose a new FEC scheme that estimates and adjusts the size of extra parity bits to suit the channel conditions. We apply the concept of interval based data sampling to address the dynamic nature of communication environments at high vehicular speeds.
{"title":"An Improved FEC Scheme for Mobile Wireless Communication at Vehicular Speeds","authors":"I. Ahmad, D. Habibi, Ziaur Rahman","doi":"10.1109/ATNAC.2008.4783342","DOIUrl":"https://doi.org/10.1109/ATNAC.2008.4783342","url":null,"abstract":"WiMAX has emerged as a promising wireless communication technology with potential to deliver high throughput and guaranteed quality of service to the end applications. Recent studies suggest that while WiMAX (802.16e) is capable of delivering a data rate of up to 75 Mbps for fixed wireless communications, data rate decreases drastically for mobile wireless communications, often providing a data rate less than 1 Mb/s when the mobile nodes travel at vehicular speeds. High bit error rate caused at high vehicular speeds is the key reason for low throughput. In noisy mobile communication environments, standard error control mechanisms like the transmission control protocol (TCP) has limited and often detrimental impacts on the overall throughput because of the excessive retransmission overheads. To address this issue, WiMAX standard incorporates forward error correction (FEC) mechanism that eliminates the need for retransmissions. In FEC, extra parity bits are added to the original message to recover the corrupted information. Adaptive FEC that adjusts the size of extra parity bits in response to packet retransmission requests is an enhancement over standard FEC that uses fixed block of party bits. Existing adaptive FEC schemes, however, have limited efficiency when the end terminal moves at vehicular speeds. In this paper, we propose a new FEC scheme that estimates and adjusts the size of extra parity bits to suit the channel conditions. We apply the concept of interval based data sampling to address the dynamic nature of communication environments at high vehicular speeds.","PeriodicalId":143803,"journal":{"name":"2008 Australasian Telecommunication Networks and Applications Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133964974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-07-10DOI: 10.1109/ATNAC.2008.4783352
Masafumi Hashimoto, G. Hasegawa, M. Murata
In this paper, we first evaluate the performance of recent TCP variants for high-speed and long-delay networks in IEEE 802.11 wireless LAN environment through simulation experiments. We show that some of them still have well-known TCP unfairness property between uplink and downlink flows, and that there is another unfairness problem among uplink flows caused by the loss-based behavior of hybrid TCP variants. We then propose an end-to-end-basis modification to TCP congestion control mechanisms to alleviate the unfairness problems, which activates the congestion control when detecting ACK packet losses. Through simulation experiments, we present that the proposed method is effective not only for TCP fairness among uplink flows but also for fairness between uplink and downlink flows, while keeping the total throughput to be large enough.
{"title":"Performance Evaluation and Improvement of Hybrid TCP Congestion Control Mechanisms in Wireless LAN Environment","authors":"Masafumi Hashimoto, G. Hasegawa, M. Murata","doi":"10.1109/ATNAC.2008.4783352","DOIUrl":"https://doi.org/10.1109/ATNAC.2008.4783352","url":null,"abstract":"In this paper, we first evaluate the performance of recent TCP variants for high-speed and long-delay networks in IEEE 802.11 wireless LAN environment through simulation experiments. We show that some of them still have well-known TCP unfairness property between uplink and downlink flows, and that there is another unfairness problem among uplink flows caused by the loss-based behavior of hybrid TCP variants. We then propose an end-to-end-basis modification to TCP congestion control mechanisms to alleviate the unfairness problems, which activates the congestion control when detecting ACK packet losses. Through simulation experiments, we present that the proposed method is effective not only for TCP fairness among uplink flows but also for fairness between uplink and downlink flows, while keeping the total throughput to be large enough.","PeriodicalId":143803,"journal":{"name":"2008 Australasian Telecommunication Networks and Applications Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122378371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ATNAC.2008.4783332
Ming Li
One of the key challenges in geographic routing is how to deal with dead-ends, where greedy routing fails to find a neighbor node which is closer to the destination. Most existing geographic routing algorithms just switch to the deterministic face routing or limits its face searching range. In this paper, we demonstrate that we can improve routing performance by considering local connectivity status at each node before making routing decision. We present a protocol, Density Ripple Exchange (DRE), that maintains local density information at each node, and a new geographic routing algorithm, Geographic Ripple Routing (GRR), that achieves better routing performance in both hop stretch and transmission stretch than existing geographic routing algorithms by exploiting available connectivity information. Our simulations demonstrate that we increased the performance for GRR over Greedy Perimeter Stateless Routing (GPSR) by about 15%. The cost of this improved performance is a small amount of additional local connectivity information required for our algorithm.
{"title":"Ripple Effect: an Improved Geographic Routing with Local Connectivity Information","authors":"Ming Li","doi":"10.1109/ATNAC.2008.4783332","DOIUrl":"https://doi.org/10.1109/ATNAC.2008.4783332","url":null,"abstract":"One of the key challenges in geographic routing is how to deal with dead-ends, where greedy routing fails to find a neighbor node which is closer to the destination. Most existing geographic routing algorithms just switch to the deterministic face routing or limits its face searching range. In this paper, we demonstrate that we can improve routing performance by considering local connectivity status at each node before making routing decision. We present a protocol, Density Ripple Exchange (DRE), that maintains local density information at each node, and a new geographic routing algorithm, Geographic Ripple Routing (GRR), that achieves better routing performance in both hop stretch and transmission stretch than existing geographic routing algorithms by exploiting available connectivity information. Our simulations demonstrate that we increased the performance for GRR over Greedy Perimeter Stateless Routing (GPSR) by about 15%. The cost of this improved performance is a small amount of additional local connectivity information required for our algorithm.","PeriodicalId":143803,"journal":{"name":"2008 Australasian Telecommunication Networks and Applications Conference","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133334660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ATNAC.2008.4783303
S. Marwaha, J. Indulska, M. Portmann
Mobile ad hoc networks (MANET), which comprise of mobile nodes connected wirelessly, are emerging as a very important technology for future generation of wireless mobile and ubiquitous computing. MANETs are being used in numerous application domains from emergency rescue and relief to wireless sensor networks. To support real-time communications (such as audio and video) over MANETs, new quality of service (QoS) provisioning mechanisms need to be developed. There are many challenges in QoS provisioning for MANETs such as dynamically changing topology, wireless capacity limitations, heterogeneous network environment, limited battery power etc. Previous QoS surveys in MANET have only looked at QoS provisioning models, signaling and routing. This paper presents a complete survey of the challenges and current state of the art of MANET QoS routing, signaling and MAC protocols as well as the various MANET QoS models that are being developed.
{"title":"Challenges and Recent Advances in QoS Provisioning, Signaling, Routing and MAC protocols for MANETs","authors":"S. Marwaha, J. Indulska, M. Portmann","doi":"10.1109/ATNAC.2008.4783303","DOIUrl":"https://doi.org/10.1109/ATNAC.2008.4783303","url":null,"abstract":"Mobile ad hoc networks (MANET), which comprise of mobile nodes connected wirelessly, are emerging as a very important technology for future generation of wireless mobile and ubiquitous computing. MANETs are being used in numerous application domains from emergency rescue and relief to wireless sensor networks. To support real-time communications (such as audio and video) over MANETs, new quality of service (QoS) provisioning mechanisms need to be developed. There are many challenges in QoS provisioning for MANETs such as dynamically changing topology, wireless capacity limitations, heterogeneous network environment, limited battery power etc. Previous QoS surveys in MANET have only looked at QoS provisioning models, signaling and routing. This paper presents a complete survey of the challenges and current state of the art of MANET QoS routing, signaling and MAC protocols as well as the various MANET QoS models that are being developed.","PeriodicalId":143803,"journal":{"name":"2008 Australasian Telecommunication Networks and Applications Conference","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125035528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ATNAC.2008.4783301
Ashley Chonka, Wanlei Zhou, Y. Xiang
Today's security program developers are not only facing an uphill battle of developing and implementing. But now have to take into consideration, the emergence of next generation of multi-core system, and its effect on security application design. In our previous work, we developed a framework called bodyguard. The objective of this framework was to help security software developers, shift from their use of serialized paradigm, to a multi-core paradigm. Working within this paradigm, we developed a security bodyguard system called Farmer. This abstract framework placed particular applications into categories, like security or multi-media, which were ran on separate core processors within the multi-core system. With further analysis of the bodyguard paradigm, we found that this paradigm was suitable to be used in other computer science areas, such as spam filtering and multi-media. In this paper, we update our research work within the bodyguard paradigm, and showed a marked improvement of 110% speedup performance with an average cost of 1.5 ms.
{"title":"Multi-core Security Defense System (MSDS)","authors":"Ashley Chonka, Wanlei Zhou, Y. Xiang","doi":"10.1109/ATNAC.2008.4783301","DOIUrl":"https://doi.org/10.1109/ATNAC.2008.4783301","url":null,"abstract":"Today's security program developers are not only facing an uphill battle of developing and implementing. But now have to take into consideration, the emergence of next generation of multi-core system, and its effect on security application design. In our previous work, we developed a framework called bodyguard. The objective of this framework was to help security software developers, shift from their use of serialized paradigm, to a multi-core paradigm. Working within this paradigm, we developed a security bodyguard system called Farmer. This abstract framework placed particular applications into categories, like security or multi-media, which were ran on separate core processors within the multi-core system. With further analysis of the bodyguard paradigm, we found that this paradigm was suitable to be used in other computer science areas, such as spam filtering and multi-media. In this paper, we update our research work within the bodyguard paradigm, and showed a marked improvement of 110% speedup performance with an average cost of 1.5 ms.","PeriodicalId":143803,"journal":{"name":"2008 Australasian Telecommunication Networks and Applications Conference","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129729594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/cleo.2007.4453259
The document that should appear here is not currently available.
这里应该出现的文档目前不可用。
{"title":"PDF Not Yet Available In IEEE Xplore","authors":"","doi":"10.1109/cleo.2007.4453259","DOIUrl":"https://doi.org/10.1109/cleo.2007.4453259","url":null,"abstract":"The document that should appear here is not currently available.","PeriodicalId":143803,"journal":{"name":"2008 Australasian Telecommunication Networks and Applications Conference","volume":"198 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122342421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/ATNAC.2008.4783339
R. Wishart, M. Portmann, J. Indulska
In public safety and disaster recovery (PSDR) scenarios, reliable communication is an imperative. Unfortunately, communication infrastructure is often destroyed or overwhelmed by whatever precipitated the scenario (e.g., a hurricane or terrorist attack). Thus, the PSDR workers must often deploy their own communications infrastructure on-site. Wireless mesh networks (WMN) have been identified as being ideally suited to this task. WMN offer a high-capacity wireless backhaul network, provided by mesh routers, through which clients can connect to one another or with external networks. Mobility of clients within the mesh is particularly important for public service and disaster recovery scenarios. This creates a challenging problem as clients may move out of range of the mesh router they were using to connect to the mesh and need to associate with another. Client handoff mechanisms provide this functionality. In this paper we provide a critical survey of client handoff approaches applicable to IEEE 802.11 WMN evaluating them based on the strict QoS requirements established by the US Department of Homeland Security for PSDR networks.
{"title":"Evaluation of Wireless Mesh Network Handoff Approaches for Public Safety and Disaster Recovery Networks","authors":"R. Wishart, M. Portmann, J. Indulska","doi":"10.1109/ATNAC.2008.4783339","DOIUrl":"https://doi.org/10.1109/ATNAC.2008.4783339","url":null,"abstract":"In public safety and disaster recovery (PSDR) scenarios, reliable communication is an imperative. Unfortunately, communication infrastructure is often destroyed or overwhelmed by whatever precipitated the scenario (e.g., a hurricane or terrorist attack). Thus, the PSDR workers must often deploy their own communications infrastructure on-site. Wireless mesh networks (WMN) have been identified as being ideally suited to this task. WMN offer a high-capacity wireless backhaul network, provided by mesh routers, through which clients can connect to one another or with external networks. Mobility of clients within the mesh is particularly important for public service and disaster recovery scenarios. This creates a challenging problem as clients may move out of range of the mesh router they were using to connect to the mesh and need to associate with another. Client handoff mechanisms provide this functionality. In this paper we provide a critical survey of client handoff approaches applicable to IEEE 802.11 WMN evaluating them based on the strict QoS requirements established by the US Department of Homeland Security for PSDR networks.","PeriodicalId":143803,"journal":{"name":"2008 Australasian Telecommunication Networks and Applications Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125734873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/pedes.2006.344308
The document that should appear here is not currently available.
这里应该出现的文档目前不可用。
{"title":"PDF Not Yet Available In IEEE Xplore","authors":"","doi":"10.1109/pedes.2006.344308","DOIUrl":"https://doi.org/10.1109/pedes.2006.344308","url":null,"abstract":"The document that should appear here is not currently available.","PeriodicalId":143803,"journal":{"name":"2008 Australasian Telecommunication Networks and Applications Conference","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115405196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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